NTP TECHNICAL REPORT
 

ON THE
 

TOXICOLOGY AND CARCINOGENESIS
 

STUDIES OF
 

AZT
 (CAS NO. 30516-87-1)
 

AND
 

AZT/"-INTERFERON A/D
 

IN B6C3F1 MICE

(GAVAGE STUDIES) 

NATIONAL TOXICOLOGY PROGRAM
 

P.O. Box 12233
 

Research Triangle Park, NC 27709
 

February 1999 

NTP TR 469
 

NIH Publication No. 99-3959
 

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
 

Public Health Service
 

National Institutes of Health
 
FOREWORD 

The National Toxicology Program (NTP) is made up of four charter agencies of the U.S. Department of 

Health and Human Services (DHHS): the National Cancer Institute (NCI), National Institutes of Health; the 

National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health; the National 

Center for Toxicological Research (NCTR), Food and Drug Administration; and the National Institute for 

Occupational Safety and Health (NIOSH), Centers for Disease Control. In July 1981, the Carcinogenesis 

Bioassay Testing Program, NCI, was transferred to the NIEHS. The NTP coordinates the relevant 

programs, staff, and resources from these Public Health Service agencies relating to basic and applied 

research and to biological assay development and validation. 

The NTP develops, evaluates, and disseminates scientific information about potentially toxic and hazardous 

chemicals. This knowledge is used for protecting the health of the American people and for the primary 

prevention of disease. 

The studies described in this Technical Report were performed under the direction of the NIEHS and were 

conducted in compliance with NTP laboratory health and safety requirements and must meet or exceed all 

applicable federal, state, and local health and safety regulations. Animal care and use were in accordance 

with the Public Health Service Policy on Humane Care and Use of Animals. The prechronic and chronic 

studies were conducted in compliance with Food and Drug Administration (FDA) Good Laboratory Practice 

Regulations, and all aspects of the chronic studies were subjected to retrospective quality assurance audits 

before being presented for public review. 

These studies are designed and conducted to characterize and evaluate the toxicologic potential, including 

carcinogenic activity, of selected chemicals in laboratory animals (usually two species, rats and mice). 

Chemicals selected for NTP toxicology and carcinogenesis studies are chosen primarily on the bases of 

human exposure, level of production, and chemical structure. The interpretive conclusions presented in this 

Technical Report are based only on the results of these NTP studies. Extrapolation of these results to other 

species and quantitative risk analyses for humans require wider analyses beyond the purview of these 

studies. Selection per se is not an indicator of a chemical’s carcinogenic potential. 

Listings of all published NTP reports and ongoing studies are available from NTP Central Data 

Management, NIEHS, P.O. Box 12233, MD E1-02, Research Triangle Park, NC 27709 (919-541-3419). 

The Abstracts and other study information for 2-year studies are also available at the NTP’s World Wide 

Web site: http://ntp-server.niehs.nih.gov. 
NTP TECHNICAL REPORT
 

ON THE
 

TOXICOLOGY AND CARCINOGENESIS
 

STUDIES OF
 

AZT
 (CAS NO. 30516-87-1)
 

AND
 

AZT/"-INTERFERON A/D
 

IN B6C3F1 MICE

(GAVAGE STUDIES) 

NATIONAL TOXICOLOGY PROGRAM
 

P.O. Box 12233
 

Research Triangle Park, NC 27709
 

February 1999 

NTP TR 469
 

NIH Publication No. 99-3959
 

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
 

Public Health Service
 

National Institutes of Health
 
2 AZT and AZT/"-Interferon A/D, NTP TR 469 

CONTRIBUTORS
 

National Toxicology Program 

Evaluated and interpreted results and reported findings 

R.D. Irwin, Ph.D., Study Scientist 

D.A. Bridge, B.S. 

J.R. Bucher, Ph.D. 

R.E. Chapin, Ph.D. 

J.K. Haseman, Ph.D. 

R.R. Maronpot, D.V.M. 

A. Radovsky, D.V.M., Ph.D. 

G.N. Rao, D.V.M., Ph.D. 

J.H. Roycroft, Ph.D. 

C.S. Smith, Ph.D. 

G.S. Travlos, D.V.M. 

D.B. Walters, Ph.D. 

K.L. Witt, M.S., Oak Ridge Associated Universities 

Southern Research Institute 

Conducted studies, evaluated pathology findings 

J.D. Prejean, Ph.D., Principal Investigator (14-week study) 

D.G. Serota, Ph.D., Principal Investigator (2-year studies) 

D.R. Farnell, D.V.M., Ph.D. 

J.E. Heath, D.V.M. 

R.B. Thompson, D.V.M., Ph.D. 

Experimental Pathology Laboratories, Inc. 

Provided pathology quality assurance 

J.F. Hardisty, D.V.M., Principal Investigator 

E.T. Gaillard, D.V.M., M.S. 

C.C. Shackelford, D.V.M., M.S., Ph.D. 

Dynamac Corporation 

Prepared quality assurance audits 

S. Brecher, Ph.D., Principal Investigator 

NTP Pathology Working Group 

Evaluated slides, prepared pathology report on 2-year AZT study 

(22 February 1996) 

J.C. Seely, D.V.M., Chairperson 

PATHCO, Inc. 

K.M. Ayers, D.V.M. 

Glaxo Wellcome 

R. Cattley, V.M.D., Ph.D. 

Chemical Industry Institute of Toxicology 

E.T. Gaillard, D.V.M., M.S. 

Experimental Pathology Laboratories, Inc. 

J.R. Hailey, D.V.M. 

National Toxicology Program 

R.A. Herbert, D.V.M., Ph.D. 

National Toxicology Program 

A. Nyska, D.V.M., Observer 

National Toxicology Program 

A. Radovsky, D.V.M., Ph.D. 

National Toxicology Program 

Evaluated slides, prepared pathology report on 2-year "-interferon 

A/D study (18 June 1996) 

J.C. Seely, D.V.M., Chairperson 

PATHCO, Inc. 

R. Cattley, V.M.D., Ph.D. 

Chemical Industry Institute of Toxicology 

E.T. Gaillard, D.V.M., M.S. 

Experimental Pathology Laboratories, Inc. 

J.R. Hailey, D.V.M. 

National Toxicology Program 

R.A. Herbert, D.V.M., Ph.D. 

National Toxicology Program 

A. Nyska, D.V.M. 

National Toxicology Program 

A. Radovsky, D.V.M., Ph.D. 

National Toxicology Program 
AZT and AZT/"-Interferon A/D, NTP TR 469 3 

NTP Pathology Working Group (continued) 

Evaluated slides, prepared pathology report on 2-year AZT/500 U 

"-interferon A/D study (9 May 1996) 

J.C. Seely, D.V.M., Chairperson 

PATHCO, Inc. 

R. Cattley, V.M.D., Ph.D. 

Chemical Industry Institute of Toxicology 

J.R. Hailey, D.V.M. 

National Toxicology Program 

R.A. Herbert, D.V.M., Ph.D. 

National Toxicology Program 

V.-M. Kosma, M.D., Observer 

KTL Finnish National Public Health Institute 

A. Nyska, D.V.M. 

National Toxicology Program 

A. Radovsky, D.V.M., Ph.D. 

National Toxicology Program 

C.C. Shackelford, D.V.M., M.S., Ph.D. 

Experimental Pathology Laboratories, Inc. 

Analytical Sciences, Inc. 

Provided statistical analyses 

R.W. Morris, M.S., Principal Investigator 

S.R. Lloyd, M.S. 

N.G. Mintz, B.S. 

Evaluated slides, prepared pathology report on 2-year AZT/5,000 U 

"-interferon A/D study (2 April 1996) 

J.C. Seely, D.V.M., Chairperson 

PATHCO, Inc. 

K.M. Ayers, D.V.M., Observer 

Glaxo Wellcome 

R. Cattley, V.M.D., Ph.D. 

Chemical Industry Institute of Toxicology 

E.T. Gaillard, D.V.M., M.S. 

Experimental Pathology Laboratories, Inc. 

R.A. Herbert, D.V.M., Ph.D. 

National Toxicology Program 

A. Nyska, D.V.M. 

National Toxicology Program 

A. Radovsky, D.V.M., Ph.D. 

National Toxicology Program 

Biotechnical Services, Inc. 

Prepared Technical Report 

S.R. Gunnels, M.A., Principal Investigator 

J.R. Carlton, B.A. 

L.M. Harper, B.S. 

A.M. Macri-Hanson, M.A., M.F.A. 

M.J. Nicholls, B.S. 
4 

CONTENTS
 

ABSTRACT ............................................................. 7
 

EXPLANATION OF LEVELS OF EVIDENCE OF CARCINOGENIC ACTIVITY ............. 14
 

TECHNICAL REPORTS REVIEW SUBCOMMITTEE ................................ 15
 

SUMMARY OF TECHNICAL REPORTS REVIEW SUBCOMMITTEE COMMENTS .......... 16
 

INTRODUCTION ......................................................... 17
 

MATERIALS AND METHODS ................................................ 25
 

RESULTS ............................................................... 41
 

DISCUSSION AND CONCLUSIONS ............................................ 77
 

REFERENCES ........................................................... 83
 

APPENDIX A Summary of Lesions in Male Mice in the 2-Year Gavage Study of AZT .......... 91
 

APPENDIX B Summary of Lesions in Female Mice in the 2-Year Gavage Study of AZT ......... 107
 

APPENDIX C Summary of Lesions in Male Mice in the 2-Year Subcutaneous Study
 

of "-Interferon A/D ............................................. 123
 

APPENDIX D Summary of Lesions in Female Mice in the 2-Year Subcutaneous Study
 

of "-Interferon A/D ............................................. 139
 

APPENDIX E Summary of Lesions in Male Mice in the 2-Year Gavage Study 

of AZT/500 U "-Interferon A/D ..................................... 155
 

APPENDIX F Summary of Lesions in Female Mice in the 2-Year Gavage Study 

of AZT/500 U "-Interferon A/D ..................................... 169
 

APPENDIX G Summary of Lesions in Male Mice in the 2-Year Gavage Study 

of AZT/5,000 U "-Interferon A/D ................................... 183
 

APPENDIX H Summary of Lesions in Female Mice in the 2-Year Gavage Study 

of AZT/5,000 U "-Interferon A/D ................................... 197
 

APPENDIX I Genetic Toxicology ............................................. 213
 

APPENDIX J Organ Weights and Organ-Weight-to-Body-Weight Ratios .................. 223
 
AZT and AZT/"-Interferon A/D, NTP TR 469
 5 

APPENDIX K Hematology and Bone Marrow Analyses ............................... 227
 

APPENDIX L Reproductive Tissue Evaluations and Estrous Cycle Characterization ........... 293
 

APPENDIX M Neurobehavioral Data ........................................... 297
 

APPENDIX N Determinations of AZT Concentrations in Plasma ......................... 307
 

APPENDIX O Chemical Characterization and Dose Formulation Studies ................... 309
 

APPENDIX P Ingredients, Nutrient Composition, and Contaminant Levels 

in NIH-07 Rat and Mouse Ration .................................... 327
 

APPENDIX Q Sentinel Animal Program ......................................... 331
 

APPENDIX 1 R Impact of Helicobacter hepaticus Infection in B6C3F Mice 

from 12 NTP 2-Year Carcinogenesis Studies ............................ 337
 
6 AZT and AZT/"-Interferon A/D, NTP TR 469 
7 

ABSTRACT
 

HN 

N 

O 

CH3 

O 

O 

HOCH2 

N3 

3N-AZIDO-3N-DEOXYTHYMIDINE 

CAS No. 30516-87-1 

Chemical Formula: C 10 13 5 4 H N O Molecular Weight: 267.24 

Synonyms: 

Trade name: 

AZT; 3N-azido-2N,3N-dideoxythymidine; azidodeoxythymidine; azidothymidine; 3N-azidothymidine; 3N-deoxy-3N-azidothymidine; 

3N-deoxy-(8CI) (9CI); BW A509U; Compound S; ZDV; zidovudine 

Retrovir® 

3N-Azido-3N-deoxythymidine (AZT) is the most widely 

used and evaluated chemotherapeutic agent for the 

treatment of persons with acquired immune deficiency 

syndrome (AIDS) and persons seropositive for 

human immunodeficiency virus (HIV). The National 

Cancer Institute nominated AZT for toxicity and 

carcinogenicity studies because of the impending 

large-scale use of AZT in the treatment of adult 

patients with AIDS or AIDS-related complex. 

"-Interferon A/D, which displays antiviral activity in 

mice, is a hybrid molecule composed of the 

N-terminal portion of human "-interferon A and the 

C-terminal portion of human "-interferon D. AZT 

and "-interferon A/D combination studies were 

conducted because in vitro studies of AZT and 

"-interferon have demonstrated that the combination 

is more effective in blocking HIV infection than either 

agent alone. Male and female B6C3F1 mice received

AZT (approximately 98% pure) in 0.5% aqueous 

methylcellulose by gavage for 14 weeks or 2 years. 

In addition, male and female B6C3F1 mice received 

"-interferon A or "-interferon A/D by subcutaneous 

injection for 2 years, and male and female B6C3F1 

mice received AZT in 0.5% aqueous methylcellulose 

by gavage in combination with "-interferon A/D by 

subcutaneous injection for 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, 

cultured Chinese hamster ovary cells, mouse bone 

marrow erythrocytes, and mouse peripheral blood 

erythrocytes. 

14-WEEK AZT STUDY 

Groups of 10 male and 10 female mice received AZT 

in 0.5% methylcellulose by gavage at doses of 0, 50, 

100, 200, 800, or 2,000 mg/kg daily for 14 weeks. 

Additional groups of 10 male and 10 female mice 

received AZT in 0.5% methylcellulose by gavage at 

doses of 0, 100, 800, or 2,000 mg/kg daily for 

14 weeks and then were held without treatment for an 

additional 4 weeks before necropsy. One female 

receiving 100 mg/kg and two females receiving 
8 AZT and AZT/"-Interferon A/D, NTP TR 469 

200 mg/kg died during week 1 as a result of gavage 

trauma; one female receiving 2,000 mg/kg also died 

prior to the end of the 14-week dosing period. One 

female receiving 2,000 mg/kg in the recovery study 

also died from gavage trauma during week 1. The 

final mean body weights of dosed mice were similar 

to those of the vehicle control groups at the end of the 

dosing period and at the end of the recovery period. 

Female mice receiving 200, 800, or 2,000 mg/kg 

gained less weight than the vehicle controls during the 

14-week dosing period. 

Exposure to AZT was toxic to the bone marrow, 

resulting in significant changes in the peripheral blood 

(decreased hematocrit values, erythrocyte counts, and 

hemoglobin concentrations, and increased mean cell 

volume and mean cell hemoglobin) and bone marrow 

(erythroid hypoplasia) characteristic of a dose- and 

time-dependent, minimal to moderate, poorly regenerative macrocytic anemia. At the end of the 4-week 

recovery period, the hematology parameters had 

returned to normal, indicating that the hematotoxicity 

was reversible. 

2-YEAR STUDIES 

AZT 

Groups of 95 male and 95 female mice received AZT 

in 0.5% methylcellulose by gavage at daily doses of 

0, 30, 60, or 120 mg/kg body weight, administered as 

two equal doses at least 6 hours apart, 5 days per 

week for 105 weeks. Each group of 95 animals was 

composed of a core group of 50 animals for 

evaluation of carcinogenic response, a group of 

30 animals for evaluation of hematology and bone 

marrow cellularity, and a group of 15 animals from 

which blood was drawn for determination of plasma 

AZT concentrations at week 54. 

"-Interferon A/D 

and AZT/"-Interferon A/D Studies 

Groups of 80 male and 80 female mice received AZT 

in 0.5% aqueous methylcellulose by gavage at daily 

doses of 0, 30, 60, or 120 mg/kg body weight, given 

in two equal doses, 5 days per week for 105 weeks. 

Those groups receiving AZT also received subcutaneous injections of 500 or 5,000 U "-interferon 

A/D three times per week for 105 weeks. Additional 

groups of 80 male and 80 female mice received 

subcutaneous injections of the vehicle, 500 U 

"-interferon A/D, 5,000 U "-interferon A/D, or 

5,000 U "-interferon A, three times per week for 

105 weeks. 

Each group of 80 animals was composed of a core 

group of 50 animals for evaluation of carcinogenic 

response and a group of 30 animals for evaluation of 

hematology and bone marrow cellularity. 

Because of the large number of animals involved, the 

2-year studies were started in four phases and, for 

clarity, are presented as follows: the AZT study, the 

"-interferon A/D study, the AZT/500 U "-interferon 

A/D study, and the AZT/5,000 U "-interferon A/D 

study. 
AZT and AZT/"-Interferon A/D, NTP TR 469 9 

Design of the 2-Year AZT, AZT/"-Interferon A/D, and "-Interferon A/D Studies 

AZT Dose AZT Study "-Interferon A/D 

AZT/500 U 

Study 

"-Interferon A/D 

AZT/5,000 U 

Study 

5,000 U "-Interferon A 

"-Interferon A/D or 

Study 

500 or 5,000 U 

Vehicle Control 95 male and 

95 female micea 80 male and 80 female miceb 

80 male and 

80 female miceb 

80 male and 

80 female miceb 

30 mg/kg AZT 95 male and 

95 female mice 

80 male and 

80 female mice 

80 male and 

80 female mice 

None 

60 mg/kg AZT 95 male and 

95 female mice 

80 male and 

80 female mice 

80 male and 

80 female mice 

None 

120 mg/kg AZT 95 male and 

95 female mice 

80 male and 

80 female mice 

80 male and 

80 female mice 

None 

a For the AZT study, there were 95 male and 95 female mice; these were divided into 50 males and 50 females in the core groups, 30 males 

and 30 females in the clinical pathology groups (hematology and bone marrow analyses only), and 15 males and 15 females for plasma AZT 

concentration determinations. 

b	 For the "-interferon A/D study and the AZT/"-interferon A/D studies, there were 80 male and 80 female mice for each study; these were 

divided into 50 males and 50 females in the core groups and 30 males and 30 females in the clinical pathology groups (hematology and bone 

marrow analyses only). 

Survival and Body Weights 

Survival and mean body weights of mice exposed to 

AZT, "-interferon A, "-interferon A/D, or AZT plus 

"-interferon A/D were generally similar to those of 

the vehicle control groups. 

Hematology and Bone Marrow Analyses 

All groups of male and female mice receiving AZT 

exhibited changes in peripheral blood and bone 

marrow characteristic of a dose- and time-dependent, 

minimal to mild, macrocytic, nonresponsive anemia. 

In females, these changes were evident throughout the 

study. In males, the macrocytic anemia had resolved 

by week 80 in the 30 mg/kg group; at study termination erythrocyte macrocytosis was present only in 

males receiving 60 or 120 mg/kg AZT or AZT plus 

"-interferon A/D. There were no treatment-related 

alterations in hematology or bone marrow parameters 

in groups that received only "-interferon A or A/D. 

Pathology Findings 

Incidences of squamous cell carcinoma and squamous 

cell papilloma or carcinoma (combined) of the vagina 

occurred with a positive trend and were significantly 

increased in groups of female mice receiving 60 or 

120 mg/kg AZT alone or in combination with 

"-interferon A/D. Epithelial hyperplasia was 

observed in all dosed groups of females, and the 

incidence was significantly increased in the 120 mg/kg 

AZT group. 

Three renal tubule adenomas and one renal tubule 

carcinoma were observed in male mice receiving 

120 mg/kg AZT; the combined incidence in this group 

exceeded the range in historical controls. A renal 

tubule adenoma was observed in one male receiving 

60 mg AZT/kg and 500 U "-interferon A/D; however, none were observed in other groups. Evaluation 

of step sections revealed a few more renal tubule 

hyperplasias but no additional neoplasms. 

The incidence of harderian gland adenoma was increased in male mice receiving 120 mg/kg AZT and 

exceeded the range in historical controls. Harderian 

gland neoplasms were observed in other groups but 

did not follow a treatment-related pattern. 
 

10 AZT and AZT/"-Interferon A/D, NTP TR 469 

Overall Incidences of Vaginal Neoplasms and Hyperplasia of the Vaginal Epithelium in Female Mice 

in the 2-Year Gavage Studies of AZT and AZT/"-Interferon A/Da 

Vehicle Control 30 mg AZT/kg 60 mg AZT/kg 120 mg AZT/kg 

AZT alone 2/197 (1%)b 

1/197 

0/49 (0%) 

3/49 

5/45 (11%) 

4/45 

11/49 (22%) 

11/49 

500 U "-Interferon A/D 0/49 (0%) 

0/49 

0/44 (0%) 

4/44 

5/48 (10%) 

8/48 

6/48 (13%) 

12/48 

5,000 U "-Interferon A/D 1/50 (2%) 

1/50 

1/48 (2%) 

4/48 

5/48 (10%) 

8/48 

4/50 (8%) 

15/50 

a Data are presented as number of vaginal neoplasms/number of animals microscopically examined (first line) and number of vaginal
 

hyperplasias/number of animals microscopically examined (second line) b	 Combined incidences of controls from the AZT alone study and the AZT/"-interferon A/D studies; incidences in the vehicle control group 

from the AZT alone study are 0/50 (0%) (neoplasms) and 0/50 (hyperplasia) 

Overall Incidence of Harderian Gland Neoplasms in Male Mice in the 2-Year Gavage Studies 

of AZT and AZT/"-Interferon A/Da 

Vehicle Control 30 mg AZT/kg 60 mg AZT/kg 120 mg AZT/kg 

AZT alone 13/200 (6%)b 5/50 (10%) 2/50 (4%) 10/50 (20%) 

500 U "-Interferon A/D 3/50 (6%) 3/50 (6%) 1/50 (2%) 4/50 (8%) 

5,000 U "-Interferon A/D 3/50 (6%) 9/50 (18%) 4/50 (8%) 4/50 (8%) 

a Data are presented as number of harderian gland neoplasms/number of animals necropsied b	 Combined incidences of controls from the AZT alone study and the AZT/"-interferon A/D studies; incidence in the vehicle control group 

from the AZT alone study is 3/50 (6%) 

Male mice had a pattern of nonneoplastic liver lesions 

along with silver-staining helical organisms within the 

liver consistent with an infection with Helicobacter 

hepaticus. An organism compatible with H. hepaticus 

was confirmed by polymerase chain reactionrestriction fragment length polymorphism-based 

assays. Detection of dose-related differences in neoplasm incidences in these studies was not considered 

to have been significantly impacted by the infection 

with H. hepaticus or its associated hepatitis. 

GENETIC TOXICOLOGY 

AZT is mutagenic in vitro and in vivo. It induced 

gene mutations in Salmonella typhimurium strain 

TA102, with and without S9; no increases in mutations were noted in the other tested strains of 

S. typhimurium. AZT induced sister chromatid 

exchanges, but not chromosomal aberrations, in 

cultured Chinese hamster ovary cells, with and without S9. In vivo studies with male mice administered 

AZT by gavage showed highly significant increases in 

micronucleated erythrocytes in bone marrow and 

peripheral blood after exposure periods that ranged 

from 72 hours to 14 weeks. 

CONCLUSIONS 

Under the conditions of these 2-year gavage studies 

there was equivocal evidence of carcinogenic activity* 

of AZT in male mice based on increased incidences of 

renal tubule and harderian gland neoplasms in groups 
__________ 

AZT and AZT/"-Interferon A/D, NTP TR 469 11 

receiving AZT alone. There was clear evidence of Treatment with AZT alone and AZT in combination 

carcinogenic activity of AZT in female mice based on with "-interferon A/D resulted in increased incidences 

increased incidences of squamous cell neoplasms of of epithelial hyperplasia of the vagina in all dosed 

the vagina in groups that received AZT alone or in groups of females. 

combination with "-interferon A/D. 

Hematotoxicity occurred in all groups that received 

AZT. 

* Explanation of Levels of Evidence of Carcinogenic Activity is on page 14. A summary of the Technical Reports Review Subcommittee 

comments and the public discussion on this Technical Report appears on page 16. 
12 AZT and AZT/"-Interferon A/D, NTP TR 469 

Summary of the 2-Year Carcinogenesis and Genetic Toxicology Studies of AZT and AZT/"-Interferon A/D 

in Mice 

AZT "-Interferon A/D AZT/500 U 

"-Interferon A/D 

AZT/5,000 U 

"-Interferon A/D 

Doses 0, 30, 60, or 120 mg 

AZT/kg body weight in 

0.5% methylcellulose by 

gavage, given 5 days per 

week in two equal doses of 

0, 15, 30, or 60 mg/kg per 

dose 

0, 500, or 5,000 U 

"-interferon A/D 

or 5000 U "-interferon A 

administered 

subcutaneously three 

times per week 

0, 30, 60, or 120 mg 0, 30, 60, or 120 mg 

AZT/kg body weight in AZT/kg body weight in 

0.5% methylcellulose by 0.5% methylcellulose by 

gavage, given 5 days per gavage, given 5 days per 

week in two equal doses week in two equal doses of 

of 0, 15, 30, or 60 mg/kg 0, 15, 30, or 60 mg/kg per 

per dose. Dosed groups dose. Dosed groups also 

also received 500 U received 5,000 U 

"-interferon A/D "-interferon A/D 

administered subcutaneously administered subcutaneously 

three times per week. three times per week. 

Body weights Dosed groups similar to 

vehicle control groups 

Dosed groups generally 

similar to vehicle control 

Dosed groups similar to 

vehicle control groups 

Dosed groups similar to 

vehicle control groups 

groups 

2-Year survival 

rates 

Males Males 

32/50, 35/50, 29/50, 42/50 27/50, 28/50, 28/50 

Females Females 

Males Males 

36/50, 27/50, 38/50, 35/50 31/50, 35/50, 35/50, 34/50 

Females Females 

34/50, 39/50, 31/50, 31/50 25/50, 32/50, 25/50 33/50, 32/50, 32/50, 24/49 37/50, 38/50, 36/50, 32/50 

Nonneoplastic 

effects 

Females 

Vagina: epithelial 

hyperplasia (0/50, 3/49, 

2/45, 7/49); atypical 

hyperplasia (0/50, 0/49, 

2/45, 4/49) 

None Females 

Vagina: epithelial 

hyperplasia (0/49, 4/44, 

6/48, 11/48); atypical 

hyperplasia (0/49, 0/44, 

2/48, 1/48) 

Females 

Vagina: epithelial 

hyperplasia (1/50, 3/48, 

7/48, 12/50); atypical 

hyperplasia (0/50, 1/48, 

1/48, 3/50) 

Neoplastic effects Females 

Vagina: squamous cell 

carcinoma (0/50, 0/49, 

5/45, 9/49); squamous cell 

papilloma or carcinoma 

(0/50, 0/49, 5/45, 11/49) 

None Females 

Vagina: squamous cell 

carcinoma (0/49, 0/44, 

5/48, 6/48) 

Females 

Vagina: squamous cell 

carcinoma (0/50, 0/48, 5/48, 

4/50) 

Uncertain findings Males 

Kidney: renal tubule 

adenoma (0/50, 0/48, 0/49, 

3/50); renal tubule 

carcinoma (0/50, 0/48, 

0/49, 1/50) 

Harderian gland: adenoma 

(3/50, 2/50, 2/50, 10/50); 

adenoma or carcinoma 

None None None 

(3/50, 5/50, 2/50, 10/50) 
 

AZT and AZT/"-Interferon A/D, NTP TR 469 13 

Summary of the 2-Year Carcinogenesis and Genetic Toxicology Studies of AZT and AZT/"-Interferon A/D 

in Mice 

AZT/500 U AZT/5,000 U AZT "-Interferon A/D "-Interferon A/D "-Interferon A/D 

Level of evidence	 Males 

Equivocal evidence of carcinogenic Females activity Clear evidence 

Genetic toxicology 

Salmonella typhimurium gene mutations: 

Sister chromatid exchanges 

Cultured Chinese hamster ovary cells in vitro: 

Chromosomal aberrations 

Cultured Chinese hamster ovary cells in vitro: 

Micronucleated erythrocytes
 

Mouse bone marrow in vivo:
 

Mouse peripheral blood in vivo:
 

Positive in strain TA102 with and without S9; negative in strains TA97, TA98, TA100, 

TA104, and TA1535, with and without S9 

Positive with and without S9 

Negative with and without S9 

Positive 

Positive 
14 AZT and AZT/"-Interferon A/D, NTP TR 469 

EXPLANATION OF LEVELS OF EVIDENCE OF CARCINOGENIC ACTIVITY 

The National Toxicology Program describes the results of individual experiments on a chemical agent and notes the strength of the evidence for 

conclusions regarding each study. Negative results, in which the study animals do not have a greater incidence of neoplasia than control 

animals, do not necessarily mean that a chemical is not a carcinogen, inasmuch as the experiments are conducted under a limited set of 

conditions. Positive results demonstrate that a chemical is carcinogenic for laboratory animals under the conditions of the study and indicate that 

exposure to the chemical has the potential for hazard to humans. Other organizations, such as the International Agency for Research on Cancer, 

assign a strength of evidence for conclusions based on an examination of all available evidence, including animal studies such as those conducted 

by the NTP, epidemiologic studies, and estimates of exposure. Thus, the actual determination of risk to humans from chemicals found to be 

carcinogenic in laboratory animals requires a wider analysis that extends beyond the purview of these studies. 

Five categories of evidence of carcinogenic activity are used in the Technical Report series to summarize the strength of the evidence observed 

in each experiment: two categories for positive results (clear evidence and some evidence); one category for uncertain findings (equivocal 

evidence); one category for no observable effects (no evidence); and one category for experiments that cannot be evaluated because of major 

flaws (inadequate study). These categories of interpretative conclusions were first adopted in June 1983 and then revised in March 1986 for 

use in the Technical Report series to incorporate more specifically the concept of actual weight of evidence of carcinogenic activity. For each 

separate experiment (male rats, female rats, male mice, female mice), one of the following five categories is selected to describe the findings. 

These categories refer to the strength of the experimental evidence and not to potency or mechanism. 

•	 Clear evidence of carcinogenic activity is demonstrated by studies that are interpreted as showing a dose-related (i) increase of 

malignant neoplasms, (ii) increase of a combination of malignant and benign neoplasms, or (iii) marked increase of benign 

neoplasms if there is an indication from this or other studies of the ability of such tumors to progress to malignancy. 

•	 Some evidence of carcinogenic activity is demonstrated by studies that are interpreted as showing a chemical-related increased 

incidence of neoplasms (malignant, benign, or combined) in which the strength of the response is less than that required for clear 

evidence. 

•	 Equivocal evidence of carcinogenic activity is demonstrated by studies that are interpreted as showing a marginal increase of
 

neoplasms that may be chemical related.
 

•	 No evidence of carcinogenic activity is demonstrated by studies that are interpreted as showing no chemical-related increases in 

malignant or benign neoplasms. 

•	 Inadequate study of carcinogenic activity is demonstrated by studies that, because of major qualitative or quantitative limitations, 

cannot be interpreted as valid for showing either the presence or absence of carcinogenic activity. 

When a conclusion statement for a particular experiment is selected, consideration must be given to key factors that would extend the actual 

boundary of an individual category of evidence. Such consideration should allow for incorporation of scientific experience and current 

understanding of long-term carcinogenesis studies in laboratory animals, especially for those evaluations that may be on the borderline between 

two adjacent levels. These considerations should include: 

• adequacy of the experimental design and conduct;
 

• occurrence of common versus uncommon neoplasia;
 

•	 progression (or lack thereof) from benign to malignant neoplasia as well as from preneoplastic to neoplastic lesions; 

•	 some benign neoplasms have the capacity to regress but others (of the same morphologic type) progress. At present, it is 

impossible to identify the difference. Therefore, where progression is known to be a possibility, the most prudent course is to 

assume that benign neoplasms of those types have the potential to become malignant; 

•	 combining benign and malignant tumor incidence known or thought to represent stages of progression in the same organ or tissue; 

•	 latency in tumor induction; 

•	 multiplicity in site-specific neoplasia; 

•	 metastases; 

•	 supporting information from proliferative lesions (hyperplasia) in the same site of neoplasia or in other experiments (same lesion in 

another sex or species); 

•	 presence or absence of dose relationships; 

•	 statistical significance of the observed tumor increase; 

•	 concurrent control tumor incidence as well as the historical control rate and variability for a specific neoplasm; 

•	 survival-adjusted analyses and false positive or false negative concerns; 

•	 structure-activity correlations; and 

•	 in some cases, genetic toxicology. 
_________________ 

AZT and AZT/"-Interferon A/D, NTP TR 469 15 

NATIONAL TOXICOLOGY PROGRAM BOARD OF SCIENTIFIC COUNSELORS
 

TECHNICAL REPORTS REVIEW SUBCOMMITTEE
 

The members of the Technical Reports Review Subcommittee who evaluated the draft NTP Technical Report on AZT and AZT/"-interferon 

A/D on 11 December 1996 are listed below. Subcommittee members serve as independent scientists, not as representatives of any institution, 

company, or governmental agency. In this capacity, subcommittee members have five major responsibilities in reviewing the NTP studies: 

• to ascertain that all relevant literature data have been adequately cited and interpreted, 

• to determine if the design and conditions of the NTP studies were appropriate, 

• to ensure that the Technical Report presents the experimental results and conclusions fully and clearly, 

• to judge the significance of the experimental results by scientific criteria, and 

• to assess the evaluation of the evidence of carcinogenic activity and other observed toxic responses. 

Gary P. Carlson, Ph.D., Chairperson Irma Russo, M.D. 

School of Health Sciences Fox Chase Cancer Center 

Purdue University Philadelphia, PA 

West Lafayette, IN 

Louise Ryan, Ph.D.* Arnold L. Brown, M.D. Division of Biostatistics 

University of Wisconsin Medical School Dana-Farber Cancer Institute 

Madison, WI Boston, MA 

Thomas L. Goldsworthy, Ph.D. Robert E. Taylor, M.D., Ph.D. 

Department of Experimental Pathology and Toxicology Department of Pharmacology 

Chemical Industry Institute of Toxicology Howard University College of Medicine 

Research Triangle Park, NC Washington, DC 

Robert LeBoeuf, Ph.D., Principal Reviewer Frederick L. Tyson, M.D., Ph.D., Principal Reviewer 

Corporate Professional and Regulatory Services St. Mary’s Hospital and Medical Center 

Human Safety Department Cancer Research Institute 

The Procter & Gamble Company Grand Junction, CO 

Cincinnati, OH 

Jerrold M. Ward, D.V.M., Ph.D. 

Janardan K. Reddy, M.D., Principal Reviewer National Cancer Institute 

Department of Pathology Frederick, MD 

Northwestern University Medical School 

Chicago, IL 

* Did not attend 
16 AZT and AZT/"-Interferon A/D, NTP TR 469 

SUMMARY OF TECHNICAL REPORTS REVIEW SUBCOMMITTEE COMMENTS
 

On 11 December 1996, the draft Technical Report on 

the toxicology and carcinogenesis studies of 3N-azido3N-deoxythymidine (AZT) and AZT/"-interferon A/D 

received public review by the National Toxicology 

Program’s Board of Scientific Counselors’ Technical 

Reports Review Subcommittee. The review meeting 

was held at the National Institute of Environmental 

Health Sciences, Research Triangle Park, NC. 

Dr. R.D. Irwin, NIEHS, introduced the toxicology 

and carcinogenesis studies of AZT and AZT/ 

"-interferon A/D by discussing the uses of the 

chemicals and rationale for study, describing the 

experimental design (including a recovery group of 

mice to assess reversibility of bone marrow changes), 

reporting on the lack of survival and body weight 

effects, and commenting on treatment-related neoplasms and nonneoplastic lesions in mice. The proposed conclusions for the 2-year studies in mice were 

equivocal evidence of carcinogenic activity of AZT in 

male mice and clear evidence of carcinogenic activity 

of AZT in female mice. 

Dr. LeBoeuf, a principal reviewer, agreed with the 

proposed conclusions. He noted the presence of 

Helicobacter hepaticus as a potential confounding 

factor for interpretation of liver lesions, but agreed 

that in this case it would not have an impact on the 

level of evidence for males or females. 

Dr. Reddy, the second principal reviewer, agreed with 

the proposed conclusions. He asked why the studies 

were not also conducted in rats and whether there 

were any case reports indicating an increase in vaginal 

neoplasms in human females. Dr. Irwin responded 

that Burroughs Wellcome had conducted asatisfactory 

study in rats. Dr. K.M. Ayers, Glaxo Wellcome, 

reported that the findings have been cited in the 

Physicians Desk Reference since about 1990. Dr. 

Irwin said there are no reports in the literature of 

genital neoplasms associated with the use of AZT in 

human females. Dr. Reddy said that, nonetheless, the 

findings could raise concerns because of the genital 

papillomas and warts reported in human papilloma 

virus infected HIV-positive men and women. 

Dr. Tyson, the third principal reviewer, agreed with 

the proposed conclusions. He asked about the rationale for the strain of mice used and thought it would 

have been of interest to have used a strain of immunocompromised mice. Dr. Tyson commented that useful 

insights might have been gained from looking for 

molecular markers found in human vaginal tumors, 

such as activated oncogenes or certain papilloma 

viruses. Dr. Irwin said that with the complexity of 

the study, it was preferred to use the B6C3F model 1 

for which there was a large historical database. 

Dr. Goldsworthy asked whether higher incidences of 

hepatoblastoma in mice might be associated with 

H. hepaticus. Dr. J.R. Hailey, NIEHS, said that NTP 

had seen hepatoblastomas more frequently in recent 

studies as part of what seems to be a progression of 

that lesion. 

Dr. LeBoeuf moved that the Technical Report on 

AZT and AZT/"-interferon A/D be accepted with the 

revisions discussed and the conclusions as written for 

male mice, equivocal evidence of carcinogenic 

activity, and for female mice, clear evidence of 

carcinogenic activity. Dr. Reddy seconded the 

motion, which was accepted unanimously with eight 

votes. 
17 

INTRODUCTION
 

HN 

N 

O 

CH3 

O 

O 

HOCH2 

N3 

3N-AZIDO-3N-DEOXYTHYMIDINE 

CAS No. 30516-87-1 

Chemical Formula: C 10 13 5 4 H N O Molecular Weight: 267.24 

Synonyms: 

Trade name: 

AZT; 3N-azido-2N,3N-dideoxythymidine; azidodeoxythymidine; azidothymidine; 3N-azidothymidine; 3N-deoxy-3N-azidothymidine; 

3N-deoxy-(8CI) (9CI); BW A509U; Compound S; ZDV; zidovudine 

Retrovir® 

CHEMICAL AND PHYSICAL PROPERTIES 

AZT 

3N-Azido-3N-deoxythymidine (AZT) is a dideoxynucleoside of thymine and structural analogue of 

2N-deoxythymidine (dT), and is the most widely used 

and evaluated chemotherapeutic agent for the 

treatment of persons with acquired immune deficiency 

syndrome (AIDS) and persons seropositive for human 

immunodeficiency virus (HIV). AZT is a white to 

off-white, odorless, crystalline solid which is 

moderately soluble in water (20 mg/mL) and alcohol 

(71 mg/mL) at 25 C. The oral solution of AZT, 

which contains 50 mg per 5 mL, is colorless to pale 

yellow and has a pH of 3 to 4. When reconstituted 

with water for injection, AZT solutions containing 

10 mg AZT/mL have a pH of approximately 5.5 

(AHFS, 1997). 

Interferon 

Interferon is the general name given to a family of 

cytokines best known for their immunomodulatory 

function and in particular, their unique ability to 

interfere with viral replication. Four groups of 

interferons (", $, (, and T) have been identified in 

humans and other mammalian species based on cell of 

origin, antigenic differences, and amino acid sequence 

homology. Most recently, classification of the 

various types of interferons has been based on 

nucleotide sequence homology within coding 

sequences. Based on structural and functional 

similarities, "-, $-, and T-interferons are often 

collectively referred to as Type I interferons, whereas 

(-interferon is referred to as Type II interferon 

(reviewed in De Maeyer and De Maeyer-Guignard, 

1998). 
 

18 AZT and AZT/"-Interferon A/D, NTP TR 469 

In humans, "-interferon is encoded by a family of 

approximately 18 nonallelic genes located on the short 

arm of chromosome 9. The primary translation 

products of these genes contain 189 amino acids from 

which a 23-amino-acid N-terminal leader sequence is 

cleaved posttranslationally to yield a family of 

"-interferon proteins containing 165 or 166 amino 

acids. Also present at this locus on chromosome 9 is 

the single-copy human $-interferon gene, the primary 

translation product of which is similarly processed to 

a 166-amino-acid protein that is glycosylated at an 

asparagine residue (De Maeyer and De MaeyerGuignard, 1998). The human T-interferon gene 

family consists of one functional gene that encodes 

T1-interferon and four pseudogenes (Hauptmann and 

Swetly, 1985; Adolf et al., 1991). Mature 

T1-interferon contains 170 or 172 amino acids and, 

like $-interferon, is glycosylated at a single asparagine 

residue. However, unlike other type I interferons, 

T1-interferon is heterogeneous at its N-terminal end 

due to the existence of two signal peptidase cleavage 

sites (Adolf et al., 1991). 

The human "-interferon proteins exhibit approximately 80% to 85% sequence homology with one 

another, while $- and T1-interferon are approximately 

30% to 40% homologous with "-interferon. By 

contrast, the mature 166-amino-acid (-interferon 

exhibits no obvious sequence homology to "-, $-, or 

T1-interferon, and the single-copy human (-interferon 

gene is located at a different genetic locus. 

PRODUCTION, USE, 

AND HUMAN EXPOSURE 

AZT 

AZT was first synthesized by Horwitz et al. (1964), 

and it was subsequently reported to inhibit HIV 

replication in vitro at concentrations ranging from 

50 to 500 nmol/L by Mitsuya et al. (1985). Clinical 

activity for the treatment of AIDS was first reported 

by Yarchoan et al. (1986), and the drug has been 

commercially developed by Burroughs Wellcome 

Company (Research Triangle Park, NC). AZT was 

approved by the Food and Drug Administration 

for the treatment of adult patients with AIDS or 

advanced AIDS-related complex in March 1987 

(Anonymous, 1987). 

AZT is available in capsules or syrup for oral administration and in formulations suitable for intravenous 

infusion. A typical therapeutic regimen involving oral 

administration consists of 100 mg AZT every 4 hours, 

which, for a 60-kg individual, equates to 10 mg/kg 

per day (AHFS, 1997). 

Interferon 

"-, $-, and T-Interferons are induced in many different types of cells, but (-interferon is produced only 

by activated T-lymphocytes and natural killer (NK) 

cells (Capon et al., 1985). Although the steps 

involved in the induction of interferon synthesis are 

not well understood, in most responses the synthesis 

of Type I interferons is coordinately induced, and the 

resulting “interferon” is a mixture of ", $, and T 

subforms. However, cell- and tissue-selective 

induction of individual subforms is also observed. 

The antiproliferative, antiviral, and immunomodulatory activities of the interferons have stimulated interest in the use of these agents for the treatment of a 

number of disorders including neoplastic as well as 

viral and microbial diseases. The constitutive level of 

interferons in normal blood is very low, although synthesis of "-, $-, and T-interferons is induced by exposure to numerous infectious agents including bacteria, 

Rickettsia, Mycoplasma, protozoa, and viruses, as 

well as by double-stranded RNA and the synthetic 

polyribonucleotide poly (rI:rC). Due to the therapeutic potential of the interferons, the coding 

sequences of several human interferon genes have 

been cloned in bacteria, and this has provided a 

high-volume source of pure recombinant human 

interferons (Pestka et al., 1987). Bacterial clones of 

several hybrid human interferons have also been 

prepared and evaluated for antiviral activity. Although interferons exhibit strong species specificity in 

their activity, a few of the human hybrids were found 

to induce antiviral activity in mice (Pestka, 1983; 

Pestka et al., 1987). In the studies presented in this 

Technical Report, a hybrid recombinant human 

interferon that induces substantial antiviral activity in 

mice was used. This hybrid is designated 

rHIFN" A/D (BglII) and it is obtained from a clone

containing the 5N end of the "-interferon A coding 

sequence ligated to the "-interferon D coding 

sequence from which the 5N end had been cut. The 

presence of a BglII restriction endonuclease site in the 
AZT and AZT/"-Interferon A/D, NTP TR 469 19 

codingsequencesof "-interferon A and "-interferon D 

genes allowed the two individual sequences to be 

cleaved and the corresponding pieces ligated to form 

the hybrid coding sequence. Thus, the first 62 amino 

acids of rHIFN" A/D are from the N-terminal portion

of human "-interferon A, and amino acids 64 to 166 

are from human "-interferon D (Pestka, 1983; 

Horisberger and Di Marco, 1995). 

ABSORPTION, DISTRIBUTION, 

METABOLISM, AND EXCRETION 

AZT 

Following oral administration AZT is rapidly 

absorbed, and after oral or intravenous administration 

it is rapidly distributed (Table 1). Elimination is also 

rapid, with essentially all parent drug and its metabTABLE 1 

AZT Pharmacokinetic Parametersa 

olites being completely excreted within 24 hours. 

However, there are significant interspecies differences 

in the extent to which the parent compound is metabolized (Table 2). In humans and monkeys, the 

majority of an administered dose is converted to the 

5N-O-glucuronide (GAZT) and eliminated in urine 

along with unmetabolized parent drug and a minor 

metabolite, 3N-amino-2N,3N-dideoxythymidine (AMT), 

formed by reduction of the 3N-azido group of AZT. 

However, in rats and other rodents, the majority of 

absorbed AZT is eliminated in urine as the parent 

compound with relatively little conversion to the 

glucuronide or to AMT (Table 2). GAMT, the glucuronide of AMT, has been reported to be a minor urinary metabolite in monkeys and a minor biliary 

metabolite in humans, but GAMT has not been 

identified in rats (de Miranda et al., 1990). 

Species Route Dose Cmax 

(μg/mL) Tmax t1⁄2 Reference 

Human oral 400 mg 1.9 0.93 ± 0.42 hrs 1.0 ± 0.8 hrs Child et al., 1991 

oral 200 mg 1.07 ± 0.3 0.65 ± 0.2 hrs 1.0 ± 0.5 hrs Singlas et al., 1989 

oral 200 mg 1.07 ± 0.3 0.6 ± 0.2 hrs 1.0 ± 0.4 hrs Taburet et al., 1990 

intravenous 2.5 mg/kg 1.31 ± 0.3 1.2 ± 0.03 hrs Stagg et al., 1992 

Monkey, rhesus subcutaneous 33.3 mg/kg 8.9 ± 1.4 0.7 ± 0.3 hrs 0.8 ± 0.1 hrs Cretton et al., 1991a 

Rat, F344 intravenous 40 mg/kg 0.47 ± 0.03 hrs Wientjes and Au, 1992 

Rat, Sprague-Dawley intravenous 10 mg/kg 

50 mg/kg 

100 mg/kg 

250 mg/kg 

0.76 ± 0.35 hrs 

1.31 ± 1.05 hrs 

2.03 ± 1.67 hrs 

1.58 ± 0.81 hrs 

Patel et al., 1989 

Mouse, B6C3F1 oral 15 mg/kg 

30 mg/kg

60 mg/kg

9.1 ± 1.5 

18.9 ± 0.5 

40.3 ± 7.2 

18.3 ± 2.9 min

21.7 ± 7.6 min

15.0 ± 5.0 min

 18.5 min 

16.5 min 

21.9 min 

Trang et al., 1993 

Mouse, NIH-Swiss intravenous 250 mg/kg 0.78 hrs Doshi et al., 1989 

a When available, data are presented as mean ± standard deviation. 
20 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE 2 

AZT Metabolitesa 

Species 

Urinary Metabolites (% Dose) Bile (B) or Fecal (F) 

Metabolites (% Dose) 

Reference 

AZT GAZT AMT GAMT GAZT AMT GAMT 

Human 

Human

Human 

Monkey, 

rhesus 

Rat, Long 

Evans 

Rat, 

SpragueDawley 

13 86 

16.7 ± 2.1 74.7 ± 6.5 2.0 ± 0.5 

8.1 ± 2.4 61.5 ± 3.4 

26.8 ± 5.2 59.6 ± 5.3 1.4 ± 0.6 0.4 ± 0.3 

87.7 6.1 0.9 

79.0 ± 5.7 0.8 ± 0.7 

Trace (B) 

5.1 (B) 15 (F) 

Good et al., 1990 

Stagg et al., 1992 

Singlas et al., 1989 

Cretton et al., 1991a 

de Miranda et al., 1990 

Mays et al., 1991 

a When available, data are presented as mean ± standard deviation. 

In suspensions of freshly isolated rat hepatocytes, 

AZT is extensively converted to GAZT with AMT 

and GAMT formed in lesser amounts. AMT is not a 

substrate for UDPGT, which indicates that GAMT is 

formed by reduction of the 3N-azido group of GAZT 

rather than by glucuronidation of AMT (Cretton 

et al., 1991b). In microsomes prepared from human 

liver, the rate of AMT formation is proportional to 

cytochrome P450 content and it is enhanced up to fivefold by the addition of NADPH, FAD, and FMN. 

AMT formation is abolished by prior incubation with 

carbon monoxide (Placidi et al., 1993). Somewhat 

different results were obtained by Nicolas et al. 

(1995) in cultured hepatocytes from rats, dogs, 

monkeys, and humans. In these systems, AZT is converted primarily to GAZT by hepatocytes from 

humans (63%-73%) and monkeys (63%-73%), whereas unchanged parent is predominant in rat (86%-90%) 

or dog (95%) hepatocyte cultures. AMT is a minor 

metabolite in cultured hepatocytes from all species and 

GAMT is not detected in cultured hepatocytes. 

Interferon 

The disposition and pharmacokinetics of recombinant 

human interferons have been evaluated in several 

species. Following intravenous administration to humans, dogs, monkeys, rats, and mice, interferons are 

rapidly cleared from blood regardless of the type, 

subtype, or species of origin (Greig et al., 1988; 

Greischel et al., 1988; Lave et al., 1995). However, 

in homologous species or in nonhomologous species 

in which a particular type or subtype of interferon 

exhibits biological activity, clearance is slower due to 

interaction with cells in the blood (Johns et al., 1990). 

Distribution to tissues also occurs rapidly, with the 

greatest concentration of material present in the liver 

and kidneys 30 to 60 minutes after administration 

(Rosenberg et al., 1985; Greig et al., 1988; Wills, 

1990; Kerry et al., 1993). The primary route of excretion is via the kidney, where interferons are filtered 

through the glomerulus, reabsorbed, and degraded by 

tubular epithelial cells (Bocci et al., 1982; Rosenberg 

et al., 1985). Since the products of interferon degradation are amino acids which reenter the blood and 

are reused, very few degradation products are 

excreted in urine. 

PHARMACOLOGY 

AZT 

The antiviral activity of AZT depends on its conversion to a nucleotide triphosphate (3N-azido2N,3N-dideoxythymidine triphosphate; AZTTP). AZT 

enters mammalian cells by nonfacilitated diffusion 

(Zimmerman et al., 1987) and it is then phosphorylated in successive reactions catalyzed by thymidine 
 

AZT and AZT/"-Interferon A/D, NTP TR 469 21 

kinase, thymidylate kinase, and nucleoside diphosphokinase. The resulting nucleoside triphosphate, 

AZTTP, is a substrate for HIV reverse transcriptase 

and a competitive inhibitor of dTTP. Because the 3N 

position of AZT is blocked with an azido group, 

incorporation of AZTTP into a growing polynucleotide chain (e.g., cDNA) terminates elongation 

at that position. Thus AZT intervenes at a relatively 

early stage of the viral replication cycle. AZTTP is 

also a substrate for cellular DNA polymerases; 

however, the Ki and Km of AZTTP for HIV reverse 

transcriptase are lower than for cellular DNA polymerases. Accordingly, AZTTP inhibits viral replication at doses lower than those at which it is an 

efficient substrate for the cellular DNA polymerases 

(Furman et al., 1986; Ono, 1989; Huang et al., 1990; 

Parker et al., 1991). 

Interferon 

Although "-, $-, and T-interferons are induced in 

many different types of cells, they all bind to the same 

(Type I) receptor on target cells. In contrast, 

(-interferon is produced only by activated T 

lymphocytes and NK cells, and it acts via a 

different (Type II) receptor on target cells (Capon 

et al., 1985; De Maeyer and De Maeyer-Guignard, 

1998). Type I interferons act locally as autocrine or 

paracrine mediators and represent a first line of 

defense that is active against invading organisms prior 

to any significant response by the immune system 

((-interferon is not produced until T cells have been 

activated by antigen exposure, and (-interferon is 

involved primarily in activation of immune reactions). 

The antiviral activity of "-, $-, or T-interferon is initiated by and requires binding of these Type I interferons to the Type I receptor on target cells; productive receptor occupancy results in activation of the 

JAK-STAT signal transduction pathway and leads to 

the transcription of genes whose promoters contain 

interferon response sequences (Müller et al., 1994; 

David, 1995; Hwang et al., 1995). The products of 

these genes are responsible for the observed antiviral 

activity of Type I interferons. Details of this process 

and the identity and function of its various molecular 

components are being actively investigated, and the 

subject has recently been reviewed (Schindler and 

Darnell, 1995). 

TOXICITY 

AZT 

Exposure to AZT results in myelosuppression and 

anemia in humans and experimental animals. In humans, this toxicity limits the useful therapeutic dose 

range of AZT (Fischl, 1989; Pluda et al., 1991; 

Balzarini, 1994). The primary target of AZT toxicity 

is the hematopoietic system of the bone marrow; 

in vitro coculture studies have demonstrated that AZT 

is cytotoxic to human and murine hematopoietic 

progenitor cells including colony forming units CFUGEMM, CFU-GM, CFU-E, and CFU-Meg 

(Sommadossi et al., 1987; Dainiak et al., 1988; 

Gallicchio et al., 1989). In cultures of human bone 

marrow cells, the extent of incorporation of AZTTP 

into cellular DNA and the growth inhibition of human 

clonal peripheral blood mononuclear cells have 

been correlated (Sommadossi and Carlisle, 1987; 

Sommadossi et al., 1989). In human erythroid K-562 

leukemia cells induced to differentiate by butyric acid 

treatment, AZT selectively reduced the steady-state 

level of globin mRNA (Weidner and Sommadossi, 

1990). Neither the kinetics of induction nor the 

steady-state mRNA levels of other components of the 

heme biosynthetic pathway were altered, including 

erythroid-specific isozymes of aminolevulinate 

synthase and porphobilinogen deaminase (Fowler 

et al., 1995). These results suggest a specific effect 

on transcription of the globin gene in erythroid cells. 

Another prominent dose-limiting toxicity observed 

primarily in patients undergoing long-term AZT 

therapy is a toxic mitochondrial myopathy (Dalakas 

et al., 1990). Clinical symptoms include myalgia, 

muscle weakness, and elevated levels of creatinine 

kinase in serum. These symptoms correlate with the 

presence in muscle biopsies of abnormal mitochondria 

containing paracrystalline inclusions. Human muscle 

myotubes grown in tissue culture exposed to AZT for 

9 days exhibited increased numbers of mitochondria 

as well as enlarged mitochondria with abnormal 

cristae and electron-dense deposits in the matrix 

(Lamperth et al., 1991). 

Biochemically and morphologically similar changes 

are present in rats exposed to AZT, which exhibit 

enlarged mitochondria with disorganized or absent 

cristae in skeletal and cardiac muscle (Lamperth 
22 AZT and AZT/"-Interferon A/D, NTP TR 469 

et al., 1991; Lewis et al., 1992). These changes 

correlate with impaired function of the electrontransport chain in skeletal muscle mitochondria 

(Lamperth et al., 1991). In Sprague-Dawley rats 

administered 1 mg/mL AZT in drinking water for 

35 days, decreases in mitochondrial DNA, RNA, and 

protein synthesis were observed in skeletal muscle 

mitochondria (Lewis et al., 1992). AZTTP is an 

inhibitor and alternate substrate for mitochondrial 

DNA polymerase ( from both skeletal and cardiac 

muscle (Simpson et al., 1989; Lewis et al., 1994), 

and therefore it is likely that AZT is acting as an 

inhibitor and chain terminator, disrupting 

mitochondrial DNA synthesis. 

Interferon 

Humans administered type I interferons often experience a variety of toxic responses (Fent and Zbinden, 

1988). The most frequently described are flu-like 

symptoms including fever, tachycardia, headache, 

myalgia, fatigue, and often nausea and vomiting. 

Leukopenia, neutropenia, and particularly with 

"-interferon, thrombocytopenia and elevated amino 

peptidase and transaminase levels in serum are also 

frequently observed. These effects are typically dose 

related and readily reverse upon discontinuation of 

treatment (Spiegel, 1987). 

Pure animal interferons are generally unavailable and 

this has limited the types of toxicology studies that 

have been done. More effort has been directed at 

cloning human interferon genes. For this reason, the 

toxicology of the recombinant human hybrid interferon "-interferon A/D, which is active in mice and is 

available in pure form, has been evaluated in a few 

relevant studies. Rosenthal et al. (1990) administered 

0, 1,000, 10,000, or 100,000 U "-interferon A/D 

per day intraperitoneally to female C57Bl/6N mice 

for 10 days. Spleen weights were significantly 

increased at all doses, and thymus weights were 

decreased in the groups receiving 10,000 or 

100,000 U. Many of the observed responses were 

similar to those observed in humans undergoing 

interferon therapy, including anemia, leukopenia, 

thrombocytopenia, and elevation of serum 

transaminase activity. Dunn and Crnic (1993) 

administered daily intraperitoneal injections of 1,600 

U "-interferon A/D per g body weight to Balb/c mice 

and observed a depression in open field spontaneous 

motor activity and in swimming performance but no 

decrease in grip strength in treated animals. 

GENETIC TOXICITY 

AZT was reported to be weakly positive in the mouse 

lymphoma cell mutagenicity test (Ayers, 1988; Olin 

and Kastrup, 1995) and to induce transformation in 

cultured mammalian cells (Olin and Kastrup, 1995). 

Results of in vitro cytogenetic assays with mammalian 

cells showed that AZT induced sister chromatid 

exchanges, chromosomal aberrations, and micronuclei 

in human lymphocytes and chromosomal aberrations 

and sister chromatid exchanges in cultured Chinese 

hamster ovary cells (Cid and Larripa, 1994). In these 

experiments, human lymphocytes appeared to be 

somewhat more sensitive to the genotoxic effects of 

AZT than were cultured Chinese hamster ovary cells 

(effective dose concentrations were lower in 

experiments with human lymphocytes). 

In vivo, AZT has been shown to be an effective inducer of micronucleated erythrocytes in mice and rats 

administered AZT in various combinations of routes 

and exposure durations (Oleson and Getman, 1990; 

Phillips et al., 1991). Increases in micronucleus 

frequencies of 6 to 27 times the concurrent control 

frequency were noted in peripheral blood and bone 

marrow erythrocytes of mice after multiple treatments 

with 100 to 2,000 mg/kg AZT per day for periods 

of 72 hours, 96 hours, or 90 days; no increase in 

the frequency of micronucleated erythrocytes was 

noted in mice after 90 days of treatment with a lower 

dose of 25 mg/kg AZT (Phillips et al., 1991). In 

apparent contrast to these positive results, negative 

results were reported in an in vivo bone marrow 

micronucleus test with male mice (Motimaya et al., 

1994); in this test, AZT was administered as a single 

intraperitoneal injection at doses ranging from about 

14 to 29 mg/kg and bone marrow was harvested 36 or 

48 hours after treatment (optimum harvest time is 

generally accepted to be 24 hours after treatment). 

The doses used in this experiment approximated the 

average daily total dose prescribed for humans, but 

used only a single treatment compared to the longterm chronic administrations employed in humans. 

The data reported by Motimaya et al. (1994), taken 

together with the Phillips et al. (1991) data, indicate 

that low doses of AZT may not induce damage 

detected as micronucleated erythrocytes in mice, but 

that multiple treatments with higher doses are 

extremely effective in inducing this type of genetic 

damage. 
AZT and AZT/"-Interferon A/D, NTP TR 469 23 

The relevance of these data to human genetic hazard 

is supported by the results of investigations performed 

by Shafik et al. (1991), who reported significantly 

increased frequencies of chromosomal aberrations 

(>8%) in lymphocytes of AIDS patients receiving 

AZT therapy compared to AIDS patients not receiving 

AZT. The frequency of chromosomal aberrations 

(0.5%) in the group not receiving AZT was comparable to the baseline frequency determined in a healthy 

adult population (Bender et al., 1988). The AZTtreated group had received the standard dosage of 

1,200 mg AZT per day for at least 4 weeks prior to 

this investigation. These data strongly suggest that at 

therapeutic doses, AZT can induce chromosomal 

damage in humans. 

STUDY RATIONALE 

The National Cancer Institute nominated AZT for 

toxicity and carcinogenicity studies in 1986 because of 

the impending large-scale use of AZT in the treatment 

of adult patients with AIDS or AIDS-related complex. 

A number of in vitro studies in human cells (reviewed 

in Poli et al., 1994) have shown that "- and 

$-interferon interfere with the replication of HIV 

at numerous steps during the viral life cycle. 

"-Interferon has also shown antineoplastic activity 

against AIDS-related Kaposi’s sarcoma (Lane, 1989; 

Lane et al., 1990). Moreover, in vitro studies of 

"-interferon and AZT have demonstrated that the 

combination is more effective in blocking HIV 

infection than either agent alone (Dubreuil et al., 

1990). Based on these findings, several clinical trials 

involving AZT and "-interferon combination therapy 

have been conducted. The present study was initiated 

to examine the potential risks associated with longterm exposure to AZT and how this might be 

influenced by coadministration of "-interferon. This 

study was conducted in male and female mice because 

of the more extensive database on the effects of AZT 

and interferons in mice and because the use of mice 

would minimize the quantity of AZT needed. Two 

separate recombinant interferons were selected: the 

hybrid discussed previously (rHIFN A/D), which is " 

active in mice, and rHIFN 2A, a pure recombinant " 

human interferon " subtype that exhibits no antiviral 

activity in mice. 
24 AZT and AZT/"-Interferon A/D, NTP TR 469 
25 

MATERIALS AND METHODS
 

PROCUREMENT 

AND CHARACTERIZATION 

AZT 

3N-Azido-3N-deoxythymidine (AZT) was obtained 

from the Burroughs Wellcome Company (Research 

Triangle Park, NC) in three lots (809796, 

80/0557-130-B, and 86/5082-184). Lot 809796 was 

used during the 14-week study and 2-year AZT 

and AZT/"-interferon A/D studies, and lots 

80/0557-130-B and 86/5082-184 were used during 

the 2-year AZT and AZT/"-interferon A/D studies. 

Identity, purity, and stability analyses were conducted 

by the analytical chemistry laboratory, Midwest 

Research Institute (Kansas City, MO) (Appendix O). 

Reports on analyses performed in support of the AZT 

and AZT/"-interferon A/D studies are on file at the 

National Institute of Environmental Health Sciences 

(NIEHS). 

All lots of the chemical, a white to slightly off-white 

fine powder, were identified as AZT by infrared spectroscopy. Lots 809796 and 80/0557-130-B were also 

identified by ultraviolet/visible and nuclear magnetic 

resonance spectroscopy and by melting point range. 

For lot 809796, the optical rotation value was consistent with values determined by the study laboratory, 

and an additional determination of the optical rotation 

value for lot 809796 indicated a value consistent with 

that reported by the supplier. For lot 80/0557-130-B, 

the optical rotation value was consistent with the 

results from the second determination for lot 809796. 

For lot 80/0557-130-B, the partition coefficient 

between octanol and pH 7.4 phosphate buffer was 

determined to be 0.05 at room temperature, and the 

maximum solubility in water at 25E C was determined 

to be 22.8 mg/mL. The purities of lots 809796 and 

80/0557-130-B were determined using elemental 

analyses, Karl Fischer water analysis, functional 

group titration, thin-layer chromatography, and highperformance liquid chromatography. For lot 809796, 

elemental analyses for carbon, hydrogen, and nitrogen 

were in agreement with the theoretical values for 

AZT. Karl Fischer water analysis indicated 

0.10% ± 0.03% water. Functional group titration 

indicated a purity of 101.4% ± 0.5%. Thin-layer 

chromatography by one system indicated a major spot 

and a trace impurity; thin-layer chromatography by 

another system indicated a major spot and a minor 

impurity. High-performance liquid chromatography 

indicated one major peak and two impurities with a 

combined area of 1.8% relative to the major peak 

area. One of these impurities was identified as thymine from an ultraviolet spectrum, and the thymine 

content was estimated to be 0.80% ± 0.01% with 

high-performance liquid chromatography. The overall 

purity of lot 809796 was determined to be approximately 98%. 

For lot 80/0557-130-B, elemental analyses for carbon, 

hydrogen, and nitrogen were in agreement with the 

theoretical values for AZT. Karl Fischer water 

analysis indicated 0.04% ± 0.01% water. Functional 

group titration indicated a purity of 102.1% ± 0.5%. 

Thin-layer chromatography by two systems indicated 

a major spot and a trace impurity. High-performance 

liquid chromatography indicated one major peak and 

two impurities with a combined area of 1.6% relative 

to the major peak area. Major peak comparisons of 

lot 80/0557-130-B with lot 809796 indicated a purity 

of 100.3% ± 0.9% for lot 80/0557-130-B relative to 

lot 809796. The overall purity of lot 80/0557-130-B 

was determined to be approximately 98%. 

The purity of lot 86/5082-184 relative to that of 

lot 80/0557-130-B was determined by the study 

laboratory with high-performance liquid chromatography. The purity of lot 86/5082-184 relative to 

lot 80/0557-130-B was determined to be approximately 102%. 

Accelerated stability studies of lot 809796 of the bulk 

chemical were performed by the analytical chemistry 

laboratory using high-performance liquid chromatography. These studies indicated that AZT was 

stable as a bulk chemical for at least 2 weeks when 

stored protected from light at temperatures up to 

60E C. To ensure stability, the bulk chemical was 

stored in the original container (double plastic bags 

inside a metal can) in the dark at room temperature 
26 AZT and AZT/"-Interferon A/D, NTP TR 469 

(approximately 22E C) for 2 months after receipt 

before the 14-week study began and at approximately 

!20E C thereafter. Stability was monitored during the 

14-week and 2-year studies using high-performance 

liquid chromatography. No degradation of the bulk 

chemical was detected. 

Methylcellulose 

Methylcellulose was obtained from Fisher Scientific 

Company (Pittsburgh, PA) in one lot (876672), which 

was used during the 14-week study, the 2-year AZT 

study, and the 2-year AZT/"-interferon A/D studies. 

Identity, purity, and stability analyses were conducted 

by the analytical chemistry laboratory. 

The chemical, a white powder, was identified as 

methylcellulose by infrared, ultraviolet/visible, and 

nuclear magnetic resonance spectroscopy. No melting 

point was observed up to 300E C; the sample 

decomposed at 250E to 300E C. The purity of 

lot 876672 was determined by elemental analyses, 

Karl Fischer water analysis, functional group titration, 

and high-performance liquid chromatography. The 

methoxy group content was estimated from the 

nuclear magnetic resonance spectrum. United States 

Pharmacopeia (USP) XXI analyses for the identification, apparent viscosity, weight loss on drying, 

residue on ignition, arsenic content, heavy metal 

content, and percent methoxy content were also 

performed. Elemental analyses for carbon and 

hydrogen were in agreement with the theoretical 

values for methylcellulose based on 1.8 degrees of 

substitution and corrected for 1.94% water (indicated 

by Karl Fischer water analysis). In addition, elemental analyses indicated 0.058% sodium. Functional 

group titration indicated 30.62% ± 0.08% methoxy 

group content; this value is consistent with the theoretical value, assuming 1.8 degrees of substitution 

(30.4%), and with the estimate of the methoxy group 

content from the nuclear magnetic spectrum (31.7%). 

The complete battery of USP tests for methylcellulose 

indicated the following results: the chemical was 

identified as methylcellulose; the apparent viscosity 

was 3,749 to 4,060 cP; the weight loss on drying was 

1.9% ± 0.3%; the residue on ignition was less than 

0.3%; the tests for arsenic and heavy metals were 

passed; and the methoxy group content was 

30.3% ± 0.2% for lot 876672 and 28.3% ± 0.0% 

for the USP reference material. The chemical met the 

USP specifications for methylcellulose for all 

analyses. High-performance liquid chromatography 

indicated one major peak and no impurities with areas 

greater than or equal to 0.1% relative to the major 

peak area. Cumulative analytical data indicated that 

lot 876672 of methylcellulose was suitable for use as 

a dosing vehicle. 

Accelerated stability studies of the bulk chemical were 

performed by the analytical chemistry laboratory 

using gas chromatography (USP XXI method). These 

studies indicated that methylcellulose was stable as a 

bulk chemical for 3 weeks when stored protected from 

light at temperatures up to 60E C. To ensure stability, 

the bulk chemical was stored in the original containers 

in the dark at room temperature. Stability was monitored by Galbraith Laboratories, Inc. (Knoxville, TN), 

during the 14-week and 2-year studies using gas 

chromatography to determine methoxy group content. 

Results of duplicate analyses were all within the 

required range of 27.5% to 31.5% methoxy group 

content. No degradation of the bulk chemical was 

detected. 

"-Interferon A/D and "-Interferon A 

"-Interferon A/D and "-interferon A were obtained 

from Hoffman-La Roche (Nutley, NJ). "-Interferon 

A/D was obtained in one lot (1084), which was 

used during the 2-year "-interferon A/D and AZT/ 

"-interferon A/D studies. "-Interferon A was obtained in one lot (019116), which was used during the 

2-year "-interferon A/D study. Antiviral activity 

assays were conducted by the study laboratory. 

Information from the manufacturer indicated a protein 

concentration of 2.8 mg/mL and a bulk activity of 8 1.5 × 10 U/mL for lot 1084 of "-interferon A/D and 

a protein concentration of 5.47 mg/mL and a bulk 

activity of 1.095 × 109 U/mL for lot 019116 of 

"-interferon A. The bulk chemical was stored in the 

original containers (plastic bottles) at approximately 

!20E C from receipt until 2 weeks before the 2-year 

studies began and at !140E or !180E C in the vapor 

phase of a liquid nitrogen cryopreservation vat 

thereafter. Each lot of the "-interferon A/D and 

"-interferon A bulk chemicals was evaluated by 

determining the ability to confer protection against 

viral challenge using the viral cytopathic effect assay 

(Table O1). Prior to the beginning of the studies, the 

antiviral activities (titers) of "-interferon A/D and 

"-interferon A were determined along with that of an 

international standard " 2-interferon obtained from the 

National Institute of Allergy and Infectious Diseases. 
AZT and AZT/"-Interferon A/D, NTP TR 469 27 

Complete details of the procedures used and the 

results are on file at NIEHS. 

PREPARATION AND ANALYSIS 

OF DOSE FORMULATIONS 

AZT 

The dosing vehicle was prepared by mixing methylcellulose with heated deionized water and then 

diluting with water to form a 0.5% solution, which 

was allowed to cool. AZT was then mixed with the 

dosing vehicle until a homogeneous suspension 

was obtained to give the required concentrations (Table O2). The dose formulations were stored 

at room temperature (at the beginning of the 14-week 

study) or refrigerated at approximately 5E C in amber 

glass bottles in the dark for up to 20 days. Homogeneity studies of a 200 mg/g solution of lot 809796 

were performed by the analytical chemistry laboratory using high- performance liquid chromatography. Stability studies of a 2 mg/g solution were 

also performed using high-performance liquid 

chromatography. Homogeneity was confirmed, and 

the stability of the solution was confirmed for 3 weeks 

at room temperature when stored in the dark and for 

3 hours when open to air and light. 

The periodic analyses of the dose formulations 

of AZT were conducted at the study laboratory using 

high-performance liquid chromatography. During all 

studies, the formulations were analyzed every 4 to 

8 weeks (Tables O3 and O4). All of the dose formulations analyzed and used during the 14-week and 

2-year studies were within 10% of the target concentrations. All of the animal room samples were also 

within 10% of the target concentrations. 

"-Interferon A/D and "-Interferon A 

The dosing vehicle was prepared by aseptically mixing sterile C57Bl/6 mouse serum (Harlan SpragueDawley, Inc., Indianapolis, IN) in Earle’s Balanced 

Salt Solution (Grand Island Biologicals Co.) to 

achieve a 10% solution, which was adjusted to a pH 

of approximately 7.2. Based on titers determined for 

the bulk chemicals, dose formulations were prepared 

by dilution of the stock solution. Therefore, the same 

amount (quantity of pure recombinant protein) of 

"-interferon A/D or "-interferon A was administered 

to the animals throughout the 2-year studies. 

"-Interferon A/D and "-interferon A were thawed at 

room temperature, and serial dilutions were prepared 

in the vehicle under sterile conditions using sterile 

pipettes and a calibrated Matrix Electropette 

(Table O2). The dose formulations were stored in 

sterile, Teflon®-capped, brown glass dosing vials at 

4E C. Samples for antiviral activity assays were 

stored at !140E C or cryopreserved in liquid nitrogen. 

Sterility of the dose preparations was monitored 

with a 2-week incubation in both Sabouraud’s broth 

and thioglycollate broth at 37E C followed by a visual 

examination for microbial growth. Stability of 

"-interferon A/D and "-interferon A dose 

formulations had been previously established for 

42 days. 

Periodic analyses of the antiviral activity of the dose 

formulations of "-interferon A/D and "-interferon A 

were conducted at the study laboratory using the same 

methods as for the bulk chemicals. Those assays 

demonstrated that interferon dose formulations used in 

the studies retained antiviral activity under normal 

dosing conditions. However, the differences between 

the titers of dose formulations determined by the 

cytopathic effect assay (observed) and the titers 

expected from making known dilutions of the calibrated laboratory standards (theoretical) were consistently greater than 10%. Because of this variability 

and the demonstrated stability of antiviral activity 

under dosing conditions, routine analysis of interferon 

dose formulations by the cytopathic effect assay was 

discontinued in October 1991. The long-term stability 

of laboratory standards from which dose formulations 

were prepared was confirmed with the cytopathic 

effect assay in March 1993. 

14-WEEK STUDY 

The 14-week study was conducted to evaluate the 

cumulative toxic effects of repeated exposure to AZT 

and to determine the appropriate doses to be used in 

the 2-year studies. A recovery group was included to 

evaluate the reversibility of toxicity in male and 

female mice allowed a 4-week recovery period after 

the 14-week dosing period ended. 

Male and female B6C3F1 mice were obtained from 

Simonsen Laboratories, Inc. (Gilroy, CA). At the 

time of receipt, the mice were 4 weeks old. Animals 

were quarantined for 11 days and were approximately 

6 weeks old on the first day of the study. Before the 
28 AZT and AZT/"-Interferon A/D, NTP TR 469 

study began, five male and five female mice were 

randomly selected for parasite evaluation and gross 

observation for evidence of disease. At the end of the 

study, serologic analyses were performed on five male 

and three female 50 mg/kg mice using the protocols of 

the NTP Sentinel Animal Program (Appendix Q). 

Groups of 10 male and 10 female mice received AZT 

in 0.5% methylcellulose by gavage at doses of 0, 50, 

100, 200, 800, or 2,000 mg/kg, daily for 14 weeks. 

Additional groups of 10 male and 10 female mice 

received AZT in 0.5% methylcellulose by gavage at 

doses of 0, 100, 800, or 2,000 mg/kg, daily for 

14 weeks, and then were held without treatment for an 

additional 4 weeks before necropsy. All doses were 

administered twice daily (one half the total daily dose) 

except on days of neurobehavioral evaluations. Feed 

and water were available ad libitum. Mice were 

housed individually. Clinical findings were recorded 

weekly for mice. The animals were weighed initially 

and then weekly throughout the study. Details of the 

study design and animal maintenance are summarized 

in Table 4. 

On days 5 and 23 and at the end of the 14-week 

dosing period for core study mice and on day 89 and 

at the end of the holding period for recovery group 

mice, blood was collected from the retroorbital sinus 

of all animals for hematology analyses. Bone marrow 

analyses were performed on 0, 100, 800, and 

2,000 mg/kg core study mice at the end of the dosing 

period and on recovery group mice at the end of the 

holding period. Blood for hematology determinations 

was placed in tubes containing EDTA as an anticoagulant. Erythrocyte, platelet, and leukocyte 

counts, hematocrit values, hemoglobin concentration, 

mean cell volume, mean cell hemoglobin, and mean 

cell hemoglobin concentration were determined 

using an Ortho ELT-8 (Ortho Instruments, Westwood, 

MA) or a Technicon H@1 (Technicon Corporation, 

Tarrytown, NY) hematology analyzer. Differential 

leukocyte counts, reticulocyte and nucleated erythrocyte counts, and morphologic evaluation of blood 

cells were determined by light microscopic evaluation 

of blood films. Bone marrow suspensions were 

produced by flushing the femurs with Modified Hanks 

Balanced Salt Solution (HBSS) containing EDTA and 

albumin supplements. Total nucleated cell counts 

were determined using a Technicon H@1. The 

suspensions were further diluted with HBSS and 

centrifuged. Cells were stained with Wright-Giemsa 

and evaluated with oil-immersion light microscopy. 

At least 500 cells per slide were differentially 

identified and counted. The hematology and bone 

marrow parameters measured are listed in Table 4. 

Neurobehavioral evaluations were conducted prior to 

the beginning of the study and on days 44 and 88 for 

core study mice and on day 116 (females) or 

117 (males) for recovery group mice. Mice in the 0, 

100, 800, and 2,000 mg/kg groups were subjected to 

the following behavioral tests: 1) a functional 

observational battery which included the assessment of 

home cage behaviors, handling behaviors, 

physiological measures, open field behavior, reflex 

responses, and the measurement of forelimb and 

hindlimb grip strength; 2) motor activity; 3) thermal 

sensitivity; and 4) startle response. 

The sequence of neurobehavioral evaluations was such 

that the least interactive test was conducted first with 

the most manipulative procedures being performed 

last. For functional observations, animals were first 

rated on posture, presence or absence of tonic or 

clonic convulsions, vocalizations, and palpebral closure. Animals were then removed from the cage and 

various handling measures were recorded, including 

general observation, ease of removal from the cage, 

ease of handling, lacrimation, palpebral closure, fur 

appearance, piloerection, and salivation. Then the 

animals were weighed and their body temperatures 

were recorded. Animals were placed individually in 

an open field for 3 minutes. During this time animals 

were observed for the number of rears (supported and 

unsupported), presence or absence of tonic or clonic 

convulsions, gait and gait score, mobility score, 

arousal level, presence or absence of stereotyped 

behavior, and number of fecal boli or urine pools. 

Observations were recorded for the following responses or reflexes: approach, touch, click, tail pinch 

(including the presence or absence of vocalizations to 

tail pinch), pupil, righting, and landing footsplay. 

Forelimb and hindlimb grip strengths were measured 

using strain gauges (Chatillion Force Measurement 

Co., Greensboro, NC). 

Measurement of motor activity was performed using 

Opto-Varimax Mini activity monitors (Columbus 

Instruments International Corporation, Columbus, 

OH). Animal motor activity was monitored for 

10 minutes, after which time a score was recorded for 

ambulatory behavior and for other behaviors (e.g., 
 

AZT and AZT/"-Interferon A/D, NTP TR 469 29 

grooming). The time it took each animal to remove 

its tail from a 55E C water bath (tail-flick response) 

was recorded to determine thermal sensitivity. 

Animals were exposed to an acoustic stimulus and an 

air puff stimulus to determine startle response in terms 

of reactivity and excitability. The latency to respond, 

peak threshold, and time of the peak were recorded 

using a Responder-X Startle Monitor (Columbus 

Instruments International Corporation, Columbus, 

OH). 

At the end of the 14-week dosing period, samples 

were collected for sperm motility evaluations from 

core study and recovery group male mice receiving 0, 

100, 800, or 2,000 mg/kg. For recovery group 

females, vaginal samples were collected at the end of 

the 14-week dosing period and again at the end of the 

4-week recovery period for vaginal cytology evaluations. The parameters evaluated are listed in 

Table 4. Methods used were those described in the 

NTP’s sperm morphology and vaginal cytology evaluations protocol (NTP, 1987). For 12 consecutive 

days prior to the end of dosing and again prior to the 

end of the recovery period, the vaginal vaults of the 

females were moistened with saline, if necessary, and 

samples of vaginal fluid and cells were stained. 

Relative numbers of leukocytes, nucleated epithelial 

cells, and large squamous epithelial cells were determined and used to ascertain estrous cycle stage (i.e., 

diestrus, proestrus, estrus, and metestrus). Male 

animals were evaluated for sperm count and motility. 

The left testis and left epididymis were isolated and 

weighed. The tail of the epididymis (cauda epididymis) was then removed from the epididymal body 

(corpus epididymis) and weighed. Modified Tyrode’s 

buffer was applied to slides and a small incision was 

made at the distal border of the cauda epididymis. 

The sperm effluxing from the incision were dispersed 

in the buffer on the slides, and the numbers of motile 

and nonmotile spermatozoa were counted for 

five fields per slide by two observers. Following 

completion of sperm motility estimates, each left 

cauda epididymis was placed in buffered saline 

solution. Caudae were finely minced, and the tissue 

was incubated in the saline solution and then heat 

fixed at 65E C. Sperm density was then determined 

microscopically with the aid of a hemacytometer. To 

quantify spermatogenesis, the testicular spermatid 

head count was determined by removing the tunica 

albuginea and homogenizing the left testis in 

phosphate-buffered saline containing 10% dimethyl 

sulfoxide. Homogenization-resistant spermatid nuclei 

were counted with a hemacytometer. 

A necropsy was performed on all animals. The heart, 

left and right kidneys, liver, lung, right testis, and 

thymus were weighed. Tissues for microscopic 

examination were fixed and preserved in 10% neutral 

buffered formalin, processed and trimmed, embedded 

in paraffin, sectioned to a thickness of 5 to 6 μm, and 

stained with hematoxylin and eosin. Sections of 

brain, spinal cord, and sciatic nerve from all mice 

were also stained with Luxol fast blue and Holmes 

silver. A complete histopathologic examination was 

performed on all mice. Table 4 lists the tissues and 

organs routinely examined. 

2-YEAR STUDIES 

Study Design 

Because of the large number of animals involved, the 

2-year studies were started in four phases: the AZT 

study, the "-interferon A/D study, the AZT/500 U 

"-interferon A/D study, and the AZT/5,000 U 

"-interferon A/D study. Table 3 shows a matrix of 

the overall study design. 

For the AZT study, groups of 95 male and 95 female 

mice received AZT in 0.5% aqueous methylcellulose 

by gavage at daily doses of 0, 30, 60, or 120 mg/kg 

body weight, administered as two equal doses (one in 

the morning and one in the afternoon, at least 6 hours 

apart), 5 days per week for 105 weeks. Each group 

of 95 mice was composed of the following: 1) a core 

group of 50 mice for evaluation of carcinogenic 

response, 2) a group of 30 mice for clinical pathology 

analyses, and 3) a group of 15 mice from which blood 

was collected at week 54 after the first daily dose was 

administered for determinations of plasma AZT 

concentrations. At the end of the study, up to 

10 mice from each study core group were evaluated 

for alterations in hematology and bone marrow parameters, and up to 23 mice were evaluated for plasma 

AZT concentrations. The clinical pathology groups 

were further divided into three groups of 10 mice 

each. Blood for hematology determinations was 

collected from each group of 10 mice at two time 

points, 6 months apart. After the second collection, 

mice in that group were euthanized with CO , and

bone marrow samples were collected for determination of marrow cellularity. Therefore, hematology 

2 
30 AZT and AZT/"-Interferon A/D, NTP TR 469 

parameters were evaluated at six time points during 

the study (weeks 14, 27, 40, 54, 66, and 80), and 

bone marrow was evaluated at three time points 

during the study (weeks 54, 66, and 80). 

For the "-interferon A/D study, groups of 80 male 

and 80 female mice received subcutaneous injections 

of 0, 500 or 5,000 U "-interferon A/D, or 5,000 U 

"-interferon A, three times per week, for 105 weeks. 

For the AZT/"-interferon A/D studies, groups of 

80 male and 80 female mice received AZT in 

0.5% aqueous methylcellulose by gavage at daily 

doses of 0, 30, 60, or 120 mg/kg body weight, 

administered as two equal doses (one in the morning 

and one in the afternoon, at least 6 hours apart), 

5 days per week for 105 weeks. The dosed groups 

also received subcutaneous injections of 500 or 

5,000 U "-interferon A/D three times per week. For 

the "-interferon A/D study and the AZT/"-interferon 

A/D studies, each group of 80 mice was composed of 

the following: 1) a core group of 50 mice for 

evaluation of carcinogenic response and 2) a group of 

30 mice for clinical pathology analyses. At the end of 

the study, up to 10 mice from each core group were 

evaluated for alterations in hematology and bone 

marrow parameters. The clinical pathology groups 

were further divided into three groups of 10 mice 

each. Blood for hematology determinations was 

collected from each group of 10 mice at two 

timepoints, approximately 9 months apart. After the 

second collection, mice were euthanized with CO ,2 

and bone marrow samples were collected for determination of marrow cellularity. Therefore, hematology parameters were evaluated at six time points 

during the study (weeks 14, 27, 40, 54, 65 or 66, and 

79), and bone marrow was evaluated at three time 

points during the study (weeks 54, 65 or 66, and 79). 

TABLE 3 

Design of the 2-Year AZT, AZT/"-Interferon A/D, and "-Interferon A/D Studies 

AZT Dose AZT Study "-Interferon A/D 

AZT/500 U 

Study 

"-Interferon A/D 

AZT/5,000 U 

Study 

5,000 U "-Interferon A 

"-Interferon A/D or 

Study 

500 or 5,000 U 

Vehicle Control 95 male and 

95 female micea 80 male and 80 female miceb 

80 male and 

80 female miceb 

80 male and 

80 female miceb 

30 mg/kg AZT 95 male and 

95 female mice 

80 male and 

80 female mice 

80 male and 

80 female mice 

None 

60 mg/kg AZT 95 male and 

95 female mice 

80 male and 

80 female mice 

80 male and 

80 female mice 

None 

120 mg/kg AZT 95 male and 

95 female mice 

80 male and 

80 female mice 

80 male and 

80 female mice 

None 

a For the AZT study, there were 95 male and 95 female mice; these were divided into 50 males and 50 females in the core groups, 30 males 

and 30 females in the clinical pathology groups (hematology and bone marrow analyses only), and 15 males and 15 females for plasma AZT 

concentration determinations. 

b	 For the "-interferon A/D study and the AZT/"-interferon A/D studies, there were 80 male and 80 female mice for each study; these were 

divided into 50 males and 50 females in the core groups and 30 males and 30 females in the clinical pathology groups (hematology and bone 

marrow analyses only). 

Source and Specification of Animals 

Male and female B6C3F1 mice were obtained from 

Simonsen Laboratories, Inc. (Gilroy, CA) for use in 

the 2-year studies. Mice were quarantined for 17 to 

20 days before the beginning of the studies. Up to 

five male and five female mice per study design group 

were randomly selected for parasite evaluation and 

gross observation of disease. Mice were 

approximately 7 to 8 weeks old at the beginning of the 

studies. Throughout the studies, serology samples 
AZT and AZT/"-Interferon A/D, NTP TR 469 31 

were collected periodically from up to five male and 

five female sentinel mice from the core study and 

clinical pathology groups, and occasionally from mice 

in the dosed groups in each study. The health of the 

animals was monitored during the studies according to 

the protocols of the NTP Sentinel Animal Program 

(Appendix Q). Because mouse hepatitis virus was 

detected in dosed and sentinel mice, additional (naive) 

sentinels were obtained and monitored during the 

AZT study; no antibody titers to mouse hepatitis virus 

were detected in sera from the naive sentinels. 

Animal Maintenance 

Mice were housed five per cage during the quarantine 

period and individually during the studies. Feed and 

water were available ad libitum. Cages and racks 

were rotated every 2 weeks, cage filters were changed 

once every 2 weeks, and bedding was changed once 

per week. Further details of animal maintenance are 

given in Table 4. Information on feed composition 

and contaminants is provided in Appendix P. 

Clinical Examinations and Pathology 

All animals were observed twice daily. Clinical findings were recorded at the beginning of the studies and 

monthly thereafter. Body weights were recorded at 

the beginning of the studies, approximately weekly for 

the first 13 weeks, monthly thereafter, and at the end 

of the studies. 

Blood was collected from the retroorbital sinus for 

hematology analyses. Methodologies were similar to 

those described for the 14-week study. A Technicon 

H@1 hematology analyzer was used for hematology 

determinations. Whole blood films were stained with 

new methylene blue for reticulocyte counts. Bone 

marrow suspensions were produced by flushing the 

femurs with HBSS containing EDTA, gentamicin, and 

albumin supplements. The parameters measured are 

listed in Table 4. 

At week 54 of the 2-year AZT study, blood was 

collected from the retroorbital sinus of as many as 

15 male and 15 female mice per group designated for 

the determination of plasma concentrations of AZT. 

Three animals per group were examined at each of 

five time points (15, 30, 60, 90, or 120 minutes after 

dosing). On the last day of the 2-year AZT study, 

blood was collected from the retroorbital sinus of 

18 male and 18 female mice from each core study 

dosed group at six time points (5, 15, 30, 60, 90, or 

120 minutes after dosing), with three animals per 

group evaluated at each time point. Mice designated 

for the determination of plasma concentrations of 

AZT were fasted overnight prior to dosing and 

received only one of the two equal doses of AZT on 

the day blood was collected. Blood was also collected 

from five males and five females from the 30, 60, and 

120 mg/kg core groups before any doses were 

administered on the last day of the study. Blood was 

placed in tubes containing EDTA as the anticoagulant, 

the tubes were centrifuged, and the plasma was 

removed. The plasma was stored at approximately 

!20E C until analysis. Plasma samples were analyzed 

using high-performance liquid chromatography for the 

analysis of concentrations of AZT. The mean plasma 

concentrations of AZT and standard deviations were 

calculated. 

A complete necropsy was performed on all mice and 

microscopic examination was performed on all core 

study mice. At necropsy, all organs and tissues were 

examined for grossly visible lesions, and all major 

tissues were fixed and preserved in 10% neutral 

buffered formalin, processed and trimmed, embedded 

in paraffin, sectioned to a thickness of 5 to 6 μm, and 

stained with hematoxylin and eosin for microscopic 

examination. For all paired organs (e.g., adrenal 

gland, kidney, ovary), samples from each organ were 

examined. Tissues examined microscopically are 

listed in Table 4. 

Microscopic evaluations were completed by the study 

laboratory pathologist, and the pathology data were 

entered into the Toxicology Data Management 

System. The microscopic slides, paraffin blocks, and 

residual wet tissues were sent to the NTP Archives for 

inventory, slide/block match, and wet tissue audit. 

The slides, individual animal data records, and pathology tables were evaluated by an independent 

quality assessment laboratory. The individual animal 

records and tables were compared for accuracy, the 

slide and tissue counts were verified, and the histotechnique was evaluated. For the 2-year AZT study, 

a quality assessment pathologist evaluated slides from 

all tumors and all potential target organs, which 

included the adrenal gland, bone marrow, harderian 

gland, kidney, and liver of male mice and the bone 

marrow, kidney, liver, and vagina of female mice. 

For the 2-year "-interferon A/D study, a quality 

assessment pathologist evaluated slides from all 

tumors and all potential target organs, which included 

the kidney and liver of male mice and the kidney, 
32 AZT and AZT/"-Interferon A/D, NTP TR 469 

liver, spleen, thyroid gland, uterus, and vagina of assessment pathologists. Representative histofemale mice. For the 2-year AZT/500 U "-inter- pathology slides containing examples of lesions 

feron A/D study, a quality assessment pathologist related to chemical administration, examples of 

evaluated slides from all tumors and all potential disagreements in diagnoses between the laboratory 

target organs, which included the adrenal gland, and quality assessment pathologists, or lesions of 

kidney, and liver of male mice and the adrenal gland, general interest were presented by the chairperson 

bone marrow, kidney, liver, spleen, uterus, and to the PWG for review. The PWG consisted of the 

vagina of female mice. For the 2-year AZT/5,000 U quality assessment pathologist and other pathologists 

"-interferon A/D study, a quality assessment experienced in rodent toxicologic pathology. This 

pathologist evaluated slides from all tumors and all group examined the tissues without any knowledge of 

potential target organs, which included the adrenal dose groups or previously rendered diagnoses. When 

gland, bone marrow, harderian gland, kidney, liver, the PWG consensus differed from the opinion of the 

lymph node, preputial gland, stomach (glandular), laboratory pathologist, the diagnosis was changed. 

thyroid gland, and tooth of male mice and the adrenal Final diagnoses for reviewed lesions represent a 

gland, bone marrow, kidney, liver, pituitary gland, consensus between the laboratory pathologist, 

spleen, stomach (forestomach and glandular), thyroid reviewing pathologist(s), and the PWG. Details of 

gland, and vagina of female mice. these review procedures have been described, in part, 

by Maronpot and Boorman (1982) and Boorman et al. 

The quality assessment report and the reviewed slides (1985). For subsequent analyses of the pathology 

were submitted to the NTP Pathology Working Group data, the decision of whether to evaluate the diagnosed 

(PWG) chairperson, who reviewed the selected lesions for each tissue type separately or combined 

tissues and addressed any inconsistencies in the was generally based on the guidelines of McConnell 

diagnoses made by the laboratory and quality et al. (1986). 
AZT and AZT/"-Interferon A/D, NTP TR 469 33 

TABLE 4 

Experimental Design and Materials and Methods in the Gavage Studies of AZT and AZT/"-Interferon A/D 

14-Week Study	 2-Year Studies 

Study Laboratory 

Southern Research Institute (Birmingham, AL)	 Southern Research Institute (Birmingham, AL) 

Strain and Species 

B6C3F mice B6C3F mice 1 1 

Animal Source 

Simonsen Laboratories, Inc. (Gilroy, CA)	 Simonsen Laboratories, Inc. (Gilroy, CA) 

Time Held Before Studies 

11 days	 17–20 days 

Average Age When Studies Began 

6 weeks	 7–8 weeks 

Date of First Dose 

10 April 1989 (males) or 3 April 1989 (females)	 AZT: 9 July 1990 

"-Interferon A/D: 5 September 1990 

AZT/500 U "-Interferon A/D: 8 October 1990 

AZT/5,000 U "-Interferon A/D: 14 January 1991 

All studies: Dosing of groups designated for clinical pathology 

analyses and determination of plasma AZT concentrations began 

5–7 days after core study dosing began. 

Duration of Dosing 

93 days (core study); 92 days (recovery group)	 105 weeks 

Date of Last Dose 

11 July 1989 (males) or 4 July 1989 (females) (core study); AZT: 8 July 1992 (males) or 10 July 1992 (females) 

10 July 1989 (males) or 3 July 1989 (females) (recovery group) "-Interferon A/D: 2 September 1992 

AZT/500 U "-Interferon A/D: 8 October 1992 (males) or 

6 October 1992 (females) 

AZT/5,000 U "-Interferon A/D: 12 January 1993 (males) or 

14 January 1993 (females) 

Necropsy Dates 

12 July 1989 (males) or 5 July 1989 (females) (core study); AZT: 6–8 July 1992 (males) or 8–10 July 1992 (females) 

8 August 1989 (males) or 1 August 1989 (females) (recovery "-Interferon A/D: 1–3 September 1992 (males) or 

group) 2–4 September 1992 (females) 

AZT/500 U "-Interferon A/D: 7–9 October 1992 (males) or 

5–7 October 1992 (females) 

AZT/5,000 U "-Interferon A/D: 11–13 January 1993 (males) or 

12–15 January 1993 (females) 

Average Age at Necropsy 

20 weeks (core study); 23 weeks (recovery group)	 112 weeks 

Size of Study Groups 

10 males and 10 females	 50 males and 50 females (core groups) 

30 males and 30 females (clinical pathology groups) 

15 males and 15 females (plasma AZT determination groups) 
34 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE 4 

Experimental Design and Materials and Methods in the Gavage Studies of AZT and AZT/"-Interferon A/D 

14-Week Study 2-Year Studies 

Method of Distribution 

Animals were distributed randomly into groups of approximately 

equal initial mean body weights. 

Animals per Cage 

1 

Method of Animal Identification 

Tail tattoo; mice were later identified by ear punch because the 

skin of the tails became dark and made it difficult to read the 

tattoos. 

Diet 

NIH-07 open formula pelleted diet (Zeigler Brothers, Inc., 

Gardners, PA), available ad libitum 

Water 

Tap water (Birmingham municipal supply) via automatic watering 

system (Edstrom Industries, Inc., Waterford, WI), available 

ad libitum 

Cages 

Solid-bottom polycarbonate (Lab Products, Inc., Maywood, NJ), 

rotated every 2 weeks 

Bedding 

Sani-Chips® heat-treated hardwood chips (P.J. Murphy Forest 

Products, Montville, NJ), changed once per week 

Cage Filters 

Reemay® spun-bonded polyester (Andico, Birmingham, AL), 

changed once every 2 weeks 

Racks 

Stainless steel (Lab Products, Inc., Maywood, NJ), rotated once 

every 2 weeks 

Animal Room Environment 

Temperature: 20.4E–24.1E C (males); 20.6E–24.5E C (females)
 

Relative humidity: 37%–83% (males); 38%–81% (females)
 

Fluorescent light: 12 hours/day
 

Room air changes: at least 10/hour
 

Same as 14-week study 

1 

Microchip implant 

Same as 14-week study 

Same as 14-week study 

Same as 14-week study 

Same as 14-week study 

Same as 14-week study 

Same as 14-week study 

AZT: 

Temperature: 17.9E–27.8E C 

Relative humidity: 27%–83% 

Fluorescent light: 12 hours/day 

Room air changes: at least 10/hour 

"-Interferon A/D: 

Temperature: 17.0E–25.9E C 

Relative humidity: 22%–87% 

Fluorescent light: 12 hours/day 

Room air changes: at least 10/hour 

AZT/500 U "-Interferon A/D: 

Temperature: 12.8E–24.4E C 

Relative humidity: 18%–89% 

Fluorescent light: 12 hours/day 

Room air changes: at least 10/hour 

AZT/5,000 U "-Interferon A/D: 

Temperature: 14.8E–24.3E C 

Relative humidity: 15%–89% 

Fluorescent light: 12 hours/day 

Room air changes: at least 10/hour 

TABLE 4 
AZT and AZT/"-Interferon A/D, NTP TR 469 35 

Experimental Design and Materials and Methods in the Gavage Studies of AZT and AZT/"-Interferon A/D 

14-Week Study 2-Year Studies 

Doses 

0, 50, 100, 200, 800, or 2,000 mg/kg body weight in 0.5% AZT: Daily doses of 0, 30, 60, or 120 mg AZT/kg body weight in 

methylcellulose by gavage at a volume of 20 mL/kg body weight, 0.5% methylcellulose by gavage at a volume of 10 mL/kg body 

given 7 days per week in two equal doses of 0, 25, 50, 100, 400, weight, given 5 days per week in two equal doses 

or 1,000 mg/kg per dose, except on days of neurobehavioral "-Interferon A/D: 0, 500, or 5,000 U "-interferon A/D, or 

testing (core study); 0, 100, 800, or 2,000 mg/kg body weight in 5,000 U "-interferon A at a volume of 0.5 mL/dose, administered 

0.5% methylcellulose by gavage at a volume of 20 mL/kg body subcutaneously three times per week 

weight, given 7 days per week in two equal doses of 0, 50, 400, AZT/500 U "-Interferon A/D: Daily doses of 0, 30, 60, or 120 mg 

or 1,000 mg/kg per dose, except on days of neurobehavioral AZT/kg body weight in 0.5% methylcellulose by gavage at a volume 

testing (recovery group) of 10 mL/kg body weight, given 5 days per week in two equal doses. 

Dosed groups also received 500 U "-interferon A/D at a volume of 

0.5 mL/dose, administered subcutaneously three times per week. 

AZT/5,000 U "-Interferon A/D: Daily doses of 0, 30, 60, or 120 mg 

AZT/kg body weight in 0.5% methylcellulose by gavage at a volume 

of 10 mL/kg body weight, given 5 days per week in two equal doses. 

Dosed groups also received 5,000 U "-interferon A/D at a volume of 

0.5 mL/dose, administered subcutaneously three times per week. 

Type and Frequency of Observation 

Observed twice daily; animals were weighed initially and then Observed twice daily; animals were weighed initially, weekly for 

weekly throughout the study; clinical findings were recorded approximately 13 weeks, monthly thereafter, and at the end of the 

weekly. Feed consumption was measured weekly. studies; clinical findings were recorded at the beginning of the studies 

and monthly thereafter. 

Method of Sacrifice 

CO2 asphyxiation CO2 asphyxiation

Necropsy 

Necropsy was performed on all animals. Organs weighed were Necropsy was performed on all animals. 

the heart, left and right kidneys, liver, lung, right testis, and 

thymus. 
36 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE 4 

Experimental Design and Materials and Methods in the Gavage Studies of AZT and AZT/"-Interferon A/D 

14-Week Study 2-Year Studies 

Clinical Pathology 

On days 5 and 23 and at the end of the 14-week dosing period 

(core study) and on day 89 and at the end of the holding period 

(recovery group), blood was collected from the retroorbital sinus 

of all animals for hematology analyses. Bone marrow analyses 

were performed on 0, 100, 800, and 2,000 mg/kg core study mice 

at the end of the dosing period and on recovery group mice at the 

end of the holding period. 

Hematology: hematocrit; hemoglobin concentration; erythrocyte, 

reticulocyte, and nucleated erythrocyte counts; mean cell volume; 

mean cell hemoglobin; mean cell hemoglobin concentration; 

platelet count; and leukocyte count and differentials 

Bone Marrow Analyses: total femoral count, M:E ratio, 

rubriblasts, prorubricytes, rubricytes, metarubricytes, myeloblasts, 

promyelocytes, myelocytes (basophilic, eosinophilic, and 

neutrophilic), metamyelocytes (basophilic, eosinophilic, and 

neutrophilic), bands (basophilic, eosinophilic, and neutrophilic), 

segments (basophilic, eosinophilic, and neutrophilic), 

lymphocytes, macrophages, monocytes, megakaryo cells, plasma 

cells, mitotic figures, fat cells, mast cells, smudge cells, 

osteoblasts, osteoclasts, and other bone marrow cells 

Histopathology 

Complete histopathology was performed on all animals. In 

addition to gross lesions and tissue masses, the following tissues 

were examined: adrenal gland, brain, clitoral gland, esophagus, 

femur and marrow, gallbladder, heart and aorta, large intestine 

(cecum, colon, rectum), small intestine (duodenum, jejunum, 

ileum), kidney, liver, lung, lymph nodes (mandibular, 

mesenteric), mammary gland, nose, ovary, pancreas, parathyroid 

gland, pituitary gland, preputial gland, prostate gland, salivary 

gland, seminal vesicle, skin, spinal cord, spleen, testes and 

epididymis, thigh muscle, thymus, thyroid gland, trachea, urinary 

bladder, uterus, and vagina (from animals used in vaginal cytology 

evaluations). 

Sperm Motility and Vaginal Cytology 

At the end of the 14-week dosing period, samples were collected 

for sperm motility evaluations from core study and recovery group 

male mice receiving 0, 100, 800, or 2,000 mg/kg. The following 

parameters were evaluated: sperm count and motility; epididymal 

spermatozoal data; and left cauda, left epididymis, and left testis 

weights. For recovery group females, vaginal samples were 

collected up to 12 consecutive days prior to the end of the 14-week 

dosing period and again before the end of the 4-week recovery 

period for vaginal cytology evaluations. The parameters evaluated 

were relative frequency of estrous stages and estrous cycle length. 

Blood was collected from the retroorbital sinus of up to 10 mice per 

clinical pathology group at 14, 27, and 40 weeks for hematology 

determinations. Blood was also collected from the retroorbital sinus of 

up to 10 mice per clinical pathology group at 54, 65 or 66, and 79 or 

80 weeks and from up to 10 core study mice per group at study 

termination for hematology determinations. Bone marrow analyses 

were performed on up to 10 mice per clinical pathology group at 54, 65 

or 66, and 79 or 80 weeks and up to 10 core study mice per group at 

study termination. 

Hematology: hematocrit; hemoglobin concentration; erythrocyte, 

reticulocyte, and nucleated erythrocyte counts; mean cell volume; mean 

cell hemoglobin; mean cell hemoglobin concentration; platelet count; 

and leukocyte count and differentials 

Bone Marrow Analyses: total femoral count, M:E ratio, rubriblasts, 

prorubricytes, rubricytes, metarubricytes, myeloblasts, promyelocytes, 

myelocytes (basophilic, eosinophilic, and neutrophilic), metamyelocytes 

(basophilic, eosinophilic, and neutrophilic), bands (basophilic, 

eosinophilic, and neutrophilic), neutrophilic hypersegments, segments 

(basophilic, eosinophilic, and neutrophilic), lymphocytes, macrophages, 

monocytes, megakaryo cells, plasma cells, mitotic figures, fat cells, 

mast cells, smudge cells, osteoblasts, osteoclasts, and other bone 

marrow cells 

Complete histopathology was performed on all core study animals. In 

addition to gross lesions and tissue masses, the following tissues were 

examined: adrenal gland, brain, clitoral gland, esophagus, femur and 

marrow, gallbladder, heart and aorta, kidney, large intestine (cecum, 

colon, rectum), small intestine (duodenum, jejunum, ileum), liver, 

lungs and bronchi, lymph nodes (mandibular, mesenteric), mammary 

gland, thigh muscle, nose, ovary, pancreas, parathyroid gland, pituitary 

gland, preputial gland, prostate gland, salivary gland, seminal vesicle, 

spleen, stomach (forestomach and glandular stomach), testes and 

epididymis, thymus, thyroid gland, trachea, urinary bladder, uterus, and 

vagina. 

None 
AZT and AZT/"-Interferon A/D, NTP TR 469 37 

TABLE 4 

Experimental Design and Materials and Methods in the Gavage Studies of AZT and AZT/"-Interferon A/D 

14-Week Study 2-Year Studies 

Neurobehavioral Studies 

Neurobehavioral evaluations were conducted prior to the None 

beginning of the study and on days 44 and 88 for core study mice 

and on day 117 (males) or 116 (females) for recovery group mice. 

All mice in the 0, 100, 800, and 2,000 mg/kg groups were 

subjected to the following behavioral tests: 1) a functional 

observational battery which included the assessment of home cage 

behaviors, handling behaviors, physiological measures, open field 

behavior, reflex responses, and the measurement of forelimb and 

hindlimb grip strength; 2) motor activity; 3) thermal sensitivity; 

and 4) startle response. 

Determinations of AZT in Plasma 

None At week 54 of the 2-year AZT study, blood was collected from the 

retroorbital sinus of as many as 15 male and 15 female anesthetized 

mice from each group designated for the determination of plasma 

concentrations of AZT at five time points (15, 30, 60, 90, or 120 

minutes after the first daily dose of AZT was administered); three mice 

from each group of 15 were evaluated at each time point. On the last 

day of the 2-year AZT study, blood was collected from the retroorbital 

sinus of 18 male and 18 female anesthetized mice from each core study 

dosed group at six time points (5, 15, 30, 60, 90, or 120 minutes after 

the first daily dose of AZT was administered); three mice from each 

group were evaluated at each time point. Additionally, on the last day 

of the study, blood was collected from five male and five female mice in 

the dosed core study groups before the first daily dose was 

administered. The mean plasma concentrations of AZT and standard 

deviations were calculated. 
38 AZT and AZT/"-Interferon A/D, NTP TR 469 

STATISTICAL METHODS 

Survival Analyses 

The probability of survival was estimated by the 

product-limit procedure of Kaplan and Meier (1958) 

and is presented in the form of graphs. Animals 

found dead of other than natural causes or missing 

were censored from the survival analyses; animals 

dying from natural causes were not censored. 

Statistical analyses for possible dose-related effects on 

survival used Cox’s (1972) method for testing 

two groups for equality and Tarone’s (1975) life table 

test to identify dose-related trends. All reported 

P values for the survival analyses are two sided. 

Calculation of Incidence 

The incidences of neoplasms or nonneoplastic lesions 

are presented in Tables A1, A4, B1, B4, C1, C3, D1, 

D4, E1, E3, F1, F3, G1, G3, H1, and H3 as the 

numbers of animals bearing such lesions at a specific 

anatomic site and the numbers of animals with that 

site examined microscopically. For calculation of 

statistical significance, the incidences of most neoplasms (Tables A2, B2, C2, D2, E2, F2, G2, and H2) 

and all nonneoplastic lesions are given as the numbers 

of animals affected at each site examined microscopically. However, when macroscopic examination 

was required to detect neoplasms in certain tissues 

(e.g., harderian gland, intestine, mammary gland, and 

skin) before microscopic evaluation, or when neoplasms had multiple potential sites of occurrence 

(e.g., leukemia or lymphoma), the denominators 

consist of the number of animals on which a necropsy 

was performed. Tables A2, B2, C2, D2, E2, F2, G2, 

and H2 also give the survival-adjusted neoplasm rate 

for each group and each site-specific neoplasm, i.e., 

the Kaplan-Meier estimate of the neoplasm incidence 

that would have been observed at the end of the study 

in the absence of mortality from all other competing 

risks (Kaplan and Meier, 1958). 

Analysis of Neoplasm Incidences 

The majority of neoplasms in these studies were considered to be incidental to the cause of death or not 

rapidly lethal. Thus, the primary statistical method 

used was logistic regression analysis, which assumed 

that the diagnosed neoplasms were discovered as the 

result of death from an unrelated cause and thus did 

not affect the risk of death. In this approach, neoplasm prevalence was modeled as a logistic function 

of chemical exposure and time. Both linear and quadratic terms in time were incorporated initially, and the 

quadratic term was eliminated if the fit of the model 

was not significantly enhanced. The neoplasm incidences of exposed and control groups were compared 

on the basis of the likelihood score test for the regression coefficient of dose. This method of adjusting 

for intercurrent mortality is the prevalence analysis of 

Dinse and Lagakos (1983), further described and 

illustrated by Dinse and Haseman (1986). When 

neoplasms are incidental, this comparison of the timespecific neoplasm prevalences also provides a comparison of the time-specific neoplasm incidences 

(McKnight and Crowley, 1984). 

In addition to logistic regression, other methods of 

statistical analysis were used, and the results of these 

tests are summarized in the appendixes. These methods include the life table test (Cox, 1972; Tarone, 

1975), appropriate for rapidly lethal neoplasms, and 

the Fisher exact test and the Cochran-Armitage trend 

test (Armitage, 1971; Gart et al., 1979), procedures 

based on the overall proportion of neoplasm-bearing 

animals. 

Tests of significance included pairwise comparisons of 

each dosed group with controls and a test for an overall dose-related trend. Continuity-corrected tests were 

used in the analysis of neoplasm incidence, and 

reported P values are one sided. The procedures described in the preceding paragraphs were also used to 

evaluate selected nonneoplastic lesions. For further 

discussion of these statistical methods, refer to 

Haseman (1984). 

Analysis of Nonneoplastic Lesion Incidences 

Because all nonneoplastic lesions in this study were 

considered to be incidental to the cause of death or not 

rapidly lethal, the primary statistical analysis used was 

a logistic regression analysis in which nonneoplastic 

lesion prevalence was modeled as a logistic function 

of chemical exposure and time. 

Analysis of Continuous Variables 

Two approaches were employed to assess the significance of pairwise comparisons between dosed and 

control groups in the analysis of continuous variables. 

Organ and body weight data, which have approximately normal distributions, were analyzed with the 

parametric multiple comparison procedures of Dunnett 

(1955) and Williams (1971, 1972). Hematology, 

bone marrow, spermatid, epididymal spermatozoal, 
AZT and AZT/"-Interferon A/D, NTP TR 469 39 

and neurobehavioral data, which have typically 

skewed distributions, were analyzed using the 

nonparametric multiple comparison methods of 

Shirley (1977) and Dunn (1964). Jonckheere’s test 

(Jonckheere, 1954) was used to assess the significance 

of the dose-related trends and to determine whether a 

trend-sensitive test (Williams’ or Shirley’s test) was 

more appropriate for pairwise comparisons than a test 

that does not assume a monotonic dose-related trend 

(Dunnett’s or Dunn’s test). Prior to statistical analysis, extreme values identified by the outlier test of 

Dixon and Massey (1951) were examined by NTP 

personnel, and implausible values were eliminated 

from the analysis. Average severity values were 

analyzed for significance with the Mann-Whitney U 

test (Hollander and Wolfe, 1973). Because vaginal 

cytology data are proportions (the proportion of the 

observation period that an animal was in a given 

estrous stage), an arcsine transformation was used to 

bring the data into closer conformance with a 

normality assumption. Treatment effects were investigated by applying a multivariate analysis of variance 

(Morrison, 1976) to the transformed data to test for 

simultaneous equality of measurements across dose 

levels. 

Historical Control Data 

Although the concurrent control group is always the 

first and most appropriate control group used for 

evaluation, historical control data can be helpful in the 

overall assessment of neoplasm incidence in certain 

instances. Consequently, neoplasm incidences from 

the NTP historical control database which is updated 

yearly are included in the NTP reports for neoplasms 

appearing to show compound-related effects. Because 

there are no methylcellulose gavage studies in the 

NTP historical control database, historical data from 

water gavage studies were used for comparison. 

Likewise, there are no subcutaneous studies in the 

NTP historical control database, so feed studies were 

used for comparison in that portion of the current 

studies. 

QUALITY ASSURANCE METHODS 

The 14-week and 2-year studies were conducted in 

compliance with Food and Drug Administration Good 

Laboratory Practice Regulations (21 CFR, Part 58). 

In addition, as records from the 2-year studies were 

submitted to the NTP Archives, these studies were 

audited retrospectively by an independent quality 

assurance contractor. Separate audits covered completeness and accuracy of the pathology data, 

pathology specimens, final pathology tables, and a 

draft of this NTP Technical Report. Audit procedures 

and findings are presented in the reports and are on 

file at NIEHS. The audit findings were reviewed and 

assessed by NTP staff, and all comments were 

resolved or otherwise addressed during the preparation of this Technical Report. 

GENETIC TOXICOLOGY 

The genetic toxicity of AZT was assessed by testing 

the ability of the chemical to induce mutations in 

various strains of Salmonella typhimurium, sister 

chromatid exchanges and chromosomal aberrations in 

cultured Chinese hamster ovary cells, and increases in 

the frequency of micronucleated erythrocytes in bone 

marrow and peripheral blood of mice. The protocols 

for these studies and the results are given in 

Appendix I. 

The genetic toxicity studies of AZT are part of a 

larger effort by the NTP to develop a database that 

would permit the evaluation of carcinogenicity in 

experimental animals from the molecular structure and 

the effects of the chemical in short-term in vitro and 

in vivo genetic toxicity tests. These genetic toxicity 

tests were originally developed to study mechanisms 

of chemical-induced DNA damage and to predict 

carcinogenicity in animals, based on the electrophilicity theory of chemical mutagenesis and the somatic 

mutation theory of cancer (Miller and Miller, 1977; 

Straus, 1981; Crawford, 1985). 

There is a strong correlation between a chemical’s 

potential electrophilicity (structural alert to DNA 

reactivity), mutagenicity in Salmonella, and carcinogenicity in rodents. The combination of electrophilicity and Salmonella mutagenicity is highly correlated 

with the induction of carcinogenicity in rats and mice 

and/or at multiple tissue sites (Ashby and Tennant, 

1991). Other in vitro genetic toxicity tests correlate 

less well with rodent carcinogenicity (Tennant et al., 

1987; Zeiger et al., 1990), although these other tests 

can provide information on the types of DNA and 

chromosome effects that can be induced by the 

chemical being investigated. Data from NTP studies 

show that a positive response in Salmonella is the 

most predictive in vitro test for rodent carcinogenicity 

(89% of the Salmonella mutagens are rodent carcino­
40 AZT and AZT/"-Interferon A/D, NTP TR 469 

gens), and that there is no complementarity among the 1995). Positive responses in long-term peripheral 

in vitro genetic toxicity tests. That is, no battery of blood micronucleus tests have not been formally 

tests that included the Salmonella test improved the evaluated for their predictivity for rodent carcinopredictivity of the Salmonella test alone. genicity. But, because of the theoretical and observed 

associations between induced genetic damage and 

The predictivity for carcinogenicity of a positive adverse effects in somatic and germ cells, the 

response in bone marrow chromosome aberration or determination of in vivo genetic effects is important to 

micronucleus tests appears to be less than the the overall understanding of the risks associated with 

Salmonella test (Shelby et al., 1993; Shelby and Witt, exposure to a particular chemical. 
 

41 

RESULTS
 

MICE 

14-WEEK AZT STUDY 

In the 14-week study, one female receiving week 1 due to gavage trauma (Table 6). Females 

100 mg/kg and two females receiving 200 mg/kg died receiving 200, 800, or 2,000 mg/kg gained less 

during week 1 as a result of gavage trauma; weight than the vehicle controls during the 14-week 

one female receiving 2,000 mg/kg also died prior to dosing period. The final mean body weights of dosed 

the end of the 14-week dosing period (Table 5). One mice were similar to those of the vehicle control 

female in the 2,000 mg/kg group in the 14-week groups at the end of the 14-week dosing period and at 

gavage with 4-week recovery study died during the end of the 4-week recovery period. 

TABLE 5 

Survival and Body Weights of Mice in the 14-Week Gavage Study of AZT 

Mean Body Weightb (g) Final Weight a Dose Survival Initial Final Change Relative to Controls 

(mg/kg) (%) 

Male 

0 10/10 23.0 ± 0.4 33.1 ± 0.5 10.1 ± 0.6 

50 10/10 23.0 ± 0.3 33.9 ± 0.6 10.9 ± 0.5 102 

100 10/10 22.8 ± 0.4 35.5 ± 1.0 12.7 ± 0.9* 107 

200 10/10 23.4 ± 0.5 34.6 ± 0.9 11.3 ± 0.5 105 

800 10/10 23.3 ± 0.4 34.0 ± 0.7 10.7 ± 0.7 103 

2,000 10/10 23.1 ± 0.4 32.4 ± 0.6 9.3 ± 0.3 98 

Female 

0 10/10 19.0 ± 0.9 28.9 ± 1.3 10.0 ± 1.2 

50 10/10 19.3 ± 0.5 28.6 ± 0.5 9.3 ± 0.5 99 c 100 9/10 18.8 ± 0.7 27.6 ± 0.4 8.1 ± 0.4 95 c 200 8/10 18.6 ± 0.9 27.2 ± 0.7 7.3 ± 0.5* 94 

800 10/10 19.6 ± 0.3 26.3 ± 0.6 6.7 ± 0.5* 91 

2,000 9/10d 19.1 ± 0.2 26.8 ± 1.0 7.8 ± 0.9* 93 

* Significantly different (P#0.05) from the vehicle control group by Williams’ or Dunnett’s test a Number of animals surviving at 14 weeks/number initially in group b Weights and weight changes are given as mean ± standard error. 

Week of death: 1 (gavage trauma) d Week of death: 9 

c 
 

42 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE 6 

Survival and Body Weights of Mice in the 14-Week Gavage with 4-Week Recovery Study of AZT 

Dose 

(mg/kg) 

Survivala Initial 

Mean Body Weight (g) b 

Final Change 

Final Weight 

Relative to Controls 

(%) 

Male 

0 

100 

800 

2,000 

10/10 

10/10 

10/10 

10/10 

23.4 ± 0.4 

23.2 ± 0.3 

23.7 ± 0.4 

22.9 ± 0.4 

37.2 ± 1.0 

38.8 ± 0.7 

38.3 ± 1.4 

36.1 ± 1.3 

13.7 ± 0.8 

15.6 ± 0.5 

14.6 ± 1.3 

13.3 ± 1.0 

104 

103 

97 

Female 

0 

100 

800 

2,000 

10/10 

10/10 

10/10 

9/10c 

19.9 ± 0.3 

19.7 ± 0.3 

20.0 ± 0.2 

19.6 ± 0.2 

30.8 ± 1.4 

32.3 ± 0.5 

32.8 ± 1.1 

30.1 ± 0.9 

10.9 ± 1.1 

12.6 ± 0.4 

12.8 ± 1.0 

10.4 ± 0.8 

105 

106 

98 

a Number of animals surviving at 17 weeks/number initially in group b Weights and weight changes are given as mean ± standard error. Differences from the vehicle control groups were not significant by 

Dunnett’s test. 

Week of death: 1 (gavage trauma) 

Clinical findings during the 14-week study included a macrocytic, nonresponsive anemia occurred in male 

chemical-related darkening of the skin on the tail, and female mice; these findings are consistent with the 

feet, and muzzle beginning around week 6. Darkened AZT-induced hematotoxicity reported previously for 

skin was also observed in dosed mice following the mice (Thompson et al., 1991). On day 5, decreased 

4-week recovery period, but it was limited to the tail erythrocyte counts occurred in 800 mg/kg female and 

and was less severe than that observed in dosed mice 2,000 mg/kg male and female mice. By day 23, 

at the end of the 14-week dosing period. erythrocyte counts were decreased in males administered 100 mg/kg or greater and in all dosed groups 

At the end of the 14-week dosing period, the absolute of females; at study termination, decreased erythroheart weight and the absolute and relative thymus cyte counts occurred in all dosed groups. Decreased 

weights of males receiving 50 mg/kg, the absolute left hematocrit values and hemoglobin concentrations also 

and right kidney weights of males receiving occurred in various dosed groups at all time points. 

200 mg/kg, and the absolute and relative liver weights There was no indication of an erythropoietic response 

of males receiving 50 or 200 mg/kg were significantly to the anemia, based on the lack of increased 

greater than those of the vehicle control group reticulocyte numbers; in fact, reticulocyte counts were 

(Table J1). The absolute right testis weight of males decreased in 200 mg/kg or greater male and female 

receiving 2,000 mg/kg and the absolute thymus mice on day 5 and in the 100 mg/kg or greater female 

weight of females receiving 2,000 mg/kg were signifi- and 800 mg/kg or greater male mice at week 14. The 

cantly lower than those of the vehicle control groups. erythrocytes were macrocytic, evidenced by increased 

At the end of the recovery period, the absolute heart mean cell volume and mean cell hemoglobin in all 

weight of males receiving 800 mg/kg was significantly dosed groups on day 23 and at study termination; a 

greater than that of the vehicle control group. macrocytosis, without an increase of reticulocyte 

counts, would be consistent with an effective erythroThe hematology and bone marrow data for mice in the poiesis. An erythroid hypoplasia in the bone marrow, 

14-week study are listed in Table K1. In general, a evidenced by decreased total femur counts and 

dose- and time-dependent, minimal to moderate, erythroid precursor (rubricyte and metarubri­
 

AZT and AZT/"-Interferon A/D, NTP TR 469 43 

cyte) numbers and increased M:E ratios, occurred At the end of the 14-week dosing period, bone marin males administered 800 mg/kg or greater and in row atrophy in males receiving 2,000 mg/kg and 

females receiving 100 mg/kg or greater; the bone females receiving 800 or 2,000 mg/kg and splenic 

marrow results support the decreased reticulocyte hematopoietic cell proliferation in males and females 

counts in the peripheral blood. Bone marrow receiving 200, 800, or 2,000 mg/kg were considered 

lymphocyte (2,000 mg/kg males and 100 mg/kg or chemical related. No chemical-related lesions were 

greater females), metamyelocyte, band, segmented observed at the end of the recovery period. 

neutrophil, and monocyte counts (100 mg/kg and 

greater females) also decreased; these decreases also 

would have contributed to the decreased total femur 

counts. Increased platelet counts occurred on day 23 

in males administed 800 mg/kg or greater and in Dose Selection Rationale: The only significant toxic 

females receiving 100 mg/kg or greater, and in response associated with AZT treatment was a poorly 

2,000 mg/kg males at week 14. Increased platelet regenerative, normochromic, macrocytic anemia 

counts were not associated with increased numbers of which increased in severity with increasing dose 

megakaryocytes in the bone marrow and would be concentration but was present to some extent in 

consistent with evidence in humans that increased animals at each dose concentration. A no-effect level 

platelet counts are related to enhanced platelet survival was not achieved in the 14-week study, and because 

(Panzer et al., 1989). The data from the recovery of the potentially cumulative nature of bone marrow 

portion of the 14-week study indicate that AZT- toxicity in the presence of daily exposure to AZT, it 

induced hematotoxicity is reversible. At the end of was considered desirable to include a dose below 

the 4-week recovery period the macrocytic anemia 50 mg/kg in the 2-year study. At doses of 200 mg/kg 

had ameliorated. Additionally, platelet and bone and greater the severity of anemia was considered to 

marrow variable counts of dosed animals returned to be potentially life threatening in a 2-year study, 

control values. whereas the response at 100 mg/kg was similar to that 

observed at 50 mg/kg and was considered somewhat 

There were no consistent treatment-related effects low for the high dose in a 2-year study. Therefore, 

on reproductive (Table L1) or neurobehavioral total daily doses selected for the 2-year AZT study 

parameters (Table M1) evaluated during the 14-week were 30, 60, and 120 mg/kg to be administered by 

study. gavage as twice-daily doses of 15, 30, and 60 mg/kg. 
 

44 AZT and AZT/"-Interferon A/D, NTP TR 469 

2-YEAR AZT STUDY 

Survival 

Estimates of 2-year survival probabilities for male and 

female mice are shown in Table 7 and in the KaplanMeier survival curves (Figure 1). Males receiving 

120 mg/kg had a significantly greater probability of 

survival than the vehicle control group; survival of all 

other groups of dosed mice was similar to that of the 

vehicle control groups. 

Body Weights and Clinical Findings 

Mean body weights of dosed groups of mice were 

similar to those of the vehicle control groups throughout the study (Tables 8 and 9; Figure 2). There were 

no chemical-related clinical findings. 

TABLE 7 

Survival of Mice in the 2-Year Gavage Study of AZT 

Hematology and Bone Marrow Analyses 

The hematology and bone marrow data for mice in the 

2-year study of AZT are listed in Table K2. In general, a dose- and time-dependent, minimal to mild, 

macrocytic, nonresponsive anemia occurred in all 

dosed mice; these findings were consistent with the 

AZT-induced hematotoxicity reported for mice in the 

14-week study. At week 80, macrocytic anemia was 

resolved in 30 mg/kg males; at study termination, 

only erythrocytic macrocytosis occurred in 60 and 

120 mg/kg males. Macrocytic anemia was observed 

in all dosed groups of female mice throughout the 

study. 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Male 

Animals initially in study	 50 50 50 50 

Accidental deathsa 0 0 3 0 

Moribund 6 9 9 4 

Natural deaths 12 6 9 4 

Animals surviving to study termination 32 35 29 42 

Percent probability of survival at end of studyb 64 70 62 84 c Mean survival (days)	 684 679 647 710 

Survival analysisd	 P=0.054N P=0.674N P=0.905 P=0.044N 

Female 

Animals initially in study	 50 50 50 50 

Accidental deathsa 0 0 3 1 

Moribund 5 5 9 7 

Natural deaths 11 6 7 11 e Animals surviving to study termination 34 39 31 31 

Percent probability of survival at end of study 68 78 66 63 

Mean survival (days) 689 707 648 687 

Survival analysis	 P=0.499 P=0.360N P=0.971 P=0.874 

a Censored from survival analyses b	 Kaplan-Meier determinations 

Mean of all deaths (uncensored, censored, and terminal sacrifice) d	 The result of the life table trend test (Tarone, 1975) is in the vehicle control column, and the results of the life table pairwise comparisons 

(Cox, 1972) with the vehicle controls are in the dosed group columns. A negative trend or lower mortality in a dosed group is indicated by 

N. e Includes one animal that died during the last week of the study 

c 
 

AZT and AZT/"-Interferon A/D, NTP TR 469 45 

FIGURE 1
 

Kaplan-Meier Survival Curves for Male and Female Mice 

Administered AZT in Methylcellulose by Gavage for 2 Years
 
 

46 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE 8 

Mean Body Weights and Survival of Male Mice in the 2-Year Gavage Study of AZT 

Weeks Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

on Av. Wt. No. of Av. Wt. Wt. (% of No. of Av. Wt. Wt. (% of No. of Av. Wt. Wt. (% of No. of 

Study (g) Survivors (g) controls) Survivors (g) controls) Survivors (g) controls) Survivors 

1 25.6 50 25.5 100 50 25.6 100 49 25.4 99 50 

2 27.0 50 27.1 100 50 27.2 101 49 27.1 100 50 

3 28.0 50 27.9 100 50 27.9 100 49 27.7 99 50 

4 29.2 50 28.9 99 50 29.3 100 49 29.0 99 50 

5 29.7 50 29.4 99 50 29.7 100 49 29.4 99 50 

6 30.6 50 30.5 100 50 30.8 101 49 30.3 99 50 

7 31.5 50 31.4 100 50 31.7 101 49 31.3 99 50 

8 32.4 50 32.2 99 50 32.5 100 49 32.1 99 50 

9 32.9 50 32.7 99 50 33.0 100 49 32.8 100 50 

10 33.4 50 33.2 99 50 33.3 100 49 33.1 99 50 

11 33.8 50 34.1 101 50 34.5 102 49 33.8 100 50 

12 35.4 50 35.5 100 50 35.7 101 49 35.1 99 50 

13 34.0 50 34.0 100 50 34.3 101 49 33.6 99 50 

17 39.0 50 39.0 100 50 39.2 101 49 38.7 99 50 

21 42.1 50 41.6 99 50 42.6 101 49 41.4 98 50 

25 44.2 50 44.1 100 50 44.4 101 49 43.7 99 50 

30 46.4 50 45.9 99 50 46.1 99 49 45.4 98 50 

33 46.8 50 46.8 100 50 47.3 101 49 46.5 99 50 

37 47.9 50 47.7 100 50 48.0 100 48 47.7 100 50 

41 49.1 50 48.7 99 49 49.3 100 48 48.8 99 50 

45 48.9 50 48.8 100 49 49.0 100 47 48.8 100 50 

49 49.3 49 48.7 99 49 49.4 100 47 49.3 100 50 

53 50.2 49 49.5 99 47 50.0 100 47 50.1 100 50 

57 49.8 49 49.5 99 47 49.5 99 46 50.0 100 50 

61 49.5 49 49.3 100 47 49.0 99 45 49.5 100 50 

65 50.1 48 49.6 99 47 49.4 99 45 50.3 100 50 

69 50.0 47 49.7 99 46 48.7 97 44 49.8 100 50 

73 50.2 47 49.9 99 45 48.8 97 42 49.8 99 50 

77 49.9 47 49.8 100 45 48.7 98 42 49.8 100 49 

81 49.2 47 49.2 100 45 47.7 97 41 49.7 101 47 

85 48.9 43 48.6 99 43 47.5 97 39 49.8 102 46 

89 48.2 41 47.5 99 43 46.1 96 38 49.3 102 45 

93 47.4 38 46.3 98 41 45.3 96 35 48.6 103 45 

97 46.2 38 45.8 99 38 44.4 96 33 47.3 102 45 

101 45.3 34 45.0 99 38 44.2 98 31 47.5 105 42 

Mean for weeks 

1-13 31.0 31.0 100 31.2 101 30.8 99 

14-52 46.0 45.7 99 46.1 100 45.6 99 

53-101 48.8 48.4 99 47.6 98 49.3 101 
 

AZT and AZT/"-Interferon A/D, NTP TR 469 47 

TABLE 9 

Mean Body Weights and Survival of Female Mice in the 2-Year Gavage Study of AZT 

Weeks Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

on Av. Wt. No. of Av. Wt. Wt. (% of No. of Av. Wt. Wt. (% of No. of Av. Wt. Wt. (% of No. of 

Study (g) Survivors (g) controls) Survivors (g) controls) Survivors (g) controls) Survivors 

1 20.4 50 20.2 99 50 20.7 102 49 20.6 101 49 

2 22.2 50 22.0 99 50 22.1 100 49 22.3 101 49 

3 23.0 50 23.3 101 50 23.4 102 49 23.4 102 49 

4 23.9 50 24.2 101 50 24.3 102 49 24.2 101 49 

5 24.8 50 24.8 100 50 25.2 102 49 25.2 102 49 

6 25.7 50 26.0 101 50 26.5 103 49 26.4 103 49 

7 26.6 50 26.9 101 50 27.2 102 49 27.4 103 49 

8 27.1 50 27.4 101 50 27.5 102 49 27.8 103 49 

9 27.9 50 28.3 101 50 28.4 102 49 28.7 103 49 

10 28.2 50 28.8 102 50 29.1 103 49 29.1 103 49 

11 28.6 50 29.6 104 50 29.8 104 49 30.0 105 49 

12 29.1 50 30.2 104 50 30.5 105 49 30.2 104 49 

13 29.5 50 30.0 102 50 30.3 103 48 30.3 103 49 

17 34.0 50 34.6 102 50 34.6 102 48 34.7 102 49 

21 37.1 50 38.0 102 50 37.9 102 48 37.5 101 49 

25 39.8 50 40.1 101 50 40.3 101 48 40.2 101 49 

29 42.1 50 42.7 101 50 42.6 101 48 42.4 101 49 

33 44.1 50 44.5 101 50 44.5 101 47 44.8 102 49 

37 46.4 50 47.2 102 50 46.7 101 47 47.5 102 49 

41 48.6 50 49.0 101 50 48.8 100 47 49.2 101 49 

45 50.2 50 51.2 102 50 50.7 101 45 50.8 101 49 

49 51.7 50 52.8 102 50 52.2 101 45 52.2 101 49 

53 53.2 50 54.6 103 50 54.0 102 45 54.2 102 49 

57 54.2 49 55.3 102 50 54.3 100 45 54.6 101 49 

61 54.3 48 55.6 102 50 54.0 99 45 55.6 102 49 

65 55.1 48 56.4 102 50 54.8 100 45 56.3 102 49 

69 55.2 47 57.1 103 50 54.8 99 45 56.0 101 48 

73 56.1 47 57.6 103 50 55.4 99 44 57.0 102 47 

77 57.3 45 57.6 101 48 56.1 98 43 57.5 100 47 

81 58.0 45 57.8 100 48 56.1 97 42 58.3 101 46 

85 57.7 45 56.7 98 47 55.6 96 41 58.0 101 46 

89 57.0 42 57.3 101 45 57.5 101 38 57.9 102 43 

93 55.8 41 56.5 101 43 57.0 102 38 57.4 103 42 

97 55.2 39 55.2 100 41 55.5 101 36 55.3 100 41 

101 53.8 37 55.4 103 39 55.5 103 33 55.1 102 37 

Mean for weeks 

1-13 25.9 26.3 102 26.5 102 26.6 103 

14-52 43.8 44.5 102 44.3 101 44.4 101 

53-101 55.6 56.4 101 55.4 100 56.4 101 
 

48 AZT and AZT/"-Interferon A/D, NTP TR 469 

FIGURE 2
 

Growth Curves for Male and Female Mice 

Administered AZT in Methylcellulose by Gavage for 2 Years
 
 

AZT and AZT/"-Interferon A/D, NTP TR 469 49 

Determinations of AZT Concentrations 

in Plasma 

Mean plasma concentrations of AZT were determined 

at week 54 and at the end of the study and are presented in Table N1. At week 54, peak plasma concentrations of all dosed groups of males and 30 and 

60 mg/kg females occurred at the earliest time point 

evaluated (15 minutes), with peak concentrations in 

females approximately twice the corresponding values 

in males. In females receiving 120 mg/kg, the peak 

plasma concentration occurred at 30 minutes; however, there was significant variation of the three individual values at this time point as reflected by the 

large standard deviation. In males and females, peak 

concentrations increased in a dose-proportional 

manner at week 54. 

At the end of the study, peak plasma AZT concentrations exhibited considerably more variation, with 

peak concentrations occurring 5 to 30 minutes after 

dosing. In general, peak values of females were 

similar to those of males. 
 

 

50 AZT and AZT/"-Interferon A/D, NTP TR 469 

Pathology and Statistical Analysis 

This section describes the statistically significant or 

biologically noteworthy changes in the incidences of 

neoplasms and/or nonneoplastic lesions of the vagina, 

kidney, harderian gland, liver, adrenal gland, and 

bone marrow. Summaries of the incidences of neoplasms and nonneoplastic lesions, statistical analyses 

of primary neoplasms that occurred with an incidence 

of at least 5% in at least one animal group, and 

historical incidences for the neoplasms mentioned in 

this section are presented in Appendix A for male 

mice and Appendix B for female mice. 

Vagina: The incidences of squamous cell carcinoma 

and squamous cell papilloma or carcinoma (combined) 

occurred with a positive trend and were significantly 

increased in groups of female mice receiving 60 or 

120 mg/kg (Tables 10 and B2). Epithelial hyperplasia 

was observed in all dosed groups of females but not in 

the vehicle controls; the incidence was significantly 

increased in the 120 mg/kg group (Tables 10 and B4). 

Squamous cell carcinomas were typically keratinizing 

proliferations of anaplastic cells that usually protruded 

into the lumen and infiltrated into the submucosa and 

smooth muscle of the vagina (Plate 1). Squamous cell 

papillomas protruded but did not invade underlying 

tissue (Plate 2). The proliferating cells of the papillomas were uniform in size and shape, and their arrangement was more ordered and consistent than that 

of the carcinomas. Epithelial hyperplasia was a focal 

to multifocal nodular thickening of the basal and 

middle layers of epithelium (Plate 3). Atypical hyperplasia consisted of focal to multifocal thickening of 

epithelial cells that were somewhat variable in size 

and shape (Plate 4). 

TABLE 10 

Incidences of Neoplasms and Nonneoplastic Lesions of the Vagina in Female Mice 

in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Number Examined Microscopically 50 49 45 49 

Epithelium, Hyperplasiaa 0 3 (1.0)b 2 (2.0) 7** (2.3) 

Epithelium, Hyperplasia, Atypical 0 0 2 (3.0) 4 (2.3) 

Squamous Cell Papilloma c Overall rate	 0/50 (0%) 0/49 (0%) 0/45 (0%) 2/49 (4%) 

Squamous Cell Carcinoma 

Overall rate 0/50 (0%) 0/49 (0%) 5/45 (11%) 9/49 (18%) 

Adjusted rated 0.0% 0.0% 12.8% 26.8% e Terminal rate 0/34 (0%) 0/39 (0%) 1/30 (3%) 7/31 (23%) 

First incidence (days) —g — 493 695 

Logistic regression testf P<0.001 — P=0.028 P=0.002 

Squamous Cell Papilloma or Squamous Cell Carcinoma 

Overall rate 0/50 (0%) 0/49 (0%) 5/45 (11%) 11/49 (22%) 

Adjusted rate 0.0% 0.0% 12.8% 32.9% 

Terminal rate 0/34 (0%) 0/39 (0%) 1/30 (3%) 9/31 (29%) 

First incidence (days) — — 493 695 

Logistic regression test P<0.001 — P=0.028 P<0.001 

** Significantly different (P#0.01) from the vehicle control group by the logistic regression test a	 Number of animals with lesion 

b	 Average severity grade of lesions in affected animals: 1=minimal, 2=mild, 3=moderate, 4=marked 

Number of neoplasm-bearing animals/number of animals microscopically examined d	 Kaplan-Meier estimated neoplasm incidence at the end of the study after adjustment for intercurrent mortality e	 Observed incidence at terminal kill 

f	 Beneath the vehicle control incidence are the P values associated with the trend test. Beneath the dosed group incidence are the P values 

corresponding to pairwise comparisons between the vehicle controls and that dosed group. The logistic regression test regards neoplasms in 

animals dying prior to terminal kill as nonfatal. g	 Not applicable; no neoplasms in animal group 

c 
 

AZT and AZT/"-Interferon A/D, NTP TR 469 51 

Kidney: During histological examination of the stan- however, five additional renal tubule hyperplasias 

dard kidney sections, three renal tubule adenomas and were observed in 60 mg/kg males and six additional 

one renal tubule carcinoma were observed in hyperplasias were observed in 120 mg/kg males. 

120 mg/kg males and one renal tubule hyperplasia 

was observed in a 30 mg/kg male (Tables 11, A1, A2, Renal tubule adenomas consisted of multiple disand A4). The incidences of adenoma and of adenoma organized layers of epithelium forming solid or 

or carcinoma (combined) exceeded the range in tubular structures that compressed adjacent tissue. 

historical controls (Table A3a). Evaluation of step The renal tubule carcinoma was larger and had more 

sections did not reveal any additional neoplasms; structural disorganization and cellular anaplasia than 

TABLE 11 

Incidences of Neoplasms and Nonneoplastic Lesions of the Kidney in Male Mice 

in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Single Sections (Standard Evaluation) 

Number Examined Microscopically 

Renal Tubule Hyperplasia, Focala 50 0 

48 

1 (2.0)b 

49 

0 

50 

0 

Renal Tubule Adenomac 

Overall rated 0/50 (0%) 0/48 (0%) 0/49 (0%) 3/50 (6%) 

Renal Tubule Carcinoma 

Overall rate 0/50 (0%) 0/48 (0%) 0/49 (0%) 1/50 (2%) 

Renal Tubule Adenoma or Carcinomae 

Overall rate 

Adjusted ratef 

Terminal rateg 

First incidence (days) 

Logistic regression testh 

0/50 (0%) 

0.0% 

0/32 (0%) 

—i 

P=0.007 

0/48 (0%) 

0.0% 

0/35 (0%) 

— 

— 

0/49 (0%) 

0.0% 

0/29 (0%) 

— 

— 

4/50 (8%) 

9.5% 

4/42 (10%) 

729 (T) 

P=0.103 

Step Sections (Extended Evaluation) 

Number Examined Microscopically 

Renal Tubule Hyperplasia 

50 

0 

—j 50 

5* (1.0) 

50 

6* (1.0) 

Single and Step Sections (Combined) 

Number Examined Microscopically 

Renal Tubule Hyperplasia 

50 

0 

48 

1 (2.0) 

50 

5* (1.0) 

50 

6* (1.0) 

(T)Terminal sacrifice 

* Significantly different (P#0.05) from the vehicle control group by the logistic regression test a Number of animals with lesion 

b Average severity grade of lesions in affected animals: 1=minimal, 2=mild, 3=moderate, 4=marked c Historical incidence for 2-year NTP gavage studies with water vehicle control groups: 0/365 d Number of neoplasm-bearing animals/number of animals microscopically examined e Historical incidence (mean ± standard deviation): 2/365 (0.6% ± 1.5%); range, 0%-4% f Kaplan-Meier estimated neoplasm incidence at the end of the study after adjustment for intercurrent mortality g Observed incidence at terminal kill 

h	 Beneath the vehicle control incidence are the P values associated with the trend test. Beneath the dosed group incidence are the P values 

corresponding to pairwise comparisons between the vehicle controls and that dosed group. The logistic regression test regards neoplasms in 

animals dying prior to terminal kill as nonfatal. i	 Not applicable; no neoplasms in animal group j Not examined at this dose level 
 

52 AZT and AZT/"-Interferon A/D, NTP TR 469 

the adenomas. Renal tubule hyperplasia consisted of mice receiving 30 mg/kg, but none were observed in 

tubules with stratified epithelium rather than the vehicle controls or other dosed groups. The incinormal single layer of epithelium. dences of harderian gland neoplasms were not increased in groups of female mice (Tables 12, B1, and 

B2). Hyperplasia was present in one male receiving 

Harderian Gland: The incidence of harderian gland 30 mg/kg (Table A4). Harderian gland adenomas 

adenoma was increased in 120 mg/kg males and were papillary, acinar, or cystic formations of slightly 

exceeded the range in historical controls (Tables 12, pleomorphic epithelial cells that compressed adjacent 

A2, and A3b). Carcinomas occurred in three male tissue. 

TABLE 12 

Incidences of Neoplasms of the Harderian Gland in Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Male 

Adenomaa 

Overall rateb 

Adjusted ratec 

Terminal rated 

First incidence (days) 

Logistic regression teste 

3/50 (6%) 

9.4% 

3/32 (9%) 

729 (T) 

P=0.009 

2/50 (4%) 

5.7% 

2/35 (6%) 

729 (T) 

P=0.459N 

2/50 (4%) 

6.3% 

1/29 (3%) 

667 

P=0.546N 

10/50 (20%) 

23.1% 

9/42 (21%) 

612 

P=0.059 

Carcinoma 

Overall rate 0/50 (0%) 3/50 (6%) 0/50 (0%) 0/50 (0%) 

Adenoma or Carcinoma 

Overall rate 

Adjusted rate 

Terminal rate 

First incidence (days) 

Logistic regression test 

3/50 (6%) 

9.4% 

3/32 (9%) 

729 (T) 

P=0.027 

5/50 (10%) 

13.3% 

4/35 (11%) 

458 

P=0.355 

2/50 (4%) 

6.3% 

1/29 (3%) 

667 

P=0.546N 

10/50 (20%) 

23.1% 

9/42 (13%) 

612 

P=0.059 

Female 

Adenoma 

Overall rate 4/50 (8%) 2/50 (4%) 0/50 (0%) 1/50 (2%) 

Carcinoma 

Overall rate 1/50 (2%) 0/50 (0%) 1/50 (2%) 1/50 (2%) 

Adenoma or Carcinoma 

Overall rate 5/50 (10%) 2/50 (4%) 1/50 (2%) 2/50 (4%) 

(T)Terminal sacrifice 

a Historical incidence for 2-year NTP gavage studies with water vehicle control groups (mean ± standard deviation): 18/365 (4.9% ± 3.5%); 

range, 2%-10% b	 Number of neoplasm-bearing animals/number of animals necropsied 

Kaplan-Meier estimated neoplasm incidence at the end of the study after adjustment for intercurrent mortality d Observed incidence at terminal kill e Beneath the vehicle control incidence are the P values associated with the trend test. Beneath the dosed group incidence are the P values 

corresponding to pairwise comparisons between the vehicle controls and that dosed group. The logistic regression test regards neoplasms in 

animals dying prior to terminal kill as nonfatal. A lower incidence in a dosed group is indicated by N. 

c 
 

AZT and AZT/"-Interferon A/D, NTP TR 469 53 

Liver: The incidence of hepatoblastoma was increased between vehicle control and treated groups. 

in males receiving 60 mg/kg, but not in the 30 or Therefore, the slight increase in the incidence of 

120 mg/kg groups (Tables 13 and A2). Hepato- hepatoblastoma in the 60 mg/kg group was not conblastomas are uncommon neoplasms, which occur sidered related to administration of AZT. 

spontaneously or may be chemically induced in the 

liver of several strains of mice including B6C3F1 The incidence of hepatocellular adenoma, hepato­

(Turusov et al., 1973; Nonoyama et al., 1988). It is cellular carcinoma, or hepatoblastoma (combined) was 

considered a malignant neoplasm and in NTP studies, significantly greater in females receiving 120 mg/kg 

its metastatic potential appears similar to that of than in the vehicle control group (Tables 13 and B2). 

hepatocellular carcinomas. Hepatoblastomas are The increase was primarily of benign neoplasms 

easily diagnosed because of their distinctive morphol- (adenomas), and potentially preneoplastic foci of 

ogy on H&E-stained sections. They almost always alteration were not different between the vehicle 

occur within an existing proliferative lesion, most control and 120 mg/kg group (Table B4). An 

often within a hepatocellular carcinoma. In NTP increase was not observed in male mice in this 

studies, the diagnosis of hepatoblastoma is made study, and there is no evidence of increases in liver 

whenever this distinctive lesion is observed. To avoid neoplasms observed in the companion studies in 

duplicate diagnoses, a separate diagnosis for the lesion which similar amounts of AZT were administered. 

within which the hepatoblastoma occurs is not made. This marginal increase of a very common neoplasm 

type was not considered related to administration 

The cell of origin of the hepatoblastoma has not been of AZT. 

clearly defined in rodents or humans, but may be a 

very primordial cell (Abenoza et al., 1987; Nonoyama Relatively high incidences of chronic inflammation 

et al., 1988; Van Eyken et al., 1990). To fully and hepatocyte karyomegaly occurred in all groups of 

appreciate the significance of a potentially chemical- male mice; these lesions were usually observed 

related increase in neoplasms, the NTP generally together in the same liver (Tables 13 and A4). 

performs statistical analyses on benign and malignant Chronic inflammation was characterized by oval cell 

neoplasms of like histogenesis both independently and hyperplasia, minimal to mild mononuclear inflammain combination. Although the biology is not fully tory cell infiltrates, and, in more severe lesions, noduunderstood, hepatoblastoma is considered to be part of lar regenerative hepatocellular hyperplasia. These 

the spectrum of neoplastic liver lesions that occur both changes were generally mild to moderate in severity 

spontaneously and as a result of chemical treatment. and observed throughout the liver (usually not within 

Therefore, the NTP considers the combinations of proliferative lesions), but they appeared most prohepatocellular carcinoma plus hepatoblastoma and nounced in the portal regions. Similar lesions were 

hepatocellular adenoma and carcinoma plus hepato- observed in very few females, and the severity was 

blastoma the most important for analyses of the also less than that observed in many males (Tables 13 

carcinogenic potential of an agent on the liver. In this and B4). Liver sections from only one of five male 

study of AZT, the incidences of all malignant hepato- mice with liver lesions appeared positive for bacterial 

cellular neoplasms (carcinomas and hepatoblastomas) organisms consistent with Helicobacter when 

and all hepatocellular neoplasms (adenomas, carci- examined using Steiner’s modification of the Warthinnomas, and hepatoblastomas) were not different Starry silver stain (Appendix R). 
 

54 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE 13 

Incidences of Neoplasms and Nonneoplastic Lesions of the Liver in Mice 

in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Male 

Number Examined Microscopically 

Chronic Inflammationa 

Hepatocyte, Karyomegaly 

50 

17 

7 

(1.9)b 

(2.3)

50 

24 

10 

(1.9) 

(2.3) 

50 

24 (1.8) 

15* (2.3) 

50 

16 

5 

(2.1) 

(1.8) 

Hepatocellular Adenoma 

Hepatocellular Carcinoma 

Hepatoblastoma 

Hepatocellular Adenoma, 

Hepatocellular Carcinoma,

 or Hepatoblastoma 

25 

21 

1 

36 

23 

26 

2 

39 

23 

22 

6* 

36 

26 

19 

2 

39 

Female 

Number Examined Microscopically 

Chronic Inflammation 

Hepatocyte, Karyomegaly 

Necrosis, Focal 

50 

1 

1 

3 

(2.0) 

(2.0) 

(2.7) 

50 

2 

1 

3 

(1.0) 

(2.0) 

(2.7) 

50 

2 

0 

2 

(1.0) 

(1.5) 

50 

1 

0 

10* 

(2.0) 

(2.5) 

Hepatocellular Adenomac 

Hepatocellular Carcinomad 

Hepatoblastoma 

Hepatocellular Adenoma, 

Hepatocellular Carcinoma, 

or Hepatoblastomae 

20 

12 

1 

27 

18 

17 

0 

29 

17 

11 

0 

23 

28 

15 

2 

36* 

* Significantly different (P#0.05) from the vehicle control group by the logistic regression test a Number of animals with lesion 

b Average severity grade of lesions in affected animals: 1=minimal, 2=mild, 3=moderate, 4=marked 

Historical incidence for 2-year NTP gavage studies with water vehicle control groups (mean ± standard deviation): 28/366 (7.7% ± 9.8%); 

range, 2%-29% d Historical incidence: 16/366 (4.4% ± 5.4%); range, 0%-16% e Historical incidence: 43/366 (11.8% ± 14.2%); range, 2%-43% 

Other Organs: The incidence of adrenal cortex focal tive trend. The incidence of bone marrow hyperplasia 

cytoplasmic alteration in males receiving 120 mg/kg in females receiving 120 mg/kg was significantly 

was significantly greater than that in the vehicle greater than that in the vehicle control group (1/50, 

control group (5/50, 11/49, 8/49, 18/49; Table A4), 3/49, 3/50, 7/50; Table B4), and the incidences of 

and the incidences of this lesion occurred with a posi- hyperplasia occurred with a positive trend. 
 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 55 

2-YEAR "-INTERFERON A/D STUDY 

Survival	 Body Weights and Clinical Findings 

Estimates of 2-year survival probabilities for male and Mean body weights of dosed males and females were 

female mice are shown in Table 14 and in the Kaplan- generally similar to those of the vehicle control groups 

Meier survival curves (Figure 3). Survival of dosed throughout the study (Figure 4; Tables 15 and 16). 

mice was similar to that of the vehicle control groups. There were no chemical-related clinical findings. 

Hematology and Bone Marrow Analyses 

There were no treatment-related alterations in hematology or bone marrow parameters (Table K3). 

TABLE 14 

Survival of Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Male 

Animals initially in study	 50 50 50 50 

Accidental deatha 0 0 0 1 

Moribund 13 10 7 10 

Natural deaths 10 13 15 11 

Animals surviving to study termination 27 27 28 28 

Percent probability of survival at end of studyb 54 54 56 57 c Mean survival (days)	 679 683 666 664 

Survival analysisd	 P=0.929N P=1.000N P=0.973 P=1.000N 

Female 

Animals initially in study	 50 50 50 50 

Accidental deatha 0 0 0 1 

Moribund 13 11 13 9 

Natural deaths 12 8 5 15 

Animals surviving to study termination 25 31 32 25 

Percent probability of survival at end of study 50 62 64 51 

Mean survival (days) 684 674 703 653 

Survival analysis	 P=0.471 P=0.417N P=0.174N P=1.000 

a Censored from survival analyses b	 Kaplan-Meier determinations 

Mean of all deaths (uncensored, censored, and terminal sacrifice) d	 The result of the life table trend test (Tarone, 1975) is in the vehicle control column, and the results of the life table pairwise comparisons 

(Cox, 1972) with the vehicle controls are in the dosed group columns. The "-interferon A group was excluded from the trend test. A 

negative trend or lower mortality in a dosed group is indicated by N. 

c 
 

56 AZT and AZT/"-Interferon A/D, NTP TR 469 

FIGURE 3
 

Kaplan-Meier Survival Curves for Male and Female Mice 

Administered "-Interferon A/D or A Subcutaneously for 2 Years
 
 

AZT and AZT/"-Interferon A/D, NTP TR 469 57 

FIGURE 4
 

Growth Curves for Male and Female Mice 

Administered "-Interferon A/D or A Subcutaneously for 2 Years
 
 

58 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE 15 

Mean Body Weights and Survival of Male Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

Weeks Vehicle Control 5,000 U "-IFN A 500 U "-IFN A/D 5,000 U "-IFN A/D 

on Av. Wt. No. of Av. Wt. Wt. (% of No. of Av. Wt. Wt. (% of No. of Av. Wt. Wt. (% of No. of 

Study (g) Survivors (g) controls) Survivors (g) controls) Survivors (g) controls) Survivors 

1 25.5 50 25.3 99 50 25.8 101 50 25.8 101 50 

2 27.6 50 27.3 99 50 27.5 100 50 27.6 100 50 

3 28.3 50 27.8 98 50 28.1 99 50 28.5 101 50 

4 28.9 50 28.5 99 50 29.0 100 50 29.2 101 50 

5 30.4 50 30.2 99 50 30.7 101 50 30.5 100 50 

6 31.6 50 31.3 99 50 31.6 100 50 31.9 101 50 

7 32.3 50 32.2 100 50 32.5 101 50 32.8 102 50 

8 33.5 50 33.2 99 50 33.3 99 50 33.6 100 50 

9 34.3 50 33.9 99 50 34.1 99 50 34.5 101 50 

10 34.1 50 34.0 100 50 33.6 99 50 34.7 102 50 

11 34.7 50 34.1 98 50 34.4 99 50 35.1 101 50 

12 36.8 50 36.4 99 50 36.4 99 50 36.8 100 50 

17 39.6 50 39.4 100 50 39.1 99 50 39.9 101 50 

20 42.4 50 42.3 100 50 42.6 101 50 42.9 101 49 

24 44.3 50 43.8 99 50 44.3 100 50 44.5 101 49 

28 45.8 50 45.8 100 50 46.3 101 50 46.3 101 49 

32 46.3 50 46.3 100 50 46.5 100 50 47.1 102 49 

36 48.4 50 47.9 99 50 48.4 100 50 48.7 101 49 

40 49.3 50 48.6 99 50 49.0 99 50 49.9 101 49 

44 49.2 50 48.9 99 50 48.6 99 50 50.1 102 49 

48 49.8 50 49.4 99 50 49.4 99 50 50.4 101 49 

52 49.2 50 48.8 99 50 49.4 100 50 49.8 101 49 

56 49.3 50 48.0 97 50 48.6 99 50 49.6 101 49 

60 50.0 49 50.0 100 50 49.3 99 49 50.6 101 49 

64 50.1 49 50.1 100 50 49.9 100 49 51.2 102 48 

68 51.1 48 50.4 99 50 49.6 97 49 51.9 102 48 

72 50.9 47 50.0 98 50 49.6 97 48 52.0 102 47 

76 49.8 47 49.4 99 48 49.4 99 47 51.7 104 46 

80 48.8 47 48.8 100 45 49.1 101 42 51.0 105 45 

84 47.2 44 48.6 103 42 49.5 105 38 50.6 107 39 

88 46.4 41 47.2 102 40 47.1 102 36 49.8 107 37 

92 46.5 38 46.6 100 39 47.2 102 34 48.9 105 35 

96 44.6 35 45.7 103 36 46.9 105 29 47.8 107 33 

100 44.9 30 45.4 101 32 45.6 102 29 47.8 107 29 

Mean for weeks 

1-13 31.5 31.2 99 31.4 100 31.8 101 

14-52 46.4 46.1 99 46.4 100 47.0 101 

53-100 48.3 48.4 100 48.5 100 50.2 104 
 

AZT and AZT/"-Interferon A/D, NTP TR 469 59 

TABLE 16 

Mean Body Weights and Survival of Female Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

Weeks Vehicle Control 5,000 U "-IFN A 500 U "-IFN A/D 5,000 U "-IFN A/D 

on Av. Wt. No. of Av. Wt. Wt. (% of No. of Av. Wt. Wt. (% of No. of Av. Wt. Wt. (% of No. of 

Study (g) Survivors (g) controls) Survivors (g) controls) Survivors (g) controls) Survivors 

1 19.6 50 19.5 100 50 19.3 99 50 19.0 97 50 

2 21.4 50 21.2 99 50 21.4 100 50 21.3 100 49 

3 23.2 50 22.3 96 50 22.6 97 50 22.7 98 49 

4 23.7 50 23.3 98 50 23.9 101 50 23.8 100 48 

5 25.0 50 24.7 99 50 24.8 99 50 24.6 98 48 

6 26.4 50 25.9 98 50 26.1 99 50 25.9 98 48 

7 27.6 50 27.3 99 50 27.4 99 50 27.3 99 48 

8 27.2 50 27.5 101 50 27.5 101 50 27.4 101 48 

9 27.3 50 27.7 102 50 27.4 100 50 27.1 99 48 

10 28.4 50 28.1 99 50 28.0 99 50 27.8 98 48 

11 29.1 50 29.2 100 50 29.1 100 50 29.1 100 48 

13 30.8 50 30.9 100 50 31.1 101 50 30.8 100 48 

17 33.9 50 34.5 102 50 33.6 99 50 33.9 100 48 

21 37.9 50 38.6 102 50 38.1 101 50 38.5 102 48 

25 41.2 50 41.2 100 49 40.7 99 50 41.2 100 48 

29 43.6 50 43.6 100 49 43.1 99 50 43.5 100 48 

33 46.0 50 46.3 101 49 45.9 100 50 45.9 100 48 

37 48.5 50 48.1 99 49 47.4 98 50 47.5 98 48 

41 50.4 50 49.7 99 49 49.9 99 50 49.5 98 48 

45 52.4 50 52.1 99 49 52.0 99 50 51.5 98 47 

49 53.6 50 53.4 100 49 52.9 99 50 52.9 99 47 

53 55.7 49 55.1 99 49 54.5 98 50 54.5 98 47 

57 56.0 49 54.2 97 49 54.8 98 50 55.1 98 47 

61 58.4 48 57.1 98 49 56.9 97 50 56.5 97 47 

65 58.6 48 57.3 98 48 57.3 98 50 56.3 96 47 

69 61.0 48 60.6 99 47 60.0 98 50 60.0 98 47 

73 62.1 48 61.4 99 46 61.7 99 49 60.8 98 47 

77 63.1 47 61.2 97 46 62.4 99 49 61.8 98 46 

81 62.4 47 61.0 98 46 61.2 98 48 60.8 97 46 

85 61.4 46 59.6 97 42 60.4 98 47 61.1 100 42 

89 59.7 44 59.7 100 39 59.6 100 46 60.1 101 41 

93 58.8 43 61.8 105 37 60.5 103 44 59.4 101 39 

97 57.0 35 60.2 106 37 58.6 103 42 57.5 101 31 

101 55.1 29 57.9 105 36 57.6 105 36 55.0 100 27 

Mean for weeks 

1-13 25.8 25.6 99 25.7 100 25.6 99 

14-52 45.3 45.3 100 44.8 99 44.9 99 

53-101 59.2 59.0 100 58.9 99 58.4 99 
 

60 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

Pathology and Statistical Analysis 

This section describes the statistically significant or 

biologically noteworthy changes in the incidences of 

neoplasms and/or nonneoplastic lesions of the lung 

and liver. Summaries of the incidences of neoplasms 

and nonneoplastic lesions, statistical analyses of primary neoplasms that occurred with an incidence of at 

least 5% in at least one animal group, and historical 

incidences for the neoplasms mentioned in this section 

are presented in Appendix C for male mice and 

Appendix D for female mice. 

TABLE 17 

Lung: The incidences of alveolar/bronchiolar adenoma or carcinoma (combined) in females receiving 

5,000 U "-interferon A or 500 U "-interferon A/D 

were greater than that in the vehicle control group 

(Tables 17 and D2). These marginal increases were 

not considered associated with "-interferon exposure 

since the incidences in these groups were within the 

range of historical controls (Tables 17 and D3), there 

was no dose response in groups receiving "-interferon 

A/D, there was no corresponding increase in the 

incidences of alveolar/bronchiolar hyperplasia, and 

there was no increase in the incidence of lung 

neoplasms in male mice. 

Incidences of Neoplasms of the Lung in Female Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Alveolar/bronchiolar Adenomaa 

Overall rateb 0/50 (0%) 3/50 (6%) 5/50 (10%) 4/50 (8%) c Adjusted rate 0.0% 7.8% 14.4% 14.0% 

Terminal rated 0/25 (0%)) 1/31 (3%) 3/32 (9%) 3/25 (12%) 

First incidence (days) —f 601 698 581 e Logistic regression test P=0.234 P=0.127 P=0.047 P=0.057 

Alveolar/bronchiolar Carcinomag 

Overall rate 2/50 (4%) 7/50 (14%) 4/50 (8%) 0/50 (0%) 

Adjusted rate 7.3% 19.2% 10.3% 0.0% 

Terminal rate 1/25 (4%) 3/31 (10%) 2/32 (6%) 0/25 (0%) 

First incidence (days) 708 612 483 — 

Logistic regression test P=0.100N P=0.078 P=0.302 P=0.253N 

Alveolar/bronchiolar Adenoma or Carcinomah 

Overall rate 2/50 (4%) 9/50 (18%) 9/50 (18%) 4/50 (8%) 

Adjusted rate 7.3% 23.9% 23.8% 14.0% 

Terminal rate 1/25 (4%) 4/31 (13%) 5/32 (16%) 3/25 (12%) 

First incidence (days) 708 601 483 581 

Logistic regression test P=0.505N P=0.026 P=0.028 P=0.311 

a Historical incidence for 2-year NTP feed studies with untreated control groups (mean ± standard deviation): 85/1,472 (5.8% ± 4.8%); 

range, 0%-24% b	 Number of neoplasm-bearing animals/number of animals microscopically examined 

Kaplan-Meier estimated neoplasm incidence at the end of the study after adjustment for intercurrent mortality d Observed incidence at terminal kill e Beneath the vehicle control incidence are the P values associated with the trend test (the "-interferon A group was excluded from the trend 

test). Beneath the dosed group incidence are the P values corresponding to pairwise comparisons between the vehicle controls and that dosed 

group. The logistic regression test regards neoplasms in animals dying prior to terminal kill as nonfatal. A negative trend or a lower 

incidence in a dosed group is indicated by N. f	 Not applicable; no neoplasms in animal group g	 Historical incidence: 31/1,472 (2.1% ± 2.3%); range, 0%-8% h	 Historical incidence: 114/1,472 (7.7% ± 5.1%); range, 2%-26% 
 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 61 

Liver: Relatively high incidences of chronic inflammation (vehicle control, 15/50; 5,000 U "-IFN A, 

20/50; 500 U "-IFN A/D, 17/50; 5,000 U "-IFN 

A/D, 18/50; Table C3) and hepatocyte karyomegaly 

(12/50, 12/50, 14/50, 8/50) occurred in all groups of 

male mice; these lesions were usually observed 

together in the same liver. Similar lesions were observed in very few females, and the severity was also 

less than that observed in many males (Table D4). 

Liver sections from four of five male mice with liver 

lesions were positive for bacterial organisms consistent with Helicobacter when examined using Steiner’s 

modification of the Warthin-Starry silver stain 

(Appendix R). 
 

62 AZT and AZT/"-Interferon A/D, NTP TR 469 

2-YEAR AZT/ 

500 U "-INTERFERON A/D STUDY 

Survival 

Estimates of 2-year survival probabilities for male and 

female mice are shown in Table 18 and in the KaplanMeier survival curves (Figure 5). Survival of all 

dosed groups of mice was similar to that of the vehicle 

control groups. 

Body Weights and Clinical Findings 

The mean body weights of dosed mice were generally 

similar to those of the vehicle control groups 

TABLE 18 

throughout the study (Tables 19 and 20; Figure 6). 

There were no chemical-related clinical findings. 

Hematology and Bone Marrow Analyses 

The hematology and bone marrow data for mice in the 

2-year study of AZT/500 U "-interferon A/D are 

listed in Table K4. In general, a dose- and timedependent, minimal to mild, macrocytic, nonresponsive anemia, similar to that observed in the 

2-year AZT study, occurred in all dosed groups of 

male and female mice. The data suggest that the addition of 500 U of "-interferon A/D did not affect the 

hematotoxicity related to treatment with AZT. 

Survival of Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Male 

Animals initially in study	 50 50 50 50 

Accidental deathsa 0 2 3 0 

Moribund 13 14 5 9 

Natural deaths 1 7 4 6 

Animals surviving to study termination 36 27 38 35 

Percent probability of survival at end of studyb 72 56 81 70 c Mean survival (days)	 694 637 680 702 

Survival analysisd	 P=0.816 P=0.136 P=0.393N P=0.998 

Female 

Animals initially in study	 50 50 50 50 

Accidental deathsa	 3 4 2 4 a Missing 0 0 0 1 

Moribund 7 8 11 12 

Natural deaths 7 6 5 9 

Animals surviving to study termination 33 32 32 24 

Percent probability of survival at end of study 70 70 67 54 

Mean survival (days) 662 639 663 627 

Survival analysis	 P=0.402 P=0.906 P=0.752 P=0.138 

a Censored from survival analyses b	 Kaplan-Meier determinations 

Mean of all deaths (uncensored, censored, and terminal sacrifice) d	 The result of the life table trend test (Tarone, 1975) is in the vehicle control column, and the results of the life table pairwise comparisons 

(Cox, 1972) with the vehicle controls are in the dosed group columns. Lower mortality in a dosed group is indicated by N. 

c 
 

AZT and AZT/"-Interferon A/D, NTP TR 469 63 

FIGURE 5
 

Kaplan-Meier Survival Curves for Male and Female Mice Administered AZT in Methylcellulose 

by Gavage and 500 U "-Interferon A/D by Subcutaneous Injection for 2 Years
 
 

64 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE 19 

Mean Body Weights and Survival of Male Mice in the 2-Year Gavage Study 

of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Weeks Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

on Av. Wt. No. of Av. Wt. Wt. (% of No. of Av. Wt. Wt. (% of No. of Av. Wt. Wt. (% of No. of 

Study (g) Survivors (g) controls) Survivors (g) controls) Survivors (g) controls) Survivors 

1 24.8 50 24.9 100 50 25.0 101 50 25.1 101 50 

2 26.0 50 26.1 100 49 26.3 101 50 26.3 101 50 

3 27.3 50 27.4 100 48 27.7 102 48 27.3 100 50 

4 27.7 50 27.9 101 48 28.0 101 48 27.6 100 50 

5 28.4 50 28.9 102 48 29.1 103 48 28.5 100 50 

6 29.5 50 29.7 101 48 29.9 101 48 29.6 100 50 

7 30.2 50 30.2 100 48 30.6 101 48 30.0 99 50 

8 31.2 50 31.3 100 48 31.5 101 48 30.6 98 50 

9 32.1 50 32.5 101 48 32.7 102 48 31.8 99 50 

10 32.8 50 33.3 102 48 33.3 102 48 32.4 99 50 

11 32.9 50 33.4 102 48 33.6 102 48 32.5 99 50 

12 34.2 50 34.6 101 48 34.9 102 48 33.9 99 50 

13 34.9 50 35.6 102 48 35.8 103 48 34.8 100 50 

17 36.5 50 37.5 103 48 37.8 104 48 35.7 98 50 

21 39.2 50 39.8 102 47 40.1 102 48 38.2 97 50 

25 40.7 50 41.7 103 47 42.0 103 48 39.9 98 50 

29 43.7 50 44.6 102 47 44.9 103 48 43.1 99 50 

33 45.4 50 46.0 101 47 47.0 104 48 45.4 100 50 

37 45.6 50 46.4 102 47 47.0 103 48 46.0 101 50 

41 46.8 50 47.1 101 47 47.8 102 48 47.1 101 50 

45 46.2 50 46.9 102 46 47.3 102 47 46.9 102 50 

49 46.5 50 47.0 101 46 47.5 102 47 46.9 101 50 

53 46.8 49 47.3 101 46 47.9 102 47 47.3 101 50 

57 46.9 48 47.1 100 45 47.8 102 47 47.2 101 50 

61 47.2 48 47.5 101 45 48.7 103 47 47.8 101 50 

65 47.7 48 47.2 99 45 48.7 102 47 48.2 101 50 

69 47.7 47 46.5 98 45 48.9 103 47 48.2 101 50 

73 47.0 47 45.9 98 44 48.5 103 47 47.3 101 50 

77 46.7 46 45.2 97 43 47.9 103 47 47.0 101 48 

81 46.0 45 44.7 97 40 47.2 103 47 46.2 100 46 

85 44.8 45 43.7 98 38 46.1 103 46 44.9 100 45 

89 44.1 43 43.5 99 37 46.2 105 45 44.2 100 45 

93 44.1 43 42.9 97 36 46.8 106 42 44.0 100 43 

97 42.8 42 41.8 98 32 44.8 105 42 42.2 99 41 

101 41.9 40 41.0 98 32 44.0 105 40 41.7 100 37 

Mean for weeks 

1-13 30.2 30.4 101 30.6 101 30.0 99 

14-52 43.4 44.1 102 44.6 103 43.2 100 

53-101 45.7 44.9 98 47.2 103 45.9 100 
 

AZT and AZT/"-Interferon A/D, NTP TR 469 65 

TABLE 20 

Mean Body Weights and Survival of Female Mice in the 2-Year Gavage Study 

of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Weeks Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

on Av. Wt. No. of Av. Wt. Wt. (% of No. of Av. Wt. Wt. (% of No. of Av. Wt. Wt. (% of No. of 

Study (g) Survivors (g) controls) Survivors (g) controls) Survivors (g) controls) Survivors 

1 19.7 49 19.9 101 49 19.9 101 50 20.0 102 50 

2 21.3 49 21.6 101 49 21.4 101 50 21.4 101 50 

3 22.3 48 22.7 102 49 22.6 101 49 22.7 102 49 

4 22.9 48 23.4 102 48 23.0 100 48 23.3 102 47 

5 23.6 47 24.0 102 48 23.7 100 48 23.7 100 46 

6 25.0 47 25.4 102 48 25.2 101 48 25.1 100 46 

7 25.3 47 25.5 101 48 25.5 101 48 25.6 101 46 

8 25.5 47 25.8 101 48 25.7 101 48 25.8 101 46 

9 26.4 47 27.0 102 47 27.1 103 48 26.7 101 46 

10 26.5 47 27.2 103 47 27.0 102 48 26.9 102 46 

11 27.4 47 27.8 102 47 27.7 101 48 27.5 100 46 

12 28.6 47 29.4 103 47 28.9 101 48 29.1 102 46 

13 29.0 47 29.8 103 47 29.4 101 48 29.5 102 46 

17 31.2 47 32.4 104 47 31.4 101 48 31.9 102 46 

21 32.9 47 33.2 101 47 33.4 102 48 33.5 102 46 

25 34.6 47 36.0 104 47 35.7 103 48 35.4 102 46 

29 37.2 47 38.7 104 47 37.9 102 48 38.2 103 46 

33 39.1 47 40.3 103 47 40.1 103 48 40.3 103 46 

37 41.0 47 42.1 103 47 41.4 101 48 42.2 103 46 

41 42.8 47 44.2 103 47 43.5 102 48 43.7 102 46 

45 43.1 47 44.6 104 47 43.8 102 48 43.6 101 46 

49 44.5 47 46.1 104 47 45.1 101 48 44.9 101 46 

53 45.4 47 47.0 104 47 46.1 102 48 45.8 101 46 

57 46.4 47 47.9 103 47 47.0 101 48 47.4 102 45 

61 47.9 47 49.4 103 47 48.5 101 48 48.6 102 45 

65 50.5 47 51.4 102 46 51.1 101 46 50.9 101 44 

69 50.9 46 51.9 102 45 51.3 101 46 51.4 101 44 

73 50.5 46 52.2 103 44 51.5 102 46 51.3 102 43 

77 50.2 45 52.1 104 41 50.7 101 45 50.0 100 43 

81 50.1 45 52.4 105 39 50.2 100 45 49.5 99 43 

85 49.4 44 51.8 105 39 49.4 100 45 49.2 100 41 

89 49.8 42 51.3 103 37 50.0 100 40 49.7 100 36 

93 51.1 42 53.6 105 34 51.0 100 38 50.3 98 34 

97 49.0 40 51.8 106 33 49.0 100 36 47.8 98 31 

101 49.0 38 51.0 104 32 48.7 99 34 46.6 95 29 

Mean for weeks 

1-13 24.9 25.3 102 25.2 101 25.2 101 

14-52 38.5 39.7 103 39.1 102 39.3 102 

53-101 49.2 51.1 104 49.6 101 49.1 100 
 

66 AZT and AZT/"-Interferon A/D, NTP TR 469 

FIGURE 6
 

Growth Curves for Male and Female Mice Administered AZT in Methylcellulose 

by Gavage and 500 U "-Interferon A/D by Subcutaneous Injection for 2 Years
 
 

 

 

67 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

Pathology and Statistical Analyses 

This section describes the statistically significant or 

biologically noteworthy changes in the incidences of 

neoplasms and nonneoplastic lesions of the vagina, 

liver, and kidney. Summaries of the incidences of 

neoplasms and nonneoplastic lesions and statistical 

analyses of primary neoplasms that occurred with an 

incidence of at least 5% in at least one animal group 

are presented in Appendix E for male mice and 

Appendix F for female mice. 

TABLE 21 

Vagina: The incidences of squamous cell carcinoma 

of the vagina in females receiving 60 or 120 mg 

AZT/kg and 500 U "-interferon A/D were significantly greater than in the vehicle controls, and the 

incidences of this neoplasm occurred with a positive 

trend (Tables 21 and F2). The incidences of epithelial 

hyperplasia of the vagina in females receiving 60 or 

120 mg AZT/kg with 500 U "-interferon A/D were 

significantly greater than in the vehicle controls 

(Tables 21 and F3). These lesions were described for 

the 2-year AZT study. 

Incidences of Neoplasms and Nonneoplastic Lesions of the Vagina in Female Mice 

in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Number Examined Microscopically 

Epithelium, Hyperplasiaa 49 0

44 

4 (1.5)b 

48 

6* (2.0) 

48 

11** (1.2) 

Epithelium, Hyperplasia, Atypical 0 0 2 (3.0) 1 (4.0) 

Squamous Cell Carcinoma 

Overall ratec 

Adjusted rated 0/49 (0%) 

0.0% 

0/44 (0%) 

0.0% 

5/48 (10%) 

15.6% 

6/48 (12%) 

21.1% 

Terminal ratee 0/33 (0%) 0/32 (0%) 5/32 (16%) 3/24 (13%) 

First incidence (days) 

Logistic regression testf —g 

P<0.001 

— 

— 

729 (T) 

P=0.030 

631 

P=0.011 

(T)Terminal sacrifice 

* Significantly different (P#0.05) from the vehicle control group by the logistic regression test 

** P#0.01 a Number of animals with lesion 

b Average severity of lesions in affected animals: 1=minimal, 2=mild, 3=moderate, 4=marked 

Number of animals with neoplasm per number of animals necropsied d Kaplan-Meier estimated neoplasm incidence at the end of the study after adjustment for intercurrent mortality e Observed incidence at terminal kill 

f In the vehicle control column are the P values associated with the trend test. In the dosed group columns are the P values corresponding to 

the pairwise comparisons between the vehicle controls and that dosed group. The logistic regression test regards lesions in animals dying 

prior to terminal kill as nonfatal. 

g Not applicable; no neoplasms in animal group 

Liver: The incidences of hepatocellular adenoma or male vehicle control groups from the three companion 

carcinoma (combined) and of hepatocellular adenoma, studies (AZT, 36/50; "-interferon A/D, 30/50; 

hepatocellular carcinoma, or hepatoblastoma (com- AZT/5,000 U "-interferon A/D, 36/50) suggest that 

bined) were marginally increased in males receiving the incidence in the concurrent vehicle control group 

30 or 60 mg AZT/kg and 500 U "-interferon A/D is somewhat low, rather than the incidences in the 30 

(Tables 22 and E2). However, the incidences of liver and 60 mg/kg AZT and 500 U "-interferon A/D 

neoplasms in males that received 120 mg/kg AZT and groups being high. Also, incidences of potentially 

500 U "-interferon A/D were not significantly in- preneoplastic foci of alteration in males administered 

creased. While the concurrent vehicle control group 30 or 60 mg/kg AZT and 500 U "-interferon A/D 

provides the most appropriate group for comparison, were not different from the vehicle controls 

the incidences of combined liver neoplasms in the (Table E3). Accordingly, the marginal increases in 
 

68 AZT and AZT/"-Interferon A/D, NTP TR 469 

hepatocellular neoplasms in these two groups were not and observed throughout the liver (usually not within 

considered related to administration of AZT and the proliferative lesions), but appeared most pro500 U "-interferon A/D. nounced in the portal regions. Similar lesions were 

observed in very few females, and the severity was 

also less than that observed in many males (Tables 22 

Relatively high incidences of chronic inflammation and F3). Liver sections from three of five male mice 

and hepatocyte karyomegaly occurred in all groups of with liver lesions were positive for bacterial organmale mice; these lesions were usually observed isms consistent with Helicobacter when examined 

together in the same liver (Tables 22 and E3). These using Steiner’s modification of the Warthin-Starry 

changes were generally mild to moderate in severity silver stain (Appendix R). 

TABLE 22 

Incidences of Neoplasms and Nonneoplastic Lesions of the Liver in Mice in the 2-Year Gavage Study 

of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Male 

Number Examined Microscopically 50 50 50 50 

Chronic Inflammationa 39 (2.7)b 38 (2.8) 38 (2.7) 44 (2.7) 

Hepatocyte, Karyomegaly 33 (3.0) 31 (2.7) 35 (3.0) 40 (2.9) 

Necrosis, Focal 1 (1.0) 7* (2.6) 0 4 (3.0) 

Hemangiosarcoma 3 5 4 4 

Hepatocellular Adenoma 16 16 19 18 

Hepatocellular Carcinoma 13 20 17 14 

Hepatocellular Adenoma or Carcinoma 24 31* 33* 29 

Hepatoblastoma 1 1 1 0 

Hepatocellular Carcinoma 

or Hepatoblastoma 13 21 17 14 

Hepatocellular Adenoma, 

Hepatocellular Carcinoma, 

or Hepatoblastoma 24 32* 33* 29 

Female 

Number Examined Microscopically 50 50 50 49 

Chronic Inflammation 6 (1.5) 6 (1.3) 5 (1.4) 7 (1.7) 

Hepatocyte, Karyomegaly 0 1 (3.0) 1 (2.0) 0 

Necrosis, Focal 4 (2.0) 0 6 (1.5) 8 (2.3) 

Hepatocellular Adenoma 11 17 14 14 

Hepatocellular Carcinoma 13 4 5 10 

Hepatocellular Adenoma or Carcinoma 20 20 18 22 

* Significantly different (P#0.05) from the vehicle control group by the logistic regression test a Number of animals with lesion 

b Average severity of lesions in affected animals: 1=minimal, 2=mild, 3=moderate, 4=marked 

Kidney: A renal tubule adenoma was observed in 500 U "-interferon A/D (0/50,0/501/50,0/50; 

one male mouse administered 60 mg AZT/kg and Table E1). 
 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 69 

2-YEAR AZT/ 

5,000 U "-INTERFERON A/D STUDY 

Survival 

Estimates of 2-year survival probabilities for male and 

female mice are shown in Table 23 and in the KaplanMeier survival curves (Figure 7). Survival of all 

dosed groups of mice was similar to that of the vehicle 

control groups. 

Body Weights and Clinical Findings 

The mean body weights of dosed and vehicle 

control mice were similar throughout the study 

(Figure 8; Tables 24 and 25). With the exception 

of head masses observed in all dosed groups of 

TABLE 23 

males, there were no chemical-related clinical 

findings. 

Hematology and Bone Marrow Analyses 

The hematology and bone marrow data for mice in the 

2-year study of AZT/5,000 U "-interferon A/D are 

listed in Table K5. In general, a dose- and timedependent, minimal to mild, macrocytic, nonresponsive anemia, similar to that observed in the 

2-year AZT study, occurred in all dosed groups of 

male and female mice. The data suggest that the addition of 5,000 U of "-interferon A/D did not affect the 

hematotoxicity related to treatment with AZT. 

Survival of Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Male 

Animals initially in study 50 50 50 50 

Accidental deathsa 0 1 1 0 

Moribund 9 11 9 6 

Natural deaths 10 3 5 10 

Animals surviving to study termination 

Percent probability of survival at end of studyb 

31 

62 

35 

71 

35 

72 

34 

68 

Mean survival (days)c 694 683 668 684 

Survival analysisd P=0.836N P=0.505N P=0.547N P=0.782N 

Female 

Animals initially in study 50 50 50 50 

Accidental deathsa 0 0 2 1 

Moribund 8 7 6 8 

Natural deaths 5 5 6 9 

Animals surviving to study termination 37 38e 36 32 

Percent probability of survival at end of study 74 76 75 65 

Mean survival (days) 703 707 669 685 

Survival analysis P=0.339 P=0.959N P=1.000N P=0.496 

a Censored from survival analyses b	 Kaplan-Meier determinations 

Mean of all deaths (uncensored, censored, and terminal sacrifice) d	 The result of the life table trend test (Tarone, 1975) is in the vehicle control column, and the results of the life table pairwise comparisons 

(Cox, 1972) with the vehicle controls are in the dosed group columns. A negative trend or lower mortality in a dosed group is indicated 

by N. e Includes one animal that died during the last week of the study 

c 
 

70 AZT and AZT/"-Interferon A/D, NTP TR 469 

FIGURE 7
 

Kaplan-Meier Survival Curves for Male and Female Mice Administered AZT in Methylcellulose 

by Gavage and 5,000 U "-Interferon A/D by Subcutaneous Injection for 2 Years
 
 

AZT and AZT/"-Interferon A/D, NTP TR 469 71 

FIGURE 8
 

Growth Curves for Male and Female Mice Administered AZT in Methylcellulose 

by Gavage and 5,000 U "-Interferon A/D by Subcutaneous Injection for 2 Years
 
 

72 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE 24 

Mean Body Weights and Survival of Male Mice in the 2-Year Gavage Study 

of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Weeks Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

on Av. Wt. No. of Av. Wt. Wt. (% of No. of Av. Wt. Wt. (% of No. of Av. Wt. Wt. (% of No. of 

Study (g) Survivors (g) controls) Survivors (g) controls) Survivors (g) controls) Survivors 

1 24.9 50 25.0 100 50 25.4 102 50 25.1 101 50 

2 26.5 50 26.6 100 50 26.9 102 50 26.5 100 50 

3 27.2 50 27.3 100 50 27.7 102 50 27.2 100 50 

4 27.9 50 28.1 101 50 28.5 102 50 28.1 101 50 

5 28.6 50 28.6 100 50 29.2 102 50 28.7 100 50 

6 29.9 50 30.0 100 50 30.5 102 50 30.0 100 50 

7 30.4 50 30.6 101 50 31.0 102 50 30.4 100 50 

8 31.1 50 31.6 102 50 32.0 103 50 31.3 101 50 

9 32.0 50 32.4 101 50 33.0 103 50 32.1 100 50 

10 33.3 50 33.8 102 50 34.1 102 50 33.3 100 50 

11 33.8 50 34.6 102 50 34.8 103 50 34.0 101 50 

12 34.3 50 35.2 103 50 35.6 104 50 34.7 101 50 

13 35.2 50 36.0 102 50 36.6 104 50 35.5 101 50 

17 37.9 50 39.4 104 50 39.6 105 50 38.1 101 50 

21 41.0 50 42.8 104 50 42.9 105 50 41.3 101 50 

25 42.8 50 44.4 104 50 44.6 104 49 43.2 101 50 

29 43.3 50 45.6 105 50 45.4 105 49 44.2 102 50 

33 45.2 50 47.1 104 50 47.1 104 48 45.8 101 50 

37 45.7 50 47.4 104 50 47.4 104 48 46.2 101 50 

41 46.0 50 47.5 103 50 47.5 103 48 46.6 101 50 

45 46.9 50 47.6 102 50 47.8 102 48 46.9 100 50 

49 47.8 50 48.2 101 50 48.1 101 48 47.7 100 50 

53 47.4 50 48.4 102 48 47.7 101 47 47.6 100 50 

57 47.7 49 48.4 102 48 47.6 100 46 47.7 100 50 

61 48.1 49 48.5 101 48 47.8 99 46 48.0 100 49 

65 47.7 49 47.8 100 47 47.4 99 46 47.6 100 49 

69 47.3 47 47.2 100 46 46.6 99 46 47.0 99 48 

73 46.9 47 47.1 100 46 46.5 99 44 46.5 99 47 

77 46.4 47 46.8 101 45 46.0 99 44 46.1 99 45 

81 45.9 46 47.3 103 42 46.5 101 43 46.3 101 43 

85 45.1 45 46.3 103 42 45.5 101 42 45.0 100 41 

89 44.0 44 45.8 104 42 44.6 101 41 43.9 100 40 

93 43.2 43 44.7 104 42 44.1 102 39 42.9 99 38 

97 41.9 42 43.6 104 41 43.3 103 37 42.4 101 38 

101 41.0 36 42.9 105 37 42.8 104 37 41.6 102 37 

Mean for weeks 

1-13 30.4 30.8 101 31.2 103 30.5 100 

14-52 44.1 45.6 103 45.6 103 44.4 101 

53-101 45.6 46.5 102 45.9 101 45.6 100 
 

AZT and AZT/"-Interferon A/D, NTP TR 469 73 

TABLE 25 

Mean Body Weights and Survival of Female Mice in the 2-Year Gavage Study 

of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Weeks Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

on Av. Wt. No. of Av. Wt. Wt. (% of No. of Av. Wt. Wt. (% of No. of Av. Wt. Wt. (% of No. of 

Study (g) Survivors (g) controls) Survivors (g) controls) Survivors (g) controls) Survivors 

1 20.0 50 19.8 99 50 19.8 99 49 20.0 100 50 

2 21.4 50 21.4 100 50 21.4 100 49 21.6 101 50 

3 22.1 50 22.2 101 50 22.5 102 49 22.4 101 50 

4 22.7 50 23.0 101 50 23.3 103 49 23.3 103 50 

5 24.0 50 23.9 100 50 24.0 100 49 24.3 101 49 

6 24.9 50 24.5 98 50 24.7 99 49 24.8 100 49 

7 25.8 50 25.4 98 50 25.7 100 49 25.7 100 49 

8 26.3 50 26.2 100 50 26.2 100 49 26.4 100 49 

9 27.2 50 26.8 99 50 27.0 99 49 27.0 99 49 

10 28.1 50 27.4 98 50 27.7 99 49 28.0 100 49 

11 28.9 50 28.2 98 50 28.8 100 49 28.8 100 49 

12 29.5 50 29.1 99 50 29.4 100 49 29.7 101 49 

13 29.8 50 29.3 98 50 29.7 100 49 29.9 100 49 

17 33.4 50 32.8 98 50 33.3 100 49 33.7 101 49 

21 36.0 50 35.6 99 50 35.3 98 49 36.1 100 49 

25 37.9 50 37.3 98 50 37.0 98 49 38.0 100 49 

29 39.2 50 38.6 99 50 38.1 97 48 38.8 99 49 

33 41.1 50 40.9 100 50 40.0 97 48 40.9 100 49 

37 42.8 50 42.1 98 50 41.4 97 48 42.4 99 49 

41 43.5 50 43.2 99 50 42.4 98 48 43.6 100 49 

45 44.6 50 44.5 100 50 43.1 97 48 44.5 100 49 

49 46.8 50 46.6 100 50 45.1 96 47 46.9 100 49 

53 48.0 50 48.1 100 50 47.0 98 46 48.4 101 49 

57 49.3 50 49.2 100 50 48.0 97 46 49.3 100 49 

61 50.0 50 50.4 101 50 49.0 98 46 50.2 100 49 

65 51.1 50 51.1 100 50 49.6 97 46 50.8 99 49 

69 51.6 50 52.0 101 50 49.9 97 46 51.5 100 49 

73 52.8 49 52.3 99 50 50.7 96 44 52.4 99 48 

77 53.7 49 52.7 98 50 51.4 96 44 53.1 99 48 

81 53.1 49 52.9 100 48 51.5 97 44 53.3 100 47 

85 52.4 46 52.8 101 46 51.2 98 43 53.1 101 46 

89 51.1 44 52.0 102 45 50.8 99 41 52.3 102 44 

93 50.1 43 50.9 102 43 50.0 100 40 52.0 104 41 

97 50.1 40 50.7 101 41 49.6 99 40 52.3 104 37 

101 48.8 38 49.1 101 40 48.0 98 39 50.8 104 34 

Mean for weeks 

1-13 25.4 25.2 99 25.4 100 25.5 100 

14-52 40.6 40.2 99 39.5 97 40.5 100 

53-101 50.9 51.1 100 49.7 98 51.5 101 
 

 

74 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

Pathology and Statistical Analyses 

This section describes the statistically significant or 

biologically noteworthy changes in the incidences of 

neoplasms and/or nonneoplastic lesions of the vagina, 

adrenal cortex, and liver. Summaries of the incidences of neoplasms and nonneoplastic lesions and 

statistical analyses of primary neoplasms that occurred 

with an incidence of at least 5% in at least one animal 

group are presented in Appendix G for male mice and 

Appendix H for female mice. 

TABLE 26 

Vagina: The incidences of squamous cell carcinoma 

of the vagina in females receiving 60 or 120 mg 

AZT/kg and 5,000 U "-interferon A/D were significantly greater than that in the vehicle controls, and the 

incidences occurred with a positive trend (Tables 26 

and H2). The incidences of epithelial hyperplasia of 

the vagina in females receiving 60 or 120 mg AZT/kg 

and 5,000 U "-interferon A/D were significantly 

greater than that in the vehicle controls (Tables 26 and 

H3). These lesions were described for the 2-year 

AZT study. 

Incidences of Neoplasms and Nonneoplastic Lesions of the Vagina in Female Mice 

in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Number Examined Microscopically 50 48 48 50 

Epithelium, Hyperplasiaa 1 (2.0)b 3 (2.0) 7* (2.0) 12* (1.8) 

Epithelium, Hyperplasia, Atypical 0 1 (3.0) 1 (3.0) 3 (2.3) 

Squamous Cell Papilloma c Overall rate 1/50 (2%) 1/48 (2%) 0/48 (0%) 0/50 (0%) 

Squamous Cell Carcinoma 

Overall rate 0/50 (0%) 0/48 (0%) 5/48 (10%) 4/50 (8%) 

Adjusted rated 0.0% 0.0% 13.9% 12.5% e Terminal rate 0/37 (0%) 0/38 (0%) 5/36 (14%) 4/32 (13%) 

First incidence (days) —g — 730 (T) 730 (T) 

Logistic regression testf P=0.009 — P=0.031 P=0.046 

Squamous Cell Papilloma or Squamous Cell Carcinoma 

Overall rate 1/50 (2%) 1/48 (2%) 5/48 (10%) 4/50 (8%) 

Adjusted rate 2.7% 2.6% 13.9% 12.5% 

Terminal rate 1/37 (3%) 1/38 (3%) 5/36 (14%) 4/32 (13%) 

First incidence (days) 733 (T) 733 (T) 730 (T) 730 (T) 

Logistic regression test P=0.047 P=0.747N P=0.093 P=0.136 

(T)Terminal sacrifice 

* Significantly different (P#0.05) from the vehicle control group by the logistic regression test a Number of animals with lesion 

b Average severity of lesions in affected animals: 1=minimal, 2=mild, 3=moderate, 4=marked 

Number of animals with neoplasm per number of animals necropsied d Kaplan-Meier estimated neoplasm incidence at the end of the study after adjustment for intercurrent mortality e Observed incidence in animals at terminal kill 

f In the vehicle control column are the P values associated with the trend test. In the dosed group columns are the P values corresponding to 

the pairwise comparisons between the vehicle controls and that dosed group. The logistic regression test regards lesions in animals dying 

prior to terminal kill as nonfatal. A lower incidence in a dose group is indicated by N. g Not applicable; no neoplasms in animal group 
 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 75 

Adrenal Cortex: The incidences of focal cytoplasmic 

alteration (vehicle control, 3/49; 30 mg/kg, 10/50; 

60 mg/kg, 6/50; 120 mg/kg, 18/50; Table G3) in 

males administered 120 mg AZT/kg and 5,000 U 

"-interferon A/D and of focal hyperplasia (0/49, 2/50, 

7/50, 3/50) in males administered 60 mg AZT/kg and 

5,000 U "-interferon A/D were significantly greater 

than those in the vehicle controls. 

Liver: Relatively high incidences of chronic inflammation (45/50; 43/50; 38/50; 41/50; Table G3) and 

hepatocyte karyomegaly (37/50, 32/50, 31/50, 32/50) 

occurred in all groups of male mice; these lesions 

were usually observed together in the same liver. 

These changes were generally mild to moderate in 

severity and observed throughout the liver (usually not 

within proliferative lesions), but they appeared most 

pronounced in the portal regions. Similar lesions 

were observed in very few females, and the severity 

was also less than that observed in many males 

(Table H3). Liver sections from four of five males 

with liver lesions were positive for bacterial organisms consistent with Helicobacter when examined 

using Steiner’s modification of the Warthin-Starry 

silver stain (Appendix R). 

GENETIC TOXICOLOGY 

AZT is mutagenic. Positive results were obtained 

with AZT (0.003 to 3 μg/plate) in S. typhimurium 

strain TA102 without S9 activation enzymes and 

with 30% hamster liver S9; no mutagenic response 

was detected in strain TA97, TA98, TA100, TA104, 

or TA1535 (0.001 to 6 μg/plate), with or without 

hamster or rat liver S9 (Table I1). In cytogenetic tests 

with cultured Chinese hamster ovary cells, AZT 

induced sister chromatid exchanges (Table I2), but not 

chromosomal aberrations (Table I3), with and without 

S9. The sister chromatid exchange response in the 

absence of S9 was much stronger and occurred at 

much lower doses than the response observed in the 

presence of S9. AZT, administered by gavage three 

times at 24-hour intervals at doses ranging from 200 

to 2,000 mg/kg, induced increased frequencies of 

micronucleated polychromatic erythrocytes in bone 

marrow (Table I4) and peripheral blood (Table I5) 

samples of male mice (Phillips et al., 1991). The 

increased frequencies of micronuclei were very 

impressive, with the three treatment groups in the 

bone marrow analysis showing increases that were 

from three to nine times the level induced by the 

positive control, dimethylbenzanthracene (Table I4). 

The increases noted in peripheral blood (Table I5) 

were of similar or greater magnitude. Results of a 

14-week peripheral blood micronucleus test with male 

mice showed significant increases in the frequencies 

of micronucleated polychromatic and normochromatic 

erythrocytes at doses of 100 and 1,000 mg AZT/kg 

body weight per day (Table I6). No increased 

frequency of micronucleated cells was noted at the 

lowest dose of 25 mg/kg per day. 
 

76 AZT and AZT/"-Interferon A/D, NTP TR 469 
PLATE 1 

Squamous cell carcinoma of the vagina in a female B6C3F1 mouse 

administered 120 mg/kg AZT by gavage for 2 years. Note the marked 

invasion of the submucosa and muscle wall and numerous keratinfilled pockets in the disorganized proliferation of neoplastic epitheliium. H&E; 30× 

PLATE 2 

Squamous cell papilloma of the vagina in a female B6C3F1 mouse 

administered 120 mg/kg AZT by gavage for 2 years. This protuberant 

mass has more regular architecture and is more circumscribed than 

squamous cell carcinima. Note that the continuity of this mass with 

the vaginal wall was lost in sectioning. H&E; 30× 

PLATE 3 PLATE 4 

Hyperplasia of the vaginal epithelium in a female B6C3F1 mouse Atypical hyperplasia of the vaginal epithelium in a female B6C3F1 

administered 120 mg/kg AZT by gavage for 2 years. Note the focal mouse administered 120 mg/kg AZT by gavage for 2 years. The arrow 

thickening of the vaginal mucosal epithelium. Epithelium in the indicates an area where cells have lost their cohesiveness and become 

thickened layers remains relatively uniform and ordered. H&E; 75× dysplastic. H&E; 60× 
 

77 

DISCUSSION AND CONCLUSIONS
 

3N-Azido-3N-deoxythymidine (AZT) was the first dideoxynucleoside approved for the treatment of human 

immunodeficiency virus (HIV) infection and is the 

best characterized and most widely used drug in this 

class. However, prolonged AZT monotherapy invariably leads to the emergence of HIV variants with 

reduced sensitivity and ultimately to the development 

of resistance. Therefore, a number of combination 

therapies involving AZT and other drugs have been 

evaluated. Interferon is an attractive choice for combination therapy with AZT because it inhibits viral 

replication at steps in the viral life cycle different 

from reverse transcription. Ideally, the development 

of resistance to such a combination would be more 

difficult and require a longer period of treatment, or 

perhaps might not occur at all. Reports that recombinant human "-interferon A suppressed the replication of HIV in vitro (Ho et al., 1985; Yamamoto 

et al., 1986; Hartshorn et al., 1987a) and the demonstration that coadministration of AZT and recombinant 

human "-interferon A resulted in synergistic 

suppression of HIV replication in human cell lines 

(Hartshorn et al., 1987b; Krown, 1990) prompted the 

initiation of clinical trials to evaluate this combination 

in humans (Lane, 1989; Lane et al., 1990). Results 

reported to date (reviewed in Poli et al., 1994) indicate potential benefits associated with "-interferon 

therapy in HIV-positive patients who have relatively 

healthy immune systems (CD4+ counts above 3 150/mm ). In general, however, coadministration of 

"-interferon has failed to produce significant improvement over AZT monotherapy. 

The current studies in B6C3F1 mice evaluate the 

carcinogenic potential of AZT administered as a single 

agent or in combination with "-interferon A/D. 

"-Interferon A/D is a recombinant human hybrid 

interferon with antiviral activity that has been well 

characterized in mice both in vivo and in vitro 

(Ortaldo et al., 1983; Brunda and Rosenbaum, 1984). 

The toxic response in mice has also been well characterized (Rosenthal et al., 1990), and it is very similar 

to the responses observed in humans receiving 

"-interferon therapy. "-Interferon A/D was selected 

for use in these studies because of its wellcharacterized activity in mice and the unavailability of 

adequate quantities of pure mouse interferons at the 

time this series of studies was initiated. Human 

"-interferon A exhibits no activity in mice, but a 

group of mice receiving this interferon was included 

in the 2-year study to allow any nonspecific effects 

associated with administration to be distinguished 

from effects resulting from the actual biological 

activity of "-interferon A/D. 

Twice-daily administration of AZT, 5 days per week, 

for 14 weeks to male and female B6C3F1 mice 

resulted in the development of a poorly regenerative 

macrocytic anemia that increased in severity with dose 

and duration of chemical treatment (Thompson et al., 

1991). Signs of anemia were observed in animals that 

received the highest doses of AZT at the day 5 

sampling point, and by day 23, anemia was apparent 

in mice at all dose concentrations. Analysis of bone 

marrow cellularity at the end of this 14-week study 

revealed significant decreases in erythroid precursors 

and somewhat less severe reductions in myeloid and 

lymphoid precursors, but no indications of a regenerative response in the bone marrow. Macrocytic 

anemia also develops in humans administered AZT 

but generally requires several weeks of treatment to 

become evident. The significantly shorter erythrocyte 

half-life in mice (20 to 40 days) compared to humans 

(127 days) is probably responsible for the more rapid 

appearance of anemia in mice. Also, in humans, 

changes in the peripheral blood associated with AZT 

treatment are accompanied by erythroid hyperplasia in 

the bone marrow, which is the expected response to 

impaired hematopoiesis. 

The selection of AZT dose concentrations for the 

2-year mouse study was based primarily on the toxic 

response in the bone marrow. Because animals would 

be dosed twice daily, a major consideration for the 

2-year study was the potential for cumulative toxicity 

that would eventually exceed the regenerative capacity 

of the hematopoietic system. Moreover, the absence 

of bone marrow regenerative hyperplasia and the 

observed decrease in erythroid precursors in the bone 

marrow suggested that most regeneration was 
 

78 AZT and AZT/"-Interferon A/D, NTP TR 469 

associated with extramedullary hematopoiesis in the 

spleen. 

At doses of 200 mg/kg and greater in the 14-week 

study, reduced hematocrit values, reduced erythrocyte 

and reticulocyte counts, and increased mean cell 

volume were apparent early in the study and became 

more pronounced by study termination. Therefore, 

these doses were considered too high for a 2-year 

study. On the other hand, the response to 100 mg/kg 

was quite mild, particularly in males, where hematocrit values and reticulocyte counts were never 

significantly different from those of the controls. 

Therefore, 100 mg/kg was considered too low for the 

high dose. Single-dose pharmacokinetic studies 

(Trang et al., 1993), conducted in association with the 

14-week study reported here, indicated that AZT 

exhibited linear kinetics in B6C3F1 mice after oral 

administration of doses ranging from 15 to 60 mg/kg. 

In addition, the overall oral bioavailability over this 

dose range was 86%. These results, in combination 

with the results from the 14-week study, suggested 

that total daily doses of 30, 60, or 120 mg/kg, administered as twice-daily doses of 15, 30, or 60 mg/kg, 

would be within the desired dose range based on both 

the toxic response and the capacity of the animals to 

absorb and eliminate AZT. 

No formal 14-week studies were conducted with 

"-interferon A or "-interferon A/D. Studies conducted at NIEHS by Rosenthal et al. (1990) examined 

the toxic responses associated with daily intraperitoneal administration of 1,000, 10,000, or 

100,000 U "-interferon A/D to female C57Bl/6 mice 

for 10 days. Anemia, leukopenia, and thrombocytopenia occurred primarily in animals administered 

10,000 or 100,000 U "-interferon A/D, but thrombocytopenia, increased spleen weights, and lower 

thymus weights were also observed in the group 

receiving 1,000 U. Separate studies in B6C3F mice 1 

conducted at NIEHS indicated that daily intraperitoneal administration of 50,000 or 500,000 U 

"-interferon A/D for 28 days caused anemia, 

thrombocytopenia, and thymic atrophy. Doses of 500 

or 5,000 U had no detectable adverse effect. Daily 

administration of 500,000 U "-interferon A also 

produced no response. 

Ruprecht et al. (1990) examined the antiviral activity 

of "-interferon A/D in vivo in female BALB/c mice 

and found that daily doses of 2,000 to 10,000 U 

"-interferon A/D administered intraperitoneally for 

20 days blocked the replication of Rauscher murine 

leukemia virus and prevented the development of 

associated splenomegaly. These investigators also 

demonstrated that the combination of AZT and 

"-interferon A/D was synergistic in preventing viral 

replication in BALB/c mice. Therefore, based on the 

work of Rosenthal et al. (1990) and Ruprecht et al. 

(1990) and additional studies conducted at NIEHS, 

doses of 500 or 5,000 U "-interferon A/D and 

5,000 U "-interferon A were selected for the 2-year 

combination study with AZT. 

In the studies reported here, administration of AZT 

and "-interferon A/D or A, individually or in combination, for 105 weeks had no effect on the survival or 

mean body weights of male or female B6C3F mice. 1 

Mild anemia characterized by reduced erythrocyte 

counts and increased mean cell volume was apparent 

throughout the study in all groups receiving AZT or 

AZT with "-interferon A/D, and in general, the 

severity of anemia increased with increasing doses of 

AZT. Changes in the peripheral blood were not 

accompanied by a corresponding response in the bone 

marrow, suggesting that regenerative hematopoiesis in 

these groups occurred primarily in the spleen, as 

observed in the 14-week study. Moreover, there was 

no difference in the response of groups administered 

AZT in combination with "-interferon A/D compared 

to those receiving only AZT. The peripheral blood 

and bone marrow of groups receiving only interferons 

did not exhibit any treatment-related responses. 

Higher doses of AZT undoubtedly would have caused 

more severe and potentially life-threatening anemia, 

because in the 14-week study, anemia was progressive 

at doses of 200 mg/kg and greater; therefore, 

120 mg/kg was an adequately high dose. Doses 

administered to humans receiving long-term AZT 

therapy also usually result in a mild chronic anemia 

that is considered dose limiting. 

The most significant neoplastic response associated 

with AZT administration occurred in female mice. In 

groups of female mice given 60 or 120 mg/kg AZT 
 

AZT and AZT/"-Interferon A/D, NTP TR 469 79 

alone or AZT in combination with "-interferon A/D, 

the incidences of squamous cell carcinoma and 

squamous cell carcinoma or papilloma (combined) of 

the vagina were significantly increased. The incidence of hyperplasia of the vaginal epithelium was 

also increased in groups of female mice administered 

60 or 120 mg/kg AZT. 

These results are similar to those observed by Ayers 

et al. (1996) in CD rats and CD-1 mice. In CD rats 

administered 80, 220, or 300 mg AZT/kg body 

weight per day, squamous cell carcinomas of the 

vagina occurred in two females receiving 300 mg/kg; 

however, no hyperplasia of the vaginal epithelium 

occurred in any group of female rats. CD-1 mice 

received AZT by gavage at doses of 30, 60, or 

120 mg/kg per day for 91 days, and then 20, 30, or 

40 mg/kg per day for the remainder of the 22-month 

study. The only neoplasms associated with 

administration of AZT were squamous cell carcinomas 

of the vagina in five females receiving 40 mg/kg, 

squamous cell papillomas of the vagina in one female 

receiving 30 mg/kg and one female receiving 

40 mg/kg, and a squamous polyp in one female 

receiving 40 mg/kg. Although the incidence of 

hyperplasia of the vaginal epithelium was not 

increased above that in the controls, the severity of 

hyperplasia increased with increasing dose 

concentrations of AZT. 

Ayers et al. (1996) administered AZT intravaginally 

to CD-1 mice for 22 months and observed a higher 

incidence of vaginal neoplasms than occurred in the 

above referenced gavage study. They also demonstrated that in female mice there is retrograde flow of 

urine from the discharge point at the base of the vulva 

into the region of the vagina where the neoplasms 

occur. Moreover, in mice, at least 90% of AZT is 

eliminated in urine as the parent compound following 

oral administration. Because there is a high rate of 

cell turnover in the vaginal epithelium as a consequence of the short estrous cycle of mice (4 to 

5 days), Ayers et al. (1996) concluded that prolonged 

exposure of the vaginal epithelium to the relatively 

high concentrations of AZT in urine could explain the 

observed neoplasm response. 

In the present studies, the incidence of hyperplasia of 

the vaginal epithelium exhibited a clear dose response 

that was similar among groups receiving the same 

concentration of AZT but was independent of the coadministration of "-interferon A/D (Table 27). The 

incidences of squamous cell papilloma or carcinoma 

(combined) in groups that received AZT alone also 

increased in a dose-proportional manner. However, 

among groups that received 120 mg/kg AZT, the incidence of vaginal tumors was highest in the group 

administered AZT alone and decreased with 

increasing doses of coadministered "-interferon A/D. 

This decreasing trend in tumor incidence is suggestive 

(P=0.064) of a protective or antineoplastic effect of 

interferon on the carcinogenic response to the highest 

dose of AZT. However, the increase in the incidence 

of AZT-associated hyperplasia was not affected by 

coadministration of "-interferon A/D, and the tumor 

incidence in groups that received 60 mg/kg AZT was 

also unaffected by coadministration of "-interferon 

A/D. This suggests that if interferon was 

antineoplastic, it was only in the groups that received 

120 mg/kg AZT, which seems unlikely. It also seems 

unlikely that the small quantities of interferon that 

escape reabsorption in the kidney and are eliminated 

in the urine of dosed animals could have exerted any 

nonspecific effect on the vaginal epithelium. 

Renal tubule adenomas occurred in three male mice 

and a renal tubule carcinoma occurred in one male 

mouse receiving 120 mg/kg AZT alone (Table 28). 

A renal tubule adenoma was also found in one male 

mouse receiving 60 mg/kg AZT with 500 U 

"-interferon A/D. Although no corresponding 

increase in the incidence of renal tubule hyperplasia 

was observed in routine kidney sections, examination 

of step sections revealed the presence of additional 

hyperplasias. Renal tubule neoplasms occur very 

infrequently in untreated male B6C3F1 mice, and 

because mice eliminate AZT essentially unmetabolized 

in urine, the slight increase in incidences of 

hyperplasia among groups receiving AZT alone and 

the presence of neoplasms in the 120 mg/kg group is 

suggestive of an association with AZT treatment. 

However, the presence of a renal tubule adenoma in 

a male mouse receiving 60 mg/kg AZT with 500 U 

"-interferon A/D, the absence of kidney neoplasms in 

the groups receiving 120 mg/kg AZT with 500 or 

5,000 U "-interferon A/D, and the absence of an 

increase in incidences of renal tubule hyperplasia in 

groups receiving AZT with 500 U "-interferon A/D 

are not consistent with a treatment-related response. 

Moreover, as many as two renal tubule neoplasms 
 

80 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE 27 

Overall Incidences of Vaginal Neoplasms and Hyperplasia of the Vaginal Epithelium in Female Mice 

in the 2-Year Gavage Studies of AZT and AZT/"-Interferon A/Da 

Vehicle Control 30 mg /kg AZT 60 mg/kg AZT 120 mg/kg AZT 

AZT alone 2/197 (1%)b 

1/197 

0/49 (0%) 

3/49 

5/45 (11%) 

4/45 

11/49 (22%) 

11/49 

500 U "-Interferon A/D 0/49 (0%) 

1/49 

0/44 (0%) 

4/44 

5/48 (10%) 

8/48 

6/48 (13%) 

12/48 

5,000 U "-Interferon A/D 1/50 (2%) 

0/50 

1/48 (2%) 

4/48 

5/48 (10%) 

8/48 

4/50 (8%) 

15/50 

a Data are presented as number of vaginal neoplasms/number of animals microscopically examined (first line) and number of vaginal 

hyperplasias/number of animals microscopically examined (second line) b	 Combined incidences of controls from the AZT alone study and the AZT/"-interferon A/D studies; incidences in the vehicle control group from 

the AZT alone study are 0/50 (0%) (neoplasms) and 0/50 (hyperplasia) 

TABLE 28 

Overall Incidence of Renal Tubule Neoplasms in Male Mice in the 2-Year Gavage Studies 

of AZT and AZT/"-Interferon A/Da 

Vehicle Control 30 mg/kg AZT 60 mg/kg AZT 120 mg/kg AZT 

AZT alone 0/198 (0%)b 0/48 (0%) 0/49 (0%) 4/50 (8%) 

500 U "-Interferon A/D 0/50 (0%) 0/50 (0%) 1/50 (2%) 0/50 (0%) 

5,000 U "-Interferon A/D 0/49 (0%) 0/50 (0%) 0/50 (0%) 0/50 (0%) 

a Data are presented as number of renal tubule neoplasms/number of animals examined microscopically b	 Combined incidences of controls from the AZT alone study and the AZT/"-interferon A/D studies; incidence in the vehicle control group 

from the AZT alone study is 0/50 (0%) 

have occurred in groups of control male mice in other mined to be harderian gland neoplasms, were not 

NTP studies. Therefore, the increased incidence in detected in control animals, but were observed in 

renal tubule neoplasms that occurred in male mice four 30 mg/kg, one 60 mg/kg, and nine 120 mg/kg 

receiving 120 mg/kg AZT alone has been judged an animals (Table 29). In addition, the harderian gland 

uncertain finding. Ayers et al. (1996) did not observe was present in routine sections of the nose in about 

any AZT-associated response in male mouse kidneys; 40% of animals from each dose group. Additional 

however, the highest dose used in their 22-month harderian gland neoplasms were observed on 

studies was 40 mg/kg. microscopic examination of routine nose sections in 

males as follows: three in the control group and one 

each in the 30, 60, and 120 mg/kg groups. These 

All animals were observed at necropsy for macro- results reveal an increase in the incidence of harderian 

scopic abnormalities of the harderian gland. In male gland neoplasms in male mice receiving 120 mg/kg 

mice, such abnormalities, later microscopically deter- AZT. 
 

AZT and AZT/"-Interferon A/D, NTP TR 469 81 

TABLE 29 

Overall Incidence of Harderian Gland Neoplasms in Male Mice in the 2-Year Gavage Studies 

of AZT and AZT/"-Interferon A/Da 

Vehicle Control 30 mg/kg AZT 60 mg/kg AZT 120 mg/kg AZT 

AZT alone 13/200 (6%)b 5/50 (10%) 2/50 (4%) 10/50 (20%) 

500 U "-Interferon A/D 6/50 (12%) 3/50 (6%) 1/50 (2%) 4/50 (8%) 

5,000 U "-Interferon A/D 5/50 (10%) 9/50 (18%) 4/50 (8%) 4/50 (8%) 

a Data are presented as number of harderian gland neoplasms/number of animals necropsied b	 Combined incidences of controls from the AZT alone study and the AZT/"-interferon A/D studies; incidence in the vehicle control group 

from the AZT alone study is 3/50 (6%) 

The incidence in this group exceeded the historical A/D or A alone elicit any observable toxic or 

control range for harderian gland neoplasms in carcinogenic response. In contrast to the welluntreated male mice. However, the incidences of characterized antiviral activity of "-interferon A/D in 

harderian gland neoplasms were not increased in mice, its antiproliferative and antineoplastic activities 

a dose-related manner in other groups of male mice. are relatively unknown. Although it displays 

In an extended review of the 120 mg/kg group, antiprolif-erative activity against human neoplasms 

additional sections of the nose and slides of transplanted into nude mice (Gazit et al., 1992), the 

harderian gland prepared from wet tissues of control antiproliferative activity of "-interferon A/D against 

and 120 mg/kg males were examined micro- spontaneous or chemically induced neoplasms in mice 

scopically. As a result of this extended review, has not been demonstrated. 

tissues from 13 control males were found to have 

no additional harderian gland neoplasms, while three The absence of any evidence of immune complex 

additional harderian gland adenomas were found in glomerulonephritis in the kidneys of mice receiving 

27 males receiving 120 mg/kg. However, because "-interferon A/D or A for 2 years suggests that the 

unequal numbers of harderian glands were available animals might not have raised a substantial neutralfor review in each group, the results of the izing antibody response against the human proteins. 

extended review were not included in statistical However, serum antibody titers against "-interferon 

evaluations. A/D were not evaluated. Because a number of factors 

influence the formation of immune complexes and 

The increased incidence of harderian gland neoplasms their deposition in the kidney, the absence of 

in the 120 mg/kg group is suggestive of an association glomerulonephritis cannot be taken as proof that 

with AZT treatment; however, the incidence of neutralizing antibodies were not formed. In addition, 

harderian gland hyperplasia was not increased corre- there is the possibility that the biological activity of 

spondingly in this or other groups administered AZT, interferon dose preparations may have varied considand the incidences of harderian gland neoplasms were erably more than 10%. Although the quantity of 

not increased in a dose-related manner in groups of interferon protein administered to a particular group 

male mice receiving AZT and "-interferon A/D. was the same throughout the 2-year study and all 

Therefore, the increased incidence of harderian gland preparations exhibited antiviral activity, the titer of 

neoplasms in male mice receiving 120 mg/kg was different dose preparations determined with the 

considered an uncertain finding. cytopathic effect assay varied considerably. Part of 

this variability is due to the nature of the assay itself; 

Coadministration of "-interferon A/D had no apparent however, the range of titers observed makes it 

effect on the observed response to AZT treatment in difficult to draw any conclusions about potential 

B6C3F mice, nor did administration of "-interferon effects of interferon coadministration. Therefore, the 1 
 

__________ 

82 AZT and AZT/"-Interferon A/D, NTP TR 469 

apparent lack of effect of coadministration of 

"-interferon A/D must be interpreted with a degree of 

uncertainty. 

The studies reported here and those of Ayers et al. 

(1996) reveal a very consistent response to AZT 

treatment in rodents. Humans metabolize AZT to a 

much greater extent than do rats or mice and no 

comparable situation regarding urine flow into the 

vagina exists in humans. Therefore, if the mechanism 

proposed by Ayers et al. (1996) to explain the 

development of vaginal neoplasms is correct, it is 

uncertain to what extent the results of these studies 

will be predictive of potential human risk. AZT is 

genotoxic both in vitro and in vivo and is a 

particularly potent inducer of micronucleated 

polychromatic erythrocytes in mice (Phillips et al., 

1991). AZT is also an alternate substrate for normal 

cellular DNA polymerases and AZT cytotoxicity is 

strongly correlated to its incorporation into cellular 

DNA. It is somewhat surprising, therefore, that a 

more significant carcinogenic response was not 

observed. 

Based on retrospective analyses, Helicobacter 

hepaticus was determined to have infected mice in 

12 recent NTP 2-year studies (Appendix R). Of the 

12 studies, mice (primarily males) from nine studies 

(including these four studies of AZT and AZT/ 

"-interferon A/D) had a H. hepaticus-associated 

hepatitis. Qualitatively, the hepatitis and silverstaining organisms within the liver were similar 

among the nine studies. Using a polymerase chain 

reaction-restriction fragment length polymorphism 

(PCR-RFLP)-based assay, H. hepaticus was identified 

in studies from which adequately preserved (frozen) 

liver tissue was available, including 11 of 20 animals 

from the study of AZT. In general, efforts to identify 

H. hepaticus from tissue fixed in formalin for over a 

week were not successful (Malarkey et al., 1997), 

which was the case for the studies of 

"-interferon A/D, AZT/500 U "-interferon A/D, and 

AZT/5,000 U "-interferon A/D, for which frozen 

liver tissue was not available. However, because of 

the presence of the typical liver lesions, silver-staining 

helical organisms, and confirmation with PCR-RFLPbased assays in the AZT study, the mice from all 

these studies were presumed to be infected with 

H. hepaticus. 

Increases in the incidences of hepatocellular neoplasms in male mice have been shown to be associated 

with H. hepaticus infection when hepatitis is also 

present (Ward et al., 1994; Fox et al., 1996; 

Appendix R). Additionally, in NTP studies with 

H. hepaticus-associated hepatitis, increased incidences 

of hemangiosarcoma were seen in the livers of male 

mice (Appendix R). However, there was no 

consistent response in the liver of male mice in any of 

these four studies. Therefore, detection of doserelated differences in incidences of neoplasms in these 

four studies was not considered to have been 

significantly impacted by the infection with 

H. hepaticus or its associated hepatitis (Appendix R). 

CONCLUSIONS 

Under the conditions of these 2-year gavage studies 

there was equivocal evidence of carcinogenic activity* 

of AZT in male mice based on increased incidences of 

renal tubule and harderian gland neoplasms in groups 

receiving AZT alone. There was clear evidence of 

carcinogenic activity of AZT in female mice based on 

increased incidences of squamous cell neoplasms of 

the vagina in groups that received AZT alone or in 

combination with "-interferon A/D. 

Hematotoxicity occurred in all groups that received 

AZT. 

Treatment with AZT alone and AZT in combination 

with "-interferon A/D resulted in increased incidences 

of epithelial hyperplasia of the vagina in all dosed 

groups of females. 

* Explanation of Levels of Evidence of Carcinogenic Activity is on page 14. A summary of the Technical Reports Review Subcommittee 

comments and the public discussion on this Technical Report appears on page 16. 
83 

REFERENCES
 

Abenoza, P., Manivel, J.C., Wick, M.R., Hagen, K., 

and Dehner, L.P. (1987). Hepatoblastoma: An 

immunohistochemical and ultrastructural study. Hum. 

Pathol. 18, 1025-1035. 

Adolf, G.R., Frühbeis, B., Hauptmann, R., 

Kalsner, I., Maurer-Fogy, I., Ostermann, E., 

Patzelt, E., Schwendenwein, R., Sommergruber, W., 

and Zöphel, A. (1991). Human interferon T1: Isolation of the gene, expression in Chinese hamster ovary 

cells and characterization of the recombinant protein. 

Biochim. Biophys. Acta 1089, 167-174. 

American Hospital Formulary Service (AHFS) (1997) 

AHFS 97 Drug Information. (G.K. McEvoy, 

K. Litvak, and O.H. Welsh, Jr., Eds.), pp. 538-557. 

American Society of Health-System Pharmacists, Inc., 

Bethesda, MD. 

Anonymous (1987). Zidovudine approved by FDA 

for treatment of AIDS. Clin. Pharm. 6, 431, 435. 

Armitage, P. (1971). Statistical Methods in Medical 

Research, pp. 362-365. John Wiley and Sons, New 

York. 

Ashby, J., and Tennant, R.W. (1991). Definitive 

relationships among chemical structure, 

carcinogenicity and mutagenicity for 301 chemicals 

tested by the U.S. NTP. Mutat. Res. 257, 229-306. 

Ayers, K.M. (1988). Preclinical toxicology of 

zidovudine. An overview. Am. J. Med. 85 

(Suppl. 2A), 186-188. 

Ayers, K.M., Clive, D., Tucker, W.E., Jr., 

Hajian, G., and de Miranda, P. (1996). Nonclinical 

toxicology studies with zidovudine: Genetic toxicity 

tests and carcinogenicity bioassays in mice and rats. 

Fundam. Appl. Toxicol. 32, 148-158. 

Balzarini, J. (1994). Metabolism and mechanism of 

antiretroviral action of purine and pyrimidine derivatives. Pharm. World Sci. 16, 113-126. 

Bender, M.A., Preston, R.J., Leonard, R.C., 

Pyatt, B.E., Gooch, P.C., and Shelby, M.D. (1988). 

Chromosomal aberration and sister-chromatid 

exchange frequencies in peripheral blood lymphocytes 

of a large human population sample. Mutat. Res. 

204, 421-433. 

Bocci, V., Pacini, A., Muscettola, M., Pessina, G.P., 

Paulesu, L., and Bandinelli, L. (1982). The kidney 

is the main site of interferon catabolism. J. Interferon 

Res. 2, 309-314. 

Boorman, G.A., Montgomery, C.A., Jr., 

Eustis, S.L., Wolfe, M.J., McConnell, E.E., and 

Hardisty, J.F. (1985). Quality assurance in pathology 

for rodent carcinogenicity studies. In Handbook of 

Carcinogen Testing (H.A. Milman and 

E.K. Weisburger, Eds.), pp. 345-357. Noyes 

Publications, Park Ridge, NJ. 

Brunda, M.J., and Rosenbaum, D. (1984). Modulation of murine natural killer cell activity in vitro and 

in vivo by recombinant human interferons. Cancer 

Res. 44, 597-601. 

Capon, D.J., Shepard, H.M., and Goeddel, D.V. 

(1985). Two distinct families of human and bovine 

interferon-" genes are coordinately expressed and 

encode functional polypeptides. Mol. Cell. Biol. 5, 

768-779. 

Child, S., Montaner, J., Tsoukas, C., Fanning, M., 

Le, T., Wall, R.A., and Ruedy, J. (1991). Canadian 

multicenter azidothymidine trial: AZT 

pharmacokinetics. J. Acquir. Immune Defic. Syndr. 

4, 865-870. 
84 AZT and AZT/"-Interferon A/D, NTP TR 469 

Cid, M.G., and Larripa, I. (1994). Genotoxic activity 

of azidothymidine (AZT) in in vitro systems. Mutat. 

Res. 321, 113-118. 

Code of Federal Regulations (CFR) 21, Part 58. 

Cox, D.R. (1972). Regression models and life-tables. 

J. R. Stat. Soc. B34, 187-220. 

Crawford, B.D. (1985). Perspectives on the somatic 

mutation model of carcinogenesis. In Advances in 

Modern Environmental Toxicology: Mechanisms and 

Toxicity of Chemical Carcinogens and Mutagens 

(M.A. Mehlman, W.G. Flamm, and R.J. Lorentzen, 

Eds.), pp. 13-59. Princeton Scientific Publishing 

Co., Inc., Princeton, NJ. 

Cretton, E.M., Schinazi, R.F., McClure, H.M., 

Anderson, D.C., and Sommadossi, J.-P. (1991a). 

Pharmacokinetics of 3N-azido-3N-deoxythymidine and 

its catabolites and interactions with probenecid in 

rhesus monkeys. Antimicrob. Agents Chemother. 35, 

801-807. 

Cretton, E.M., Xie, M.-Y., Bevan, R.J., 

Goudgaon, N.M., Schinazi, R.F., and 

Sommadossi, J.-P. (1991b). Catabolism of 3N-azido3N-deoxythymidine in hepatocytes and liver 

microsomes, with evidence of formation of 3N-amino3N-deoxythymidine, a highly toxic catabolite for 

human bone marrow cells. Mol. Pharmacol. 39, 

258-266. 

Dainiak, N., Worthington, M., Riordan, M.A., 

Kreczko, S., and Goldman, L. (1988). 3N-Azido3N-deoxythymidine (AZT) inhibits proliferation 

in vitro of human haematopoietic progenitor cells. 

Br. J. Haematol. 69, 299-304. 

Dalakas, M.C., Illa, I., Pezeshkpour, G.H., 

Laukaitis, J.P., Cohen, B., and Griffin, J.L. (1990). 

Mitochondrial myopathy caused by long-term 

zidovudine therapy. N. Engl. J. Med. 322, 

1098-1105. 

David, M. (1995). Transcription factors in interferon 

signaling. Pharmacol. Ther. 65, 149-161. 

Dinse, G.E., and Haseman, J.K. (1986). Logistic 

regression analysis of incidental-tumor data from 

animal carcinogenicity experiments. Fundam. Appl. 

Toxicol. 6, 44-52. 

Dinse, G.E., and Lagakos, S.W. (1983). Regression 

analysis of tumour prevalence data. Appl. Statist. 32, 

236-248. 

Dixon, W.J., and Massey, F.J., Jr. (1951). 

Introduction to Statistical Analysis, 1st ed., 

pp. 145-147. McGraw-Hill Book Company, Inc., 

New York. 

Doshi, K.J., Gallo, J.M., Boudinot, F.D., 

Schinazi, R.F., and Chu, C.K. (1989). Comparative 

pharmacokinetics of 3N-azido-3N-deoxythymidine 

(AZT) and 3N-azido-2N,3N-dideoxyuridine (AZddU) in 

mice. Drug Metab. Dispos. 17, 590-594. 

Dubreuil, M., Sportza, L., D’Addario, M., 

Lacoste, J., Rooke, R., Wainberg, M.A., and 

Hiscott, J. (1990). Inhibition of HIV-1 transmission 

by interferon and 3N-azido-3N-deoxythymidine during 

de novo infection of promonocytic cells. Virology 

179, 388-394. 

Dunn, A.L., and Crnic, L.S. (1993). Repeated injections of interferon-" A/D in Balb/c mice: Behavioral 

effects. Brain Behav. Immun. 7, 104-111. 

Dunn, O.J. (1964). Multiple comparisons using rank 

sums. Technometrics 6, 241-252. 

Dunnett, C.W. (1955). A multiple comparison procedure for comparing several treatments with a control. 

J. Am. Stat. Assoc. 50, 1096-1121. 

Fent K., and Zbinden, G. (1988). Nephrotoxicity 

screening in rats: A validation study. Arch. Toxicol. 

61, 349-358. 

Fischl, M.A. (1989). State of antiretroviral therapy 

with zidovudine. AIDS 3, S137-S143. 

Fowler, D.A., Weidner, D.A., and 

Sommadossi, J.-P. (1995). Effects of 3N-azido-3Ndeoxythymidine on erythroid inducible gene expression in human K-562 leukemia cells. Toxicol. Lett. 

80, 139-146. 
AZT and AZT/"-Interferon A/D, NTP TR 469 85 

Fox, J.G., Li, X., Yan, L., Cahill, R.J., Hurley, R., 

Lewis, R., and Murphy, J.C. (1996). Chronic proliferative hepatitis in A/JCr mice associated with 

persistent Helicobacter hepaticus infection: A model 

of helicobacter-induced carcinogenesis. Infect. 

Immun. 64, 1548-1558. 

Furman, P.A., Fyfe, J.A., St. Clair, M.H., 

Weinhold, K., Rideout, J.L., Freeman, G.A., 

Lehrman, S.N., Bolognesi, D.P., Broder, S., 

Mitsuya, H., and Barry, D.W. (1986). Phosphorylation of 3N-azido-3N-deoxythymidine and selective 

interaction of the 5N-triphosphate with human 

immunodeficiency virus reverse transcriptase. Proc. 

Natl. Acad. Sci. USA 83, 8333-8337. 

Gallicchio, V.S., Doukas, M.A., Hulette, B.C., 

Hughes, N.K., and Gass, C. (1989). Protection of 

3N-azido-3N-deoxythymidine induced toxicity to murine 

hematopoietic progenitors (CFU-GM, BFU-E and 

CFU-MEG) with interleukin-1. Proc. Soc. Exp. Biol. 

Med. 192, 201-204. 

Galloway, S.M., Armstrong, M.J., Reuben, C., 

Colman, S., Brown, B., Cannon, C., Bloom, A.D., 

Nakamura, F., Ahmed, M., Duk, S., Rimpo, J., 

Margolin, B.H., Resnick, M.A., Anderson, B., and 

Zeiger, E. (1987). Chromosome aberrations and 

sister chromatid exchanges in Chinese hamster ovary 

cells: Evaluations of 108 chemicals. Environ. Mol. 

Mutagen. 10 (Suppl. 10), 1-175. 

Gart, J.J., Chu, K.C., and Tarone, R.E. (1979). 

Statistical issues in interpretation of chronic bioassay 

tests for carcinogenicity. JNCI 62, 957-974. 

Gazit, Z., Weiss, D.W., Shouval, D., 

Yechezkeli, M., Schirrmacher, V., Notter, M., 

Walter, J., and Kedar, E. (1992). Chemo-adoptive 

immunotherapy of nude mice implanted with human 

colorectal carcinoma and melanoma cell lines. 

Cancer Immunol. Immunother. 35, 135-144. 

Good, S.S., Koble, C.S., Crouch, R., Johnson, R.L., 

Rideout, J.L., and de Miranda, P. (1990). Isolation 

and characterization of an ether glucuronide of 

zidovudine, a major metabolite in monkeys and 

humans. Drug Metab. Dispos. 18, 321-326. 

Greig, N.H., Soncrant, T.T., Wozniak, K.M., and 

Rapoport, S.I. (1988). Plasma and tissue pharmacokinetics of human interferon-alpha in the rat after its 

intravenous administration. J. Pharmacol. Exp. Ther. 

245, 574-580. 

Greischel, A., Tanswell, P., Busch, U., and 

Schumacher, K. (1988). Pharmacokinetics and 

biodisposition of recombinant human interferon-"2C 

in rat and marmoset. Arzneimittelforschung 38, 

1539-1543. 

Hartshorn, K.L., Neumeyer, D., Vogt, M.W., 

Schooley, R.T., and Hirsch, M.S. (1987a). Activity 

of interferons alpha, beta, and gamma against human 

immunodeficiency virus replication in vitro. AIDS 

Res. Hum. Retroviruses 3, 125-133. 

Hartshorn, K.L., Vogt, M.W., Chou, T.C., 

Blumberg, R.S., Byington, R., Schooley, R.T., and 

Hirsch, M.S. (1987b). Synergistic inhibition of 

human immunodeficiency virus in vitro by azidothymidine and recombinant alpha A interferon. 

Antimicrob. Agents Chemother. 31, 168-172. 

Haseman, J.K. (1984). Statistical issues in the 

design, analysis and interpretation of animal carcinogenicity studies. Environ. Health Perspect. 58, 

385-392. 

Hauptmann, R., and Swetly, P. (1985). A novel class 

of human type I interferons. Nucleic Acids Res. 13, 

4739-4749. 

Ho, D.D., Hartshorn, K.L., Rota, T.R., 

Andrews, C.A., Kaplan, J.C., Schooley, R.T., and 

Hirsch, M.S. (1985). Recombinant human interferon 

alfa-A suppresses HTLV-III replication in vitro. 

Lancet 1, 602-604. 

Hollander, M., and Wolfe, D.A. (1973). Nonparametric Statistical Methods, pp. 120-123. John 

Wiley and Sons, New York. 
 

86 AZT and AZT/"-Interferon A/D, NTP TR 469 

Horisberger, M.A., and Di Marco, S. (1995). Interferon-alpha hybrids. Pharmacol. Ther. 66, 507-534. 

Horwitz, J.P., Chua, J., and Noel, M. (1964). 

Nucleosides. V. The monomesylates of 1-(2N-deoxy­

-D-lyxofuranosyl)thymine. J. Org. Chem. 29, 

2076-2078. 

Huang, P., Farquhar, D., and Plunkett, W. (1990). 

Selective action of 3N-azido-3N-deoxythymidine 

5N-triphosphate on viral reverse transcriptases and 

human DNA polymerases. J. Biol. Chem. 265, 

11,914-11,918. 

Hwang, S.Y., Hertzog, P.J., Holland, K.A., 

Sumarsono, S.H., Tymms, M.J., Hamilton, J.A., 

Whitty, G., Bertoncello, I., and Kola, I. (1995). A 

null mutation in the gene encoding a type I interferon 

receptor component eliminates antiproliferative and 

antiviral responses to interferons " and and alters 

macrophage responses. Proc. Natl. Acad. Sci. USA 

92, 11,284-11,288. 

Johns, T.G., Kerry, J.A., Veitch, B.A., 

Mackay, I.R., Tutton, P.J., Tymms, M.J., 

Cheetham, B.F., Hertzog, P.J., and Linnane, A.W. 

(1990). Pharmacokinetics, tissue distribution, and cell 

35 localization of [ S]methionine-labeled recombinant 

human and murine " interferons in mice. Cancer 

Res. 50, 4718-4723. 

Jonckheere, A.R. (1954). A distribution-free 

k-sample test against ordered alternatives. Biometrika 

41, 133-145. 

Kaplan, E.L., and Meier, P. (1958). Nonparametric 

estimation from incomplete observations. J. Am. Stat. 

Assoc. 53, 457-481. 

Kerry, J.A., Johns, T.G., Linnane, A.W., and 

Cheetham, B.F. (1993). Amino acid substitutions 

alter the tissue distribution of murine interferon-"1. 

J. Interferon Res. 13, 143-151. 

Krown, S.E. (1990). Approaches to interferon combination therapy in the treatment of AIDS. Semin. 

Oncol. 17, 11-15. 

Lamperth, L., Dalakas, M.C., Dagani, F., 

Anderson, J., and Ferrari, R. (1991). Abnormal 

skeletal and cardiac muscle mitochondria induced by 

zidovudine (AZT) in human muscle in vitro and in an 

animal model. Lab. Invest. 65, 742-751. 

Lane, H.C. (1989). The role of immunomodulators 

in the treatment of patients with AIDS. AIDS 3, 

S181-S185. 

Lane, H.C., Davey, V., Kovacs, J.A., Feinberg, J., 

Metcalf, J.A., Herpin, B., Walker, R., Deyton, L., 

Davey, R.T., Jr., Falloon, J., Polis, M.A., 

Salzman, N.P., Baseler, M., Masur, H., and 

Fauci, A.S. (1990). Interferon-" in patients with 

asymptomatic human immunodeficiency virus (HIV) 

infection. A randomized, placebo-controlled trial. 

Ann. Intern. Med. 112, 805-811. 

Lave, T., Levet-Trafit, B., Schmitt-Hoffmann, A.H., 

Morgenroth, B., Richter, W., and Chou, R.C. 

(1995). Interspecies scaling of interferon disposition 

and comparison of allometric scaling with 

concentration–time transformations. J. Pharm. Sci. 

84, 1285-1290. 

Lewis, W., Gonzalez, B., Chomyn, A., and 

Papoian, T. (1992). Zidovudine induces molecular, 

biochemical, and ultrastructural changes in rat skeletal 

muscle mitochondria. J. Clin. Invest. 89, 1354-1360. 

Lewis, W., Simpson, J.F., and Meyer, R.R. (1994). 

Cardiac mitochondrial DNA polymerase- is inhibited 

competitively and noncompetitively by phosphorylated 

zidovudine. Circ. Res. 74, 344-348. 

McConnell, E.E., Solleveld, H.A., Swenberg, J.A., 

and Boorman, G.A. (1986). Guidelines for combining neoplasms for evaluation of rodent carcinogenesis studies. JNCI 76, 283-289. 

MacGregor, J.T., Wehr, C.M., Henika, P.R., and 

Shelby, M.D. (1990). The in vivo erythrocyte micronucleus test: Measurement at steady state increases 

assay efficiency and permits integration with toxicity 

studies. Fundam. Appl. Toxicol. 14, 513-522. 
AZT and AZT/"-Interferon A/D, NTP TR 469 87 

McKnight, B., and Crowley, J. (1984). Tests for 

differences in tumor incidence based on animal 

carcinogenesis experiments. J. Am. Stat. Assoc. 79, 

639-648. 

De Maeyer, E., and De Maeyer-Guignard, J. (1998). 

Interferons. In The Cytokine Handbook 

(A.W. Thomson, Ed.), 3rd ed., pp. 494-516. 

Academic Press, San Diego. 

Malarkey, D.E., Ton, T.-V., Hailey, J.R., and 

Devereux, T.R. (1997). A PCR-RFLP method for 

the detection of Helicobacter hepaticus in frozen or 

fixed liver from B6C3F mice. Toxicol. Pathol. 25, 1 

606-612. 

Margolin, B.H., Risko, K.J., Frome, E.L., and 

Tice, R.R. (1990). A general purpose statistical 

analysis program for micronucleus assay data. 

Appendix 2: Micronucleus data management and 

analysis version 1.4a. Integrated Laboratory Systems, 

Research Triangle Park, NC. 

Maronpot, R.R., and Boorman, G.A. (1982). 

Interpretation of rodent hepatocellular proliferative 

alterations and hepatocellular tumors in chemical 

safety assessment. Toxicol. Pathol. 10, 71-80. 

Mays, D.C., Dixon, K.F., Balboa, A., Pawluk, L.J., 

Bauer, M.R., Nawoot, S., and Gerber, N. (1991). A 

nonprimate animal model applicable to zidovudine 

pharmacokinetics in humans: Inhibition of glucuronidation and renal excretion of zidovudine by probenecid in rats. J. Pharmacol. Exp. Ther. 259, 

1261-1270. 

Miller, J.A., and Miller, E.C. (1977). Ultimate 

chemical carcinogens as reactive mutagenic electrophiles. In Origins of Human Cancer (H.H. Hiatt, 

J.D. Watson, and J.A. Winsten, Eds.), pp. 605-627. 

Cold Spring Harbor Laboratory, Cold Spring Harbor, 

NY. 

de Miranda, P., Burnette, T.C., and Good, S.S. 

(1990). Tissue distribution and metabolic disposition 

of zidovudine in rats. Drug Metab. Dispos. 18, 

315-320. 

Mitsuya, H., Weinhold, K.J., Furman, P.A., 

St. Clair, M.H., Lehrman, S.N., Gallo, R.C., 

Bolognesi, D., Barry, D.W., and Broder, S. (1985). 

3N-Azido-3N-deoxythymidine (BW A509U): An antiviral agent that inhibits the infectivity and cytopathic 

effect of human T-lymphotropic virus type III/ 

lymphadenopathy-associated virus in vitro. Proc. 

Natl. Acad. Sci. USA 82, 7096-7100. 

Morrison, D.F. (1976). Multivariate Statistical 

Methods, 2nd ed., pp. 170-179. McGraw-Hill Book 

Company, New York. 

Motimaya, A.M., Subramanya, K.S., Curry, P.T., 

and Kitchin, R.M. (1994). Lack of induction of 

micronuclei by azidothymidine (AZT) in vivo in 

mouse bone marrow cells. Environ. Mol. Mutagen. 

23, 74-76. 

Müller, U., Steinhoff, U., Reis, L.F., Hemmi, S., 

Pavlovic, J., Zinkernagel, R.M., and Aguet, M. 

(1994). Functional role of type I and type II interferons in antiviral defense. Science 264, 1918-1921. 

National Cancer Institute (NCI) (1976). Guidelines 

for Carcinogen Bioassay in Small Rodents. Technical 

Report Series No. 1. NIH Publication No. 76-801. 

U.S. Department of Health, Education, and Welfare, 

Public Health Service, National Institutes of Health, 

Bethesda, MD. 

National Institutes of Health (NIH) (1978). Open 

Formula Rat and Mouse Ration (NIH-07). 

Specification NIH-11-1335. U.S. Department of 

Health, Education, and Welfare, Public Health 

Service, NIH, Bethesda, MD. 

National Toxicology Program (NTP) (1987). 

Technical Protocol for Sperm Morphology and 

Vaginal Cytology Evaluations in Toxicity Testing for 

Rats and Mice, 10/31/82 version (updated December 

1987). Research Triangle Park, NC. 

Nicolas, F., De Sousa, G., Thomas, P., Placidi, M., 

Lorenzon, G., and Rahmani, R. (1995). Comparative 

metabolism of 3N-azido-3N-deoxythymidine in cultured 

hepatocytes from rats, dogs, monkeys, and humans. 

Drug Metab. Dispos. 23, 308-313. 
88 AZT and AZT/"-Interferon A/D, NTP TR 469 

Nonoyama, T., Fullerton, F., Reznik, G.,
 

Bucci, T.J., and Ward, J.M. (1988). Mouse hepatoblastomas: A histologic, ultrastructural, and 

immunohistochemical study. Vet. Pathol. 25, 

286-296. 

Oleson, F.B., and Getman, S.M. (1990). Multipledose erythrocyte micronucleus assays in mice and rats
 

with azidothymidine (AZT). Environ. Mol. Mutagen.
 

15 (Suppl. 17), 46 (Abstr.).
 

Olin, B.R., and Kastrup, E.K. (1995). Drug Facts
 

and Comparisons, p. 404c. Facts and Comparisons,
 

Inc., St. Louis, MO.
 

Ortaldo, J.R., Mason, A., Rehberg, E., Moschera, J.,
 

Kelder, B., Pestka, S., and Herberman, R.B. (1983).
 

Effects of recombinant and hybrid recombinant human
 

leukocyte interferons on cytotoxic activity of natural
 

killer cells. J. Biol. Chem. 258, 15011-15015.
 

Panzer, S., Stain, C., Benda, H., and Mannhalter, C.
 

(1989). Effects of 3-azidothymidine on platelet
 

counts, indium-111-labelled platelet kinetics, and antiplatelet antibodies. Vox. Sang. 57, 120-126.
 

Parker, W.B., White, E.L., Shaddix, S.C.,
 

Ross, L.J., Buckheit, R.W., Jr., Germany, J.M.,
 

Secrist, J.A., III, Vince, R., and Shannon, W.M.
 

(1991). Mechanism of inhibition of human immunodeficiency virus type 1 reverse transcriptase
 

and human DNA polymerases ", , and by
 

the 5N-triphosphates of carbovir, 3N-azido3N-deoxythymidine, 2N,3N-dideoxyguanosine and
 

3N-deoxythymidine. A novel RNA template for the
 

evaluation of antiretroviral drugs. J. Biol. Chem.
 

266, 1754-1762.
 

Patel, B.A., Chu, C.K., and Boudinot, F.D. (1989).
 

Pharmacokinetics and saturable renal tubular secretion
 

of zidovudine in rats. J. Pharm. Sci. 78, 530-534.
 

Pestka, S. (1983). The human interferons — from
 

protein purification and sequence to cloning and
 

expression in bacteria: Before, between, and beyond.
 

Arch. Biochem. Biophys. 221, 1-37.
 

Pestka, S., Langer, J.A., Zoon, K.C., and
 

Samuel, C.E. (1987). Interferons and their actions.
 

Annu. Rev. Biochem. 56, 727-777.
 

Phillips, M.D., Nascimbeni, B., Tice, R.R., and 

Shelby, M.D. (1991). Induction of micronuclei in 

mouse bone marrow cells: An evaluation of nucleoside analogues used in the treatment of AIDS. 

Environ. Mol. Mutagen. 18, 168-183. 

Placidi, L., Cretton, E.M., Placidi, M., and 

Sommadossi, J.-P. (1993). Reduction of 3N-azido3N-deoxythymidine to 3N-amino-3N-deoxythymidine in 

human liver microsomes and its relationship to cytochrome P450. Clin. Pharmacol. Ther. 54, 168-176. 

Pluda, J.M., Mitsuya, H., and Yarchoan, R. (1991). 

Hematologic effects of AIDS therapies. Hematol. 

Oncol. Clin. North Am. 5, 229-248. 

Poli, G., Biswas, P., and Fauci, A.S. (1994). Interferons in the pathogenesis and treatment of human 

immunodeficiency virus infection. Antiviral Res. 24, 

221-233. 

Rosenberg, H., Madar, Z., Gertler, A., 

Rubinstein, M., and Bino, T. (1985). The 

fate of [125I]-labeled human leukocyte-derived 

alpha interferon in the rat. J. Interferon Res. 5, 

121-127. 

Rosenthal, G.J., Stranahan, R.P., III, Thompson, M., 

Blair, P., Germolec, D.R., Comment, C.E., 

Schwab, K., and Luster, M.I. (1990). Organ-specific 

hematopoietic changes induced by a recombinant 

human interferon-" in mice. Fundam. Appl. Toxicol. 

14, 666-675. 

Ruprecht, R.M., Chou, T.-C., Chipty, F., 

Sosa, M.G., Mullaney, S., O’Brien, L., and 

Rosas, D. (1990). Interferon-" and 3N-azido-3Ndeoxythymidine are highly synergistic in mice 

and prevent viremia after acute retrovirus exposure. 

J. Acquir. Immune Defic. Syndr. 3, 591-600. 

Sadtler Standard Spectra. IR No. R421. Sadtler 

Research Laboratories, Philadelphia. 

Schindler, C., and Darnell, J.E., Jr. (1995). 

Transcriptional responses to polypeptide ligands: The 

JAK-STAT pathway. Annu. Rev. Biochem. 64, 

621-651. 
AZT and AZT/"-Interferon A/D, NTP TR 469 89 

Shafik, H.M., Nokta, M.A., and Pollard, R.B. 

(1991). Recombinant human interferon beta ser 

protects against zidovudine-induced genetic damage 

in AIDS patients. Antiviral Res. 16, 205-212. 

Shelby, M.D., and Witt, K.L. (1995). Comparison of 

results from mouse bone marrow chromosome aberration and micronucleus tests. Environ. Mol. Mutagen. 

25, 302-313. 

Shelby, M.D., Erexson, G.L., Hook, G.J., and 

Tice, R.R. (1993). Evaluation of a three-exposure 

mouse bone marrow micronucleus protocol: Results 

with 49 chemicals. Environ. Mol. Mutagen. 21, 

160-179. 

Shirley, E. (1977). A non-parametric equivalent of 

Williams’ test for contrasting increasing dose levels of 

a treatment. Biometrics 33, 386-389. 

Simpson, M.V., Chin, C.D., Keilbaugh, S.A., 

Lin, T.S., and Prusoff, W.H. (1989). Studies 

on the inhibition of mitochondrial DNA 

replication by 3N-azido-3N-deoxythymidine and 

other dideoxynucleoside analogs which inhibit 

HIV-1 replication. Biochem. Pharmacol. 38, 

1033-1036. 

Singlas, E., Pioger, J.C., Taburet, A.M., 

Colaneri, S., and Fillastre, J.P. (1989). Comparative 

pharmacokinetics of zidovudine (AZT) and its metabolite (G.AZT) in healthy subjects and HIV seropositive patients. Eur. J. Clin. Pharmacol. 36, 

639-640. 

Sommadossi, J.-P., and Carlisle, R. (1987). Toxicity 

of 3N-azido-3N-deoxythymidine and 9-(1,3-dihydroxy2-propoxymethyl)guanine for normal human hematopoietic progenitor cells in vitro. Antimicrob. Agents 

Chemother. 31, 452-454. 

Sommadossi, J.-P., Zhu, Z., and Carlisle, R. (1987). 

Mechanism of toxicity of 3N-azido-3N-deoxythymidine 

(AZT) in normal hematopoietic progenitor (HP) cells. 

Evidence of inhibition of the de novo pyrimidine 

pathway. Proc. Annu. Meet. Am. Assoc. Cancer Res. 

28, 329 (Abstr.). 

Sommadossi, J.-P., Carlisle, R., and Zhou, Z. 

(1989). Cellular pharmacology of 3N-azido-3N-deoxythymidine with evidence of incorporation into DNA of 

human bone marrow cells. Mol. Pharmacol. 36, 

9-14. 

SRI International (1987). SRI International Report, 

Life Sciences Division, AZT (Lot No. 85/0567­

044-H, SRI No. A70). 

Spiegel, R.J. (1987). Clinical overview of alpha 

interferon. Studies and future directions. Cancer 59, 

626-631. 

Stagg, M.P., Cretton, E.M., Kidd, L., Diasio, R.B., 

and Sommadossi, J.-P. (1992). Clinical pharmacokinetics of 3N-azido-3N-deoxythymidine (zidovudine) 

and catabolites with formation of a toxic catabolite, 

3N-amino-3N-deoxythymidine. Clin. Pharmacol. Ther. 

51, 668-676. 

Straus, D.S. (1981). Somatic mutation, cellular differentiation, and cancer causation. JNCI 67, 233-241. 

Taburet, A.-M., Naveau, S., Zorza, G., Colin, J.-N., 

Delfraissy, J.-F., Chaput, J.-C., and Singlas, E. 

(1990). Pharmacokinetics of zidovudine in patients 

with liver cirrhosis. Clin. Pharmacol. Ther. 47, 

731-739. 

Tarone, R.E. (1975). Tests for trend in life table 

analysis. Biometrika 62, 679-682. 

Tennant, R.W., Margolin, B.H., Shelby, M.D., 

Zeiger, E., Haseman, J.K., Spalding, J., 

Caspary, W., Resnick, M., Stasiewicz, S., 

Anderson, B., and Minor, R. (1987). Prediction of 

chemical carcinogenicity in rodents from in vitro 

genetic toxicity assays. Science 236, 933-941. 

Thompson, M.B., Dunnick, J.K., Sutphin, M.E., 

Giles, H.D., Irwin, R.D., and Prejean, J.D. (1991). 

Hematologic toxicity of AZT and ddC administered as 

single agents and in combination to rats and mice. 

Fundam. Appl. Toxicol. 17, 159-176. 
90 AZT and AZT/"-Interferon A/D, NTP TR 469 

Trang, J.M., Prejean, J.D., James, R.H., 

Irwin, R.D., Goehl, T.J., and Page, J.G. (1993). 

Zidovudine bioavailability and linear pharmacokinetics in female B6C3F1 mice. Drug Metab. 

Dispos. 21, 189-193. 

Turusov, V.S., Deringer, M.K., Dunn, T.B., and 

Stewart, H.L. (1973). Malignant mouse-liver tumors 

resembling human hepatoblastomas. J. Natl. Cancer 

Inst. 51, 1689-1695. 

Van Eyken, P., Sciot, R., Callea, F., Ramaekers, F., 

Schaart, G., and Desmet, V.J. (1990). A cytokeratinimmunohistochemical study of hepatoblastoma. Hum. 

Pathol. 21, 302-308. 

Ward, J.M., Fox, J.G., Anver, M.R., Haines, D.C., 

George, C.V., Collins, M.J., Jr., Gorelick, P.L., 

Nagashima, K., Gonda, M.A., Gilden, R.V., 

Tully, J.G., Russell, R.J., Benveniste, R.E., 

Paster, B.J., Dewhirst, F.E., Donovan, J.C., 

Anderson, L., and Rice, J.M. (1994). Chronic active 

hepatitis and associated liver tumors in mice caused 

by a persistent bacterial infection with a novel 

Helicobacter species. J. Natl. Cancer Inst. 86, 

1222-1227. 

Weidner, D.A., and Sommadossi, J.-P. (1990). 

3N-Azido-3N-deoxythymidine inhibits globin gene 

ranscription in butyric acid-induced K-562 

uman leukemia cells. Mol. Pharmacol. 38, 797-804. 

Wientjes, M.G., and Au, J.L. (1992). Lack 

of pharmacokinetic interaction between 

intravenous 2N,3N-dideoxyinosine and 3N-azido-3Ndeoxythymidine in rats. Antimicrob. Agents 

Chemother. 36, 665-668. 

Williams, D.A. (1971). A test for differences 

between treatment means when several dose levels are 

compared with a zero dose control. Biometrics 27, 

103-117. 

Williams, D.A. (1972). The comparison of several 

dose levels with a zero dose control. Biometrics 28, 

519-531. 

Wills, R.J. (1990). Clinical pharmacokinetics of 

interferons. Clin. Pharmacokinet. 19, 390-399. 

Yamamoto, J.K., Barre-Sinoussi, F., Bolton, V., 

Pedersen, N.C., and Gardner, M.B. (1986). Human 

alpha- and beta-interferon but not gamma- suppress 

the in vitro replication of LAV, HTLV-III, and 

ARV-2. J. Interferon Res. 6, 143-152. 

Yarchoan, R., Klecker, R.W., Weinhold, K.J., 

Markham, P.D., Lyerly, H.K., Durack, D.T., 

Gelmann, E., Lehrman, S.N., Blum, R.M., 

Barry, D.W., Shearer, G.M., Mitsuya, H., 

Collins, J.M., Myers, C.E., Klecker, R.W., 

Fischl, M.A., Gallo, R.C., Bolognesi, D.P., and 

Broder, S. (1986). Administration of 3N-azido3N-deoxythymidine, an inhibitor of HTLV-III/LAV 

replication, to patients with AIDS or AIDS-related 

complex. Lancet 1, 575-580. 

Zeiger, E., Haseman, J.K., Shelby, M.D., 

Margolin, B.H., and Tennant, R.W. (1990). Evaluation of four in vitro genetic toxicity tests for 

predicting rodent carcinogenicity: Confirmation of 

earlier results with 41 additional chemicals. Environ. 

Mol. Mutagen. 16 (Suppl. 18), 1-14. 

Zeiger, E., Anderson, B., Haworth, S., Lawlor, T., 

and Mortelmans, K. (1992). Salmonella mutagenicity 

tests: V. Results from the testing of 311 chemicals. 

Environ. Mol. Mutagen. 19 (Suppl. 21), 2-141. 

Zimmerman, T.P., Mahoney, W.B., and Prus, K.L. 

(1987). 3N-Azido-3N-deoxythymidine. An unusual 

nucleoside analogue that permeates the membrane of 

human erythrocytes and lymphocytes by nonfacilitated 

diffusion. J. Biol. Chem. 262, 5748-5754. 
91 

APPENDIX A
 

SUMMARY OF LESIONS IN MALE MICE
 

IN THE 2-YEAR GAVAGE STUDY
 

OF AZT
 

TABLE A1 Summary of the Incidence of Neoplasms in Male Mice 

in the 2-Year Gavage Study of AZT .................................... 92
 

TABLE A2 Statistical Analysis of Primary Neoplasms in Male Mice 

TABLE A3a Historical Incidence of Renal Tubule Neoplasms 

in the 2-Year Gavage Study of AZT .................................... 96
 

in Water Gavage Vehicle Control Male B6C3F1 Mice ......................... 101
 

TABLE A3b	 Historical Incidence of Harderian Gland Neoplasms 

in Water Gavage Vehicle Control Male B6C3F1 Mice ......................... 101
 

TABLE A3c	 Historical Incidence of Liver Neoplasms 

in Water Gavage Vehicle Control Male B6C3F1 Mice ......................... 101
 

TABLE A4	 Summary of the Incidence of Nonneoplastic Lesions in Male Mice 

in the 2-Year Gavage Study of AZT .................................... 102
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

92 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE A1 

Summary of the Incidence of Neoplasms in Male Mice in the 2-Year Gavage Study of AZTa 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Disposition Summary 

Animals initially in study 50 50 50 50 

Early deaths 

Accidental deaths 3 

Moribund 6 9 9 4 

Natural deaths 12 6 9 4 

Survivors 

Terminal sacrifice 32 35 29 42 

Animals examined microscopically 50 50 50 50 

Alimentary System 

Esophagus (50) (50) (49) (50) 

Sarcoma, metastatic, skin 1 (2%) 

Gallbladder (41) (42) (46) (44) 

Intestine large, cecum (47) (48) (45) (49) 

Intestine small, duodenum (48) (48) (47) (47) 

Intestine small, jejunum (47) (48) (45) (47) 

Carcinoma 1 (2%) 2 (4%) 1 (2%) 

Intestine small, ileum (47) (48) (45) (47) 

Liver (50) (50) (50) (50) 

Hemangioma 2 (4%) 1 (2%) 1 (2%) 

Hemangiosarcoma 1 (2%) 2 (4%) 3 (6%) 1 (2%) 

Hemangiosarcoma, multiple 5 (10%) 2 (4%) 1 (2%) 2 (4%) 

Hepatoblastoma 1 (2%) 2 (4%) 5 (10%) 2 (4%) 

Hepatoblastoma, multiple 1 (2%) 

Hepatocellular carcinoma 17 (34%) 15 (30%) 15 (30%) 15 (30%) 

Hepatocellular carcinoma, multiple 4 (8%) 11 (22%) 7 (14%) 4 (8%) 

Hepatocellular adenoma 17 (34%) 19 (38%) 14 (28%) 21 (42%) 

Hepatocellular adenoma, multiple 8 (16%) 4 (8%) 9 (18%) 5 (10%) 

Hepatocholangiocarcinoma 1 (2%) 1 (2%) 

Histiocytic sarcoma 1 (2%) 

Sarcoma, metastatic, mesentery 1 (2%) 

Sarcoma, metastatic, skin 1 (2%) 

Mesentery (1) (4) (5) (2) 

Hepatocellular carcinoma, metastatic, liver 1 (20%) 

Sarcoma 1 (20%) 

Pancreas (50) (49) (49) (50) 

Histiocytic sarcoma 1 (2%) 

Sarcoma, metastatic, mesentery 1 (2%) 

Salivary glands (50) (49) (49) (50) 

Hemangioma 1 (2%) 

Histiocytic sarcoma 1 (2%) 

Stomach, forestomach (50) (48) (49) (50) 

Stomach, glandular (50) (48) (49) (50) 

Sarcoma, metastatic, mesentery 1 (2%) 

Cardiovascular System 

Heart (50) (50) (50) (50) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 

Sarcoma, metastatic, skin 1 (2%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 93 

TABLE A1 

Summary of the Incidence of Neoplasms in Male Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Endocrine System 

Adrenal cortex (50) (49) (49) (49) 

Adenoma 1 (2%) 

Hepatocellular carcinoma, metastatic, liver 1 (2%) 

Sarcoma, metastatic, mesentery 1 (2%) 

Capsule, adenoma 5 (10%) 3 (6%) 1 (2%) 2 (4%) 

Adrenal medulla (50) (49) (48) (49) 

Sarcoma, metastatic, mesentery 1 (2%) 

Islets, pancreatic (50) (49) (49) (50) 

Adenoma 1 (2%) 1 (2%) 

Thyroid gland (50) (49) (48) (50) 

Bilateral, follicular cell, adenoma 1 (2%) 

Follicular cell, adenoma 2 (4%) 3 (6%) 2 (4%) 1 (2%) 

General Body System 

Peritoneum (1) 

Hepatocholangiocarcinoma, metastatic, liver 1 (100%) 

Tissue NOS (1) (1) 

Hepatocellular carcinoma, metastatic, liver 1 (100%) 

Genital System 

Epididymis (50) (49) (50) (50) 

Histiocytic sarcoma 1 (2%) 

Preputial gland (48) (50) (50) (49) 

Hemangiosarcoma 1 (2%) 

Prostate (50) (49) (50) (50) 

Seminal vesicle (50) (49) (50) (50) 

Histiocytic sarcoma 1 (2%) 

Sarcoma, metastatic, mesentery 1 (2%) 

Testes (50) (49) (50) (50) 

Histiocytic sarcoma 1 (2%) 

Hematopoietic System 

Bone marrow (50) (50) (49) (50) 

Hemangiosarcoma 1 (2%) 1 (2%) 1 (2%) 

Lymph node (6) (7) (5) (1) 

Mediastinal, sarcoma, metastatic, skin 1 (17%) 

Popliteal, hemangiosarcoma 1 (17%) 

Renal, histiocytic sarcoma 1 (14%) 

Lymph node, mandibular (49) (48) (49) (50) 

Lymph node, mesenteric (48) (49) (49) (49) 

Hemangiosarcoma 1 (2%) 

Spleen (50) (49) (48) (50) 

Hemangioma 1 (2%) 

Hemangiosarcoma 2 (4%) 1 (2%) 

Thymus (41) (44) (41) (35) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

94 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE A1 

Summary of the Incidence of Neoplasms in Male Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Integumentary System 

Skin 

Subcutaneous tissue, chondrosarcoma

Subcutaneous tissue, fibrosarcoma

Subcutaneous tissue, hemangiosarcoma

Subcutaneous tissue, histiocytic sarcoma

Subcutaneous tissue, sarcoma

(50) 

1 (2%) 

1 (2%) 

1 (2%) 

(50) 

1 (2%) 

1 (2%) 

1 (2%) 

(50) 

2 (4%) 

1 (2%) 

(50) 

1 (2%) 

Musculoskeletal System 

Skeletal muscle 

Rhabdomyosarcoma

Sarcoma, metastatic, mesentery

Sarcoma, metastatic, skin

(50) 

1 (2%) 

(50) (50) 

1 (2%) 

(50) 

1 (2%) 

Nervous System 

Brain 

Cranial nerve, schwannoma malignant

(50) (50) (49) 

1 (2%) 

(50) 

Respiratory System 

Lung 

Alveolar/bronchiolar adenoma

Alveolar/bronchiolar adenoma, multiple

Alveolar/bronchiolar carcinoma

Alveolar/bronchiolar carcinoma, multiple

Hepatoblastoma, metastatic, liver

Hepatocellular carcinoma, metastatic, liver

Hepatocholangiocarcinoma, metastatic, liver

Sarcoma, metastatic, skin

Mediastinum, hepatocholangiocarcinoma, 

metastatic, liver

Nose 

Schwannoma malignant, metastatic, brain

(50) 

8 (16%) 

4 (8%) 

4 (8%) 

6 (12%) 

1 (2%) 

(50) 

(50) 

6 (12%) 

1 (2%) 

2 (4%) 

2 (4%) 

(50) 

(50) 

9 (18%) 

2 (4%) 

3 (6%) 

2 (4%) 

4 (8%) 

1 (2%) 

1 (2%) 

(49) 

1 (2%) 

(50) 

8 (16%) 

2 (4%) 

2 (4%) 

3 (6%) 

(50) 

Special Senses System 

Harderian gland

Adenoma

Carcinoma

 (3)

 3 (100%)

 (7)

 2 (29%) 

3 (43%) 

(2) 

2 (100%)

(10) 

10 (100%) 

Urinary System 

Kidney 

Hepatocellular carcinoma, metastatic, liver

Sarcoma, metastatic, skin

Renal tubule, adenoma

Renal tubule, carcinoma

Urinary bladder 

Histiocytic sarcoma

(50) 

1 (2%) 

(50) 

(48) 

(50) 

1 (2%) 

(49) 

1 (2%) 

(50) 

(50) 

3 (6%) 

1 (2%) 

(50) 
 

 

95 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE A1 

Summary of the Incidence of Neoplasms in Male Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Systemic Lesions 

Multiple organsb (50) (50) (50) (50) 

Histiocytic sarcoma 2 (4%) 

Lymphoma malignant 1 (2%) 6 (12%) 7 (14%) 5 (10%) 

Neoplasm Summary 

Total animals with primary neoplasmsc 43 49 45 50 

Total primary neoplasms 90 96 91 88 

Total animals with benign neoplasms 33 31 29 42 

Total benign neoplasms 49 42 42 51 

Total animals with malignant neoplasms 28 40 39 29 

Total malignant neoplasms 41 54 49 37 

Total animals with metastatic neoplasms 6 3 9 3 

Total metastatic neoplasms 13 3 22 3 

a Number of animals examined microscopically at the site and the number of animals with neoplasm b Number of animals with any tissue examined microscopically 

Primary neoplasms: all neoplasms except metastatic neoplasms 
 

96 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE A2 

Statistical Analysis of Primary Neoplasms in Male Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Adrenal Cortex: Adenoma 

Overall ratea 

Adjusted rateb 5/50 (10%) 

14.9% 

4/49 (8%) 

11.8% 

1/49 (2%) 

3.4% 

2/49 (4%) 

4.9% 

Terminal ratec 4/32 (13%) 4/34 (12%) 1/29 (3%) 2/41 (5%) 

First incidence (days) 

Life table testd 

698 

P=0.073N 

729 (T) 

P=0.464N 

729 (T) 

P=0.131N 

729 (T) 

P=0.136N 

Logistic regression testd 

Cochran-Armitage testd 

Fisher exact testd 

P=0.083N 

P=0.118N 

P=0.479N 

P=0.513N 

P=0.126N 

P=0.107N 

P=0.161N 

P=0.226N 

Harderian Gland: Adenoma 

Overall rate 3/50 (6%) 2/50 (4%) 2/50 (4%) 10/50 (20%) 

Adjusted rate 9.4% 5.7% 6.3% 23.1% 

Terminal rate 3/32 (9%) 2/35 (6%) 1/29 (3%) 9/42 (21%) 

First incidence (days) 729 (T) 729 (T) 667 612 

Life table test P=0.016 P=0.459N P=0.546N P=0.096 

Logistic regression test P=0.009 P=0.459N P=0.546N P=0.059 

Cochran-Armitage test P=0.004 

Fisher exact test P=0.500N P=0.500N P=0.036 

Harderian Gland: Carcinoma 

Overall rate 0/50 (0%) 3/50 (6%) 0/50 (0%) 0/50 (0%) 

Adjusted rate 0.0% 7.7% 0.0% 0.0% 

Terminal rate 0/32 (0%) 2/35 (6%) 0/29 (0%) 0/42 (0%) 

First incidence (days) 

Life table test 

—e 

P=0.278N 

458 

P=0.132 

— 

—f — 

— 

Logistic regression test P=0.321N P=0.126 — — 

Cochran-Armitage test P=0.311N 

Fisher exact test P=0.121 — — 

Harderian Gland: Adenoma or Carcinoma 

Overall rate 3/50 (6%) 5/50 (10%) 2/50 (4%) 10/50 (20%) 

Adjusted rate 9.4% 13.3% 6.3% 23.1% 

Terminal rate 3/32 (9%) 4/35 (11%) 1/29 (3%) 9/42 (21%) 

First incidence (days) 729 (T) 458 667 612 

Life table test P=0.055 P=0.399 P=0.546N P=0.096 

Logistic regression test P=0.027 P=0.355 P=0.546N P=0.059 

Cochran-Armitage test P=0.019 

Fisher exact test P=0.357 P=0.500N P=0.036 

Kidney (Renal Tubule): Adenoma 

Overall rate 0/50 (0%) 0/48 (0%) 0/49 (0%) 3/50 (6%) 

Adjusted rate 0.0% 0.0% 0.0% 7.1% 

Terminal rate 0/32 (0%) 0/35 (0%) 0/29 (0%) 3/42 (7%) 

First incidence (days) — — — 729 (T) 

Life table test P=0.022 — — P=0.173 

Logistic regression test P=0.022 — — P=0.173 

Cochran-Armitage test P=0.013 

Fisher exact test — — P=0.121 
 

AZT and AZT/"-Interferon A/D, NTP TR 469 97 

TABLE A2 

Statistical Analysis of Primary Neoplasms in Male Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Kidney (Renal Tubule): Adenoma or Carcinoma 

Overall rate 0/50 (0%) 0/48 (0%) 0/49 (0%) 4/50 (8%) 

Adjusted rate 0.0% 0.0% 0.0% 9.5% 

Terminal rate 0/32 (0%) 0/35 (0%) 0/29 (0%) 4/42 (10%) 

First incidence (days) — — — 729 (T) 

Life table test P=0.007 — — P=0.103 

Logistic regression test P=0.007 — — P=0.103 

Cochran-Armitage test P=0.003 

Fisher exact test — — P=0.059 

Liver: Hemangiosarcoma 

Overall rate 6/50 (12%) 4/50 (8%) 4/50 (8%) 3/50 (6%) 

Adjusted rate 13.5% 11.0% 12.8% 6.4% 

Terminal rate 0/32 (0%) 3/35 (9%) 3/29 (10%) 1/42 (2%) 

First incidence (days) 570 711 639 513 

Life table test P=0.160N P=0.350N P=0.440N P=0.209N 

Logistic regression test P=0.301N P=0.359N P=0.435N P=0.536N 

Cochran-Armitage test P=0.208N 

Fisher exact test P=0.370N P=0.370N P=0.243N 

Liver: Hepatocellular Adenoma 

Overall rate 25/50 (50%) 23/50 (46%) 23/50 (46%) 26/50 (52%) 

Adjusted rate 65.2% 58.3% 66.8% 57.5% 

Terminal rate 19/32 (59%) 19/35 (54%) 18/29 (62%) 23/42 (55%) 

First incidence (days) 576 458 473 540 

Life table test P=0.239N P=0.292N P=0.550 P=0.215N 

Logistic regression test P=0.537N P=0.422N P=0.574 P=0.528N 

Cochran-Armitage test P=0.415 

Fisher exact test P=0.421N P=0.421N P=0.500 

Liver: Hepatocellular Carcinoma 

Overall rate 21/50 (42%) 26/50 (52%) 22/50 (44%) 19/50 (38%) 

Adjusted rate 46.1% 61.6% 57.0% 40.4% 

Terminal rate 8/32 (25%) 19/35 (54%) 13/29 (45%) 14/42 (33%) 

First incidence (days) 425 350 505 584 

Life table test P=0.091N P=0.345 P=0.358 P=0.192N 

Logistic regression test P=0.256N P=0.211 P=0.422 P=0.521N 

Cochran-Armitage test P=0.250N 

Fisher exact test P=0.212 P=0.500 P=0.419N 

Liver: Hepatocellular Adenoma or Carcinoma 

Overall rate 36/50 (72%) 39/50 (78%) 34/50 (68%) 39/50 (78%) 

Adjusted rate 76.5% 88.5% 84.7% 79.6% 

Terminal rate 21/32 (66%) 30/35 (86%) 23/29 (79%) 32/42 (76%) 

First incidence (days) 425 350 473 540 

Life table test P=0.160N P=0.543 P=0.469 P=0.236N 

Logistic regression test P=0.487 P=0.301 P=0.580N P=0.341 

Cochran-Armitage test P=0.372 

Fisher exact test P=0.322 P=0.414N P=0.322 
98 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE A2 

Statistical Analysis of Primary Neoplasms in Male Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Liver: Hepatoblastoma 

Overall rate 1/50 (2%) 2/50 (4%) 6/50 (12%) 2/50 (4%)
 

Adjusted rate 3.1% 5.7% 18.1% 4.8%
 

Terminal rate 1/32 (3%) 2/35 (6%) 3/29 (10%) 2/42 (5%)
 

First incidence (days) 729 (T) 729 (T) 638 729 (T)
 

Life table test P=0.472 P=0.531 P=0.048 P=0.595 

Logistic regression test P=0.407 P=0.531 P=0.044 P=0.595 

Cochran-Armitage test P=0.357
 

Fisher exact test P=0.500 P=0.056 P=0.500 

Liver: Hepatocellular Carcinoma or Hepatoblastoma 

Overall rate 21/50 (42%) 27/50 (54%) 26/50 (52%) 19/50 (38%) 

Adjusted rate 46.1% 64.0% 64.6% 40.4% 

Terminal rate 8/32 (25%) 20/35 (57%) 15/29 (52%) 14/42 (33%) 

First incidence (days) 425 350 505 584 

Life table test P=0.091N P=0.289 P=0.153 P=0.192N 

Logistic regression test P=0.260N P=0.157 P=0.140 P=0.521N 

Cochran-Armitage test P=0.259N 

Fisher exact test P=0.158 P=0.212 P=0.419N 

Liver: Hepatocellular Adenoma, Hepatocellular Carcinoma, or Hepatoblastoma 

Overall rate 36/50 (72%) 39/50 (78%) 36/50 (72%) 39/50 (78%) 

Adjusted rate 76.5% 88.5% 87.6% 79.6% 

Terminal rate 21/32 (66%) 30/35 (86%) 24/29 (83%) 32/42 (76%) 

First incidence (days) 425 350 473 540 

Life table test P=0.165N P=0.543 P=0.341 P=0.236N 

Logistic regression test P=0.468 P=0.301 P=0.404 P=0.341 

Cochran-Armitage test P=0.350 

Fisher exact test P=0.322 P=0.588N P=0.322 

Lung: Alveolar/bronchiolar Adenoma 

Overall rate 12/50 (24%) 7/50 (14%) 11/50 (22%) 8/50 (16%) 

Adjusted rate 33.2% 19.1% 32.8% 18.6% 

Terminal rate 9/32 (28%) 6/35 (17%) 7/29 (24%) 7/42 (17%) 

First incidence (days) 565 624 584 694 

Life table test P=0.146N P=0.118N P=0.572 P=0.093N 

Logistic regression test P=0.228N P=0.150N P=0.592N P=0.172N 

Cochran-Armitage test P=0.292N 

Fisher exact test P=0.154N P=0.500N P=0.227N 

Lung: Alveolar/bronchiolar Carcinoma 

Overall rate 4/50 (8%) 2/50 (4%) 3/50 (6%) 4/50 (8%) 

Adjusted rate 11.2% 5.7% 10.3% 9.3% 

Terminal rate 2/32 (6%) 2/35 (6%) 3/29 (10%) 3/42 (7%) 

First incidence (days) 596 729 (T) 729 (T) 695 

Life table test P=0.545N P=0.304N P=0.550N P=0.514N 

Logistic regression test P=0.536 P=0.335N P=0.550N P=0.616N 

Cochran-Armitage test P=0.481 

Fisher exact test P=0.339N P=0.500N P=0.643N 
AZT and AZT/"-Interferon A/D, NTP TR 469 99 

TABLE A2 

Statistical Analysis of Primary Neoplasms in Male Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Lung: Alveolar/bronchiolar Adenoma or Carcinoma 

Overall rate 14/50 (28%) 9/50 (18%) 14/50 (28%) 11/50 (22%) 

Adjusted rate 38.0% 24.7% 41.9% 25.0% 

Terminal rate 10/32 (31%) 8/35 (23%) 10/29 (34%) 9/42 (21%) 

First incidence (days) 565 624 584 694 

Life table test P=0.201N P=0.127N P=0.462 P=0.134N 

Logistic regression test P=0.312N P=0.163N P=0.476 P=0.238N 

Cochran-Armitage test P=0.411N 

Fisher exact test P=0.171N P=0.588N P=0.322N 

Skin (Subcutaneous Tissue): Fibrosarcoma or Sarcoma 

Overall rate 2/50 (4%) 1/50 (2%) 3/50 (6%) 1/50 (2%) 

Adjusted rate 5.0% 2.2% 8.3% 2.4% 

Terminal rate 0/32 (0%) 0/35 (0%) 1/29 (3%) 1/42 (2%) 

First incidence (days) 325 568 422 729 (T) 

Life table test P=0.425N P=0.492N P=0.465 P=0.441N 

Logistic regression test P=0.524N P=0.421N P=0.616 P=0.695N 

Cochran-Armitage test P=0.474N 

Fisher exact test P=0.500N P=0.500 P=0.500N 

Thyroid Gland (Follicular Cell): Adenoma 

Overall rate 2/50 (4%) 4/49 (8%) 2/48 (4%) 1/50 (2%) 

Adjusted rate 5.5% 11.4% 6.5% 2.4% 

Terminal rate 1/32 (3%) 4/35 (11%) 1/29 (3%) 1/42 (2%) 

First incidence (days) 638 729 (T) 691 729 (T) 

Life table test P=0.196N P=0.374 P=0.657 P=0.424N 

Logistic regression test P=0.233N P=0.337 P=0.661 P=0.496N 

Cochran-Armitage test P=0.263N 

Fisher exact test P=0.329 P=0.676 P=0.500N 

All Organs: Hemangiosarcoma 

Overall rate 7/50 (14%) 6/50 (12%) 4/50 (8%) 3/50 (6%) 

Adjusted rate 16.2% 16.1% 12.8% 6.4% 

Terminal rate 1/32 (3%) 4/35 (11%) 3/29 (10%) 1/42 (2%) 

First incidence (days) 570 711 639 513 

Life table test P=0.072N P=0.460N P=0.332N P=0.129N 

Logistic regression test P=0.146N P=0.497N P=0.250N P=0.357N 

Cochran-Armitage test P=0.101N 

Fisher exact test P=0.500N P=0.262N P=0.159N 

All Organs: Hemangioma or Hemangiosarcoma 

Overall rate 9/50 (18%) 6/50 (12%) 6/50 (12%) 4/50 (8%) 

Adjusted rate 21.6% 16.1% 19.5% 8.7% 

Terminal rate 3/32 (9%) 4/35 (11%) 5/29 (17%) 2/42 (5%) 

First incidence (days) 570 711 639 513 

Life table test P=0.064N P=0.259N P=0.372N P=0.081N 

Logistic regression test P=0.101N P=0.288N P=0.307N P=0.239N 

Cochran-Armitage test P=0.103N 

Fisher exact test P=0.288N P=0.288N P=0.117N 
100 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE A2 

Statistical Analysis of Primary Neoplasms in Male Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

All Organs: Malignant Lymphoma 

Overall rate 1/50 (2%) 6/50 (12%) 7/50 (14%) 5/50 (10%) 

Adjusted rate 2.5% 13.3% 22.0% 11.5% 

Terminal rate 0/32 (0%) 1/35 (3%) 5/29 (17%) 4/42 (10%) 

First incidence (days) 638 257 596 612 

Life table test P=0.277 P=0.070 P=0.027 P=0.164 

Logistic regression test P=0.141 P=0.073 P=0.025 P=0.097 

Cochran-Armitage test P=0.174 

Fisher exact test P=0.056 P=0.030 P=0.102 

All Organs: Benign Neoplasms 

Overall rate 33/50 (66%) 31/50 (62%) 29/50 (58%) 42/50 (84%) 

Adjusted rate 78.2% 77.1% 78.0% 89.3% 

Terminal rate 23/32 (72%) 26/35 (74%) 21/29 (72%) 37/42 (88%) 

First incidence (days) 565 458 473 540 

Life table test P=0.392 P=0.264N P=0.507N P=0.566 

Logistic regression test P=0.048 P=0.431N P=0.464N P=0.075 

Cochran-Armitage test P=0.022 

Fisher exact test P=0.418N P=0.268N P=0.032 

All Organs: Malignant Neoplasms 

Overall rate 28/50 (56%) 40/50 (80%) 39/50 (78%) 29/50 (58%) 

Adjusted rate 58.0% 80.0% 84.8% 60.4% 

Terminal rate 12/32 (38%) 25/35 (71%) 22/29 (76%) 23/42 (55%) 

First incidence (days) 325 257 422 513 

Life table test P=0.109N P=0.098 P=0.028 P=0.270N 

Logistic regression test P=0.512N P=0.004 P=0.006 P=0.335 

Cochran-Armitage test P=0.379N 

Fisher exact test P=0.009 P=0.016 P=0.500 

All Organs: Benign or Malignant Neoplasms 

Overall rate 43/50 (86%) 49/50 (98%) 45/50 (90%) 50/50 (100%) 

Adjusted rate 86.0% 98.0% 97.8% 100.0% 

Terminal rate 25/32 (78%) 34/35 (97%) 28/29 (97%) 42/42 (100%) 

First incidence (days) 325 257 422 513 

Life table test P=0.244N P=0.379 P=0.206 P=0.341N 

Logistic regression test P=0.010 P=0.022 P=0.151 P=0.003 

Cochran-Armitage test P=0.019 

Fisher exact test P=0.030 P=0.380 P=0.006 

(T)Terminal sacrifice 

a Number of neoplasm-bearing animals/number of animals examined. Denominator is number of animals examined microscopically for adrenal gland, kidney, 

liver, lung, and thyroid gland; for other tissues, denominator is number of animals necropsied. b Kaplan-Meier estimated neoplasm incidence at the end of the study after adjustment for intercurrent mortality 

Observed incidence at terminal kill 

d	 Beneath the vehicle control incidence are the P values associated with the trend test. Beneath the dosed group incidence are the P values corresponding to 

pairwise comparisons between the vehicle controls and that dosed group. The life table test regards neoplasms in animals dying prior to terminal kill as being 

(directly or indirectly) the cause of death. The logistic regression test regards these lesions as nonfatal. The Cochran-Armitage and Fisher exact tests compare 

directly the overall incidence rates. For all tests, a negative trend or a lower incidence in a dose group is indicated by N. e Not applicable; no neoplasms in animal group f Value of statistic cannot be computed. 
AZT and AZT/"-Interferon A/D, NTP TR 469 101 

TABLE A3a 

Historical Incidence of Renal Tubule Neoplasms in Water Gavage Vehicle Control Male B6C3F a 1 Mice

Incidence in Controls 

Adenoma Carcinoma Adenoma 

or Carcinoma 

Overall Historical Incidence 

Total 

Standard deviation 

Range 

0/365 2/365 (0.6%) 

1.5% 

0%-4% 

2/365 (0.6%) 

1.5% 

0%-4% 

a Data as of 12 May 1995 

TABLE A3b 

Historical Incidence of Harderian Gland Neoplasms in Water Gavage Vehicle Control Male B6C3F a 1 Mice

Incidence in Controls 

Adenoma Carcinoma Adenoma 

or Carcinoma 

Overall Historical Incidence 

Total 18/365 (4.9%) 1/365 (0.3%) 19/365 (5.2%) 

Standard deviation 3.5% 0.8% 3.3% 

Range 2%-10% 0%-2% 2%-10% 

a Data as of 12 May 1995 

TABLE A3c 

Historical Incidence of Liver Neoplasms in Water Gavage Vehicle Control Male B6C3F a 1 Mice

Incidence in Controls 

Hepatocellular Hepatocellular Hepatoblastoma Hepatocellular Adenoma, 

Adenoma Carcinoma Hepatocellular Carcinoma, 

or Hepatoblastoma 

Overall Historical Incidence 

Total 

Standard deviation 

Range 

66/365 (18.1%) 

15.6% 

4%-52% 

45/365 (12.3%) 

5.6% 

6%-24% 

0/365 104/365 (28.5%) 

15.4% 

14%-60% 

a Data as of 12 May 1995 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

102 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE A4 

Summary of the Incidence of Nonneoplastic Lesions in Male Mice in the 2-Year Gavage Study of AZTa 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Disposition Summary 

Animals initially in study 50 50 50 50 

Early deaths 

Accidental deaths 3 

Moribund 6 9 9 4 

Natural deaths 12 6 9 4 

Survivors 

Terminal sacrifice 32 35 29 42 

Animals examined microscopically 50 50 50 50 

Alimentary System 

Esophagus (50) (50) (49) (50) 

Necrosis 1 (2%) 

Muscularis, inflammation, chronic 1 (2%) 

Gallbladder (41) (42) (46) (44) 

Cyst 1 (2%) 

Intestine large, cecum (47) (48) (45) (49) 

Hyperplasia, lymphoid 1 (2%) 

Intestine small, duodenum (48) (48) (47) (47) 

Cyst 1 (2%) 

Inflammation, chronic, focal 1 (2%) 

Intestine small, jejunum (47) (48) (45) (47) 

Hyperplasia, adenomatous 1 (2%) 

Intestine small, ileum (47) (48) (45) (47) 

Peyer’s patch, hyperplasia, lymphoid 1 (2%) 1 (2%) 

Liver (50) (50) (50) (50) 

Angiectasis 3 (6%) 1 (2%) 

Basophilic focus 5 (10%) 1 (2%) 3 (6%) 3 (6%) 

Clear cell focus 4 (8%) 3 (6%) 4 (8%) 

Eosinophilic focus 12 (24%) 12 (24%) 7 (14%) 12 (24%) 

Inflammation, chronic 17 (34%) 24 (48%) 24 (48%) 16 (32%) 

Mixed cell focus 2 (4%) 4 (8%) 7 (14%) 4 (8%) 

Necrosis, focal 8 (16%) 8 (16%) 9 (18%) 3 (6%) 

Vacuolization cytoplasmic 3 (6%) 1 (2%) 4 (8%) 3 (6%) 

Bile duct, cyst 1 (2%) 1 (2%) 

Bile duct, hyperplasia 1 (2%) 9 (18%) 4 (8%) 3 (6%) 

Hepatocyte, karyomegaly 7 (14%) 10 (20%) 15 (30%) 5 (10%) 

Mesentery (1) (4) (5) (2) 

Hemorrhage 1 (20%) 

Inflammation, chronic 1 (20%) 

Inflammation, granulomatous 1 (100%) 

Thrombosis 1 (25%) 

Artery, inflammation, chronic 1 (25%) 

Fat, necrosis 2 (50%) 2 (40%) 2 (100%) 

Pancreas (50) (49) (49) (50) 

Atrophy 1 (2%) 3 (6%) 3 (6%) 

Inflammation, granulomatous 1 (2%) 

Necrosis 1 (2%) 

Thrombosis 1 (2%) 

Artery, inflammation, chronic 1 (2%) 

Duct, cyst 1 (2%) 1 (2%) 

a Number of animals examined microscopically at the site and the number of animals with lesion 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 103 

TABLE A4 

Summary of the Incidence of Nonneoplastic Lesions in Male Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Alimentary System (continued) 

Stomach, forestomach (50) (48) (49) (50) 

Erosion 1 (2%) 1 (2%) 1 (2%) 

Inflammation, chronic 2 (4%) 1 (2%) 

Ulcer 2 (4%) 1 (2%) 

Epithelium, hyperplasia 7 (14%) 4 (8%) 3 (6%) 1 (2%) 

Stomach, glandular (50) (48) (49) (50) 

Erosion 1 (2%) 4 (8%) 

Mineralization 1 (2%) 1 (2%) 2 (4%) 2 (4%) 

Pigmentation, focal 1 (2%) 

Glands, degeneration, cystic, focal 2 (4%) 1 (2%) 2 (4%) 

Tooth (2) (2) (7) (1) 

Developmental malformation 2 (100%) 2 (100%) 7 (100%) 1 (100%) 

Cardiovascular System 

Blood vessel (50) (48) (50) (50) 

Inflammation, chronic 1 (2%) 2 (4%) 

Heart (50) (50) (50) (50) 

Fibrosis 1 (2%) 

Inflammation, chronic, focal 2 (4%) 4 (8%) 1 (2%) 

Mineralization 1 (2%) 

Thrombosis 1 (2%) 2 (4%) 1 (2%) 

Artery, inflammation, chronic 1 (2%) 

Endocrine System 

Adrenal cortex (50) (49) (49) (49) 

Accessory adrenal cortical nodule 1 (2%) 1 (2%) 

Cyst 1 (2%) 1 (2%) 

Cytoplasmic alteration, focal 5 (10%) 11 (22%) 8 (16%) 18 (37%) 

Hyperplasia, focal 3 (6%) 1 (2%) 3 (6%) 5 (10%) 

Hypertrophy, focal 10 (20%) 17 (35%) 8 (16%) 7 (14%) 

Inflammation, chronic, focal 1 (2%) 

Capsule, hyperplasia, focal 3 (6%) 2 (4%) 1 (2%) 

Adrenal medulla (50) (49) (48) (49) 

Hyperplasia 1 (2%) 1 (2%) 

Parathyroid gland (46) (45) (45) (49) 

Cyst 1 (2%) 1 (2%) 1 (2%) 

Pituitary gland (40) (46) (42) (47) 

Pars distalis, cyst 1 (3%) 2 (4%) 1 (2%) 3 (6%) 

Pars distalis, cytoplasmic alteration, focal 1 (2%) 

Pars distalis, hyperplasia, focal 1 (2%) 

Thyroid gland (50) (49) (48) (50) 

Degeneration, cystic, focal 15 (30%) 18 (37%) 11 (23%) 16 (32%) 

Follicle, cyst 8 (16%) 4 (8%) 2 (4%) 5 (10%) 

Follicular cell, hyperplasia 8 (16%) 10 (20%) 11 (23%) 9 (18%) 

General Body System 

None 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

104 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE A4 

Summary of the Incidence of Nonneoplastic Lesions in Male Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Genital System 

Epididymis (50) (49) (50) (50) 

Granuloma sperm 1 (2%) 

Spermatocele 1 (2%) 1 (2%) 

Preputial gland (48) (50) (50) (49) 

Degeneration, cystic 39 (81%) 46 (92%) 44 (88%) 45 (92%) 

Inflammation, chronic 4 (8%) 5 (10%) 2 (4%) 

Prostate (50) (49) (50) (50) 

Inflammation, chronic 3 (6%) 

Inflammation, chronic, focal 3 (6%) 2 (4%) 

Epithelium, hyperplasia, focal 2 (4%) 1 (2%) 

Seminal vesicle (50) (49) (50) (50) 

Angiectasis 1 (2%) 1 (2%) 4 (8%) 

Congestion 1 (2%) 

Inflammation, chronic 1 (2%) 1 (2%) 

Testes (50) (49) (50) (50) 

Germinal epithelium, degeneration 1 (2%) 1 (2%) 1 (2%) 

Hematopoietic System 

Bone marrow (50) (50) (49) (50) 

Angiectasis 1 (2%) 1 (2%) 1 (2%) 

Hyperplasia 2 (4%) 6 (12%) 6 (12%) 1 (2%) 

Lymph node (6) (7) (5) (1) 

Inguinal, hyperplasia, lymphoid 1 (20%) 

Inguinal, pigmentation 1 (17%) 2 (29%) 1 (20%) 

Mediastinal, hyperplasia, lymphoid 1 (17%) 1 (20%) 

Mediastinal, inflammation, granulomatous 1 (17%) 

Pancreatic, hyperplasia, lymphoid 1 (17%) 

Lymph node, mandibular (49) (48) (49) (50) 

Hemorrhage 1 (2%) 

Hyperplasia, histiocytic 1 (2%) 

Hyperplasia, lymphoid 1 (2%) 1 (2%) 1 (2%) 

Infiltration cellular, mast cell 1 (2%) 

Lymph node, mesenteric (48) (49) (49) (49) 

Ectasia 5 (10%) 4 (8%) 1 (2%) 3 (6%) 

Fibrosis 1 (2%) 

Hemorrhage 20 (42%) 31 (63%) 21 (43%) 25 (51%) 

Hyperplasia, lymphoid 3 (6%) 3 (6%) 3 (6%) 4 (8%) 

Inflammation, granulomatous 1 (2%) 

Spleen (50) (49) (48) (50) 

Angiectasis 1 (2%) 

Depletion cellular 1 (2%) 1 (2%) 6 (12%) 

Hematopoietic cell proliferation 18 (36%) 16 (33%) 14 (29%) 11 (22%) 

Hyperplasia, lymphoid 2 (4%) 1 (2%) 2 (4%) 2 (4%) 

Necrosis, focal 1 (2%) 

Thymus (41) (44) (41) (35) 

Cyst 6 (15%) 11 (25%) 5 (12%) 4 (11%) 

Mineralization 1 (2%) 

Necrosis 1 (2%) 

Integumentary System 

Mammary gland (15) (10) (15) (5) 

Inflammation, chronic 1 (10%) 

Skin (50) (50) (50) (50) 

Subcutaneous tissue, edema 1 (2%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 105 

TABLE A4 

Summary of the Incidence of Nonneoplastic Lesions in Male Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Musculoskeletal System 

Bone (50) (50) (50) (50) 

Hyperostosis 30 (60%) 36 (72%) 28 (56%) 41 (82%) 

Skeletal muscle (50) (50) (50) (50) 

Necrosis 1 (2%) 

Nervous System 

Brain (50) (50) (49) (50) 

Hemorrhage 1 (2%) 

Spinal cord (1) (1) 

Degeneration 1 (100%) 

Hemorrhage, focal 1 (100%) 

Respiratory System 

Lung (50) (50) (50) (50) 

Hemorrhage 2 (4%) 1 (2%) 2 (4%) 3 (6%) 

Hyperplasia, histiocytic 2 (4%) 2 (4%) 1 (2%) 

Hyperplasia, lymphoid 1 (2%) 

Infiltration cellular, mixed cell 1 (2%) 1 (2%) 1 (2%) 

Inflammation, chronic 1 (2%) 1 (2%) 1 (2%) 

Alveolar epithelium, hyperplasia 6 (12%) 3 (6%) 1 (2%) 8 (16%) 

Nose (50) (50) (49) (50) 

Nasolacrimal duct, inflammation, suppurative 1 (2%) 

Special Senses System 

Eye (1) 

Cornea, inflammation, chronic 1 (100%) 

Harderian gland (3) (7) (2) (10) 

Hyperplasia, focal 1 (14%) 

Urinary System 

Kidney (50) (48) (49) (50) 

Cyst 2 (4%) 1 (2%) 

Infarct 1 (2%) 2 (4%) 1 (2%) 2 (4%) 

Metaplasia, focal, osseous 1 (2%) 3 (6%) 1 (2%) 

Nephropathy 45 (90%) 44 (92%) 44 (90%) 49 (98%) 

Thrombosis 1 (2%) 

Papilla, necrosis 1 (2%) 

Pelvis, dilatation 1 (2%) 

Renal tubule, accumulation, hyaline droplet 1 (2%) 

Renal tubule, dilatation 1 (2%) 1 (2%) 

Renal tubule, hyperplasia, focal 1 (2%) 

Renal tubule, pigmentation 2 (4%) 1 (2%) 1 (2%) 

Urethra (1) (1) (1) 

Inflammation, chronic 1 (100%) 1 (100%) 1 (100%) 

Urinary bladder (50) (50) (50) (50) 

Hemorrhage 1 (2%) 
106 AZT and AZT/"-Interferon A/D, NTP TR 469 
107 

APPENDIX B
 

SUMMARY OF LESIONS IN FEMALE MICE
 

IN THE 2-YEAR GAVAGE STUDY
 

OF AZT
 

TABLE B1	 Summary of the Incidence of Neoplasms in Female Mice 

in the 2-Year Gavage Study of AZT .................................... 108
 

TABLE B2 Statistical Analysis of Primary Neoplasms in Female Mice 

in the 2-Year Gavage Study of AZT .................................... 112
 

TABLE B3 Historical Incidence of Liver Neoplasms 

in Water Gavage Vehicle Control Female B6C3F Mice 1 ....................... 117
 

TABLE B4	 Summary of the Incidence of Nonneoplastic Lesions in Female Mice 

in the 2-Year Gavage Study of AZT .................................... 118
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

108 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE B1 

Summary of the Incidence of Neoplasms in Female Mice in the 2-Year Gavage Study of AZTa 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Disposition Summary 

Animals initially in study 50 50 50 50 

Early deaths 

Accidental deaths 3 1 

Moribund 5 5 9 7 

Natural deaths 11 6 7 11 

Survivors 

Died last week of study 1 

Terminal sacrifice 34 38 31 31 

Animals examined microscopically 50 50 50 50 

Alimentary System 

Gallbladder (48) (44) (49) (45) 

Intestine large, rectum (46) (48) (46) (45) 

Squamous cell carcinoma, metastatic, vagina 1 (2%) 

Intestine small, jejunum (46) (46) (44) (42) 

Intestine small, ileum (46) (44) (45) (42) 

Liver (50) (50) (50) (50) 

Hemangioma 1 (2%) 

Hemangiosarcoma 2 (4%) 

Hepatoblastoma 1 (2%) 2 (4%) 

Hepatocellular carcinoma 10 (20%) 14 (28%) 10 (20%) 11 (22%) 

Hepatocellular carcinoma, multiple 2 (4%) 3 (6%) 1 (2%) 4 (8%) 

Hepatocellular adenoma 14 (28%) 11 (22%) 9 (18%) 19 (38%) 

Hepatocellular adenoma, multiple 6 (12%) 7 (14%) 8 (16%) 9 (18%) 

Histiocytic sarcoma 2 (4%) 1 (2%) 1 (2%) 1 (2%) 

Mesentery (13) (17) (8) (11) 

Carcinoma, metastatic, pancreas 1 (8%) 

Carcinoma, metastatic, uterus 1 (6%) 

Fibrosarcoma, metastatic, skeletal muscle 1 (8%) 

Histiocytic sarcoma 1 (6%) 1 (13%) 

Sarcoma 2 (15%) 

Sarcoma, metastatic, pancreas 1 (9%) 

Pancreas (50) (49) (49) (48) 

Carcinoma 1 (2%) 

Carcinoma, metastatic, uterus 1 (2%) 

Histiocytic sarcoma 1 (2%) 

Sarcoma 1 (2%) 

Salivary glands (50) (50) (50) (50) 

Stomach, forestomach (49) (49) (49) (49) 

Histiocytic sarcoma 1 (2%) 

Squamous cell carcinoma 1 (2%) 

Squamous cell papilloma 3 (6%) 3 (6%) 1 (2%) 1 (2%) 

Stomach, glandular (49) (49) (48) (49) 

Histiocytic sarcoma 1 (2%) 

Sarcoma, metastatic, pancreas 1 (2%) 

Tongue (1) 

Squamous cell papilloma 1 (100%) 

Cardiovascular System 

Heart (49) (50) (50) (50) 

Carcinoma, metastatic, uterus 1 (2%) 

Histiocytic sarcoma 1 (2%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 109 

TABLE B1 

Summary of the Incidence of Neoplasms in Female Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Endocrine System 

Adrenal cortex (50) (49) (50) (50) 

Histiocytic sarcoma 1 (2%) 

Capsule, carcinoma, metastatic, uterus 1 (2%) 

Capsule, fibrosarcoma, metastatic, skeletal

 muscle 1 (2%) 

Islets, pancreatic (49) (49) (50) (47) 

Adenoma 2 (4%) 1 (2%) 1 (2%) 

Pituitary gland (46) (49) (46) (46) 

Pars distalis, adenoma 2 (4%) 5 (10%) 1 (2%) 

Thyroid gland (49) (50) (50) (50) 

Follicular cell, adenoma 3 (6%) 2 (4%) 4 (8%) 

Follicular cell, carcinoma 1 (2%) 1 (2%) 

General Body System 

Peritoneum (1) 

Tissue NOS (1) 

Genital System 

Clitoral gland (49) (49) (49) (48) 

Carcinoma 1 (2%) 

Ovary (50) (50) (47) (48) 

Cystadenoma 2 (4%) 2 (4%) 3 (6%) 

Granulosa cell tumor benign 2 (4%) 

Hemangioma 1 (2%) 

Histiocytic sarcoma 1 (2%) 1 (2%) 

Teratoma benign 1 (2%) 

Uterus (50) (50) (49) (50) 

Histiocytic sarcoma 1 (2%) 1 (2%) 1 (2%) 1 (2%) 

Leiomyosarcoma 1 (2%) 

Endometrium, carcinoma 1 (2%) 1 (2%) 

Endometrium, polyp stromal 1 (2%) 2 (4%) 

Endometrium, sarcoma stromal 1 (2%) 

Vagina (50) (49) (45) (49) 

Histiocytic sarcoma 1 (2%) 

Squamous cell carcinoma 5 (11%) 9 (18%) 

Squamous cell papilloma 2 (4%) 

Hematopoietic System 

Bone marrow (50) (49) (50) (50) 

Hemangiosarcoma 1 (2%) 

Histiocytic sarcoma 1 (2%) 

Lymph node (7) (5) (7) (10) 

Fibrosarcoma, metastatic, skin 1 (10%) 

Iliac, histiocytic sarcoma 1 (20%) 

Inguinal, carcinoma, metastatic, clitoral

 gland 1 (10%) 

Inguinal, histiocytic sarcoma 1 (20%) 

Mediastinal, histiocytic sarcoma 1 (14%) 

Renal, carcinoma, metastatic, clitoral gland 1 (10%) 

Renal, histiocytic sarcoma 1 (14%) 

Lymph node, mandibular (50) (46) (48) (48) 

Histiocytic sarcoma 1 (2%) 1 (2%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

110 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE B1 

Summary of the Incidence of Neoplasms in Female Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Hematopoietic System (continued) 

Lymph node, mesenteric (50) (47) (48) (47) 

Histiocytic sarcoma 1 (2%) 1 (2%) 1 (2%) 

Spleen (49) (48) (49) (50) 

Hemangiosarcoma 1 (2%) 1 (2%) 

Sarcoma, metastatic, pancreas 1 (2%) 

Thymus (48) (46) (49) (46) 

Carcinoma, metastatic, uterus 1 (2%) 

Histiocytic sarcoma 1 (2%) 

Integumentary System 

Skin (50) (49) (50) (50) 

Trichoepithelioma 1 (2%) 

Pinna, squamous cell carcinoma 1 (2%) 

Subcutaneous tissue, fibrosarcoma 1 (2%) 2 (4%) 2 (4%) 

Subcutaneous tissue, histiocytic sarcoma 1 (2%) 

Musculoskeletal System 

Bone (50) (50) (50) (50) 

Carcinoma, metastatic, uterus 1 (2%) 

Skeletal muscle (50) (50) (50) (50) 

Carcinoma, metastatic, uterus 1 (2%) 

Fibrosarcoma 1 (2%) 

Hemangiosarcoma 1 (2%) 

Sarcoma 1 (2%) 

Sarcoma, metastatic, pancreas 1 (2%) 

Nervous System 

Brain (50) (50) (50) (50) 

Respiratory System 

Lung (49) (50) (50) (50) 

Alveolar/bronchiolar adenoma 3 (6%) 3 (6%) 2 (4%) 7 (14%) 

Alveolar/bronchiolar carcinoma 3 (6%) 5 (10%) 4 (8%) 

Carcinoma, metastatic, clitoral gland 1 (2%) 

Carcinoma, metastatic, harderian gland 1 (2%) 1 (2%) 

Carcinoma, metastatic, pancreas 1 (2%) 

Carcinoma, metastatic, uterus 1 (2%) 

Fibrosarcoma, metastatic, skin 2 (4%) 

Hepatocellular carcinoma, metastatic, liver 3 (6%) 4 (8%) 1 (2%) 2 (4%) 

Histiocytic sarcoma 1 (2%) 1 (2%) 

Leiomyosarcoma, metastatic, uterus 1 (2%) 

Squamous cell carcinoma, metastatic, vagina 1 (2%) 

Nose (50) (50) (50) (50) 

Special Senses System 

Harderian gland (5) (2) (2) (2) 

Adenoma 4 (80%) 2 (100%) 1 (50%) 

Carcinoma 1 (20%) 1 (50%) 1 (50%) 
 

 

 

 

 

 

 

111 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE B1 

Summary of the Incidence of Neoplasms in Female Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Urinary System 

Kidney (50) (50) (50) (50) 

Histiocytic sarcoma 1 (2%) 1 (2%) 

Urethra (1) 

Squamous cell carcinoma, metastatic, vagina 1 (100%) 

Urinary bladder (50) (50) (49) (49) 

Hemangioma 1 (2%) 

Hemangiosarcoma 1 (2%) 

Systemic Lesions 

Multiple organsb (50) (50) (50) (50) 

Histiocytic sarcoma 2 (4%) 1 (2%) 3 (6%) 1 (2%) 

Lymphoma malignant 5 (10%) 10 (20%) 7 (14%) 9 (18%) 

Mesothelioma malignant 1 (2%) 

Neoplasm Summary 

Total animals with primary neoplasmsc 41 42 41 43 

Total primary neoplasms 70 79 66 92 

Total animals with benign neoplasms 30 33 26 31 

Total benign neoplasms 40 41 31 42 

Total animals with malignant neoplasms 26 30 28 35 

Total malignant neoplasms 30 38 35 50 

Total animals with metastatic neoplasms 5 4 3 9 

Total metastatic neoplasms 8 12 3 15 

a Number of animals examined microscopically at the site and the number of animals with neoplasm b Number of animals with any tissue examined microscopically 

Primary neoplasms: all neoplasms except metastatic neoplasms 
112 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE B2 

Statistical Analysis of Primary Neoplasms in Female Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Harderian Gland: Adenoma 

Overall ratea 

Adjusted rateb 4/50 (8%) 

11.8% 

2/50 (4%) 

5.1% 

0/50 (0%) 

0.0% 

1/50 (2%) 

3.2% 

Terminal ratec 4/34 (12%) 2/39 (5%) 0/31 (0%) 1/31 (3%) 

First incidence (days) 

Life table testd 731 (T) 

P=0.107N 

731 (T) 

P=0.275N 

—e 

P=0.074N 

731 (T) 

P=0.207N 

Logistic regression testd 

Cochran-Armitage testd 

Fisher exact testd 

P=0.107N 

P=0.086N 

P=0.275N 

P=0.339N 

P=0.074N 

P=0.059N 

P=0.207N 

P=0.181N 

Harderian Gland: Adenoma or Carcinoma 

Overall rate 5/50 (10%) 2/50 (4%) 1/50 (2%) 2/50 (4%) 

Adjusted rate 14.7% 5.1% 2.8% 6.5% 

Terminal rate 5/34 (15%) 2/39 (5%) 0/31 (0%) 2/31 (6%) 

First incidence (days) 731 (T) 731 (T) 689 731 (T) 

Life table test P=0.200N P=0.163N P=0.125N P=0.253N 

Logistic regression test P=0.173N P=0.163N P=0.121N P=0.253N 

Cochran-Armitage test P=0.162N 

Fisher exact test P=0.218N P=0.102N P=0.218N 

Liver: Hepatocellular Adenoma 

Overall rate 20/50 (40%) 18/50 (36%) 17/50 (34%) 28/50 (56%) 

Adjusted rate 53.6% 44.9% 53.1% 67.5% 

Terminal rate 17/34 (50%) 17/39 (44%) 16/31 (52%) 18/31 (58%) 

First incidence (days) 607 648 722 467 

Life table test P=0.010 P=0.234N P=0.475N P=0.058 

Logistic regression test P=0.032 P=0.317N P=0.457N P=0.082 

Cochran-Armitage test P=0.043 

Fisher exact test P=0.418N P=0.339N P=0.080 

Liver: Hepatocellular Carcinoma 

Overall rate 12/50 (24%) 17/50 (34%) 11/50 (22%) 15/50 (30%) 

Adjusted rate 30.3% 37.6% 30.7% 40.4% 

Terminal rate 8/34 (24%) 11/39 (28%) 7/31 (23%) 10/31 (32%) 

First incidence (days) 470 527 556 556 

Life table test P=0.309 P=0.314 P=0.588N P=0.273 

Logistic regression test P=0.411 P=0.159 P=0.544N P=0.325 

Cochran-Armitage test P=0.426 

Fisher exact test P=0.189 P=0.500N P=0.326 

Liver: Hepatocellular Adenoma or Carcinoma 

Overall rate 27/50 (54%) 29/50 (58%) 23/50 (46%) 36/50 (72%) 

Adjusted rate 65.2% 63.0% 63.6% 85.3% 

Terminal rate 20/34 (59%) 22/39 (56%) 18/31 (58%) 25/31 (81%) 

First incidence (days) 470 527 556 467 

Life table test P=0.018 P=0.478N P=0.443N P=0.038 

Logistic regression test P=0.040 P=0.463 P=0.394N P=0.046 

Cochran-Armitage test P=0.053 

Fisher exact test P=0.420 P=0.274N P=0.048 
AZT and AZT/"-Interferon A/D, NTP TR 469 113 

TABLE B2 

Statistical Analysis of Primary Neoplasms in Female Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Liver: Hepatocellular Carcinoma or Hepatoblastoma 

Overall rate 13/50 (26%) 17/50 (34%) 11/50 (22%) 16/50 (32%) 

Adjusted rate 33.0% 37.6% 30.7% 43.2% 

Terminal rate 9/34 (26%) 11/39 (28%) 7/31 (23%) 11/31 (35%) 

First incidence (days) 470 527 556 556 

Life table test P=0.288 P=0.396 P=0.503N P=0.271 

Logistic regression test P=0.390 P=0.225 P=0.455N P=0.329 

Cochran-Armitage test P=0.406 

Fisher exact test P=0.257 P=0.408N P=0.330 

Liver: Hepatocellular Adenoma, Hepatocellular Carcinoma, or Hepatoblastoma 

Overall rate 27/50 (54%) 29/50 (58%) 23/50 (46%) 36/50 (72%) 

Adjusted rate 65.2% 63.0% 63.6% 85.3% 

Terminal rate 20/34 (59%) 22/39 (56%) 18/31 (58%) 25/31 (81%) 

First incidence (days) 470 527 556 467 

Life table test P=0.018 P=0.478N P=0.443N P=0.038 

Logistic regression test P=0.040 P=0.463 P=0.394N P=0.046 

Cochran-Armitage test P=0.053 

Fisher exact test P=0.420 P=0.274N P=0.048 

Lung: Alveolar/bronchiolar Adenoma 

Overall rate 3/49 (6%) 3/50 (6%) 2/50 (4%) 7/50 (14%) 

Adjusted rate 7.6% 7.7% 5.3% 21.5% 

Terminal rate 1/34 (3%) 3/39 (8%) 1/31 (3%) 6/31 (19%) 

First incidence (days) 647 731 (T) 288 709 

Life table test P=0.057 P=0.611N P=0.538N P=0.140 

Logistic regression test P=0.082 P=0.649N P=0.415N P=0.164 

Cochran-Armitage test P=0.083 

Fisher exact test P=0.651N P=0.490N P=0.167 

Lung: Alveolar/bronchiolar Carcinoma 

Overall rate 3/49 (6%) 5/50 (10%) 0/50 (0%) 4/50 (8%) 

Adjusted rate 8.8% 11.6% 0.0% 10.4% 

Terminal rate 3/34 (9%) 3/39 (8%) 0/31 (0%) 1/31 (3%) 

First incidence (days) 731 (T) 589 — 625 

Life table test P=0.532 P=0.426 P=0.137N P=0.480 

Logistic regression test P=0.578N P=0.365 P=0.137N P=0.509 

Cochran-Armitage test P=0.572N 

Fisher exact test P=0.369 P=0.117N P=0.511 

Lung: Alveolar/bronchiolar Adenoma or Carcinoma 

Overall rate 6/49 (12%) 8/50 (16%) 2/50 (4%) 11/50 (22%) 

Adjusted rate 16.0% 18.9% 5.3% 30.3% 

Terminal rate 4/34 (12%) 6/39 (15%) 1/31 (3%) 7/31 (23%) 

First incidence (days) 647 589 288 625 

Life table test P=0.101 P=0.479 P=0.169N P=0.128 

Logistic regression test P=0.142 P=0.405 P=0.112N P=0.151 

Cochran-Armitage test P=0.146 

Fisher exact test P=0.403 P=0.128N P=0.154 
114 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE B2 

Statistical Analysis of Primary Neoplasms in Female Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Ovary: Cystadenoma 

Overall rate 2/50 (4%) 2/50 (4%) 3/47 (6%) 0/48 (0%) 

Adjusted rate 5.9% 4.7% 10.0% 0.0% 

Terminal rate 2/34 (6%) 1/39 (3%) 2/28 (7%) 0/29 (0%) 

First incidence (days) 731 (T) 617 713 — 

Life table test P=0.251N P=0.648N P=0.422 P=0.274N 

Logistic regression test P=0.221N P=0.691N P=0.417 P=0.274N 

Cochran-Armitage test P=0.213N 

Fisher exact test P=0.691N P=0.470 P=0.258N 

Pituitary Gland (Pars Distalis): Adenoma 

Overall rate 2/46 (4%) 5/49 (10%) 1/46 (2%) 0/46 (0%) 

Adjusted rate 6.3% 12.1% 3.4% 0.0% 

Terminal rate 2/32 (6%) 4/39 (10%) 1/29 (3%) 0/29 (0%) 

First incidence (days) 731 (T) 589 731 (T) — 

Life table test P=0.093N P=0.295 P=0.535N P=0.260N 

Logistic regression test P=0.077N P=0.257 P=0.535N P=0.260N 

Cochran-Armitage test P=0.073N 

Fisher exact test P=0.245 P=0.500N P=0.247N 

Stomach (Forestomach): Squamous Cell Papilloma 

Overall rate 3/50 (6%) 3/50 (6%) 1/50 (2%) 1/50 (2%) 

Adjusted rate 8.8% 7.7% 3.2% 3.2% 

Terminal rate 3/34 (9%) 3/39 (8%) 1/31 (3%) 1/31 (3%) 

First incidence (days) 731 (T) 731 (T) 731 (T) 731 (T) 

Life table test P=0.202N P=0.599N P=0.338N P=0.338N 

Logistic regression test P=0.202N P=0.599N P=0.338N P=0.338N 

Cochran-Armitage test P=0.165N 

Fisher exact test P=0.661N P=0.309N P=0.309N 

Stomach (Forestomach): Squamous Cell Papilloma or Squamous Cell Carcinoma 

Overall rate 3/50 (6%) 3/50 (6%) 1/50 (2%) 2/50 (4%) 

Adjusted rate 8.8% 7.7% 3.2% 5.4% 

Terminal rate 3/34 (9%) 3/39 (8%) 1/31 (3%) 1/31 (3%) 

First incidence (days) 731 (T) 731 (T) 731 (T) 612 

Life table test P=0.399N P=0.599N P=0.338N P=0.529N 

Logistic regression test P=0.351N P=0.599N P=0.338N P=0.498N 

Cochran-Armitage test P=0.343N 

Fisher exact test P=0.661N P=0.309N P=0.500N 

Thyroid Gland (Follicular Cell): Adenoma 

Overall rate 3/49 (6%) 2/50 (4%) 4/50 (8%) 0/50 (0%) 

Adjusted rate 8.1% 5.1% 12.9% 0.0% 

Terminal rate 2/34 (6%) 2/39 (5%) 4/31 (13%) 0/31 (0%) 

First incidence (days) 647 731 (T) 731 (T) — 

Life table test P=0.170N P=0.446N P=0.449 P=0.134N 

Logistic regression test P=0.142N P=0.475N P=0.460 P=0.118N 

Cochran-Armitage test P=0.132N 

Fisher exact test P=0.490N P=0.511 P=0.117N 
 

AZT and AZT/"-Interferon A/D, NTP TR 469 115 

TABLE B2 

Statistical Analysis of Primary Neoplasms in Female Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Thyroid Gland (Follicular Cell): Adenoma or Carcinoma 

Overall rate 4/49 (8%) 3/50 (6%) 4/50 (8%) 0/50 (0%)
 

Adjusted rate 10.7% 7.7% 12.9% 0.0%
 

Terminal rate 2/34 (6%) 3/39 (8%) 4/31 (13%) 0/31 (0%)
 

First incidence (days) 647 731 (T) 731 (T) —
 

Life table test P=0.088N P=0.438N P=0.586 P=0.077N 

Logistic regression test P=0.068N P=0.467N P=0.603 P=0.061N 

Cochran-Armitage test P=0.061N
 

Fisher exact test P=0.489N P=0.631N P=0.056N 

Vagina: Squamous Cell Carcinoma 

Overall rate 0/50 (0%) 0/49 (0%) 5/45 (11%) 9/49 (18%) 

Adjusted rate 0.0% 0.0% 12.8% 26.8% 

Terminal rate 0/34 (0%) 0/39 (0%) 1/30 (3%) 7/31 (23%) 

First incidence (days) — — 493 695 

f Life table test P<0.001 — P=0.031 P=0.002 

Logistic regression test P<0.001 — P=0.028 P=0.002 

Cochran-Armitage test P<0.001 

Fisher exact test — P=0.021 P=0.001 

Vagina: Squamous Cell Papilloma or Squamous Cell Carcinoma 

Overall rate 0/50 (0%) 0/49 (0%) 5/45 (11%) 11/49 (22%) 

Adjusted rate 0.0% 0.0% 12.8% 32.9% 

Terminal rate 0/34 (0%) 0/39 (0%) 1/30 (3%) 9/31 (29%) 

First incidence (days) — — 493 695 

Life table test P<0.001 — P=0.031 P<0.001 

Logistic regression test P<0.001 — P=0.028 P<0.001 

Cochran-Armitage test P<0.001 

Fisher exact test — P=0.021 P<0.001 

All Organs: Hemangioma or Hemangiosarcoma 

Overall rate 1/50 (2%) 2/50 (4%) 2/50 (4%) 4/50 (8%) 

Adjusted rate 2.2% 5.1% 4.7% 9.8% 

Terminal rate 0/34 (0%) 2/39 (5%) 0/31 (0%) 0/31 (0%) 

First incidence (days) 523 731 (T) 556 601 

Life table test P=0.109 P=0.541 P=0.487 P=0.189 

Logistic regression test P=0.119 P=0.445 P=0.603 P=0.189 

Cochran-Armitage test P=0.113 

Fisher exact test P=0.500 P=0.500 P=0.181 

All Organs: Histiocytic Sarcoma 

Overall rate 2/50 (4%) 1/50 (2%) 3/50 (6%) 1/50 (2%) 

Adjusted rate 4.0% 2.0% 8.3% 2.7% 

Terminal rate 0/34 (0%) 0/39 (0%) 1/31 (3%) 0/31 (0%) 

First incidence (days) 379 527 582 709 

Life table test P=0.486N P=0.488N P=0.461 P=0.499N 

Logistic regression test P=0.404N P=0.319 P=0.637 P=0.396N 

Cochran-Armitage test P=0.474N 

Fisher exact test P=0.500N P=0.500 P=0.500N 
116 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE B2 

Statistical Analysis of Primary Neoplasms in Female Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

All Organs: Malignant Lymphoma 

Overall rate 5/50 (10%) 10/50 (20%) 7/50 (14%) 9/50 (18%) 

Adjusted rate 12.6% 24.0% 18.4% 25.3% 

Terminal rate 2/34 (6%) 8/39 (21%) 3/31 (10%) 6/31 (19%) 

First incidence (days) 603 636 219 625 

Life table test P=0.203 P=0.195 P=0.328 P=0.180 

Logistic regression test P=0.268 P=0.139 P=0.450 P=0.194 

Cochran-Armitage test P=0.265 

Fisher exact test P=0.131 P=0.380 P=0.194 

All Organs: Benign Neoplasms 

Overall rate 30/50 (60%) 33/50 (66%) 26/50 (52%) 31/50 (62%) 

Adjusted rate 76.7% 76.6% 69.8% 73.3% 

Terminal rate 25/34 (74%) 29/39 (74%) 20/31 (65%) 20/31 (65%) 

First incidence (days) 607 589 288 467 

Life table test P=0.288 P=0.504N P=0.462N P=0.362 

Logistic regression test P=0.535N P=0.490 P=0.414N P=0.534 

Cochran-Armitage test P=0.500N 

Fisher exact test P=0.339 P=0.273N P=0.500 

All Organs: Malignant Neoplasms 

Overall rate 26/50 (52%) 30/50 (60%) 28/50 (56%) 35/50 (70%) 

Adjusted rate 55.8% 62.5% 60.8% 77.4% 

Terminal rate 14/34 (41%) 21/39 (54%) 13/31 (42%) 21/31 (68%) 

First incidence (days) 379 527 219 556 

Life table test P=0.044 P=0.500 P=0.309 P=0.071 

Logistic regression test P=0.031 P=0.190 P=0.335 P=0.051 

Cochran-Armitage test P=0.051 

Fisher exact test P=0.273 P=0.421 P=0.050 

All Organs: Benign or Malignant Neoplasms 

Overall rate 41/50 (82%) 42/50 (84%) 41/50 (82%) 43/50 (86%) 

Adjusted rate 85.3% 87.5% 87.2% 91.4% 

Terminal rate 27/34 (79%) 33/39 (85%) 25/31 (81%) 27/31 (87%) 

First incidence (days) 379 527 219 467 

Life table test P=0.161 P=0.318N P=0.345 P=0.293 

Logistic regression test P=0.317 P=0.480 P=0.535 P=0.382 

Cochran-Armitage test P=0.362 

Fisher exact test P=0.500 P=0.602N P=0.393 

(T)Terminal sacrifice 

a Number of neoplasm-bearing animals/number of animals examined. Denominator is number of animals examined microscopically for liver, lung, ovary, 

pituitary gland, thyroid gland, and vagina; for other tissues, denominator is number of animals necropsied. b Kaplan-Meier estimated neoplasm incidence at the end of the study after adjustment for intercurrent mortality 

Observed incidence at terminal kill 

d	 Beneath the vehicle control incidence are the P values associated with the trend test. Beneath the dosed group incidence are the P values corresponding to 

pairwise comparisons between the vehicle controls and that dosed group. The life table test regards neoplasms in animals dying prior to terminal kill as being 

(directly or indirectly) the cause of death. The logistic regression test regards these lesions as nonfatal. The Cochran-Armitage and Fisher exact tests compare 

directly the overall incidence rates. For all tests, a negative trend or a lower incidence in a dose group is indicated by N. e Not applicable; no neoplasms in animal group f Value of statistic cannot be computed. 
AZT and AZT/"-Interferon A/D, NTP TR 469 117 

TABLE B3 

Historical Incidence of Liver Neoplasms in Water Gavage Vehicle Control Female B6C3F a 1 Mice

Incidence in Controls 

Hepatocellular 

Adenoma 

Hepatocellular 

Carcinoma 

Hepatoblastoma Hepatocellular Adenoma, 

Hepatocellular Carcinoma, 

or Hepatoblastoma 

Overall Historical Incidence 

Total 

Standard deviation 

Range 

28/366 (7.7%) 

9.8% 

2%-29% 

16/366 (4.4%) 

5.4% 

0%-16% 

0/366 43/366 (11.8%) 

14.2% 

2%-43% 

a Data as of 12 May 1995 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

118 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE B4 

Summary of the Incidence of Nonneoplastic Lesions in Female Mice in the 2-Year Gavage Study of AZTa 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Disposition Summary 

Animals initially in study 50 50 50 50 

Early deaths 

Accidental deaths 3 1 

Moribund 5 5 9 7 

Natural deaths 11 6 7 11 

Survivors 

Died last week of study 1 

Terminal sacrifice 34 38 31 31 

Animals examined microscopically 50 50 50 50 

Alimentary System 

Esophagus (50) (49) (50) (50) 

Necrosis 1 (2%) 

Muscularis, inflammation, chronic 1 (2%) 1 (2%) 

Intestine large, colon (46) (48) (46) (45) 

Inflammation, chronic 1 (2%) 

Intestine large, cecum (46) (47) (46) (45) 

Hemorrhage 1 (2%) 

Inflammation, chronic 1 (2%) 

Intestine small, duodenum (46) (45) (46) (44) 

Erosion 1 (2%) 

Intestine small, jejunum (46) (46) (44) (42) 

Peyer’s patch, hyperplasia, lymphoid 1 (2%) 

Intestine small, ileum (46) (44) (45) (42) 

Peyer’s patch, hyperplasia, lymphoid 1 (2%) 

Liver (50) (50) (50) (50) 

Angiectasis 1 (2%) 

Basophilic focus 1 (2%) 3 (6%) 

Clear cell focus 1 (2%) 3 (6%) 1 (2%) 

Eosinophilic focus 6 (12%) 16 (32%) 7 (14%) 7 (14%) 

Fibrosis, focal 1 (2%) 

Hematopoietic cell proliferation 1 (2%) 1 (2%) 1 (2%) 

Hepatodiaphragmatic nodule 1 (2%) 

Inflammation, chronic 1 (2%) 2 (4%) 2 (4%) 1 (2%) 

Mixed cell focus 1 (2%) 1 (2%) 5 (10%) 

Necrosis, focal 3 (6%) 3 (6%) 2 (4%) 10 (20%) 

Vacuolization cytoplasmic 3 (6%) 4 (8%) 3 (6%) 3 (6%) 

Hepatocyte, karyomegaly 1 (2%) 1 (2%) 

Mesentery (13) (17) (8) (11) 

Inflammation, chronic 1 (8%) 1 (9%) 

Fat, necrosis 8 (62%) 16 (94%) 5 (63%) 10 (91%) 

Pancreas (50) (49) (49) (48) 

Atrophy 1 (2%) 1 (2%) 2 (4%) 1 (2%) 

Atrophy, diffuse 1 (2%) 

Inflammation, chronic 2 (4%) 

Necrosis 1 (2%) 

Duct, cyst 2 (4%) 1 (2%) 1 (2%) 1 (2%) 

a Number of animals examined microscopically at the site and the number of animals with lesion 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 119 

TABLE B4 

Summary of the Incidence of Nonneoplastic Lesions in Female Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Alimentary System (continued) 

Stomach, forestomach (49) (49) (49) (49) 

Cyst 1 (2%) 

Erosion 1 (2%) 

Hemorrhage 1 (2%) 

Inflammation, chronic 1 (2%) 2 (4%) 

Ulcer 1 (2%) 1 (2%) 

Epithelium, hyperplasia 4 (8%) 9 (18%) 7 (14%) 3 (6%) 

Stomach, glandular (49) (49) (48) (49) 

Erosion 1 (2%) 2 (4%) 1 (2%) 1 (2%) 

Mineralization 1 (2%) 1 (2%) 

Necrosis 1 (2%) 

Glands, degeneration, cystic, focal 1 (2%) 1 (2%) 4 (8%) 4 (8%) 

Cardiovascular System 

Heart (49) (50) (50) (50) 

Inflammation, chronic, focal 1 (2%) 4 (8%) 3 (6%) 3 (6%) 

Mineralization 1 (2%) 1 (2%) 

Thrombosis 1 (2%) 

Endocrine System 

Adrenal cortex (50) (49) (50) (50) 

Accessory adrenal cortical nodule 1 (2%) 

Cyst 1 (2%) 

Cytoplasmic alteration, focal 4 (8%) 4 (8%) 2 (4%) 

Hematopoietic cell proliferation 1 (2%) 

Hyperplasia, focal 1 (2%) 1 (2%) 

Hypertrophy, focal 2 (4%) 1 (2%) 4 (8%) 

Islets, pancreatic (49) (49) (50) (47) 

Hyperplasia 2 (4%) 

Parathyroid gland (47) (45) (48) (50) 

Cyst 1 (2%) 1 (2%) 

Pituitary gland (46) (49) (46) (46) 

Angiectasis 1 (2%) 2 (4%) 1 (2%) 

Pars distalis, cyst 1 (2%) 

Pars distalis, cytoplasmic alteration, focal 7 (15%) 1 (2%) 3 (7%) 

Pars distalis, hyperplasia, focal 4 (9%) 7 (14%) 6 (13%) 5 (11%) 

Pars intermedia, hyperplasia, focal 2 (4%) 

Thyroid gland (49) (50) (50) (50) 

Degeneration, cystic, focal 25 (51%) 19 (38%) 23 (46%) 20 (40%) 

Follicle, cyst 2 (4%) 6 (12%) 2 (4%) 7 (14%) 

Follicular cell, hyperplasia 6 (12%) 11 (22%) 5 (10%) 11 (22%) 

General Body System 

None 

Genital System 

Clitoral gland (49) (49) (49) (48) 

Degeneration, cystic 35 (71%) 46 (94%) 33 (67%) 43 (90%) 

Inflammation, chronic 1 (2%) 1 (2%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

120 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE B4 

Summary of the Incidence of Nonneoplastic Lesions in Female Mice in the 2-Year Gavage Study of AZT

 Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Genital System (continued) 

Ovary (50) (50) (47) (48) 

Angiectasis 1 (2%) 

Cyst 10 (20%) 10 (20%) 5 (11%) 10 (21%) 

Hemorrhage 3 (6%) 1 (2%) 1 (2%) 

Hyperplasia, tubular 1 (2%) 

Thrombosis 1 (2%) 1 (2%) 

Bilateral, cyst 1 (2%) 

Uterus (50) (50) (49) (50) 

Cyst 3 (6%) 

Hemorrhage 1 (2%) 2 (4%) 2 (4%) 1 (2%) 

Hydrometra 11 (22%) 20 (40%) 22 (45%) 13 (26%) 

Inflammation, suppurative 1 (2%) 1 (2%) 1 (2%) 1 (2%) 

Thrombosis 1 (2%) 2 (4%) 

Endometrium, hyperplasia, cystic 45 (90%) 45 (90%) 36 (73%) 42 (84%) 

Vagina (50) (49) (45) (49) 

Cyst 1 (2%) 

Fibrosis 1 (2%) 

Inflammation, suppurative 1 (2%) 

Epithelium, hyperplasia 3 (6%) 2 (4%) 7 (14%) 

Epithelium, hyperplasia, atypical 2 (4%) 4 (8%) 

Hematopoietic System 

Bone marrow (50) (49) (50) (50) 

Angiectasis 1 (2%) 1 (2%) 

Hyperplasia 1 (2%) 3 (6%) 3 (6%) 7 (14%) 

Necrosis 1 (2%) 

Lymph node (7) (5) (7) (10) 

Bronchial, hyperplasia 1 (14%) 

Iliac, ectasia 1 (10%) 

Iliac, hematopoietic cell proliferation 1 (14%) 

Iliac, hemorrhage 1 (20%) 

Iliac, hyperplasia, histiocytic 1 (14%) 

Inguinal, hyperplasia, histiocytic 1 (10%) 

Inguinal, hyperplasia, lymphoid 1 (20%) 1 (14%) 2 (20%) 

Mediastinal, hemorrhage 1 (14%) 1 (20%) 

Mediastinal, hyperplasia, histiocytic 1 (10%) 

Mediastinal, hyperplasia, lymphoid 1 (10%) 

Renal, hyperplasia, lymphoid 1 (10%) 

Lymph node, mandibular (50) (46) (48) (48) 

Hemorrhage 1 (2%) 1 (2%) 

Hyperplasia, lymphoid 2 (4%) 3 (6%) 6 (13%) 

Infiltration cellular, mast cell 1 (2%) 1 (2%) 

Lymph node, mesenteric (50) (47) (48) (47) 

Ectasia 1 (2%) 2 (4%) 

Hematopoietic cell proliferation 1 (2%) 

Hemorrhage 3 (6%) 5 (11%) 2 (4%) 5 (11%) 

Hyperplasia, lymphoid 5 (11%) 3 (6%) 5 (11%) 

Spleen (49) (48) (49) (50) 

Congestion 1 (2%) 2 (4%) 

Depletion cellular 1 (2%) 3 (6%) 1 (2%) 

Hematopoietic cell proliferation 13 (27%) 12 (25%) 10 (20%) 14 (28%) 

Hyperplasia, lymphoid 8 (16%) 6 (13%) 2 (4%) 6 (12%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 121 

TABLE B4 

Summary of the Incidence of Nonneoplastic Lesions in Female Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Hematopoietic System (continued) 

Thymus (48) (46) (49) (46) 

Angiectasis 1 (2%) 

Cyst 3 (6%) 1 (2%) 

Hyperplasia, lymphoid 4 (8%) 1 (2%) 1 (2%) 4 (9%) 

Necrosis 2 (4%) 2 (4%) 

Integumentary System 

Mammary gland (47) (47) (48) (47) 

Hyperplasia 3 (6%) 1 (2%) 

Skin (50) (49) (50) (50) 

Inflammation, chronic, focal 1 (2%) 1 (2%) 

Subcutaneous tissue, cyst epithelial

 inclusion 1 (2%) 

Subcutaneous tissue, edema 1 (2%) 

Musculoskeletal System 

Bone (50) (50) (50) (50) 

Fibrous osteodystrophy 4 (8%) 

Hyperostosis 37 (74%) 35 (70%) 33 (66%) 37 (74%) 

Cranium, fibrous osteodystrophy 1 (2%) 

Skeletal muscle (50) (50) (50) (50) 

Hyperplasia, focal, lymphoid 1 (2%) 

Inflammation, suppurative 1 (2%) 

Nervous System 

Brain (50) (50) (50) (50) 

Atrophy, focal 1 (2%) 3 (6%) 

Hemorrhage 1 (2%) 

Vacuolization cytoplasmic 1 (2%) 1 (2%) 

Respiratory System 

Lung (49) (50) (50) (50) 

Congestion 2 (4%) 1 (2%) 

Foreign body 1 (2%) 1 (2%) 

Hemorrhage 3 (6%) 3 (6%) 1 (2%) 

Hyperplasia, histiocytic 2 (4%) 1 (2%) 2 (4%) 

Infiltration cellular, mixed cell 1 (2%) 

Pigmentation 1 (2%) 1 (2%) 

Alveolar epithelium, hyperplasia 2 (4%) 4 (8%) 1 (2%) 

Mediastinum, hemorrhage 1 (2%) 1 (2%) 

Mediastinum, inflammation, chronic 2 (4%) 1 (2%) 

Mediastinum, necrosis 1 (2%) 

Nose (50) (50) (50) (50) 

Hemorrhage 1 (2%) 

Mucosa, glands, dilatation, focal 1 (2%) 2 (4%) 2 (4%) 

Nasolacrimal duct, cyst 1 (2%) 
 

 

 

 

 

 

 

 

 

122 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE B4 

Summary of the Incidence of Nonneoplastic Lesions in Female Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Special Senses System 

Eye (3) (1) 

Cataract 1 (33%) 

Fibrosis 2 (67%) 

Cornea, inflammation, chronic 1 (100%) 

Urinary System 

Kidney (50) (50) (50) (50) 

Cyst 1 (2%) 

Fibrosis, focal 1 (2%) 

Infarct 1 (2%) 2 (4%) 

Metaplasia, focal, osseous 1 (2%) 2 (4%) 

Nephropathy 29 (58%) 30 (60%) 31 (62%) 35 (70%) 

Pelvis, dilatation 3 (6%) 3 (6%) 

Renal tubule, accumulation, hyaline droplet 1 (2%) 1 (2%) 

Renal tubule, dilatation 1 (2%) 1 (2%) 3 (6%) 

Renal tubule, necrosis 1 (2%) 

Renal tubule, pigmentation 2 (4%) 1 (2%) 2 (4%) 

Transitional epithelium, hyperplasia 1 (2%) 

Urinary bladder (50) (50) (49) (49) 

Hyperplasia, lymphoid 1 (2%) 1 (2%) 
123 

APPENDIX C 

SUMMARY OF LESIONS IN MALE MICE 

IN THE 2-YEAR SUBCUTANEOUS STUDY 

OF "-INTERFERON A/D 

TABLE C1 Summary of the Incidence of Neoplasms in Male Mice 

in the 2-Year Subcutaneous Study of "-Interferon A/D ....................... 124 

TABLE C2 Statistical Analysis of Primary Neoplasms in Male Mice 

in the 2-Year Subcutaneous Study of "-Interferon A/D ....................... 128 

TABLE C3 Summary of the Incidence of Nonneoplastic Lesions in Male Mice 

in the 2-Year Subcutaneous Study of "-Interferon A/D ....................... 133 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

124 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE C1 

Summary of the Incidence of Neoplasms in Male Mice in the 2-Year Subcutaneous Study of "-Interferon A/Da 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Disposition Summary 

Animals initially in study 50 50 50 50 

Early deaths 

Accidental death 1 

Moribund 13 10 7 10 

Natural deaths 10 13 15 11 

Survivors 

Terminal sacrifice 27 27 28 28 

Animals examined microscopically 50 50 50 50 

Alimentary System 

Gallbladder (45) (43) (45) (48) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 

Intestine small, duodenum (49) (47) (49) 

Fibrosarcoma, metastatic, mesentery 1 (2%) 

Polyp adenomatous 1 (2%) 

Intestine small, jejunum (49) (50) (47) (49) 

Carcinoma 1 (2%) 1 (2%) 1 (2%) 

Hepatoblastoma, metastatic, liver 1 (2%) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 

Intestine small, ileum (49) (50) (47) (49) 

Fibrous histiocytoma 1 (2%) 

Hepatoblastoma, metastatic, liver 1 (2%) 

Liver (50) (50) (50) (50) 

Fibrosarcoma, metastatic, mesentery 1 (2%) 

Fibrous histiocytoma 1 (2%) 

Hemangioma, multiple 1 (2%) 

Hemangiosarcoma 1 (2%) 2 (4%) 1 (2%) 2 (4%) 

Hemangiosarcoma, multiple 3 (6%) 2 (4%) 3 (6%) 2 (4%) 

Hepatoblastoma 2 (4%) 3 (6%) 1 (2%) 1 (2%) 

Hepatocellular carcinoma 10 (20%) 13 (26%) 17 (34%) 10 (20%) 

Hepatocellular carcinoma, multiple 8 (16%) 6 (12%) 6 (12%) 4 (8%) 

Hepatocellular adenoma 11 (22%) 14 (28%) 10 (20%) 11 (22%) 

Hepatocellular adenoma, multiple 3 (6%) 5 (10%) 4 (8%) 5 (10%) 

Hepatocholangiocarcinoma 1 (2%) 2 (4%) 1 (2%) 

Histiocytic sarcoma 1 (2%) 1 (2%) 

Mesentery (7) (9) (5) (6) 

Fibrosarcoma 1 (17%) 

Fibrous histiocytoma 1 (20%) 1 (17%) 

Hepatocholangiocarcinoma, metastatic, liver 1 (14%) 1 (11%) 1 (17%) 

Histiocytic sarcoma 1 (11%) 

Pancreas (49) (49) (49) (49) 

Fibrosarcoma, metastatic, mesentery 1 (2%) 

Fibrous histiocytoma, metastatic, mesentery 1 (2%) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 1 (2%) 1 (2%) 

Salivary glands (50) (50) (50) (49) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 

Stomach, forestomach (50) (48) (49) 

Squamous cell papilloma 1 (2%) 

Stomach, glandular (50) (50) (48) (49) 

Adenoma 1 (2%) 

Fibrosarcoma, metastatic, mesentery 1 (2%) 

Tooth (24) (14) (24) 

Odontoma 1 (4%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 125 

TABLE C1 

Summary of the Incidence of Neoplasms in Male Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Cardiovascular System 

Heart (50) (50) (50) (50) 

Hepatoblastoma, metastatic, liver 1 (2%) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 1 (2%) 

Endocrine System 

Adrenal cortex (50) (49) (49) (50) 

Fibrosarcoma, metastatic, mesentery 1 (2%) 

Hepatoblastoma, metastatic, liver 1 (2%) 

Bilateral, capsule, adenoma 1 (2%) 

Capsule, adenoma 1 (2%) 3 (6%) 1 (2%) 3 (6%) 

Adrenal medulla (49) (49) (49) (50) 

Fibrosarcoma, metastatic, mesentery 1 (2%) 

Pheochromocytoma benign 1 (2%) 1 (2%) 

Bilateral, pheochromocytoma benign 1 (2%) 1 (2%) 

Islets, pancreatic (50) (48) (50) 

Adenoma 1 (2%) 

Carcinoma 1 (2%) 

Thyroid gland (50) (50) (49) (50) 

Follicular cell, adenoma 1 (2%) 1 (2%) 

General Body System 

Peritoneum (1) 

Tissue NOS (1) (1) (2) (1) 

Hepatoblastoma, metastatic, liver 1 (100%) 

Genital System 

Epididymis (50) (50) (50) (50) 

Preputial gland (50) (50) (50) (50) 

Adenoma 1 (2%) 

Prostate (49) (49) (49) (50) 

Fibrosarcoma, metastatic, mesentery 1 (2%) 

Seminal vesicle (50) (50) (50) (50) 

Fibrosarcoma, metastatic, mesentery 1 (2%) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 

Testes (50) (50) (50) 

Sertoli cell, adenoma 1 (2%) 

Hematopoietic System 

Bone marrow (50) (50) (50) (50) 

Hemangiosarcoma 2 (4%) 

Histiocytic sarcoma 1 (2%) 

Lymph node (3) (3) (3) (6) 

Iliac, fibrous histiocytoma 1 (33%) 

Mediastinal, fibrosarcoma, metastatic,

 mesentery 1 (17%) 

Mediastinal, fibrous histiocytoma 1 (33%) 

Mediastinal, fibrous histiocytoma,

 metastatic, mesentery 1 (17%) 

Mediastinal, hepatocholangiocarcinoma,

 metastatic, liver 1 (33%) 1 (33%) 1 (17%) 

Mediastinal, histiocytic sarcoma 1 (33%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

126 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE C1 

Summary of the Incidence of Neoplasms in Male Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Hematopoietic System (continued) 

Lymph node (continued) (3) (3) (3) (6) 

Pancreatic, hepatocholangiocarcinoma,

 metastatic, liver 1 (33%) 

Renal, fibrous histiocytoma 1 (33%) 

Lymph node, mandibular (47) (45) 

Histiocytic sarcoma 1 (2%) 

Lymph node, mesenteric (50) (50) (48) (46) 

Fibrous histiocytoma, metastatic, mesentery 1 (2%) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 

Histiocytic sarcoma 1 (2%) 1 (2%) 

Spleen (49) (50) (49) (49) 

Fibrosarcoma, metastatic, mesentery 1 (2%) 

Fibrous histiocytoma 1 (2%) 

Hemangiosarcoma 5 (10%) 2 (4%) 

Histiocytic sarcoma 1 (2%) 1 (2%) 

Thymus (38) (38) (35) 

Fibrous histiocytoma 1 (3%) 

Integumentary System 

Skin (50) (50) (49) (50) 

Squamous cell papilloma 1 (2%) 

Subcutaneous tissue, hemangioma 1 (2%) 

Subcutaneous tissue, hemangiosarcoma 1 (2%) 

Subcutaneous tissue, hepatoblastoma,

 metastatic, liver 1 (2%) 

Subcutaneous tissue, histiocytic sarcoma 1 (2%) 

Subcutaneous tissue, sarcoma 1 (2%) 

Musculoskeletal System 

Skeletal muscle (50) (50) (50) (50) 

Fibrosarcoma, metastatic, mesentery 1 (2%) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 1 (2%) 1 (2%) 

Nervous System 

None 

Respiratory System 

Lung (50) (50) (50) (50) 

Alveolar/bronchiolar adenoma 8 (16%) 5 (10%) 10 (20%) 8 (16%) 

Alveolar/bronchiolar adenoma, multiple 1 (2%) 1 (2%) 1 (2%) 1 (2%) 

Alveolar/bronchiolar carcinoma 4 (8%) 3 (6%) 4 (8%) 3 (6%) 

Alveolar/bronchiolar carcinoma, multiple 1 (2%) 

Carcinoma, metastatic, harderian gland 1 (2%) 

Fibrosarcoma, metastatic, mesentery 1 (2%) 

Fibrous histiocytoma 1 (2%) 

Hepatoblastoma, metastatic, liver 1 (2%) 2 (4%) 

Hepatocellular carcinoma, metastatic, liver 6 (12%) 7 (14%) 10 (20%) 2 (4%) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 2 (4%) 1 (2%) 

Histiocytic sarcoma 1 (2%) 1 (2%) 
 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 127 

TABLE C1 

Summary of the Incidence of Neoplasms in Male Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Respiratory System (continued) 

Lung (continued) (50) (50) (50) (50) 

Mediastinum, fibrosarcoma, metastatic,

 mesentery 1 (2%) 

Mediastinum, fibrous histiocytoma,

 metastatic, mesentery 1 (2%) 

Mediastinum, hepatocholangiocarcinoma,

 metastatic, liver 1 (2%) 

Nose (50) (50) (50) (50) 

Carcinoma, metastatic, harderian gland 2 (4%) 

Special Senses System 

Harderian gland (4) (4) (6) (8) 

Adenoma 2 (50%) 3 (75%) 5 (83%) 4 (50%) 

Carcinoma 2 (50%) 1 (25%) 1 (17%) 1 (13%) 

Urinary System 

Kidney (49) (50) (49) (49) 

Fibrous histiocytoma 1 (2%) 

Hemangioma 1 (2%) 

Hepatoblastoma, metastatic, liver 1 (2%) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 1 (2%) 

Histiocytic sarcoma 1 (2%) 

Urinary bladder (49) (50) (49) (50) 

Hemangioma 1 (2%) 

Transitional epithelium, papilloma 1 (2%) 

Systemic Lesions 

Multiple organsb (50) (50) (50) (50) 

Histiocytic sarcoma 2 (4%) 1 (2%) 

Lymphoma malignant 4 (8%) 2 (4%) 2 (4%) 5 (10%) 

Mesothelioma malignant 1 (2%) 

Neoplasm Summary 

Total animals with primary neoplasmsc 42 47 40 41 

Total primary neoplasms 66 70 94 75 

Total animals with benign neoplasms 22 29 26 28 

Total benign neoplasms 29 34 38 39 

Total animals with malignant neoplasms 32 30 30 25 

Total malignant neoplasms 37 36 56 36 

Total animals with metastatic neoplasms 10 11 10 5 

Total metastatic neoplasms 26 22 10 24 

a Number of animals examined microscopically at the site and the number of animals with neoplasm b Number of animals with any tissue examined microscopically 

Primary neoplasms: all neoplasms except metastatic neoplasms c 
128 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE C2 

Statistical Analysis of Primary Neoplasms in Male Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Adrenal Cortex: Adenoma 

Overall ratea 

Adjusted rateb 1/50 (2%) 

3.7% 

3/49 (6%) 

10.9% 

1/49 (2%) 

3.6% 

4/50 (8%) 

12.8% 

Terminal ratec 1/27 (4%) 2/26 (8%) 1/28 (4%) 3/28 (11%) 

First incidence (days) 

Life table testd 728 (T) 

P=0.093 

723 

P=0.302 

728 (T) 

P=0.754N 

572 

P=0.185 

Logistic regression testd 

Cochran-Armitage testd 

Fisher exact testd 

P=0.088 

P=0.092 

P=0.312 

P=0.301 

P=0.754N 

P=0.747 

P=0.170 

P=0.181 

Harderian Gland: Adenoma 

Overall rate 2/50 (4%) 3/50 (6%) 5/50 (10%) 4/50 (8%) 

Adjusted rate 7.4% 9.5% 17.0% 12.8% 

Terminal rate 2/27 (7%) 2/27 (7%) 4/28 (14%) 3/28 (11%) 

First incidence (days) 728 (T) 567 661 583 

Life table test P=0.503 P=0.496 P=0.220 P=0.345 

Logistic regression test P=0.491 P=0.505 P=0.190 P=0.321 

Cochran-Armitage test P=0.495 

Fisher exact test P=0.500 P=0.218 P=0.339 

Harderian Gland: Adenoma or Carcinoma 

Overall rate 4/50 (8%) 4/50 (8%) 6/50 (12%) 5/50 (10%) 

Adjusted rate 12.6% 11.8% 20.4% 16.3% 

Terminal rate 2/27 (7%) 2/27 (7%) 5/28 (18%) 4/28 (14%) 

First incidence (days) 671 567 661 583 

Life table test P=0.592 P=0.638N P=0.353 P=0.500 

Logistic regression test P=0.578 P=0.643N P=0.328 P=0.480 

Cochran-Armitage test P=0.584 

Fisher exact test P=0.643N P=0.370 P=0.500 

Liver: Hemangiosarcoma 

Overall rate 4/50 (8%) 4/50 (8%) 4/50 (8%) 4/50 (8%) 

Adjusted rate 11.5% 11.7% 11.6% 11.5% 

Terminal rate 1/27 (4%) 2/27 (7%) 1/28 (4%) 2/28 (7%) 

First incidence (days) 503 532 615 571 

Life table test P=0.606 P=0.629N P=0.609 P=0.630 

Logistic regression test P=0.604N P=0.630 P=0.624N P=0.625N 

Cochran-Armitage test P=0.618 

Fisher exact test P=0.643N P=0.643N P=0.643N 

Liver: Hepatocellular Adenoma 

Overall rate 14/50 (28%) 19/50 (38%) 14/50 (28%) 16/50 (32%) 

Adjusted rate 43.3% 55.6% 45.5% 48.3% 

Terminal rate 10/27 (37%) 13/27 (48%) 12/28 (43%) 12/28 (43%) 

First incidence (days) 503 547 540 556 

Life table test P=0.390 P=0.208 P=0.579N P=0.430 

Logistic regression test P=0.351 P=0.205 P=0.521 P=0.374 

Cochran-Armitage test P=0.372 

Fisher exact test P=0.198 P=0.588N P=0.414 
AZT and AZT/"-Interferon A/D, NTP TR 469 129 

TABLE C2 

Statistical Analysis of Primary Neoplasms in Male Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Liver: Hepatocellular Carcinoma 

Overall rate 18/50 (36%) 19/50 (38%) 23/50 (46%) 14/50 (28%) 

Adjusted rate 45.4% 47.2% 57.3% 40.8% 

Terminal rate 7/27 (26%) 8/27 (30%) 12/28 (43%) 9/28 (32%) 

First incidence (days) 586 524 405 585 

Life table test P=0.133N P=0.519 P=0.200 P=0.308N 

Logistic regression test P=0.102N P=0.469 P=0.218 P=0.453N 

Cochran-Armitage test P=0.099N 

Fisher exact test P=0.500 P=0.208 P=0.260N 

Liver: Hepatocellular Adenoma or Carcinoma 

Overall rate 28/50 (56%) 33/50 (66%) 30/50 (60%) 26/50 (52%) 

Adjusted rate 67.1% 79.4% 73.9% 70.9% 

Terminal rate 14/27 (52%) 19/27 (70%) 18/28 (64%) 18/28 (64%) 

First incidence (days) 503 524 405 556 

Life table test P=0.335N P=0.282 P=0.386 P=0.447N 

Logistic regression test P=0.334N P=0.209 P=0.404 P=0.469N 

Cochran-Armitage test P=0.311N 

Fisher exact test P=0.206 P=0.420 P=0.421N 

Liver: Hepatoblastoma 

Overall rate 2/50 (4%) 3/50 (6%) 1/50 (2%) 1/50 (2%)
 

Adjusted rate 5.8% 10.6% 3.4% 3.6%
 

Terminal rate 1/27 (4%) 2/27 (7%) 0/28 (0%) 1/28 (4%)
 

First incidence (days) 566 723 720 728 (T)
 

Life table test P=0.530N P=0.503 P=0.503N P=0.499N
 

Logistic regression test P=0.542N P=0.505 P=0.499N P=0.501N
 

Cochran-Armitage test P=0.537N
 

Fisher exact test P=0.500 P=0.500N P=0.500N
 

Liver: Hepatocellular Carcinoma or Hepatoblastoma 

Overall rate 20/50 (40%) 21/50 (42%) 24/50 (48%) 15/50 (30%) 

Adjusted rate 49.2% 51.7% 58.7% 43.9% 

Terminal rate 8/27 (30%) 9/27 (33%) 12/28 (43%) 10/28 (36%) 

First incidence (days) 566 524 405 585 

Life table test P=0.114N P=0.519 P=0.257 P=0.251N 

Logistic regression test P=0.083N P=0.486 P=0.284 P=0.329N 

Cochran-Armitage test P=0.080N 

Fisher exact test P=0.500 P=0.273 P=0.201N 

Liver: Hepatocellular Adenoma, Hepatocellular Carcinoma, or Hepatoblastoma 

Overall rate 30/50 (60%) 34/50 (68%) 31/50 (62%) 26/50 (52%) 

Adjusted rate 70.3% 80.1% 74.8% 70.9% 

Terminal rate 15/27 (56%) 19/27 (70%) 18/28 (64%) 18/28 (64%) 

First incidence (days) 503 524 405 556 

Life table test P=0.236N P=0.341 P=0.448 P=0.322N 

Logistic regression test P=0.211N P=0.269 P=0.484 P=0.311N 

Cochran-Armitage test P=0.194N 

Fisher exact test P=0.266 P=0.500 P=0.273N 
130 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE C2 

Statistical Analysis of Primary Neoplasms in Male Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Lung: Alveolar/bronchiolar Adenoma 

Overall rate 9/50 (18%) 6/50 (12%) 11/50 (22%) 9/50 (18%) 

Adjusted rate 30.1% 20.5% 31.6% 29.6% 

Terminal rate 7/27 (26%) 5/27 (19%) 6/28 (21%) 7/28 (25%) 

First incidence (days) 603 591 540 656 

Life table test P=0.481N P=0.287N P=0.391 P=0.590N 

Logistic regression test P=0.498N P=0.270N P=0.364 P=0.577 

Cochran-Armitage test P=0.485N 

Fisher exact test P=0.288N P=0.402 P=0.602N 

Lung: Alveolar/bronchiolar Carcinoma 

Overall rate 5/50 (10%) 3/50 (6%) 4/50 (8%) 3/50 (6%) 

Adjusted rate 15.4% 9.5% 12.5% 10.0% 

Terminal rate 3/27 (11%) 2/27 (7%) 2/28 (7%) 2/28 (7%) 

First incidence (days) 469 567 622 689 

Life table test P=0.353N P=0.358N P=0.517N P=0.348N 

Logistic regression test P=0.363N P=0.363N P=0.501N P=0.366N 

Cochran-Armitage test P=0.356N 

Fisher exact test P=0.357N P=0.500N P=0.357N 

Lung: Alveolar/bronchiolar Adenoma or Carcinoma 

Overall rate 13/50 (26%) 9/50 (18%) 12/50 (24%) 11/50 (22%) 

Adjusted rate 40.1% 29.3% 34.7% 35.0% 

Terminal rate 9/27 (33%) 7/27 (26%) 7/28 (25%) 8/28 (29%) 

First incidence (days) 469 567 540 656 

Life table test P=0.401N P=0.237N P=0.516N P=0.393N 

Logistic regression test P=0.423N P=0.226N P=0.532N P=0.445N 

Cochran-Armitage test P=0.408N 

Fisher exact test P=0.235N P=0.500N P=0.408N 

Spleen: Hemangiosarcoma 

Overall rate 0/49 (0%) 0/50 (0%) 5/49 (10%) 2/49 (4%) 

Adjusted rate 0.0% 0.0% 15.5% 6.0% 

Terminal rate 0/27 (0%) 0/27 (0%) 3/28 (11%) 1/28 (4%) 

First incidence (days) 

Life table test 

—e 

P=0.632N 

— 

—f 

615 

P=0.033 

587 

P=0.233 

Logistic regression test P=0.631N — P=0.031 P=0.242 

Cochran-Armitage test P=0.629N 

Fisher exact test — P=0.028 P=0.247 

All Organs: Hemangiosarcoma 

Overall rate 4/50 (8%) 4/50 (8%) 6/50 (12%) 4/50 (8%) 

Adjusted rate 11.5% 11.7% 18.2% 11.5% 

Terminal rate 1/27 (4%) 2/27 (7%) 3/28 (11%) 2/28 (7%) 

First incidence (days) 503 532 615 571 

Life table test P=0.486N P=0.629N P=0.352 P=0.630 

Logistic regression test P=0.475N P=0.630 P=0.373 P=0.625N 

Cochran-Armitage test P=0.479N 

Fisher exact test P=0.643N P=0.370 P=0.643N 
AZT and AZT/"-Interferon A/D, NTP TR 469 131 

TABLE C2 

Statistical Analysis of Primary Neoplasms in Male Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

All Organs: Hemangioma or Hemangiosarcoma 

Overall rate 4/50 (8%) 5/50 (10%) 7/50 (14%) 5/50 (10%) 

Adjusted rate 11.5% 13.6% 21.5% 14.9% 

Terminal rate 1/27 (4%) 2/27 (7%) 4/28 (14%) 3/28 (11%) 

First incidence (days) 503 532 615 571 

Life table test P=0.568N P=0.507 P=0.253 P=0.494 

Logistic regression test P=0.569N P=0.475 P=0.258 P=0.512 

Cochran-Armitage test P=0.566N 

Fisher exact test P=0.500 P=0.262 P=0.500 

All Organs: Malignant Lymphoma 

Overall rate 4/50 (8%) 2/50 (4%) 2/50 (4%) 5/50 (10%) 

Adjusted rate 11.8% 7.1% 7.1% 16.3% 

Terminal rate 2/27 (7%) 1/27 (4%) 2/28 (7%) 3/28 (11%) 

First incidence (days) 603 725 728 (T) 656 

Life table test P=0.314 P=0.343N P=0.351N P=0.494 

Logistic regression test P=0.302 P=0.334N P=0.353N P=0.482 

Cochran-Armitage test P=0.309 

Fisher exact test P=0.339N P=0.339N P=0.500 

All Organs: Benign Neoplasms 

Overall rate 22/50 (44%) 29/50 (58%) 26/50 (52%) 28/50 (56%) 

Adjusted rate 63.7% 79.5% 73.8% 76.8% 

Terminal rate 15/27 (56%) 20/27 (74%) 19/28 (68%) 20/28 (71%) 

First incidence (days) 503 547 540 556 

Life table test P=0.230 P=0.136 P=0.273 P=0.184 

Logistic regression test P=0.166 P=0.119 P=0.166 P=0.110 

Cochran-Armitage test P=0.203 

Fisher exact test P=0.115 P=0.274 P=0.159 

All Organs: Malignant Neoplasms 

Overall rate 32/50 (64%) 30/50 (60%) 30/50 (60%) 25/50 (50%) 

Adjusted rate 69.1% 65.8% 69.2% 62.7% 

Terminal rate 13/27 (48%) 12/27 (44%) 15/28 (54%) 14/28 (50%) 

First incidence (days) 469 524 405 435 

Life table test P=0.173N P=0.420N P=0.514N P=0.199N 

Logistic regression test P=0.101N P=0.390N P=0.391N P=0.114N 

Cochran-Armitage test P=0.102N 

Fisher exact test P=0.418N P=0.418N P=0.113N 
132 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE C2 

Statistical Analysis of Primary Neoplasms in Male Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

All Organs: Benign or Malignant Neoplasms 

Overall rate 42/50 (84%) 47/50 (94%) 40/50 (80%) 41/50 (82%) 

Adjusted rate 89.3% 95.9% 90.7% 93.0% 

Terminal rate 22/27 (81%) 25/27 (93%) 24/28 (86%) 25/28 (89%) 

First incidence (days) 469 524 405 435 

Life table test P=0.525N P=0.304 P=0.497N P=0.509N 

Logistic regression test P=0.539 P=0.103 P=0.456N P=0.588N 

Cochran-Armitage test P=0.566N 

Fisher exact test P=0.100 P=0.398N P=0.500N 

(T)Terminal sacrifice 

a Number of neoplasm-bearing animals/number of animals examined. Denominator is number of animals examined microscopically for adrenal gland, liver, 

lung, and spleen; for other tissues, denominator is number of animals necropsied. b	 Kaplan-Meier estimated neoplasm incidence at the end of the study after adjustment for intercurrent mortality 

Observed incidence at terminal kill 

d	 Beneath the vehicle control incidence are the P values associated with the trend test (the "-IFN A group was excluded from the trend test). Beneath the dosed 

group incidence are the P values corresponding to pairwise comparisons between the vehicle controls and that dosed group. The life table test regards 

neoplasms in animals dying prior to terminal kill as being (directly or indirectly) the cause of death. The logistic regression test regards these lesions as 

nonfatal. The Cochran-Armitage and Fisher exact tests compare directly the overall incidence rates. For all tests, a negative trend or a lower incidence in a 

dosed group is indicated by N. e Not applicable; no neoplasms in animal group f Value of statistic cannot be computed. 
 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 133 

TABLE C3 

Summary of the Incidence of Nonneoplastic Lesions in Male Mice in the 2-Year Subcutaneous Study of "-Interferon 

A/Da 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Disposition Summary 

Animals initially in study 50 50 50 50 

Early deaths 

Accidental death 1 

Moribund 13 10 7 10 

Natural deaths 10 13 15 11 

Survivors 

Terminal sacrifice 27 27 28 28 

Animals examined microscopically 50 50 50 50 

Alimentary System 

Gallbladder (45) (45) (48) 

Inflammation, chronic 1 (2%) 

Intestine large, cecum (49) (50) (49) (49) 

Congestion 1 (2%) 1 (2%) 

Liver (50) (50) (50) (50) 

Angiectasis 1 (2%) 1 (2%) 1 (2%) 1 (2%) 

Basophilic focus 1 (2%) 1 (2%) 2 (4%) 

Clear cell focus 1 (2%) 2 (4%) 1 (2%) 6 (12%) 

Congestion 1 (2%) 

Eosinophilic focus 9 (18%) 5 (10%) 3 (6%) 4 (8%) 

Hematopoietic cell proliferation 1 (2%) 

Infarct 1 (2%) 

Inflammation, chronic 15 (30%) 20 (40%) 17 (34%) 18 (36%) 

Mixed cell focus 1 (2%) 2 (4%) 4 (8%) 

Necrosis, focal 4 (8%) 7 (14%) 1 (2%) 5 (10%) 

Pigmentation, focal 2 (4%) 3 (6%) 1 (2%) 

Vacuolization cytoplasmic 1 (2%) 1 (2%) 2 (4%) 

Bile duct, cyst 1 (2%) 

Bile duct, hyperplasia 8 (16%) 7 (14%) 9 (18%) 8 (16%) 

Centrilobular, necrosis 1 (2%) 

Hepatocyte, karyomegaly 12 (24%) 12 (24%) 14 (28%) 8 (16%) 

Mesentery (7) (9) (5) (6) 

Angiectasis 1 (14%) 1 (20%) 

Inflammation, chronic 1 (14%) 3 (33%) 1 (20%) 2 (33%) 

Artery, inflammation, chronic 2 (29%) 4 (44%) 1 (17%) 

Fat, necrosis 1 (14%) 

Pancreas (49) (49) (49) (49) 

Duct, cyst 1 (2%) 

Inflammation, chronic 1 (2%) 1 (2%) 

Acinus, atrophy, diffuse 2 (4%) 

Stomach, forestomach (50) (50) (48) (49) 

Diverticulum 1 (2%) 1 (2%) 1 (2%) 

Erosion 2 (4%) 2 (4%) 2 (4%) 

Inflammation, chronic 3 (6%) 1 (2%) 2 (4%) 4 (8%) 

Epithelium, cyst 1 (2%) 

Epithelium, hyperplasia 5 (10%) 2 (4%) 3 (6%) 5 (10%) 

Muscularis, serosa, inflammation, suppurative 1 (2%) 

a Number of animals examined microscopically at the site and the number of animals with lesion 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

134 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE C3 

Summary of the Incidence of Nonneoplastic Lesions in Male Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Alimentary System (continued) 

Stomach, glandular (50) (50) (48) (49) 

Erosion 1 (2%) 2 (4%) 

Inflammation, chronic 2 (4%) 

Metaplasia, hepatocyte 1 (2%) 1 (2%) 

Mineralization 1 (2%) 

Pigmentation, focal 3 (6%) 1 (2%) 2 (4%) 

Epithelium, hyperplasia 2 (4%) 

Glands, degeneration, cystic, focal 2 (4%) 2 (4%) 1 (2%) 

Muscularis, serosa, inflammation, suppurative 1 (2%) 

Tooth (24) (20) (14) (24) 

Developmental malformation 24 (100%) 20 (100%) 14 (100%) 24 (100%) 

Inflammation, chronic, suppurative 1 (4%) 

Cardiovascular System 

Blood vessel (50) (50) (50) (48) 

Mineralization 1 (2%) 

Heart (50) (50) (50) (50) 

Mineralization 1 (2%) 

Thrombosis 1 (2%) 1 (2%) 1 (2%) 

Artery, inflammation, chronic 1 (2%) 1 (2%) 

Endocrine System 

Adrenal cortex (50) (49) (49) (50) 

Accessory adrenal cortical nodule 1 (2%) 1 (2%) 1 (2%) 

Angiectasis 1 (2%) 

Cyst 1 (2%) 1 (2%) 

Cytoplasmic alteration, focal 3 (6%) 1 (2%) 2 (4%) 5 (10%) 

Hyperplasia, focal 1 (2%) 1 (2%) 

Inflammation, chronic, focal 1 (2%) 

Capsule, hyperplasia, focal 3 (6%) 6 (12%) 10 (20%) 3 (6%) 

Adrenal medulla (49) (49) (49) (50) 

Hyperplasia 6 (12%) 3 (6%) 1 (2%) 1 (2%) 

Islets, pancreatic (50) (50) (48) (50) 

Hyperplasia 1 (2%) 

Parathyroid gland (49) (43) (41) (45) 

Cyst 1 (2%) 1 (2%) 2 (4%) 

Pituitary gland (45) (41) (47) (47) 

Pars distalis, cyst 2 (4%) 1 (2%) 1 (2%) 2 (4%) 

Pars distalis, cytoplasmic alteration, focal 1 (2%) 1 (2%) 1 (2%) 

Pars distalis, hyperplasia, focal 1 (2%) 

Thyroid gland (50) (50) (49) (50) 

Degeneration, cystic, focal 3 (6%) 4 (8%) 3 (6%) 7 (14%) 

Inflammation, chronic, focal 1 (2%) 

C-cell, hyperplasia 1 (2%) 

Follicle, cyst 1 (2%) 1 (2%) 

Follicular cell, hyperplasia 7 (14%) 8 (16%) 6 (12%) 11 (22%) 

General Body System 

None 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 135 

TABLE C3 

Summary of the Incidence of Nonneoplastic Lesions in Male Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Genital System 

Coagulating gland (2) 

Inflammation, chronic 1 (50%) 

Epididymis (50) (50) (50) (50) 

Granuloma sperm 1 (2%) 1 (2%) 

Inflammation, chronic 1 (2%) 

Mineralization, focal 1 (2%) 

Spermatocele 1 (2%) 1 (2%) 

Preputial gland (50) (50) (50) (50) 

Degeneration, cystic 17 (34%) 11 (22%) 16 (32%) 14 (28%) 

Inflammation, chronic 2 (4%) 5 (10%) 3 (6%) 6 (12%) 

Prostate (49) (49) (49) (50) 

Inflammation, chronic, focal 2 (4%) 2 (4%) 4 (8%) 

Epithelium, hyperplasia, focal 1 (2%) 

Seminal vesicle (50) (50) (50) 

Inflammation, chronic 1 (2%) 1 (2%) 

Testes (50) (50) (50) (50) 

Cyst 1 (2%) 

Germinal epithelium, degeneration 1 (2%) 

Mineralization, focal 2 (4%) 

Hematopoietic System 

Bone marrow (50) (50) (50) (50) 

Angiectasis 1 (2%) 

Hyperplasia 1 (2%) 2 (4%) 

Hyperplasia, focal, histiocytic 1 (2%) 

Lymph node (3) (3) (3) (6) 

Iliac, hyperplasia 1 (33%) 

Inguinal, hyperplasia 1 (33%) 1 (17%) 

Inguinal, hyperplasia, lymphoid 1 (17%) 

Inguinal, pigmentation 1 (33%) 

Lymph node, mandibular (47) (45) (46) (45) 

Hyperplasia 1 (2%) 1 (2%) 

Lymph node, mesenteric (50) (50) (48) (46) 

Angiectasis 3 (6%) 1 (2%) 2 (4%) 1 (2%) 

Hematopoietic cell proliferation 2 (4%) 5 (10%) 3 (6%) 3 (7%) 

Hemorrhage 13 (26%) 12 (24%) 9 (19%) 15 (33%) 

Hyperplasia, histiocytic 1 (2%) 

Hyperplasia, lymphoid 1 (2%) 4 (8%) 2 (4%) 4 (9%) 

Spleen (49) (50) (49) (49) 

Angiectasis 1 (2%) 

Hematopoietic cell proliferation 21 (43%) 15 (30%) 19 (39%) 16 (33%) 

Hemorrhage 1 (2%) 

Hyperplasia, lymphoid 1 (2%) 1 (2%) 

Thymus (38) (39) (38) (35) 

Cyst 2 (5%) 2 (5%) 5 (13%) 4 (11%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

136 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE C3 

Summary of the Incidence of Nonneoplastic Lesions in Male Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Integumentary System 

Skin (50) (50) (49) (50) 

Cyst epithelial inclusion 1 (2%) 

Inflammation, chronic, focal 1 (2%) 

Artery, subcutaneous tissue, inflammation,

 chronic 1 (2%) 

Hair follicle, atrophy 2 (4%) 

Subcutaneous tissue, angiectasis, focal 1 (2%) 

Subcutaneous tissue, edema 2 (4%) 1 (2%) 3 (6%) 

Subcutaneous tissue, inflammation, chronic,

 focal 1 (2%) 

Musculoskeletal System 

Bone (50) (50) (50) (50) 

Fracture 1 (2%) 

Hyperostosis 1 (2%) 

Skeletal muscle (50) (50) (50) 

Hemorrhage, focal 1 (2%) 

Inflammation, suppurative 1 (2%) 

Nervous System 

Spinal cord (1) (2) (2) (4) 

Hemorrhage, focal 1 (50%) 1 (25%) 

Respiratory System 

Lung (50) (50) (50) (50) 

Hemorrhage 1 (2%) 2 (4%) 2 (4%) 

Hyperplasia, histiocytic 4 (8%) 2 (4%) 2 (4%) 1 (2%) 

Hyperplasia, lymphoid 1 (2%) 

Infiltration cellular, mixed cell 1 (2%) 

Inflammation, chronic 1 (2%) 

Thrombosis 1 (2%) 

Alveolar epithelium, hyperplasia 1 (2%) 2 (4%) 1 (2%) 

Bronchus, glands, cyst 1 (2%) 3 (6%) 

Mediastinum, hemorrhage 1 (2%) 

Nose (50) (50) (50) (50) 

Inflammation, suppurative 1 (2%) 1 (2%) 1 (2%) 2 (4%) 

Mucosa, polyp, inflammatory 2 (4%) 2 (4%) 

Mucosa, glands, dilatation, focal 25 (50%) 26 (52%) 24 (48%) 26 (52%) 

Nasolacrimal duct, cyst 1 (2%) 

Nasolacrimal duct, dilatation 1 (2%) 

Nasopharyngeal duct, hyperplasia, focal 1 (2%) 

Special Senses System 

Harderian gland (4) (4) (6) (8) 

Degeneration, cystic, focal 1 (13%) 

Hyperplasia, focal 1 (13%) 

Inflammation, chronic, focal 1 (25%) 1 (13%) 
 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 137 

TABLE C3 

Summary of the Incidence of Nonneoplastic Lesions in Male Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Urinary System 

Kidney (49) (50) (49) (49) 

Congestion 1 (2%) 1 (2%) 

Cyst 1 (2%) 

Infarct 2 (4%) 2 (4%) 

Metaplasia, focal, osseous 2 (4%) 4 (8%) 

Nephropathy 46 (94%) 49 (98%) 44 (90%) 46 (94%) 

Artery, inflammation, chronic 1 (2%) 

Pelvis, dilatation 1 (2%) 2 (4%) 3 (6%) 

Renal tubule, dilatation 1 (2%) 3 (6%) 2 (4%) 

Renal tubule, pigmentation 1 (2%) 2 (4%) 

Urethra (9) (15) (14) (16) 

Inflammation, chronic 2 (22%) 2 (13%) 6 (43%) 4 (25%) 
138 AZT and AZT/"-Interferon A/D, NTP TR 469 
139 

APPENDIX D
 

SUMMARY OF LESIONS IN FEMALE MICE
 

IN THE 2-YEAR SUBCUTANEOUS STUDY
 

OF "-INTERFERON A/D
 

TABLE D1	 Summary of the Incidence of Neoplasms in Female Mice 

in the 2-Year Subcutaneous Study of "-Interferon A/D ....................... 140
 

TABLE D2 Statistical Analysis of Primary Neoplasms in Female Mice 

in the 2-Year Subcutaneous Study of "-Interferon A/D ....................... 145
 

TABLE D3 Historical Incidence of Alveolar/bronchiolar Neoplasms 

in Untreated Feed Control Female B6C3F1 Mice ............................ 149
 

TABLE D4	 Summary of the Incidence of Nonneoplastic Lesions in Female Mice 

in the 2-Year Subcutaneous Study of "-Interferon A/D ....................... 150
 
 

 

 

 

 

 

 

 

140 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE D1 

Summary of the Incidence of Neoplasms in Female Mice in the 2-Year Subcutaneous Study of "-Interferon A/Da 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Disposition Summary 

Animals initially in study 50 50 50 50 

Early deaths 

Accidental death 1 

Moribund 13 11 13 9 

Natural deaths 12 8 5 15 

Survivors 

Terminal sacrifice 25 31 32 25 

Animals examined microscopically 50 50 50 50 

Alimentary System 

Gallbladder (45) (49) (50) (48) 

Intestine large, colon (47) (50) (50) 

Intestine large, cecum (48) (49) (50) (50) 

Liposarcoma, metastatic, mesentery 1 (2%) 

Intestine small, duodenum (47) (50) (49) 

Intestine small, jejunum (47) (48) (50) (49) 

Histiocytic sarcoma 1 (2%) 

Intestine small, ileum (47) (48) (50) (49) 

Histiocytic sarcoma 1 (2%) 

Liver (49) (50) (50) (50) 

Carcinoma, metastatic, harderian gland 1 (2%) 

Fibrosarcoma, metastatic, mesentery 1 (2%) 

Hemangioma 1 (2%) 

Hemangiosarcoma 1 (2%) 

Hemangiosarcoma, multiple 1 (2%) 1 (2%) 

Hepatocellular carcinoma 9 (18%) 12 (24%) 10 (20%) 10 (20%) 

Hepatocellular carcinoma, multiple 7 (14%) 6 (12%) 2 (4%) 3 (6%) 

Hepatocellular adenoma 12 (24%) 13 (26%) 16 (32%) 12 (24%) 

Hepatocellular adenoma, multiple 12 (24%) 9 (18%) 9 (18%) 10 (20%) 

Hepatocholangiocarcinoma 1 (2%) 

Histiocytic sarcoma 1 (2%) 1 (2%) 1 (2%) 1 (2%) 

Liposarcoma, metastatic, mesentery 1 (2%) 

Mast cell tumor malignant, metastatic,

 uncertain primary site 1 (2%) 

Plasma cell tumor malignant, metastatic,

 spleen 1 (2%) 

Mesentery (21) (16) (21) (18) 

Carcinoma, metastatic, harderian gland 1 (5%) 

Fibrosarcoma 1 (6%) 

Fibrosarcoma, metastatic, skin 1 (5%) 1 (6%) 

Fibrosarcoma, metastatic, tissue NOS 1 (5%) 

Hemangiosarcoma 1 (6%) 

Hepatocellular carcinoma, metastatic, liver 1 (5%) 

Histiocytic sarcoma 1 (5%) 1 (5%) 

Liposarcoma 1 (5%) 

Mast cell tumor malignant, metastatic,

 uncertain primary site 1 (6%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 141 

TABLE D1 

Summary of the Incidence of Neoplasms in Female Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Alimentary System (continued) 

Pancreas (48) (50) (50) (50) 

Fibrosarcoma, metastatic, skin 1 (2%) 

Fibrosarcoma, metastatic, tissue NOS 1 (2%) 

Liposarcoma, metastatic, mesentery 1 (2%) 

Mast cell tumor malignant, metastatic,

 uncertain primary site 1 (2%) 

Acinus, adenoma 1 (2%) 

Salivary glands (50) (49) (50) (48) 

Mast cell tumor malignant, metastatic,

 uncertain primary site 1 (2%) 

Stomach, forestomach (48) (46) (50) (50) 

Liposarcoma, metastatic, mesentery 1 (2%) 

Mast cell tumor malignant, metastatic,

 uncertain primary site 1 (2%) 

Squamous cell papilloma 2 (4%) 

Stomach, glandular (48) (46) (50) (50) 

Hepatocellular carcinoma, metastatic, liver 1 (2%) 

Liposarcoma, metastatic, mesentery 1 (2%) 

Mast cell tumor malignant, metastatic,

 uncertain primary site 1 (2%) 

Cardiovascular System 

Heart (50) (50) (50) (50) 

Carcinoma, metastatic, harderian gland 1 (2%) 

Endocrine System 

Adrenal cortex (50) (49) (49) (50) 

Adenoma 1 (2%) 

Hepatocellular carcinoma, metastatic, liver 1 (2%) 

Capsule, adenoma 1 (2%) 

Adrenal medulla (50) (49) (49) (50) 

Pheochromocytoma malignant 1 (2%) 1 (2%) 

Pheochromocytoma benign 1 (2%) 

Islets, pancreatic (48) (50) 

Adenoma 1 (2%) 

Pituitary gland (46) (43) (47) (44) 

Pars distalis, adenoma 11 (24%) 5 (12%) 8 (17%) 7 (16%) 

Pars intermedia, adenoma 1 (2%) 

Thyroid gland (50) (50) (50) (49) 

Carcinoma, metastatic, harderian gland 1 (2%) 

Follicular cell, adenoma 5 (10%) 4 (8%) 3 (6%) 2 (4%) 

General Body System 

Peritoneum (2) (1) 

Fibrosarcoma, metastatic, skin 1 (50%) 

Tissue NOS (1) (1) (2) 

Abdominal, fibrosarcoma 1 (100%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

142 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE D1 

Summary of the Incidence of Neoplasms in Female Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Genital System 

Clitoral gland (48) (49) (49) (47) 

Hemangioma 1 (2%) 

Ovary (46) (48) (48) (49) 

Carcinoma, metastatic, harderian gland 1 (2%) 

Cystadenoma 4 (9%) 1 (2%) 2 (4%) 

Granulosa cell tumor benign 1 (2%) 

Hemangiosarcoma 1 (2%) 

Histiocytic sarcoma 1 (2%) 

Liposarcoma, metastatic, mesentery 1 (2%) 

Teratoma benign 1 (2%) 1 (2%) 

Uterus (50) (50) (50) (50) 

Hemangioma 1 (2%) 

Histiocytic sarcoma 1 (2%) 1 (2%) 

Liposarcoma, metastatic, mesentery 1 (2%) 

Endometrium, polyp stromal 1 (2%) 2 (4%) 1 (2%) 

Endometrium, sarcoma stromal 1 (2%) 

Vagina (48) (46) (50) (47) 

Sarcoma 1 (2%) 

Squamous cell carcinoma 1 (2%) 

Hematopoietic System 

Bone marrow (50) (50) (50) (50) 

Plasma cell tumor malignant, metastatic,

 spleen 1 (2%) 

Lymph node (12) (11) (13) (9) 

Bronchial, alveolar/bronchiolar carcinoma,

 metastatic, lung 1 (8%) 

Iliac, histiocytic sarcoma 1 (8%) 1 (8%) 

Inguinal, mast cell tumor malignant,

 metastatic, uncertain primary site 1 (11%) 

Mediastinal, carcinoma, metastatic,

 harderian gland 1 (8%) 

Mediastinal, fibrosarcoma, metastatic,

 mesentery 1 (9%) 

Mediastinal, fibrosarcoma, metastatic, skin 1 (8%) 

Mediastinal, fibrosarcoma, metastatic,

 tissue NOS 1 (8%) 

Mediastinal, hepatocellular carcinoma,

 metastatic, liver 1 (8%) 

Mediastinal, liposarcoma, metastatic,

 mesentery 1 (8%) 

Pancreatic, histiocytic sarcoma 1 (8%) 

Renal, histiocytic sarcoma 1 (8%) 1 (11%) 

Renal, liposarcoma, metastatic, mesentery 1 (8%) 

Lymph node, mandibular (49) (48) (49) (47) 

Histiocytic sarcoma 1 (2%) 1 (2%) 

Mast cell tumor malignant, metastatic,

 uncertain primary site 1 (2%) 

Lymph node, mesenteric (45) (47) (50) (50) 

Histiocytic sarcoma 2 (4%) 1 (2%) 

Liposarcoma, metastatic, mesentery 1 (2%) 

Mast cell tumor malignant, metastatic,

 uncertain primary site 1 (2%) 
 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 143 

TABLE D1 

Summary of the Incidence of Neoplasms in Female Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Hematopoietic System (continued) 

Spleen (47) (49) (50) (50) 

Alveolar/bronchiolar carcinoma, metastatic,

 lung 1 (2%) 

Fibrosarcoma, metastatic, mesentery 1 (2%) 

Hemangiosarcoma 1 (2%) 2 (4%) 1 (2%) 

Histiocytic sarcoma 1 (2%) 1 (2%) 

Mast cell tumor malignant, metastatic,

 uncertain primary site 1 (2%) 

Plasma cell tumor malignant 1 (2%) 

Thymus (41) (39) (48) (48) 

Alveolar/bronchiolar carcinoma, metastatic,

 lung 1 (3%) 

Carcinoma, metastatic, harderian gland 1 (2%) 

Histiocytic sarcoma 1 (2%) 

Liposarcoma, metastatic, mesentery 1 (2%) 

Integumentary System 

Mammary gland (50) (48) (50) 

Carcinoma 1 (2%) 

Skin (50) (50) (50) (50) 

Basal cell carcinoma 1 (2%) 

Squamous cell papilloma 1 (2%) 

Subcutaneous tissue, carcinoma, metastatic,

 harderian gland 1 (2%) 

Subcutaneous tissue, fibroma 1 (2%) 

Subcutaneous tissue, fibrosarcoma 2 (4%) 1 (2%) 

Subcutaneous tissue, hemangiosarcoma 2 (4%) 2 (4%) 2 (4%) 

Subcutaneous tissue, mast cell tumor

 malignant, metastatic,

 uncertain primary site 1 (2%) 

Musculoskeletal System 

Bone (50) (50) (50) 

Osteosarcoma 1 (2%) 1 (2%) 

Skeletal muscle (50) (50) (50) (50) 

Carcinoma, metastatic, harderian gland 1 (2%) 

Fibrosarcoma, metastatic, mesentery 1 (2%) 

Fibrosarcoma, metastatic, skin 1 (2%) 

Fibrosarcoma, metastatic, tissue NOS 1 (2%) 

Liposarcoma, metastatic, mesentery 1 (2%) 

Nervous System 

Brain (50) (50) (49) (50) 

Spinal cord (2) (1) (2) (4) 
 

 

 

 

 

 

 

 

 

 

144 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE D1 

Summary of the Incidence of Neoplasms in Female Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Respiratory System 

Lung (50) (50) (50) (50) 

Alveolar/bronchiolar adenoma 3 (6%) 5 (10%) 4 (8%) 

Alveolar/bronchiolar carcinoma 2 (4%) 7 (14%) 4 (8%) 

Basal cell carcinoma, metastatic, skin 1 (2%) 

Carcinoma, metastatic, harderian gland 1 (2%) 

Hepatocellular carcinoma, metastatic, liver 2 (4%) 4 (8%) 2 (4%) 3 (6%) 

Histiocytic sarcoma 1 (2%) 1 (2%) 

Liposarcoma, metastatic, mesentery 1 (2%) 

Mast cell tumor malignant, metastatic,

 uncertain primary site 1 (2%) 

Osteosarcoma, metastatic, bone 1 (2%) 

Mediastinum, alveolar/bronchiolar carcinoma,

 metastatic, lung 1 (2%) 

Mediastinum, mast cell tumor malignant,

 metastatic, uncertain primary site 1 (2%) 

Nose (50) (50) (50) (50) 

Carcinoma, metastatic, harderian gland 1 (2%) 

Special Senses System 

Harderian gland (3) (3) (8) (4) 

Adenoma 2 (67%) 3 (100%) 5 (63%) 3 (75%) 

Carcinoma 1 (33%) 2 (25%) 

Urinary System 

Kidney (48) (50) (50) (49) 

Carcinoma, metastatic, harderian gland 1 (2%) 

Mast cell tumor malignant, metastatic,

 uncertain primary site 1 (2%) 

Ureter (1) 

Fibrosarcoma, metastatic, skin 1 (100%) 

Urinary bladder (50) (50) (50) (50) 

Systemic Lesions 

Multiple organsb (50) (50) (50) (50) 

Histiocytic sarcoma 2 (4%) 1 (2%) 1 (2%) 2 (4%) 

Lymphoma malignant 11 (22%) 6 (12%) 13 (26%) 11 (22%) 

Neoplasm Summary 

Total animals with primary neoplasmsc 48 44 48 44 

Total primary neoplasms 96 84 92 72 

Total animals with benign neoplasms 34 31 32 33 

Total benign neoplasms 53 43 52 42 

Total animals with malignant neoplasms 35 30 33 27 

Total malignant neoplasms 43 41 40 30 

Total animals with metastatic neoplasms 7 7 6 4 

Total metastatic neoplasms 36 12 12 17 

Total animals with malignant neoplasms

 of uncertain primary site 1 

a Number of animals examined microscopically at the site and the number of animals with neoplasm b Number of animals with any tissue examined microscopically 

Primary neoplasms: all neoplasms except metastatic neoplasms c 
AZT and AZT/"-Interferon A/D, NTP TR 469 145 

TABLE D2 

Statistical Analysis of Primary Neoplasms in Female Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Harderian Gland: Adenoma 

Overall ratea 

Adjusted rateb 2/50 (4%) 

8.0% 

3/50 (6%) 

8.9% 

5/50 (10%) 

15.6% 

3/50 (6%) 

10.9% 

Terminal ratec 2/25 (8%) 2/31 (6%) 5/32 (16%) 2/25 (8%) 

First incidence (days) 

Life table testd 729 (T) 

P=0.611 

642 

P=0.567 

729 (T) 

P=0.323 

672 

P=0.487 

Logistic regression testd 

Cochran-Armitage testd 

Fisher exact testd 

P=0.597 

P=0.582N 

P=0.503 

P=0.500 

P=0.323 

P=0.218 

P=0.467 

P=0.500 

Harderian Gland: Adenoma or Carcinoma 

Overall rate 3/50 (6%) 3/50 (6%) 7/50 (14%) 3/50 (6%) 

Adjusted rate 10.8% 8.9% 20.5% 10.9% 

Terminal rate 2/25 (8%) 2/31 (6%) 6/32 (19%) 2/25 (8%) 

First incidence (days) 681 642 610 672 

Life table test P=0.424N P=0.595N P=0.266 P=0.643 

Logistic regression test P=0.414N P=0.661 P=0.195 P=0.632 

Cochran-Armitage test P=0.345N 

Fisher exact test P=0.661N P=0.159 P=0.661N 

Liver: Hepatocellular Adenoma 

Overall rate 24/49 (49%) 22/50 (44%) 25/50 (50%) 22/50 (44%) 

Adjusted rate 73.8% 59.2% 65.1% 63.0% 

Terminal rate 17/25 (68%) 16/31 (52%) 19/32 (59%) 13/25 (52%) 

First incidence (days) 597 575 553 506 

Life table test P=0.533 P=0.168N P=0.249N P=0.476N 

Logistic regression test P=0.510N P=0.394N P=0.456N P=0.492N 

Cochran-Armitage test P=0.323N 

Fisher exact test P=0.384N P=0.540 P=0.384N 

Liver: Hepatocellular Carcinoma 

Overall rate 16/49 (33%) 18/50 (36%) 12/50 (24%) 13/50 (26%) 

Adjusted rate 42.9% 47.5% 34.8% 43.8% 

Terminal rate 7/25 (28%) 12/31 (39%) 10/32 (31%) 9/25 (36%) 

First incidence (days) 533 563 645 581 

Life table test P=0.546 P=0.564 P=0.121N P=0.384N 

Logistic regression test P=0.524N P=0.431 P=0.212N P=0.360N 

Cochran-Armitage test P=0.422N 

Fisher exact test P=0.445 P=0.232N P=0.306N 

Liver: Hepatocellular Adenoma or Carcinoma 

Overall rate 33/49 (67%) 34/50 (68%) 31/50 (62%) 29/50 (58%) 

Adjusted rate 86.1% 82.8% 77.1% 75.7% 

Terminal rate 20/25 (80%) 24/31 (77%) 23/32 (72%) 16/25 (64%) 

First incidence (days) 533 563 553 506 

Life table test P=0.517 P=0.293N P=0.082N P=0.376N 

Logistic regression test P=0.452N P=0.478 P=0.221N P=0.328N 

Cochran-Armitage test P=0.252N 

Fisher exact test P=0.558 P=0.365N P=0.226N 
146 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE D2 

Statistical Analysis of Primary Neoplasms in Female Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Lung: Alveolar/bronchiolar Adenoma 

Overall rate 0/50 (0%) 3/50 (6%) 5/50 (10%) 4/50 (8%) 

Adjusted rate 0.0% 7.8% 14.4% 14.0% 

Terminal rate 0/25 (0%) 1/31 (3%) 3/32 (9%) 3/25 (12%) 

First incidence (days) —e 601 698 581 

Life table test P=0.227 P=0.128 P=0.061 P=0.062 

Logistic regression test P=0.234 P=0.127 P=0.047 P=0.057 

Cochran-Armitage test P=0.283 

Fisher exact test P=0.121 P=0.028 P=0.059 

Lung: Alveolar/bronchiolar Carcinoma 

Overall rate 2/50 (4%) 7/50 (14%) 4/50 (8%) 0/50 (0%) 

Adjusted rate 7.3% 19.2% 10.3% 0.0% 

Terminal rate 1/25 (4%) 3/31 (10%) 2/32 (6%) 0/25 (0%) 

First incidence (days) 708 612 483 — 

Life table test P=0.130N P=0.133 P=0.437 P=0.248N 

Logistic regression test P=0.100N P=0.078 P=0.302 P=0.253N 

Cochran-Armitage test P=0.105N 

Fisher exact test P=0.080 P=0.339 P=0.247N 

Lung: Alveolar/bronchiolar Adenoma or Carcinoma 

Overall rate 2/50 (4%) 9/50 (18%) 9/50 (18%) 4/50 (8%) 

Adjusted rate 7.3% 23.9% 23.8% 14.0% 

Terminal rate 1/25 (4%) 4/31 (13%) 5/32 (16%) 3/25 (12%) 

First incidence (days) 708 601 483 581 

Life table test P=0.552N P=0.054 P=0.069 P=0.330 

Logistic regression test P=0.505N P=0.026 P=0.028 P=0.311 

Cochran-Armitage test P=0.464N 

Fisher exact test P=0.026 P=0.026 P=0.339 

Ovary: Cystadenoma 

Overall rate 4/46 (9%) 1/48 (2%) 2/48 (4%) 0/49 (0%) 

Adjusted rate 16.1% 3.4% 4.8% 0.0% 

Terminal rate 3/22 (14%) 1/29 (3%) 0/32 (0%) 0/25 (0%) 

First incidence (days) 675 729 (T) 685 — 

Life table test P=0.093N P=0.117N P=0.213N P=0.055N 

Logistic regression test P=0.078N P=0.153N P=0.290N P=0.060N 

Cochran-Armitage test P=0.069N 

Fisher exact test P=0.168N P=0.318N P=0.051N 

Pituitary Gland (Pars Distalis): Adenoma 

Overall rate 11/46 (24%) 5/43 (12%) 8/47 (17%) 7/44 (16%) 

Adjusted rate 38.9% 16.7% 23.9% 31.8% 

Terminal rate 9/25 (36%) 4/27 (15%) 5/29 (17%) 7/22 (32%) 

First incidence (days) 638 563 687 729 (T) 

Life table test P=0.436N P=0.069N P=0.193N P=0.300N 

Logistic regression test P=0.464N P=0.131N P=0.226N P=0.338N 

Cochran-Armitage test P=0.314N 

Fisher exact test P=0.108N P=0.286N P=0.247N 
 

AZT and AZT/"-Interferon A/D, NTP TR 469 147 

TABLE D2 

Statistical Analysis of Primary Neoplasms in Female Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Thyroid Gland (Follicular Cell): Adenoma 

Overall rate 5/50 (10%) 4/50 (8%) 3/50 (6%) 2/49 (4%) 

Adjusted rate 18.0% 12.9% 9.4% 8.0% 

Terminal rate 4/25 (16%) 4/31 (13%) 3/32 (9%) 2/25 (8%) 

First incidence (days) 654 729 (T) 729 (T) 729 (T) 

Life table test P=0.302N P=0.387N P=0.239N P=0.220N 

Logistic regression test P=0.320N P=0.463N P=0.278N P=0.247N 

Cochran-Armitage test P=0.262N 

Fisher exact test P=0.500N P=0.357N P=0.226N 

All Organs: Hemangiosarcoma 

Overall rate 2/50 (4%) 5/50 (10%) 3/50 (6%) 1/50 (2%) 

Adjusted rate 6.5% 15.0% 8.8% 3.0% 

Terminal rate 1/25 (4%) 4/31 (13%) 2/32 (6%) 0/25 (0%) 

First incidence (days) 671 612 701 667 

Life table test P=0.403N P=0.276 P=0.595 P=0.542N 

Logistic regression test P=0.371N P=0.212 P=0.540 P=0.514N 

Cochran-Armitage test P=0.338N 

Fisher exact test P=0.218 P=0.500 P=0.500N 

All Organs: Hemangioma or Hemangiosarcoma 

Overall rate 3/50 (6%) 6/50 (12%) 3/50 (6%) 2/50 (4%) 

Adjusted rate 10.4% 18.2% 8.8% 6.9% 

Terminal rate 2/25 (8%) 5/31 (16%) 2/32 (6%) 1/25 (4%) 

First incidence (days) 671 612 701 667 

Life table test P=0.518N P=0.323 P=0.558N P=0.533N 

Logistic regression test P=0.496N P=0.240 P=0.615N P=0.528N 

Cochran-Armitage test P=0.441N 

Fisher exact test P=0.243 P=0.661N P=0.500N 

All Organs: Malignant Lymphoma 

Overall rate 11/50 (22%) 6/50 (12%) 13/50 (26%) 11/50 (22%) 

Adjusted rate 32.8% 15.5% 33.3% 33.9% 

Terminal rate 5/25 (20%) 3/31 (10%) 8/32 (25%) 6/25 (24%) 

First incidence (days) 597 449 623 567 

Life table test P=0.511 P=0.108N P=0.552N P=0.547 

Logistic regression test P=0.548N P=0.138N P=0.428 P=0.555 

Cochran-Armitage test P=0.486N 

Fisher exact test P=0.143N P=0.408 P=0.595N 

All Organs: Benign Neoplasms 

Overall rate 34/50 (68%) 31/50 (62%) 32/50 (64%) 33/50 (66%) 

Adjusted rate 94.1% 73.7% 77.7% 88.5% 

Terminal rate 23/25 (92%) 20/31 (65%) 23/32 (72%) 21/25 (84%) 

First incidence (days) 597 563 553 293 

Life table test P=0.262 P=0.111N P=0.064N P=0.572N 

Logistic regression test P=0.350 P=0.394N P=0.211N P=0.530 

Cochran-Armitage test P=0.553N 

Fisher exact test P=0.338N P=0.417N P=0.500N 
148 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE D2 

Statistical Analysis of Primary Neoplasms in Female Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

All Organs: Malignant Neoplasms 

Overall rate 35/50 (70%) 30/50 (60%) 33/50 (66%) 28/50 (56%) 

Adjusted rate 73.6% 66.0% 71.2% 72.1% 

Terminal rate 13/25 (52%) 16/31 (52%) 19/32 (59%) 15/25 (60%) 

First incidence (days) 409 426 483 506 

Life table test P=0.389N P=0.155N P=0.153N P=0.260N 

Logistic regression test P=0.107N P=0.299N P=0.546N P=0.133N 

Cochran-Armitage test P=0.096N 

Fisher exact test P=0.201N P=0.415N P=0.107N 

All Organs: Benign or Malignant Neoplasms 

Overall rate 48/50 (96%) 44/50 (88%) 48/50 (96%) 44/50 (88%) 

Adjusted rate 98.0% 93.6% 96.0% 97.7% 

Terminal rate 24/25 (96%) 28/31 (90%) 30/32 (94%) 24/25 (96%) 

First incidence (days) 409 426 483 293 

Life table test P=0.445 P=0.086N P=0.101N P=0.433N 

Logistic regression test P=0.238N P=0.185N P=0.610N P=0.296N 

Cochran-Armitage test P=0.065N 

Fisher exact test P=0.134N P=0.691N P=0.134N 

(T)Terminal sacrifice 

a Number of neoplasm-bearing animals/number of animals examined. Denominator is number of animals examined microscopically for liver, lung, ovary, 

pituitary gland, and thyroid gland; for other tissues, denominator is number of animals necropsied. b	 Kaplan-Meier estimated neoplasm incidence at the end of the study after adjustment for intercurrent mortality 

Observed incidence at terminal kill 

d	 Beneath the vehicle control incidence are the P values associated with the trend test (the "-IFN A group was excluded from the trend test). Beneath the dosed 

group incidence are the P values corresponding to pairwise comparisons between the vehicle controls and that dosed group. The life table test regards 

neoplasms in animals dying prior to terminal kill as being (directly or indirectly) the cause of death. The logistic regression test regards these lesions as 

nonfatal. The Cochran-Armitage and Fisher exact tests compare directly the overall incidence rates. For all tests, a negative trend or a lower incidence in a 

dosed group is indicated by N. e Not applicable; no neoplasms in animal group 
AZT and AZT/"-Interferon A/D, NTP TR 469 149 

TABLE D3 

Historical Incidence of Alveolar/bronchiolar Neoplasms in Untreated Feed Control Female B6C3F a 1 Mice

Incidence in Controls 

Adenoma Carcinoma Adenoma 

or Carcinoma 

Overall Historical Incidence 

Total 85/1,472 (5.8%) 31/1,472 (2.1%) 114/1,472 (7.7%) 

Standard deviation 4.8% 2.3% 5.1% 

Range 0%-24% 0%-8% 2%-26% 

a Data as of 12 May 1995 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

150 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE D4 

Summary of the Incidence of Nonneoplastic Lesions in Female Mice in the 2-Year Subcutaneous Study 

of "-Interferon A/Da 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Disposition Summary 

Animals initially in study 50 50 50 50 

Early deaths 

Accidental death 1 

Moribund 13 11 13 9 

Natural deaths 12 8 5 15 

Survivors 

Terminal sacrifice 25 31 32 25 

Animals examined microscopically 50 50 50 50 

Alimentary System 

Intestine large, rectum (47) (49) (50) (50) 

Artery, inflammation, chronic 1 (2%) 

Intestine small, jejunum (47) (48) (50) (49) 

Peyer’s patch, hyperplasia, lymphoid 1 (2%) 

Liver (49) (50) (50) (50) 

Angiectasis 1 (2%) 3 (6%) 2 (4%) 

Basophilic focus 1 (2%) 3 (6%) 

Clear cell focus 1 (2%) 1 (2%) 1 (2%) 

Congestion 1 (2%) 

Eosinophilic focus 1 (2%) 8 (16%) 8 (16%) 8 (16%) 

Fibrosis, focal 1 (2%) 

Hematopoietic cell proliferation 1 (2%) 1 (2%) 3 (6%) 

Hyperplasia, focal, lymphoid 1 (2%) 

Inflammation, chronic 4 (8%) 9 (18%) 6 (12%) 10 (20%) 

Mixed cell focus 4 (8%) 1 (2%) 4 (8%) 

Necrosis, focal 3 (6%) 3 (6%) 5 (10%) 5 (10%) 

Pigmentation, focal 2 (4%) 1 (2%) 2 (4%) 1 (2%) 

Vacuolization cytoplasmic 5 (10%) 3 (6%) 2 (4%) 3 (6%) 

Artery, inflammation, chronic 1 (2%) 

Bile duct, cyst 1 (2%) 1 (2%) 

Bile duct, hyperplasia 1 (2%) 1 (2%) 

Hepatocyte, karyomegaly 2 (4%) 1 (2%) 1 (2%) 

Mesentery (21) (16) (21) (18) 

Accessory spleen 1 (5%) 

Angiectasis 1 (5%) 

Artery, inflammation, chronic 1 (5%) 2 (13%) 

Fibrosis, focal 1 (6%) 

Infiltration cellular, mixed cell 1 (6%) 

Inflammation, chronic 1 (5%) 3 (17%) 

Fat, necrosis 13 (62%) 10 (63%) 12 (57%) 12 (67%) 

Pancreas (48) (50) (50) 

Inflammation, chronic 1 (2%) 

Necrosis, focal 1 (2%) 

Acinus, atrophy, diffuse 2 (4%) 

Acinus, atrophy, focal 1 (2%) 1 (2%) 

Duct, cyst 3 (6%) 

Salivary glands (50) (49) 

Inflammation, chronic 1 (2%) 

a Number of animals examined microscopically at the site and the number of animals with lesion 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 151 

TABLE D4 

Summary of the Incidence of Nonneoplastic Lesions in Female Mice in the 2-Year Subcutaneous Study 

of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Alimentary System (continued) 

Stomach, forestomach (48) (46) (50) (50) 

Diverticulum 2 (4%) 

Edema 1 (2%) 

Erosion 5 (10%) 1 (2%) 3 (6%) 

Inflammation, chronic 3 (6%) 3 (7%) 3 (6%) 

Epithelium, cyst 1 (2%) 

Epithelium, hyperplasia 7 (15%) 4 (9%) 4 (8%) 

Stomach, glandular (48) (46) (50) (50) 

Erosion 1 (2%) 1 (2%) 1 (2%) 1 (2%) 

Mineralization 1 (2%) 

Pigmentation, focal 1 (2%) 2 (4%) 2 (4%) 

Artery, inflammation, chronic 1 (2%) 

Glands, degeneration, cystic, focal 1 (2%) 1 (2%) 

Cardiovascular System 

Blood vessel (50) (49) (50) (50) 

Inflammation, chronic 1 (2%) 

Pulmonary vein, intima, mineralization, focal 1 (2%) 

Heart (50) (50) (50) (50) 

Inflammation, chronic, focal 1 (2%) 1 (2%) 

Thrombosis 1 (2%) 

Artery, inflammation, chronic 1 (2%) 1 (2%) 

Endocrine System 

Adrenal cortex (50) (49) (49) (50) 

Accessory adrenal cortical nodule 3 (6%) 1 (2%) 

Cyst 1 (2%) 

Cytoplasmic alteration, focal 1 (2%) 

Hyperplasia 1 (2%) 

Hypertrophy, focal 1 (2%) 

Capsule, hyperplasia, focal 1 (2%) 2 (4%) 2 (4%) 1 (2%) 

Islets, pancreatic (48) (50) (50) 

Hyperplasia 1 (2%) 

Adrenal medulla (50) (49) 

Hyperplasia 2 (4%) 

Parathyroid gland (44) (47) (46) (46) 

Cyst 1 (2%) 1 (2%) 

Pituitary gland (46) (43) (47) (44) 

Angiectasis 1 (2%) 3 (7%) 3 (6%) 1 (2%) 

Pars distalis, cytoplasmic alteration, focal 1 (2%) 2 (5%) 3 (6%) 4 (9%) 

Pars distalis, hyperplasia, focal 1 (2%) 1 (2%) 2 (4%) 1 (2%) 

Thyroid gland (50) (50) (50) (49) 

Angiectasis 1 (2%) 

Degeneration, cystic, focal 8 (16%) 8 (16%) 9 (18%) 10 (20%) 

Inflammation, chronic, focal 1 (2%) 2 (4%) 1 (2%) 

C-cell, hyperplasia 1 (2%) 1 (2%) 

Follicle, cyst 2 (4%) 1 (2%) 1 (2%) 

Follicular cell, hyperplasia 17 (34%) 14 (28%) 21 (42%) 18 (37%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

152 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE D4 

Summary of the Incidence of Nonneoplastic Lesions in Female Mice in the 2-Year Subcutaneous Study 

of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

General Body System 

Peritoneum (2) (1) 

Infiltration cellular, histiocyte 1 (50%) 

Infiltration cellular, mixed cell 1 (100%) 

Tissue NOS (1) (1) (2) 

Hemorrhage 1 (50%) 

Genital System 

Clitoral gland (48) (49) (49) (47) 

Degeneration, cystic 3 (6%) 6 (12%) 3 (6%) 2 (4%) 

Ovary (46) (48) (48) (49) 

Angiectasis 3 (6%) 2 (4%) 

Atrophy 1 (2%) 

Cyst 10 (22%) 8 (17%) 11 (23%) 7 (14%) 

Inflammation, suppurative 1 (2%) 

Thrombosis 1 (2%) 

Bilateral, cyst 1 (2%) 1 (2%) 2 (4%) 

Oviduct (1) 

Inflammation, suppurative 1 (100%) 

Uterus (50) (50) (50) (50) 

Angiectasis 1 (2%) 

Hydrometra 10 (20%) 20 (40%) 11 (22%) 11 (22%) 

Inflammation, suppurative 1 (2%) 1 (2%) 2 (4%) 1 (2%) 

Thrombosis 1 (2%) 

Endometrium, hyperplasia, cystic 48 (96%) 48 (96%) 49 (98%) 46 (92%) 

Vagina (48) (46) (50) (47) 

Inflammation, chronic 1 (2%) 

Inflammation, focal, granulomatous 1 (2%) 

Epithelium, hyperplasia 1 (2%) 

Hematopoietic System 

Bone marrow (50) (50) (50) (50) 

Depletion cellular 1 (2%) 

Hyperplasia 2 (4%) 2 (4%) 

Lymph node (12) (11) (13) (9) 

Iliac, hemorrhage 1 (8%) 

Iliac, hyperplasia 1 (9%) 

Iliac, hyperplasia, lymphoid 1 (8%) 

Inguinal, hyperplasia 2 (17%) 

Inguinal, hyperplasia, lymphoid 1 (9%) 1 (11%) 

Mediastinal, hyperplasia 1 (9%) 1 (8%) 2 (22%) 

Mediastinal, hyperplasia, lymphoid 1 (8%) 2 (15%) 1 (11%) 

Mediastinal, inflammation, focal, suppurative 1 (9%) 1 (11%) 

Pancreatic, hyperplasia, lymphoid 1 (8%) 

Renal, hemorrhage 1 (8%) 

Renal, hyperplasia, lymphoid 1 (9%) 1 (8%) 

Lymph node, mandibular (49) (48) (49) (47) 

Hemorrhage 1 (2%) 

Hyperplasia 1 (2%) 1 (2%) 

Hyperplasia, lymphoid 1 (2%) 2 (4%) 2 (4%) 1 (2%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 153 

TABLE D4 

Summary of the Incidence of Nonneoplastic Lesions in Female Mice in the 2-Year Subcutaneous Study 

of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Hematopoietic System (continued) 

Lymph node, mesenteric (45) (47) (50) (50) 

Angiectasis 1 (2%) 1 (2%) 

Ectasia 1 (2%) 2 (4%) 

Hematopoietic cell proliferation 1 (2%) 

Hemorrhage 2 (4%) 2 (4%) 1 (2%) 

Hyperplasia 2 (4%) 

Hyperplasia, histiocytic 1 (2%) 

Hyperplasia, lymphoid 3 (7%) 2 (4%) 4 (8%) 3 (6%) 

Inflammation, focal, suppurative 1 (2%) 

Pigmentation 1 (2%) 

Spleen (47) (49) (50) (50) 

Hematopoietic cell proliferation 21 (45%) 20 (41%) 24 (48%) 26 (52%) 

Hyperplasia, histiocytic 1 (2%) 

Hyperplasia, lymphoid 3 (6%) 5 (10%) 4 (8%) 2 (4%) 

Necrosis, focal 1 (2%) 

Thymus (41) (39) (48) (48) 

Cyst 1 (2%) 2 (4%) 2 (4%) 

Hyperplasia, histiocytic 1 (3%) 

Hyperplasia, lymphoid 1 (2%) 1 (2%) 

Epithelial cell, hyperplasia 1 (2%) 

Integumentary System 

Mammary gland (50) (50) (48) (50) 

Ectasia 1 (2%) 2 (4%) 1 (2%) 

Hyperplasia 1 (2%) 1 (2%) 1 (2%) 

Skin (50) (50) (50) (50) 

Cyst epithelial inclusion 1 (2%) 

Inflammation, chronic, focal 1 (2%) 

Ulcer 1 (2%) 

Artery, subcutaneous tissue, inflammation,

 chronic 1 (2%) 

Subcutaneous tissue, edema 1 (2%) 2 (4%) 

Subcutaneous tissue, hemorrhage, focal 1 (2%) 

Subcutaneous tissue, inflammation, chronic,

 focal 1 (2%) 1 (2%) 

Musculoskeletal System 

Bone (50) (50) (50) (50) 

Fibrous osteodystrophy 1 (2%) 

Osteoporosis 1 (2%) 

Nervous System 

Brain (50) (50) (49) (50) 

Atrophy, focal 2 (4%) 1 (2%) 2 (4%) 1 (2%) 

Hemorrhage, focal 1 (2%) 

Spinal cord (2) (2) (4) 

Hemorrhage, focal 1 (25%) 

Meninges, inflammation, focal 1 (25%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

154 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE D4 

Summary of the Incidence of Nonneoplastic Lesions in Female Mice in the 2-Year Subcutaneous Study 

of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Respiratory System 

Lung (50) (50) (50) (50) 

Hemorrhage 2 (4%) 1 (2%) 2 (4%) 2 (4%) 

Hyperplasia, histiocytic 4 (8%) 3 (6%) 2 (4%) 1 (2%) 

Hyperplasia, lymphoid 1 (2%) 1 (2%) 

Infiltration cellular, mixed cell 1 (2%) 

Pigmentation, focal 1 (2%) 

Alveolar epithelium, hyperplasia 2 (4%) 1 (2%) 1 (2%) 2 (4%) 

Bronchus, glands, cyst 1 (2%) 

Mediastinum, infiltration cellular, mixed

 cell 1 (2%) 

Mediastinum, inflammation, chronic 1 (2%) 1 (2%) 

Mediastinum, necrosis, focal 1 (2%) 

Nose (50) (50) (50) (50) 

Inflammation, suppurative 1 (2%) 

Mucosa, glands, dilatation, focal 41 (82%) 40 (80%) 42 (84%) 41 (82%) 

Nasolacrimal duct, cyst 1 (2%) 

Special Senses System 

Eye (1) (3) 

Atrophy 1 (33%) 

Inflammation, chronic 1 (33%) 

Anterior chamber, infiltration cellular,

 polymorphonuclear 1 (33%) 

Cornea, inflammation, chronic 1 (100%) 2 (67%) 

Cornea, necrosis, focal 1 (33%) 

Harderian gland (3) (8) (4) 

Hyperplasia, focal 1 (13%) 1 (25%) 

Urinary System 

Kidney (48) (50) (50) (49) 

Cyst 1 (2%) 1 (2%) 

Metaplasia, focal, osseous 3 (6%) 1 (2%) 2 (4%) 

Nephropathy 29 (60%) 31 (62%) 38 (76%) 31 (63%) 

Artery, inflammation, chronic 1 (2%) 

Pelvis, dilatation 2 (4%) 1 (2%) 

Renal tubule, accumulation, hyaline droplet 2 (4%) 3 (6%) 1 (2%) 

Renal tubule, dilatation 2 (4%) 3 (6%) 

Renal tubule, hyperplasia, focal 1 (2%) 

Renal tubule, necrosis 1 (2%) 1 (2%) 

Renal tubule, pigmentation 2 (4%) 2 (4%) 

Urethra (1) (1) 

Inflammation, chronic 1 (100%) 

Artery, inflammation, chronic 1 (100%) 

Urinary bladder (50) (50) (50) (50) 

Artery, inflammation, chronic 1 (2%) 
155 

APPENDIX E 

SUMMARY OF LESIONS IN MALE MICE 

IN THE 2-YEAR GAVAGE STUDY 

OF AZT/500 U "-INTERFERON A/D 

TABLE E1 Summary of the Incidence of Neoplasms in Male Mice 

in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D ................... 156 

TABLE E2 Statistical Analysis of Primary Neoplasms in Male Mice 

in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D ................... 160 

TABLE E3 Summary of the Incidence of Nonneoplastic Lesions in Male Mice 

in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D ................... 164 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

156 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE E1 

Summary of the Incidence of Neoplasms in Male Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/Da 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Disposition Summary 

Animals initially in study 50 50 50 50 

Early deaths 

Accidental deaths 2 3 

Moribund 13 14 5 9 

Natural deaths 1 7 4 6 

Survivors 

Terminal sacrifice 36 27 38 35 

Animals examined microscopically 50 50 50 50 

Alimentary System 

Esophagus (50) (50) (50) (50) 

Squamous cell papilloma 1 (2%) 

Intestine small, jejunum (50) (50) (48) (50) 

Carcinoma 1 (2%) 

Fibrous histiocytoma, metastatic,

 lymph node, mesenteric 1 (2%) 

Intestine small, ileum (50) (48) (49) (50) 

Liver (50) (50) (50) (50) 

Carcinoid tumor malignant, metastatic,

 uncertain primary site 1 (2%) 

Cholangiocarcinoma 1 (2%) 

Fibrous histiocytoma, metastatic,

 lymph node, mesenteric 1 (2%) 

Hemangiosarcoma 1 (2%) 2 (4%) 1 (2%) 1 (2%) 

Hemangiosarcoma, multiple 2 (4%) 3 (6%) 3 (6%) 3 (6%) 

Hepatoblastoma 1 (2%) 1 (2%) 1 (2%) 

Hepatocellular carcinoma 12 (24%) 13 (26%) 15 (30%) 9 (18%) 

Hepatocellular carcinoma, multiple 1 (2%) 7 (14%) 2 (4%) 5 (10%) 

Hepatocellular adenoma 10 (20%) 12 (24%) 14 (28%) 14 (28%) 

Hepatocellular adenoma, multiple 6 (12%) 4 (8%) 5 (10%) 4 (8%) 

Histiocytic sarcoma 2 (4%) 1 (2%) 

Ito cell tumor benign 1 (2%) 

Sarcoma, metastatic, mesentery 1 (2%) 

Sarcoma, metastatic, skeletal muscle 1 (2%) 

Mesentery (1) (2) (1) 

Cholangiocarcinoma, metastatic, liver 1 (50%) 

Sarcoma 1 (50%) 

Pancreas (50) (50) (50) (50) 

Cholangiocarcinoma, metastatic, liver 1 (2%) 

Histiocytic sarcoma 1 (2%) 

Sarcoma, metastatic, mesentery 1 (2%) 

Sarcoma, metastatic, skeletal muscle 1 (2%) 

Salivary glands (50) (50) (50) (50) 

Stomach, forestomach (50) (50) (50) (50) 

Sarcoma, metastatic, mesentery 1 (2%) 

Sarcoma, metastatic, skeletal muscle 1 (2%) 

Squamous cell papilloma 1 (2%) 2 (4%) 

Stomach, glandular (50) (50) (50) (50) 

Carcinoma 1 (2%) 

Hepatocellular carcinoma, metastatic, liver 1 (2%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 157 

TABLE E1 

Summary of the Incidence of Neoplasms in Male Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Cardiovascular System 

Heart (50) (50) (50) (50) 

Carcinoid tumor malignant, metastatic,

 uncertain primary site 1 (2%) 

Cholangiocarcinoma, metastatic, liver 1 (2%) 

Endocrine System 

Adrenal cortex (50) (50) (50) (50) 

Adenoma 1 (2%) 

Sarcoma, metastatic, skeletal muscle 1 (2%) 

Bilateral, capsule, adenoma 1 (2%) 

Capsule, adenoma 2 (4%) 

Adrenal medulla (50) (50) (50) (50) 

Pheochromocytoma malignant 1 (2%) 

Islets, pancreatic (50) (50) (50) (50) 

Adenoma 1 (2%) 

Pituitary gland (48) (43) (48) (47) 

Pars distalis, adenoma 1 (2%) 

Pars intermedia, adenoma 1 (2%) 

Pars intermedia, carcinoma 1 (2%) 

Thyroid gland (50) (50) (50) (49) 

Bilateral, follicular cell, adenoma 1 (2%) 

Follicular cell, adenoma 3 (6%) 2 (4%) 1 (2%) 

General Body System 

None 

Genital System 

Epididymis (50) (50) (50) (50) 

Hemangiosarcoma 1 (2%) 

Hepatocellular carcinoma, metastatic, liver 1 (2%) 

Histiocytic sarcoma 1 (2%) 

Preputial gland (48) (48) (50) (50) 

Carcinoma 1 (2%) 

Prostate (50) (50) (48) (50) 

Testes (50) (50) (50) (50) 

Histiocytic sarcoma 1 (2%) 

Interstitial cell, adenoma 1 (2%) 

Hematopoietic System 

Bone marrow (50) (50) (50) (50) 

Hemangiosarcoma 1 (2%) 1 (2%) 

Lymph node (5) (8) (5) (5) 

Iliac, histiocytic sarcoma 1 (20%) 

Inguinal, histiocytic sarcoma 1 (20%) 

Pancreatic, fibrous histiocytoma, metastatic,

 lymph node, mesenteric 1 (13%) 

Pancreatic, sarcoma, metastatic,

 skeletal muscle 1 (13%) 

Renal, fibrous histiocytoma, metastatic,

 lymph node, mesenteric 1 (20%) 

Renal, histiocytic sarcoma 1 (20%) 1 (13%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

158 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE E1 

Summary of the Incidence of Neoplasms in Male Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Hematopoietic System (continued) 

Lymph node, mandibular (46) (47) (49) (46) 

Carcinoma, metastatic, harderian gland 1 (2%) 

Lymph node, mesenteric (50) (48) (50) (47) 

Fibrous histiocytoma 1 (2%) 1 (2%) 

Hemangiosarcoma 1 (2%) 

Histiocytic sarcoma 2 (4%) 1 (2%) 

Sarcoma, metastatic, mesentery 1 (2%) 

Sarcoma, metastatic, skeletal muscle 1 (2%) 

Spleen (50) (49) (49) (50) 

Fibrous histiocytoma, metastatic,

 lymph node, mesenteric 1 (2%) 

Hemangiosarcoma 1 (2%) 1 (2%) 1 (2%) 

Histiocytic sarcoma 1 (2%) 

Thymus (45) (40) (42) (43) 

Fibrosarcoma 1 (2%) 

Fibrous histiocytoma, metastatic,

 lymph node, mesenteric 1 (2%) 

Histiocytic sarcoma 1 (2%) 1 (3%) 

Integumentary System 

Skin (50) (50) (50) (50) 

Subcutaneous tissue, fibrosarcoma 1 (2%) 1 (2%) 

Subcutaneous tissue, hemangiosarcoma 1 (2%) 

Subcutaneous tissue, sarcoma 1 (2%) 

Musculoskeletal System 

Bone (50) (50) (50) (50) 

Alveolar/bronchiolar carcinoma, metastatic,

 lung 1 (2%) 

Skeletal muscle (50) (50) (50) (50) 

Cholangiocarcinoma, metastatic, liver 1 (2%) 

Sarcoma 1 (2%) 

Nervous System 

None 

Respiratory System 

Lung (49) (50) (50) (50) 

Alveolar/bronchiolar adenoma 7 (14%) 3 (6%) 7 (14%) 7 (14%) 

Alveolar/bronchiolar adenoma, multiple 3 (6%) 1 (2%) 2 (4%) 1 (2%) 

Alveolar/bronchiolar carcinoma 4 (8%) 2 (4%) 6 (12%) 6 (12%) 

Alveolar/bronchiolar carcinoma, multiple 2 (4%) 1 (2%) 

Carcinoid tumor malignant, metastatic,

 uncertain primary site 1 (2%) 

Carcinoma, metastatic, harderian gland 1 (2%) 

Cholangiocarcinoma, metastatic, liver 1 (2%) 

Fibrous histiocytoma, metastatic,

 lymph node, mesenteric 1 (2%) 

Hepatocellular carcinoma, metastatic, liver 3 (6%) 3 (6%) 2 (4%) 3 (6%) 

Histiocytic sarcoma 1 (2%) 1 (2%) 

Sarcoma, metastatic, skeletal muscle 1 (2%) 
 

 

159 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE E1 

Summary of the Incidence of Neoplasms in Male Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Special Senses System 

Harderian gland (3) (3) (1) (5) 

Adenoma 3 (100%) 3 (100%) 1 (100%) 2 (40%) 

Carcinoma 2 (40%) 

Urinary System 

Kidney (50) (50) (50) (50) 

Histiocytic sarcoma 1 (2%) 

Renal tubule, adenoma 1 (2%) 

Urinary bladder (50) (50) (50) (50) 

Systemic Lesions 

Multiple organsb (50) (50) (50) (50) 

Histiocytic sarcoma 2 (4%) 2 (4%) 

Lymphoma malignant 7 (14%) 8 (16%) 5 (10%) 6 (12%) 

Neoplasm Summary 

Total animals with primary neoplasmsc 40 41 42 47 

Total primary neoplasms 72 72 69 75 

Total animals with benign neoplasms 26 20 26 30 

Total benign neoplasms 36 25 33 36 

Total animals with malignant neoplasms 30 32 29 33 

Total malignant neoplasms 36 47 36 39 

Total animals with metastatic neoplasms 4 8 2 5 

Total metastatic neoplasms 4 23 2 13 

Total animals with malignant neoplasms

 of uncertain primary site 1 

a Number of animals examined microscopically at the site and the number of animals with neoplasm b Number of animals with any tissue examined microscopically 

Primary neoplasms: all neoplasms except metastatic neoplasms 
 

160 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE E2 

Statistical Analysis of Primary Neoplasms in Male Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Adrenal Cortex: Adenoma 

Overall ratea 

Adjusted rateb 0/50 (0%) 

0.0% 

0/50 (0%) 

0.0% 

1/50 (2%) 

2.6% 

3/50 (6%) 

8.3% 

Terminal ratec 0/36 (0%) 0/27 (0%) 1/38 (3%) 2/35 (6%) 

First incidence (days) 

Life table testd —e 

P=0.027 

— 

—f 731 (T) 

P=0.511 

727 

P=0.120 

Logistic regression testd 

Cochran-Armitage testd 

Fisher exact testd 

P=0.024 

P=0.021 

— 

— 

P=0.511 

P=0.500 

P=0.113 

P=0.121 

Harderian Gland: Adenoma 

Overall rate 3/50 (6%) 3/50 (6%) 1/50 (2%) 2/50 (4%) 

Adjusted rate 7.2% 10.4% 2.1% 5.7% 

Terminal rate 1/36 (3%) 2/27 (7%) 0/38 (0%) 2/35 (6%) 

First incidence (days) 618 708 563 731 (T) 

Life table test P=0.255N P=0.542 P=0.300N P=0.506N 

Logistic regression test P=0.266N P=0.622 P=0.280N P=0.503N 

Cochran-Armitage test P=0.271N 

Fisher exact test P=0.661N P=0.309N P=0.500N 

Harderian Gland: Adenoma or Carcinoma 

Overall rate 3/50 (6%) 3/50 (6%) 1/50 (2%) 4/50 (8%) 

Adjusted rate 7.2% 10.4% 2.1% 10.6% 

Terminal rate 1/36 (3%) 2/27 (7%) 0/38 (0%) 3/35 (9%) 

First incidence (days) 618 708 563 632 

Life table test P=0.532 P=0.542 P=0.300N P=0.497 

Logistic regression test P=0.506 P=0.622 P=0.280N P=0.493 

Cochran-Armitage test P=0.500 

Fisher exact test P=0.661N P=0.309N P=0.500 

Liver: Hemangiosarcoma 

Overall rate 3/50 (6%) 5/50 (10%) 4/50 (8%) 4/50 (8%) 

Adjusted rate 7.5% 16.4% 10.1% 10.1% 

Terminal rate 1/36 (3%) 3/27 (11%) 3/38 (8%) 2/35 (6%) 

First incidence (days) 675 663 685 638 

Life table test P=0.491 P=0.231 P=0.520 P=0.487 

Logistic regression test P=0.547N P=0.282 P=0.498 P=0.502 

Cochran-Armitage test P=0.454 

Fisher exact test P=0.357 P=0.500 P=0.500 

Liver: Hepatocellular Adenoma 

Overall rate 16/50 (32%) 16/50 (32%) 19/50 (38%) 18/50 (36%) 

Adjusted rate 40.5% 46.5% 47.3% 48.3% 

Terminal rate 13/36 (36%) 9/27 (33%) 17/38 (45%) 16/35 (46%) 

First incidence (days) 477 518 563 638 

Life table test P=0.394 P=0.261 P=0.406 P=0.380 

Logistic regression test P=0.368 P=0.414 P=0.331 P=0.429 

Cochran-Armitage test P=0.297 

Fisher exact test P=0.585N P=0.338 P=0.417 
AZT and AZT/"-Interferon A/D, NTP TR 469 161 

TABLE E2 

Statistical Analysis of Primary Neoplasms in Male Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Liver: Hepatocellular Carcinoma 

Overall rate 13/50 (26%) 20/50 (40%) 17/50 (34%) 14/50 (28%) 

Adjusted rate 31.9% 52.9% 40.1% 32.2% 

Terminal rate 9/36 (25%) 11/27 (41%) 13/38 (34%) 7/35 (20%) 

First incidence (days) 477 376 598 527 

Life table test P=0.435N P=0.029 P=0.316 P=0.483 

Logistic regression test P=0.511N P=0.087 P=0.245 P=0.481 

Cochran-Armitage test P=0.527 

Fisher exact test P=0.101 P=0.257 P=0.500 

Liver: Hepatocellular Adenoma or Carcinoma 

Overall rate 24/50 (48%) 31/50 (62%) 33/50 (66%) 29/50 (58%) 

Adjusted rate 56.8% 75.0% 74.9% 65.4% 

Terminal rate 18/36 (50%) 17/27 (63%) 27/38 (71%) 20/35 (57%) 

First incidence (days) 477 376 563 527 

Life table test P=0.307 P=0.016 P=0.112 P=0.213 

Logistic regression test P=0.194 P=0.050 P=0.043 P=0.226 

Cochran-Armitage test P=0.152 

Fisher exact test P=0.114 P=0.053 P=0.212 

Liver: Hepatocellular Carcinoma or Hepatoblastoma 

Overall rate 13/50 (26%) 21/50 (42%) 17/50 (34%) 14/50 (28%) 

Adjusted rate 31.9% 54.5% 40.1% 32.2% 

Terminal rate 9/36 (25%) 11/27 (41%) 13/38 (34%) 7/35 (20%) 

First incidence (days) 477 376 598 527 

Life table test P=0.411N P=0.019 P=0.316 P=0.483 

Logistic regression test P=0.481N P=0.057 P=0.245 P=0.481 

Cochran-Armitage test P=0.500N 

Fisher exact test P=0.069 P=0.257 P=0.500 

Liver: Hepatocellular Adenoma, Hepatocellular Carcinoma, or Hepatoblastoma 

Overall rate 24/50 (48%) 32/50 (64%) 33/50 (66%) 29/50 (58%) 

Adjusted rate 56.8% 75.8% 74.9% 65.4% 

Terminal rate 18/36 (50%) 17/27 (63%) 27/38 (71%) 20/35 (57%) 

First incidence (days) 477 376 563 527 

Life table test P=0.328 P=0.011 P=0.112 P=0.213 

Logistic regression test P=0.213 P=0.030 P=0.043 P=0.226 

Cochran-Armitage test P=0.167 

Fisher exact test P=0.079 P=0.053 P=0.212 

Lung: Alveolar/bronchiolar Adenoma 

Overall rate 10/49 (20%) 4/50 (8%) 9/50 (18%) 8/50 (16%) 

Adjusted rate 26.4% 14.8% 23.7% 22.0% 

Terminal rate 8/35 (23%) 4/27 (15%) 9/38 (24%) 7/35 (20%) 

First incidence (days) 660 731 (T) 731 (T) 682 

Life table test P=0.416N P=0.174N P=0.430N P=0.399N 

Logistic regression test P=0.432N P=0.128N P=0.463N P=0.374N 

Cochran-Armitage test P=0.484N 

Fisher exact test P=0.068N P=0.480N P=0.379N 
162 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE E2 

Statistical Analysis of Primary Neoplasms in Male Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Lung: Alveolar/bronchiolar Carcinoma 

Overall rate 6/49 (12%) 2/50 (4%) 7/50 (14%) 6/50 (12%) 

Adjusted rate 15.6% 7.4% 17.8% 15.8% 

Terminal rate 4/35 (11%) 2/27 (7%) 6/38 (16%) 4/35 (11%) 

First incidence (days) 542 731 (T) 699 672 

Life table test P=0.399 P=0.224N P=0.552 P=0.612 

Logistic regression test P=0.389 P=0.165N P=0.513 P=0.599N 

Cochran-Armitage test P=0.352 

Fisher exact test P=0.128N P=0.516 P=0.606N 

Lung: Alveolar/bronchiolar Adenoma or Carcinoma 

Overall rate 16/49 (33%) 6/50 (12%) 14/50 (28%) 14/50 (28%) 

Adjusted rate 40.3% 22.2% 35.8% 36.4% 

Terminal rate 12/35 (34%) 6/27 (22%) 13/38 (34%) 11/35 (31%) 

First incidence (days) 542 731 (T) 699 672 

Life table test P=0.479N P=0.063N P=0.330N P=0.421N 

Logistic regression test P=0.494N P=0.031N P=0.379N P=0.369N 

Cochran-Armitage test P=0.493 

Fisher exact test P=0.012N P=0.388N P=0.388N 

Thyroid Gland (Follicular Cell): Adenoma 

Overall rate 4/50 (8%) 2/50 (4%) 0/50 (0%) 1/49 (2%) 

Adjusted rate 11.1% 7.4% 0.0% 2.9% 

Terminal rate 4/36 (11%) 2/27 (7%) 0/38 (0%) 1/35 (3%) 

First incidence (days) 731 (T) 731 (T) — 731 (T) 

Life table test P=0.038N P=0.475N P=0.056N P=0.187N 

Logistic regression test P=0.038N P=0.475N P=0.056N P=0.187N 

Cochran-Armitage test P=0.044N 

Fisher exact test P=0.339N P=0.059N P=0.187N 

All Organs: Hemangiosarcoma 

Overall rate 3/50 (6%) 6/50 (12%) 5/50 (10%) 4/50 (8%) 

Adjusted rate 7.5% 18.7% 12.7% 10.1% 

Terminal rate 1/36 (3%) 3/27 (11%) 4/38 (11%) 2/35 (6%) 

First incidence (days) 675 624 685 638 

Life table test P=0.497 P=0.145 P=0.381 P=0.487 

Logistic regression test P=0.532N P=0.191 P=0.355 P=0.502 

Cochran-Armitage test P=0.456 

Fisher exact test P=0.243 P=0.357 P=0.500 

All Organs: Malignant Lymphoma 

Overall rate 7/50 (14%) 8/50 (16%) 5/50 (10%) 6/50 (12%) 

Adjusted rate 18.8% 25.2% 12.5% 15.6% 

Terminal rate 6/36 (17%) 5/27 (19%) 4/38 (11%) 4/35 (11%) 

First incidence (days) 716 579 624 522 

Life table test P=0.278N P=0.290 P=0.345N P=0.517N 

Logistic regression test P=0.292N P=0.383 P=0.374N P=0.492N 

Cochran-Armitage test P=0.319N 

Fisher exact test P=0.500 P=0.380N P=0.500N 
163 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE E2 

Statistical Analysis of Primary Neoplasms in Male Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

All Organs: Benign Neoplasms 

Overall rate 26/50 (52%) 20/50 (40%) 26/50 (52%) 30/50 (60%) 

Adjusted rate 63.0% 58.4% 64.8% 76.8% 

Terminal rate 21/36 (58%) 13/27 (48%) 24/38 (63%) 26/35 (74%) 

First incidence (days) 477 518 563 638 

Life table test P=0.243 P=0.569 P=0.478N P=0.230 

Logistic regression test P=0.207 P=0.341N P=0.582N P=0.283 

Cochran-Armitage test P=0.141 

Fisher exact test P=0.158N P=0.579N P=0.273 

All Organs: Malignant Neoplasms 

Overall rate 30/50 (60%) 33/50 (66%) 29/50 (58%) 33/50 (66%) 

Adjusted rate 63.7% 74.2% 64.3% 67.3% 

Terminal rate 19/36 (53%) 16/27 (59%) 22/38 (58%) 19/35 (54%) 

First incidence (days) 374 296 598 522 

Life table test P=0.484N P=0.081 P=0.418N P=0.347 

Logistic regression test P=0.401 P=0.313 P=0.529N P=0.446 

Cochran-Armitage test P=0.397 

Fisher exact test P=0.339 P=0.500N P=0.339 

All Organs: Benign or Malignant Neoplasms 

Overall rate 40/50 (80%) 41/50 (82%) 42/50 (84%) 47/50 (94%) 

Adjusted rate 83.3% 89.1% 89.4% 95.9% 

Terminal rate 28/36 (78%) 22/27 (81%) 33/38 (87%) 33/35 (94%) 

First incidence (days) 374 296 563 522 

Life table test P=0.272 P=0.064 P=0.559 P=0.121 

Logistic regression test P=0.044 P=0.293 P=0.311 P=0.043 

Cochran-Armitage test P=0.031 

Fisher exact test P=0.500 P=0.398 P=0.036 

(T)Terminal sacrifice 

a Number of neoplasm-bearing animals/number of animals examined. Denominator is number of animals examined microscopically for adrenal gland, liver, 

lung, and thyroid gland; for other tissues, denominator is number of animals necropsied. b Kaplan-Meier estimated neoplasm incidence at the end of the study after adjustment for intercurrent mortality 

Observed incidence at terminal kill 

d	 Beneath the vehicle control incidence are the P values associated with the trend test. Beneath the dosed group incidence are the P values corresponding to 

pairwise comparisons between the vehicle controls and that dosed group. The life table test regards neoplasms in animals dying prior to terminal kill as being 

(directly or indirectly) the cause of death. The logistic regression test regards these lesions as nonfatal. The Cochran-Armitage and Fisher exact tests compare 

directly the overall incidence rates. For all tests, a negative trend or a lower incidence in a dose group is indicated by N. e Not applicable; no neoplasms in animal group f Value of statistic cannot be computed. 
 

 

 

 

 

 

 

 

 

 

164 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE E3 

Summary of the Incidence of Nonneoplastic Lesions in Male Mice in the 2-Year Gavage Study 

of AZT/500 U "-Interferon A/Da 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Disposition Summary 

Animals initially in study 50 50 50 50 

Early deaths 

Accidental deaths 2 3 

Moribund 13 14 5 9 

Natural deaths 1 7 4 6 

Survivors 

Terminal sacrifice 36 27 38 35 

Animals examined microscopically 50 50 50 50 

Alimentary System 

Esophagus (50) (50) (50) (50) 

Inflammation, chronic 1 (2%) 

Perforation 2 (4%) 1 (2%) 

Gallbladder (50) (47) (50) (46) 

Inflammation, chronic 1 (2%) 

Intestine large, colon (50) (50) (50) (50) 

Edema 2 (4%) 

Parasite metazoan 1 (2%) 

Intestine large, cecum (50) (50) (50) (49) 

Edema 1 (2%) 2 (4%) 1 (2%) 

Parasite metazoan 3 (6%) 7 (14%) 3 (6%) 5 (10%) 

Intestine small, ileum (50) (48) (49) (50) 

Peyer’s patch, hyperplasia, lymphoid 1 (2%) 1 (2%) 

Liver (50) (50) (50) (50) 

Angiectasis 2 (4%) 2 (4%) 1 (2%) 

Basophilic focus 4 (8%) 1 (2%) 2 (4%) 1 (2%) 

Clear cell focus 1 (2%) 1 (2%) 1 (2%) 1 (2%) 

Eosinophilic focus 2 (4%) 1 (2%) 6 (12%) 1 (2%) 

Hematopoietic cell proliferation 1 (2%) 1 (2%) 

Inflammation, chronic 39 (78%) 38 (76%) 38 (76%) 44 (88%) 

Metaplasia, osseous 2 (4%) 1 (2%) 1 (2%) 

Mixed cell focus 1 (2%) 2 (4%) 1 (2%) 

Necrosis, focal 1 (2%) 7 (14%) 4 (8%) 

Pigmentation, focal 2 (4%) 1 (2%) 1 (2%) 

Vacuolization cytoplasmic 3 (6%) 2 (4%) 1 (2%) 

Bile duct, hyperplasia 26 (52%) 26 (52%) 26 (52%) 23 (46%) 

Hepatocyte, karyomegaly 33 (66%) 31 (62%) 35 (70%) 40 (80%) 

Mesentery (1) (2) (1) 

Fat, necrosis 1 (100%) 1 (100%) 

Pancreas (50) (50) (50) (50) 

Cyst 1 (2%) 2 (4%) 

Acinus, atrophy, diffuse 2 (4%) 1 (2%) 2 (4%) 

Salivary glands (50) (50) (50) (50) 

Inflammation, chronic 1 (2%) 3 (6%) 1 (2%) 1 (2%) 

a Number of animals examined microscopically at the site and the number of animals with lesion 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 165 

TABLE E3 

Summary of the Incidence of Nonneoplastic Lesions in Male Mice in the 2-Year Gavage Study 

of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Alimentary System (continued) 

Stomach, forestomach (50) (50) (50) (50) 

Ulcer 1 (2%) 1 (2%) 

Epithelium, hyperplasia 2 (4%) 2 (4%) 3 (6%) 

Stomach, glandular (50) (50) (50) (50) 

Edema 2 (4%) 

Erosion 1 (2%) 

Ulcer 1 (2%) 

Cardiovascular System 

Blood vessel (50) (50) (50) (50) 

Hypertrophy 1 (2%) 1 (2%) 

Inflammation, chronic 1 (2%) 2 (4%) 2 (4%) 

Heart (50) (50) (50) (50) 

Fibrosis 1 (2%) 

Hemorrhage 1 (2%) 

Inflammation, chronic 5 (10%) 1 (2%) 

Mineralization 2 (4%) 1 (2%) 

Thrombosis 1 (2%) 1 (2%) 

Endocrine System 

Adrenal cortex (50) (50) (50) (50) 

Accessory adrenal cortical nodule 7 (14%) 6 (12%) 1 (2%) 1 (2%) 

Cytoplasmic alteration, focal 9 (18%) 7 (14%) 10 (20%) 12 (24%) 

Hyperplasia, focal 7 (14%) 3 (6%) 8 (16%) 16 (32%) 

Hypertrophy, diffuse 1 (2%) 

Hypertrophy, focal 11 (22%) 5 (10%) 14 (28%) 13 (26%) 

Capsule, hyperplasia, focal 4 (8%) 2 (4%) 3 (6%) 4 (8%) 

Adrenal medulla (50) (50) (50) (50) 

Hyperplasia 2 (4%) 1 (2%) 1 (2%) 

Islets, pancreatic (50) (50) (50) (50) 

Hyperplasia 4 (8%) 4 (8%) 5 (10%) 7 (14%) 

Parathyroid gland (48) (47) (48) (47) 

Cyst 1 (2%) 1 (2%) 1 (2%) 

Pituitary gland (48) (43) (48) (47) 

Pars distalis, cyst 1 (2%) 1 (2%) 

Pars distalis, hemorrhage 1 (2%) 

Pars distalis, hyperplasia, focal 1 (2%) 

Thyroid gland (50) (50) (50) (49) 

Degeneration, cystic, focal 12 (24%) 14 (28%) 11 (22%) 14 (29%) 

Follicle, cyst 3 (6%) 4 (8%) 7 (14%) 5 (10%) 

Follicular cell, hyperplasia 12 (24%) 15 (30%) 19 (38%) 10 (20%) 

General Body System 

None 
 

 

 

 

 

 

 

 

 

 

 

166 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE E3 

Summary of the Incidence of Nonneoplastic Lesions in Male Mice in the 2-Year Gavage Study 

of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Genital System 

Epididymis (50) (50) (50) (50) 

Granuloma sperm 2 (4%) 

Preputial gland (48) (48) (50) (50) 

Cyst 10 (21%) 7 (15%) 4 (8%) 4 (8%) 

Inflammation, chronic 7 (15%) 13 (27%) 6 (12%) 4 (8%) 

Testes (50) (50) (50) (50) 

Atrophy 1 (2%) 1 (2%) 3 (6%) 2 (4%) 

Cyst 1 (2%) 

Hematopoietic System 

Bone marrow (50) (50) (50) (50) 

Hyperplasia 14 (28%) 23 (46%) 16 (32%) 21 (42%) 

Lymph node (5) (8) (5) (5) 

Bronchial, hyperplasia, lymphoid 1 (20%) 1 (20%) 

Mediastinal, hemorrhage 1 (13%) 

Mediastinal, hyperplasia, lymphoid 1 (20%) 1 (20%) 

Pancreatic, hyperplasia, lymphoid 1 (20%) 

Renal, hemorrhage 1 (13%) 

Lymph node, mandibular (46) (47) (49) (46) 

Hyperplasia, lymphoid 2 (4%) 4 (9%) 2 (4%) 2 (4%) 

Pigmentation 4 (9%) 10 (21%) 13 (27%) 8 (17%) 

Lymph node, mesenteric (50) (48) (50) (47) 

Hematopoietic cell proliferation 7 (14%) 6 (13%) 1 (2%) 7 (15%) 

Hemorrhage 19 (38%) 15 (31%) 17 (34%) 18 (38%) 

Hyperplasia, lymphoid 6 (12%) 5 (10%) 12 (24%) 8 (17%) 

Spleen (50) (49) (49) (50) 

Atrophy 1 (2%) 1 (2%) 1 (2%) 

Hematopoietic cell proliferation 20 (40%) 29 (59%) 17 (35%) 23 (46%) 

Hyperplasia, lymphoid 6 (12%) 4 (8%) 4 (8%) 1 (2%) 

Necrosis, focal 1 (2%) 

Pigmentation 1 (2%) 1 (2%) 

Thymus (45) (40) (42) (43) 

Atrophy 1 (2%) 3 (8%) 

Integumentary System 

Skin (50) (50) (50) (50) 

Mineralization 1 (2%) 

Ulcer 2 (4%) 2 (4%) 

Subcutaneous tissue, edema 4 (8%) 4 (8%) 2 (4%) 1 (2%) 

Musculoskeletal System 

Bone (50) (50) (50) (50) 

Hyperostosis 42 (84%) 31 (62%) 39 (78%) 39 (78%) 

Femur, osteopetrosis 1 (2%) 

Skeletal muscle (50) (50) (50) (50) 

Atrophy 2 (4%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 167 

TABLE E3 

Summary of the Incidence of Nonneoplastic Lesions in Male Mice in the 2-Year Gavage Study 

of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Nervous System 

Brain (50) (50) (50) (50) 

Atrophy, focal 1 (2%) 

Necrosis 1 (2%) 

Respiratory System 

Lung (49) (50) (50) (50) 

Hemorrhage 1 (2%) 1 (2%) 5 (10%) 1 (2%) 

Infiltration cellular, histiocyte 6 (12%) 6 (12%) 8 (16%) 4 (8%) 

Inflammation, chronic 1 (2%) 1 (2%) 1 (2%) 1 (2%) 

Inflammation, suppurative 1 (2%) 

Thrombosis 1 (2%) 1 (2%) 

Alveolar epithelium, hyperplasia 1 (2%) 2 (4%) 

Nose (50) (50) (50) (50) 

Inflammation, suppurative 1 (2%) 1 (2%) 2 (4%) 5 (10%) 

Special Senses System 

Eye (1) (1) (1) 

Atrophy 1 (100%) 1 (100%) 

Inflammation, chronic 1 (100%) 

Urinary System 

Kidney (50) (50) (50) (50) 

Infarct 1 (2%) 1 (2%) 

Inflammation, chronic 1 (2%) 

Metaplasia, focal, osseous 2 (4%) 1 (2%) 

Nephropathy 47 (94%) 46 (92%) 44 (88%) 49 (98%) 

Pelvis, dilatation 1 (2%) 1 (2%) 

Renal tubule, accumulation, hyaline droplet 1 (2%) 

Renal tubule, hyaline droplet 1 (2%) 

Renal tubule, necrosis 1 (2%) 

Renal tubule, pigmentation 1 (2%) 1 (2%) 1 (2%) 1 (2%) 

Transitional epithelium, hyperplasia 1 (2%) 
168 AZT and AZT/"-Interferon A/D, NTP TR 469 
169 

APPENDIX F 

SUMMARY OF LESIONS IN FEMALE MICE 

IN THE 2-YEAR GAVAGE STUDY 

OF AZT/500 U "-INTERFERON A/D 

TABLE F1 Summary of the Incidence of Neoplasms in Female Mice 

in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D ................... 170 

TABLE F2 Statistical Analysis of Primary Neoplasms in Female Mice 

in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D ................... 174 

TABLE F3 Summary of the Incidence of Nonneoplastic Lesions in Female Mice 

in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D ................... 178 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

170 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE F1 

Summary of the Incidence of Neoplasms in Female Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/Da 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Disposition Summary 

Animals initially in study 50 50 50 50 

Early deaths 

Accidental deaths 3 4 2 4 

Moribund 7 8 11 12 

Natural deaths 7 6 5 9 

Survivors 

Terminal sacrifice 33 32 32 24 

Missing 1 

Animals examined microscopically 50 50 50 49 

Alimentary System 

Gallbladder (48) (47) (49) (48) 

Fibrosarcoma, metastatic, uterus 1 (2%) 

Intestine large, colon (50) (48) (50) (49) 

Leiomyoma 1 (2%) 

Intestine small, jejunum (50) (49) (49) (49) 

Histiocytic sarcoma 1 (2%) 

Intestine small, ileum (49) (49) (46) (47) 

Liver (50) (50) (50) (49) 

Carcinoma, metastatic, uterus 1 (2%) 

Fibrosarcoma, metastatic, mesentery 1 (2%) 

Fibrous histiocytoma, metastatic,

 lymph node, mesenteric 1 (2%) 

Hemangiosarcoma 1 (2%) 

Hemangiosarcoma, multiple 1 (2%) 

Hepatocellular carcinoma 12 (24%) 2 (4%) 3 (6%) 6 (12%) 

Hepatocellular carcinoma, multiple 1 (2%) 2 (4%) 2 (4%) 4 (8%) 

Hepatocellular adenoma 8 (16%) 14 (28%) 11 (22%) 11 (22%) 

Hepatocellular adenoma, multiple 3 (6%) 3 (6%) 3 (6%) 3 (6%) 

Histiocytic sarcoma 2 (4%) 3 (6%) 1 (2%) 

Mesentery (10) (11) (9) (6) 

Carcinoma, metastatic, uterus 1 (11%) 

Fibrosarcoma 1 (11%) 

Hemangioma 1 (10%) 

Squamous cell carcinoma, metastatic, vagina 1 (17%) 

Pancreas (50) (50) (50) (49) 

Carcinoma, metastatic, uterus 1 (2%) 

Fibrosarcoma, metastatic, mesentery 1 (2%) 

Histiocytic sarcoma 1 (2%) 

Salivary glands (50) (49) (49) (48) 

Stomach, forestomach (50) (50) (50) (49) 

Carcinoma, metastatic, uterus 1 (2%) 

Squamous cell carcinoma 1 (2%) 

Squamous cell papilloma 1 (2%) 1 (2%) 1 (2%) 1 (2%) 

Stomach, glandular (50) (50) (50) (49) 

Carcinoma, metastatic, uterus 1 (2%) 

Fibrosarcoma, metastatic, mesentery 1 (2%) 

Histiocytic sarcoma 1 (2%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 171 

TABLE F1 

Summary of the Incidence of Neoplasms in Female Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Cardiovascular System 

Blood vessel (50) (50) (50) (49) 

Heart (50) (50) (50) (49) 

Endocrine System 

Adrenal cortex (49) (50) (50) (49) 

Histiocytic sarcoma 1 (2%) 

Capsule, adenoma 1 (2%) 

Adrenal medulla (49) (49) (49) (48) 

Pheochromocytoma malignant 2 (4%) 

Pheochromocytoma benign 1 (2%) 

Islets, pancreatic (50) (50) (50) (49) 

Adenoma 1 (2%) 

Pituitary gland (50) (47) (48) (47) 

Pars distalis, adenoma 7 (14%) 3 (6%) 4 (8%) 5 (11%) 

Pars distalis, carcinoma 1 (2%) 

Pars intermedia, adenoma 2 (4%) 1 (2%) 

Thyroid gland (50) (50) (50) (49) 

Bilateral, follicular cell, carcinoma 1 (2%) 

Follicular cell, adenoma 1 (2%) 1 (2%) 

General Body System 

None 

Genital System 

Ovary (49) (49) (49) (49) 

Cystadenoma 4 (8%) 2 (4%) 

Fibrosarcoma, metastatic, uterus 1 (2%) 

Histiocytic sarcoma 1 (2%) 2 (4%) 1 (2%) 

Luteoma 1 (2%) 

Uterus (50) (50) (50) (49) 

Fibrosarcoma 1 (2%) 

Hemangiosarcoma 1 (2%) 

Histiocytic sarcoma 2 (4%) 3 (6%) 1 (2%) 

Leiomyosarcoma 1 (2%) 

Endometrium, carcinoma 1 (2%) 1 (2%) 

Endometrium, polyp stromal 4 (8%) 3 (6%) 2 (4%) 

Endometrium, sarcoma stromal 1 (2%) 

Vagina (49) (44) (48) (48) 

Leiomyosarcoma, metastatic, uterus 1 (2%) 

Squamous cell carcinoma 5 (10%) 6 (13%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

172 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE F1 

Summary of the Incidence of Neoplasms in Female Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Hematopoietic System 

Bone marrow (50) (50) (50) (49) 

Histiocytic sarcoma 1 (2%) 

Lymph node (4) (8) (10) (10) 

Histiocytic sarcoma 1 (13%) 

Iliac, histiocytic sarcoma 1 (13%) 1 (10%) 

Inguinal, histiocytic sarcoma 1 (13%) 

Inguinal, squamous cell carcinoma,

 metastatic, vagina 1 (10%) 

Mediastinal, fibrosarcoma, metastatic,

 mesentery 1 (10%) 

Mediastinal, fibrous histiocytoma,

 metastatic, lymph node, mesenteric 1 (10%) 

Mediastinal, histiocytic sarcoma 1 (13%) 

Renal, histiocytic sarcoma 1 (13%) 1 (10%) 

Lymph node, mandibular (49) (45) (46) (48) 

Histiocytic sarcoma 1 (2%) 

Lymph node, mesenteric (50) (47) (49) (49) 

Fibrous histiocytoma 1 (2%) 1 (2%) 

Histiocytic sarcoma 2 (4%) 1 (2%) 

Spleen (50) (50) (50) (49) 

Hemangiosarcoma 1 (2%) 

Histiocytic sarcoma 1 (2%) 2 (4%) 

Thymus (47) (46) (46) (45) 

Fibrosarcoma, metastatic, mesentery 1 (2%) 

Histiocytic sarcoma 2 (4%) 

Integumentary System 

Mammary gland (50) (49) (50) (49) 

Carcinoma 1 (2%) 

Skin (49) (50) (50) (49) 

Squamous cell carcinoma, metastatic, vagina 1 (2%) 

Subcutaneous tissue, fibrosarcoma 1 (2%) 4 (8%) 2 (4%) 1 (2%) 

Musculoskeletal System 

Bone (49) (50) (50) (49) 

Osteosarcoma 1 (2%) 1 (2%) 

Skeletal muscle (50) (50) (50) (49) 

Carcinoma, metastatic, uterus 1 (2%) 

Fibrosarcoma, metastatic, mesentery 1 (2%) 

Fibrosarcoma, metastatic, uterus 1 (2%) 

Sarcoma 1 (2%) 

Nervous System 

Brain (50) (50) (50) (49) 

Carcinoma, metastatic, pituitary gland 1 (2%) 

Spinal cord (2) (2) (7) (3) 
 

 

 

 

 

 

 

173 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE F1 

Summary of the Incidence of Neoplasms in Female Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

Vehicle Control 

30 mg AZT/kg + 

500 U "-IFN A/D 

60 mg AZT/kg + 

500 U "-IFN A/D 

120 mg AZT/kg + 

500 U "-IFN A/D 

Respiratory System 

Lung 

Alveolar/bronchiolar adenoma

Alveolar/bronchiolar carcinoma

Carcinoma, metastatic, uterus

Hepatocellular carcinoma, metastatic, liver

Histiocytic sarcoma

(50) 

1 (2%) 

1 (2%) 

1 (2%) 

(50) 

3 (6%) 

2 (4%) 

1 (2%) 

(50) 

1 (2%) 

1 (2%) 

1 (2%) 

1 (2%) 

(49) 

1 (2%) 

1 (2%) 

Special Senses System 

Harderian gland

Adenoma

 (2)

 2 (100%)

 (1) 

1 (100%) 

Urinary System 

Kidney 

Histiocytic sarcoma

Osteosarcoma, metastatic, bone

Squamous cell carcinoma, metastatic, vagina

Urinary bladder 

(50) 

(50) 

(50) 

2 (4%) 

1 (2%) 

(50) 

(50) 

(50) 

(49) 

1 (2%) 

(49) 

Systemic Lesions 

Multiple organsb 

Histiocytic sarcoma

Lymphoma malignant

(50) 

3 (6%) 

13 (26%) 

(50) 

3 (6%) 

8 (16%) 

(50) 

1 (2%) 

12 (24%) 

(49) 

11 (22%) 

Neoplasm Summary 

Total animals with primary neoplasmsc 

Total primary neoplasms 

Total animals with benign neoplasms 

Total benign neoplasms 

Total animals with malignant neoplasms 

Total malignant neoplasms 

Total animals with metastatic neoplasms 

Total metastatic neoplasms 

35 

60 

23 

28 

23 

32 

2 

2 

39 

58 

25 

33 

23 

25 

1 

1 

38 

61 

23 

26 

28 

35 

5 

19 

36 

62 

20 

27 

28 

35 

1 

4 

a Number of animals examined microscopically at the site and the number of animals with neoplasm b Number of animals with any tissue examined microscopically 

Primary neoplasms: all neoplasms except metastatic neoplasms 
174 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE F2 

Statistical Analysis of Primary Neoplasms in Female Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Liver: Hepatocellular Adenoma 

Overall ratea 

Adjusted rateb 11/50 (22%) 

31.1% 

17/50 (34%) 

51.5% 

14/50 (28%) 

42.4% 

14/49 (29%) 

49.0% 

Terminal ratec 9/33 (27%) 16/32 (50%) 13/32 (41%) 10/24 (42%) 

First incidence (days) 

Life table testd 

649 

P=0.103 

667 

P=0.097 

713 

P=0.282 

617 

P=0.096 

Logistic regression testd 

Cochran-Armitage testd 

Fisher exact testd 

P=0.173 

P=0.340 

P=0.052 

P=0.133 

P=0.239 

P=0.322 

P=0.161 

P=0.301 

Liver: Hepatocellular Carcinoma 

Overall rate 13/50 (26%) 4/50 (8%) 5/50 (10%) 10/49 (20%) 

Adjusted rate 35.4% 11.8% 14.7% 32.5% 

Terminal rate 10/33 (30%) 3/32 (9%) 3/32 (9%) 5/24 (21%) 

First incidence (days) 649 628 707 589 

Life table test P=0.473N P=0.025N P=0.047N P=0.573 

Logistic regression test P=0.357N P=0.026N P=0.041N P=0.448N 

Cochran-Armitage test P=0.287N 

Fisher exact test P=0.016N P=0.033N P=0.337N 

Liver: Hepatocellular Adenoma or Carcinoma 

Overall rate 20/50 (40%) 20/50 (40%) 18/50 (36%) 22/49 (45%) 

Adjusted rate 53.6% 58.7% 52.9% 65.9% 

Terminal rate 16/33 (48%) 18/32 (56%) 16/32 (50%) 13/24 (54%) 

First incidence (days) 649 628 707 589 

Life table test P=0.099 P=0.499 P=0.478N P=0.092 

Logistic regression test P=0.198 P=0.360 P=0.533N P=0.191 

Cochran-Armitage test P=0.393 

Fisher exact test P=0.581N P=0.418N P=0.386 

Lung: Alveolar/bronchiolar Adenoma 

Overall rate 1/50 (2%) 3/50 (6%) 1/50 (2%) 1/49 (2%) 

Adjusted rate 3.0% 9.4% 3.1% 4.2% 

Terminal rate 1/33 (3%) 3/32 (9%) 1/32 (3%) 1/24 (4%) 

First incidence (days) 729 (T) 729 (T) 729 (T) 729 (T) 

Life table test P=0.526N P=0.293 P=0.755 P=0.689 

Logistic regression test P=0.526N P=0.293 P=0.755 P=0.689 

Cochran-Armitage test P=0.433N 

Fisher exact test P=0.309 P=0.753N P=0.747 

Lung: Alveolar/bronchiolar Adenoma or Carcinoma 

Overall rate 1/50 (2%) 4/50 (8%) 2/50 (4%) 2/49 (4%) 

Adjusted rate 3.0% 12.5% 5.6% 7.2% 

Terminal rate 1/33 (3%) 4/32 (13%) 1/32 (3%) 1/24 (4%) 

First incidence (days) 729 (T) 729 (T) 647 673 

Life table test P=0.385 P=0.169 P=0.484 P=0.398 

Logistic regression test P=0.445 P=0.169 P=0.495 P=0.451 

Cochran-Armitage test P=0.492 

Fisher exact test P=0.181 P=0.500 P=0.492 
AZT and AZT/"-Interferon A/D, NTP TR 469 175 

TABLE F2 

Statistical Analysis of Primary Neoplasms in Female Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Ovary: Cystadenoma 

Overall rate 0/49 (0%) 4/49 (8%) 0/49 (0%) 2/49 (4%) 

Adjusted rate 0.0% 12.5% 0.0% 6.7% 

Terminal rate 0/33 (0%) 4/32 (13%) 0/31 (0%) 1/24 (4%) e First incidence (days) — 729 (T) — 604 

f Life table test P=0.336 P=0.058 — P=0.193 

Logistic regression test P=0.395 P=0.058 — P=0.231 

Cochran-Armitage test P=0.426 

Fisher exact test P=0.059 — P=0.247 

Pituitary Gland (Pars Distalis): Adenoma 

Overall rate 7/50 (14%) 3/47 (6%) 4/48 (8%) 5/47 (11%) 

Adjusted rate 18.3% 9.4% 10.9% 17.9% 

Terminal rate 4/33 (12%) 3/32 (9%) 2/31 (6%) 3/24 (13%) 

First incidence (days) 593 729 (T) 436 589 

Life table test P=0.480N P=0.190N P=0.299N P=0.562N 

Logistic regression test P=0.385N P=0.196N P=0.285N P=0.456N 

Cochran-Armitage test P=0.365N 

Fisher exact test P=0.185N P=0.286N P=0.424N 

Pituitary Gland (Pars Distalis): Adenoma or Carcinoma 

Overall rate 8/50 (16%) 3/47 (6%) 4/48 (8%) 5/47 (11%) 

Adjusted rate 20.7% 9.4% 10.9% 17.9% 

Terminal rate 4/33 (12%) 3/32 (9%) 2/31 (6%) 3/24 (13%) 

First incidence (days) 593 729 (T) 436 589 

Life table test P=0.364N P=0.129N P=0.214N P=0.457N 

Logistic regression test P=0.276N P=0.130N P=0.198N P=0.350N 

Cochran-Armitage test P=0.258N 

Fisher exact test P=0.120N P=0.199N P=0.318N 

Skin (Subcutaneous Tissue): Fibrosarcoma 

Overall rate 1/50 (2%) 4/50 (8%) 2/50 (4%) 1/49 (2%) 

Adjusted rate 2.5% 10.9% 5.7% 2.6% 

Terminal rate 0/33 (0%) 2/32 (6%) 1/32 (3%) 0/24 (0%) 

First incidence (days) 688 467 656 603 

Life table test P=0.517N P=0.158 P=0.472 P=0.721 

Logistic regression test P=0.446N P=0.179 P=0.498 P=0.759 

Cochran-Armitage test P=0.443N 

Fisher exact test P=0.181 P=0.500 P=0.747 

Uterus: Stromal Polyp 

Overall rate 4/50 (8%) 0/50 (0%) 3/50 (6%) 2/49 (4%) 

Adjusted rate 10.7% 0.0% 8.7% 7.4% 

Terminal rate 2/33 (6%) 0/32 (0%) 2/32 (6%) 1/24 (4%) 

First incidence (days) 593 — 656 699 

Life table test P=0.477N P=0.076N P=0.518N P=0.461N 

Logistic regression test P=0.415N P=0.067N P=0.504N P=0.382N 

Cochran-Armitage test P=0.388N 

Fisher exact test P=0.059N P=0.500N P=0.349N 
 

176 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE F2 

Statistical Analysis of Primary Neoplasms in Female Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Uterus: Stromal Polyp or Stromal Sarcoma 

Overall rate 4/50 (8%) 0/50 (0%) 3/50 (6%) 3/49 (6%) 

Adjusted rate 10.7% 0.0% 8.7% 10.9% 

Terminal rate 2/33 (6%) 0/32 (0%) 2/32 (6%) 1/24 (4%) 

First incidence (days) 593 — 656 699 

Life table test P=0.454 P=0.076N P=0.518N P=0.633N 

Logistic regression test P=0.516 P=0.067N P=0.504N P=0.559N 

Cochran-Armitage test P=0.549 

Fisher exact test P=0.059N P=0.500N P=0.511N 

Vagina: Squamous Cell Carcinoma 

Overall rate 0/50 (0%) 0/50 (0%) 5/50 (10%) 6/49 (12%) 

Adjusted rate 0.0% 0.0% 15.6% 21.1% 

Terminal rate 0/33 (0%) 0/32 (0%) 5/32 (16%) 3/24 (13%) 

First incidence (days) — — 729 (T) 631 

Life table test P<0.001 — P=0.030 P=0.008 

Logistic regression test P<0.001 — P=0.030 P=0.011 

Cochran-Armitage test P=0.001 

Fisher exact test — P=0.028 P=0.012 

All Organs: Histiocytic Sarcoma 

Overall rate 3/50 (6%) 3/50 (6%) 1/50 (2%) 0/49 (0%) 

Adjusted rate 7.8% 8.0% 2.5% 0.0% 

Terminal rate 1/33 (3%) 1/32 (3%) 0/32 (0%) 0/24 (0%) 

First incidence (days) 675 561 634 — 

Life table test P=0.064N P=0.606 P=0.339N P=0.179N 

Logistic regression test P=0.045N P=0.658 P=0.216N P=0.137N 

Cochran-Armitage test P=0.044N 

Fisher exact test P=0.661N P=0.309N P=0.125N 

All Organs: Malignant Lymphoma 

Overall rate 13/50 (26%) 8/50 (16%) 12/50 (24%) 11/49 (22%) 

Adjusted rate 34.6% 19.6% 32.5% 34.9% 

Terminal rate 9/33 (27%) 2/32 (6%) 8/32 (25%) 5/24 (21%) 

First incidence (days) 675 441 514 604 

Life table test P=0.365 P=0.232N P=0.547N P=0.477 

Logistic regression test P=0.528 P=0.177N P=0.525N P=0.551N 

Cochran-Armitage test P=0.490N 

Fisher exact test P=0.163N P=0.500N P=0.430N 

All Organs: Benign Neoplasms 

Overall rate 23/50 (46%) 25/50 (50%) 23/50 (46%) 20/49 (41%) 

Adjusted rate 57.2% 75.7% 59.8% 61.1% 

Terminal rate 16/33 (48%) 24/32 (75%) 17/32 (53%) 12/24 (50%) 

First incidence (days) 593 667 436 589 

Life table test P=0.352 P=0.329 P=0.516 P=0.366 

Logistic regression test P=0.437N P=0.180 P=0.559 P=0.539N 

Cochran-Armitage test P=0.291N 

Fisher exact test P=0.421 P=0.579N P=0.376N 
177 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE F2 

Statistical Analysis of Primary Neoplasms in Female Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

All Organs: Malignant Neoplasms 

Overall rate 23/50 (46%) 23/50 (46%) 28/50 (56%) 28/49 (57%) 

Adjusted rate 57.2% 52.9% 64.9% 71.3% 

Terminal rate 16/33 (48%) 12/32 (38%) 17/32 (53%) 13/24 (54%) 

First incidence (days) 649 441 436 589 

Life table test P=0.025 P=0.461 P=0.190 P=0.036 

Logistic regression test P=0.081 P=0.521 P=0.190 P=0.135 

Cochran-Armitage test P=0.096 

Fisher exact test P=0.579N P=0.212 P=0.182 

All Organs: Benign or Malignant Neoplasms 

Overall rate 35/50 (70%) 39/50 (78%) 38/50 (76%) 36/49 (73%) 

Adjusted rate 81.3% 90.6% 84.4% 89.9% 

Terminal rate 25/33 (76%) 28/32 (88%) 25/32 (78%) 20/24 (83%) 

First incidence (days) 593 441 436 589 

Life table test P=0.059 P=0.178 P=0.280 P=0.052 

Logistic regression test P=0.232 P=0.110 P=0.295 P=0.160 

Cochran-Armitage test P=0.407 

Fisher exact test P=0.247 P=0.326 P=0.437 

(T)Terminal sacrifice 

a Number of neoplasm-bearing animals/number of animals examined. Denominator is number of animals examined microscopically for liver, lung, ovary, 

pituitary gland, and uterus; for other tissues, denominator is number of animals necropsied. b Kaplan-Meier estimated neoplasm incidence at the end of the study after adjustment for intercurrent mortality 

Observed incidence at terminal kill 

d	 Beneath the vehicle control incidence are the P values associated with the trend test. Beneath the dosed group incidence are the P values corresponding to 

pairwise comparisons between the vehicle controls and that dosed group. The life table test regards neoplasms in animals dying prior to terminal kill as being 

(directly or indirectly) the cause of death. The logistic regression test regards these lesions as nonfatal. The Cochran-Armitage and Fisher exact tests compare 

directly the overall incidence rates. For all tests, a negative trend or a lower incidence in a dose group is indicated by N. e Not applicable; no neoplasms in animal group f Value of statistic cannot be computed. 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

178 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE F3 

Summary of the Incidence of Nonneoplastic Lesions in Female Mice in the 2-Year Gavage Study 

of AZT/500 U "-Interferon A/Da 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Disposition Summary 

Animals initially in study 50 50 50 50 

Early deaths 

Accidental deaths 3 4 2 4 

Moribund 7 8 11 12 

Natural deaths 7 6 5 9 

Survivors 

Terminal sacrifice 33 32 32 24 

Missing 1 

Animals examined microscopically 50 50 50 49 

Alimentary System 

Esophagus (50) (50) (50) (48) 

Inflammation, chronic 1 (2%) 

Perforation 2 (4%) 2 (4%) 1 (2%) 2 (4%) 

Intestine large, colon (50) (48) (50) (49) 

Parasite metazoan 1 (2%) 

Intestine large, rectum (50) (50) (50) (49) 

Parasite metazoan 1 (2%) 

Intestine large, cecum (50) (49) (50) (48) 

Edema 1 (2%) 2 (4%) 1 (2%) 

Parasite metazoan 1 (2%) 2 (4%) 

Intestine small, duodenum (48) (49) (48) (48) 

Erosion 1 (2%) 

Ulcer 1 (2%) 

Intestine small, jejunum (50) (49) (49) (49) 

Peyer’s patch, hyperplasia, lymphoid 1 (2%) 

Intestine small, ileum (49) (49) (46) (47) 

Peyer’s patch, hyperplasia, lymphoid 1 (2%) 1 (2%) 

Liver (50) (50) (50) (49) 

Angiectasis 1 (2%) 

Basophilic focus 1 (2%) 3 (6%) 

Clear cell focus 2 (4%) 

Eosinophilic focus 5 (10%) 1 (2%) 5 (10%) 3 (6%) 

Hematopoietic cell proliferation 3 (6%) 3 (6%) 4 (8%) 4 (8%) 

Inflammation, chronic 6 (12%) 6 (12%) 5 (10%) 7 (14%) 

Mixed cell focus 2 (4%) 1 (2%) 1 (2%) 

Necrosis, focal 4 (8%) 6 (12%) 8 (16%) 

Pigmentation, focal 1 (2%) 1 (2%) 

Vacuolization cytoplasmic 1 (2%) 2 (4%) 

Bile duct, hyperplasia 1 (2%) 

Centrilobular, necrosis 1 (2%) 

Centrilobular, necrosis, focal 1 (2%) 

Hepatocyte, karyomegaly 1 (2%) 1 (2%) 

Hepatocyte, mixed cell focus 1 (2%) 

Mesentery (10) (11) (9) (6) 

Fat, necrosis 8 (80%) 9 (82%) 7 (78%) 3 (50%) 

Pancreas (50) (50) (50) (49) 

Cyst 3 (6%) 1 (2%) 

Acinus, atrophy, diffuse 3 (6%) 

a Number of animals examined microscopically at the site and the number of animals with lesion 
 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 179 

TABLE F3 

Summary of the Incidence of Nonneoplastic Lesions in Female Mice in the 2-Year Gavage Study 

of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Alimentary System (continued) 

Salivary glands (50) (49) (49) (48) 

Inflammation, chronic 2 (4%) 5 (10%) 2 (4%) 3 (6%) 

Stomach, forestomach (50) (50) (50) (49) 

Edema 1 (2%) 

Epithelium, hyperplasia 2 (4%) 2 (4%) 2 (4%) 1 (2%) 

Stomach, glandular (50) (50) (50) (49) 

Edema 2 (4%) 1 (2%) 

Erosion 3 (6%) 

Cardiovascular System 

Blood vessel (50) (50) (50) (49) 

Hypertrophy 1 (2%) 

Inflammation, chronic 1 (2%) 

Heart (50) (50) (50) (49) 

Inflammation, chronic 1 (2%) 2 (4%) 1 (2%) 1 (2%) 

Mineralization 3 (6%) 

Thrombosis 2 (4%) 

Endocrine System 

Adrenal cortex (49) (50) (50) (49) 

Accessory adrenal cortical nodule 7 (14%) 5 (10%) 6 (12%) 5 (10%) 

Hyperplasia, focal 1 (2%) 2 (4%) 1 (2%) 3 (6%) 

Hypertrophy, focal 2 (4%) 

Capsule, hyperplasia, focal 2 (4%) 1 (2%) 2 (4%) 

Adrenal medulla (49) (49) (49) (48) 

Hyperplasia 2 (4%) 1 (2%) 1 (2%) 

Islets, pancreatic (50) (50) (50) (49) 

Hyperplasia 1 (2%) 2 (4%) 3 (6%) 2 (4%) 

Parathyroid gland (45) (43) (46) (44) 

Cyst 3 (7%) 1 (2%) 

Pituitary gland (50) (47) (48) (47) 

Pars distalis, angiectasis 3 (6%) 1 (2%) 

Pars distalis, hyperplasia, focal 3 (6%) 9 (19%) 5 (10%) 4 (9%) 

Thyroid gland (50) (50) (50) (49) 

Degeneration, cystic, focal 12 (24%) 15 (30%) 13 (26%) 9 (18%) 

Follicle, cyst 8 (16%) 4 (8%) 7 (14%) 9 (18%) 

Follicular cell, hyperplasia 27 (54%) 16 (32%) 22 (44%) 13 (27%) 

General Body System 

None 

Genital System 

Ovary (49) (49) (49) (49) 

Angiectasis 5 (10%) 10 (20%) 7 (14%) 6 (12%) 

Cyst 9 (18%) 6 (12%) 13 (27%) 7 (14%) 

Hyperplasia, tubular 1 (2%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

180 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE F3 

Summary of the Incidence of Nonneoplastic Lesions in Female Mice in the 2-Year Gavage Study 

of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Genital System (continued) 

Uterus (50) (50) (50) (49) 

Angiectasis 1 (2%) 1 (2%) 2 (4%) 

Hydrometra 14 (28%) 17 (34%) 19 (38%) 25 (51%) 

Inflammation, suppurative 2 (4%) 2 (4%) 2 (4%) 3 (6%) 

Endometrium, hyperplasia, cystic 35 (70%) 41 (82%) 36 (72%) 31 (63%) 

Vagina (49) (44) (48) (48) 

Epithelium, hyperplasia 4 (9%) 6 (13%) 11 (23%) 

Epithelium, hyperplasia, atypical 2 (4%) 1 (2%) 

Hematopoietic System 

Bone marrow (50) (50) (50) (49) 

Hyperplasia 10 (20%) 14 (28%) 16 (32%) 14 (29%) 

Myelofibrosis 2 (4%) 1 (2%) 2 (4%) 3 (6%) 

Lymph node (4) (8) (10) (10) 

Iliac, hemorrhage 1 (10%) 

Iliac, hyperplasia, lymphoid 2 (20%) 

Inguinal, hyperplasia, lymphoid 1 (10%) 1 (10%) 

Mediastinal, hematopoietic cell proliferation 1 (10%) 

Mediastinal, hyperplasia, lymphoid 1 (25%) 1 (10%) 1 (10%) 

Renal, hemorrhage 1 (10%) 

Renal, hyperplasia, lymphoid 1 (10%) 

Lymph node, mandibular (49) (45) (46) (48) 

Hematopoietic cell proliferation 1 (2%) 1 (2%) 

Hemorrhage 2 (4%) 

Hyperplasia, lymphoid 2 (4%) 5 (11%) 4 (9%) 2 (4%) 

Pigmentation 7 (14%) 8 (18%) 12 (26%) 14 (29%) 

Lymph node, mesenteric (50) (47) (49) (49) 

Hematopoietic cell proliferation 3 (6%) 1 (2%) 3 (6%) 

Hemorrhage 5 (10%) 5 (11%) 2 (4%) 2 (4%) 

Hyperplasia, lymphoid 1 (2%) 6 (13%) 8 (16%) 2 (4%) 

Spleen (50) (50) (50) (49) 

Hematopoietic cell proliferation 25 (50%) 28 (56%) 26 (52%) 30 (61%) 

Hyperplasia, lymphoid 6 (12%) 17 (34%) 10 (20%) 3 (6%) 

Pigmentation 1 (2%) 2 (4%) 3 (6%) 2 (4%) 

Thymus (47) (46) (46) (45) 

Atrophy 1 (2%) 3 (7%) 2 (4%) 

Hyperplasia, lymphoid 1 (2%) 

Integumentary System 

Mammary gland (50) (49) (50) (49) 

Hyperplasia 5 (10%) 7 (14%) 2 (4%) 

Skin (49) (50) (50) (49) 

Ulcer 1 (2%) 

Epidermis, hyperplasia, focal 1 (2%) 1 (2%) 

Subcutaneous tissue, edema 1 (2%) 3 (6%) 1 (2%) 

Subcutaneous tissue, hemorrhage, focal 1 (2%) 

Subcutaneous tissue, inflammation,

 chronic, focal 1 (2%) 1 (2%) 1 (2%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 181 

TABLE F3 

Summary of the Incidence of Nonneoplastic Lesions in Female Mice in the 2-Year Gavage Study 

of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Musculoskeletal System 

Bone (49) (50) (50) (49) 

Hyperostosis 40 (82%) 39 (78%) 41 (82%) 34 (69%) 

Femur, osteopetrosis 1 (2%) 3 (6%) 

Skeletal muscle (50) (50) (50) (49) 

Hemorrhage 1 (2%) 

Nervous System 

Brain (50) (50) (50) (49) 

Atrophy, focal 4 (8%) 1 (2%) 3 (6%) 1 (2%) 

Developmental malformation 1 (2%) 

Hydrocephalus 1 (2%) 1 (2%) 

Necrosis 1 (2%) 1 (2%) 1 (2%) 

Peripheral nerve (2) (1) (6) (3) 

Atrophy 1 (100%) 1 (17%) 1 (33%) 

Respiratory System 

Lung (50) (50) (50) (49) 

Hemorrhage 5 (10%) 2 (4%) 2 (4%) 1 (2%) 

Infiltration cellular, histiocyte 2 (4%) 2 (4%) 1 (2%) 

Inflammation, chronic 3 (6%) 1 (2%) 

Inflammation, suppurative 2 (4%) 1 (2%) 1 (2%) 3 (6%) 

Thrombosis 1 (2%) 

Alveolar epithelium, hyperplasia 3 (6%) 2 (4%) 1 (2%) 1 (2%) 

Nose (50) (50) (50) (49) 

Inflammation, suppurative 1 (2%) 1 (2%) 2 (4%) 

Special Senses System 

None 

Urinary System 

Kidney (50) (50) (50) (49) 

Congestion 1 (2%) 

Metaplasia, focal, osseous 2 (4%) 2 (4%) 1 (2%) 

Nephropathy 36 (72%) 34 (68%) 30 (60%) 30 (61%) 

Renal tubule, accumulation, hyaline droplet 1 (2%) 1 (2%) 1 (2%) 

Renal tubule, dilatation 1 (2%) 1 (2%) 1 (2%) 

Renal tubule, hyaline droplet 1 (2%) 

Renal tubule, necrosis 1 (2%) 1 (2%) 1 (2%) 

Renal tubule, pigmentation 2 (4%) 1 (2%) 
182 AZT and AZT/"-Interferon A/D, NTP TR 469 
183 

APPENDIX G 

SUMMARY OF LESIONS IN MALE MICE 

IN THE 2-YEAR GAVAGE STUDY 

OF AZT/5,000 U "-INTERFERON A/D 

TABLE G1 Summary of the Incidence of Neoplasms in Male Mice 

in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D .................. 184 

TABLE G2 Statistical Analysis of Primary Neoplasms in Male Mice 

in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D .................. 188 

TABLE G3 Summary of the Incidence of Nonneoplastic Lesions in Male Mice 

in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D .................. 193 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

184 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE G1 

Summary of the Incidence of Neoplasms in Male Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/Da 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Disposition Summary 

Animals initially in study 50 50 50 50 

Early deaths 

Accidental deaths 1 1 

Moribund 9 11 9 6 

Natural deaths 10 3 5 10 

Survivors 

Terminal sacrifice 31 35 35 34 

Animals examined microscopically 50 50 50 50 

Alimentary System 

Intestine small, jejunum (45) (50) (46) (47) 

Carcinoma 1 (2%) 

Intestine small, ileum (45) (49) (46) (46) 

Hemangiosarcoma 1 (2%) 

Liver (50) (50) (50) (50) 

Carcinoma, metastatic, islets, pancreatic 1 (2%) 

Hemangioma 1 (2%) 

Hemangiosarcoma 1 (2%) 1 (2%) 1 (2%) 1 (2%) 

Hemangiosarcoma, multiple 1 (2%) 3 (6%) 3 (6%) 4 (8%) 

Hepatoblastoma 1 (2%) 

Hepatocellular carcinoma 15 (30%) 17 (34%) 17 (34%) 14 (28%) 

Hepatocellular carcinoma, multiple 4 (8%) 7 (14%) 1 (2%) 2 (4%) 

Hepatocellular adenoma 9 (18%) 13 (26%) 13 (26%) 13 (26%) 

Hepatocellular adenoma, multiple 10 (20%) 4 (8%) 2 (4%) 4 (8%) 

Hepatocholangiocarcinoma 1 (2%) 1 (2%) 

Histiocytic sarcoma 1 (2%) 

Mesentery (3) (5) (1) (1) 

Carcinoma, metastatic, islets, pancreatic 1 (20%) 

Hepatocholangiocarcinoma, metastatic, liver 1 (100%) 

Pancreas (48) (50) (50) (50) 

Carcinoma, metastatic, islets, pancreatic 1 (2%) 

Stomach, forestomach (49) (50) (50) (47) 

Squamous cell papilloma 1 (2%) 1 (2%) 

Stomach, glandular (49) (50) (50) (47) 

Carcinoma 1 (2%) 

Carcinoma, metastatic, islets, pancreatic 1 (2%) 

Cardiovascular System 

Heart (50) (50) (50) (50) 

Hemangiosarcoma 1 (2%) 1 (2%) 

Endocrine System 

Adrenal cortex (49) (50) (50) (50) 

Adenoma 2 (4%) 2 (4%) 

Carcinoma, metastatic, islets, pancreatic 1 (2%) 

Bilateral, capsule, adenoma 1 (2%) 

Capsule, adenoma 5 (10%) 3 (6%) 2 (4%) 
 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 185 

TABLE G1 

Summary of the Incidence of Neoplasms in Male Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Endocrine System (continued) 

Adrenal medulla (48) (50) (50) (50) 

Pheochromocytoma malignant 1 (2%) 1 (2%) 

Pheochromocytoma benign 1 (2%) 1 (2%) 

Bilateral, pheochromocytoma benign 1 (2%) 

Islets, pancreatic (48) (50) (50) (50) 

Carcinoma 1 (2%) 

Pituitary gland (47) (43) (48) (43) 

Pars intermedia, adenoma 1 (2%) 

Thyroid gland (50) (50) (50) (49) 

Bilateral, follicular cell, adenoma 1 (2%) 

Follicular cell, adenoma 5 (10%) 2 (4%) 1 (2%) 5 (10%) 

Follicular cell, carcinoma 1 (2%) 

General Body System 

None 

Genital System 

Epididymis (50) (50) (50) (50) 

Seminal vesicle (50) (50) (50) (49) 

Testes (50) (50) (50) (50) 

Interstitial cell, adenoma 1 (2%) 1 (2%) 

Hematopoietic System 

Bone marrow (50) (50) (50) (50) 

Hemangiosarcoma 2 (4%) 1 (2%) 1 (2%) 

Histiocytic sarcoma 1 (2%) 

Lymph node (2) (4) (5) (2) 

Mediastinal, alveolar/bronchiolar carcinoma,

 metastatic, lung 1 (50%) 

Mediastinal, histiocytic sarcoma 1 (50%) 

Pancreatic, hepatocellular carcinoma,

 metastatic, liver 1 (50%) 

Lymph node, mesenteric (46) (50) (50) (50) 

Alveolar/bronchiolar carcinoma, metastatic,

 lung 1 (2%) 

Carcinoma, metastatic, islets, pancreatic 1 (2%) 

Histiocytic sarcoma 1 (2%) 

Spleen (48) (50) (50) (49) 

Hemangiosarcoma 1 (2%) 2 (4%) 4 (8%) 4 (8%) 

Thymus (42) (45) (46) (42) 

Alveolar/bronchiolar carcinoma, metastatic,

 lung 1 (2%) 

Carcinoma, metastatic, islets, pancreatic 1 (2%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

186 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE G1 

Summary of the Incidence of Neoplasms in Male Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Integumentary System 

Skin (50) (49) (50) (50) 

Subcutaneous tissue, fibrosarcoma 2 (4%) 

Subcutaneous tissue, hemangiosarcoma 1 (2%) 

Subcutaneous tissue, hepatocellular

 carcinoma, metastatic, liver 1 (2%) 

Musculoskeletal System 

Skeletal muscle (50) (50) (50) (50) 

Fibrosarcoma, metastatic, skin 1 (2%) 

Nervous System 

None 

Respiratory System 

Lung (50) (50) (50) (50) 

Alveolar/bronchiolar adenoma 6 (12%) 7 (14%) 5 (10%) 6 (12%) 

Alveolar/bronchiolar adenoma, multiple 1 (2%) 2 (4%) 

Alveolar/bronchiolar carcinoma 2 (4%) 4 (8%) 3 (6%) 

Carcinoma, metastatic, harderian gland 1 (2%) 

Carcinoma, metastatic, islets, pancreatic 1 (2%) 

Fibrosarcoma 1 (2%) 

Fibrosarcoma, metastatic, skin 1 (2%) 

Hepatocellular carcinoma, metastatic, liver 6 (12%) 3 (6%) 1 (2%) 3 (6%) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 

Special Senses System 

Ear (1) (1) (1) 

External ear, histiocytic sarcoma 1 (100%) 

Eye (1) (6) (2) 

Retrobulbar, fibrosarcoma 1 (17%) 

Harderian gland (4) (9) (4) (4) 

Adenoma 3 (75%) 9 (100%) 3 (75%) 4 (100%) 

Carcinoma 1 (25%) 

Urinary System 

Kidney (49) (50) (50) (50) 

Carcinoma, metastatic, islets, pancreatic 1 (2%) 

Carcinoma, metastatic, liver 1 (2%) 

Hepatocellular carcinoma, metastatic, liver 1 (2%) 

Histiocytic sarcoma 1 (2%) 

Systemic Lesions 

Multiple organsb (50) (50) (50) (50) 

Histiocytic sarcoma 1 (2%) 1 (2%) 

Lymphoma malignant 2 (4%) 3 (6%) 6 (12%) 3 (6%) 
187 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE G1 

Summary of the Incidence of Neoplasms in Male Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Neoplasm Summary 

Total animals with primary neoplasmsc 41 44 40 43 

Total primary neoplasms 67 91 73 71 

Total animals with benign neoplasms 28 30 26 31 

Total benign neoplasms 37 45 31 39 

Total animals with malignant neoplasms 28 34 29 26 

Total malignant neoplasms 30 46 42 32 

Total animals with metastatic neoplasms 7 5 2 5 

Total metastatic neoplasms 7 16 2 9 

a Number of animals examined microscopically at the site and the number of animals with neoplasm b Number of animals with any tissue examined microscopically 

Primary neoplasms: all neoplasms except metastatic neoplasms 
188 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE G2 

Statistical Analysis of Primary Neoplasms in Male Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Adrenal Cortex: Adenoma 

Overall ratea 

Adjusted rateb 2/49 (4%) 

6.2% 

6/50 (12%) 

16.2% 

3/50 (6%) 

8.6% 

4/50 (8%) 

10.7% 

Terminal ratec 1/31 (3%) 5/35 (14%) 3/35 (9%) 2/34 (6%) 

First incidence (days) 

Life table testd 

724 

P=0.472 

554 

P=0.169 

729 (T) 

P=0.552 

632 

P=0.361 

Logistic regression testd 

Cochran-Armitage testd 

Fisher exact testd 

P=0.438 

P=0.455 

P=0.134 

P=0.141 

P=0.527 

P=0.510 

P=0.333 

P=0.349 

Harderian Gland: Adenoma 

Overall rate 3/50 (6%) 9/50 (18%) 3/50 (6%) 4/50 (8%) 

Adjusted rate 7.9% 22.9% 8.6% 11.8% 

Terminal rate 1/31 (3%) 6/35 (17%) 3/35 (9%) 4/34 (12%) 

First incidence (days) 613 528 729 (T) 729 (T) 

Life table test P=0.396N P=0.082 P=0.633N P=0.527 

Logistic regression test P=0.432N P=0.064 P=0.644 P=0.484 

Cochran-Armitage test P=0.419N 

Fisher exact test P=0.061 P=0.661N P=0.500 

Harderian Gland: Adenoma or Carcinoma 

Overall rate 3/50 (6%) 9/50 (18%) 4/50 (8%) 4/50 (8%) 

Adjusted rate 7.9% 22.9% 11.0% 11.8% 

Terminal rate 1/31 (3%) 6/35 (17%) 3/35 (9%) 4/34 (12%) 

First incidence (days) 613 528 665 729 (T) 

Life table test P=0.418N P=0.082 P=0.519 P=0.527 

Logistic regression test P=0.448N P=0.064 P=0.481 P=0.484 

Cochran-Armitage test P=0.437N 

Fisher exact test P=0.061 P=0.500 P=0.500 

Liver: Hemangiosarcoma 

Overall rate 2/50 (4%) 4/50 (8%) 4/50 (8%) 5/50 (10%) 

Adjusted rate 6.3% 10.3% 10.4% 12.5% 

Terminal rate 1/31 (3%) 2/35 (6%) 2/35 (6%) 1/34 (3%) 

First incidence (days) 727 661 581 565 

Life table test P=0.202 P=0.373 P=0.380 P=0.227 

Logistic regression test P=0.154 P=0.327 P=0.319 P=0.224 

Cochran-Armitage test P=0.194 

Fisher exact test P=0.339 P=0.339 P=0.218 

Liver: Hepatocellular Adenoma 

Overall rate 19/50 (38%) 17/50 (34%) 15/50 (30%) 17/50 (34%) 

Adjusted rate 57.0% 47.0% 40.1% 43.9% 

Terminal rate 17/31 (55%) 16/35 (46%) 13/35 (37%) 13/34 (38%) 

First incidence (days) 613 661 488 498 

Life table test P=0.304N P=0.254N P=0.151N P=0.311N 

Logistic regression test P=0.433N P=0.428N P=0.322N P=0.467N 

Cochran-Armitage test P=0.381N 

Fisher exact test P=0.418N P=0.263N P=0.418N 
AZT and AZT/"-Interferon A/D, NTP TR 469 189 

TABLE G2 

Statistical Analysis of Primary Neoplasms in Male Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Liver: Hepatocellular Carcinoma 

Overall rate 19/50 (38%) 24/50 (48%) 18/50 (36%) 16/50 (32%) 

Adjusted rate 41.7% 58.0% 45.3% 38.0% 

Terminal rate 6/31 (19%) 18/35 (51%) 14/35 (40%) 9/34 (26%) 

First incidence (days) 462 528 386 526 

Life table test P=0.171N P=0.321 P=0.434N P=0.331N 

Logistic regression test P=0.139N P=0.134 P=0.561 P=0.274N 

Cochran-Armitage test P=0.169N 

Fisher exact test P=0.210 P=0.500N P=0.338N 

Liver: Hepatocellular Adenoma or Carcinoma 

Overall rate 35/50 (70%) 33/50 (66%) 28/50 (56%) 29/50 (58%) 

Adjusted rate 77.3% 78.3% 67.8% 65.5% 

Terminal rate 21/31 (68%) 26/35 (74%) 22/35 (63%) 19/34 (56%) 

First incidence (days) 462 528 386 498 

Life table test P=0.104N P=0.268N P=0.082N P=0.145N 

Logistic regression test P=0.097N P=0.460N P=0.138N P=0.150N 

Cochran-Armitage test P=0.104N 

Fisher exact test P=0.415N P=0.107N P=0.149N 

Liver: Hepatocellular Carcinoma or Hepatoblastoma 

Overall rate 20/50 (40%) 24/50 (48%) 18/50 (36%) 16/50 (32%) 

Adjusted rate 43.2% 58.0% 45.3% 38.0% 

Terminal rate 6/31 (19%) 18/35 (51%) 14/35 (40%) 9/34 (26%) 

First incidence (days) 462 528 386 526 

Life table test P=0.137N P=0.384 P=0.369N P=0.273N 

Logistic regression test P=0.104N P=0.180 P=0.533N P=0.209N 

Cochran-Armitage test P=0.130N 

Fisher exact test P=0.273 P=0.418N P=0.266N 

Liver: Hepatocellular Adenoma, Hepatocellular Carcinoma, or Hepatoblastoma 

Overall rate 36/50 (72%) 33/50 (66%) 28/50 (56%) 29/50 (58%) 

Adjusted rate 77.9% 78.3% 67.8% 65.5% 

Terminal rate 21/31 (68%) 26/35 (74%) 22/35 (63%) 19/34 (56%) 

First incidence (days) 462 528 386 498 

Life table test P=0.082N P=0.220N P=0.063N P=0.115N 

Logistic regression test P=0.068N P=0.375N P=0.096N P=0.105N 

Cochran-Armitage test P=0.076N 

Fisher exact test P=0.333N P=0.072N P=0.104N 

Lung: Alveolar/bronchiolar Adenoma 

Overall rate 6/50 (12%) 8/50 (16%) 7/50 (14%) 6/50 (12%) 

Adjusted rate 16.2% 22.9% 20.0% 16.1% 

Terminal rate 3/31 (10%) 8/35 (23%) 7/35 (20%) 4/34 (12%) 

First incidence (days) 474 729 (T) 729 (T) 600 

Life table test P=0.448N P=0.458 P=0.567 P=0.592N 

Logistic regression test P=0.511N P=0.371 P=0.467 P=0.615N 

Cochran-Armitage test P=0.486N 

Fisher exact test P=0.387 P=0.500 P=0.620N 
190 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE G2 

Statistical Analysis of Primary Neoplasms in Male Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Lung: Alveolar/bronchiolar Carcinoma 

Overall rate 2/50 (4%) 4/50 (8%) 3/50 (6%) 0/50 (0%) 

Adjusted rate 6.5% 10.6% 7.9% 0.0% 

Terminal rate 2/31 (6%) 2/35 (6%) 2/35 (6%) 0/34 (0%) e First incidence (days) 729 (T) 683 562 —

Life table test P=0.127N P=0.386 P=0.540 P=0.218N 

Logistic regression test P=0.143N P=0.328 P=0.487 P=0.218N 

Cochran-Armitage test P=0.137N 

Fisher exact test P=0.339 P=0.500 P=0.247N 

Lung: Alveolar/bronchiolar Adenoma or Carcinoma 

Overall rate 8/50 (16%) 12/50 (24%) 10/50 (20%) 6/50 (12%) 

Adjusted rate 22.2% 32.2% 27.4% 16.1% 

Terminal rate 5/31 (16%) 10/35 (29%) 9/35 (26%) 4/34 (12%) 

First incidence (days) 474 683 562 600 

Life table test P=0.198N P=0.307 P=0.479 P=0.357N 

Logistic regression test P=0.248N P=0.208 P=0.361 P=0.388N 

Cochran-Armitage test P=0.228N 

Fisher exact test P=0.227 P=0.398 P=0.387N 

Spleen: Hemangiosarcoma 

Overall rate 1/48 (2%) 2/50 (4%) 4/50 (8%) 4/49 (8%) 

Adjusted rate 3.2% 5.2% 10.4% 9.9% 

Terminal rate 1/31 (3%) 1/35 (3%) 2/35 (6%) 1/34 (3%) 

First incidence (days) 729 (T) 661 581 565 

Life table test P=0.117 P=0.525 P=0.210 P=0.179 

Logistic regression test P=0.114 P=0.507 P=0.181 P=0.188 

Cochran-Armitage test P=0.115 

Fisher exact test P=0.515 P=0.194 P=0.187 

Thyroid Gland (Follicular Cell): Adenoma 

Overall rate 6/50 (12%) 2/50 (4%) 1/50 (2%) 5/49 (10%)
 

Adjusted rate 17.2% 5.7% 2.9% 14.7%
 

Terminal rate 4/31 (13%) 2/35 (6%) 1/35 (3%) 5/34 (15%)
 

First incidence (days) 677 729 (T) 729 (T) 729 (T)
 

Life table test P=0.510N P=0.112N P=0.051N P=0.454N
 

Logistic regression test P=0.563N P=0.139N P=0.065N P=0.533N
 

Cochran-Armitage test P=0.549N
 

Fisher exact test P=0.134N P=0.056N P=0.514N
 

Thyroid Gland (Follicular Cell): Adenoma or Carcinoma 

Overall rate 6/50 (12%) 3/50 (6%) 1/50 (2%) 5/49 (10%)
 

Adjusted rate 17.2% 8.6% 2.9% 14.7%
 

Terminal rate 4/31 (13%) 3/35 (9%) 1/35 (3%) 5/34 (15%)
 

First incidence (days) 677 729 (T) 729 (T) 729 (T)
 

Life table test P=0.453N P=0.203N P=0.051N P=0.454N
 

Logistic regression test P=0.508N P=0.249N P=0.065N P=0.533N
 

Cochran-Armitage test P=0.494N
 

Fisher exact test P=0.243N P=0.056N P=0.514N
 
AZT and AZT/"-Interferon A/D, NTP TR 469 191 

TABLE G2 

Statistical Analysis of Primary Neoplasms in Male Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

All Organs: Hemangiosarcoma 

Overall rate 5/50 (10%) 5/50 (10%) 4/50 (8%) 6/50 (12%) 

Adjusted rate 15.6% 13.0% 10.4% 15.2% 

Terminal rate 4/31 (13%) 3/35 (9%) 2/35 (6%) 2/34 (6%) 

First incidence (days) 727 661 581 565 

Life table test P=0.452 P=0.571N P=0.440N P=0.526 

Logistic regression test P=0.426 P=0.619 P=0.530N P=0.493 

Cochran-Armitage test P=0.437 

Fisher exact test P=0.630N P=0.500N P=0.500 

All Organs: Malignant Lymphoma 

Overall rate 2/50 (4%) 3/50 (6%) 6/50 (12%) 3/50 (6%) 

Adjusted rate 4.7% 7.7% 14.9% 7.8% 

Terminal rate 0/31 (0%) 2/35 (6%) 2/35 (6%) 1/34 (3%) 

First incidence (days) 670 473 605 586 

Life table test P=0.384 P=0.516 P=0.140 P=0.487 

Logistic regression test P=0.395 P=0.526 P=0.054 P=0.309 

Cochran-Armitage test P=0.389 

Fisher exact test P=0.500 P=0.134 P=0.500 

All Organs: Benign Neoplasms 

Overall rate 28/50 (56%) 30/50 (60%) 26/50 (52%) 31/50 (62%) 

Adjusted rate 71.1% 74.6% 68.1% 73.5% 

Terminal rate 20/31 (65%) 25/35 (71%) 23/35 (66%) 23/34 (68%) 

First incidence (days) 474 528 488 498 

Life table test P=0.464 P=0.534N P=0.254N P=0.484 

Logistic regression test P=0.292 P=0.358 P=0.536N P=0.282 

Cochran-Armitage test P=0.358 

Fisher exact test P=0.420 P=0.421N P=0.342 

All Organs: Malignant Neoplasms 

Overall rate 28/50 (56%) 34/50 (68%) 29/50 (58%) 26/50 (52%) 

Adjusted rate 58.1% 72.3% 64.4% 55.3% 

Terminal rate 11/31 (35%) 22/35 (63%) 19/35 (54%) 13/34 (38%) 

First incidence (days) 462 439 386 517 

Life table test P=0.251N P=0.323 P=0.538N P=0.399N 

Logistic regression test P=0.182N P=0.064 P=0.273 P=0.451N 

Cochran-Armitage test P=0.226N 

Fisher exact test P=0.151 P=0.500 P=0.421N 
192 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE G2 

Statistical Analysis of Primary Neoplasms in Male Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

All Organs: Benign or Malignant Neoplasms 

Overall rate 41/50 (82%) 44/50 (88%) 40/50 (80%) 43/50 (86%) 

Adjusted rate 83.7% 91.7% 87.0% 89.6% 

Terminal rate 23/31 (74%) 31/35 (89%) 29/35 (83%) 29/34 (85%) 

First incidence (days) 462 439 386 498 

Life table test P=0.497N P=0.554N P=0.337N P=0.560N 

Logistic regression test P=0.483 P=0.247 P=0.390 P=0.370 

Cochran-Armitage test P=0.448 

Fisher exact test P=0.288 P=0.500N P=0.393 

(T)Terminal sacrifice 

a Number of neoplasm-bearing animals/number of animals examined. Denominator is number of animals examined microscopically for adrenal gland, liver, 

lung, spleen, and thyroid gland; for other tissues, denominator is number of animals necropsied. b	 Kaplan-Meier estimated neoplasm incidence at the end of the study after adjustment for intercurrent mortality 

Observed incidence at terminal kill 

d	 Beneath the vehicle control incidence are the P values associated with the trend test. Beneath the dosed group incidence are the P values corresponding to 

pairwise comparisons between the vehicle controls and that dosed group. The life table test regards neoplasms in animals dying prior to terminal kill as being 

(directly or indirectly) the cause of death. The logistic regression test regards these lesions as nonfatal. The Cochran-Armitage and Fisher exact tests compare 

directly the overall incidence rates. For all tests, a negative trend or a lower incidence in a dose group is indicated by N. e Not applicable; no neoplasms in animal group 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 193 

TABLE G3 

Summary of the Incidence of Nonneoplastic Lesions in Male Mice in the 2-Year Gavage Study 

of AZT/5,000 U "-Interferon A/Da 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Disposition Summary 

Animals initially in study 50 50 50 50 

Early deaths 

Accidental deaths 1 1 

Moribund 9 11 9 6 

Natural deaths 10 3 5 10 

Survivors 

Terminal sacrifice 31 35 35 34 

Animals examined microscopically 50 50 50 50 

Alimentary System 

Esophagus (50) (50) (50) (50) 

Necrosis 1 (2%) 

Perforation 1 (2%) 

Muscularis, inflammation, chronic 1 (2%) 1 (2%) 

Gallbladder (44) (46) (45) (42) 

Inflammation, chronic 1 (2%) 

Intestine small, duodenum (46) (48) (48) (46) 

Hyperplasia, adenomatous 1 (2%) 

Liver (50) (50) (50) (50) 

Basophilic focus 1 (2%) 1 (2%) 

Clear cell focus 1 (2%) 6 (12%) 2 (4%) 2 (4%) 

Congestion 1 (2%) 

Degeneration, cystic 1 (2%) 

Eosinophilic focus 6 (12%) 7 (14%) 3 (6%) 3 (6%) 

Hemorrhage 2 (4%) 1 (2%) 

Inflammation, chronic 45 (90%) 43 (86%) 38 (76%) 41 (82%) 

Inflammation, focal 1 (2%) 

Mixed cell focus 3 (6%) 3 (6%) 6 (12%) 4 (8%) 

Necrosis, focal 2 (4%) 2 (4%) 3 (6%) 8 (16%) 

Pigmentation, focal 1 (2%) 

Vacuolization cytoplasmic 6 (12%) 7 (14%) 2 (4%) 6 (12%) 

Bile duct, cyst 1 (2%) 1 (2%) 2 (4%) 

Bile duct, hyperplasia 29 (58%) 31 (62%) 33 (66%) 29 (58%) 

Centrilobular, necrosis 1 (2%) 

Hepatocyte, karyomegaly 37 (74%) 32 (64%) 31 (62%) 32 (64%) 

Mesentery (3) (5) (1) (1) 

Inflammation, chronic 1 (20%) 

Thrombosis 1 (20%) 

Artery, inflammation, chronic 1 (33%) 1 (20%) 

Fat, necrosis 1 (33%) 1 (100%) 

Pancreas (48) (50) (50) (50) 

Inflammation, chronic 1 (2%) 

Acinus, atrophy, diffuse 1 (2%) 

Acinus, atrophy, focal 2 (4%) 

Duct, cyst 1 (2%) 1 (2%) 

Stomach, forestomach (49) (50) (50) (47) 

Cyst 1 (2%) 1 (2%) 

Diverticulum 1 (2%) 

Edema 1 (2%) 

Inflammation, chronic 1 (2%) 

Ulcer 3 (6%) 

Epithelium, hyperplasia 3 (6%) 2 (4%) 5 (10%) 3 (6%) 

a Number of animals examined microscopically at the site and the number of animals with lesion 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

194 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE G3 

Summary of the Incidence of Nonneoplastic Lesions in Male Mice in the 2-Year Gavage Study 

of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Alimentary System (continued) 

Stomach, glandular (49) (50) (50) (47) 

Edema 1 (2%) 

Erosion 1 (2%) 

Hyperplasia, adenomatous 1 (2%) 

Inflammation, chronic 1 (2%) 

Mineralization 1 (2%) 1 (2%) 3 (6%) 2 (4%) 

Necrosis 1 (2%) 

Glands, degeneration, cystic, focal 4 (8%) 4 (8%) 1 (2%) 

Tooth (2) (2) (2) (1) 

Developmental malformation 2 (100%) 2 (100%) 1 (50%) 1 (100%) 

Cardiovascular System 

Blood vessel (50) (49) (50) (49) 

Inflammation, chronic 1 (2%) 

Heart (50) (50) (50) (50) 

Inflammation, chronic, focal 1 (2%) 

Mineralization 2 (4%) 

Thrombosis 1 (2%) 

Artery, inflammation, chronic 1 (2%) 1 (2%) 

Endocrine System 

Adrenal cortex (49) (50) (50) (50) 

Cytoplasmic alteration, focal 3 (6%) 10 (20%) 6 (12%) 18 (36%) 

Hyperplasia, focal 2 (4%) 7 (14%) 3 (6%) 

Hypertrophy, focal 7 (14%) 11 (22%) 9 (18%) 11 (22%) 

Capsule, hyperplasia, focal 2 (4%) 2 (4%) 3 (6%) 2 (4%) 

Adrenal medulla (48) (50) (50) (50) 

Hyperplasia 1 (2%) 

Islets, pancreatic (48) (50) (50) (50) 

Hyperplasia 2 (4%) 1 (2%) 1 (2%) 

Parathyroid gland (50) (45) (48) (46) 

Cyst 3 (6%) 1 (2%) 1 (2%) 

Pituitary gland (47) (43) (48) (43) 

Pars distalis, cyst 1 (2%) 3 (6%) 2 (5%) 

Pars distalis, hyperplasia, focal 1 (2%) 1 (2%) 1 (2%) 

Thyroid gland (50) (50) (50) (49) 

Degeneration, cystic, focal 7 (14%) 11 (22%) 14 (28%) 10 (20%) 

Inflammation, chronic, focal 1 (2%) 

C-cell, hyperplasia 1 (2%) 

Follicle, cyst 5 (10%) 5 (10%) 6 (12%) 6 (12%) 

Follicular cell, hyperplasia 13 (26%) 14 (28%) 7 (14%) 10 (20%) 

General Body System 

None 

Genital System 

Epididymis (50) (50) (50) (50) 

Granuloma sperm 2 (4%) 

Inflammation, suppurative 1 (2%) 

Spermatocele 1 (2%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 195 

TABLE G3 

Summary of the Incidence of Nonneoplastic Lesions in Male Mice in the 2-Year Gavage Study 

of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Genital System (continued) 

Preputial gland (50) (49) (47) (50) 

Degeneration, cystic 44 (88%) 41 (84%) 42 (89%) 48 (96%) 

Inflammation, chronic 2 (4%) 2 (4%) 

Prostate (49) (49) (50) (49) 

Inflammation, chronic 1 (2%) 

Seminal vesicle (50) (50) (50) (49) 

Angiectasis 1 (2%) 

Inflammation, chronic 1 (2%) 1 (2%) 

Testes (50) (50) (50) (50) 

Germinal epithelium, degeneration 1 (2%) 

Hematopoietic System 

Bone marrow (50) (50) (50) (50) 

Hyperplasia 1 (2%) 7 (14%) 1 (2%) 1 (2%) 

Lymph node (2) (4) (5) (2) 

Mediastinal, hyperplasia, lymphoid 1 (20%) 

Mediastinal, necrosis 1 (20%) 

Pancreatic, hyperplasia, lymphoid 1 (25%) 

Lymph node, mandibular (45) (46) (44) (47) 

Hyperplasia, lymphoid 1 (2%) 2 (4%) 

Lymph node, mesenteric (46) (50) (50) (50) 

Ectasia 3 (6%) 1 (2%) 2 (4%) 

Hemorrhage 17 (37%) 21 (42%) 12 (24%) 13 (26%) 

Hyperplasia, histiocytic 1 (2%) 

Hyperplasia, lymphoid 3 (7%) 1 (2%) 1 (2%) 3 (6%) 

Inflammation, chronic 2 (4%) 

Spleen (48) (50) (50) (49) 

Angiectasis 1 (2%) 

Congestion 3 (6%) 1 (2%) 2 (4%) 

Depletion cellular 2 (4%) 

Fibrosis, focal 1 (2%) 

Hematopoietic cell proliferation 18 (38%) 16 (32%) 12 (24%) 14 (29%) 

Hyperplasia, lymphoid 3 (6%) 3 (6%) 

Necrosis, focal 1 (2%) 

Capsule, fibrosis 1 (2%) 

Thymus (42) (45) (46) (42) 

Atrophy 3 (7%) 2 (4%) 3 (7%) 

Cyst 2 (5%) 6 (13%) 8 (17%) 7 (17%) 

Necrosis 1 (2%) 1 (2%) 

Integumentary System 

Skin (50) (49) (50) (50) 

Cyst epithelial inclusion 2 (4%) 

Edema 1 (2%) 1 (2%) 7 (14%) 3 (6%) 

Infiltration cellular, mast cell 1 (2%) 

Inflammation, chronic, focal 1 (2%) 3 (6%) 1 (2%) 2 (4%) 

Ulcer 2 (4%) 

Subcutaneous tissue, edema 1 (2%) 

Subcutaneous tissue, foreign body 1 (2%) 

Subcutaneous tissue, hemorrhage 1 (2%) 

Subcutaneous tissue, inflammation, focal,

 suppurative 1 (2%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

196 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE G3 

Summary of the Incidence of Nonneoplastic Lesions in Male Mice in the 2-Year Gavage Study 

of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Musculoskeletal System 

Bone (50) (50) (50) (50) 

Hyperostosis 40 (80%) 26 (52%) 36 (72%) 31 (62%) 

Nervous System 

Brain (50) (50) (50) (49) 

Necrosis 1 (2%) 

Respiratory System 

Lung (50) (50) (50) (50) 

Congestion 2 (4%) 1 (2%) 

Foreign body 2 (4%) 

Hemorrhage 1 (2%) 1 (2%) 1 (2%) 

Hyperplasia, histiocytic 4 (8%) 1 (2%) 1 (2%) 2 (4%) 

Pigmentation 1 (2%) 

Thrombosis 1 (2%) 

Alveolar epithelium, hyperplasia 2 (4%) 2 (4%) 1 (2%) 3 (6%) 

Mediastinum, inflammation, chronic 1 (2%) 

Nose (50) (50) (50) (50) 

Hemorrhage 1 (2%) 

Inflammation, suppurative 2 (4%) 1 (2%) 

Special Senses System 

Ear (1) (1) (1) 

External ear, inflammation, chronic 1 (100%) 

Eye (1) (6) (2) 

Cataract 2 (33%) 1 (50%) 

Fibrosis 1 (17%) 

Cornea, inflammation, chronic 1 (100%) 5 (83%) 2 (100%) 

Harderian gland (4) (9) (4) (4) 

Hyperplasia, focal 1 (25%) 

Urinary System 

Kidney (49) (50) (50) (50) 

Cyst 3 (6%) 3 (6%) 2 (4%) 

Infarct 1 (2%) 5 (10%) 4 (8%) 

Metaplasia, focal, osseous 1 (2%) 

Nephropathy 49 (100%) 50 (100%) 47 (94%) 44 (88%) 

Renal tubule, accumulation, hyaline droplet 1 (2%) 

Renal tubule, dilatation 1 (2%) 

Renal tubule, hyperplasia, focal 2 (4%) 

Renal tubule, necrosis 1 (2%) 

Renal tubule, pigmentation 1 (2%) 

Urethra (3) (2) (2) (6) 

Inflammation, chronic 1 (17%) 
197 

APPENDIX H
 

SUMMARY OF LESIONS IN FEMALE MICE
 

IN THE 2-YEAR GAVAGE STUDY
 

OF AZT/5,000 U "-INTERFERON A/D
 

TABLE H1 Summary of the Incidence of Neoplasms in Female Mice 

in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D .................. 198 

TABLE H2 Statistical Analysis of Primary Neoplasms in Female Mice 

in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D .................. 203 

TABLE H3 Summary of the Incidence of Nonneoplastic Lesions in Female Mice 

in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D .................. 208 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

198 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE H1 

Summary of the Incidence of Neoplasms in Female Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/Da 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Disposition Summary 

Animals initially in study 50 50 50 50 

Early deaths 

Accidental deaths 2 1 

Moribund 8 7 6 8 

Natural deaths 5 5 6 9 

Survivors 

Died last week of study 1 

Terminal sacrifice 37 37 36 32 

Animals examined microscopically 50 50 50 50 

Alimentary System 

Gallbladder (47) (47) (48) (45) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 

Intestine large, colon (49) (49) (48) (47) 

Intestine small, jejunum (47) (46) (46) (45) 

Intestine small, ileum (47) (46) (46) (45) 

Liver (50) (50) (50) (50) 

Carcinoma, metastatic, harderian gland 1 (2%) 

Hemangiosarcoma 1 (2%) 

Hemangiosarcoma, multiple 1 (2%) 

Hepatocellular carcinoma 9 (18%) 12 (24%) 11 (22%) 10 (20%) 

Hepatocellular carcinoma, multiple 5 (10%) 3 (6%) 3 (6%) 2 (4%) 

Hepatocellular adenoma 16 (32%) 6 (12%) 11 (22%) 9 (18%) 

Hepatocellular adenoma, multiple 3 (6%) 4 (8%) 3 (6%) 6 (12%) 

Hepatocholangiocarcinoma 1 (2%) 

Histiocytic sarcoma 2 (4%) 1 (2%) 1 (2%) 1 (2%) 

Osteosarcoma, metastatic, bone 1 (2%) 

Sarcoma 1 (2%) 

Mesentery (10) (12) (9) (10) 

Fibrous histiocytoma 1 (8%) 

Hepatocholangiocarcinoma, metastatic, liver 1 (10%) 

Histiocytic sarcoma 1 (10%) 

Sarcoma 1 (11%) 

Pancreas (48) (50) (50) (49) 

Fibrous histiocytoma 1 (2%) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 

Histiocytic sarcoma 1 (2%) 

Sarcoma 1 (2%) 

Salivary glands (50) (49) (50) (48) 

Fat, hemangioma 1 (2%) 

Stomach, forestomach (50) (50) (49) (48) 

Fibrous histiocytoma 1 (2%) 

Histiocytic sarcoma 1 (2%) 

Squamous cell papilloma 1 (2%) 

Stomach, glandular (49) (50) (48) (49) 

Fibrous histiocytoma 1 (2%) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 

Histiocytic sarcoma 1 (2%) 

Tongue (1) 

Squamous cell carcinoma 1 (100%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 199 

TABLE H1 

Summary of the Incidence of Neoplasms in Female Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Cardiovascular System 

Heart (50) (50) (50) (50) 

Endocrine System 

Adrenal cortex (50) (49) (50) (49) 

Adenoma 1 (2%) 1 (2%) 

Fibrous histiocytoma 1 (2%) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 

Adrenal medulla (50) (49) (50) (49) 

Pheochromocytoma malignant 1 (2%) 

Pheochromocytoma benign 2 (4%) 1 (2%) 1 (2%) 

Islets, pancreatic (48) (49) (50) (48) 

Adenoma 1 (2%) 1 (2%) 

Pituitary gland (49) (44) (48) (44) 

Pars distalis, adenoma 8 (16%) 7 (16%) 6 (13%) 2 (5%) 

Pars intermedia, adenoma 2 (4%) 1 (2%) 

Thyroid gland (49) (50) (50) (50) 

Follicular cell, adenoma 2 (4%) 4 (8%) 6 (12%) 2 (4%) 

General Body System 

None 

Genital System 

Clitoral gland (50) (50) (50) (49) 

Carcinoma 1 (2%) 1 (2%) 1 (2%) 

Fibrosarcoma, metastatic, skin 1 (2%) 

Ovary (50) (49) (49) (50) 

Cystadenoma 3 (6%) 2 (4%) 1 (2%) 

Fibrous histiocytoma 1 (2%) 

Granulosa cell tumor benign 1 (2%) 

Hemangioma 1 (2%) 

Hemangiosarcoma 1 (2%) 

Histiocytic sarcoma 1 (2%) 1 (2%) 

Luteoma 1 (2%) 

Uterus (50) (50) (50) (50) 

Fibrous histiocytoma 1 (2%) 

Hemangiosarcoma 1 (2%) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 

Histiocytic sarcoma 1 (2%) 1 (2%) 

Leiomyosarcoma 1 (2%) 

Endometrium, carcinoma 1 (2%) 

Endometrium, polyp stromal 3 (6%) 1 (2%) 

Vagina (50) (48) (48) (50) 

Histiocytic sarcoma 1 (2%) 

Squamous cell carcinoma 5 (10%) 4 (8%) 

Squamous cell papilloma 1 (2%) 1 (2%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

200 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE H1 

Summary of the Incidence of Neoplasms in Female Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Hematopoietic System 

Bone marrow (50) (50) (50) (48) 

Hemangiosarcoma 1 (2%) 1 (2%) 

Lymph node (8) (7) (4) (6) 

Fibrosarcoma, metastatic, skin 1 (25%) 

Inguinal, fibrosarcoma, metastatic, skin 1 (13%) 1 (25%) 

Mediastinal, carcinoma, metastatic,

 uncertain primary site 1 (17%) 

Renal, hemangiosarcoma 1 (14%) 

Lymph node, mandibular (46) (46) (48) (44) 

Fibrosarcoma, metastatic, skin 1 (2%) 

Lymph node, mesenteric (48) (49) (48) (49) 

Fibrous histiocytoma 1 (2%) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 

Histiocytic sarcoma 2 (4%) 1 (2%) 

Spleen (49) (49) (49) (49) 

Fibrous histiocytoma 1 (2%) 

Hemangiosarcoma 3 (6%) 1 (2%) 1 (2%) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 

Histiocytic sarcoma 1 (2%) 

Thymus (47) (46) (48) (48) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 

Histiocytic sarcoma 1 (2%) 

Osteosarcoma, metastatic, bone 1 (2%) 

Thymoma malignant 1 (2%) 

Integumentary System 

Skin (50) (50) (50) (50) 

Subcutaneous tissue, fibrosarcoma 1 (2%) 1 (2%) 2 (4%) 1 (2%) 

Subcutaneous tissue, hemangiosarcoma 3 (6%) 

Subcutaneous tissue, sarcoma 1 (2%) 

Vulva, squamous cell papilloma 1 (2%) 

Musculoskeletal System 

Bone (50) (50) (50) (50) 

Osteosarcoma 1 (2%) 

Skeletal muscle (47) (50) (49) (50) 

Alveolar/bronchiolar carcinoma, metastatic,

 lung 1 (2%) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 

Nervous System 

None 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 201 

TABLE H1 

Summary of the Incidence of Neoplasms in Female Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Respiratory System 

Lung (50) (50) (50) (50) 

Alveolar/bronchiolar adenoma 4 (8%) 4 (8%) 2 (4%) 

Alveolar/bronchiolar carcinoma 2 (4%) 1 (2%) 3 (6%) 1 (2%) 

Carcinoma, metastatic, clitoral gland 1 (2%) 

Carcinoma, metastatic, harderian gland 1 (2%) 

Carcinoma, metastatic, uncertain primary site 1 (2%) 

Fibrosarcoma, metastatic, skin 1 (2%) 

Hepatocellular carcinoma, metastatic, liver 1 (2%) 3 (6%) 1 (2%) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 

Histiocytic sarcoma 1 (2%) 1 (2%) 1 (2%) 

Osteosarcoma, metastatic, bone 1 (2%) 

Mediastinum, alveolar/bronchiolar carcinoma 1 (2%) 

Mediastinum, carcinoma, metastatic,

 uncertain primary site 1 (2%) 

Mediastinum, fibrous histiocytoma 1 (2%) 

Mediastinum, osteosarcoma, metastatic, bone 1 (2%) 

Nose (50) (50) (50) (50) 

Carcinoma, metastatic, harderian gland 1 (2%) 

Special Senses System 

Eye (2) (1) 

Carcinoma, metastatic, harderian gland 1 (50%) 

Harderian gland (5) (2) (2) (1) 

Adenoma 3 (60%) 2 (100%) 1 (50%) 1 (100%) 

Carcinoma 1 (20%) 1 (50%) 

Urinary System 

Kidney (50) (50) (50) (49) 

Carcinoma, metastatic, uncertain primary site 1 (2%) 

Hepatocholangiocarcinoma, metastatic, liver 1 (2%) 

Histiocytic sarcoma 1 (2%) 1 (2%) 

Osteosarcoma, metastatic, bone 1 (2%) 

Urinary bladder (50) (50) (50) (50) 

Systemic Lesions 

Multiple organsb (50) (50) (50) (50) 

Histiocytic sarcoma 2 (4%) 1 (2%) 1 (2%) 1 (2%) 

Lymphoma malignant 8 (16%) 12 (24%) 8 (16%) 6 (12%) 
202 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE H1 

Summary of the Incidence of Neoplasms in Female Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Neoplasm Summary 

Total animals with primary neoplasmsc 44 40 41 39 

Total primary neoplasms 91 77 74 56 

Total animals with benign neoplasms 36 24 24 22 

Total benign neoplasms 47 33 34 27 

Total animals with malignant neoplasms 32 28 33 28 

Total malignant neoplasms 44 44 40 29 

Total animals with metastatic neoplasms 3 1 6 3 

Total metastatic neoplasms 8 1 12 17 

Total animals with malignant neoplasms 

of uncertain primary site 1 

a Number of animals examined microscopically at the site and the number of animals with neoplasm b Number of animals with any tissue examined microscopically 

Primary neoplasms: all neoplasms except metastatic neoplasms 
AZT and AZT/"-Interferon A/D, NTP TR 469 203 

TABLE H2 

Statistical Analysis of Primary Neoplasms in Female Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Adrenal Medulla: Benign or Malignant Pheochromocytoma a Overall rate 3/50 (6%) 1/49 (2%) 0/50 (0%) 1/49 (2%) 

Adjusted rateb 7.3% 2.2% 0.0% 3.1% c Terminal rate 1/37 (3%) 0/38 (0%) 0/36 (0%) 1/32 (3%) e First incidence (days) 618 638 — 730 (T) d Life table test P=0.226N P=0.300N P=0.130N P=0.348N 

Logistic regression testd P=0.197N P=0.332N P=0.116N P=0.312N 

Cochran-Armitage testd P=0.203N 

d Fisher exact test P=0.316N P=0.121N P=0.316N 

Harderian Gland: Adenoma 

Overall rate 3/50 (6%) 2/50 (4%) 1/50 (2%) 1/50 (2%)
 

Adjusted rate 8.1% 5.3% 2.8% 3.1%
 

Terminal rate 3/37 (8%) 2/38 (5%) 1/36 (3%) 1/32 (3%)
 

First incidence (days) 730 (T) 730 (T) 730 (T) 730 (T)
 

Life table test P=0.239N P=0.488N P=0.315N P=0.358N
 

Logistic regression test P=0.239N P=0.488N P=0.315N P=0.358N
 

Cochran-Armitage test P=0.199N
 

Fisher exact test P=0.500N P=0.309N P=0.309N
 

Harderian Gland: Adenoma or Carcinoma 

Overall rate 4/50 (8%) 2/50 (4%) 2/50 (4%) 1/50 (2%)
 

Adjusted rate 10.8% 5.3% 5.6% 3.1%
 

Terminal rate 4/37 (11%) 2/38 (5%) 2/36 (6%) 1/32 (3%)
 

First incidence (days) 730 (T) 730 (T) 730 (T) 730 (T)
 

Life table test P=0.172N P=0.324N P=0.349N P=0.225N
 

Logistic regression test P=0.172N P=0.324N P=0.349N P=0.225N
 

Cochran-Armitage test P=0.137N
 

Fisher exact test P=0.339N P=0.339N P=0.181N
 

Liver: Hepatocellular Adenoma 

Overall rate 19/50 (38%) 10/50 (20%) 14/50 (28%) 15/50 (30%) 

Adjusted rate 46.0% 24.6% 36.8% 45.1% 

Terminal rate 15/37 (41%) 8/38 (21%) 12/36 (33%) 14/32 (44%) 

First incidence (days) 589 638 722 630 

Life table test P=0.495 P=0.038N P=0.229N P=0.437N 

Logistic regression test P=0.487N P=0.035N P=0.234N P=0.329N 

Cochran-Armitage test P=0.396N 

Fisher exact test P=0.038N P=0.198N P=0.263N 

Liver: Hepatocellular Carcinoma 

Overall rate 14/50 (28%) 15/50 (30%) 14/50 (28%) 12/50 (24%) 

Adjusted rate 35.7% 36.5% 34.6% 32.4% 

Terminal rate 12/37 (32%) 12/38 (32%) 10/36 (28%) 8/32 (25%) 

First incidence (days) 651 656 488 630 

Life table test P=0.496N P=0.535 P=0.553 P=0.555N 

Logistic regression test P=0.386N P=0.532 P=0.524 P=0.465N 

Cochran-Armitage test P=0.325N 

Fisher exact test P=0.500 P=0.588N P=0.410N 
204 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE H2 

Statistical Analysis of Primary Neoplasms in Female Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Liver: Hepatocellular Adenoma or Carcinoma 

Overall rate 24/50 (48%) 23/50 (46%) 23/50 (46%) 23/50 (46%) 

Adjusted rate 58.3% 54.6% 55.9% 63.4% 

Terminal rate 20/37 (54%) 19/38 (50%) 18/36 (50%) 19/32 (59%) 

First incidence (days) 589 638 488 630 

Life table test P=0.334 P=0.450N P=0.547N P=0.415 

Logistic regression test P=0.489 P=0.460N P=0.555 P=0.561 

Cochran-Armitage test P=0.471N 

Fisher exact test P=0.500N P=0.500N P=0.500N 

Lung: Alveolar/bronchiolar Adenoma 

Overall rate 4/50 (8%) 4/50 (8%) 0/50 (0%) 2/50 (4%) 

Adjusted rate 9.4% 9.9% 0.0% 5.1% 

Terminal rate 2/37 (5%) 3/38 (8%) 0/36 (0%) 1/32 (3%) 

First incidence (days) 575 592 — 557 

Life table test P=0.197N P=0.631N P=0.074N P=0.382N 

Logistic regression test P=0.144N P=0.617 P=0.048N P=0.284N 

Cochran-Armitage test P=0.162N 

Fisher exact test P=0.643N P=0.059N P=0.339N 

Lung: Alveolar/bronchiolar Carcinoma 

Overall rate 2/50 (4%) 1/50 (2%) 3/50 (6%) 1/50 (2%)
 

Adjusted rate 5.4% 2.2% 7.6% 3.1%
 

Terminal rate 2/37 (5%) 0/38 (0%) 2/36 (6%) 1/32 (3%)
 

First incidence (days) 730 (T) 598 344 730 (T)
 

Life table test P=0.521N P=0.491N P=0.484 P=0.551N
 

Logistic regression test P=0.439N P=0.512N P=0.546 P=0.551N
 

Cochran-Armitage test P=0.474N
 

Fisher exact test P=0.500N P=0.500 P=0.500N
 

Lung: Alveolar/bronchiolar Adenoma or Carcinoma 

Overall rate 6/50 (12%) 5/50 (10%) 3/50 (6%) 3/50 (6%) 

Adjusted rate 14.5% 11.8% 7.6% 8.2% 

Terminal rate 4/37 (11%) 3/38 (8%) 2/36 (6%) 2/32 (6%) 

First incidence (days) 575 592 344 557 

Life table test P=0.212N P=0.487N P=0.269N P=0.302N 

Logistic regression test P=0.134N P=0.532N P=0.193N P=0.221N 

Cochran-Armitage test P=0.162N 

Fisher exact test P=0.500N P=0.243N P=0.243N 

Ovary: Cystadenoma 

Overall rate 3/50 (6%) 0/49 (0%) 2/49 (4%) 1/50 (2%) 

Adjusted rate 8.1% 0.0% 5.6% 2.6% 

Terminal rate 3/37 (8%) 0/37 (0%) 2/36 (6%) 0/32 (0%) 

First incidence (days) 730 (T) — 730 (T) 676 

Life table test P=0.381N P=0.121N P=0.513N P=0.351N 

Logistic regression test P=0.360N P=0.121N P=0.513N P=0.324N 

Cochran-Armitage test P=0.336N 

Fisher exact test P=0.125N P=0.510N P=0.309N 
AZT and AZT/"-Interferon A/D, NTP TR 469 205 

TABLE H2 

Statistical Analysis of Primary Neoplasms in Female Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Pituitary Gland (Pars Distalis): Adenoma 

Overall rate 8/49 (16%) 7/44 (16%) 6/48 (13%) 2/44 (5%) 

Adjusted rate 19.9% 20.6% 16.6% 5.6% 

Terminal rate 5/36 (14%) 7/34 (21%) 5/35 (14%) 1/31 (3%) 

First incidence (days) 618 730 (T) 729 658 

Life table test P=0.053N P=0.536N P=0.411N P=0.075N 

Logistic regression test P=0.050N P=0.572N P=0.436N P=0.070N 

Cochran-Armitage test P=0.044N 

Fisher exact test P=0.591N P=0.403N P=0.065N 

Skin (Subcutaneous Tissue): Hemangiosarcoma 

Overall rate 3/50 (6%) 0/50 (0%) 0/50 (0%) 0/50 (0%) 

Adjusted rate 8.1% 0.0% 0.0% 0.0% 

Terminal rate 3/37 (8%) 0/38 (0%) 0/36 (0%) 0/32 (0%) 

First incidence (days) 730 (T) — — — 

Life table test P=0.054N P=0.116N P=0.126N P=0.147N 

Logistic regression test P=0.054N P=0.116N P=0.126N P=0.147N 

Cochran-Armitage test P=0.047N 

Fisher exact test P=0.121N P=0.121N P=0.121N 

Spleen: Hemangiosarcoma 

Overall rate 3/49 (6%) 0/49 (0%) 1/49 (2%) 1/49 (2%) 

Adjusted rate 8.1% 0.0% 2.4% 3.2% 

Terminal rate 3/37 (8%) 0/38 (0%) 0/36 (0%) 1/31 (3%) 

First incidence (days) 730 (T) — 648 730 (T) 

Life table test P=0.341N P=0.116N P=0.318N P=0.370N 

Logistic regression test P=0.312N P=0.116N P=0.321N P=0.370N 

Cochran-Armitage test P=0.296N 

Fisher exact test P=0.121N P=0.309N P=0.309N 

Thyroid Gland (Follicular Cell): Adenoma 

Overall rate 2/49 (4%) 4/50 (8%) 6/50 (12%) 2/50 (4%) 

Adjusted rate 5.6% 10.5% 16.7% 6.3% 

Terminal rate 2/36 (6%) 4/38 (11%) 6/36 (17%) 2/32 (6%) 

First incidence (days) 730 (T) 730 (T) 730 (T) 730 (T) 

Life table test P=0.536 P=0.361 P=0.132 P=0.652 

Logistic regression test P=0.536 P=0.361 P=0.132 P=0.652 

Cochran-Armitage test P=0.528N 

Fisher exact test P=0.349 P=0.141 P=0.684N 

Uterus: Stromal Polyp 

Overall rate 0/50 (0%) 3/50 (6%) 0/50 (0%) 1/50 (2%) 

Adjusted rate 0.0% 7.3% 0.0% 3.1% 

Terminal rate 0/37 (0%) 2/38 (5%) 0/36 (0%) 1/32 (3%) 

First incidence (days) 

Life table test 

— 

P=0.600 

598 

P=0.128 

— 

—f 730 (T) 

P=0.471 

Logistic regression test P=0.630 P=0.114 — P=0.471 

Cochran-Armitage test P=0.634 

Fisher exact test P=0.121 — P=0.500 
 

206 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE H2 

Statistical Analysis of Primary Neoplasms in Female Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Vagina: Squamous Cell Carcinoma 

Overall rate 0/50 (0%) 0/50 (0%) 5/50 (10%) 4/50 (8%)
 

Adjusted rate 0.0% 0.0% 13.9% 12.5%
 

Terminal rate 0/37 (0%) 0/38 (0%) 5/36 (14%) 4/32 (13%)
 

First incidence (days) — — 730 (T) 730 (T)
 

Life table test P=0.009 — P=0.031 P=0.046
 

Logistic regression test P=0.009 — P=0.031 P=0.046
 

Cochran-Armitage test P=0.016
 

Fisher exact test — P=0.028 P=0.059
 

Vagina: Squamous Cell Papilloma or Squamous Cell Carcinoma 

Overall rate 1/50 (2%) 1/50 (2%) 5/50 (10%) 4/50 (8%)
 

Adjusted rate 2.7% 2.6% 13.9% 12.5%
 

Terminal rate 1/37 (3%) 1/38 (3%) 5/36 (14%) 4/32 (13%)
 

First incidence (days) 733 (T) 733 (T) 730 (T) 730 (T)
 

Life table test P=0.047 P=0.747N P=0.093 P=0.136
 

Logistic regression test P=0.047 P=0.747N P=0.093 P=0.136
 

Cochran-Armitage test P=0.078
 

Fisher exact test P=0.753 P=0.102 P=0.181
 

All Organs: Hemangiosarcoma 

Overall rate 5/50 (10%) 2/50 (4%) 1/50 (2%) 1/50 (2%)
 

Adjusted rate 13.5% 5.3% 2.4% 3.1%
 

Terminal rate 5/37 (14%) 2/38 (5%) 0/36 (0%) 1/32 (3%)
 

First incidence (days) 730 (T) 730 (T) 648 730 (T)
 

Life table test P=0.078N P=0.205N P=0.112N P=0.138N
 

Logistic regression test P=0.068N P=0.205N P=0.114N P=0.138N
 

Cochran-Armitage test P=0.060N
 

Fisher exact test P=0.218N P=0.102N P=0.102N
 

All Organs: Hemangioma or Hemangiosarcoma 

Overall rate 7/50 (14%) 2/50 (4%) 1/50 (2%) 1/50 (2%)
 

Adjusted rate 18.3% 5.3% 2.4% 3.1%
 

Terminal rate 6/37 (16%) 2/38 (5%) 0/36 (0%) 1/32 (3%)
 

First incidence (days) 682 730 (T) 648 730 (T)
 

Life table test P=0.023N P=0.076N P=0.038N P=0.051N
 

Logistic regression test P=0.019N P=0.073N P=0.038N P=0.041N
 

Cochran-Armitage test P=0.016N
 

Fisher exact test P=0.080N P=0.030N P=0.030N
 

All Organs: Malignant Lymphoma 

Overall rate 8/50 (16%) 12/50 (24%) 8/50 (16%) 6/50 (12%) 

Adjusted rate 18.7% 28.3% 21.3% 15.6% 

Terminal rate 4/37 (11%) 8/38 (21%) 7/36 (19%) 2/32 (6%) 

First incidence (days) 589 592 604 557 

Life table test P=0.301N P=0.260 P=0.574 P=0.462N 

Logistic regression test P=0.215N P=0.217 P=0.585 P=0.358N 

Cochran-Armitage test P=0.204N 

Fisher exact test P=0.227 P=0.607N P=0.387N 
207 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE H2 

Statistical Analysis of Primary Neoplasms in Female Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

All Organs: Benign Neoplasms 

Overall rate 36/50 (72%) 24/50 (48%) 24/50 (48%) 22/50 (44%) 

Adjusted rate 78.1% 56.7% 61.5% 60.3% 

Terminal rate 27/37 (73%) 20/38 (53%) 21/36 (58%) 18/32 (56%) 

First incidence (days) 575 592 620 557 

Life table test P=0.063N P=0.017N P=0.029N P=0.040N 

Logistic regression test P=0.016N P=0.011N P=0.024N P=0.006N 

Cochran-Armitage test P=0.009N 

Fisher exact test P=0.012N P=0.012N P=0.004N 

All Organs: Malignant Neoplasms 

Overall rate 32/50 (64%) 28/50 (56%) 33/50 (66%) 28/50 (56%) 

Adjusted rate 69.4% 60.8% 74.7% 61.6% 

Terminal rate 23/37 (62%) 20/38 (53%) 25/36 (69%) 15/32 (47%) 

First incidence (days) 589 592 318 501 

Life table test P=0.448 P=0.262N P=0.431 P=0.517N 

Logistic regression test P=0.357N P=0.299N P=0.419 P=0.283N 

Cochran-Armitage test P=0.321N 

Fisher exact test P=0.270N P=0.500 P=0.270N 

All Organs: Benign or Malignant Neoplasms 

Overall rate 44/50 (88%) 40/50 (80%) 41/50 (82%) 39/50 (78%) 

Adjusted rate 91.7% 85.1% 91.0% 86.5% 

Terminal rate 33/37 (89%) 31/38 (82%) 32/36 (89%) 26/32 (81%) 

First incidence (days) 575 592 318 501 

Life table test P=0.432 P=0.225N P=0.445N P=0.562N 

Logistic regression test P=0.247N P=0.169N P=0.515N P=0.200N 

Cochran-Armitage test P=0.160N 

Fisher exact test P=0.207N P=0.288N P=0.143N 

(T)Terminal sacrifice 

a Number of neoplasm-bearing animals/number of animals examined. Denominator is number of animals examined microscopically for adrenal gland, liver, 

lung, ovary, pituitary gland, spleen, thyroid gland, and uterus; for other tissues, denominator is number of animals necropsied. b Kaplan-Meier estimated neoplasm incidence at the end of the study after adjustment for intercurrent mortality 

Observed incidence at terminal kill 

d	 Beneath the vehicle control incidence are the P values associated with the trend test. Beneath the dosed group incidence are the P values corresponding to 

pairwise comparisons between the vehicle controls and that dosed group. The life table test regards neoplasms in animals dying prior to terminal kill as being 

(directly or indirectly) the cause of death. The logistic regression test regards these lesions as nonfatal. The Cochran-Armitage and Fisher exact tests compare 

directly the overall incidence rates. For all tests, a negative trend or a lower incidence in a dose group is indicated by N. e Not applicable; no neoplasms in animal group f Value of statistic cannot be computed. 
 

 

 

 

 

 

 

 

 

 

 

 

 

208 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE H3 

Summary of the Incidence of Nonneoplastic Lesions in Female Mice in the 2-Year Gavage Study 

of AZT/5,000 U "-Interferon A/Da 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Disposition Summary 

Animals initially in study 50 50 50 50 

Early deaths 

Accidental deaths 2 1 

Moribund 8 7 6 8 

Natural deaths 5 5 6 9 

Survivors 

Died last week of study 1 

Terminal sacrifice 37 37 36 32 

Animals examined microscopically 50 50 50 50 

Alimentary System 

Esophagus (50) (50) (49) (49) 

Necrosis 2 (4%) 

Perforation 2 (4%) 

Muscularis, inflammation, chronic 2 (4%) 

Periesophageal tissue, inflammation, chronic 1 (2%) 

Intestine small, duodenum (48) (48) (47) (47) 

Hyperplasia, adenomatous 1 (2%) 

Intestine small, jejunum (47) (46) (46) (45) 

Hyperplasia, adenomatous 1 (2%) 

Peyer’s patch, hyperplasia, lymphoid 1 (2%) 2 (4%) 

Intestine small, ileum (47) (46) (46) (45) 

Amyloid deposition 1 (2%) 

Hyperplasia, adenomatous 1 (2%) 

Liver (50) (50) (50) (50) 

Angiectasis 1 (2%) 1 (2%) 

Basophilic focus 1 (2%) 1 (2%) 

Clear cell focus 2 (4%) 1 (2%) 

Congestion 1 (2%) 

Eosinophilic focus 4 (8%) 6 (12%) 5 (10%) 2 (4%) 

Hematopoietic cell proliferation 2 (4%) 2 (4%) 

Hemorrhage 1 (2%) 

Hyperplasia, focal, lymphoid 1 (2%) 1 (2%) 

Inflammation, chronic 10 (20%) 6 (12%) 6 (12%) 6 (12%) 

Mixed cell focus 2 (4%) 3 (6%) 2 (4%) 2 (4%) 

Necrosis, focal 2 (4%) 2 (4%) 2 (4%) 3 (6%) 

Vacuolization cytoplasmic 2 (4%) 6 (12%) 2 (4%) 3 (6%) 

Bile duct, hyperplasia 1 (2%) 

Centrilobular, necrosis 1 (2%) 

Hepatocyte, karyomegaly 1 (2%) 1 (2%) 1 (2%) 

Mesentery (10) (12) (9) (10) 

Hemorrhage 1 (10%) 2 (17%) 

Inflammation, chronic 1 (10%) 1 (8%) 

Fat, necrosis 7 (70%) 9 (75%) 5 (56%) 5 (50%) 

a Number of animals examined microscopically at the site and the number of animals with lesion 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 209 

TABLE H3 

Summary of the Incidence of Nonneoplastic Lesions in Female Mice in the 2-Year Gavage Study 

of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Alimentary System (continued) 

Pancreas (48) (50) (50) (49) 

Inflammation, chronic 1 (2%) 

Necrosis 1 (2%) 

Acinus, atrophy, diffuse 1 (2%) 1 (2%) 

Acinus, atrophy, focal 2 (4%) 1 (2%) 

Duct, cyst 1 (2%) 1 (2%) 3 (6%) 

Salivary glands (50) (49) (50) (48) 

Inflammation, chronic 1 (2%) 

Stomach, forestomach (50) (50) (49) (48) 

Cyst 1 (2%) 1 (2%) 

Inflammation, chronic 1 (2%) 1 (2%) 

Epithelium, hyperplasia 3 (6%) 2 (4%) 1 (2%) 1 (2%) 

Stomach, glandular (49) (50) (48) (49) 

Edema 1 (2%) 1 (2%) 

Mineralization 1 (2%) 

Glands, degeneration, cystic, focal 5 (10%) 1 (2%) 8 (17%) 8 (16%) 

Cardiovascular System 

Heart (50) (50) (50) (50) 

Inflammation, chronic, focal 2 (4%) 1 (2%) 

Thrombosis 1 (2%) 1 (2%) 1 (2%) 

Endocrine System 

Adrenal cortex (50) (49) (50) (49) 

Accessory adrenal cortical nodule 1 (2%) 3 (6%) 

Cyst 1 (2%) 1 (2%) 

Hyperplasia, focal 3 (6%) 4 (8%) 1 (2%) 4 (8%) 

Hypertrophy, focal 2 (4%) 2 (4%) 

Islets, pancreatic (48) (49) (50) (48) 

Hyperplasia 1 (2%) 1 (2%) 1 (2%) 

Parathyroid gland (43) (43) (45) (46) 

Cyst 1 (2%) 

Pituitary gland (49) (44) (48) (44) 

Angiectasis 4 (8%) 1 (2%) 4 (8%) 3 (7%) 

Pars distalis, cyst 1 (2%) 1 (2%) 3 (7%) 

Pars distalis, cytoplasmic alteration, focal 2 (5%) 1 (2%) 

Pars distalis, hyperplasia, focal 8 (16%) 7 (16%) 8 (17%) 8 (18%) 

Rathke’s cleft, cyst 1 (2%) 3 (7%) 

Thyroid gland (49) (50) (50) (50) 

Degeneration, cystic, focal 19 (39%) 16 (32%) 14 (28%) 12 (24%) 

Inflammation, chronic, focal 1 (2%) 

Follicle, cyst 7 (14%) 6 (12%) 9 (18%) 7 (14%) 

Follicular cell, hyperplasia 21 (43%) 19 (38%) 17 (34%) 17 (34%) 

General Body System 

None 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

210 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE H3 

Summary of the Incidence of Nonneoplastic Lesions in Female Mice in the 2-Year Gavage Study 

of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Genital System 

Clitoral gland (50) (50) (50) (49) 

Degeneration, cystic 3 (6%) 1 (2%) 3 (6%) 3 (6%) 

Inflammation, chronic 1 (2%) 

Ovary (50) (49) (49) (50) 

Cyst 10 (20%) 6 (12%) 5 (10%) 13 (26%) 

Hemorrhage 2 (4%) 1 (2%) 4 (8%) 

Mineralization 1 (2%) 1 (2%) 

Thrombosis 1 (2%) 1 (2%) 

Bilateral, cyst 1 (2%) 

Uterus (50) (50) (50) (50) 

Angiectasis 2 (4%) 

Cyst 1 (2%) 2 (4%) 

Hemorrhage 1 (2%) 1 (2%) 

Hydrometra 19 (38%) 21 (42%) 13 (26%) 15 (30%) 

Thrombosis 1 (2%) 1 (2%) 

Endometrium, hyperplasia, cystic 42 (84%) 37 (74%) 41 (82%) 45 (90%) 

Vagina (50) (48) (48) (50) 

Epithelium, hyperplasia 1 (2%) 3 (6%) 7 (15%) 12 (24%) 

Epithelium, hyperplasia, atypical 1 (2%) 1 (2%) 3 (6%) 

Hematopoietic System 

Bone marrow (50) (50) (50) (48) 

Angiectasis 1 (2%) 

Depletion cellular 2 (4%) 

Hyperplasia 1 (2%) 4 (8%) 4 (8%) 4 (8%) 

Lymph node (8) (7) (4) (6) 

Iliac, hemorrhage 1 (13%) 

Renal, hemorrhage 1 (17%) 

Lymph node, mandibular (46) (46) (48) (44) 

Hemorrhage 1 (2%) 2 (4%) 

Hyperplasia, lymphoid 2 (4%) 1 (2%) 3 (6%) 1 (2%) 

Infiltration cellular, mast cell 1 (2%) 

Lymph node, mesenteric (48) (49) (48) (49) 

Ectasia 1 (2%) 2 (4%) 

Hemorrhage 4 (8%) 2 (4%) 7 (15%) 6 (12%) 

Hyperplasia, lymphoid 1 (2%) 2 (4%) 

Spleen (49) (49) (49) (49) 

Depletion cellular 1 (2%) 1 (2%) 

Fibrosis, focal 1 (2%) 

Hematopoietic cell proliferation 23 (47%) 15 (31%) 12 (24%) 17 (35%) 

Hyperplasia, lymphoid 5 (10%) 4 (8%) 8 (16%) 3 (6%) 

Thymus (47) (46) (48) (48) 

Atrophy 3 (7%) 1 (2%) 2 (4%) 

Cyst 3 (6%) 4 (9%) 4 (8%) 2 (4%) 

Hyperplasia, lymphoid 2 (4%) 

Inflammation, granulomatous 1 (2%) 

Necrosis 1 (2%) 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AZT and AZT/"-Interferon A/D, NTP TR 469 211 

TABLE H3 

Summary of the Incidence of Nonneoplastic Lesions in Female Mice in the 2-Year Gavage Study 

of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Integumentary System 

Mammary gland (50) (50) (49) (50) 

Ectasia 1 (2%) 

Hyperplasia 1 (2%) 1 (2%) 1 (2%) 

Skin (50) (50) (50) (50) 

Cyst epithelial inclusion 1 (2%) 

Edema 3 (6%) 3 (6%) 1 (2%) 

Inflammation, chronic, focal 1 (2%) 1 (2%) 2 (4%) 

Ulcer 1 (2%) 

Subcutaneous tissue, inflammation, chronic

 active 1 (2%) 

Musculoskeletal System 

Bone (50) (50) (50) (50) 

Fibrous osteodystrophy 2 (4%) 

Hyperostosis 48 (96%) 40 (80%) 36 (72%) 43 (86%) 

Cranium, fibrous osteodystrophy 1 (2%) 

Femur, fibrous osteodystrophy 1 (2%) 2 (4%) 2 (4%) 

Femur, osteopetrosis 1 (2%) 

Skeletal muscle (47) (50) (49) (50) 

Hemorrhage, focal 1 (2%) 

Inflammation, suppurative 1 (2%) 

Regeneration 2 (4%) 

Nervous System 

Brain (50) (50) (50) (50) 

Atrophy, focal 2 (4%) 4 (8%) 1 (2%) 

Vacuolization cytoplasmic 1 (2%) 

Meninges, inflammation, chronic 1 (2%) 1 (2%) 

Spinal cord (2) (1) (4) 

Cyst epithelial inclusion 1 (50%) 1 (25%) 

Hemorrhage, focal 1 (100%) 

Respiratory System 

Lung (50) (50) (50) (50) 

Congestion 1 (2%) 2 (4%) 

Hemorrhage 3 (6%) 2 (4%) 3 (6%) 

Hyperplasia, histiocytic 2 (4%) 3 (6%) 1 (2%) 1 (2%) 

Metaplasia, osseous 1 (2%) 

Pigmentation 1 (2%) 1 (2%) 

Alveolar epithelium, hyperplasia 2 (4%) 1 (2%) 2 (4%) 

Mediastinum, inflammation, chronic 1 (2%) 

Nose (50) (50) (50) (50) 

Inflammation, suppurative 1 (2%) 1 (2%) 

Mucosa, glands, dilatation, focal 3 (6%) 
 

 

 

 

 

 

 

 

 

 

 

 

212 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE H3 

Summary of the Incidence of Nonneoplastic Lesions in Female Mice in the 2-Year Gavage Study 

of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Special Senses System 

Eye (2) (1) 

Fibrosis 1 (50%) 

Cornea, inflammation, chronic 1 (100%) 

Harderian gland (5) (2) (2) (1) 

Hyperplasia, focal 1 (20%) 

Inflammation, chronic, focal 1 (20%) 

Urinary System 

Kidney (50) (50) (50) (49) 

Congestion 1 (2%) 

Infarct 1 (2%) 1 (2%) 1 (2%) 

Metaplasia, focal, osseous 3 (6%) 2 (4%) 

Nephropathy 35 (70%) 33 (66%) 39 (78%) 33 (67%) 

Pelvis, dilatation 1 (2%) 1 (2%) 

Renal tubule, accumulation, hyaline droplet 1 (2%) 1 (2%) 

Renal tubule, atrophy 1 (2%) 

Renal tubule, dilatation 1 (2%) 1 (2%) 2 (4%) 

Renal tubule, mineralization 1 (2%) 1 (2%) 

Renal tubule, necrosis 1 (2%) 

Renal tubule, pigmentation 1 (2%) 

Urinary bladder (50) (50) (50) (50) 

Hyperplasia, lymphoid 1 (2%) 1 (2%) 
213 

APPENDIX I
 

GENETIC TOXICOLOGY
 

SALMONELLA MUTAGENICITY TEST PROTOCOL ....................................... 214
 

CHINESE HAMSTER OVARY CELL CYTOGENETICS PROTOCOLS ............................ 214
 

SHORT-TERM IN VIVO MOUSE BONE MARROW/PERIPHERAL BLOOD MICRONUCLEUS TEST PROTOCOLS . 215
 

MOUSE PERIPHERAL BLOOD MICRONUCLEUS TEST PROTOCOL ............................ 216
 

RESULTS ................................................................ 216
 

TABLE I1 Mutagenicity of AZT in Salmonella typhimurium ............................. 217
 

TABLE I2 Induction of Sister Chromatid Exchanges in Chinese Hamster Ovary Cells by AZT ..... 220
 

TABLE I3 Induction of Chromosomal Aberrations in Chinese Hamster Ovary Cells by AZT ...... 221
 

TABLE I4 Frequency of Micronuclei in Bone Marrow Cells of Male Mice Treated with AZT 

by Gavage for 3 Days ............................................... 221
 

TABLE I5 Frequency of Micronuclei in Peripheral Blood Cells of Male Mice Treated with AZT 

by Gavage for 3 Days ............................................... 222
 

TABLE I6 Frequency of Micronuclei in Peripheral Blood Cells of Male Mice Treated with AZT 

by Gavage for 14 Weeks ............................................. 222
 
 

214 AZT and AZT/"-Interferon A/D, NTP TR 469 

GENETIC TOXICOLOGY 

SALMONELLA MUTAGENICITY TEST PROTOCOL 

Testing was performed as reported by Zeiger et al. (1992). 3N-Azido-3N-deoxythymidine (AZT) was sent to 

the laboratory as a coded aliquot from Radian Corporation (Austin, TX). It was incubated with the 

Salmonella typhimurium tester strains TA97, TA98, TA100, TA102, TA104, and TA1535 either in buffer 

or S9 mix (metabolic activation enzymes and cofactors from Aroclor 1254-induced male Sprague-Dawley 

rat or Syrian hamster liver) for 20 minutes at 37E C. Top agar supplemented with L-histidine and d-biotin 

was added, and the contents of the tubes were mixed and poured onto the surfaces of minimal glucose agar 

plates. Histidine-independent mutant colonies arising on these plates were counted following incubation for 

2 days at 37E C. 

Each trial consisted of triplicate plates of concurrent positive and negative controls and at least five doses of 

AZT. All positive trials were repeated under the conditions that elicited the positive response. The high 

dose was limited by toxicity. 

In this assay, a positive response is defined as a reproducible, dose-related increase in histidine-independent 

(revertant) colonies in any one strain/activation combination. An equivocal response is defined as an 

increase in revertants that is not dose related, is not reproducible, or is not of sufficient magnitude to 

support a determination of mutagenicity. A negative response is obtained when no increase in revertant 

colonies is observed following chemical treatment. There is no minimum percentage or fold increase 

required for a chemical to be judged positive or weakly positive. 

CHINESE HAMSTER OVARY CELL CYTOGENETICS PROTOCOLS 

Testing was performed as reported by Galloway et al. (1987). AZT was sent to the laboratory as a coded 

aliquot by Radian Corporation. It was tested in cultured Chinese hamster ovary (CHO) cells for induction 

of sister chromatid exchanges (SCEs) and chromosomal aberrations (Abs), both in the presence and absence 

of Aroclor 1254-induced male Sprague-Dawley rat liver S9 and cofactor mix. Cultures were handled under 

gold lights to prevent photolysis of bromodeoxyuridine-substituted DNA. Each test consisted of concurrent 

solvent and positive controls and of at least three doses of AZT; the high dose was limited by toxicity. A 

single flask per dose was used. 

Sister Chromatid Exchange Test: In the SCE test without S9, CHO cells were incubated for 26 hours with 

AZT in McCoy’s 5A medium. Bromodeoxyuridine (BrdU) was added 2 hours after culture initiation. After 

26 hours, the medium containing AZT was removed and replaced with fresh medium plus BrdU and 

Colcemid, and incubation was continued for 2 hours. Cells were then harvested by mitotic shake-off, fixed, 

and stained with Hoechst 33258 and Giemsa. In the SCE test with S9, cells were incubated with AZT, 

serum-free medium, and S9 for 2 hours. The medium was then removed and replaced with medium 

containing serum and BrdU and no AZT, and incubation proceeded for an additional 26 hours with 

Colcemid present for the final 2 hours. Harvesting and staining were the same as for cells treated without 

S9. All slides were scored blind, and those from a single test were read by the same person. Fifty seconddivision metaphase cells were scored for frequency of SCEs/cell from each dose level, except for the 

83 μg/mL dose without S9. At this dose, SCEs were so numerous that fewer cells were scored. Because 

significant AZT-induced cell cycle delay was seen at the 250 μg/mL dose without S9, incubation time was 

lengthened to 31 hours for these cultures to ensure a sufficient number of scorable (second-division 

metaphase) cells. 
 

AZT and AZT/"-Interferon A/D, NTP TR 469 215 

Statistical analyses were conducted on the slopes of the dose-response curves and the individual dose points 

(Galloway et al., 1987). An SCE frequency 20% above the concurrent solvent control value was chosen as 

a statistically conservative positive response. The probability of this level of difference occurring by chance 

at one dose point is less than 0.01; the probability for such a chance occurrence at two dose points is less 

than 0.001. An increase of 20% or greater at any single dose was considered weak evidence of activity; 

increases at two or more doses resulted in a determination that the trial was positive. A statistically 

significant trend (P<0.005) in the absence of any responses reaching 20% above background led to a call 

of equivocal. 

Chromosomal Aberrations Test: In the Abs test without S9, cells were incubated in McCoy’s 5A medium 

with AZT for 12.5 hours; Colcemid was added and incubation continued for 2 hours. The cells were then 

harvested by mitotic shake-off, fixed, and stained with Giemsa. For the Abs test with S9, cells were treated 

with AZT and S9 for 2 hours, after which the treatment medium was removed and the cells were incubated 

for 10 hours in fresh medium with Colcemid present for the final 2 hours. Cells were harvested in the same 

manner as for the treatment without S9. 

Cells were selected for scoring on the basis of good morphology and completeness of karyotype 

(21 ± 2 chromosomes). All slides were scored blind, and those from a single test were read by the same 

person. Two hundred first-division metaphase cells were scored at each dose level. Classes of aberrations 

included simple (breaks and terminal deletions), complex (rearrangements and translocations), and other 

(pulverized cells, despiralized chromosomes, and cells containing 10 or more aberrations). 

Chromosomal aberration data are presented as percentage of cells with aberrations. To arrive at a statistical 

call for a trial, analyses were conducted on both the dose response curve and individual dose points. For a 

single trial, a statistically significant (P#0.05) difference for one dose point and a significant trend 

(P#0.015) were considered weak evidence for a positive response; significant differences for two or more 

doses indicated the trial was positive. A positive trend test in the absence of a statistically significant 

increase at any one dose resulted in an equivocal call (Galloway et al., 1987). Ultimately, the trial calls 

were based on a consideration of the statistical analyses as well as the biological information available to the 

reviewers. 

SHORT-TERM IN VIVO MOUSE BONE MARROW/ 

PERIPHERAL BLOOD MICRONUCLEUS TEST PROTOCOLS 

Preliminary range-finding studies were performed. Factors affecting dose selection included chemical 

solubility, toxicity, and the extent of cell cycle delay induced by AZT exposure. The standard threeexposure protocol is described in detail by Phillips et al. (1991). Male B6C3F1 mice were administered

AZT dissolved in corn oil by gavage (0.3 mL per mouse) three times at 24-hour intervals. Solvent control 

animals received 0.3 mL of corn oil alone. The positive control mice received injections of 

dimethylbenzanthracene (12.5 mg/kg). Twenty-four hours after the final treatment, the mice were killed, 

and smears of the bone marrow cells obtained from the femurs were prepared. The data are shown in 

Table I4. 

The data presented in Table I5 came from peripheral blood smears prepared from mice used in the initial 

range-finding study. These data were used to confirm the bone marrow micronucleus test results without 

the use of additional animals. For this analysis, the mice were killed 48 hours after the third treatment with 

AZT. The suitability of these samples for analysis is based on the well-known kinetics for polychromatic 

erythrocyte (PCE) formation and persistence in mouse bone marrow and peripheral blood (i.e., 

micronucleated PCE frequencies in bone marrow should be similar to frequencies in peripheral blood 

sampled 24 hours later) (MacGregor et al., 1990). Because this was a range-finding study, there was no 

positive control group for this experiment. 
216 AZT and AZT/"-Interferon A/D, NTP TR 469 

Air-dried smears from both tissue types were fixed and stained with acridine orange; 2,000 PCEs per tissue 

per mouse were scored for frequency of micronucleated cells in each of 4 or 5 animals per dose group. 

The results were tabulated as the mean of the pooled results from all animals within a treatment group plus 

or minus the standard error of the mean. The frequency of micronucleated cells among PCEs was analyzed 

by a statistical software package that tested for increasing trend over dose groups with a one-tailed CochranArmitage trend test, followed by pairwise comparisons between each dosed group and the control group 

(Margolin et al., 1990). In the presence of excess binomial variation, as detected by a binomial dispersion 

test, the binomial variance of the Cochran-Armitage test was adjusted upward in proportion to the excess 

variation. In the micronucleus test, an individual trial is considered positive if the trend test P value is less 

than or equal to 0.025 or if the P value for any single dose group is less than or equal to 0.025 divided by 

the number of dose groups. A final call of positive for micronucleus induction is preferably based on 

reproducibly positive trials (as noted above). Ultimately, the final call is determined by the scientific staff 

after considering the results of statistical analyses, the reproducibility of any effects observed, and the 

magnitude of those effects. 

MOUSE PERIPHERAL BLOOD MICRONUCLEUS TEST PROTOCOL 

A detailed discussion of this assay is presented in MacGregor et al. (1990). At the end of the 14-week 

toxicity study, peripheral blood samples were obtained from male and female mice, and smears were 

immediately prepared and fixed in absolute methanol. The methanol-fixed slides were stained with acridine 

orange and coded. Slides were scanned to determine the frequency of micronuclei in 1,000 PCEs and 

1,000 NCEs in each of nine or ten animals per dose group. Data analysis was performed as described 

previously for the short-term in vivo micronucleus tests. 

RESULTS 

AZT is mutagenic. Positive results were obtained with AZT (0.003 to 3 μg/plate) in S. typhimurium strain 

TA102 without S9 activation enzymes and with 30% hamster liver S9; no mutagenic response was detected 

in strain TA97, TA98, TA100, TA104, or TA1535 (0.001 to 6 μg/plate), with or without hamster or rat 

liver S9 (Table I1). In cytogenetic tests with cultured CHO cells, AZT induced SCEs (Table I2), but not 

Abs (Table I3), with and without S9. The SCE response in the absence of S9 was much stronger and 

occurred at much lower doses than the response observed in the presence of S9. AZT, administered by 

gavage three times at 24-hour intervals at doses ranging from 200 to 2,000 mg/kg, induced increased 

frequencies of micronucleated PCEs in bone marrow (Table I4) and peripheral blood (Table I5) samples of 

male mice (Phillips et al., 1991). The increased frequencies of micronuclei were very impressive, with the 

three treatment groups in the bone marrow analysis showing increases that were from three to nine times the 

level induced by the positive control, dimethylbenzanthracene (Table I4). The increases noted in peripheral 

blood (Table I5) were of similar or greater magnitude. Results of a 14-week peripheral blood micronucleus 

test with male mice showed significant increases in the frequencies of micronucleated PCEs and NCEs at 

doses of 100 and 1,000 mg AZT/kg body weight per day (Table I6). No increased frequency of 

micronucleated cells was noted at the lowest dose of 25 mg/kg per day. 
AZT and AZT/"-Interferon A/D, NTP TR 469 217 

TABLE I1 

Mutagenicity of AZT in Salmonella typhimuriuma 

Revertants/plateb 

Strain Dose !S9 

(μg/plate) Trial 1 Trial 2 Trial 3 

TA102 0 

0.003 

0.01

0.03 

0.1 

0.3

0.6 

1 

3 

191 ± 6.3 

190 ± 8.7 

187 ± 9.3 

226 ± 2.5 

334 ± 15.4 

418 ± 9.5 

117 ± 6.9 

145 ± 8.3 

168 ± 10.4 

190 ± 6.3 

200 ± 5.5 

212 ± 6.4 

207 ± 18.8 

183 ± 20.0 

193 ± 3.9 

229 ± 11.2 

300 ± 13.2 

337 ± 15.1 

319 ± 20.7 

333 ± 19.2 

34 ± 3.7c 

Trial summary 

Positive controld 

Positive 

672 ± 72.5 

Positive 

541 ± 8.0 

Positive 

675 ± 22.0 

+30% hamster S9 +30% rat S9 

Trial 1 Trial 2 Trial 3 Trial 1 Trial 2 

TA102 0 

(continued) 0.003 

0.01 

0.03 

0.1 

0.3 

0.6 

1 

3 

328 ± 20.3 

357 ± 10.7 

310 ± 16.8 

357 ± 31.1 

449 ± 9.2 

482 ± 11.0 

282 ± 5.8 

306 ± 7.0 

305 ± 9.6 

325 ± 3.5 

374 ± 22.0 

389 ± 20.6 

456 ± 7.4 

262 ± 1.5 

285 ± 7.1 

277 ± 3.0 

333 ± 8.0 

360 ± 7.4 

356 ± 6.3 

417 ± 14.6 

228 ± 19.9 

355 ± 15.2 

391 ± 4.1 

391 ± 12.5 

376 ± 14.7 

394 ± 10.7 

368 ± 25.7 

238 ± 17.0 

288 ± 7.5 

289 ± 6.6 

285 ± 12.0 

295 ± 22.0 

293 ± 6.6 

250 ± 7.2 

104 ± 14.4c 

Trial summary 

Positive control 

Positive 

501 ± 13.4 

Positive 

450 ± 10.9 

Weakly Positive 

636 ± 117.1 

Negative 

443 ± 0.3 

Negative 

554 ± 31.7 

!S9 +30% hamster S9 +30% rat S9 

TA104 0 

0.003 

0.01 

0.03 

0.1 

0.3 

1 

307 ± 12.4 

326 ± 11.2 

326 ± 5.0 

344 ± 6.1 

347 ± 2.9 

277 ± 14.6 

343 ± 11.7 

382 ± 12.1 

385 ± 22.4 

410 ± 15.4 

359 ± 10.7 

289 ± 23.2 

347 ± 5.8 

376 ± 11.0 

404 ± 6.9 

390 ± 4.2 

372 ± 1.7 

324 ± 26.5 

Trial summary Negative 

Positive control 

Equivocal 

485 ± 2.9 

Equivocal 

852 ± 18.6 833 ± 18.5 
218 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE I1 

Mutagenicity of AZT in Salmonella typhimurium 

Revertants/plate 

Strain Dose !S9 +30% hamster S9 +30% rat S9 

(μg/plate) Trial 1 Trial 2 Trial 1 Trial 2 

TA100 0 132 ± 5.2 128 ± 4.0 114 ± 6.4 158 ± 7.5 136 ± 5.1 

0.01 116 ± 5.5 132 ± 3.8 

0.03 128 ± 7.3 118 ± 4.7 137 ± 11.9 

0.1 121 ± 5.2 140 ± 8.0 111 ± 8.4 155 ± 11.0 135 ± 10.0 

0.3 107 ± 7.5 145 ± 2.8 111 ± 7.4 152 ± 9.4 137 ± 3.0 

1 81 ± 2.6 118 ± 12.3 122 ± 3.5 122 ± 2.9 120 ± 4.2 

3 6 ± 1.9c 25 ± 2.4 27 ± 1.7 

6 1 ± 1.0 6 ± 2.1c 

Trial summary Negative Negative Negative Negative Negative 

Positive control 465 ± 17.2 437 ± 41.9 453 ± 28.8 408 ± 13.7 427 ± 37.8 

!S9 +30% hamster S9 +30% rat S9 

TA1535 0 10 ± 1.2 10 ± 1.2 13 ± 1.5 

0.003 11 ± 1.2 

0.01 10 ± 2.3 9 ± 0.9 17 ± 0.6 

0.03 8 ± 1.2 11 ± 4.3 12 ± 3.2 

0.1 9 ± 0.3 12 ± 1.5 13 ± 3.0 

0.3 9 ± 2.1 11 ± 0.9 13 ± 1.5 

1 10 ± 1.7 12 ± 1.2 

Trial summary Negative Negative Negative 

Positive control 454 ± 20.7 255 ± 2.1 102 ± 6.2 

!S9 +30% hamster S9 +30% rat S9 

TA97 0 177 ± 12.9 146 ± 9.2 194 ± 5.4 

0.003 204 ± 3.8 

0.01 213 ± 2.4 144 ± 3.0 204 ± 14.9 

0.03 201 ± 7.0 143 ± 5.8 196 ± 7.8 

0.1 166 ± 15.2 143 ± 12.8 174 ± 1.2 

0.3 155 ± 2.1 130 ± 2.3 147 ± 13.6 

1 134 ± 7.5 170 ± 3.0 

Trial summary Negative Negative Negative 

Positive control 381 ± 15.2 499 ± 39.3 410 ± 19.7 
219 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE I1 

Mutagenicity of AZT in Salmonella typhimurium 

Revertants/plate Strain Dose 

(μg/plate) !S9 +30% hamster S9 +30% rat S9 

TA98 0 19 ± 1.8	 26 ± 4.8 24 ± 2.3 

0.001 16 ± 1.0	 22 ± 1.9 

0.003 20 ± 2.6	 22 ± 3.4 21 ± 4.0 

0.01 22 ± 0.9	 22 ± 2.2 18 ± 1.7 

0.03 26 ± 4.0	 19 ± 2.3 25 ± 2.8 

0.1 22 ± 3.2	 16 ± 2.8 17 ± 1.7 

0.3	 17 ± 2.6 

Trial summary Negative Negative Negative 

Positive control 416 ± 12.3 306 ± 6.4 92 ± 0.9 

a Study was performed at SRI International. The detailed protocol is presented in Zeiger et al. (1992). 0 μg/plate was the solvent control. b Revertants are presented as mean ± standard error from three plates. 

Slight toxicity d	 The positive controls in the absence of metabolic activation were sodium azide (TA100 and TA1535), 9-aminoacridine (TA97), 

4-nitro-o-phenylenediamine (TA98), mytomycin-C (TA102), and methyl methanesulfonate (TA104). The positive control for metabolic 

activation with all strains was 2-aminoanthracene. 
220 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE I2 

Induction of Sister Chromatid Exchanges in Chinese Hamster Ovary Cells by AZTa 

Total No. of SCEs/ Relative 

Dose Cells Chromo- No. of Chromo- SCEs/ Hrs Change of SCEs/ 

Compound (μg/mL) Scored somes SCEs some Cell in BrdU Chromosomeb 

(%) 

!S9 

Trial 1 

Summary: Positive 

c Dimethylsulfoxide	 50 1,048 385 0.36 7.7 26.0 

Mitomycin-Cd 0.001 50 1,047 687 0.65 13.7 26.0 78.61 

0.004 10 208 187 0.89 18.7 26.0 144.73 

AZT 8.3 50 1,049 715 0.68 14.3 26.0 85.54* 

25 50 1,049 918 0.87 18.4 26.0 138.22* 

83 25 525 538 1.02 21.5 26.0 178.95* 

250 0 31.0e 

P<0.001f 

Trial 2 

Summary: Positive 

Dimethylsulfoxide	 50 1,049 384 0.36 7.7 26.0 

Mitomycin-C 0.001 50 1,051 532 0.50 10.6 26.0 38.28 

AZT 8.3 50 1,049 564 0.53 11.3 26.0 46.87* 

25 50 1,047 645 0.61 12.9 26.0 68.29* 

83 25 522 481 0.92 19.2 26.0 151.72* 

250 0 31.0e 

P<0.001 

+S9 

Summary: Positive 

Dimethylsulfoxide	 50 1,042 380 0.36 7.6 26.0 

Cyclophosphamided 0.125 50 1,049 670 0.63 13.4 26.0 75.14 

0.5 10 210 204 0.97 20.4 26.0 166.38 

AZT 250 50 1,050 443 0.42 8.9 26.0 15.69 

833 50 1,049 479 0.45 9.6 26.0 25.21* 

2,500 50 1,047 551 0.52 11.0 26.0 44.31* 

P<0.001 

*	 Positive response (P#0.01) versus the solvent control a Study was performed at SITEK Research Laboratories. A detailed description of the protocol is presented in Galloway et al. (1987). 

SCE=sister chromatid exchange; BrdU=bromodeoxyuridine b	 SCEs/chromosome in treated cells versus SCEs/chromosome in solvent control cells 

Solvent control 

d Positive control e Because AZT induced a delay in the cell division cycle, the harvest time was extended to maximize the number of second-division metaphase 

cells available for analysis. f	 Significance of SCEs/chromosome tested by the linear regression trend test versus log of the dose 

c 
221 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE I3 

Induction of Chromosomal Aberrations in Chinese Hamster Ovary Cells by AZTa 

!S9 +S9 

Dose Total Cells No. of Abs/ Cells with Dose Total Cells No. of Abs/ Cells with 

(μg/mL) Scored Abs Cell Abs (%) (μg/mL) Scored Abs Cell Abs (%) 

Harvest time: 14.5 hours 

Summary: Negative 

Harvest time: 12.0 hours 

Summary: Negative 

Dimethylsulfoxideb 

200 3 0.02 1.5 

Dimethylsulfoxide 

200 6 0.03 3.0 

Mitomycin-Cc 

0.4 25 22 0.88 52 

Cyclophosphamidec 

20 25 31 1.24 48 

AZT 

541 

1,163 

2,500 

200 

200 

200 

3 

4 

1 

0.02 

0.02 

0.01 

1.5 

2.0 

0.5 

AZT 

541 

1,163 

2,500 

200 

200 

200 

3 

3 

4 

0.02 

0.02 

0.02 

1.5 

1.5 

2.0 

P=0.803d P=0.751 

a Study was performed at SITEK Research Laboratories. The detailed protocol is presented in Galloway et al. (1987). Abs=aberrations b Solvent control 

Positive control 

d Significance of percent cells with aberrations tested by the linear regression trend test versus log of the dose 

TABLE I4 

Frequency of Micronuclei in Bone Marrow Polychromatic Erythrocytes of Male Mice Treated with AZT 

by Gavage for 3 Daysa 

Compound Dose Number of Mice Micronucleated PCEs/1,000 PCEsb 

(mg/kg/day) with Erythrocytes Scored 

Corn oilc 

0 5 2.1 ± 0.71 

Dimethylbenzanthracened 

12.5 5 4.0 ± 0.76 

AZT 

500 5 15.1 ± 3.13* 

1,000 5 13.0 ± 2.20* 

2,000 5 35.4 ± 3.34* 

P<0.001e 

* Significantly different from the solvent control (P#0.001) a Study was performed at Integrated Laboratory Systems. The detailed protocol and these data are presented in Phillips et al. (1991). 

PCE=polychromatic erythrocyte b Mean ± standard error
 

Solvent control
 d Positive control e Significance of micronucleated PCEs/1,000 PCEs tested by the one-tailed trend test; significant at P#0.025 (Margolin et al., 1990) 

c 
222 

c 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE I5 

Frequency of Micronuclei in Peripheral Blood Erythrocytes of Male Mice Treated with AZT by Gavage 

for 3 Daysa 

Compound Dose 

(mg/kg/day) 

Number of Mice 

with Erythrocytes Scored 

Micronucleated PCEs/1,000 PCEsb 

Corn oilc 0 5 2.6 ± 0.19 

AZT 200 

1,000 

2,000 

5 

4 

5 

15.2 ± 1.10* 

18.1 ± 2.75* 

53.4 ± 12.75* 

P<0.001d 

* Significantly different from the solvent control (P#0.001) a Study was performed at Integrated Laboratory Systems. The protocol and these data are presented in Phillips et al. (1991). 

PCE=polychromatic erythrocyte b Mean ± standard error 

Solvent control 

d Significance of micronucleated PCEs/1,000 PCEs tested by the one-tailed trend test; significant at P#0.025 (Margolin et al., 1990) 

TABLE I6 

Frequency of Micronuclei in Peripheral Blood Erythrocytes of Male Mice Treated with AZT by Gavage 

for 14 Weeksa 

Compound Dose Number of Mice Micronucleated Cells/1,000 Cellsb 

(mg/kg/day) with Erythrocytes Scored PCEs NCEs 

Corn oilc 0 10 2.1 ± 0.31 2.5 ± 0.27 

AZT 25 9 2.7 ± 0.41 2.8 ± 0.32 

100 9 12.9 ± 1.57* 5.9 ± 0.48* 

1,000 9 57.6 ± 4.03* 55.3 ± 2.67* 

d P<0.001 P<0.001 

* Significantly different from the solvent control (P#0.001) a Study was performed at Integrated Laboratory Systems. The detailed protocol and these data are presented in Phillips et al. (1991). 

PCE=polychromatic erythrocyte; NCE=normochromatic erythrocyte b Mean ± standard error 

Solvent control 

d Significance of micronucleated cells/1,000 cells tested by the one-tailed trend test; significant at P#0.025 (Margolin et al., 1990) 
223 

APPENDIX J
 

ORGAN WEIGHTS AND 

ORGAN-WEIGHT-TO-BODY-WEIGHT RATIOS
 

TABLE J1	 Organ Weights and Organ-Weight-to-Body-Weight Ratios for Mice 

in the 14-Week Gavage Study of AZT ................................... 224 
224 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE J1 

Organ Weights and Organ-Weight-to-Body-Weight Ratios for Mice in the 14-Week Gavage Study of AZTa 

Vehicle Control 50 mg/kg 100 mg/kg 200 mg/kg 800 mg/kg 2,000 mg/kg 

Male 

Core Study 

n 10 10 10 10 10 10 

Necropsy body wt 32.4 ± 0.6 34.0 ± 0.7 35.1 ± 1.1 34.6 ± 0.9 33.8 ± 0.7 32.0 ± 0.6 

Heart 

Absolute 0.138 ± 0.004 0.158 ± 0.004** 0.147 ± 0.004 0.152 ± 0.004 0.142 ± 0.002 0.137 ± 0.004 

Relative 4.26 ± 0.09 4.68 ± 0.21 4.20 ± 0.09 4.42 ± 0.16 4.21 ± 0.07 4.29 ± 0.13 

L. Kidney 

Absolute 0.282 ± 0.008 0.295 ± 0.011 0.289 ± 0.009 0.324 ± 0.008** 0.281 ± 0.005 0.276 ± 0.006 

Relative 8.71 ± 0.22 8.71 ± 0.36 8.28 ± 0.31 9.42 ± 0.30 8.34 ± 0.19 8.64 ± 0.20 

R. Kidney 

Absolute 0.283 ± 0.007 0.306 ± 0.007 0.307 ± 0.008 0.327 ± 0.007** 0.292 ± 0.009 0.282 ± 0.007 

Relative 8.75 ± 0.23 9.02 ± 0.20 8.78 ± 0.23 9.49 ± 0.23 8.64 ± 0.24 8.82 ± 0.23 

Liver 

Absolute 1.287 ± 0.039 1.572 ± 0.048** 1.344 ± 0.054 1.607 ± 0.034** 1.338 ± 0.063 1.297 ± 0.031 

Relative 39.74 ± 0.95 46.26 ± 1.09** 38.31 ± 1.22 46.61 ± 0.75** 39.46 ± 1.21 40.60 ± 1.16 

Lung 

Absolute 0.175 ± 0.006 0.182 ± 0.006b 0.182 ± 0.005 0.176 ± 0.004 0.178 ± 0.009 0.172 ± 0.003 

Relative 5.42 ± 0.22 5.39 ± 0.19b 5.19 ± 0.10 5.12 ± 0.17 5.27 ± 0.24 5.39 ± 0.16 

R. Testis 

Absolute 0.114 ± 0.003 0.115 ± 0.003 0.121 ± 0.003 0.116 ± 0.002 0.119 ± 0.002 0.104 ± 0.002* 

Relative 3.52 ± 0.11 3.38 ± 0.08 3.47 ± 0.10 3.38 ± 0.09 3.53 ± 0.07 3.25 ± 0.10 

Thymus 

Absolute 0.031 ± 0.002 0.042 ± 0.002**b 0.038 ± 0.003 0.034 ± 0.002 0.035 ± 0.002 0.030 ± 0.001 

Relative 0.97 ± 0.05 1.24 ± 0.06*b 1.09 ± 0.08 0.99 ± 0.05 1.03 ± 0.07 0.93 ± 0.05 

Recovery Study 

n 10 — 10 — 10 10 

Necropsy body wt 37.1 ± 1.0 39.7 ± 0.6 40.0 ± 1.2 37.1 ± 0.9 

Heart 

Absolute 0.152 ± 0.004 0.159 ± 0.003 0.165 ± 0.005* 0.151 ± 0.003 

Relative 4.12 ± 0.11 4.01 ± 0.09 4.14 ± 0.13 4.08 ± 0.07 

L. Kidney 

Absolute 0.315 ± 0.006 0.318 ± 0.004 0.319 ± 0.008 0.305 ± 0.007 

Relative 8.53 ± 0.20 8.03 ± 0.17 8.00 ± 0.19 8.25 ± 0.21 

R. Kidney 

Absolute 0.328 ± 0.011 0.333 ± 0.004 0.347 ± 0.010 0.326 ± 0.009 

Relative 8.88 ± 0.29 8.40 ± 0.14 8.69 ± 0.19 8.80 ± 0.22 

Liver 

Absolute 1.675 ± 0.051 1.754 ± 0.029 1.763 ± 0.054 1.721 ± 0.061 

Relative 45.23 ± 0.96 44.25 ± 0.98 44.21 ± 1.28 46.30 ± 0.79 

Lung 

Absolute 0.183 ± 0.005 0.187 ± 0.003 0.193 ± 0.006 0.178 ± 0.005 

Relative 4.96 ± 0.15 4.72 ± 0.09 4.85 ± 0.17 4.84 ± 0.25 

R. Testis 

Absolute 0.122 ± 0.002 0.122 ± 0.003 0.121 ± 0.003 0.116 ± 0.002 

Relative 3.30 ± 0.10 3.06 ± 0.08 3.03 ± 0.10 3.13 ± 0.10 

Thymus 

Absolute 0.033 ± 0.002 0.034 ± 0.002 0.038 ± 0.002 0.038 ± 0.002 

Relative 0.89 ± 0.06 0.86 ± 0.05 0.94 ± 0.05 1.04 ± 0.05 
AZT and AZT/"-Interferon A/D, NTP TR 469 225 

TABLE J1 

Organ Weights and Organ-Weight-to-Body-Weight Ratios for Mice in the 14-Week Gavage Study of AZT 

Vehicle Control 50 mg/kg 100 mg/kg 200 mg/kg 800 mg/kg 2,000 mg/kg 

Female 

Core Study 

n 10 10 9 8 10 9 

Necropsy body wt 28.8 ± 1.2 29.1 ± 0.6 27.4 ± 0.5 26.8 ± 0.7 27.3 ± 0.6 26.8 ± 1.1 

Heart 

Absolute 0.115 ± 0.003 0.120 ± 0.003 0.116 ± 0.003 0.121 ± 0.006 0.113 ± 0.003 0.113 ± 0.004 

Relative 4.04 ± 0.18 4.14 ± 0.13 4.22 ± 0.10 4.55 ± 0.26 4.15 ± 0.11 4.28 ± 0.19 

L. Kidney 

Absolute 0.186 ± 0.006 0.180 ± 0.005 0.182 ± 0.004 0.179 ± 0.003 0.176 ± 0.003 0.186 ± 0.003 

Relative 6.51 ± 0.23 6.19 ± 0.14 6.64 ± 0.10 6.70 ± 0.10 6.46 ± 0.10 7.01 ± 0.28 

R. Kidney 

Absolute 0.192 ± 0.005 0.188 ± 0.004 0.193 ± 0.006 0.191 ± 0.005 0.190 ± 0.004 0.196 ± 0.005 

Relative 6.71 ± 0.16 6.47 ± 0.10 7.05 ± 0.14 7.16 ± 0.18 6.97 ± 0.07 7.35 ± 0.19** 

Liver 

Absolute 1.285 ± 0.045 1.322 ± 0.038 1.262 ± 0.050 1.244 ± 0.040 1.279 ± 0.030 1.274 ± 0.054 

Relative 44.85 ± 1.06 45.58 ± 1.39 45.94 ± 1.41 46.56 ± 1.26 46.91 ± 0.59 47.72 ± 1.26 

Lung 

Absolute 0.171 ± 0.007 0.178 ± 0.009 0.172 ± 0.008 0.179 ± 0.013 0.180 ± 0.019 0.174 ± 0.007 

Relative 5.99 ± 0.27 6.15 ± 0.35 6.26 ± 0.24 6.72 ± 0.53 6.54 ± 0.58 6.59 ± 0.35 

Thymus 

Absolute 0.049 ± 0.003 0.056 ± 0.003 0.047 ± 0.002 0.050 ± 0.002 0.044 ± 0.002 0.040 ± 0.002** 

Relative 1.72 ± 0.09 1.93 ± 0.10 1.71 ± 0.07 1.86 ± 0.06 1.59 ± 0.06 1.50 ± 0.07 

Recovery Study 

n 10 — 10 — 10 9 

Necropsy body wt 30.8 ± 1.5 32.2 ± 0.7 33.3 ± 1.1 29.8 ± 1.1 

Heart 

Absolute 0.119 ± 0.005 0.127 ± 0.005 0.123 ± 0.004 0.128 ± 0.004 

Relative 3.93 ± 0.24 3.94 ± 0.13 3.71 ± 0.12 4.35 ± 0.26 

L. Kidney 

Absolute 0.196 ± 0.005 0.205 ± 0.007 0.205 ± 0.009 0.213 ± 0.010 

Relative 6.43 ± 0.23 6.36 ± 0.15 6.19 ± 0.27 7.26 ± 0.48 

R. Kidney 

Absolute 0.203 ± 0.006 0.213 ± 0.006 0.218 ± 0.008 0.230 ± 0.011 

Relative 6.66 ± 0.23 6.60 ± 0.11 6.60 ± 0.27 7.82 ± 0.50* 

Liver 

Absolute 1.319 ± 0.048 1.399 ± 0.040 1.460 ± 0.047b 1.419 ± 0.059 

Relative 43.08 ± 1.24 43.41 ± 0.79 44.16 ± 0.92b 47.64 ± 1.14** 

Lung 

Absolute 0.175 ± 0.009 0.184 ± 0.008 0.172 ± 0.004 0.190 ± 0.016 

Relative 5.76 ± 0.37 5.72 ± 0.23 5.21 ± 0.17 6.39 ± 0.45 

Thymus 

Absolute 0.050 ± 0.003 0.048 ± 0.005 0.044 ± 0.003 0.050 ± 0.003 

Relative 1.63 ± 0.11 1.50 ± 0.14 1.34 ± 0.09 1.69 ± 0.11 

* Significantly different (P#0.05) from the control group by Williams’ or Dunnett’s test 

** P#0.01 a Organ weights and body weights are given in grams; organ-weight-to-body-weight ratios (relative weights) are given as mg organ weight/g body weight 

(mean ± standard error). The recovery study only included animals in the vehicle control, 100, 800, and 2,000 mg/kg groups. b n=9 
226 AZT and AZT/"-Interferon A/D, NTP TR 469 
227 

APPENDIX K 

HEMATOLOGY AND 

BONE MARROW ANALYSES 

TABLE K1 

TABLE K2 

TABLE K3 

TABLE K4 

TABLE K5 

Hematology and Bone Marrow Data for Mice in the 14-Week Gavage Study 

of AZT ........................................................ 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study 

of AZT ........................................................ 

Hematology and Bone Marrow Data for Mice in the 2-Year Subcutaneous Study 

of "-Interferon A/D ............................................... 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study 

of AZT/500 U "-Interferon A/D ....................................... 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study 

of AZT/5,000 U "-Interferon A/D ...................................... 

228 

236 

250 

264 

278 
228 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K1 

Hematology and Bone Marrow Data for Mice in the 14-Week Gavage Study of AZTa 

Vehicle Control 50 mg/kg 100 mg/kg 200 mg/kg 800 mg/kg 2,000 mg/kg 

Male 

Hematology 

Core Study 

n 

Day 5 9 10 10 9 10 10 

Day 23 10 9 10 8 10 9 

Week 14 10 10 10 10 10 10 

Hematocrit (%) 

Day 5 45.2 ± 0.7 44.3 ± 0.3 43.7 ± 0.5 43.8 ± 0.3 43.8 ± 0.6 43.0 ± 0.6* 

Day 23 48.2 ± 0.6 48.2 ± 0.6 47.1 ± 0.4 45.0 ± 1.1** 43.5 ± 0.4** 41.5 ± 0.5** 

Week 14 50.6 ± 0.8 49.5 ± 0.5 49.7 ± 0.5 50.6 ± 0.8 47.7 ± 0.6** 44.9 ± 0.3** 

Hemoglobin (g/dL) 

Day 5 

Day 23 

15.4 ± 0.3 

15.8 ± 0.2 

15.2 ± 0.1 

15.9 ± 0.1 

15.0 ± 0.2 

15.4 ± 0.1 

15.0 ± 0.1 

15.0 ± 0.1**b 

15.0 ± 0.2 

14.3 ± 0.1** 

14.7 ± 0.2 

13.8 ± 0.2** 

Week 14 16.2 ± 0.1 16.0 ± 0.1 16.1 ± 0.1 16.0 ± 0.1 15.1 ± 0.1** 14.1 ± 0.1** 

Erythrocytes (10 /μL) 6 

Day 5 9.48 ± 0.14 9.26 ± 0.06 9.19 ± 0.11 9.18 ± 0.05 9.17 ± 0.13 8.96 ± 0.12** 

Day 23 9.75 ± 0.11 9.55 ± 0.12 9.16 ± 0.08** 8.70 ± 0.20** 8.09 ± 0.07** 7.62 ± 0.12** 

Week 14 10.12 ± 0.16 9.48 ± 0.09** 9.29 ± 0.08** 8.98 ± 0.11** 7.85 ± 0.08** 6.71 ± 0.06** 

Reticulocytes (10 /μL) 6 

Day 5 0.23 ± 0.02 0.17 ± 0.02 0.17 ± 0.02 0.14 ± 0.02* 0.07 ± 0.01** 0.04 ± 0.01** 

Day 23 0.14 ± 0.02 0.14 ± 0.01 0.16 ± 0.02 0.12 ± 0.01 0.14 ± 0.01 0.11 ± 0.01 

Week 14 0.35 ± 0.04 0.38 ± 0.03 0.29 ± 0.03 0.40 ± 0.03c 0.21 ± 0.02*c 0.21 ± 0.02** 

Nucleated erythrocytes (10 /μL) 3 

Day 5 0.02 ± 0.02 0.01 ± 0.01 0.00 ± 0.00 0.01 ± 0.01 0.01 ± 0.01 0.02 ± 0.01 

Day 23 0.01 ± 0.01 0.00 ± 0.00 0.00 ± 0.00 0.01 ± 0.01 0.01 ± 0.01 0.00 ± 0.00 

Week 14 0.00 ± 0.00c 0.00 ± 0.00c 0.00 ± 0.00c 0.03 ± 0.03 0.00 ± 0.00 0.00 ± 0.00 

Mean cell volume (fL) 

Day 5 47.8 ± 0.2 47.8 ± 0.2 47.6 ± 0.3 47.7 ± 0.2 47.7 ± 0.2 48.0 ± 0.3 

Day 23 49.4 ± 0.3 50.6 ± 0.2** 51.4 ± 0.2** 51.8 ± 0.3** 54.1 ± 0.3** 54.6 ± 0.3** 

Week 14 50.0 ± 0.3 52.2 ± 0.2** 53.6 ± 0.4** 56.5 ± 0.4** 60.9 ± 0.4** 67.1 ± 0.4** 

Mean cell hemoglobin (pg) 

Day 5 

Day 23 

16.3 ± 0.1 

16.2 ± 0.1 

16.4 ± 0.1 

16.6 ± 0.1** 

16.4 ± 0.1 

16.8 ± 0.0** 

16.3 ± 0.1 

16.9 ± 0.2**b 

16.3 ± 0.1 

17.8 ± 0.1** 

16.4 ± 0.1 

18.1 ± 0.1** 

Week 14 16.1 ± 0.2 16.9 ± 0.2** 17.3 ± 0.2** 17.8 ± 0.1** 19.3 ± 0.1** 21.0 ± 0.1** 

Mean cell hemoglobin concentration (g/dL) 

Day 5 

Day 23 

34.1 ± 0.2 

32.7 ± 0.2 

34.3 ± 0.1 

33.0 ± 0.2 

34.4 ± 0.1 

32.8 ± 0.2 

34.3 ± 0.2 

32.6 ± 0.3b 

34.3 ± 0.2 

32.9 ± 0.2 

34.2 ± 0.1 

33.2 ± 0.1 

Week 14 32.1 ± 0.4 32.4 ± 0.3 32.4 ± 0.4 31.7 ± 0.3 31.7 ± 0.3 31.4 ± 0.2 

Platelets (10 /μL) 3 

Day 5 1,111.0 ± 53.8 1,033.8 ± 43.7 1,137.8 ± 36.7 1,043.0 ± 54.5 1,014.8 ± 33.8 1,103.3 ± 28.7 

Day 23 878.5 ± 45.0 828.3 ± 43.8 919.3 ± 42.1 1,010.8 ± 45.9 1,052.1 ± 43.3* 1,302.3 ± 44.3** 

Week 14 

Leukocytes (10 /μL) 3 1,111.1 ± 25.5 1,183.0 ± 35.6 1,231.6 ± 40.7* 1,160.0 ± 57.8 1,206.6 ± 43.8 1,297.6 ± 37.5** 

Day 5 6.23 ± 0.21 6.41 ± 0.21 6.08 ± 0.14 6.09 ± 0.28 6.40 ± 0.19 5.91 ± 0.31 

Day 23 7.45 ± 0.44 6.39 ± 0.30 7.04 ± 0.36 6.93 ± 0.34 6.34 ± 0.29 6.26 ± 0.22 

Week 14 2.57 ± 0.37 3.09 ± 0.46 4.62 ± 0.67 4.80 ± 0.88 3.82 ± 0.56 2.78 ± 0.41 

Segmented neutrophils (10 /μL) 3 

Day 5 0.73 ± 0.09 0.73 ± 0.06 0.90 ± 0.08 0.78 ± 0.14 0.70 ± 0.09 0.56 ± 0.08 

Day 23 0.94 ± 0.16 0.90 ± 0.12 0.77 ± 0.13 0.70 ± 0.07 0.49 ± 0.05 0.68 ± 0.11 

Week 14 0.66 ± 0.08c 0.88 ± 0.17c 0.74 ± 0.11c 0.99 ± 0.12 0.89 ± 0.12 0.70 ± 0.12 

Lymphocytes (10 /μL) 3 

Day 5 5.21 ± 0.19 5.56 ± 0.17 5.02 ± 0.18 5.19 ± 0.24 5.55 ± 0.20 5.19 ± 0.30 

Day 23 6.38 ± 0.32 5.41 ± 0.34 6.12 ± 0.28 6.08 ± 0.34 5.70 ± 0.30 5.42 ± 0.21 

Week 14 1.73 ± 0.33c 2.09 ± 0.42c 3.43 ± 0.60c 3.58 ± 0.82 2.80 ± 0.49 1.97 ± 0.28 
AZT and AZT/"-Interferon A/D, NTP TR 469 229 

TABLE K1 

Hematology and Bone Marrow Data for Mice in the 14-Week Gavage Study of AZT 

Vehicle Control 50 mg/kg 100 mg/kg 200 mg/kg 800 mg/kg 2,000 mg/kg 

Male (continued) 

Hematology (continued) 

Core Study (continued) 

n 

Day 5 9 10 10 9 10 10 

Day 23 10 9 10 8 10 9 

Week 14 10 10 10 10 10 10 

Atypical lymphocytes (10 /μL) 3 

Day 5 0.00 ± 0.00 0.02 ± 0.01 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Day 23 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 14 0.00 ± 0.00c 0.00 ± 0.00c 0.00 ± 0.00c 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Monocytes (10 /μL) 3 

Day 5 0.08 ± 0.02 0.05 ± 0.02 0.05 ± 0.02 0.06 ± 0.02 0.04 ± 0.02 0.05 ± 0.02 

Day 23 0.04 ± 0.03 0.01 ± 0.01 0.01 ± 0.01 0.00 ± 0.00 0.04 ± 0.02 0.03 ± 0.02 

Week 14 0.03 ± 0.02c 0.01 ± 0.01c 0.03 ± 0.02c 0.02 ± 0.01 0.01 ± 0.01 0.01 ± 0.01 

Eosinophils (10 /μL) 3 

Day 5 0.21 ± 0.03 0.10 ± 0.03 0.11 ± 0.04 0.07 ± 0.02* 0.12 ± 0.02 0.13 ± 0.04 

Day 23 0.10 ± 0.03 0.09 ± 0.02 0.13 ± 0.03 0.11 ± 0.02 0.12 ± 0.03 0.16 ± 0.04 

Week 14 0.04 ± 0.02c 0.12 ± 0.04c 0.13 ± 0.04c 0.19 ± 0.05 0.11 ± 0.03 0.12 ± 0.03 

Recovery Study 

n 10 — 10 — 10 10 

Hematocrit (%) 

Week 14 48.0 ± 0.3 47.9 ± 0.5 45.9 ± 0.3** 43.4 ± 0.7** 

Week 17 50.2 ± 0.6 48.6 ± 0.4 49.3 ± 0.4 48.5 ± 0.5 

Hemoglobin (g/dL) 

Week 14 15.9 ± 0.1 15.6 ± 0.1 14.4 ± 0.1** 13.4 ± 0.2** 

Week 17 16.8 ± 0.1 16.5 ± 0.1* 16.5 ± 0.1* 16.2 ± 0.2** 

Erythrocytes (10 /μL) 6 

Week 14 9.61 ± 0.07 8.92 ± 0.11** 7.51 ± 0.08** 6.45 ± 0.13** 

Week 17 10.27 ± 0.11 9.75 ± 0.06** 9.59 ± 0.08** 9.43 ± 0.13** 

Reticulocytes (10 /μL) 6 

Week 14 0.08 ± 0.01 0.08 ± 0.01 0.07 ± 0.02 0.05 ± 0.01 

Week 17 0.11 ± 0.02e 0.09 ± 0.02 0.12 ± 0.02 0.13 ± 0.02 

Nucleated erythrocytes (10 /μL) 3 

Week 14 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 17 0.00 ± 0.00 0.00 ± 0.00c 0.01 ± 0.01 0.01 ± 0.01 

Mean cell volume (fL) 

Week 14 50.1 ± 0.2 53.8 ± 0.2** 61.1 ± 0.4** 67.4 ± 0.5** 

Week 17 49.1 ± 0.3 49.7 ± 0.2* 51.5 ± 0.3** 51.4 ± 0.3** 

Mean cell hemoglobin (pg) 

Week 14 16.6 ± 0.1 17.5 ± 0.1** 19.1 ± 0.1** 20.8 ± 0.2** 

Week 17 16.4 ± 0.1 16.9 ± 0.1** 17.2 ± 0.1** 17.2 ± 0.2** 

Mean cell hemoglobin concentration (g/dL) 

Week 14 33.2 ± 0.2 32.6 ± 0.2 31.3 ± 0.2** 31.0 ± 0.3** 

Week 17 33.6 ± 0.3 33.9 ± 0.2 33.4 ± 0.2 33.4 ± 0.3 

Platelets (10 /μL) 3 

Week 14 1,086.8 ± 48.3 1,173.6 ± 22.8 1,245.6 ± 27.4** 1,554.2 ± 55.8** 

Week 17 

Leukocytes (10 /μL) 3 1,112.0 ± 44.9 1,152.7 ± 19.1 1,172.0 ± 41.1 1,215.6 ± 28.4 

Week 14 8.37 ± 0.57 8.44 ± 0.50 8.35 ± 0.51 7.37 ± 0.25 

Week 17 6.78 ± 0.34 6.07 ± 0.58c 5.92 ± 0.41 5.84 ± 0.44 
230 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K1 

Hematology and Bone Marrow Data for Mice in the 14-Week Gavage Study of AZT 

Vehicle Control 50 mg/kg 100 mg/kg 200 mg/kg 800 mg/kg 2,000 mg/kg 

Male (continued) 

Hematology (continued) 

Recovery Study (continued) 

n 10 — 10 — 10 10 

Segmented neutrophils (10 /μL) 3 

Week 14 

Week 17 

Lymphocytes (10 /μL) 3 

Week 14 

Week 17 

Atypical lymphocytes (10 /μL) 3 

Week 14 

Week 17 

Monocytes (10 /μL) 3 

Week 14 

Week 17 

Eosinophils (10 /μL) 3 

Week 14 

Week 17 

1.36 ± 0.17 

1.05 ± 0.16 

6.79 ± 0.43 

5.50 ± 0.28 

0.00 ± 0.00 

0.00 ± 0.00 

0.07 ± 0.03 

0.05 ± 0.02 

0.16 ± 0.03 

0.17 ± 0.03 

1.71 ± 0.17 

0.89 ± 0.10c 

6.51 ± 0.38 

5.04 ± 0.53c 

0.00 ± 0.00 

0.00 ± 0.00c 

0.03 ± 0.02 

0.04 ± 0.02c 

0.23 ± 0.06 

0.11 ± 0.03c 

1.32 ± 0.20 

0.86 ± 0.05 

6.69 ± 0.36 

4.83 ± 0.36 

0.00 ± 0.00 

0.00 ± 0.00 

0.01 ± 0.01 

0.03 ± 0.02 

0.23 ± 0.05c 

0.18 ± 0.05 

1.03 ± 0.12 

0.84 ± 0.13 

6.05 ± 0.26 

4.83 ± 0.34 

0.00 ± 0.00 

0.00 ± 0.00 

0.06 ± 0.02 

0.06 ± 0.02 

0.22 ± 0.04 

0.10 ± 0.02 

Bone Marrow Analyses 

Core Study 

n 10 — 9 — 9 8 

Total femoral count 

(10 /femur) 6 

M:E ratio 

Rubriblasts (10 )

6 

Prorubricytes (10 )

6 

Rubricytes (10 )

6 

Metarubricytes (10 )

6 

Myeloblasts (10 )

6 

Promyelocytes (10 )

6 

Neutrophilic myelocytes (10 )

6 

Neutrophilic metamyelocytes (10 )

6 

Neutrophilic bands (10 )

6 

Neutrophilic segments (10 )

6 

Eosinophilic metamyelocytes (10 )

6 

Eosinophilic bands (10 )

6 

Eosinophilic myelocytes (10 )

6 

Eosinophilic segments (10 )

6 

Basophilic myelocytes (10 )

6 

Basophilic metamyelocytes (10 )

6 

Basophilic bands (10 )

6 

Basophilic segments (10 )

6 

Bone marrow lymphocytes (10 )

6 

Bone marrow macrophages (10 )

6 

Bone marrow monocytes (10 )

6 

20.17 ± 1.29 

2.34 ± 0.11 

0.38 ± 0.05 

0.63 ± 0.06 

2.30 ± 0.24 

1.42 ± 0.14 

0.42 ± 0.05 

0.77 ± 0.06 

2.05 ± 0.19 

0.73 ± 0.15 

1.84 ± 0.24 

4.73 ± 0.23 

0.06 ± 0.01 

0.10 ± 0.02 

0.072 ± 0.027 

0.048 ± 0.013 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

3.70 ± 0.29 

0.043 ± 0.011 

0.000 ± 0.000 

19.84 ± 0.84 

2.05 ± 0.11d 

0.51 ± 0.06 

0.64 ± 0.08 

2.54 ± 0.18 

1.30 ± 0.06 

0.31 ± 0.04 

0.66 ± 0.04 

1.88 ± 0.27 

0.67 ± 0.11 

1.58 ± 0.13 

4.66 ± 0.26 

0.08 ± 0.01 

0.18 ± 0.03* 

0.096 ± 0.029 

0.042 ± 0.012 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

3.92 ± 0.33 

0.049 ± 0.013 

0.000 ± 0.000 

17.88 ± 0.97 

3.36 ± 0.26*d 

0.40 ± 0.07 

0.41 ± 0.06 

1.59 ± 0.19 

0.71 ± 0.13** 

0.35 ± 0.05 

0.60 ± 0.07 

1.61 ± 0.12 

0.53 ± 0.12 

1.52 ± 0.09 

5.34 ± 0.29 

0.09 ± 0.01 

0.13 ± 0.02 

0.079 ± 0.021 

0.050 ± 0.014 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

3.37 ± 0.23 

0.067 ± 0.020 

0.000 ± 0.000 

15.18 ± 1.10* 

3.50 ± 0.23**d 

0.50 ± 0.05 

0.44 ± 0.05 

1.28 ± 0.08** 

0.51 ± 0.10** 

0.36 ± 0.06 

0.74 ± 0.09 

1.58 ± 0.14 

0.62 ± 0.11 

1.25 ± 0.18 

4.31 ± 0.47 

0.11 ± 0.03 

0.14 ± 0.03 

0.060 ± 0.025 

0.058 ± 0.013 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

2.31 ± 0.15** 

0.081 ± 0.024 

0.000 ± 0.000 
AZT and AZT/"-Interferon A/D, NTP TR 469 231 

TABLE K1 

Hematology and Bone Marrow Data for Mice in the 14-Week Gavage Study of AZT 

Vehicle Control 50 mg/kg 100 mg/kg 200 mg/kg 800 mg/kg 2,000 mg/kg 

Male (continued) 

Bone Marrow Analyses (continued) 

Core Study (continued) 

n 

Megakaryo cells (10 )

6 

Plasma cells (10 )

6 

Mitotic figures (10 )

6 

Fat cells (10 )

6 

Mast cells (10 )

6 

Smudge cells (10 )

6 

Osteoblasts (10 )

6 

Osteoclasts (10 )

6 

Other bone marrow cells (10 )

6 

10 

0.019 ± 0.014 

0.011 ± 0.006 

0.29 ± 0.03 

0.000 ± 0.000 

0.000 ± 0.000 

0.58 ± 0.14 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

— 9 

0.024 ± 0.011 

0.020 ± 0.010 

0.20 ± 0.04 

0.000 ± 0.000 

0.000 ± 0.000 

0.45 ± 0.10 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

— 9 

0.031 ± 0.012 

0.009 ± 0.006 

0.28 ± 0.04 

0.000 ± 0.000 

0.000 ± 0.000 

0.70 ± 0.33 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

8 

0.025 ± 0.011 

0.031 ± 0.012 

0.26 ± 0.03 

0.000 ± 0.000 

0.000 ± 0.000 

0.51 ± 0.09 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

Recovery Study 

n 10 — 10 — 10 10 

Total femoral count (10 /femur) 24.3 ± 1.4 6 

M:E ratio 1.81 ± 0.12 

Rubriblasts (10 ) 0.45 ± 0.03 6 

Prorubricytes (10 ) 0.46 ± 0.08 6 

Rubricytes (10 ) 2.81 ± 0.29 6 

Metarubricytes (10 ) 2.51 ± 0.19 6 

Myeloblasts (10 ) 0.35 ± 0.04 6 

Promyelocytes (10 ) 0.70 ± 0.07 6 

Neutrophilic myelocytes (10 ) 3.11 ± 0.34 6 

Neutrophilic metamyelocytes (10 ) 0.039 ± 0.016 6 

Neutrophilic bands (10 ) 0.35 ± 0.07 6 

Neutrophilic segments (10 ) 6.17 ± 0.44 6 

Eosinophilic myelocytes (10 ) 0.14 ± 0.02 6 

Eosinophilic metamyelocytes (10 ) 0.07 ± 0.02 6 

Eosinophilic bands (10 ) 0.041 ± 0.011 6 

Eosinophilic segments (10 ) 0.066 ± 0.016 6 

Basophilic myelocytes (10 ) 0.000 ± 0.000 6 

Basophilic metamyelocytes (10 ) 0.000 ± 0.000 6 

Basophilic bands (10 ) 0.000 ± 0.000 6 

Basophilic segments (10 ) 0.000 ± 0.000 6 

Bone marrow lymphocytes (10 ) 4.17 ± 0.35 6 

Bone marrow macrophages (10 ) 0.11 ± 0.03 6 

Bone marrow monocytes (10 ) 0.000 ± 0.000 6 

Megakaryo cells (10 ) 0.028 ± 0.008 6 

Plasma cells (10 ) 0.020 ± 0.009 6 

Mitotic figures (10 ) 0.27 ± 0.05 6 

Fat cells (10 ) 0.000 ± 0.000 6 

Mast cells (10 ) 0.000 ± 0.000 6 

Smudge cells (10 ) 2.48 ± 0.31 6 

Osteoblasts (10 ) 0.000 ± 0.000 6 

Osteoclasts (10 ) 0.000 ± 0.000 6 

Other bone marrow cells (10 ) 0.000 ± 0.000 6 

25.1 ± 1.0 

1.83 ± 0.09 

0.47 ± 0.06 

0.42 ± 0.05 

2.91 ± 0.24 

2.52 ± 0.25 

0.39 ± 0.06 

0.62 ± 0.05 

3.26 ± 0.17 

0.069 ± 0.033 

0.42 ± 0.07 

6.18 ± 0.35 

0.18 ± 0.03 

0.12 ± 0.03 

0.045 ± 0.016 

0.103 ± 0.025 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

4.58 ± 0.36 

0.06 ± 0.02 

0.000 ± 0.000 

0.026 ± 0.009 

0.045 ± 0.016 

0.29 ± 0.03 

0.000 ± 0.000 

0.000 ± 0.000 

2.35 ± 0.15 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

25.2 ± 0.7 

1.67 ± 0.07 

0.44 ± 0.05 

0.42 ± 0.07 

3.35 ± 0.26 

2.52 ± 0.38 

0.37 ± 0.04 

0.63 ± 0.08 

3.09 ± 0.25 

0.036 ± 0.017 

0.26 ± 0.05 

6.37 ± 0.27 

0.19 ± 0.03 

0.09 ± 0.02 

0.036 ± 0.014 

0.076 ± 0.025 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

4.56 ± 0.19 

0.09 ± 0.02 

0.000 ± 0.000 

0.042 ± 0.011 

0.070 ± 0.021 

0.34 ± 0.04 

0.000 ± 0.000 

0.000 ± 0.000 

2.26 ± 0.16 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

27.0 ± 0.8 

1.50 ± 0.10 

0.50 ± 0.06 

0.48 ± 0.06 

3.74 ± 0.27* 

3.07 ± 0.44 

0.38 ± 0.04 

0.81 ± 0.10 

3.13 ± 0.25 

0.091 ± 0.020 

0.34 ± 0.04 

6.20 ± 0.27 

0.20 ± 0.03 

0.06 ± 0.01 

0.043 ± 0.011 

0.081 ± 0.018 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

4.63 ± 0.25 

0.09 ± 0.02 

0.000 ± 0.000 

0.042 ± 0.017 

0.052 ± 0.014 

0.29 ± 0.04 

0.000 ± 0.000 

0.000 ± 0.000 

2.76 ± 0.24 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 
232 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K1 

Hematology and Bone Marrow Data for Mice in the 14-Week Gavage Study of AZT 

Vehicle Control 50 mg/kg 100 mg/kg 200 mg/kg 800 mg/kg 2,000 mg/kg 

Female 

Hematology 

Core Study 

n 

Day 5 10 10 9 8 10 10 

Day 23 10 10 9 8 10 10 

Week 14 10 10 9 8 10 9 

Hematocrit (%) 

Day 5 47.1 ± 0.6 47.7 ± 0.7 46.0 ± 0.6 47.2 ± 0.9 45.1 ± 0.7 45.2 ± 0.5 

Day 23 46.7 ± 0.5 44.6 ± 0.6* 45.2 ± 0.5 43.5 ± 0.4** 42.3 ± 0.4** 40.6 ± 1.1** 

Week 14 48.3 ± 0.6 48.5 ± 0.6 47.6 ± 0.6 47.9 ± 0.6 45.7 ± 0.4** 43.4 ± 0.4** 

Hemoglobin (g/dL) 

Day 5 15.3 ± 0.2 15.6 ± 0.3 15.0 ± 0.2 15.6 ± 0.3 14.7 ± 0.2 14.8 ± 0.2 

Day 23 16.0 ± 0.2 15.3 ± 0.2* 15.6 ± 0.2 15.0 ± 0.2** 14.6 ± 0.1** 13.9 ± 0.4** 

Week 14 16.3 ± 0.2 16.3 ± 0.2 15.8 ± 0.1* 15.9 ± 0.2 15.0 ± 0.1** 14.0 ± 0.1** 

Erythrocytes (10 /μL) 6 

Day 5 9.56 ± 0.15 9.61 ± 0.16 9.36 ± 0.13 9.67 ± 0.20 9.04 ± 0.16* 9.08 ± 0.11* 

Day 23 9.83 ± 0.11 9.13 ± 0.10** 9.13 ± 0.11** 8.64 ± 0.10** 8.07 ± 0.08** 7.80 ± 0.19** 

Week 14 9.62 ± 0.10 9.03 ± 0.10** 8.66 ± 0.09** 8.39 ± 0.12** 7.36 ± 0.08** 6.50 ± 0.09** 

Reticulocytes (10 /μL) 6 

Day 5 

Day 23 

0.16 ± 0.02 

0.17 ± 0.02 

0.16 ± 0.02c 

0.19 ± 0.02 

0.13 ± 0.03b 

0.17 ± 0.02 

0.10 ± 0.01*b 

0.15 ± 0.02b 

0.06 ± 0.01**e 

0.17 ± 0.02 

0.04 ± 0.00**c 

0.22 ± 0.04 

Week 14 0.11 ± 0.01 0.11 ± 0.02 0.05 ± 0.01** 0.07 ± 0.01** 0.05 ± 0.01** 0.04 ± 0.01** 

Nucleated erythrocytes (10 /μL) 3 

Day 5 

Day 23 

0.07 ± 0.03 

0.00 ± 0.00 

0.04 ± 0.02 

0.01 ± 0.01 

0.06 ± 0.02 

0.02 ± 0.01d 

0.10 ± 0.03 

0.01 ± 0.01b 

0.01 ± 0.01 

0.00 ± 0.00 

0.03 ± 0.02 

0.01 ± 0.01 

Week 14 0.00 ± 0.00 0.01 ± 0.01 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.01 ± 0.01 

Mean cell volume (fL) 

Day 5 49.4 ± 0.2 49.8 ± 0.2 49.2 ± 0.3 48.8 ± 0.3 49.8 ± 0.2 49.8 ± 0.3 

Day 23 47.4 ± 0.3 48.8 ± 0.3** 49.6 ± 0.2** 50.5 ± 0.3** 52.4 ± 0.2** 52.1 ± 0.5** 

Week 14 50.3 ± 0.4 53.7 ± 0.3** 55.0 ± 0.3** 57.1 ± 0.4** 62.3 ± 0.6** 67.0 ± 0.7** 

Mean cell hemoglobin (pg) 

Day 5 16.0 ± 0.1 16.2 ± 0.0 16.1 ± 0.1 16.2 ± 0.1 16.3 ± 0.1 16.3 ± 0.1 

Day 23 16.3 ± 0.1 16.8 ± 0.1** 17.0 ± 0.1** 17.3 ± 0.1** 18.1 ± 0.1** 17.8 ± 0.2** 

Week 14 17.0 ± 0.1 18.0 ± 0.1** 18.3 ± 0.1** 18.9 ± 0.2** 20.4 ± 0.1** 21.5 ± 0.1** 

Mean cell hemoglobin concentration (g/dL) 

Day 5 32.5 ± 0.2 32.7 ± 0.2 32.7 ± 0.1 33.1 ± 0.2 32.7 ± 0.2 32.8 ± 0.1 

Day 23 34.3 ± 0.1 34.3 ± 0.2 34.4 ± 0.2 34.4 ± 0.1 34.4 ± 0.1 34.3 ± 0.1 

Week 14 33.8 ± 0.4 33.6 ± 0.3 33.3 ± 0.3 33.2 ± 0.2 32.8 ± 0.3* 32.3 ± 0.3** 

Platelets (10 /μL) 3 

Day 5 825.7 ± 64.6 793.6 ± 53.1 972.4 ± 31.0 868.6 ± 45.0 768.9 ± 38.7 871.4 ± 69.3 

Day 23 745.1 ± 21.8 808.6 ± 60.6 838.8 ± 32.3** 895.5 ± 41.4** 990.8 ± 36.6** 1,130.7 ± 54.9** 

Week 14 831.0 ± 29.1 913.6 ± 43.6 893.7 ± 49.9 874.8 ± 56.8 880.5 ± 26.3 878.7 ± 35.3 

Leukocytes (10 /μL) 3 

Day 5 5.98 ± 0.31 6.17 ± 0.32 5.94 ± 0.23 6.51 ± 0.46 5.67 ± 0.39 5.74 ± 0.37 

Day 23 6.92 ± 0.41 5.72 ± 0.18 6.12 ± 0.30 6.35 ± 0.48 5.90 ± 0.21 6.67 ± 0.71 

Week 14 6.37 ± 0.34 6.86 ± 0.32 7.03 ± 0.53 6.96 ± 0.54 6.21 ± 0.39 6.44 ± 0.30 

Segmented neutrophils (10 /μL) 3 

Day 5 0.81 ± 0.11 0.94 ± 0.21 0.78 ± 0.11 0.64 ± 0.13 0.38 ± 0.09** 0.68 ± 0.21* 

Day 23 0.72 ± 0.14 0.84 ± 0.16 0.73 ± 0.14 0.58 ± 0.07 0.50 ± 0.04 0.44 ± 0.06 

Week 14 0.70 ± 0.13 0.81 ± 0.11 0.86 ± 0.04 1.03 ± 0.22 0.71 ± 0.09 0.80 ± 0.10 

Lymphocytes (10 /μL) 3 

Day 5 4.95 ± 0.24 5.08 ± 0.21 4.96 ± 0.19 5.61 ± 0.39 5.14 ± 0.32 4.90 ± 0.29 

Day 23 6.07 ± 0.36 4.81 ± 0.13** 5.23 ± 0.21 5.74 ± 0.49 5.24 ± 0.18 6.16 ± 0.70 

Week 14 5.51 ± 0.36 5.77 ± 0.28 5.91 ± 0.48 5.71 ± 0.47 5.34 ± 0.31 5.41 ± 0.33 
AZT and AZT/"-Interferon A/D, NTP TR 469 233 

TABLE K1 

Hematology and Bone Marrow Data for Mice in the 14-Week Gavage Study of AZT 

Vehicle Control 50 mg/kg 100 mg/kg 200 mg/kg 800 mg/kg 2,000 mg/kg 

Female (continued) 

Hematology (continued) 

Core Study (continued) 

n 

Day 5 10 10 9 8 10 10 

Day 23 10 10 9 8 10 10 

Week 14 10 10 9 8 10 9 

Atypical lymphocytes (10 /μL) 3 

Day 5 0.01 ± 0.01 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.01 ± 0.01 0.00 ± 0.00 

Day 23 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 14 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Monocytes (10 /μL) 3 

Day 5 0.07 ± 0.03 0.03 ± 0.02 0.08 ± 0.03 0.03 ± 0.02 0.05 ± 0.02 0.07 ± 0.03 

Day 23 0.02 ± 0.01 0.02 ± 0.01 0.02 ± 0.02 0.00 ± 0.00 0.01 ± 0.01 0.03 ± 0.02 

Week 14 0.08 ± 0.03 0.08 ± 0.03 0.09 ± 0.04 0.06 ± 0.02 0.07 ± 0.03 0.10 ± 0.03 

Eosinophils (10 /μL) 3 

Day 5 0.15 ± 0.05 0.13 ± 0.03 0.12 ± 0.04 0.21 ± 0.04 0.13 ± 0.04 0.09 ± 0.02 

Day 23 0.12 ± 0.02 0.05 ± 0.02 0.16 ± 0.04 0.06 ± 0.02 0.12 ± 0.03 0.07 ± 0.03 

Week 14 0.09 ± 0.03 0.21 ± 0.04 0.21 ± 0.05 0.14 ± 0.05 0.10 ± 0.03 0.13 ± 0.02 

Recovery Study 

n 10 — 10 — 10 9 

Hematocrit (%) 

Week 14 47.5 ± 0.4 44.8 ± 0.6** 43.5 ± 0.8** 38.4 ± 0.6** 

Week 17 49.1 ± 0.7 49.2 ± 0.5 48.3 ± 0.5 47.2 ± 0.6 

Hemoglobin (g/dL) 

Week 14 15.9 ± 0.1 15.0 ± 0.2** 14.6 ± 0.3** 12.8 ± 0.2** 

Week 17 16.6 ± 0.2 16.6 ± 0.1 16.2 ± 0.1 15.8 ± 0.1** 

Erythrocytes (10 /μL) 6 

Week 14 9.97 ± 0.07 8.64 ± 0.13** 7.47 ± 0.14** 6.33 ± 0.12** 

Week 17 10.09 ± 0.12 9.93 ± 0.04 9.61 ± 0.13** 9.40 ± 0.10** 

Reticulocytes (10 /μL) 6 

Week 14 0.13 ± 0.01 0.14 ± 0.01 0.14 ± 0.01 0.15 ± 0.03 

Week 17 0.15 ± 0.02 0.11 ± 0.03 0.13 ± 0.01 0.13 ± 0.02 

Nucleated erythrocytes (10 /μL) 3 

Week 14 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00c 0.00 ± 0.00 

Week 17 0.01 ± 0.01 0.01 ± 0.01 0.01 ± 0.01 0.01 ± 0.01 

Mean cell volume (fL) 

Week 14 47.6 ± 0.2 51.8 ± 0.2** 58.2 ± 0.2** 60.7 ± 0.4** 

Week 17 48.7 ± 0.3 49.5 ± 0.4 50.4 ± 0.3** 50.3 ± 0.4** 

Mean cell hemoglobin (pg) 

Week 14 16.0 ± 0.1 17.4 ± 0.1** 19.6 ± 0.1** 20.2 ± 0.1** 

Week 17 16.4 ± 0.1 16.7 ± 0.1 17.0 ± 0.1** 16.8 ± 0.1* 

Mean cell hemoglobin concentration (g/dL) 

Week 14 33.5 ± 0.1 33.5 ± 0.1 33.6 ± 0.1 33.2 ± 0.2 

Week 17 33.8 ± 0.3 33.7 ± 0.2 33.7 ± 0.3 33.6 ± 0.2 

Platelets (10 /μL) 3 

Week 14 738.7 ± 32.6 924.5 ± 22.5** 1,015.7 ± 42.0** 1,337.4 ± 87.3** 

Week 17 918.4 ± 42.6 887.5 ± 49.9 916.7 ± 40.7 838.6 ± 49.6 

Leukocytes (10 /μL) 3 

Week 14 7.40 ± 0.47 7.18 ± 0.17 7.08 ± 0.42 6.38 ± 0.29 

Week 17 6.25 ± 0.29 7.04 ± 0.39 6.30 ± 0.31 5.74 ± 0.32 
234 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K1 

Hematology and Bone Marrow Data for Mice in the 14-Week Gavage Study of AZT 

Vehicle Control 50 mg/kg 100 mg/kg 200 mg/kg 800 mg/kg 2,000 mg/kg 

Female (continued) 

Hematology (continued) 

Recovery Study (continued) 

n 10 — 10 — 10 9 

Segmented neutrophils (10 /μL) 3 

Week 14 

Week 17 

Lymphocytes (10 /μL) 3 

Week 14 

Week 17 

Atypical lymphocytes (10 /μL) 3 

Week 14 

Week 17 

Monocytes (10 /μL) 3 

Week 14 

Week 17 

Eosinophils (10 /μL) 3 

Week 14 

Week 17 

0.76 ± 0.15 

1.02 ± 0.10 

6.44 ± 0.38 

5.16 ± 0.24 

0.00 ± 0.00 

0.00 ± 0.00 

0.03 ± 0.02 

0.02 ± 0.01 

0.18 ± 0.03 

0.08 ± 0.02 

0.68 ± 0.09 

1.03 ± 0.10 

6.35 ± 0.19 

5.84 ± 0.28 

0.00 ± 0.00 

0.00 ± 0.00 

0.03 ± 0.02 

0.02 ± 0.01 

0.14 ± 0.04 

0.17 ± 0.03 

0.56 ± 0.07 

1.01 ± 0.11 

6.34 ± 0.37 

5.20 ± 0.23 

0.00 ± 0.00 

0.00 ± 0.00 

0.01 ± 0.01 

0.03 ± 0.02 

0.17 ± 0.04 

0.09 ± 0.02 

0.54 ± 0.09 

0.90 ± 0.14 

5.69 ± 0.18 

4.73 ± 0.20 

0.00 ± 0.00 

0.00 ± 0.00 

0.01 ± 0.01 

0.02 ± 0.02 

0.17 ± 0.04 

0.10 ± 0.03 

Bone Marrow Analyses 

Core Study 

n 10 — 9 — 10 9 

Total femoral count 

(10 /femur) 6 

M:E ratio 

Rubriblasts (10 )

6 

Prorubricytes (10 )

6 

Rubricytes (10 )

6 

Metarubricytes (10 )

6 

Myeloblasts (10 )

6 

Promyelocytes (10 )

6 

Neutrophilic myelocytes (10 )

6 

Neutrophilic metamyelocytes (10 )

6 

Neutrophilic bands (10 )

6 

Neutrophilic segments (10 )

6 

Eosinophilic metamyelocytes (10 )

6 

Eosinophilic bands (10 )

6 

Eosinophilic myelocytes (10 )

6 

Eosinophilic segments (10 )

6 

Basophilic myelocytes (10 )

6 

Basophilic metamyelocytes (10 )

6 

Basophilic bands (10 )

6 

Basophilic segments (10 )

6 

Bone marrow lymphocytes (10 )

6 

Bone marrow macrophages (10 )

6 

Bone marrow monocytes (10 )

6 

Megakaryo cells (10 )

6 

Plasma cells (10 )

6 

Mitotic figures (10 )

6 

18.10 ± 1.43 

1.40 ± 0.06 

0.26 ± 0.06 

0.86 ± 0.14 

3.03 ± 0.35 

1.30 ± 0.23 

0.14 ± 0.03 

0.17 ± 0.03 

0.28 ± 0.03 

0.74 ± 0.11 

1.27 ± 0.14 

4.48 ± 0.38 

0.17 ± 0.04 

0.11 ± 0.03 

0.054 ± 0.018 

0.117 ± 0.019 

0.004 ± 0.004 

0.000 ± 0.000 

0.000 ± 0.000 

0.003 ± 0.003 

2.32 ± 0.16 

0.102 ± 0.017 

0.134 ± 0.024 

0.033 ± 0.012 

0.061 ± 0.022 

0.24 ± 0.04 

10.16 ± 1.58** 

2.11 ± 0.17** 

0.08 ± 0.03* 

0.30 ± 0.06** 

1.58 ± 0.33* 

0.40 ± 0.04** 

0.09 ± 0.02 

0.12 ± 0.02 

0.25 ± 0.04 

0.48 ± 0.13 

1.00 ± 0.24 

2.69 ± 0.49* 

0.11 ± 0.03 

0.14 ± 0.04 

0.049 ± 0.013 

0.106 ± 0.035 

0.000 ± 0.000 

0.004 ± 0.004 

0.000 ± 0.000 

0.008 ± 0.005 

1.63 ± 0.16* 

0.089 ± 0.025 

0.081 ± 0.024 

0.031 ± 0.011 

0.034 ± 0.009 

0.13 ± 0.02 

9.65 ± 0.93** 

3.04 ± 0.44** 

0.07 ± 0.02* 

0.33 ± 0.05* 

1.24 ± 0.22** 

0.32 ± 0.05** 

0.08 ± 0.01 

0.13 ± 0.01 

0.29 ± 0.04 

0.41 ± 0.09* 

0.93 ± 0.14 

3.02 ± 0.37* 

0.07 ± 0.01* 

0.10 ± 0.01 

0.039 ± 0.011 

0.083 ± 0.017 

0.000 ± 0.000 

0.000 ± 0.000 

0.004 ± 0.004 

0.003 ± 0.002 

1.34 ± 0.14** 

0.078 ± 0.020 

0.062 ± 0.013* 

0.031 ± 0.008 

0.045 ± 0.022 

0.16 ± 0.03 

7.60 ± 0.50** 

2.57 ± 0.28** 

0.09 ± 0.02 

0.30 ± 0.03* 

0.98 ± 0.12** 

0.19 ± 0.04** 

0.08 ± 0.01 

0.12 ± 0.02 

0.24 ± 0.03 

0.30 ± 0.05** 

0.60 ± 0.07* 

2.19 ± 0.20** 

0.06 ± 0.01* 

0.10 ± 0.02 

0.033 ± 0.007 

0.080 ± 0.012 

0.000 ± 0.000 

0.000 ± 0.000 

0.003 ± 0.002 

0.000 ± 0.000 

1.11 ± 0.13** 

0.056 ± 0.014 

0.048 ± 0.011** 

0.020 ± 0.005 

0.036 ± 0.012 

0.12 ± 0.02* 
AZT and AZT/"-Interferon A/D, NTP TR 469 235 

TABLE K1 

Hematology and Bone Marrow Data for Mice in the 14-Week Gavage Study of AZT 

Vehicle Control 50 mg/kg 100 mg/kg 200 mg/kg 800 mg/kg 2,000 mg/kg 

Female (continued) 

Bone Marrow Analyses (continued) 

Core Study (continued) 

n 10 — 9 — 10 9 

Fat cells (10 ) 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 6 

Mast cells (10 ) 0.003 ± 0.003 0.000 ± 0.000 0.000 ± 0.000 0.001 ± 0.001 6 

Smudge cells (10 ) 2.19 ± 0.26 0.76 ± 0.07** 0.80 ± 0.08** 0.76 ± 0.04** 6 

Osteoblasts (10 ) 0.016 ± 0.012 0.002 ± 0.002 0.000 ± 0.000 0.001 ± 0.001 6 

Osteoclasts (10 ) 0.003 ± 0.003 0.000 ± 0.000 0.004 ± 0.003 0.006 ± 0.003 6 

Other bone marrow cells (10 ) 0.012 ± 0.012 0.014 ± 0.012 0.024 ± 0.010 0.052 ± 0.020 6 

Recovery Study 

n 10 — 10 — 10 9 

Total femoral count (10 /femur) 18.9 ± 0.5 18.6 ± 1.0 20.5 ± 0.8 22.3 ± 0.9** 6 

M:E ratio 1.86 ± 0.19 1.91 ± 0.13 1.80 ± 0.12 1.98 ± 0.20 

Rubriblasts (10 ) 0.22 ± 0.03 0.14 ± 0.02 0.26 ± 0.05 0.22 ± 0.04 6 

Prorubricytes (10 ) 0.64 ± 0.08 0.75 ± 0.12 0.79 ± 0.07 0.63 ± 0.05 6 

Rubricytes (10 ) 2.73 ± 0.22 2.40 ± 0.16 3.08 ± 0.19 3.28 ± 0.27 6 

Metarubricytes (10 ) 1.24 ± 0.15 1.25 ± 0.14 1.24 ± 0.19 1.26 ± 0.10 6 

Myeloblasts (10 ) 0.27 ± 0.03 0.28 ± 0.03 0.32 ± 0.03 0.39 ± 0.04 6 

Promyelocytes (10 ) 0.62 ± 0.09 0.53 ± 0.07 0.68 ± 0.11 0.70 ± 0.08 6 

Neutrophilic myelocytes (10 ) 1.56 ± 0.10 1.31 ± 0.19 1.52 ± 0.09 1.72 ± 0.24 6 

Neutrophilic metamyelocytes (10 ) 0.523 ± 0.066 0.436 ± 0.078 0.594 ± 0.053 0.563 ± 0.072 6 

Neutrophilic bands (10 ) 1.55 ± 0.11 1.63 ± 0.12 1.85 ± 0.11 1.88 ± 0.20 6 

Neutrophilic segments (10 ) 3.58 ± 0.16 3.84 ± 0.27 4.02 ± 0.37 4.26 ± 0.31 6 

Eosinophilic myelocytes (10 ) 0.17 ± 0.04 0.17 ± 0.03 0.23 ± 0.02 0.20 ± 0.04 6 

Eosinophilic metamyelocytes (10 ) 0.07 ± 0.01 0.06 ± 0.01 0.07 ± 0.02 0.09 ± 0.02 6 

Eosinophilic bands (10 ) 0.120 ± 0.019 0.162 ± 0.030 0.130 ± 0.018 0.308 ± 0.035** 6 

Eosinophilic segments (10 ) 0.016 ± 0.007 0.030 ± 0.009 0.040 ± 0.017 0.029 ± 0.010 6 

Basophilic myelocytes (10 ) 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 6 

Basophilic metamyelocytes (10 ) 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 6 

Basophilic bands (10 ) 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 6 

Basophilic segments (10 ) 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 6 

Bone marrow lymphocytes (10 ) 3.71 ± 0.24 3.40 ± 0.21 4.09 ± 0.28 4.29 ± 0.31 6 

Bone marrow macrophages (10 ) 0.29 ± 0.03 0.29 ± 0.06 0.32 ± 0.08 0.31 ± 0.09 6 

Bone marrow monocytes (10 ) 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 6 

Megakaryo cells (10 ) 0.019 ± 0.011 0.019 ± 0.008 0.046 ± 0.016 0.026 ± 0.014 6 

Plasma cells (10 ) 0.053 ± 0.032 0.059 ± 0.016 0.037 ± 0.015 0.039 ± 0.018 6 

Mitotic figures (10 ) 0.27 ± 0.04 0.37 ± 0.05 0.35 ± 0.06 0.29 ± 0.05 6 

Fat cells (10 ) 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 6 

Mast cells (10 ) 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 6 

Smudge cells (10 ) 1.27 ± 0.27 1.51 ± 0.30 0.88 ± 0.30 1.81 ± 0.55 6 

Osteoblasts (10 ) 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 6 

Osteoclasts (10 ) 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 6 

Other bone marrow cells (10 ) 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 6 

* Significantly different (P#0.05) from the control group by Dunn’s or Shirley’s test 

** P#0.01 a Mean ± standard error. Statistical tests were performed on unrounded data. Bone marrow analyses were not performed on core study animals receiving 50 or 

200 mg/kg. The recovery study only included animals in the vehicle control, 100, 800, and 2,000 mg/kg groups. b n=7
 

n=9
 d n=10 e n=8 

c 
236 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K2 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZTa 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Male 

Hematology 

Clinical Pathology Groups 

n 

Week 14 10 10 9 10 

Week 27 10 10 10 10 

Week 40 10 9 10 9 

Week 54 10 10 10 10 

Week 66 9 10 10 9 

Week 80 10 9 8 10 

Hematocrit (%) 

Week 14 46.6 ± 0.4 45.6 ± 0.6 45.0 ± 0.9 45.5 ± 0.8 

Week 27 46.7 ± 0.6 44.6 ± 0.2* 45.5 ± 0.3 45.4 ± 0.5 

Week 40 43.1 ± 0.6 43.7 ± 0.8 43.7 ± 0.9 42.6 ± 1.2 

Week 54 40.4 ± 0.8 41.1 ± 0.6 40.5 ± 0.5 42.2 ± 1.2 

Week 66 44.4 ± 1.7 42.0 ± 1.1 42.6 ± 1.4 41.6 ± 0.5 

Week 80 44.9 ± 1.2 49.2 ± 3.3 41.5 ± 1.2 43.5 ± 2.3 

Hemoglobin (g/dL) 

Week 14 15.4 ± 0.1 15.0 ± 0.2 14.6 ± 0.2* 14.9 ± 0.2 

Week 27 15.5 ± 0.2 14.7 ± 0.1** 15.0 ± 0.1 15.1 ± 0.2 

Week 40 14.2 ± 0.2 14.4 ± 0.3 14.3 ± 0.3 14.2 ± 0.3 

Week 54 13.6 ± 0.3 13.9 ± 0.3 13.8 ± 0.2 14.1 ± 0.4 

Week 66 14.6 ± 0.6 13.9 ± 0.3 14.1 ± 0.5 13.9 ± 0.2 

Week 80 14.9 ± 0.4 16.3 ± 1.1 14.0 ± 0.3 14.5 ± 0.8 

Erythrocytes (10 /μL) 6 

Week 14 10.24 ± 0.09 9.70 ± 0.11** 9.35 ± 0.14** 9.29 ± 0.15** 

Week 27 10.33 ± 0.14 9.58 ± 0.07** 9.71 ± 0.07** 9.59 ± 0.11** 

Week 40 9.55 ± 0.10 9.18 ± 0.15 8.99 ± 0.15** 8.67 ± 0.19** 

Week 54 9.33 ± 0.17 8.89 ± 0.09* 8.68 ± 0.10** 8.89 ± 0.33** 

Week 66 9.87 ± 0.52 8.88 ± 0.37* 8.58 ± 0.34** 8.12 ± 0.11** 

Week 80 9.86 ± 0.40 10.41 ± 0.86 8.22 ± 0.20** 8.30 ± 0.50** 

Reticulocytes (10 /μL) 6 

Week 14 0.16 ± 0.01b 0.16 ± 0.01b 0.15 ± 0.01 0.10 ± 0.01**b 

Week 27 0.12 ± 0.01 0.10 ± 0.01 0.11 ± 0.01 0.10 ± 0.02 

Week 40 0.27 ± 0.02b 0.22 ± 0.02 0.24 ± 0.01 0.21 ± 0.02 

Week 54 0.23 ± 0.04 0.21 ± 0.03 0.18 ± 0.03 0.24 ± 0.04 

Week 66 0.33 ± 0.02 0.32 ± 0.02 0.31 ± 0.01 0.29 ± 0.01 

Week 80 0.20 ± 0.03 0.24 ± 0.03 0.18 ± 0.02 0.15 ± 0.03 

Nucleated erythrocytes (10 /μL) 3 

Week 14 0.01 ± 0.01 0.01 ± 0.01 0.02 ± 0.01 0.03 ± 0.01b 

Week 27 0.01 ± 0.01 0.06 ± 0.02* 0.02 ± 0.01 0.04 ± 0.01 

Week 40 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 54 0.01 ± 0.01 0.01 ± 0.01 0.00 ± 0.00 0.00 ± 0.00 

Week 66 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 80 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Mean cell volume (fL) 

Week 14 45.5 ± 0.3 47.0 ± 0.2** 48.1 ± 0.3** 49.0 ± 0.3** 

Week 27 45.2 ± 0.2 46.6 ± 0.2** 46.8 ± 0.2** 47.3 ± 0.2** 

Week 40 45.1 ± 0.5 47.6 ± 0.4** 48.6 ± 0.4* 49.1 ± 0.3** 

Week 54 43.4 ± 0.8 46.2 ± 0.6** 46.7 ± 0.4** 47.7 ± 0.6** 

Week 66 45.3 ± 1.0 47.6 ± 0.9* 49.8 ± 0.4** 51.2 ± 0.3** 

Week 80 45.8 ± 0.7 47.7 ± 0.9 50.4 ± 0.5** 52.6 ± 0.4** 
AZT and AZT/"-Interferon A/D, NTP TR 469 237 

TABLE K2 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Male (continued) 

Hematology (continued) 

Clinical Pathology Groups (continued) 

n 

Week 14 10 10 9 10 

Week 27 10 10 10 10 

Week 40 10 9 10 9 

Week 54 10 10 10 10 

Week 66 9 10 10 9 

Week 80 10 9 8 10 

Mean cell hemoglobin (pg) 

Week 14 15.0 ± 0.1 15.4 ± 0.1** 15.6 ± 0.1** 16.0 ± 0.1** 

Week 27 15.0 ± 0.1 15.4 ± 0.1** 15.5 ± 0.1** 15.8 ± 0.1** 

Week 40 14.8 ± 0.2 15.7 ± 0.1** 15.9 ± 0.1** 16.4 ± 0.1** 

Week 54 14.6 ± 0.3 15.7 ± 0.3* 15.9 ± 0.2** 15.9 ± 0.3** 

Week 66 14.9 ± 0.4 15.7 ± 0.3 16.5 ± 0.2** 17.1 ± 0.1** 

Week 80 15.2 ± 0.3 15.8 ± 0.3 17.0 ± 0.2** 17.5 ± 0.2** 

Mean cell hemoglobin concentration (g/dL) 

Week 14 33.0 ± 0.2 32.8 ± 0.2 32.6 ± 0.3 32.7 ± 0.1 

Week 27 33.3 ± 0.2 33.0 ± 0.2 33.1 ± 0.1 33.4 ± 0.1 

Week 40 32.9 ± 0.3 32.9 ± 0.2 32.7 ± 0.2 33.3 ± 0.2 

Week 54 33.7 ± 0.2 33.8 ± 0.2 34.1 ± 0.2 33.3 ± 0.3 

Week 66 32.9 ± 0.2 33.1 ± 0.3 33.0 ± 0.3 33.3 ± 0.3 

Week 80 33.2 ± 0.2 33.2 ± 0.1 33.8 ± 0.3 33.3 ± 0.2 

Platelets (10 /μL) 3 

Week 14 1,163.9 ± 52.5 1,215.3 ± 70.0 1,257.8 ± 70.8 1,249.2 ± 52.3 

Week 27 1,091.9 ± 60.9 1,270.0 ± 43.0 1,139.9 ± 48.8 1,136.6 ± 76.5 

Week 40 1,451.6 ± 40.3 1,557.6 ± 74.7 1,353.1 ± 69.6 1,450.4 ± 35.1 

Week 54 1,623.5 ± 201.3 1,458.7 ± 77.7 1,454.5 ± 73.8 1,574.0 ± 108.3 

Week 66 1,706.8 ± 108.2 1,806.5 ± 134.6 1,657.6 ± 53.9 1,802.3 ± 57.7 

Week 80 

Leukocytes (10 /μL) 3 1,709.6 ± 94.2 1,694.0 ± 161.6 1,807.4 ± 120.6 1,674.6 ± 121.7 

Week 14 6.28 ± 0.36 6.47 ± 0.46 6.71 ± 0.64 6.09 ± 0.29 

Week 27 7.33 ± 0.25 8.25 ± 0.54 8.31 ± 0.33 7.65 ± 0.23 

Week 40 8.57 ± 0.53 8.13 ± 0.62 7.34 ± 0.63 7.05 ± 0.44 

Week 54 10.82 ± 0.88 8.92 ± 0.72 9.40 ± 0.59 9.15 ± 0.91 

Week 66 10.64 ± 1.11 10.90 ± 0.77 9.30 ± 0.85 7.56 ± 0.84* 

Week 80 10.15 ± 0.96 9.56 ± 0.91 9.08 ± 0.89 8.14 ± 0.79 

Segmented neutrophils (10 /μL) 3 

Week 14 0.76 ± 0.10 0.82 ± 0.07 0.71 ± 0.13 0.72 ± 0.14b 

Week 27 1.62 ± 0.08 1.90 ± 0.22 1.72 ± 0.15 1.48 ± 0.19 

Week 40 2.09 ± 0.20 1.97 ± 0.28 1.61 ± 0.26 1.50 ± 0.21 

Week 54 3.18 ± 0.42 2.27 ± 0.27 2.04 ± 0.21 2.32 ± 0.38 

Week 66 2.01 ± 0.23 2.08 ± 0.18 1.84 ± 0.22 1.34 ± 0.12* 

Week 80 2.43 ± 0.42 2.40 ± 0.23 2.21 ± 0.62 1.73 ± 0.28 

Lymphocytes (10 /μL) 3 

Week 14 5.44 ± 0.32 5.55 ± 0.43 5.87 ± 0.56 5.31 ± 0.20b 

Week 27 5.38 ± 0.21 5.86 ± 0.35 6.18 ± 0.29 5.82 ± 0.29 

Week 40 6.35 ± 0.41 5.92 ± 0.41 5.59 ± 0.42 5.40 ± 0.24 

Week 54 7.14 ± 0.58 6.35 ± 0.52 6.99 ± 0.44 6.66 ± 0.67 

Week 66 8.09 ± 0.97 8.19 ± 0.56 7.04 ± 0.64 5.86 ± 0.66 

Week 80 7.60 ± 0.68 6.91 ± 0.78 6.79 ± 0.57 6.31 ± 0.59 
238 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K2 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Male (continued) 

Hematology (continued) 

Clinical Pathology Groups (continued) 

n 

Week 14 10 10 9 10 

Week 27 10 10 10 10 

Week 40 10 9 10 9 

Week 54 10 10 10 10 

Week 66 9 10 10 9 

Week 80 10 9 8 10 

Atypical lymphocytes (10 /μL) 3 

Week 14 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00b 

Week 27 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 40 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 54 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 66 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 80 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Monocytes (10 /μL) 3 

Week 14 0.04 ± 0.01 0.04 ± 0.02 0.09 ± 0.03 0.02 ± 0.01b 

Week 27 0.18 ± 0.05 0.22 ± 0.06 0.17 ± 0.06 0.16 ± 0.04 

Week 40 0.05 ± 0.02 0.04 ± 0.02 0.03 ± 0.02 0.03 ± 0.02 

Week 54 0.24 ± 0.11 0.11 ± 0.04 0.24 ± 0.07 0.08 ± 0.03 

Week 66 0.44 ± 0.07 0.51 ± 0.08 0.30 ± 0.05 0.22 ± 0.06* 

Week 80 0.08 ± 0.04 0.18 ± 0.06 0.05 ± 0.03 0.04 ± 0.02 

Eosinophils (10 /μL) 3 

Week 14 0.04 ± 0.01 0.06 ± 0.02 0.05 ± 0.02 0.02 ± 0.02b 

Week 27 0.15 ± 0.02 0.27 ± 0.09 0.23 ± 0.04 0.20 ± 0.03 

Week 40 0.09 ± 0.02 0.20 ± 0.06 0.12 ± 0.03 0.11 ± 0.03 

Week 54 0.25 ± 0.09 0.19 ± 0.09 0.12 ± 0.04 0.10 ± 0.03 

Week 66 0.10 ± 0.04 0.13 ± 0.03 0.12 ± 0.03 0.14 ± 0.03 

Week 80 0.03 ± 0.01 0.07 ± 0.03 0.04 ± 0.02 0.05 ± 0.02 

Core Groups 

n 10 10 6 10 

Hematocrit (%) 38.1 ± 0.8 40.0 ± 2.1 35.3 ± 1.8 45.4 ± 3.8 

Hemoglobin (g/dL) 

Erythrocytes (10 /μL) 6 

Reticulocytes (10 /μL) 6 

Nucleated erythrocytes (10 /μL) 3 

13.2 ± 0.4 

8.48 ± 0.30 

0.25 ± 0.04 

0.00 ± 0.00 

13.6 ± 0.7 

8.94 ± 0.61 

0.34 ± 0.07 

0.00 ± 0.00 

12.0 ± 0.8 

7.14 ± 0.58 

0.23 ± 0.05 

0.00 ± 0.00 

15.1 ± 1.3 

9.09 ± 0.79 

0.35 ± 0.07 

0.00 ± 0.00 

Mean cell volume (fL) 45.2 ± 0.7 45.2 ± 0.8 50.4 ± 2.5* 50.0 ± 0.7** 

Mean cell hemoglobin (pg) 15.6 ± 0.2 15.4 ± 0.3 17.0 ± 0.6* 16.7 ± 0.2** 

Mean cell hemoglobin 

concentration (g/dL) 

Platelets (10 /μL) 3 

Leukocytes (10 /μL) 3 

Segmented neutrophils (10 /μL) 3 

Lymphocytes (10 /μL) 3 

Atypical lymphocytes (10 /μL) 3 

Monocytes (10 /μL) 3 

Eosinophils (10 /μL) 3 

34.6 ± 0.3 

1,753.6 ± 77.7 

7.35 ± 0.75 

2.44 ± 0.25 

4.57 ± 0.53 

0.01 ± 0.01 

0.25 ± 0.06 

0.07 ± 0.02 

34.1 ± 0.3 

2,045.9 ± 107.6* 

9.86 ± 0.55 

3.12 ± 0.23 

6.27 ± 0.54 

0.00 ± 0.00 

0.42 ± 0.05 

0.06 ± 0.03 

33.8 ± 0.6 

2,106.2 ± 149.2* 

8.61 ± 1.54 

2.22 ± 0.29 

5.88 ± 1.28 

0.09 ± 0.09 

0.33 ± 0.09 

0.09 ± 0.04 

33.4 ± 0.3** 

2,349.7 ± 191.1** 

10.36 ± 0.81* 

3.71 ± 0.67 

5.90 ± 0.48 

0.00 ± 0.00 

0.58 ± 0.18 

0.17 ± 0.05 
AZT and AZT/"-Interferon A/D, NTP TR 469 239 

TABLE K2 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Male (continued) 

Bone Marrow Analyses 

Clinical Pathology Groups 

n 

Week 54 10 10 10 10 

Week 66 9 10 9 8 

Week 80 10 9 8 10 

Total femoral count (10 /femur) 6 

Week 54 32.1 ± 1.7 28.4 ± 1.6 29.1 ± 1.2 29.2 ± 1.4 

Week 66 34.1 ± 2.1 34.9 ± 1.4 32.9 ± 0.9 33.5 ± 1.5 

Week 80 35.7 ± 1.6 34.4 ± 1.4 32.0 ± 1.2 32.2 ± 1.3 

M:E ratio 

Week 54 1.59 ± 0.21 1.87 ± 0.12 2.06 ± 0.23 1.97 ± 0.07 

Week 66 2.20 ± 0.20 2.13 ± 0.19 2.04 ± 0.19 2.21 ± 0.13 

Week 80 2.84 ± 0.23 2.72 ± 0.22 3.29 ± 0.42 3.00 ± 0.36 

Rubriblasts (10 )

6 

Week 54 0.80 ± 0.08 0.69 ± 0.12 0.70 ± 0.07 0.85 ± 0.07 

Week 66 0.58 ± 0.08 0.57 ± 0.06 0.71 ± 0.10 0.74 ± 0.07 

Week 80 0.31 ± 0.05 0.26 ± 0.03 0.24 ± 0.04 0.34 ± 0.04 

Prorubricytes (10 )

6 

Week 54 0.53 ± 0.11 0.63 ± 0.09 0.53 ± 0.05 0.79 ± 0.09 

Week 66 0.48 ± 0.08 0.57 ± 0.07 0.67 ± 0.13 0.31 ± 0.03 

Week 80 0.93 ± 0.10 0.97 ± 0.13 0.87 ± 0.14 0.87 ± 0.11 

Rubricytes (10 )

6 

Week 54 5.73 ± 0.49 4.17 ± 0.28* 3.57 ± 0.41** 3.47 ± 0.27** 

Week 66 3.74 ± 0.28 4.13 ± 0.31 3.73 ± 0.32 3.82 ± 0.42 

Week 80 3.66 ± 0.32 3.92 ± 0.51 3.27 ± 0.49 3.44 ± 0.39 

Metarubricytes (10 )

6 

Week 54 2.87 ± 0.24 1.55 ± 0.20** 1.95 ± 0.24* 1.85 ± 0.16* 

Week 66 2.37 ± 0.18 2.28 ± 0.20 2.47 ± 0.19 2.18 ± 0.20 

Week 80 1.85 ± 0.18 1.80 ± 0.08 1.15 ± 0.08* 1.42 ± 0.21 

Myeloblasts (10 )

6 

Week 54 1.12 ± 0.12 0.36 ± 0.06** 0.33 ± 0.04** 0.27 ± 0.05** 

Week 66 0.63 ± 0.08 0.72 ± 0.09 0.56 ± 0.07 0.65 ± 0.07 

Week 80 0.56 ± 0.06 0.54 ± 0.06 0.40 ± 0.08 0.66 ± 0.07 

Promyelocytes (10 )

6 

Week 54 0.52 ± 0.09 0.76 ± 0.13 0.71 ± 0.08 0.58 ± 0.09 

Week 66 0.46 ± 0.06 0.42 ± 0.09 0.42 ± 0.09 0.59 ± 0.12 

Week 80 0.68 ± 0.09 0.66 ± 0.09 0.69 ± 0.08 0.89 ± 0.09 

Neutrophilic myelocytes (10 )

6 

Week 54 1.06 ± 0.16 0.96 ± 0.12 0.95 ± 0.07 1.23 ± 0.10 

Week 66 1.75 ± 0.15 1.57 ± 0.14 1.27 ± 0.07** 1.14 ± 0.12** 

Week 80 1.17 ± 0.21 1.04 ± 0.12 1.45 ± 0.18 1.31 ± 0.17 

Neutrophilic metamyelocytes (10 )

6 

Week 54 5.40 ± 0.55 4.23 ± 0.21 4.41 ± 0.30 4.65 ± 0.38 

Week 66 4.07 ± 0.49 4.42 ± 0.38 4.12 ± 0.32 4.30 ± 0.33 

Week 80 1.49 ± 0.25 1.31 ± 0.17 0.78 ± 0.21 1.04 ± 0.18 

Neutrophilic bands (10 )

6 

Week 54 0.41 ± 0.05 0.31 ± 0.08 0.44 ± 0.06 0.34 ± 0.05 

Week 66 0.39 ± 0.10 0.48 ± 0.05 0.45 ± 0.07 0.51 ± 0.07 

Week 80 1.86 ± 0.40 1.44 ± 0.31 1.33 ± 0.30 1.15 ± 0.24 
240 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K2 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Male (continued) 

Bone Marrow Analyses (continued) 

Clinical Pathology Groups (continued) 

n 

Week 54 10 10 10 10 

Week 66 9 10 9 8 

Week 80 10 9 8 10 

Neutrophilic segments (10 )

6 

Week 54 5.54 ± 0.47 5.65 ± 0.47 5.51 ± 0.22 6.02 ± 0.32 

Week 66 7.50 ± 0.86 7.26 ± 0.53 7.52 ± 0.38 7.44 ± 0.36 

Week 80 12.05 ± 0.63 12.30 ± 0.77 11.63 ± 0.89 11.06 ± 0.35 

Eosinophilic myelocytes (10 )

6 

Week 54 0.129 ± 0.034 0.058 ± 0.024 0.061 ± 0.026 0.077 ± 0.021 

Week 66 0.086 ± 0.050 0.055 ± 0.025 0.022 ± 0.011 0.044 ± 0.013 

Week 80 0.023 ± 0.012 0.062 ± 0.018 0.049 ± 0.016 0.048 ± 0.024 

Eosinophilic metamyelocytes (10 )

6 

Week 54 0.23 ± 0.05 0.22 ± 0.07 0.21 ± 0.05 0.25 ± 0.04 

Week 66 0.25 ± 0.04 0.19 ± 0.05 0.17 ± 0.03 0.18 ± 0.03 

Week 80 0.08 ± 0.03 0.09 ± 0.03 0.03 ± 0.01 0.04 ± 0.01 

Eosinophilic bands (10 )

6 

Week 54 0.12 ± 0.03 0.16 ± 0.05 0.10 ± 0.04 0.11 ± 0.03 

Week 66 0.14 ± 0.04 0.11 ± 0.02 0.16 ± 0.04 0.11 ± 0.02 

Week 80 0.27 ± 0.04 0.21 ± 0.05 0.16 ± 0.02 0.19 ± 0.05 

Eosinophilic segments (10 )

6 

Week 54 0.11 ± 0.04 0.10 ± 0.03 0.13 ± 0.03 0.09 ± 0.03 

Week 66 0.27 ± 0.07 0.13 ± 0.03 0.22 ± 0.04 0.22 ± 0.08 

Week 80 0.22 ± 0.04 0.26 ± 0.05 0.21 ± 0.04 0.23 ± 0.04 

Basophilic myelocytes (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 80 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic metamyelocytes (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 80 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic bands (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 80 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic segments (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 80 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Bone marrow lymphocytes (10 )

6 

Week 54 3.43 ± 0.51 3.88 ± 0.21 4.36 ± 0.53 4.03 ± 0.45 

Week 66 4.57 ± 0.55 4.93 ± 0.37 3.95 ± 0.28 4.52 ± 0.31 

Week 80 4.58 ± 0.64 3.95 ± 0.25 4.21 ± 0.29 4.43 ± 0.50 

Bone marrow macrophages (10 )

6 

Week 54 0.19 ± 0.07 0.14 ± 0.03 0.12 ± 0.03 0.14 ± 0.03 

Week 66 0.27 ± 0.04 0.21 ± 0.05 0.19 ± 0.02 0.31 ± 0.04 

Week 80 0.18 ± 0.04 0.20 ± 0.05 0.19 ± 0.05 0.22 ± 0.02 

Bone marrow monocytes (10 )

6 

Week 54 0.00 ± 0.00 0.00 ± 0.00 0.01 ± 0.01 0.00 ± 0.00 

Week 66 0.00 ± 0.00 0.00 ± 0.00 0.01 ± 0.01 0.00 ± 0.00 

Week 80 0.33 ± 0.06 0.21 ± 0.05 0.19 ± 0.05 0.21 ± 0.03 
AZT and AZT/"-Interferon A/D, NTP TR 469 241 

TABLE K2 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Male (continued) 

Bone Marrow Analyses (continued) 

Clinical Pathology Groups (continued) 

n 

Week 54 10 10 10 10 

Week 66 9 10 9 8 

Week 80 10 9 8 10 

Megakaryo cells (10 )

6 

Week 54 0.064 ± 0.018 0.040 ± 0.017 0.045 ± 0.015 0.054 ± 0.011 

Week 66 0.15 ± 0.03 0.13 ± 0.03 0.09 ± 0.02 0.16 ± 0.04 

Week 80 0.11 ± 0.03 0.08 ± 0.02 0.13 ± 0.03 0.15 ± 0.04 

Plasma cells (10 )

6 

Week 54 0.13 ± 0.05 0.12 ± 0.01 0.25 ± 0.05* 0.13 ± 0.02 

Week 66 0.16 ± 0.04 0.21 ± 0.03 0.21 ± 0.03 0.20 ± 0.03 

Week 80 0.33 ± 0.07 0.28 ± 0.05 0.38 ± 0.08 0.33 ± 0.11 

Mitotic figures (10 )

6 

Week 54 0.31 ± 0.06 0.49 ± 0.07* 0.54 ± 0.09* 0.65 ± 0.07** 

Week 66 0.24 ± 0.04 0.26 ± 0.05 0.21 ± 0.06 0.27 ± 0.06 

Week 80 0.18 ± 0.05 0.11 ± 0.03 0.17 ± 0.04 0.20 ± 0.03 

Fat cells (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 80 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Mast cells (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.006 ± 0.006 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 80 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Smudge cells (10 )

6 

Week 54 3.43 ± 0.27 3.88 ± 0.29 4.18 ± 0.34 3.66 ± 0.31 

Week 66 6.01 ± 0.56 6.24 ± 0.27 5.74 ± 0.41 5.73 ± 0.48 

Week 80 4.82 ± 0.27 4.71 ± 0.32 4.45 ± 0.25 4.01 ± 0.25 

Osteoblasts (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 80 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Osteoclasts (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.012 ± 0.008 

Week 66 0.033 ± 0.013 0.044 ± 0.017 0.028 ± 0.015 0.033 ± 0.012 

Week 80 0.000 ± 0.000 0.006 ± 0.006 0.000 ± 0.000 0.000 ± 0.000 

Other bone marrow cells (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 80 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Neutrophilic hypersegments (10 )

6 

Week 54 0.11 ± 0.04 0.13 ± 0.05 0.13 ± 0.03 0.25 ± 0.04* 

Week 66 0.35 ± 0.06 0.20 ± 0.04 0.42 ± 0.07 0.29 ± 0.06 

Week 80 0.11 ± 0.08 0.25 ± 0.15 0.21 ± 0.06 0.13 ± 0.04 
242 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K2 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Male (continued) 

Bone Marrow Analyses (continued) 

Core Groups 

n 10 9 6 8 

Total femoral count (10 /femur) 6 31.4 ± 2.3 28.7 ± 2.2 30.2 ± 2.9 29.3 ± 1.5 

M:E ratio 2.59 ± 0.36 1.81 ± 0.23 2.53 ± 0.48 2.31 ± 0.29 

Rubriblasts (10 )

6 

Prorubricytes (10 )

6 

Rubricytes (10 )

6 

Metarubricytes (10 )

6 

Myeloblasts (10 )

6 

Promyelocytes (10 )

6 

Neutrophilic myelocytes (10 )

6 

Neutrophilic metamyelocytes (10 )

6 

Neutrophilic bands (10 )

6 

Neutrophilic segments (10 )

6 

Eosinophilic myelocytes (10 )

6 

Eosinophilic metamyelocytes (10 )

6 

Eosinophilic bands (10 )

6 

Eosinophilic segments (10 )

6 

Basophilic myelocytes (10 )

6 

Basophilic metamyelocytes (10 )

6 

Basophilic bands (10 )

6 

Basophilic segments (10 )

6 

Bone marrow lymphocytes (10 )

6 

Bone marrow macrophages (10 )

6 

Bone marrow monocytes (10 )

6 

Megakaryo cells (10 )

6 

Plasma cells (10 )

6 

Mitotic figures (10 )

6 

Fat cells (10 )

6 

Mast cells (10 )

6 

Smudge cells (10 )

6 

Osteoblasts (10 )

6 

Osteoclasts (10 )

6 

Other bone marrow cells (10 )

6 

0.39 ± 0.03 

0.84 ± 0.09 

4.10 ± 0.34 

1.59 ± 0.28 

0.33 ± 0.03 

0.54 ± 0.07 

1.55 ± 0.23 

1.18 ± 0.24 

3.66 ± 0.42 

8.55 ± 0.98 

0.076 ± 0.030 

0.067 ± 0.025 

0.23 ± 0.05 

0.13 ± 0.05 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

4.14 ± 0.60 

0.28 ± 0.05 

0.52 ± 0.17 

0.06 ± 0.01 

0.33 ± 0.07 

0.23 ± 0.04 

0.000 ± 0.000 

0.000 ± 0.000 

2.56 ± 0.20 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.42 ± 0.08 

1.31 ± 0.26 

4.33 ± 0.36 

2.23 ± 0.37 

0.37 ± 0.04 

0.50 ± 0.07 

1.29 ± 0.18 

0.95 ± 0.18 

3.15 ± 0.42 

7.44 ± 0.94 

0.027 ± 0.011 

0.084 ± 0.032 

0.17 ± 0.03 

0.13 ± 0.04 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

2.82 ± 0.60 

0.15 ± 0.04 

0.24 ± 0.05 

0.09 ± 0.02 

0.36 ± 0.09 

0.14 ± 0.03 

0.000 ± 0.000 

0.000 ± 0.000 

2.48 ± 0.42 

0.000 ± 0.000 

0.003 ± 0.003 

0.000 ± 0.000 

0.41 ± 0.08 

1.17 ± 0.28 

3.86 ± 0.96 

2.00 ± 0.45 

0.36 ± 0.06 

0.57 ± 0.09 

1.45 ± 0.16 

0.86 ± 0.16 

4.48 ± 0.69 

6.95 ± 0.49 

0.058 ± 0.025 

0.025 ± 0.018 

0.20 ± 0.07 

0.12 ± 0.03 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

3.59 ± 0.47 

0.13 ± 0.02 

0.38 ± 0.06 

0.06 ± 0.02 

0.36 ± 0.12 

0.24 ± 0.10 

0.000 ± 0.000 

0.000 ± 0.000 

2.87 ± 0.63 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.40 ± 0.08 

1.26 ± 0.09 

3.86 ± 0.45 

1.51 ± 0.15 

0.25 ± 0.03 

0.46 ± 0.06 

1.43 ± 0.27 

1.21 ± 0.12 

3.87 ± 0.45 

7.65 ± 0.98 

0.056 ± 0.016 

0.068 ± 0.015 

0.27 ± 0.05 

0.13 ± 0.04 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

2.32 ± 0.26 

0.26 ± 0.06 

0.32 ± 0.07 

0.14 ± 0.04 

0.50 ± 0.13 

0.16 ± 0.04 

0.000 ± 0.000 

0.000 ± 0.000 

3.12 ± 0.36 

0.000 ± 0.000 

0.008 ± 0.008 

0.000 ± 0.000 
AZT and AZT/"-Interferon A/D, NTP TR 469 243 

TABLE K2 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Female 

Hematology 

Clinical Pathology Groups 

n 

Week 14 10 10 9 9 

Week 27 10 9 10 9 

Week 40 10 10 10 9 

Week 54 10 10 10 10 

Week 66 10 9 10 10 

Week 80 10 9 9 9 

Hematocrit (%) 

Week 14 46.0 ± 0.7 44.9 ± 0.5 44.8 ± 0.6 44.0 ± 0.6 

Week 27 46.5 ± 0.5 46.1 ± 0.4 45.3 ± 0.5 46.6 ± 0.4 

Week 40 45.5 ± 0.6 44.3 ± 0.3 44.2 ± 0.4 43.6 ± 0.7 

Week 54 44.0 ± 0.3 44.2 ± 0.3 42.4 ± 0.2** 43.0 ± 0.6 

Week 66 43.1 ± 2.8 43.5 ± 0.7 44.7 ± 1.0 42.8 ± 0.3** 

Week 80 48.3 ± 2.3 48.3 ± 3.2 44.8 ± 0.3** 43.6 ± 0.6** 

Hemoglobin (g/dL) 

Week 14 15.2 ± 0.2 14.9 ± 0.1 14.8 ± 0.2 14.6 ± 0.2* 

Week 27 15.4 ± 0.1 15.2 ± 0.1 15.0 ± 0.2 15.3 ± 0.1 

Week 40 15.0 ± 0.2 14.7 ± 0.1 14.7 ± 0.1 14.3 ± 0.2* 

Week 54 14.8 ± 0.1 14.9 ± 0.1 14.5 ± 0.1 14.3 ± 0.2* 

Week 66 14.3 ± 0.9 14.3 ± 0.2 14.6 ± 0.3 14.0 ± 0.1** 

Week 80 16.2 ± 0.7 16.1 ± 1.1 14.9 ± 0.1** 14.3 ± 0.2** 

Erythrocytes (10 /μL) 6 

Week 14 10.03 ± 0.13 9.30 ± 0.09** 9.13 ± 0.11** 8.80 ± 0.12** 

Week 27 10.24 ± 0.09 9.97 ± 0.09* 9.73 ± 0.10** 9.76 ± 0.06** 

Week 40 9.75 ± 0.10 9.10 ± 0.08** 8.92 ± 0.09** 8.65 ± 0.14** 

Week 54 9.67 ± 0.07 9.21 ± 0.07** 8.76 ± 0.06** 8.58 ± 0.09** 

Week 66 8.91 ± 0.51 8.46 ± 0.13** 8.56 ± 0.19** 8.00 ± 0.07** 

Week 80 9.96 ± 0.66 9.24 ± 0.60* 8.49 ± 0.04** 8.18 ± 0.11** 

Reticulocytes (10 /μL) 6 

Week 14 0.20 ± 0.02b 0.19 ± 0.01 0.17 ± 0.01 0.17 ± 0.01 

Week 27 0.15 ± 0.02 0.15 ± 0.01c 0.13 ± 0.01 0.16 ± 0.02 

Week 40 0.23 ± 0.01 0.25 ± 0.02 0.30 ± 0.03* 0.36 ± 0.02** 

Week 54 0.24 ± 0.03 0.24 ± 0.02 0.13 ± 0.01** 0.18 ± 0.02 

Week 66 0.25 ± 0.02 0.27 ± 0.02 0.27 ± 0.02 0.28 ± 0.01 

Week 80 0.22 ± 0.04 0.19 ± 0.03 0.18 ± 0.02 0.19 ± 0.02 

Nucleated erythrocytes (10 /μL) 3 

Week 14 0.03 ± 0.01b 0.02 ± 0.01 0.03 ± 0.01 0.04 ± 0.02 

Week 27 0.01 ± 0.01 0.00 ± 0.00 0.01 ± 0.01 0.00 ± 0.00 

Week 40 0.01 ± 0.01 0.00 ± 0.00 0.00 ± 0.00 0.01 ± 0.01 

Week 54 0.01 ± 0.01 0.00 ± 0.00 0.01 ± 0.01 0.01 ± 0.01 

Week 66 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 80 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Mean cell volume (fL) 

Week 14 45.9 ± 0.3 48.3 ± 0.2** 49.1 ± 0.2** 50.0 ± 0.2** 

Week 27 45.4 ± 0.3 46.2 ± 0.4 46.6 ± 0.3* 47.8 ± 0.3** 

Week 40 46.7 ± 0.3 48.7 ± 0.3** 49.5 ± 0.2** 50.4 ± 0.3** 

Week 54 45.4 ± 0.1 48.0 ± 0.2** 48.5 ± 0.2** 50.2 ± 0.3** 

Week 66 48.1 ± 0.7 51.5 ± 0.3** 52.3 ± 0.4** 53.5 ± 0.4** 

Week 80 48.9 ± 0.7 52.2 ± 0.3** 52.7 ± 0.3** 53.3 ± 0.6** 
244 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K2 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Female (continued) 

Hematology (continued) 

Clinical Pathology Groups (continued) 

n 

Week 14 10 10 9 9 

Week 27 10 9 10 9 

Week 40 10 10 10 9 

Week 54 10 10 10 10 

Week 66 10 9 10 10 

Week 80 10 9 9 9 

Mean cell hemoglobin (pg) 

Week 14 15.1 ± 0.1 16.0 ± 0.1** 16.2 ± 0.1** 16.6 ± 0.1** 

Week 27 15.1 ± 0.1 15.2 ± 0.1 15.4 ± 0.1* 15.7 ± 0.1** 

Week 40 15.4 ± 0.1 16.1 ± 0.0** 16.5 ± 0.0** 16.6 ± 0.1** 

Week 54 15.3 ± 0.1 16.2 ± 0.1** 16.5 ± 0.1** 16.7 ± 0.1** 

Week 66 15.9 ± 0.2 16.9 ± 0.1** 17.1 ± 0.1** 17.6 ± 0.1** 

Week 80 16.4 ± 0.3 17.4 ± 0.1** 17.6 ± 0.1** 17.4 ± 0.2** 

Mean cell hemoglobin concentration (g/dL) 

Week 14 33.1 ± 0.2 33.1 ± 0.2 33.0 ± 0.1 33.2 ± 0.1 

Week 27 33.2 ± 0.2 33.0 ± 0.2 33.0 ± 0.1 32.7 ± 0.2 

Week 40 33.0 ± 0.2 33.1 ± 0.2 33.2 ± 0.1 32.9 ± 0.2 

Week 54 33.7 ± 0.1 33.7 ± 0.1 34.1 ± 0.1 33.2 ± 0.1 

Week 66 33.2 ± 0.1 32.8 ± 0.1 32.7 ± 0.1 32.8 ± 0.2 

Week 80 33.5 ± 0.2 33.4 ± 0.1 33.4 ± 0.2 32.7 ± 0.2* 

Platelets (10 /μL) 3 

Week 14 980.5 ± 45.4 1,088.9 ± 47.7 1,075.0 ± 40.6 1,178.2 ± 78.1 

Week 27 883.7 ± 54.6 953.7 ± 43.3 1,069.1 ± 71.3 1,020.4 ± 43.6 

Week 40 1,158.3 ± 52.6 1,221.8 ± 40.7 1,302.7 ± 33.7* 1,409.1 ± 71.3** 

Week 54 1,095.2 ± 51.2 1,118.4 ± 58.7 1,175.9 ± 65.2 1,268.0 ± 103.2 

Week 66 1,132.2 ± 70.2 1,343.9 ± 84.0 1,361.6 ± 49.7* 1,416.5 ± 42.2** 

Week 80 

Leukocytes (10 /μL) 3 1,096.2 ± 60.8 1,185.2 ± 106.5 1,182.8 ± 26.6 1,478.6 ± 97.2** 

Week 14 5.79 ± 0.29 5.81 ± 0.36 6.00 ± 0.41 5.32 ± 0.39 

Week 27 6.06 ± 0.32 6.88 ± 0.29 6.36 ± 0.55 5.86 ± 0.61 

Week 40 6.88 ± 0.41 4.97 ± 0.40** 6.36 ± 0.27 5.56 ± 0.27 

Week 54 6.65 ± 0.33 6.59 ± 0.35 6.44 ± 0.24 6.34 ± 0.31 

Week 66 4.60 ± 0.33 4.49 ± 0.25 4.50 ± 0.23 4.60 ± 0.20 

Week 80 6.94 ± 0.46 5.68 ± 0.37 5.98 ± 0.54 6.09 ± 0.52 

Segmented neutrophils (10 /μL) 3 

Week 14 1.22 ± 0.16b 1.10 ± 0.15 0.82 ± 0.08 0.85 ± 0.11 

Week 27 1.27 ± 0.15 1.22 ± 0.16 1.33 ± 0.21 1.05 ± 0.14 

Week 40 1.34 ± 0.19 0.98 ± 0.10 1.17 ± 0.16 1.04 ± 0.09 

Week 54 1.65 ± 0.18 1.42 ± 0.13 1.61 ± 0.08 1.61 ± 0.17 

Week 66 1.14 ± 0.21 0.87 ± 0.06 0.91 ± 0.08 0.90 ± 0.10 

Week 80 1.31 ± 0.11 2.09 ± 0.39 1.21 ± 0.25 1.11 ± 0.18 

Lymphocytes (10 /μL) 3 

Week 14 4.37 ± 0.23b 4.59 ± 0.30 4.99 ± 0.37 4.31 ± 0.36 

Week 27 4.60 ± 0.23 5.46 ± 0.32 4.81 ± 0.42 4.63 ± 0.46 

Week 40 5.42 ± 0.29 3.85 ± 0.34** 5.07 ± 0.22 4.42 ± 0.24 

Week 54 4.53 ± 0.28 4.91 ± 0.34 4.48 ± 0.25 4.31 ± 0.27 

Week 66 3.25 ± 0.36 3.42 ± 0.20 3.36 ± 0.16 3.49 ± 0.15 

Week 80 5.47 ± 0.51 3.34 ± 0.50* 4.62 ± 0.49 4.83 ± 0.42 
AZT and AZT/"-Interferon A/D, NTP TR 469 245 

TABLE K2 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Female (continued) 

Hematology (continued) 

Clinical Pathology Groups (continued) 

n 

Week 14 10 10 9 9 

Week 27 10 9 10 9 

Week 40 10 10 10 9 

Week 54 10 10 10 10 

Week 66 10 9 10 10 

Week 80 10 9 9 9 

Atypical lymphocytes (10 /μL) 3 

Week 14 0.00 ± 0.00b 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 27 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 40 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 54 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 66 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 80 0.00 ± 0.00 0.01 ± 0.01 0.00 ± 0.00 0.00 ± 0.00 

Monocytes (10 /μL) 3 

Week 14 0.06 ± 0.02b 0.08 ± 0.01 0.11 ± 0.03 0.07 ± 0.02 

Week 27 0.12 ± 0.04 0.04 ± 0.02 0.08 ± 0.03 0.08 ± 0.03 

Week 40 0.02 ± 0.01 0.01 ± 0.01 0.01 ± 0.01 0.03 ± 0.02 

Week 54 0.22 ± 0.03 0.11 ± 0.03 0.17 ± 0.04 0.17 ± 0.04 

Week 66 0.11 ± 0.03 0.08 ± 0.03 0.11 ± 0.03 0.12 ± 0.02 

Week 80 0.04 ± 0.02 0.12 ± 0.02* 0.05 ± 0.02 0.05 ± 0.03 

Eosinophils (10 /μL) 3 

Week 14 0.09 ± 0.04b 0.04 ± 0.02 0.08 ± 0.03 0.10 ± 0.04 

Week 27 0.07 ± 0.02 0.16 ± 0.06 0.14 ± 0.03 0.11 ± 0.02 

Week 40 0.11 ± 0.03 0.13 ± 0.06 0.11 ± 0.03 0.07 ± 0.01 

Week 54 0.25 ± 0.05 0.14 ± 0.03 0.18 ± 0.03 0.25 ± 0.05 

Week 66 0.10 ± 0.02 0.11 ± 0.03 0.12 ± 0.01 0.09 ± 0.02 

Week 80 0.10 ± 0.03 0.12 ± 0.02 0.09 ± 0.04 0.08 ± 0.03 

Core Groups 

n 8 8 8 8 

Hematocrit (%) 46.8 ± 2.9 40.4 ± 1.0** 41.7 ± 0.6** 38.2 ± 1.6** 

Hemoglobin (g/dL) 

Erythrocytes (10 /μL) 6 

Reticulocytes (10 /μL) 6 

Nucleated erythrocytes (10 /μL) 3 

15.6 ± 0.9 

9.88 ± 0.65 

0.24 ± 0.03 

0.00 ± 0.00 

13.3 ± 0.4** 

8.00 ± 0.19** 

0.19 ± 0.04 

0.00 ± 0.00 

13.9 ± 0.2** 

8.00 ± 0.12** 

0.19 ± 0.04 

0.00 ± 0.00 

12.6 ± 0.5** 

7.18 ± 0.31** 

0.16 ± 0.03 

0.00 ± 0.00 

Mean cell volume (fL) 47.5 ± 0.6 50.6 ± 0.6** 52.1 ± 0.3** 53.1 ± 0.5** 

Mean cell hemoglobin (pg) 15.8 ± 0.3 16.7 ± 0.2* 17.4 ± 0.1** 17.5 ± 0.1** 

Mean cell hemoglobin 

concentration (g/dL) 

Platelets (10 /μL) 3 

Leukocytes (10 /μL) 3 

Segmented neutrophils (10 /μL) 3 

Lymphocytes (10 /μL) 3 

Atypical lymphocytes (10 /μL) 3 

Monocytes (10 /μL) 3 

Eosinophils (10 /μL) 3 

33.4 ± 0.2 

1,193.3 ± 61.3 

5.85 ± 0.51 

1.52 ± 0.16 

3.90 ± 0.49 

0.09 ± 0.04 

0.23 ± 0.03 

0.10 ± 0.02 

33.0 ± 0.2 

1,125.4 ± 110.1 

4.73 ± 0.54 

1.39 ± 0.09 

2.95 ± 0.45 

0.09 ± 0.04 

0.18 ± 0.03 

0.11 ± 0.02 

33.4 ± 0.2 

1,230.6 ± 61.0 

5.11 ± 0.48 

1.28 ± 0.17 

3.44 ± 0.48 

0.09 ± 0.03 

0.18 ± 0.03 

0.09 ± 0.02 

33.0 ± 0.3 

1,266.3 ± 154.2 

4.94 ± 0.28 

1.76 ± 0.23 

2.73 ± 0.25 

0.04 ± 0.01 

0.28 ± 0.06 

0.10 ± 0.02 
246 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K2 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Female (continued) 

Bone Marrow Analyses 

Clinical Pathology Groups 

n 

Week 54 10 10 10 10 

Week 66 9 9 10 10 

Week 80 10 9 9 9 

Total femoral count (10 /femur) 6 

Week 54 25.5 ± 1.0 24.9 ± 1.0 24.3 ± 2.0 22.3 ± 1.3 

Week 66 28.1 ± 1.4 29.1 ± 1.5 27.7 ± 1.2 26.5 ± 0.8 

Week 80 28.2 ± 0.6 29.7 ± 1.6 25.6 ± 2.0 26.0 ± 1.2 

M:E ratio 

Week 54 1.45 ± 0.09 2.05 ± 0.13** 2.57 ± 0.25** 3.00 ± 0.17** 

Week 66 1.90 ± 0.29 1.44 ± 0.06 1.67 ± 0.25 1.63 ± 0.11 

Week 80 2.04 ± 0.17 2.28 ± 0.24 2.39 ± 0.35 2.82 ± 0.37 

Rubriblasts (10 )

6 

Week 54 0.72 ± 0.06 0.65 ± 0.08 0.38 ± 0.06** 0.42 ± 0.09** 

Week 66 0.56 ± 0.06 0.48 ± 0.04 0.47 ± 0.08 0.71 ± 0.10 

Week 80 0.33 ± 0.04 0.33 ± 0.04 0.32 ± 0.05 0.36 ± 0.04 

Prorubricytes (10 )

6 

Week 54 0.66 ± 0.05 0.48 ± 0.07 0.41 ± 0.06* 0.52 ± 0.06 

Week 66 0.43 ± 0.09 0.62 ± 0.12 0.51 ± 0.06 0.52 ± 0.08 

Week 80 1.03 ± 0.13 1.19 ± 0.18 1.32 ± 0.32 0.89 ± 0.13 

Rubricytes (10 )

6 

Week 54 3.46 ± 0.31 3.15 ± 0.17 2.67 ± 0.27* 2.16 ± 0.23** 

Week 66 4.67 ± 0.39 4.96 ± 0.31 4.65 ± 0.32 3.64 ± 0.24 

Week 80 3.49 ± 0.29 3.72 ± 0.25 3.34 ± 0.45 3.02 ± 0.33 

Metarubricytes (10 )

6 

Week 54 2.28 ± 0.16 1.19 ± 0.13** 1.06 ± 0.11** 0.75 ± 0.10** 

Week 66 1.27 ± 0.16 2.10 ± 0.14** 1.89 ± 0.17** 2.35 ± 0.23** 

Week 80 1.18 ± 0.10 1.16 ± 0.09 0.88 ± 0.16 0.63 ± 0.12** 

Myeloblasts (10 )

6 

Week 54 0.31 ± 0.06 0.29 ± 0.06 0.33 ± 0.07 0.22 ± 0.04 

Week 66 0.60 ± 0.14 0.41 ± 0.08 0.44 ± 0.06 0.62 ± 0.08 

Week 80 0.45 ± 0.08 0.46 ± 0.06 0.54 ± 0.09 0.53 ± 0.06 

Promyelocytes (10 )

6 

Week 54 0.42 ± 0.06 0.29 ± 0.04 0.25 ± 0.03* 0.18 ± 0.03** 

Week 66 0.25 ± 0.05 0.54 ± 0.12* 0.34 ± 0.06 0.39 ± 0.03 

Week 80 0.62 ± 0.07 0.71 ± 0.10 0.71 ± 0.12 0.82 ± 0.09 

Neutrophilic myelocytes (10 )

6 

Week 54 0.87 ± 0.11 1.14 ± 0.09 1.11 ± 0.11 1.09 ± 0.13 

Week 66 1.17 ± 0.20 0.83 ± 0.08 0.92 ± 0.12 1.02 ± 0.09 

Week 80 1.13 ± 0.15 1.27 ± 0.25 0.87 ± 0.14 1.19 ± 0.17 

Neutrophilic metamyelocytes (10 )

6 

Week 54 3.18 ± 0.16 3.17 ± 0.30 3.49 ± 0.37 3.22 ± 0.23 

Week 66 3.64 ± 0.25 3.93 ± 0.33 3.76 ± 0.53 3.62 ± 0.20 

Week 80 0.67 ± 0.11 0.98 ± 0.12 0.97 ± 0.24 1.03 ± 0.12 

Neutrophilic bands (10 )

6 

Week 54 0.26 ± 0.03 0.23 ± 0.03 0.27 ± 0.05 0.23 ± 0.03 

Week 66 0.40 ± 0.08 0.38 ± 0.07 0.30 ± 0.03 0.40 ± 0.06 

Week 80 1.00 ± 0.16 1.48 ± 0.29 0.93 ± 0.13 1.29 ± 0.27 
AZT and AZT/"-Interferon A/D, NTP TR 469 247 

TABLE K2 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Female (continued) 

Bone Marrow Analyses (continued) 

Clinical Pathology Groups (continued) 

n 

Week 54 10 10 10 10 

Week 66 9 9 10 10 

Week 80 10 9 9 9 

Neutrophilic segments (10 )

6 

Week 54 4.47 ± 0.32 5.24 ± 0.34 5.44 ± 0.50 5.57 ± 0.42 

Week 66 5.77 ± 0.68 5.17 ± 0.44 5.61 ± 0.52 4.65 ± 0.24 

Week 80 7.49 ± 0.54 8.35 ± 0.88 7.64 ± 1.14 7.18 ± 0.57 

Eosinophilic myelocytes (10 )

6 

Week 54 0.106 ± 0.023 0.079 ± 0.024 0.011 ± 0.008** 0.061 ± 0.017 

Week 66 0.048 ± 0.011 0.078 ± 0.016 0.016 ± 0.008 0.037 ± 0.008 

Week 80 0.098 ± 0.022 0.094 ± 0.042 0.061 ± 0.025 0.063 ± 0.018 

Eosinophilic metamyelocytes (10 )

6 

Week 54 0.21 ± 0.04 0.23 ± 0.06 0.21 ± 0.07 0.34 ± 0.07 

Week 66 0.26 ± 0.03 0.23 ± 0.02 0.24 ± 0.05 0.24 ± 0.04 

Week 80 0.075 ± 0.015 0.163 ± 0.060 0.119 ± 0.018 0.064 ± 0.012 

Eosinophilic bands (10 )

6 

Week 54 0.06 ± 0.02 0.05 ± 0.02 0.08 ± 0.02 0.11 ± 0.02 

Week 66 0.14 ± 0.03 0.18 ± 0.04 0.12 ± 0.03 0.24 ± 0.04 

Week 80 0.19 ± 0.03 0.27 ± 0.07 0.23 ± 0.06 0.23 ± 0.03 

Eosinophilic segments (10 )

6 

Week 54 0.14 ± 0.03 0.24 ± 0.04 0.28 ± 0.08 0.29 ± 0.05 

Week 66 0.17 ± 0.03 0.14 ± 0.04 0.17 ± 0.03 0.20 ± 0.03 

Week 80 0.12 ± 0.03 0.27 ± 0.05* 0.26 ± 0.07 0.23 ± 0.04 

Basophilic myelocytes (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 80 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic metamyelocytes (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 80 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic bands (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 80 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic segments (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 80 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Bone marrow lymphocytes (10 )

6 

Week 54 3.68 ± 0.60 4.21 ± 0.36 4.39 ± 0.55 3.20 ± 0.40 

Week 66 3.71 ± 0.42 3.40 ± 0.40 3.27 ± 0.22 3.51 ± 0.12 

Week 80 5.44 ± 0.47 4.19 ± 0.51 3.44 ± 0.32** 4.09 ± 0.27 

Bone marrow macrophages (10 )

6 

Week 54 0.08 ± 0.02 0.08 ± 0.02 0.09 ± 0.03 0.08 ± 0.03 

Week 66 0.15 ± 0.04 0.17 ± 0.05 0.24 ± 0.04 0.22 ± 0.03 

Week 80 0.21 ± 0.04 0.28 ± 0.07 0.17 ± 0.06 0.19 ± 0.04 
248 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K2 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Female (continued) 

Bone Marrow Analyses (continued) 

Clinical Pathology Groups (continued) 

n 

Week 54 10 10 10 10 

Week 66 9 9 10 10 

Week 80 10 9 9 9 

Bone marrow monocytes (10 )

6 

Week 54 0.000 ± 0.000 0.005 ± 0.005 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 80 0.18 ± 0.03 0.30 ± 0.06 0.26 ± 0.07 0.24 ± 0.05 

Megakaryo cells (10 )

6 

Week 54 0.041 ± 0.015 0.032 ± 0.012 0.028 ± 0.015 0.051 ± 0.016 

Week 66 0.13 ± 0.04 0.14 ± 0.04 0.10 ± 0.02 0.07 ± 0.02 

Week 80 0.11 ± 0.02 0.10 ± 0.02 0.10 ± 0.03 0.09 ± 0.02 

Plasma cells (10 )

6 

Week 54 0.18 ± 0.03 0.19 ± 0.05 0.14 ± 0.02 0.18 ± 0.03 

Week 66 0.13 ± 0.04 0.18 ± 0.04 0.18 ± 0.03 0.22 ± 0.04 

Week 80 0.25 ± 0.04 0.36 ± 0.07 0.20 ± 0.03 0.30 ± 0.07 

Mitotic figures (10 )

6 

Week 54 0.51 ± 0.06 0.38 ± 0.04 0.38 ± 0.06 0.27 ± 0.04** 

Week 66 0.23 ± 0.02 0.30 ± 0.05 0.25 ± 0.03 0.25 ± 0.05 

Week 80 0.08 ± 0.02 0.14 ± 0.04 0.07 ± 0.02 0.12 ± 0.02 

Fat cells (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 80 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Mast cells (10 )

6 

Week 54 0.006 ± 0.006 0.000 ± 0.000 0.009 ± 0.009 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.004 ± 0.004 0.005 ± 0.005 0.000 ± 0.000 

Week 80 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Smudge cells (10 )

6 

Week 54 3.82 ± 0.16 3.60 ± 0.26 3.25 ± 0.28 3.37 ± 0.23 

Week 66 4.34 ± 0.25 4.81 ± 0.49 4.23 ± 0.25 3.53 ± 0.29 

Week 80 4.05 ± 0.37 3.87 ± 0.30 3.17 ± 0.30 3.43 ± 0.27 

Osteoblasts (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 80 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Osteoclasts (10 )

6 

Week 54 0.016 ± 0.008 0.005 ± 0.005 0.017 ± 0.009 0.000 ± 0.000 

Week 66 0.014 ± 0.010 0.019 ± 0.013 0.023 ± 0.009 0.031 ± 0.011 

Week 80 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Other bone marrow cells (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 80 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Neutrophilic hypersegments (10 )

6 

Week 54 0.30 ± 0.09 0.50 ± 0.11 0.45 ± 0.09 0.46 ± 0.08 

Week 66 0.08 ± 0.04 0.09 ± 0.04 0.12 ± 0.04 0.27 ± 0.05** 

Week 80 0.05 ± 0.02 0.13 ± 0.07 0.10 ± 0.05 0.15 ± 0.05 
AZT and AZT/"-Interferon A/D, NTP TR 469 249 

TABLE K2 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Female (continued) 

Bone Marrow Analyses (continued) 

Core Groups 

n 9 9 8 8 

Total femoral count (10 /femur) 6 19.3 ± 0.9 24.8 ± 2.1 24.1 ± 2.7 21.7 ± 1.3 

M:E ratio 2.01 ± 0.22 2.38 ± 0.29 3.98 ± 1.14 5.63 ± 1.23* 

Rubriblasts (10 )

6 

Prorubricytes (10 )

6 

Rubricytes (10 )

6 

Metarubricytes (10 )

6 

Myeloblasts (10 )

6 

Promyelocytes (10 )

6 

Neutrophilic myelocytes (10 )

6 

Neutrophilic metamyelocytes (10 )

6 

Neutrophilic bands (10 )

6 

Neutrophilic segments (10 )

6 

Eosinophilic myelocytes (10 )

6 

Eosinophilic metamyelocytes (10 )

6 

Eosinophilic bands (10 )

6 

Eosinophilic segments (10 )

6 

Basophilic myelocytes (10 )

6 

Basophilic metamyelocytes (10 )

6 

Basophilic bands (10 )

6 

Basophilic segments (10 )

6 

Bone marrow lymphocytes (10 )

6 

Bone marrow macrophages (10 )

6 

Bone marrow monocytes (10 )

6 

Megakaryo cells (10 )

6 

Plasma cells (10 )

6 

Mitotic figures (10 )

6 

Fat cells (10 )

6 

Mast cells (10 )

6 

Smudge cells (10 )

6 

Osteoblasts (10 )

6 

Osteoclasts (10 )

6 

Other bone marrow cells (10 )

6 

Neutrophilic hypersegments (10 )

6 

0.38 ± 0.03 

0.91 ± 0.14 

2.64 ± 0.29 

1.10 ± 0.14 

0.28 ± 0.03 

0.29 ± 0.06 

0.61 ± 0.07 

0.77 ± 0.12 

2.97 ± 0.40 

4.08 ± 0.26 

0.026 ± 0.007 

0.071 ± 0.037 

0.17 ± 0.02 

0.14 ± 0.03 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

2.77 ± 0.29 

0.11 ± 0.02 

0.18 ± 0.04 

0.06 ± 0.02 

0.28 ± 0.04 

0.14 ± 0.02 

0.000 ± 0.000 

0.000 ± 0.000 

1.36 ± 0.29 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.06 ± 0.03 

0.39 ± 0.07 

0.90 ± 0.21 

3.20 ± 0.47 

1.17 ± 0.22 

0.39 ± 0.07 

0.60 ± 0.08* 

0.74 ± 0.07 

1.15 ± 0.24 

2.95 ± 0.62 

5.51 ± 0.47* 

0.069 ± 0.018 

0.039 ± 0.011 

0.29 ± 0.06 

0.20 ± 0.05 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

3.87 ± 0.57 

0.25 ± 0.06 

0.33 ± 0.07 

0.09 ± 0.03 

0.48 ± 0.08 

0.18 ± 0.04 

0.000 ± 0.000 

0.000 ± 0.000 

1.72 ± 0.31 

0.201 ± 0.201 

0.014 ± 0.010 

0.000 ± 0.000 

0.14 ± 0.04 

0.38 ± 0.06 

0.86 ± 0.16 

2.17 ± 0.34 

1.14 ± 0.33 

0.54 ± 0.14 

0.51 ± 0.12 

0.97 ± 0.12 

0.92 ± 0.24 

2.61 ± 0.39 

7.72 ± 1.06** 

0.009 ± 0.009 

0.050 ± 0.017 

0.21 ± 0.06 

0.19 ± 0.05 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

3.04 ± 0.46 

0.09 ± 0.02 

0.31 ± 0.06 

0.09 ± 0.02 

0.57 ± 0.17 

0.11 ± 0.03 

0.000 ± 0.000 

0.000 ± 0.000 

1.65 ± 0.19 

0.000 ± 0.000 

0.004 ± 0.004 

0.000 ± 0.000 

0.32 ± 0.06** 

0.36 ± 0.07 

0.68 ± 0.17 

1.83 ± 0.52 

0.49 ± 0.15 

0.34 ± 0.04 

0.48 ± 0.17 

0.92 ± 0.20 

0.84 ± 0.19 

2.82 ± 0.66 

6.84 ± 0.73** 

0.054 ± 0.019 

0.019 ± 0.007 

0.20 ± 0.05 

0.21 ± 0.05 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

2.54 ± 0.29 

0.15 ± 0.03 

0.22 ± 0.05 

0.09 ± 0.02 

0.52 ± 0.07* 

0.13 ± 0.04 

0.000 ± 0.000 

0.000 ± 0.000 

2.02 ± 0.27 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.22 ± 0.06** 

* Significantly different (P#0.05) from the control group by Dunn’s or Shirley’s test 

** P#0.01 a Mean ± standard error. Statistical tests were performed on unrounded data. b n=9
 

n=8
 c 
250 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K3 

Hematology and Bone Marrow Data for Mice in the 2-Year Subcutaneous Study of "-Interferon A/Da 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Male 

Hematology 

Clinical Pathology Groups 

n 

Week 14 8 10 9 10 

Week 27 10 10 10 10 

Week 40 10 10 9 9 

Week 54 9 10 10 10 

Week 66 10 10 10 10 

Week 79 10 9 8 9 

Hematocrit (%) 

Week 14 45.2 ± 0.3 46.3 ± 0.6 45.7 ± 0.3 45.5 ± 0.3 

Week 27 46.1 ± 0.4 44.5 ± 0.7 46.3 ± 0.5 47.0 ± 0.8 

Week 40 42.0 ± 0.6 43.1 ± 0.4 43.3 ± 0.4 42.2 ± 0.4 

Week 54 43.3 ± 0.5 43.7 ± 0.7 45.0 ± 0.6 43.0 ± 0.9 

Week 66 46.2 ± 1.4 43.6 ± 1.0 45.6 ± 1.6 43.1 ± 0.9 

Week 79 44.5 ± 1.3 44.6 ± 1.4 43.6 ± 0.7 43.3 ± 1.3 

Hemoglobin (g/dL) 

Week 14 15.1 ± 0.1 15.3 ± 0.2 15.1 ± 0.1 15.1 ± 0.1 

Week 27 15.5 ± 0.1 15.0 ± 0.3 15.4 ± 0.1 15.5 ± 0.3 

Week 40 14.0 ± 0.2 14.4 ± 0.1 14.5 ± 0.2 14.1 ± 0.2 

Week 54 14.4 ± 0.2 14.6 ± 0.3 15.0 ± 0.2 14.2 ± 0.3 

Week 66 15.5 ± 0.5 14.7 ± 0.4 15.3 ± 0.5 14.2 ± 0.3 

Week 79 14.6 ± 0.4 14.8 ± 0.5 14.5 ± 0.3 14.3 ± 0.5 

Erythrocytes (10 /μL) 6 

Week 14 9.63 ± 0.07 9.79 ± 0.11 9.65 ± 0.08 9.70 ± 0.06 

Week 27 10.12 ± 0.08 9.82 ± 0.14 10.18 ± 0.10 10.24 ± 0.16 

Week 40 9.04 ± 0.10 9.27 ± 0.09 9.17 ± 0.11 9.11 ± 0.10 

Week 54 9.41 ± 0.08 9.42 ± 0.15 9.66 ± 0.11 9.25 ± 0.17 

Week 66 9.90 ± 0.53 9.22 ± 0.20 9.52 ± 0.44 9.29 ± 0.16 

Week 79 9.57 ± 0.44 9.46 ± 0.44 8.92 ± 0.12 9.29 ± 0.49 

Reticulocytes (10 /μL) 6 

Week 14 0.18 ± 0.03 0.18 ± 0.02 0.17 ± 0.02 0.19 ± 0.01 

Week 27 0.23 ± 0.01 0.20 ± 0.02 0.17 ± 0.01* 0.19 ± 0.01 

Week 40 0.27 ± 0.02b 0.27 ± 0.02 0.22 ± 0.01 0.21 ± 0.01* 

Week 54 0.25 ± 0.02 0.22 ± 0.02 0.22 ± 0.02 0.23 ± 0.02 

Week 66 0.18 ± 0.02 0.14 ± 0.01 0.15 ± 0.01 0.19 ± 0.01 

Week 79 0.12 ± 0.01 0.12 ± 0.01 0.10 ± 0.01 0.12 ± 0.02 

Nucleated erythrocytes (10 /μL) 3 

Week 14 0.02 ± 0.01 0.00 ± 0.00 0.01 ± 0.01 0.00 ± 0.00 

Week 27 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 40 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 54 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 66 0.00 ± 0.00 0.00 ± 0.00 0.01 ± 0.01 0.00 ± 0.00 

Week 79 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Mean cell volume (fL) 

Week 14 46.9 ± 0.2 47.3 ± 0.2 47.4 ± 0.3 47.0 ± 0.3 

Week 27 45.6 ± 0.3 45.3 ± 0.3 45.4 ± 0.2 45.9 ± 0.3 

Week 40 46.4 ± 0.5 46.5 ± 0.3 47.3 ± 0.4 46.3 ± 0.5 

Week 54 46.0 ± 0.3 46.4 ± 0.3 46.6 ± 0.3 46.4 ± 0.4 

Week 66 47.1 ± 1.1 47.3 ± 0.7 48.1 ± 0.5 46.4 ± 0.8 

Week 79 46.9 ± 1.0 47.4 ± 0.8 48.9 ± 0.8 47.0 ± 1.1 
AZT and AZT/"-Interferon A/D, NTP TR 469 251 

TABLE K3 

Hematology and Bone Marrow Data for Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Male (continued) 

Hematology (continued) 

Clinical Pathology Groups (continued) 

n 

Week 14 8 10 9 10 

Week 27 10 10 10 10 

Week 40 10 10 9 9 

Week 54 9 10 10 10 

Week 66 10 10 10 10 

Week 79 10 9 8 9 

Mean cell hemoglobin (pg) 

Week 14 15.7 ± 0.1 15.6 ± 0.1 15.6 ± 0.1 15.5 ± 0.1 

Week 27 15.3 ± 0.1 15.2 ± 0.1 15.2 ± 0.1 15.2 ± 0.1 

Week 40 15.4 ± 0.1 15.5 ± 0.1 15.8 ± 0.1 15.4 ± 0.1 

Week 54 15.3 ± 0.2 15.4 ± 0.1 15.5 ± 0.1 15.3 ± 0.1 

Week 66 15.8 ± 0.4 15.9 ± 0.3 16.2 ± 0.2 15.3 ± 0.3 

Week 79 15.4 ± 0.3 15.7 ± 0.3 16.3 ± 0.3 15.5 ± 0.4 

Mean cell hemoglobin concentration (g/dL) 

Week 14 33.4 ± 0.2 33.0 ± 0.1 32.9 ± 0.1 33.1 ± 0.1 

Week 27 33.5 ± 0.1 33.6 ± 0.2 33.4 ± 0.2 33.1 ± 0.2 

Week 40 33.2 ± 0.2 33.3 ± 0.2 33.4 ± 0.2 33.4 ± 0.2 

Week 54 33.2 ± 0.3 33.2 ± 0.3 33.3 ± 0.2 32.9 ± 0.2 

Week 66 33.6 ± 0.3 33.7 ± 0.2 33.6 ± 0.2 32.9 ± 0.2 

Week 79 32.9 ± 0.2 33.2 ± 0.2 33.3 ± 0.2 33.1 ± 0.2 

Platelets (10 /μL) 3 

Week 14 1,334.1 ± 40.0 1,229.4 ± 38.5 1,356.3 ± 34.5 1,369.4 ± 45.4 

Week 27 1,050.6 ± 52.2 1,205.8 ± 72.0 1,115.1 ± 37.7 1,120.2 ± 60.5 

Week 40 1,308.2 ± 44.2 1,350.9 ± 47.0 1,435.7 ± 30.5 1,528.4 ± 62.7* 

Week 54 1,376.8 ± 44.7 1,235.3 ± 58.6 1,258.4 ± 37.5 1,376.6 ± 170.2 

Week 66 1,665.0 ± 170.7 1,348.2 ± 83.7 1,295.0 ± 73.4 1,484.2 ± 72.2 

Week 79 

Leukocytes (10 /μL) 3 1,669.6 ± 103.6 1,633.0 ± 69.7 1,556.0 ± 109.6 1,765.4 ± 100.5 

Week 14 8.21 ± 0.63 8.18 ± 0.45 7.38 ± 0.49 7.72 ± 0.48 

Week 27 7.95 ± 0.51 8.60 ± 0.50 8.31 ± 0.41 7.90 ± 0.40 

Week 40 8.35 ± 0.43 8.04 ± 0.64 7.00 ± 0.38 8.67 ± 0.57 

Week 54 8.14 ± 0.92 7.24 ± 0.58 6.41 ± 0.80 6.71 ± 0.99 

Week 66 10.29 ± 0.84 10.73 ± 1.15 8.55 ± 0.83 11.54 ± 1.03 

Week 79 11.66 ± 0.84 12.12 ± 1.19 9.06 ± 0.64 11.75 ± 0.95 

Segmented neutrophils (10 /μL) 3 

Week 14 1.83 ± 0.27 1.65 ± 0.18 1.56 ± 0.23 1.97 ± 0.12 

Week 27 1.33 ± 0.20 1.45 ± 0.17 1.69 ± 0.18 1.49 ± 0.12 

Week 40 2.08 ± 0.33 1.89 ± 0.24 1.46 ± 0.17 1.91 ± 0.20 

Week 54 1.69 ± 0.42 1.50 ± 0.21 1.13 ± 0.20 1.11 ± 0.13 

Week 66 2.18 ± 0.29 2.35 ± 0.50 1.99 ± 0.40 2.12 ± 0.21 

Week 79 2.50 ± 0.31 2.59 ± 0.35 2.91 ± 0.68 2.72 ± 0.38 

Lymphocytes (10 /μL) 3 

Week 14 6.18 ± 0.37 6.29 ± 0.36 5.62 ± 0.32 5.46 ± 0.43 

Week 27 6.40 ± 0.29 6.81 ± 0.39 6.35 ± 0.33 6.12 ± 0.36 

Week 40 6.18 ± 0.24 6.06 ± 0.46 5.39 ± 0.30 6.56 ± 0.39 

Week 54 6.16 ± 0.62 5.50 ± 0.43 5.11 ± 0.59 5.39 ± 0.88 

Week 66 7.61 ± 0.60 7.90 ± 0.80 6.13 ± 0.56 8.76 ± 0.79 

Week 79 9.03 ± 0.65 9.38 ± 0.91 6.06 ± 0.17** 8.88 ± 0.68 
252 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K3 

Hematology and Bone Marrow Data for Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Male (continued) 

Hematology (continued) 

Clinical Pathology Groups (continued) 

n 

Week 14 8 10 9 10 

Week 27 10 10 10 10 

Week 40 10 10 9 9 

Week 54 9 10 10 10 

Week 66 10 10 10 10 

Week 79 10 9 8 9 

Atypical lymphocytes (10 /μL) 3 

Week 14 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 27 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 40 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 54 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 66 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 79 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Monocytes (10 /μL) 3 

Week 14 0.06 ± 0.03 0.03 ± 0.01 0.01 ± 0.01 0.07 ± 0.03 

Week 27 0.05 ± 0.02 0.10 ± 0.05 0.10 ± 0.04 0.10 ± 0.05 

Week 40 0.03 ± 0.02 0.03 ± 0.03 0.02 ± 0.01 0.02 ± 0.02 

Week 54 0.15 ± 0.07 0.07 ± 0.03 0.07 ± 0.02 0.11 ± 0.04 

Week 66 0.39 ± 0.08 0.33 ± 0.07 0.29 ± 0.03 0.50 ± 0.08 

Week 79 0.10 ± 0.04 0.06 ± 0.02 0.06 ± 0.04 0.10 ± 0.03 

Eosinophils (10 /μL) 3 

Week 14 0.14 ± 0.04 0.21 ± 0.05 0.18 ± 0.06 0.22 ± 0.04 

Week 27 0.17 ± 0.06 0.23 ± 0.05 0.17 ± 0.04 0.19 ± 0.06 

Week 40 0.07 ± 0.03 0.07 ± 0.03 0.13 ± 0.06 0.17 ± 0.06 

Week 54 0.13 ± 0.03 0.17 ± 0.04 0.10 ± 0.03 0.11 ± 0.03 

Week 66 0.11 ± 0.03 0.15 ± 0.05 0.13 ± 0.02 0.15 ± 0.03 

Week 79 0.05 ± 0.03 0.08 ± 0.05 0.02 ± 0.02 0.04 ± 0.02 

Core Groups 

n 10 10 10 10 

Hematocrit (%) 37.9 ± 1.3 39.3 ± 2.4 42.1 ± 2.4 39.8 ± 1.8 

Hemoglobin (g/dL) 

Erythrocytes (10 /μL) 6 

Reticulocytes (10 /μL) 6 

Nucleated erythrocytes (10 /μL) 3 

12.6 ± 0.5 

8.10 ± 0.42 

0.30 ± 0.04 

0.00 ± 0.00 

13.5 ± 0.8 

8.83 ± 0.5 

0.24 ± 0.0 

0.00 ± 0.0 

14.3 ± 0.9 

9.28 ± 0.62 

0.38 ± 0.07 

0.00 ± 0.00 

13.7 ± 0.6 

8.91 ± 0.395 

0.24 ± 0.043 

0.00 ± 0.00 

Mean cell volume (fL) 47.3 ± 1.4 44.6 ± 0.6 45.8 ± 1.3 44.7 ± 0.7 

Mean cell hemoglobin (pg) 15.8 ± 0.4 15.3 ± 0.2 15.5 ± 0.3 15.4 ± 0.2 

Mean cell hemoglobin 

concentration (g/dL) 

Platelets (10 /μL) 3 

Leukocytes (10 /μL) 3 

Segmented neutrophils (10 /μL) 3 

Lymphocytes (10 /μL) 3 

Atypical lymphocytes (10 /μL) 3 

Monocytes (10 /μL) 3 

Eosinophils (10 /μL) 3 

33.4 ± 0.3 

1,915.1 ± 231.1 

9.15 ± 0.89 

2.83 ± 0.47 

5.49 ± 0.67 

0.12 ± 0.04 

0.58 ± 0.10 

0.09 ± 0.01 

34.2 ± 0.2 

1,819.3 ± 100.2 

9.75 ± 0.73 

3.96 ± 0.58 

4.99 ± 0.44 

0.18 ± 0.12 

0.51 ± 0.09 

0.08 ± 0.02 

34.0 ± 0.4 

1,937.4 ± 152.8 

9.11 ± 0.71 

3.21 ± 0.45 

5.11 ± 0.63 

0.12 ± 0.05 

0.52 ± 0.08 

0.09 ± 0.02 

34.3 ± 0.1 

1,579.1 ± 104.3 

8.93 ± 0.74 

3.29 ± 0.51 

4.98 ± 0.42 

0.03 ± 0.02 

0.48 ± 0.05 

0.09 ± 0.03 
AZT and AZT/"-Interferon A/D, NTP TR 469 253 

TABLE K3 

Hematology and Bone Marrow Data for Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Male (continued) 

Bone Marrow Analyses 

Clinical Pathology Groups 

n 

Week 54 9 9 9 10 

Week 66 10 9 10 10 

Week 79 10 9 8 9 

Total femoral count (10 /femur) 6 

Week 54 30.6 ± 1.4 28.1 ± 1.5 29.4 ± 1.0 27.3 ± 1.2 

Week 66 34.2 ± 1.4 33.9 ± 1.4 30.9 ± 1.9 34.7 ± 1.5 

Week 79 38.7 ± 1.6 37.5 ± 1.9 37.2 ± 1.4 36.5 ± 1.6 

M:E ratio 

Week 54 2.84 ± 0.22 2.93 ± 0.19c 2.91 ± 0.52 2.88 ± 0.34 

Week 66 3.61 ± 0.24 3.26 ± 0.33 4.55 ± 0.84 3.13 ± 0.36 

Week 79 2.87 ± 0.25 3.14 ± 0.23 4.35 ± 0.71 3.32 ± 0.26 

Rubriblasts (10 )

6 

Week 54 0.38 ± 0.06 0.36 ± 0.07 0.41 ± 0.07 0.34 ± 0.04 

Week 66 0.14 ± 0.03 0.25 ± 0.05 0.12 ± 0.03 0.22 ± 0.03 

Week 79 0.49 ± 0.04 0.38 ± 0.04 0.40 ± 0.04 0.34 ± 0.03* 

Prorubricytes (10 )

6 

Week 54 0.22 ± 0.04 0.20 ± 0.03 0.20 ± 0.03 0.14 ± 0.02 

Week 66 0.16 ± 0.04 0.13 ± 0.02 0.12 ± 0.03 0.20 ± 0.03 

Week 79 0.61 ± 0.10 0.78 ± 0.10 0.56 ± 0.09 0.72 ± 0.15 

Rubricytes (10 )

6 

Week 54 3.07 ± 0.19 2.77 ± 0.18 3.48 ± 0.27 3.10 ± 0.40 

Week 66 3.38 ± 0.30 3.39 ± 0.25 2.91 ± 0.40 3.54 ± 0.40 

Week 79 4.56 ± 0.30 3.35 ± 0.37 3.54 ± 0.51 3.33 ± 0.28 

Metarubricytes (10 )

6 

Week 54 1.91 ± 0.21 1.60 ± 0.18 1.72 ± 0.28 1.75 ± 0.32 

Week 66 1.35 ± 0.17 1.68 ± 0.16 1.21 ± 0.15 1.99 ± 0.15* 

Week 79 1.53 ± 0.20 1.45 ± 0.23 0.88 ± 0.17 1.23 ± 0.18 

Myeloblasts (10 )

6 

Week 54 0.53 ± 0.07 0.59 ± 0.07 0.55 ± 0.07 0.59 ± 0.13 

Week 66 0.25 ± 0.03 0.35 ± 0.04 0.39 ± 0.06 0.41 ± 0.05* 

Week 79 0.72 ± 0.09 0.64 ± 0.10 0.63 ± 0.09 0.67 ± 0.09 

Promyelocytes (10 )

6 

Week 54 0.44 ± 0.09 0.46 ± 0.07 0.40 ± 0.05 0.34 ± 0.03 

Week 66 0.34 ± 0.05 0.41 ± 0.11 0.34 ± 0.04 0.31 ± 0.04 

Week 79 0.92 ± 0.14 0.87 ± 0.18 0.93 ± 0.14 0.75 ± 0.08 

Neutrophilic myelocytes (10 )

6 

Week 54 0.57 ± 0.05 0.75 ± 0.13 0.63 ± 0.08 0.67 ± 0.05 

Week 66 0.76 ± 0.08 0.95 ± 0.35 0.73 ± 0.08 0.68 ± 0.06 

Week 79 1.22 ± 0.13 1.26 ± 0.23 1.15 ± 0.10 1.29 ± 0.30 

Neutrophilic metamyelocytes (10 )

6 

Week 54 2.97 ± 0.25 3.14 ± 0.32 3.39 ± 0.25 3.31 ± 0.31 

Week 66 3.55 ± 0.19 3.22 ± 0.32 3.66 ± 0.22 3.68 ± 0.23 

Week 79 3.16 ± 0.28 1.23 ± 0.30** 3.52 ± 0.65 1.99 ± 0.46* 

Neutrophilic bands (10 )

6 

Week 54 0.52 ± 0.07 0.43 ± 0.06 0.52 ± 0.13 0.36 ± 0.07 

Week 66 0.68 ± 0.09 0.49 ± 0.08 0.54 ± 0.12 0.31 ± 0.07* 

Week 79 2.50 ± 0.17 3.17 ± 0.37 1.67 ± 0.23 2.03 ± 0.42 
254 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K3 

Hematology and Bone Marrow Data for Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Male (continued) 

Bone Marrow Analyses (continued) 

Clinical Pathology Groups (continued) 

n 

Week 54 9 9 9 10 

Week 66 10 9 10 10 

Week 79 10 9 8 9 

Neutrophilic segments (10 )

6 

Week 54 9.72 ± 0.83 8.19 ± 0.65 8.66 ± 0.61 7.64 ± 0.44 

Week 66 11.15 ± 0.64 10.72 ± 0.82 10.25 ± 0.90 10.74 ± 0.43 

Week 79 10.38 ± 0.64 10.29 ± 0.88 11.88 ± 0.83 10.69 ± 0.84 

Eosinophilic myelocytes (10 )

6 

Week 54 0.120 ± 0.037 0.051 ± 0.016 0.046 ± 0.019 0.037 ± 0.013 

Week 66 0.069 ± 0.025 0.073 ± 0.014 0.039 ± 0.014 0.083 ± 0.025 

Week 79 0.102 ± 0.023 0.014 ± 0.014** 0.035 ± 0.013 0.012 ± 0.008** 

Eosinophilic metamyelocytes (10 )

6 

Week 54 0.00 ± 0.00 0.03 ± 0.02 0.00 ± 0.00 0.02 ± 0.01 

Week 66 0.12 ± 0.02 0.07 ± 0.02 0.06 ± 0.02 0.09 ± 0.02 

Week 79 0.09 ± 0.02 0.06 ± 0.03 0.03 ± 0.01 0.09 ± 0.04 

Eosinophilic bands (10 )

6 

Week 54 0.03 ± 0.01 0.01 ± 0.01 0.04 ± 0.02 0.01 ± 0.01 

Week 66 0.03 ± 0.01 0.07 ± 0.02 0.03 ± 0.01 0.08 ± 0.02 

Week 79 0.17 ± 0.04 0.24 ± 0.09 0.17 ± 0.05 0.10 ± 0.03 

Eosinophilic segments (10 )

6 

Week 54 0.57 ± 0.08 0.40 ± 0.03 0.59 ± 0.07 0.55 ± 0.08 

Week 66 0.62 ± 0.07 0.55 ± 0.11 0.43 ± 0.06 0.68 ± 0.08 

Week 79 0.28 ± 0.04 0.23 ± 0.05 0.42 ± 0.07 0.33 ± 0.05 

Basophilic myelocytes (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic metamyelocytes (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic bands (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic segments (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.007 ± 0.007 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Bone marrow lymphocytes (10 )

6 

Week 54 3.94 ± 0.29 4.10 ± 0.38 3.84 ± 0.33 3.52 ± 0.39 

Week 66 5.23 ± 0.21 5.23 ± 0.54 4.53 ± 0.56 5.32 ± 0.56 

Week 79 7.04 ± 0.58 8.08 ± 1.04 5.08 ± 0.47 6.01 ± 0.66 

Bone marrow macrophages (10 )

6 

Week 54 0.12 ± 0.04 0.07 ± 0.03 0.10 ± 0.03 0.03 ± 0.01 

Week 66 0.12 ± 0.03 0.16 ± 0.04 0.08 ± 0.02 0.12 ± 0.04 

Week 79 0.19 ± 0.04 0.21 ± 0.05 0.14 ± 0.02 0.12 ± 0.01 
AZT and AZT/"-Interferon A/D, NTP TR 469 255 

TABLE K3 

Hematology and Bone Marrow Data for Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Male (continued) 

Bone Marrow Analyses (continued) 

Clinical Pathology Groups (continued) 

n 

Week 54 9 9 9 10 

Week 66 10 9 10 10 

Week 79 10 9 8 9 

Bone marrow monocytes (10 )

6 

Week 54 0.33 ± 0.12 0.31 ± 0.10 0.16 ± 0.05 0.24 ± 0.05 

Week 66 0.13 ± 0.04 0.15 ± 0.06 0.09 ± 0.03 0.08 ± 0.02 

Week 79 0.67 ± 0.10 0.31 ± 0.04** 0.53 ± 0.05 0.42 ± 0.09 

Megakaryo cells (10 )

6 

Week 54 0.09 ± 0.02 0.09 ± 0.02 0.05 ± 0.02 0.11 ± 0.04 

Week 66 0.11 ± 0.03 0.09 ± 0.02 0.12 ± 0.02 0.16 ± 0.02 

Week 79 0.09 ± 0.02 0.22 ± 0.03* 0.09 ± 0.02 0.12 ± 0.03 

Plasma cells (10 )

6 

Week 54 0.26 ± 0.03 0.18 ± 0.03 0.19 ± 0.07 0.16 ± 0.02 

Week 66 0.21 ± 0.04 0.19 ± 0.03 0.22 ± 0.04 0.21 ± 0.04 

Week 79 0.33 ± 0.10 0.33 ± 0.09 0.19 ± 0.04 0.51 ± 0.16 

Mitotic figures (10 )

6 

Week 54 0.46 ± 0.09 0.40 ± 0.06 0.49 ± 0.08 0.30 ± 0.05 

Week 66 0.34 ± 0.07 0.33 ± 0.07 0.27 ± 0.05 0.26 ± 0.03 

Week 79 0.06 ± 0.01 0.25 ± 0.05** 0.08 ± 0.02 0.22 ± 0.04** 

Fat cells (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Mast cells (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Smudge cells (10 )

6 

Week 54 4.32 ± 0.25 3.94 ± 0.26 3.98 ± 0.20 4.03 ± 0.18 

Week 66 5.45 ± 0.28 5.40 ± 0.34 4.78 ± 0.38 5.50 ± 0.31 

Week 79 3.59 ± 0.23 4.15 ± 0.22 5.32 ± 0.22** 5.46 ± 0.41** 

Osteoblasts (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Osteoclasts (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.007 ± 0.007 

Other bone marrow cells (10 )

6 

Week 54 0.019 ± 0.014 0.000 ± 0.000 0.008 ± 0.008 0.012 ± 0.008 

Week 66 0.016 ± 0.016 0.007 ± 0.007 0.000 ± 0.000 0.012 ± 0.012 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Neutrophilic hypersegments (10 )

6 

Week 54 0.01 ± 0.01 0.06 ± 0.02* 0.00 ± 0.00 0.08 ± 0.02** 

Week 66 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 79 0.05 ± 0.03 0.19 ± 0.05* 0.15 ± 0.07 0.15 ± 0.06 
256 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K3 

Hematology and Bone Marrow Data for Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Male (continued) 

Bone Marrow Analyses (continued) 

Core Groups 

n 10 10 10 10 

Total femoral count (10 /femur) 6 28.0 ± 0.7 29.3 ± 2.8 28.1 ± 1.3 29.6 ± 1.2 

M:E ratio 1.59 ± 0.18 2.45 ± 0.34 2.03 ± 0.26 1.92 ± 0.11 

Rubriblasts (10 )

6 

Prorubricytes (10 )

6 

Rubricytes (10 )

6 

Metarubricytes (10 )

6 

Myeloblasts (10 )

6 

Promyelocytes (10 )

6 

Neutrophilic myelocytes (10 )

6 

Neutrophilic metamyelocytes (10 )

6 

Neutrophilic bands (10 )

6 

Neutrophilic segments (10 )

6 

Eosinophilic myelocytes (10 )

6 

Eosinophilic metamyelocytes (10 )

6 

Eosinophilic bands (10 )

6 

Eosinophilic segments (10 )

6 

Basophilic myelocytes (10 )

6 

Basophilic metamyelocytes (10 )

6 

Basophilic bands (10 )

6 

Basophilic segments (10 )

6 

Bone marrow lymphocytes (10 )

6 

Bone marrow macrophages (10 )

6 

Bone marrow monocytes (10 )

6 

Megakaryo cells (10 )

6 

Plasma cells (10 )

6 

Mitotic figures (10 )

6 

Fat cells (10 )

6 

Mast cells (10 )

6 

Smudge cells (10 )

6 

Osteoblasts (10 )

6 

Osteoclasts (10 )

6 

Other bone marrow cells (10 )

6 

Neutrophilic hypersegments (10 )

6 

0.41 ± 0.06 

0.93 ± 0.14 

6.14 ± 0.41 

1.80 ± 0.41 

0.42 ± 0.06 

0.47 ± 0.08 

1.45 ± 0.19 

1.02 ± 0.17 

3.32 ± 0.40 

6.70 ± 0.61 

0.010 ± 0.010 

0.032 ± 0.016 

0.12 ± 0.04 

0.18 ± 0.02 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

2.10 ± 0.18 

0.28 ± 0.08 

0.27 ± 0.06 

0.12 ± 0.02 

0.41 ± 0.15 

0.24 ± 0.05 

0.000 ± 0.000 

0.000 ± 0.000 

1.59 ± 0.21 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.05 ± 0.03 

0.31 ± 0.08 

1.00 ± 0.14 

4.84 ± 0.96 

1.66 ± 0.34 

0.44 ± 0.07 

0.57 ± 0.09 

1.17 ± 0.20 

1.21 ± 0.25 

3.94 ± 0.75 

8.73 ± 0.77 

0.070 ± 0.017** 

0.085 ± 0.033 

0.16 ± 0.03 

0.19 ± 0.05 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

1.93 ± 0.27 

0.21 ± 0.04 

0.35 ± 0.11 

0.13 ± 0.02 

0.40 ± 0.10 

0.21 ± 0.06 

0.000 ± 0.000 

0.000 ± 0.000 

1.67 ± 0.30 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.03 ± 0.02 

0.35 ± 0.05 

1.12 ± 0.22 

5.76 ± 0.70 

1.18 ± 0.22 

0.46 ± 0.06 

0.53 ± 0.09 

0.73 ± 0.13* 

0.84 ± 0.14 

3.21 ± 0.46 

9.11 ± 0.65* 

0.009 ± 0.009 

0.034 ± 0.018 

0.11 ± 0.04 

0.16 ± 0.06 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

1.64 ± 0.35 

0.18 ± 0.05 

0.26 ± 0.05 

0.08 ± 0.02 

0.45 ± 0.09 

0.21 ± 0.04 

0.000 ± 0.000 

0.000 ± 0.000 

1.67 ± 0.28 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.05 ± 0.04 

0.40 ± 0.05 

0.73 ± 0.14 

5.67 ± 0.59 

1.59 ± 0.20 

0.55 ± 0.08 

0.50 ± 0.11 

1.34 ± 0.21 

1.19 ± 0.16 

3.93 ± 0.65 

7.73 ± 0.48 

0.011 ± 0.011 

0.013 ± 0.009 

0.13 ± 0.02 

0.12 ± 0.03 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

2.58 ± 0.49 

0.21 ± 0.07 

0.31 ± 0.08 

0.14 ± 0.03 

0.62 ± 0.14 

0.24 ± 0.05 

0.000 ± 0.000 

0.000 ± 0.000 

1.63 ± 0.18 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.10 ± 0.04 
AZT and AZT/"-Interferon A/D, NTP TR 469 257 

TABLE K3 

Hematology and Bone Marrow Data for Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Female 

Hematology 

Clinical Pathology Groups 

n 

Week 14 10 9 10 9 

Week 27 10 10 10 10 

Week 40 9 10 10 9 

Week 54 10 10 10 9 

Week 66 10 10 9 10 

Week 79 9 9 10 7 

Hematocrit (%) 

Week 14 45.9 ± 0.3 45.8 ± 0.4 45.4 ± 0.6 45.2 ± 0.5 

Week 27 45.6 ± 0.1 45.7 ± 0.4 45.4 ± 0.5 45.9 ± 0.3 

Week 40 44.7 ± 0.6 43.9 ± 0.3 44.5 ± 0.5 45.0 ± 0.2 

Week 54 45.3 ± 0.3 45.2 ± 0.5 46.4 ± 0.5 45.1 ± 0.5 

Week 66 47.6 ± 0.4 47.2 ± 0.6 46.0 ± 0.5 48.6 ± 0.5 

Week 79 44.7 ± 0.5 46.4 ± 1.1 49.2 ± 2.5 45.8 ± 0.5 

Hemoglobin (g/dL) 

Week 14 15.1 ± 0.1 15.1 ± 0.1 15.0 ± 0.2 14.9 ± 0.1 

Week 27 15.3 ± 0.1 15.4 ± 0.1 15.4 ± 0.1 15.4 ± 0.1 

Week 40 14.7 ± 0.2 14.6 ± 0.1 14.8 ± 0.2 15.0 ± 0.1 

Week 54 15.1 ± 0.1 14.9 ± 0.2 15.4 ± 0.2 15.0 ± 0.1 

Week 66 15.8 ± 0.2 15.7 ± 0.3 15.1 ± 0.2 16.1 ± 0.2 

Week 79 14.9 ± 0.2 15.4 ± 0.3 16.2 ± 0.8 15.2 ± 0.2 

Erythrocytes (10 /μL) 6 

Week 14 9.43 ± 0.07 9.51 ± 0.02 9.46 ± 0.13 9.37 ± 0.10 

Week 27 10.00 ± 0.05 9.99 ± 0.11 9.95 ± 0.06 9.93 ± 0.09 

Week 40 9.48 ± 0.14 9.29 ± 0.06 9.43 ± 0.13 9.63 ± 0.07 

Week 54 9.60 ± 0.06 9.60 ± 0.09 9.91 ± 0.12 9.67 ± 0.12 

Week 66 9.77 ± 0.08 9.92 ± 0.13 9.62 ± 0.06 10.05 ± 0.11 

Week 79 9.37 ± 0.14 9.84 ± 0.32 10.57 ± 0.63 9.60 ± 0.14 

Reticulocytes (10 /μL) 6 

Week 14 0.22 ± 0.02 0.23 ± 0.02 0.20 ± 0.02 0.20 ± 0.03 

Week 27 0.17 ± 0.02 0.18 ± 0.01 0.16 ± 0.01 0.15 ± 0.02 

Week 40 0.29 ± 0.03 0.22 ± 0.02 0.25 ± 0.03 0.28 ± 0.01 

Week 54 0.31 ± 0.01 0.30 ± 0.02 0.31 ± 0.01 0.28 ± 0.01 

Week 66 0.21 ± 0.02 0.21 ± 0.02 0.20 ± 0.01 0.25 ± 0.02 

Week 79 0.13 ± 0.02 0.18 ± 0.04 0.15 ± 0.02 0.13 ± 0.01 

Nucleated erythrocytes (10 /μL) 3 

Week 14 0.00 ± 0.00 0.01 ± 0.01 0.01 ± 0.01 0.00 ± 0.00 

Week 27 0.01 ± 0.01 0.01 ± 0.01 0.00 ± 0.00 0.00 ± 0.00 

Week 40 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 54 0.00 ± 0.00 0.01 ± 0.01 0.00 ± 0.00 0.01 ± 0.01 

Week 66 0.00 ± 0.00 0.00 ± 0.00b 0.01 ± 0.01 0.00 ± 0.00 

Week 79 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Mean cell volume (fL) 

Week 14 48.7 ± 0.1 48.1 ± 0.3 48.0 ± 0.2* 48.3 ± 0.2 

Week 27 45.7 ± 0.2 45.8 ± 0.3 45.7 ± 0.4 46.3 ± 0.2 

Week 40 47.2 ± 0.3 47.2 ± 0.3 47.2 ± 0.2 46.7 ± 0.2 

Week 54 47.2 ± 0.3 47.1 ± 0.3 46.8 ± 0.3 46.7 ± 0.3 

Week 66 48.7 ± 0.3 47.6 ± 0.3 47.8 ± 0.4 48.3 ± 0.2 

Week 79 47.7 ± 0.4 47.3 ± 0.5 46.7 ± 0.7 47.7 ± 0.6 
258 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K3 

Hematology and Bone Marrow Data for Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Female (continued) 

Hematology (continued) 

Clinical Pathology Groups (continued) 

n 

Week 14 10 9 10 9 

Week 27 10 10 10 10 

Week 40 9 10 10 9 

Week 54 10 10 10 9 

Week 66 10 10 9 10 

Week 79 9 9 10 7 

Mean cell hemoglobin (pg) 

Week 14 16.0 ± 0.1 15.9 ± 0.1 15.9 ± 0.1 16.0 ± 0.1 

Week 27 15.3 ± 0.0 15.4 ± 0.1 15.5 ± 0.1** 15.5 ± 0.1 

Week 40 15.6 ± 0.1 15.7 ± 0.0 15.7 ± 0.1 15.6 ± 0.0 

Week 54 15.8 ± 0.1 15.6 ± 0.1 15.6 ± 0.1 15.5 ± 0.1 

Week 66 16.2 ± 0.1 15.9 ± 0.2 15.7 ± 0.2 16.0 ± 0.0 

Week 79 16.0 ± 0.1 15.7 ± 0.2 15.4 ± 0.3 15.9 ± 0.2 

Mean cell hemoglobin concentration (g/dL) 

Week 14 32.8 ± 0.1 33.0 ± 0.2 33.2 ± 0.1 33.1 ± 0.1 

Week 27 33.5 ± 0.2 33.7 ± 0.2 34.0 ± 0.3 33.5 ± 0.1 

Week 40 33.0 ± 0.1 33.3 ± 0.1 33.3 ± 0.1 33.4 ± 0.2 

Week 54 33.5 ± 0.1 33.1 ± 0.2 33.3 ± 0.1 33.2 ± 0.1 

Week 66 33.3 ± 0.1 33.3 ± 0.2 32.9 ± 0.2 33.1 ± 0.1 

Week 79 33.5 ± 0.2 33.1 ± 0.2 33.0 ± 0.2 33.2 ± 0.2 

Platelets (10 /μL) 3 

Week 14 1,244.9 ± 51.8 1,167.4 ± 51.0 1,185.7 ± 40.0 1,132.3 ± 45.6 

Week 27 997.0 ± 55.2 996.6 ± 38.9 991.1 ± 33.6 1,021.8 ± 84.0 

Week 40 1,115.7 ± 39.3 1,138.4 ± 43.5 1,129.4 ± 39.0 1,134.0 ± 58.1 

Week 54 1,073.3 ± 76.6 1,096.6 ± 43.6 1,113.1 ± 56.5 1,053.3 ± 71.1 

Week 66 1,043.5 ± 42.3 1,135.4 ± 63.0 1,210.6 ± 57.0 1,097.3 ± 39.9 

Week 79 

Leukocytes (10 /μL) 3 1,190.8 ± 27.2 1,392.9 ± 104.8 1,322.8 ± 79.8 1,269.0 ± 62.8 

Week 14 5.26 ± 0.40 6.68 ± 0.47 5.43 ± 0.26 6.25 ± 0.49 

Week 27 6.44 ± 0.44 6.70 ± 0.46 6.97 ± 0.35 6.59 ± 0.50 

Week 40 5.98 ± 0.31 6.06 ± 0.48 6.15 ± 0.27 6.78 ± 0.33 

Week 54 5.44 ± 0.45 5.13 ± 0.37 5.05 ± 0.51 5.10 ± 0.41 

Week 66 5.41 ± 0.33 6.40 ± 0.50b 6.06 ± 0.34 5.26 ± 0.40 

Week 79 5.70 ± 0.57 6.49 ± 0.61 5.76 ± 0.48 6.07 ± 0.46 

Segmented neutrophils (10 /μL) 3 

Week 14 0.70 ± 0.07 0.81 ± 0.09 0.90 ± 0.14 0.94 ± 0.14 

Week 27 1.07 ± 0.14 0.97 ± 0.10 1.08 ± 0.08 0.95 ± 0.17 

Week 40 1.03 ± 0.14 0.92 ± 0.13 1.23 ± 0.16 1.18 ± 0.05 

Week 54 1.21 ± 0.14 1.19 ± 0.11 1.14 ± 0.15 1.01 ± 0.08 

Week 66 1.05 ± 0.06 1.21 ± 0.15b 1.29 ± 0.10 1.04 ± 0.08 

Week 79 1.35 ± 0.18 1.43 ± 0.16 1.10 ± 0.13 1.25 ± 0.18 

Lymphocytes (10 /μL) 3 

Week 14 4.41 ± 0.39 5.69 ± 0.44 4.37 ± 0.24 5.15 ± 0.44 

Week 27 5.16 ± 0.37 5.52 ± 0.42 5.69 ± 0.36 5.42 ± 0.43 

Week 40 4.77 ± 0.22 5.03 ± 0.43 4.80 ± 0.20 5.43 ± 0.36 

Week 54 3.96 ± 0.38 3.65 ± 0.32 3.72 ± 0.44 3.78 ± 0.37 

Week 66 4.06 ± 0.30 4.77 ± 0.38b 4.44 ± 0.33 3.91 ± 0.35 

Week 79 4.25 ± 0.48 4.90 ± 0.58 4.55 ± 0.39 4.73 ± 0.41 
AZT and AZT/"-Interferon A/D, NTP TR 469 259 

TABLE K3 

Hematology and Bone Marrow Data for Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Female (continued) 

Hematology (continued) 

Clinical Pathology Groups (continued) 

n 

Week 14 10 9 10 9 

Week 27 10 10 10 10 

Week 40 9 10 10 9 

Week 54 10 10 10 9 

Week 66 10 10 9 10 

Week 79 9 9 10 7 

Atypical lymphocytes (10 /μL) 3 

Week 14 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 27 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 40 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 54 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 66 0.00 ± 0.00 0.00 ± 0.00b 0.00 ± 0.00 0.00 ± 0.00 

Week 79 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Monocytes (10 /μL) 3 

Week 14 0.04 ± 0.02 0.02 ± 0.01 0.04 ± 0.02 0.04 ± 0.04 

Week 27 0.02 ± 0.01 0.03 ± 0.02 0.04 ± 0.01 0.05 ± 0.02 

Week 40 0.01 ± 0.01 0.00 ± 0.00 0.01 ± 0.01 0.05 ± 0.03 

Week 54 0.14 ± 0.04 0.13 ± 0.03 0.09 ± 0.02 0.15 ± 0.03 

Week 66 0.18 ± 0.02 0.28 ± 0.06b 0.21 ± 0.03 0.17 ± 0.03 

Week 79 0.06 ± 0.03 0.12 ± 0.03 0.08 ± 0.03 0.05 ± 0.03 

Eosinophils (10 /μL) 3 

Week 14 0.10 ± 0.02 0.17 ± 0.03 0.12 ± 0.02 0.12 ± 0.02 

Week 27 0.19 ± 0.05 0.18 ± 0.03 0.17 ± 0.05 0.17 ± 0.04 

Week 40 0.17 ± 0.03 0.12 ± 0.02 0.11 ± 0.03 0.13 ± 0.04 

Week 54 0.14 ± 0.02 0.16 ± 0.03 0.11 ± 0.03 0.16 ± 0.04 

Week 66 0.12 ± 0.03 0.13 ± 0.02b 0.12 ± 0.03 0.15 ± 0.03 

Week 79 0.04 ± 0.02 0.04 ± 0.02 0.03 ± 0.01 0.04 ± 0.03 

Core Groups 

n 10 10 10 10 

Hematocrit (%) 47.4 ± 3.4 43.2 ± 3.0 44.9 ± 2.9 45.3 ± 1.8 

Hemoglobin (g/dL) 

Erythrocytes (10 /μL) 6 

Reticulocytes (10 /μL) 6 

Nucleated erythrocytes (10 /μL) 3 

15.9 ± 1.1 

10.09 ± 0.93 

0.57 ± 0.06 

0.00 ± 0.00 

14.6 ± 1.0 

9.08 ± 0.73 

0.50 ± 0.06 

0.00 ± 0.00 

15.2 ± 0.9 

9.55 ± 0.72 

0.56 ± 0.08 

0.00 ± 0.00 

15.4 ± 0.6 

9.61 ± 0.47 

0.49 ± 0.03 

0.00 ± 0.00 

Mean cell volume (fL) 47.9 ± 1.3 48.2 ± 0.9 47.3 ± 0.5 47.3 ± 0.6 

Mean cell hemoglobin (pg) 16.1 ± 0.4 16.2 ± 0.3 16.0 ± 0.2 16.1 ± 0.2 

Mean cell hemoglobin 

concentration (g/dL) 

Platelets (10 /μL) 3 

Leukocytes (10 /μL) 3 

Segmented neutrophils (10 /μL) 3 

Lymphocytes (10 /μL) 3 

Atypical lymphocytes (10 /μL) 3 

Monocytes (10 /μL) 3 

Eosinophils (10 /μL) 3 

33.5 ± 0.2 

1,071.7 ± 106.2 

5.68 ± 1.03 

1.76 ± 0.25 

3.14 ± 0.92 

0.38 ± 0.08 

0.35 ± 0.04 

0.06 ± 0.02 

33.6 ± 0.2 

1,030.0 ± 129.4 

5.25 ± 0.46 

1.48 ± 0.18 

2.88 ± 0.29 

0.42 ± 0.06 

0.39 ± 0.06 

0.08 ± 0.03 

33.8 ± 0.2 

1,065.3 ± 76.3 

4.64 ± 0.60 

1.52 ± 0.22 

2.31 ± 0.34 

0.42 ± 0.12 

0.32 ± 0.06 

0.05 ± 0.02 

34.1 ± 0.2 

1,050.4 ± 67.8 

4.64 ± 0.47 

1.29 ± 0.08 

2.49 ± 0.35 

0.45 ± 0.07 

0.31 ± 0.05 

0.10 ± 0.03 
260 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K3 

Hematology and Bone Marrow Data for Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Female (continued) 

Bone Marrow Analyses 

Clinical Pathology Groups 

n 

Week 54 10 9 10 9 

Week 66 10 9 9 10 

Week 79 9 9 10 7 

Total femoral count (10 /femur) 6 

Week 54 29.4 ± 1.3 25.3 ± 1.4 27.2 ± 1.0 25.6 ± 1.2 

Week 66 30.0 ± 2.4 33.3 ± 1.9 32.5 ± 1.2 31.0 ± 1.2 

Week 79 31.3 ± 2.4 30.7 ± 1.9 29.3 ± 2.2 28.4 ± 1.2 

M:E ratio 

Week 54 1.84 ± 0.28 2.26 ± 0.21 2.12 ± 0.16 2.29 ± 0.20 

Week 66 2.97 ± 0.21 3.13 ± 0.33 2.84 ± 0.32 2.78 ± 0.15 

Week 79 1.53 ± 0.11 2.09 ± 0.13** 1.53 ± 0.15 2.36 ± 0.13** 

Rubriblasts (10 )

6 

Week 54 0.37 ± 0.06 0.30 ± 0.05 0.43 ± 0.05 0.43 ± 0.06 

Week 66 0.15 ± 0.03 0.17 ± 0.04 0.17 ± 0.03 0.19 ± 0.03 

Week 79 0.63 ± 0.09 0.60 ± 0.10 0.75 ± 0.08 0.44 ± 0.05 

Prorubricytes (10 )

6 

Week 54 0.34 ± 0.05 0.19 ± 0.02** 0.25 ± 0.04 0.16 ± 0.03** 

Week 66 0.18 ± 0.02 0.16 ± 0.02 0.13 ± 0.03 0.18 ± 0.03 

Week 79 1.00 ± 0.13 0.81 ± 0.12 0.83 ± 0.12 0.50 ± 0.08* 

Rubricytes (10 )

6 

Week 54 2.54 ± 0.34 3.16 ± 0.28 2.80 ± 0.30 3.00 ± 0.32 

Week 66 3.41 ± 0.33 3.68 ± 0.39 4.13 ± 0.33 4.17 ± 0.22 

Week 79 6.11 ± 0.64 4.16 ± 0.43** 5.54 ± 0.76 3.04 ± 0.11** 

Metarubricytes (10 )

6 

Week 54 4.12 ± 0.27 1.93 ± 0.21** 2.67 ± 0.17** 2.01 ± 0.19** 

Week 66 1.32 ± 0.22 1.38 ± 0.14 1.46 ± 0.11 0.98 ± 0.10 

Week 79 1.62 ± 0.27 1.61 ± 0.17 1.87 ± 0.18 1.69 ± 0.19 

Myeloblasts (10 )

6 

Week 54 0.50 ± 0.06 0.26 ± 0.05* 0.48 ± 0.07 0.49 ± 0.09 

Week 66 0.34 ± 0.06 0.49 ± 0.05 0.45 ± 0.06 0.40 ± 0.05 

Week 79 0.58 ± 0.07 0.70 ± 0.09 0.70 ± 0.07 0.60 ± 0.06 

Promyelocytes (10 )

6 

Week 54 0.46 ± 0.07 0.29 ± 0.06 0.39 ± 0.07 0.44 ± 0.08 

Week 66 0.29 ± 0.05 0.26 ± 0.05 0.35 ± 0.04 0.41 ± 0.04 

Week 79 0.94 ± 0.09 0.97 ± 0.10 0.83 ± 0.09 0.87 ± 0.06 

Neutrophilic myelocytes (10 )

6 

Week 54 0.69 ± 0.07 0.38 ± 0.05** 0.56 ± 0.05 0.64 ± 0.07 

Week 66 0.58 ± 0.07 0.65 ± 0.17 0.70 ± 0.05 0.74 ± 0.07 

Week 79 1.36 ± 0.23 1.09 ± 0.12 1.15 ± 0.14 0.67 ± 0.06* 

Neutrophilic metamyelocytes (10 )

6 

Week 54 1.59 ± 0.13 1.75 ± 0.14 2.25 ± 0.19 2.42 ± 0.29 

Week 66 3.13 ± 0.24 3.25 ± 0.18 3.36 ± 0.21 2.89 ± 0.17 

Week 79 1.94 ± 0.27 2.73 ± 0.35 1.92 ± 0.21 2.04 ± 0.25 

Neutrophilic bands (10 )

6 

Week 54 0.47 ± 0.10 0.42 ± 0.05 0.41 ± 0.08 0.65 ± 0.11 

Week 66 0.38 ± 0.08 0.37 ± 0.07 0.37 ± 0.06 0.33 ± 0.05 

Week 79 3.67 ± 0.54 1.74 ± 0.15** 2.03 ± 0.23* 1.78 ± 0.17* 
AZT and AZT/"-Interferon A/D, NTP TR 469 261 

TABLE K3 

Hematology and Bone Marrow Data for Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Female (continued) 

Bone Marrow Analyses (continued) 

Clinical Pathology Groups (continued) 

n 

Week 54 10 9 10 9 

Week 66 10 9 9 10 

Week 79 9 9 10 7 

Neutrophilic segments (10 )

6 

Week 54 8.18 ± 1.05 7.98 ± 0.81 7.72 ± 0.34 6.75 ± 0.54 

Week 66 8.89 ± 0.94 9.59 ± 0.45 9.70 ± 0.59 9.10 ± 0.46 

Week 79 4.43 ± 0.39 6.37 ± 0.68 5.75 ± 0.72 5.99 ± 0.42 

Eosinophilic myelocytes (10 )

6 

Week 54 0.039 ± 0.015 0.061 ± 0.019 0.031 ± 0.021 0.058 ± 0.027 

Week 66 0.068 ± 0.026 0.108 ± 0.028 0.071 ± 0.017 0.140 ± 0.029 

Week 79 0.130 ± 0.021 0.158 ± 0.057 0.066 ± 0.018 0.110 ± 0.030 

Eosinophilic metamyelocytes (10 )

6 

Week 54 0.06 ± 0.03 0.01 ± 0.01 0.05 ± 0.04 0.05 ± 0.02 

Week 66 0.07 ± 0.02 0.12 ± 0.03 0.07 ± 0.02 0.15 ± 0.03 

Week 79 0.26 ± 0.04 0.30 ± 0.07 0.12 ± 0.02* 0.34 ± 0.06 

Eosinophilic bands (10 )

6 

Week 54 0.06 ± 0.02 0.07 ± 0.02 0.08 ± 0.03 0.05 ± 0.02 

Week 66 0.08 ± 0.02 0.09 ± 0.03 0.09 ± 0.02 0.12 ± 0.03 

Week 79 0.30 ± 0.06 0.24 ± 0.05 0.19 ± 0.03 0.32 ± 0.07 

Eosinophilic segments (10 )

6 

Week 54 0.37 ± 0.07 0.73 ± 0.13 0.61 ± 0.08 0.74 ± 0.15 

Week 66 0.52 ± 0.11 0.74 ± 0.08 0.60 ± 0.08 0.76 ± 0.06 

Week 79 0.21 ± 0.03 0.47 ± 0.13 0.33 ± 0.05 0.51 ± 0.09* 

Basophilic myelocytes (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic metamyelocytes (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic bands (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic segments (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.030 ± 0.012 0.020 ± 0.008 0.009 ± 0.009 0.011 ± 0.011 

Bone marrow lymphocytes (10 )

6 

Week 54 5.11 ± 0.43 3.26 ± 0.16** 4.18 ± 0.26 3.09 ± 0.37** 

Week 66 5.61 ± 0.58 6.54 ± 1.11 5.65 ± 0.37 5.16 ± 0.29 

Week 79 4.26 ± 0.40 5.02 ± 0.49 4.19 ± 0.40 6.13 ± 0.55 

Bone marrow macrophages (10 )

6 

Week 54 0.06 ± 0.02 0.07 ± 0.03 0.08 ± 0.02 0.07 ± 0.03 

Week 66 0.11 ± 0.02 0.14 ± 0.02 0.14 ± 0.03 0.09 ± 0.03 

Week 79 0.19 ± 0.04 0.16 ± 0.02 0.18 ± 0.04 0.12 ± 0.02 
262 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K3 

Hematology and Bone Marrow Data for Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Female (continued) 

Bone Marrow Analyses (continued) 

Clinical Pathology Groups (continued) 

n 

Week 54 10 9 10 9 

Week 66 10 9 9 10 

Week 79 9 9 10 7 

Bone marrow monocytes (10 )

6 

Week 54 0.07 ± 0.03 0.21 ± 0.05* 0.14 ± 0.04 0.18 ± 0.05 

Week 66 0.04 ± 0.02 0.10 ± 0.03 0.06 ± 0.02 0.04 ± 0.01 

Week 79 0.54 ± 0.06 0.47 ± 0.10 0.48 ± 0.07 0.34 ± 0.06 

Megakaryo cells (10 )

6 

Week 54 0.11 ± 0.03 0.05 ± 0.01 0.08 ± 0.02 0.08 ± 0.03 

Week 66 0.13 ± 0.02 0.15 ± 0.03 0.09 ± 0.01 0.14 ± 0.03 

Week 79 0.22 ± 0.03 0.10 ± 0.02** 0.13 ± 0.02 0.07 ± 0.01** 

Plasma cells (10 )

6 

Week 54 0.25 ± 0.05 0.21 ± 0.06 0.20 ± 0.04 0.22 ± 0.04 

Week 66 0.36 ± 0.08 0.35 ± 0.07 0.33 ± 0.04 0.38 ± 0.06 

Week 79 0.31 ± 0.05 0.31 ± 0.05 0.44 ± 0.06 0.48 ± 0.11 

Mitotic figures (10 )

6 

Week 54 0.46 ± 0.07 0.30 ± 0.04 0.50 ± 0.03 0.37 ± 0.06 

Week 66 0.28 ± 0.07 0.31 ± 0.04 0.34 ± 0.07 0.35 ± 0.02 

Week 79 0.07 ± 0.02 0.09 ± 0.05 0.10 ± 0.03 0.13 ± 0.03 

Fat cells (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Mast cells (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.005 ± 0.005 0.004 ± 0.004 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Smudge cells (10 )

6 

Week 54 3.56 ± 0.38 3.63 ± 0.40 3.31 ± 0.25 3.67 ± 0.49 

Week 66 3.53 ± 0.44 4.70 ± 0.37 4.25 ± 0.30 4.20 ± 0.41 

Week 79 2.52 ± 0.22 2.54 ± 0.22 1.72 ± 0.24* 2.19 ± 0.14 

Osteoblasts (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Osteoclasts (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.536 ± 0.536 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.008 ± 0.008 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Other bone marrow cells (10 )

6 

Week 54 0.014 ± 0.010 0.000 ± 0.000 0.010 ± 0.007 0.000 ± 0.000 

Week 66 0.011 ± 0.008 0.000 ± 0.000 0.006 ± 0.006 0.086 ± 0.017** 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Neutrophilic hypersegments (10 )

6 

Week 54 0.00 ± 0.00 0.06 ± 0.03** 0.00 ± 0.00 0.00 ± 0.00 

Week 66 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 79 0.16 ± 0.03 0.20 ± 0.04 0.14 ± 0.03 0.20 ± 0.03 
AZT and AZT/"-Interferon A/D, NTP TR 469 263 

TABLE K3 

Hematology and Bone Marrow Data for Mice in the 2-Year Subcutaneous Study of "-Interferon A/D 

5,000 U 500 U 5,000 U 

Vehicle Control "-IFN A "-IFN A/D "-IFN A/D 

Female (continued) 

Bone Marrow Analyses (continued) 

Core Groups 

n 10 10 9 10 

Total femoral count (10 /femur) 6 29.8 ± 1.0 31.9 ± 1.6 31.0 ± 2.9 26.3 ± 2.5 

M:E ratio 1.57 ± 0.16 1.64 ± 0.19 1.97 ± 0.28c 1.53 ± 0.14 

Rubriblasts (10 )

6 

Prorubricytes (10 )

6 

Rubricytes (10 )

6 

Metarubricytes (10 )

6 

Myeloblasts (10 )

6 

Promyelocytes (10 )

6 

Neutrophilic myelocytes (10 )

6 

Neutrophilic metamyelocytes (10 )

6 

Neutrophilic bands (10 )

6 

Neutrophilic segments (10 )

6 

Eosinophilic myelocytes (10 )

6 

Eosinophilic metamyelocytes (10 )

6 

Eosinophilic bands (10 )

6 

Eosinophilic segments (10 )

6 

Basophilic myelocytes (10 )

6 

Basophilic metamyelocytes (10 )

6 

Basophilic bands (10 )

6 

Basophilic segments (10 )

6 

Bone marrow lymphocytes (10 )

6 

Bone marrow macrophages (10 )

6 

Bone marrow monocytes (10 )

6 

Megakaryo cells (10 )

6 

Plasma cells (10 )

6 

Mitotic figures (10 )

6 

Fat cells (10 )

6 

Mast cells (10 )

6 

Smudge cells (10 )

6 

Osteoblasts (10 )

6 

Osteoclasts (10 )

6 

Other bone marrow cells (10 )

6 

Neutrophilic hypersegments (10 )

6 

0.45 ± 0.06 

1.53 ± 0.14 

5.49 ± 0.34 

2.03 ± 0.24 

0.32 ± 0.05 

0.41 ± 0.07 

0.97 ± 0.12 

1.44 ± 0.27 

2.98 ± 0.52 

7.74 ± 0.93 

0.015 ± 0.011 

0.04 ± 0.01 

0.14 ± 0.04 

0.27 ± 0.05 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

2.44 ± 0.34 

0.20 ± 0.04 

0.31 ± 0.06 

0.14 ± 0.03 

0.40 ± 0.07 

0.21 ± 0.05 

0.000 ± 0.000 

0.000 ± 0.000 

2.25 ± 0.34 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.02 ± 0.01 

0.43 ± 0.05 

1.61 ± 0.19 

6.23 ± 0.72 

2.01 ± 0.33 

0.32 ± 0.05 

0.51 ± 0.10 

0.72 ± 0.14 

1.61 ± 0.24 

2.56 ± 0.51 

9.19 ± 0.67 

0.017 ± 0.017 

0.04 ± 0.02 

0.23 ± 0.06 

0.27 ± 0.04 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

2.50 ± 0.37 

0.16 ± 0.03 

0.27 ± 0.04 

0.13 ± 0.02 

0.68 ± 0.13 

0.32 ± 0.05 

0.000 ± 0.000 

0.000 ± 0.000 

2.11 ± 0.17 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.05 ± 0.02 

0.37 ± 0.05 

1.53 ± 0.39 

5.35 ± 0.90 

2.02 ± 0.58 

0.37 ± 0.04 

0.46 ± 0.06 

0.96 ± 0.12 

1.52 ± 0.26 

2.97 ± 0.52 

8.85 ± 0.77 

0.037 ± 0.019 

0.02 ± 0.02 

0.12 ± 0.03 

0.26 ± 0.06 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

2.64 ± 0.75 

0.20 ± 0.08 

0.32 ± 0.10 

0.15 ± 0.04 

0.71 ± 0.19 

0.18 ± 0.04 

0.000 ± 0.000 

0.000 ± 0.000 

1.97 ± 0.41 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.04 ± 0.02 

0.41 ± 0.05 

1.34 ± 0.19 

4.91 ± 0.42 

1.63 ± 0.28 

0.23 ± 0.04 

0.31 ± 0.07 

0.80 ± 0.14 

1.61 ± 0.28 

1.86 ± 0.33 

6.86 ± 1.14 

0.026 ± 0.018 

0.06 ± 0.03 

0.27 ± 0.06 

0.32 ± 0.07 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

2.29 ± 0.42 

0.19 ± 0.05 

0.27 ± 0.06 

0.12 ± 0.04 

0.57 ± 0.15 

0.19 ± 0.04 

0.000 ± 0.000 

0.000 ± 0.000 

1.99 ± 0.34 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.02 ± 0.01 

* Significantly different (P#0.05) from the control group by Dunn’s or Shirley’s test 

** P#0.01 a Mean ± standard error. Statistical tests were performed on unrounded data. b n=9
 

n=10
 c 
264 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K4 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/Da 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Male 

Hematology 

Clinical Pathology Groups 

n 

Week 14 10 10 10 10 

Week 27 10 10 10 10 

Week 40 10 10 9 10 

Week 54 9 8 8 7 

Week 65 10 10 9 10 

Week 79 10 10 7 8 

Hematocrit (%) 

Week 14 46.0 ± 0.6 43.5 ± 0.3** 44.2 ± 0.3 43.7 ± 0.5* 

Week 27 44.9 ± 0.7 44.0 ± 0.5 42.6 ± 1.3 42.7 ± 0.6 

Week 40 44.9 ± 0.8 42.7 ± 1.0 44.3 ± 0.6 43.7 ± 0.8 

Week 54 44.2 ± 0.5 42.3 ± 0.9 43.7 ± 0.6 40.8 ± 0.8* 

Week 65 43.1 ± 0.8 42.2 ± 0.6 41.5 ± 0.5 38.8 ± 1.2** 

Week 79 41.3 ± 2.1 35.8 ± 2.1 37.5 ± 1.4 38.1 ± 1.0 

Hemoglobin (g/dL) 

Week 14 15.5 ± 0.2 14.7 ± 0.1** 14.9 ± 0.1** 14.7 ± 0.1** 

Week 27 15.1 ± 0.3 14.7 ± 0.2 14.2 ± 0.4 14.2 ± 0.2 

Week 40 14.7 ± 0.3 13.8 ± 0.4 14.5 ± 0.2 14.3 ± 0.3 

Week 54 14.6 ± 0.2 13.8 ± 0.3 14.5 ± 0.3 13.4 ± 0.3* 

Week 65 14.3 ± 0.3 13.8 ± 0.2 13.8 ± 0.2 12.6 ± 0.5** 

Week 79 13.8 ± 0.7 12.0 ± 0.7 12.5 ± 0.6 12.6 ± 0.4 

Erythrocytes (10 /μL) 6 

Week 14 9.99 ± 0.10 9.22 ± 0.04** 9.20 ± 0.06** 8.92 ± 0.10** 

Week 27 9.82 ± 0.17 9.25 ± 0.10** 8.96 ± 0.21** 8.84 ± 0.13** 

Week 40 9.69 ± 0.13 9.09 ± 0.23* 8.90 ± 0.14** 8.71 ± 0.11** 

Week 54 9.13 ± 0.13 8.70 ± 0.18 8.53 ± 0.10** 7.98 ± 0.17** 

Week 65 9.01 ± 0.21 8.55 ± 0.15* 8.38 ± 0.09* 7.51 ± 0.36** 

Week 79 9.18 ± 0.68 7.43 ± 0.53 7.42 ± 0.45 7.59 ± 0.20 

Reticulocytes (10 /μL) 6 

Week 14 0.23 ± 0.01 0.22 ± 0.02 0.25 ± 0.01 0.23 ± 0.01 

Week 27 0.19 ± 0.02 0.19 ± 0.01 0.21 ± 0.02 0.20 ± 0.02 

Week 40 0.26 ± 0.03 0.32 ± 0.05 0.25 ± 0.04 0.24 ± 0.02 

Week 54 0.18 ± 0.02 0.18 ± 0.02 0.13 ± 0.01 0.17 ± 0.01 

Week 65 0.43 ± 0.04 0.40 ± 0.03 0.41 ± 0.04 0.47 ± 0.06 

Week 79 0.25 ± 0.03 0.31 ± 0.03 0.29 ± 0.11 0.25 ± 0.03 

Nucleated erythrocytes (10 /μL) 3 

Week 14 0.00 ± 0.00 0.01 ± 0.01 0.00 ± 0.00 0.00 ± 0.00 

Week 27 0.00 ± 0.00 0.02 ± 0.02 0.02 ± 0.02 0.01 ± 0.01 

Week 40 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 54 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 65 0.00 ± 0.00 0.00 ± 0.00b 0.00 ± 0.00 0.00 ± 0.00 

Week 79 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Mean cell volume (fL) 

Week 14 46.0 ± 0.3 47.2 ± 0.2** 48.1 ± 0.2** 49.0 ± 0.3** 

Week 27 45.8 ± 0.2 47.6 ± 0.3** 47.5 ± 0.5** 48.3 ± 0.4** 

Week 40 46.3 ± 0.6 47.0 ± 0.5 49.8 ± 0.6** 50.2 ± 0.6** 

Week 54 48.5 ± 0.8 48.6 ± 0.5 51.2 ± 0.4** 51.1 ± 0.5* 

Week 65 47.9 ± 0.6 49.4 ± 0.4 49.4 ± 0.4 52.3 ± 1.5** 

Week 79 45.6 ± 1.1 48.7 ± 1.4 51.1 ± 1.9** 50.1 ± 0.6** 
AZT and AZT/"-Interferon A/D, NTP TR 469 265 

TABLE K4 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Male (continued) 

Hematology (continued) 

Clinical Pathology Groups (continued) 

n 

Week 14 10 10 10 10 

Week 27 10 10 10 10 

Week 40 10 10 9 10 

Week 54 9 8 8 7 

Week 65 10 10 9 10 

Week 79 10 10 7 8 

Mean cell hemoglobin (pg) 

Week 14 15.5 ± 0.0 16.0 ± 0.1** 16.2 ± 0.1** 16.5 ± 0.1** 

Week 27 15.3 ± 0.1 15.9 ± 0.1** 15.9 ± 0.2* 16.0 ± 0.1** 

Week 40 15.2 ± 0.2 15.2 ± 0.2 16.3 ± 0.3* 16.4 ± 0.2** 

Week 54 16.0 ± 0.3 15.9 ± 0.2 17.0 ± 0.2* 16.7 ± 0.2 

Week 65 15.9 ± 0.2 16.1 ± 0.2 16.5 ± 0.1* 16.9 ± 0.3** 

Week 79 15.3 ± 0.4 16.3 ± 0.5 17.0 ± 0.4** 16.6 ± 0.3* 

Mean cell hemoglobin concentration (g/dL) 

Week 14 33.7 ± 0.2 33.9 ± 0.1 33.6 ± 0.1 33.7 ± 0.1 

Week 27 33.5 ± 0.2 33.5 ± 0.1 33.4 ± 0.1 33.2 ± 0.1 

Week 40 32.8 ± 0.2 32.4 ± 0.4 32.7 ± 0.2 32.7 ± 0.2 

Week 54 33.0 ± 0.1 32.7 ± 0.3 33.3 ± 0.2 32.7 ± 0.2 

Week 65 33.2 ± 0.2 32.7 ± 0.2 33.4 ± 0.2 32.4 ± 0.3 

Week 79 33.5 ± 0.3 33.5 ± 0.2 33.3 ± 0.5 33.2 ± 0.3 

Platelets (10 /μL) 3 

Week 14 1,239.1 ± 31.8 1,299.1 ± 41.8 1,364.0 ± 50.4 1,361.7 ± 28.0 

Week 27 1,278.3 ± 57.6 1,288.6 ± 57.6 1,303.1 ± 113.9 1,419.9 ± 59.2 

Week 40 1,374.1 ± 58.4 1,420.6 ± 78.2 1,481.4 ± 86.9 1,411.6 ± 78.1 

Week 54 1,303.6 ± 109.2 1,444.6 ± 71.0 1,363.8 ± 45.7 1,548.4 ± 60.7 

Week 65 1,689.4 ± 89.2 1,749.2 ± 93.6 1,843.7 ± 126.4 1,790.4 ± 172.3 

Week 79 

Leukocytes (10 /μL) 3 1,435.9 ± 111.9 1,403.8 ± 68.7 1,804.1 ± 69.8* 1,843.1 ± 79.0* 

Week 14 7.77 ± 0.35 8.37 ± 0.36 7.64 ± 0.16 7.65 ± 0.54 

Week 27 8.70 ± 0.56 8.17 ± 0.32 8.45 ± 0.53 9.99 ± 0.41 

Week 40 9.67 ± 0.69 10.89 ± 0.74 9.08 ± 0.63 8.56 ± 0.63 

Week 54 10.92 ± 1.16 12.26 ± 0.56 9.01 ± 1.23 12.37 ± 1.06 

Week 65 10.86 ± 0.88 11.05 ± 0.59 10.36 ± 0.67 11.60 ± 0.97 

Week 79 12.26 ± 0.94 14.72 ± 0.57 10.02 ± 0.86 11.36 ± 1.77 

Segmented neutrophils (10 /μL) 3 

Week 14 1.16 ± 0.08 1.38 ± 0.11 1.34 ± 0.11 1.06 ± 0.12 

Week 27 2.10 ± 0.36 1.60 ± 0.13 1.65 ± 0.29 2.31 ± 0.16 

Week 40 2.25 ± 0.20 2.77 ± 0.29 1.89 ± 0.19 1.93 ± 0.24 

Week 54 3.14 ± 0.52 2.39 ± 0.33 2.60 ± 0.53 2.62 ± 0.27 

Week 65 2.52 ± 0.26 2.54 ± 0.24b 2.47 ± 0.24 2.38 ± 0.25 

Week 79 3.43 ± 0.44 3.82 ± 0.33 2.73 ± 0.26 2.83 ± 0.53 

Lymphocytes (10 /μL) 3 

Week 14 6.50 ± 0.30 6.84 ± 0.25 6.16 ± 0.14 6.48 ± 0.44 

Week 27 6.32 ± 0.38 6.31 ± 0.33 6.50 ± 0.31 7.23 ± 0.31 

Week 40 6.85 ± 0.50 7.31 ± 0.49 6.59 ± 0.40 6.26 ± 0.40 

Week 54 7.37 ± 0.75 9.62 ± 0.57 6.22 ± 0.83 9.51 ± 0.93 

Week 65 7.81 ± 0.65 8.18 ± 0.50b 7.38 ± 0.68 8.76 ± 0.78 

Week 79 7.86 ± 0.59 9.67 ± 0.81 6.77 ± 0.67 7.92 ± 1.15 
266 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K4 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Male (continued) 

Hematology (continued) 

Clinical Pathology Groups (continued) 

n 

Week 14 10 10 10 10 

Week 27 10 10 10 10 

Week 40 10 10 9 10 

Week 54 9 8 8 7 

Week 65 10 10 9 10 

Week 79 10 10 7 8 

Atypical lymphocytes (10 /μL) 3 

Week 14 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 27 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 40 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 54 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 65 0.00 ± 0.00 0.00 ± 0.00b 0.00 ± 0.00 0.00 ± 0.00 

Week 79 0.12 ± 0.04 0.12 ± 0.04 0.03 ± 0.02 0.04 ± 0.04 

Monocytes (10 /μL) 3 

Week 14 0.06 ± 0.02 0.06 ± 0.02 0.10 ± 0.02 0.07 ± 0.02 

Week 27 0.08 ± 0.02 0.03 ± 0.02 0.07 ± 0.02 0.14 ± 0.03 

Week 40 0.39 ± 0.11 0.58 ± 0.14 0.42 ± 0.14 0.21 ± 0.06 

Week 54 0.33 ± 0.11 0.17 ± 0.06 0.16 ± 0.07 0.17 ± 0.10 

Week 65 0.39 ± 0.07 0.42 ± 0.10b 0.38 ± 0.06 0.31 ± 0.05 

Week 79 0.55 ± 0.16 0.69 ± 0.24 0.29 ± 0.05 0.37 ± 0.05 

Eosinophils (10 /μL) 3 

Week 14 0.05 ± 0.02 0.09 ± 0.03 0.05 ± 0.02 0.04 ± 0.02 

Week 27 0.22 ± 0.06 0.23 ± 0.04 0.23 ± 0.04 0.31 ± 0.06 

Week 40 0.17 ± 0.06 0.23 ± 0.04 0.19 ± 0.04 0.17 ± 0.07 

Week 54 0.09 ± 0.04 0.08 ± 0.03 0.04 ± 0.02 0.07 ± 0.04 

Week 65 0.15 ± 0.07 0.06 ± 0.03b 0.12 ± 0.05 0.16 ± 0.05 

Week 79 0.20 ± 0.07 0.16 ± 0.04 0.14 ± 0.04 0.16 ± 0.07 

Core Groups 

n 10 10 10 10 

Hematocrit (%) 40.1 ± 1.4 39.2 ± 2.2 41.4 ± 2.9 37.5 ± 1.1 

Hemoglobin (g/dL) 

Erythrocytes (10 /μL) 6 

Reticulocytes (10 /μL) 6 

Nucleated erythrocytes (10 /μL) 3 

13.6 ± 0.5 

8.82 ± 0.35 

0.31 ± 0.02 

0.00 ± 0.00 

13.0 ± 0.8 

7.97 ± 0.55 

0.31 ± 0.04 

0.00 ± 0.00 

13.8 ± 1.0 

8.38 ± 0.59 

0.36 ± 0.03 

0.00 ± 0.00b 

12.5 ± 0.3 

7.35 ± 0.27* 

0.29 ± 0.02 

0.00 ± 0.00 

Mean cell volume (fL) 45.6 ± 0.6 49.6 ± 1.2** 49.7 ± 1.6** 51.2 ± 0.7** 

Mean cell hemoglobin (pg) 15.5 ± 0.2 16.5 ± 0.4* 16.6 ± 0.5* 17.1 ± 0.3** 

Mean cell hemoglobin 

concentration (g/dL) 

Platelets (10 /μL) 3 

Leukocytes (10 /μL) 3 

Segmented neutrophils (10 /μL) 3 

Lymphocytes (10 /μL) 3 

Atypical lymphocytes (10 /μL) 3 

Monocytes (10 /μL) 3 

Eosinophils (10 /μL) 3 

33.9 ± 0.3 

1,672.9 ± 89.3 

14.65 ± 1.58 

3.64 ± 0.39 

6.44 ± 0.71 

3.61 ± 0.66 

0.88 ± 0.19 

0.09 ± 0.02 

33.2 ± 0.3 

1,881.4 ± 222.0 

17.00 ± 1.20 

4.44 ± 0.72 

7.62 ± 1.17 

3.85 ± 0.40 

0.92 ± 0.13 

0.18 ± 0.05 

33.5 ± 0.2 

1,940.2 ± 146.2 

10.84 ± 0.58b 

2.68 ± 0.18b 

4.88 ± 0.48b 

2.60 ± 0.30b 

0.55 ± 0.09b 

0.14 ± 0.03b 

33.4 ± 0.2 

2,138.9 ± 167.8 

13.10 ± 1.18 

2.78 ± 0.17 

6.49 ± 0.64 

3.20 ± 0.51 

0.45 ± 0.10 

0.19 ± 0.05 
AZT and AZT/"-Interferon A/D, NTP TR 469 267 

TABLE K4 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Male (continued) 

Bone Marrow Analyses 

Clinical Pathology Groups 

n 

Week 54 10 10 10 10 

Week 65 10 10 9 10 

Week 79 9 10 7 7 

Total femoral count (10 /femur) 6 

Week 54 30.9 ± 1.6 27.9 ± 1.0 27.9 ± 1.1 30.5 ± 0.8 

Week 65 31.2 ± 2.4 34.8 ± 0.8 34.5 ± 1.2 34.8 ± 1.3 

Week 79 27.8 ± 1.8 26.6 ± 1.9 30.1 ± 1.7 28.9 ± 1.0 

M:E ratio 

Week 54 2.68 ± 0.37 2.12 ± 0.06 2.90 ± 0.17 3.37 ± 0.43 

Week 65 3.00 ± 0.26 2.64 ± 0.25 3.20 ± 0.36 2.77 ± 0.23 

Week 79 2.37 ± 0.34 3.92 ± 0.37** 2.89 ± 0.30 2.24 ± 0.27 

Rubriblasts (10 )

6 

Week 54 0.42 ± 0.06 0.36 ± 0.03 0.42 ± 0.05 0.42 ± 0.05 

Week 65 0.31 ± 0.05 0.34 ± 0.04 0.33 ± 0.07 0.28 ± 0.05 

Week 79 0.32 ± 0.03 0.32 ± 0.07 0.43 ± 0.10 0.30 ± 0.05 

Prorubricytes (10 )

6 

Week 54 0.79 ± 0.13 0.76 ± 0.05 0.73 ± 0.08 1.11 ± 0.17 

Week 65 1.05 ± 0.16 1.41 ± 0.23 1.30 ± 0.24 1.56 ± 0.11 

Week 79 1.19 ± 0.16 0.77 ± 0.11 1.10 ± 0.14 1.27 ± 0.13 

Rubricytes (10 )

6 

Week 54 3.95 ± 0.45 4.27 ± 0.20 3.14 ± 0.21 2.98 ± 0.28 

Week 65 3.80 ± 0.35 4.58 ± 0.37 4.07 ± 0.40 4.49 ± 0.46 

Week 79 3.74 ± 0.45 2.33 ± 0.12* 3.78 ± 0.46 4.16 ± 0.45 

Metarubricytes (10 )

6 

Week 54 1.37 ± 0.17 1.04 ± 0.12 0.90 ± 0.12* 0.52 ± 0.05** 

Week 65 0.72 ± 0.16 1.03 ± 0.20 0.70 ± 0.12 0.69 ± 0.11 

Week 79 1.11 ± 0.15 0.60 ± 0.12* 0.61 ± 0.06* 0.75 ± 0.19 

Myeloblasts (10 )

6 

Week 54 0.61 ± 0.09 0.47 ± 0.04 0.66 ± 0.10 0.82 ± 0.12 

Week 65 0.63 ± 0.11 0.77 ± 0.10 0.76 ± 0.15 0.69 ± 0.06 

Week 79 0.40 ± 0.06 0.53 ± 0.07 0.59 ± 0.07 0.38 ± 0.03 

Promyelocytes (10 )

6 

Week 54 0.84 ± 0.15 0.94 ± 0.07 0.77 ± 0.15 1.06 ± 0.14 

Week 65 0.94 ± 0.14 1.13 ± 0.10 1.05 ± 0.11 1.20 ± 0.13 

Week 79 0.59 ± 0.11 0.45 ± 0.03 0.77 ± 0.10 0.45 ± 0.08 

Neutrophilic myelocytes (10 )

6 

Week 54 1.02 ± 0.21 0.68 ± 0.06 1.35 ± 0.21 1.36 ± 0.12 

Week 65 1.39 ± 0.19 1.88 ± 0.25 1.69 ± 0.16 2.04 ± 0.19 

Week 79 1.47 ± 0.28 0.96 ± 0.13 1.43 ± 0.11 1.24 ± 0.13 

Neutrophilic metamyelocytes (10 )

6 

Week 54 1.45 ± 0.11 1.31 ± 0.09 1.23 ± 0.12 0.98 ± 0.10** 

Week 65 2.30 ± 0.43 1.93 ± 0.12 2.01 ± 0.24 2.09 ± 0.23 

Week 79 1.74 ± 0.46 1.03 ± 0.07 1.74 ± 0.14 1.48 ± 0.15 

Neutrophilic bands (10 )

6 

Week 54 2.04 ± 0.31 2.74 ± 0.26 1.71 ± 0.19 2.26 ± 0.15 

Week 65 3.20 ± 0.34 3.25 ± 0.26 4.07 ± 0.38 4.03 ± 0.58 

Week 79 3.54 ± 0.35 5.26 ± 0.63* 4.57 ± 0.38 4.01 ± 0.33 
268 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K4 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Male (continued) 

Bone Marrow Analyses (continued) 

Clinical Pathology Groups (continued) 

n 

Week 54 10 10 10 10 

Week 65 10 10 9 10 

Week 79 9 10 7 7 

Neutrophilic segments (10 )

6 

Week 54 9.24 ± 0.61 6.87 ± 0.42* 8.68 ± 0.84 8.30 ± 0.76 

Week 65 7.24 ± 0.47 8.58 ± 0.36 8.47 ± 0.81 7.73 ± 0.63 

Week 79 5.81 ± 0.48 6.60 ± 0.64 6.46 ± 0.71 5.41 ± 0.40 

Eosinophilic myelocytes (10 )

6 

Week 54 0.046 ± 0.032 0.096 ± 0.037 0.036 ± 0.014 0.058 ± 0.019 

Week 65 0.053 ± 0.020 0.045 ± 0.022 0.079 ± 0.028 0.079 ± 0.021 

Week 79 0.024 ± 0.013 0.013 ± 0.009 0.021 ± 0.014 0.041 ± 0.016 

Eosinophilic metamyelocytes (10 )

6 

Week 54 0.05 ± 0.02 0.09 ± 0.03 0.07 ± 0.02 0.17 ± 0.04* 

Week 65 0.17 ± 0.02 0.16 ± 0.03 0.12 ± 0.03 0.13 ± 0.04 

Week 79 0.06 ± 0.02 0.07 ± 0.02 0.12 ± 0.03 0.13 ± 0.01 

Eosinophilic bands (10 )

6 

Week 54 0.20 ± 0.05 0.15 ± 0.03 0.09 ± 0.02 0.21 ± 0.03 

Week 65 0.26 ± 0.04 0.30 ± 0.04 0.24 ± 0.05 0.29 ± 0.04 

Week 79 0.26 ± 0.04 0.25 ± 0.05 0.24 ± 0.06 0.23 ± 0.03 

Eosinophilic segments (10 )

6 

Week 54 0.28 ± 0.04 0.20 ± 0.03 0.35 ± 0.05 0.26 ± 0.05 

Week 65 0.26 ± 0.05 0.25 ± 0.05 0.26 ± 0.08 0.22 ± 0.05 

Week 79 0.16 ± 0.03 0.31 ± 0.07 0.24 ± 0.04 0.23 ± 0.04 

Basophilic myelocytes (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 65 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic metamyelocytes (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 65 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic bands (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 65 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic segments (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 65 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Bone marrow lymphocytes (10 )

6 

Week 54 4.08 ± 0.58 2.94 ± 0.16 3.75 ± 0.35 5.29 ± 0.74 

Week 65 4.33 ± 0.39 4.31 ± 0.38 4.02 ± 0.43 4.43 ± 0.58 

Week 79 3.73 ± 0.42 3.25 ± 0.37 3.95 ± 0.46 4.25 ± 0.34 

Bone marrow macrophages (10 )

6 

Week 54 0.16 ± 0.04 0.13 ± 0.02 0.09 ± 0.02 0.15 ± 0.03 

Week 65 0.13 ± 0.03 0.07 ± 0.03 0.13 ± 0.03 0.13 ± 0.02 

Week 79 0.20 ± 0.03 0.11 ± 0.04* 0.13 ± 0.01 0.26 ± 0.04 
AZT and AZT/"-Interferon A/D, NTP TR 469 269 

TABLE K4 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Male (continued) 

Bone Marrow Analyses (continued) 

Clinical Pathology Groups (continued) 

n 

Week 54 10 10 10 10 

Week 65 10 10 9 10 

Week 79 9 10 7 7 

Bone marrow monocytes (10 )

6 

Week 54 0.29 ± 0.05 0.25 ± 0.03 0.20 ± 0.04 0.27 ± 0.03 

Week 65 0.27 ± 0.09 0.21 ± 0.03 0.23 ± 0.04 0.14 ± 0.04 

Week 79 0.30 ± 0.05 0.22 ± 0.06 0.21 ± 0.04 0.33 ± 0.04 

Megakaryo cells (10 )

6 

Week 54 0.08 ± 0.03 0.14 ± 0.04 0.06 ± 0.01 0.12 ± 0.03 

Week 65 0.03 ± 0.01 0.02 ± 0.01 0.04 ± 0.02 0.05 ± 0.01 

Week 79 0.06 ± 0.02 0.06 ± 0.02 0.12 ± 0.01 0.06 ± 0.02 

Plasma cells (10 )

6 

Week 54 0.18 ± 0.04 0.25 ± 0.03 0.27 ± 0.02 0.28 ± 0.05 

Week 65 0.18 ± 0.04 0.19 ± 0.06 0.36 ± 0.09 0.35 ± 0.10 

Week 79 0.35 ± 0.07 0.54 ± 0.15 0.38 ± 0.07 0.24 ± 0.02 

Mitotic figures (10 )

6 

Week 54 0.25 ± 0.04 0.16 ± 0.02 0.24 ± 0.03 0.28 ± 0.05 

Week 65 0.26 ± 0.04 0.32 ± 0.03 0.26 ± 0.07 0.29 ± 0.04 

Week 79 0.35 ± 0.04 0.25 ± 0.03 0.41 ± 0.06 0.30 ± 0.03 

Fat cells (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 65 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Mast cells (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 65 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Smudge cells (10 )

6 

Week 54 3.60 ± 0.25 4.06 ± 0.15 3.13 ± 0.25 3.56 ± 0.23 

Week 65 3.70 ± 0.32 4.02 ± 0.37 4.32 ± 0.27 3.94 ± 0.25 

Week 79 2.44 ± 0.25 2.69 ± 0.23 2.82 ± 0.26 3.34 ± 0.26 

Osteoblasts (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 65 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Osteoclasts (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 65 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Other bone marrow cells (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 65 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Neutrophilic hypersegments (10 )

6 

Week 54 0.08 ± 0.03 0.13 ± 0.02 0.19 ± 0.05 0.19 ± 0.04 

Week 65 0.67 ± 0.18 1.09 ± 0.27 1.20 ± 0.22 0.78 ± 0.12 

Week 79 0.32 ± 0.10 0.31 ± 0.06 0.39 ± 0.19 0.30 ± 0.08 
270 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K4 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Male (continued) 

Bone Marrow Analyses (continued) 

Core Groups 

n 10 9 10 10 

Total femoral count (10 /femur) 6 33.5 ± 2.4 35.4 ± 2.3 33.9 ± 1.6 34.5 ± 1.7 

M:E ratio 4.33 ± 0.75 4.99 ± 0.60 3.30 ± 0.39 4.36 ± 0.56 

Rubriblasts (10 )

6 

Prorubricytes (10 )

6 

Rubricytes (10 )

6 

Metarubricytes (10 )

6 

Myeloblasts (10 )

6 

Promyelocytes (10 )

6 

Neutrophilic myelocytes (10 )

6 

Neutrophilic metamyelocytes (10 )

6 

Neutrophilic bands (10 )

6 

Neutrophilic segments (10 )

6 

Eosinophilic myelocytes (10 )

6 

Eosinophilic metamyelocytes (10 )

6 

Eosinophilic bands (10 )

6 

Eosinophilic segments (10 )

6 

Basophilic myelocytes (10 )

6 

Basophilic metamyelocytes (10 )

6 

Basophilic bands (10 )

6 

Basophilic segments (10 )

6 

Bone marrow lymphocytes (10 )

6 

Bone marrow macrophages (10 )

6 

Bone marrow monocytes (10 )

6 

Megakaryo cells (10 )

6 

Plasma cells (10 )

6 

Mitotic figures (10 )

6 

Fat cells (10 )

6 

Mast cells (10 )

6 

Smudge cells (10 )

6 

Osteoblasts (10 )

6 

Osteoclasts (10 )

6 

Other bone marrow cells (10 )

6 

Neutrophilic hypersegments (10 )

6 

0.31 ± 0.05 

0.62 ± 0.13 

3.16 ± 0.40 

0.48 ± 0.10 

0.62 ± 0.08 

0.70 ± 0.11 

1.49 ± 0.28 

1.82 ± 0.23 

2.93 ± 0.40 

9.53 ± 0.87 

0.071 ± 0.025 

0.06 ± 0.02 

0.14 ± 0.05 

0.23 ± 0.05 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.006 ± 0.006 

5.08 ± 1.06 

0.19 ± 0.04 

0.33 ± 0.05 

0.07 ± 0.02 

0.52 ± 0.13 

0.21 ± 0.04 

0.000 ± 0.000 

0.000 ± 0.000 

4.95 ± 0.42 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.03 ± 0.02 

0.23 ± 0.06 

0.57 ± 0.09 

2.98 ± 0.42 

0.58 ± 0.24 

0.61 ± 0.11 

0.62 ± 0.10 

1.67 ± 0.17 

2.01 ± 0.23 

2.34 ± 0.40 

11.30 ± 1.18 

0.024 ± 0.012 

0.04 ± 0.02 

0.17 ± 0.03 

0.25 ± 0.07 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

5.17 ± 1.08 

0.11 ± 0.04 

0.30 ± 0.07 

0.07 ± 0.03 

0.38 ± 0.05 

0.22 ± 0.03 

0.000 ± 0.000 

0.000 ± 0.000 

5.76 ± 0.44 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.27 ± 0.17 

0.30 ± 0.06 

0.93 ± 0.16 

3.42 ± 0.31 

0.67 ± 0.10 

0.49 ± 0.10 

0.66 ± 0.10 

1.53 ± 0.15 

1.20 ± 0.14* 

2.76 ± 0.27 

9.22 ± 1.18 

0.057 ± 0.021 

0.05 ± 0.02 

0.17 ± 0.03 

0.24 ± 0.05 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

5.80 ± 1.12 

0.19 ± 0.05 

0.30 ± 0.06 

0.05 ± 0.02 

0.46 ± 0.13 

0.22 ± 0.04 

0.000 ± 0.000 

0.000 ± 0.000 

5.20 ± 0.49 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.41 ± 0.14 

0.27 ± 0.05 

0.80 ± 0.21 

3.34 ± 0.46 

0.62 ± 0.14 

0.51 ± 0.10 

0.69 ± 0.10 

1.65 ± 0.15 

1.44 ± 0.15 

3.08 ± 0.37 

11.23 ± 0.84 

0.070 ± 0.030 

0.09 ± 0.02 

0.13 ± 0.03 

0.23 ± 0.05 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

3.72 ± 0.38 

0.18 ± 0.04 

0.23 ± 0.04 

0.09 ± 0.04 

0.53 ± 0.08 

0.31 ± 0.06 

0.000 ± 0.000 

0.036 ± 0.036 

5.26 ± 0.47 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.15 ± 0.08 
AZT and AZT/"-Interferon A/D, NTP TR 469 271 

TABLE K4 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Female 

Hematology 

Clinical Pathology Groups 

n 

Week 14 9 9 10 10 

Week 27 9 10 10 10 

Week 40 9 10 10 9 

Week 54 8 9 10 10 

Week 65 9 10 10 9 

Week 79 10 10 9 9 

Hematocrit (%) 

Week 14 44.3 ± 0.8 44.5 ± 0.4 44.1 ± 0.3 44.3 ± 0.4 

Week 27 45.3 ± 0.4 44.2 ± 0.4 44.4 ± 0.4 44.5 ± 0.4 

Week 40 46.5 ± 0.5 45.2 ± 0.4 45.4 ± 0.4 43.6 ± 0.4** 

Week 54 48.8 ± 0.6 47.5 ± 0.3 46.6 ± 0.2** 47.0 ± 0.6* 

Week 65 46.2 ± 0.4 46.0 ± 0.4 44.9 ± 0.6 43.6 ± 0.5** 

Week 79 43.5 ± 0.6 42.9 ± 0.5 42.6 ± 0.6 41.2 ± 1.1 

Hemoglobin (g/dL) 

Week 14 15.0 ± 0.2 15.1 ± 0.1 14.8 ± 0.1 14.9 ± 0.1 

Week 27 15.1 ± 0.1 14.7 ± 0.1 14.6 ± 0.1 14.6 ± 0.1 

Week 40 15.6 ± 0.2 15.2 ± 0.1* 15.2 ± 0.1 14.7 ± 0.1** 

Week 54 16.4 ± 0.2 15.9 ± 0.1 15.5 ± 0.1** 15.5 ± 0.2** 

Week 65 15.5 ± 0.2 15.4 ± 0.2 14.9 ± 0.2* 14.6 ± 0.2** 

Week 79 14.7 ± 0.2 14.3 ± 0.2 14.3 ± 0.2 13.7 ± 0.4* 

Erythrocytes (10 /μL) 6 

Week 14 9.56 ± 0.17 9.31 ± 0.07* 9.00 ± 0.07** 8.92 ± 0.07** 

Week 27 9.78 ± 0.09 9.18 ± 0.09** 8.96 ± 0.11** 8.88 ± 0.11** 

Week 40 9.60 ± 0.12 8.98 ± 0.07** 8.87 ± 0.09** 8.40 ± 0.07** 

Week 54 9.76 ± 0.15 9.07 ± 0.06** 8.78 ± 0.09** 8.70 ± 0.10** 

Week 65 9.51 ± 0.09 8.86 ± 0.09** 8.60 ± 0.11** 8.17 ± 0.11** 

Week 79 9.25 ± 0.11 8.89 ± 0.16 8.61 ± 0.09** 8.07 ± 0.21** 

Reticulocytes (10 /μL) 6 

Week 14 0.22 ± 0.03 0.28 ± 0.02 0.31 ± 0.02* 0.32 ± 0.02* 

Week 27 0.29 ± 0.02 0.28 ± 0.02 0.30 ± 0.01 0.31 ± 0.01 

Week 40 0.27 ± 0.02 0.17 ± 0.02* 0.14 ± 0.01** 0.15 ± 0.01** 

Week 54 0.12 ± 0.01 0.13 ± 0.02 0.15 ± 0.02 0.11 ± 0.01 

Week 65 0.18 ± 0.03 0.13 ± 0.02 0.13 ± 0.02 0.15 ± 0.03 

Week 79 0.21 ± 0.02 0.18 ± 0.04b 0.26 ± 0.03 0.19 ± 0.03 

Nucleated erythrocytes (10 /μL) 3 

Week 14 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 27 0.00 ± 0.00 0.00 ± 0.00 0.01 ± 0.01 0.00 ± 0.00 

Week 40 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 54 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 65 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 79 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Mean cell volume (fL) 

Week 14 46.4 ± 0.3 47.8 ± 0.2** 49.1 ± 0.2** 49.7 ± 0.1** 

Week 27 46.4 ± 0.2 48.1 ± 0.2** 49.6 ± 0.3** 50.1 ± 0.3** 

Week 40 48.4 ± 0.2 50.3 ± 0.2** 51.1 ± 0.2** 51.9 ± 0.4** 

Week 54 50.0 ± 0.4 52.4 ± 0.2** 53.1 ± 0.3** 54.0 ± 0.3** 

Week 65 48.6 ± 0.3 51.9 ± 0.4** 52.3 ± 0.8** 53.3 ± 0.4** 

Week 79 47.0 ± 0.4 48.3 ± 0.7 49.5 ± 0.5** 51.1 ± 0.4** 
272 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K4 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Female (continued) 

Hematology (continued) 

Clinical Pathology Groups (continued) 

n 

Week 14 9 9 10 10 

Week 27 9 10 10 10 

Week 40 9 10 10 9 

Week 54 8 9 10 10 

Week 65 9 10 10 9 

Week 79 10 10 9 9 

Mean cell hemoglobin (pg) 

Week 14 15.7 ± 0.1 16.2 ± 0.1** 16.4 ± 0.1** 16.8 ± 0.1** 

Week 27 15.4 ± 0.1 16.0 ± 0.0** 16.3 ± 0.1** 16.4 ± 0.1** 

Week 40 16.2 ± 0.1 16.9 ± 0.1** 17.2 ± 0.1** 17.5 ± 0.1** 

Week 54 16.9 ± 0.1 17.5 ± 0.1** 17.7 ± 0.1** 17.8 ± 0.1** 

Week 65 16.3 ± 0.1 17.4 ± 0.1** 17.4 ± 0.3** 17.9 ± 0.1** 

Week 79 15.9 ± 0.1 16.1 ± 0.3 16.6 ± 0.2** 17.0 ± 0.1** 

Mean cell hemoglobin concentration (g/dL) 

Week 14 33.8 ± 0.2 33.8 ± 0.1 33.5 ± 0.1 33.7 ± 0.1 

Week 27 33.2 ± 0.1 33.2 ± 0.1 32.9 ± 0.2* 32.8 ± 0.1* 

Week 40 33.5 ± 0.2 33.6 ± 0.1 33.5 ± 0.1 33.7 ± 0.2 

Week 54 33.7 ± 0.2 33.4 ± 0.2 33.4 ± 0.1 33.0 ± 0.2* 

Week 65 33.6 ± 0.2 33.5 ± 0.1 33.2 ± 0.2 33.6 ± 0.2 

Week 79 33.7 ± 0.2 33.4 ± 0.2 33.6 ± 0.2 33.3 ± 0.2 

Platelets (10 /μL) 3 

Week 14 943.9 ± 40.6 978.8 ± 48.6 1,088.6 ± 43.3 1,082.3 ± 39.0 

Week 27 1,015.4 ± 36.6 1,138.2 ± 57.8 1,116.7 ± 42.1 1,181.4 ± 34.5* 

Week 40 1,035.7 ± 80.7 1,184.7 ± 72.0 1,196.3 ± 51.0 1,188.2 ± 70.9 

Week 54 1,056.8 ± 64.1 1,114.8 ± 46.8 1,144.6 ± 47.4 1,119.6 ± 54.2 

Week 65 1,202.1 ± 55.8 1,354.5 ± 48.9 1,208.3 ± 160.1 1,472.9 ± 60.9* 

Week 79 

Leukocytes (10 /μL) 3 1,177.8 ± 34.1 1,305.5 ± 68.9 1,281.3 ± 38.1 1,278.6 ± 66.4 

Week 14 6.59 ± 0.29 6.96 ± 0.29 6.28 ± 0.29 6.78 ± 0.43 

Week 27 6.30 ± 0.35 6.48 ± 0.28 5.97 ± 0.34 6.00 ± 0.58 

Week 40 6.46 ± 0.50 6.79 ± 0.36 6.26 ± 0.36 6.97 ± 0.63 

Week 54 5.66 ± 0.52 6.76 ± 0.27 5.13 ± 0.30 5.79 ± 0.37 

Week 65 5.34 ± 0.36 5.17 ± 0.43 5.62 ± 0.43 4.94 ± 0.47 

Week 79 4.76 ± 0.48 5.43 ± 0.45 4.83 ± 0.44 5.49 ± 0.46 

Segmented neutrophils (10 /μL) 3 

Week 14 0.97 ± 0.20 0.78 ± 0.08 0.81 ± 0.10 0.83 ± 0.11 

Week 27 0.97 ± 0.07 1.03 ± 0.07 1.13 ± 0.11 0.94 ± 0.11 

Week 40 1.38 ± 0.14 1.90 ± 0.44 1.12 ± 0.07 1.33 ± 0.09 

Week 54 1.05 ± 0.15 1.27 ± 0.17 0.99 ± 0.13 0.97 ± 0.17 

Week 65 1.05 ± 0.18 0.84 ± 0.13 1.06 ± 0.16 0.71 ± 0.11 

Week 79 1.18 ± 0.11 1.35 ± 0.19 0.88 ± 0.17 1.33 ± 0.21 

Lymphocytes (10 /μL) 3 

Week 14 5.56 ± 0.26 6.12 ± 0.28 5.37 ± 0.28 5.79 ± 0.36 

Week 27 5.15 ± 0.30 5.28 ± 0.26 4.70 ± 0.29 4.91 ± 0.52 

Week 40 4.70 ± 0.41 4.51 ± 0.42 4.78 ± 0.42 5.25 ± 0.59 

Week 54 4.42 ± 0.44 5.31 ± 0.30 3.95 ± 0.28 4.62 ± 0.25 

Week 65 4.11 ± 0.26 4.21 ± 0.37 4.44 ± 0.36 4.14 ± 0.42 

Week 79 3.31 ± 0.38 3.89 ± 0.34 3.76 ± 0.26 3.85 ± 0.44 
AZT and AZT/"-Interferon A/D, NTP TR 469 273 

TABLE K4 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Female (continued) 

Hematology (continued) 

Clinical Pathology Groups (continued) 

n 

Week 14 9 9 10 10 

Week 27 9 10 10 10 

Week 40 9 10 10 9 

Week 54 8 9 10 10 

Week 65 9 10 10 9 

Week 79 10 10 9 9 

Atypical lymphocytes (10 /μL) 3 

Week 14 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 27 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 40 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 54 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 65 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 79 0.01 ± 0.00 0.00 ± 0.00 0.01 ± 0.01 0.02 ± 0.01 

Monocytes (10 /μL) 3 

Week 14 0.00 ± 0.00 0.01 ± 0.01 0.01 ± 0.01 0.01 ± 0.01 

Week 27 0.04 ± 0.02 0.03 ± 0.01 0.04 ± 0.02 0.05 ± 0.02 

Week 40 0.22 ± 0.05 0.20 ± 0.04 0.17 ± 0.04 0.21 ± 0.06 

Week 54 0.13 ± 0.02 0.06 ± 0.03 0.08 ± 0.02 0.09 ± 0.04 

Week 65 0.07 ± 0.02 0.05 ± 0.01 0.06 ± 0.02 0.05 ± 0.02 

Week 79 0.12 ± 0.03 0.10 ± 0.02 0.11 ± 0.02 0.14 ± 0.01 

Eosinophils (10 /μL) 3 

Week 14 0.07 ± 0.02 0.05 ± 0.02 0.09 ± 0.03 0.14 ± 0.02 

Week 27 0.14 ± 0.02 0.13 ± 0.04 0.11 ± 0.02 0.10 ± 0.02 

Week 40 0.16 ± 0.04 0.17 ± 0.03 0.19 ± 0.03 0.18 ± 0.04 

Week 54 0.06 ± 0.03 0.11 ± 0.03 0.11 ± 0.04 0.12 ± 0.04 

Week 65 0.12 ± 0.04 0.07 ± 0.02 0.06 ± 0.02 0.04 ± 0.02 

Week 79 0.09 ± 0.02 0.07 ± 0.02 0.06 ± 0.01 0.10 ± 0.02 

Core Groups 

n 10 10 10 10 

Hematocrit (%) 47.4 ± 2.8 38.7 ± 2.0* 41.1 ± 2.2* 41.3 ± 1.3 

Hemoglobin (g/dL) 

Erythrocytes (10 /μL) 6 

Reticulocytes (10 /μL) 6 

Nucleated erythrocytes (10 /μL) 3 

15.8 ± 0.9 

10.36 ± 0.67 

0.68 ± 0.08 

0.00 ± 0.00 

12.9 ± 0.7* 

8.01 ± 0.44** 

0.66 ± 0.08 

0.00 ± 0.00 

13.5 ± 0.7* 

7.96 ± 0.53** 

0.79 ± 0.08 

0.00 ± 0.00 

13.6 ± 0.4* 

7.80 ± 0.36** 

0.90 ± 0.14 

0.01 ± 0.01 

Mean cell volume (fL) 45.9 ± 0.7 48.4 ± 0.3** 52.3 ± 1.3** 53.4 ± 1.1** 

Mean cell hemoglobin (pg) 15.3 ± 0.2 16.1 ± 0.1** 17.0 ± 0.3** 17.6 ± 0.3** 

Mean cell hemoglobin 

concentration (g/dL) 

Platelets (10 /μL) 3 

Leukocytes (10 /μL) 3 

Segmented neutrophils (10 /μL) 3 

Lymphocytes (10 /μL) 3 

Atypical lymphocytes (10 /μL) 3 

Monocytes (10 /μL) 3 

Eosinophils (10 /μL) 3 

33.4 ± 0.1 

1,229.7 ± 68.8 

7.00 ± 0.55 

1.88 ± 0.41 

4.47 ± 0.32 

0.33 ± 0.07 

0.22 ± 0.05 

0.09 ± 0.05 

33.4 ± 0.2 

1,534.7 ± 138.2 

7.53 ± 0.70 

1.62 ± 0.13 

5.39 ± 0.65 

0.26 ± 0.06 

0.19 ± 0.04 

0.08 ± 0.02 

32.7 ± 0.4 

1,316.2 ± 91.5 

8.39 ± 1.07 

2.32 ± 0.46 

5.47 ± 0.69 

0.35 ± 0.09 

0.21 ± 0.03 

0.04 ± 0.02 

33.0 ± 0.2 

1,203.3 ± 185.1 

5.86 ± 0.84 

1.77 ± 0.48 

3.72 ± 0.50 

0.18 ± 0.02 

0.13 ± 0.04 

0.07 ± 0.02 
274 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K4 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Female (continued) 

Bone Marrow Analyses 

Clinical Pathology Groups 

n 

Week 54 9 9 9 10 

Week 65 9 10 8 9 

Week 79 9 9 9 8 

Total femoral count (10 /femur) 6 

Week 54 27.0 ± 0.6 23.9 ± 1.0* 24.6 ± 0.7* 22.3 ± 0.9** 

Week 65 28.0 ± 1.0 28.8 ± 1.3 27.2 ± 1.0 28.5 ± 1.1 

Week 79 23.3 ± 1.7 24.1 ± 2.3 24.5 ± 1.9 26.1 ± 1.7 

M:E ratio 

Week 54 1.78 ± 0.14 1.89 ± 0.09 1.96 ± 0.19 2.39 ± 0.10** 

Week 65 1.91 ± 0.22 2.51 ± 0.19 1.83 ± 0.16 1.63 ± 0.18 

Week 79 1.48 ± 0.17 1.73 ± 0.17 1.53 ± 0.18 1.99 ± 0.24 

Rubriblasts (10 )

6 

Week 54 0.50 ± 0.06 0.28 ± 0.02** 0.35 ± 0.07** 0.26 ± 0.03** 

Week 65 0.32 ± 0.06 0.50 ± 0.07 0.35 ± 0.04 0.38 ± 0.06 

Week 79 0.29 ± 0.06 0.46 ± 0.09 0.44 ± 0.07 0.43 ± 0.07 

Prorubricytes (10 )

6 

Week 54 1.27 ± 0.12 1.33 ± 0.11 1.12 ± 0.23 1.05 ± 0.08 

Week 65 1.18 ± 0.22 1.15 ± 0.13 0.98 ± 0.15 1.61 ± 0.29 

Week 79 1.06 ± 0.09 1.26 ± 0.20 1.39 ± 0.20 1.37 ± 0.21 

Rubricytes (10 )

6 

Week 54 4.22 ± 0.44 3.95 ± 0.13 4.01 ± 0.26 2.97 ± 0.20** 

Week 65 4.40 ± 0.38 3.53 ± 0.44 4.64 ± 0.38 4.99 ± 0.45 

Week 79 4.38 ± 0.52 4.35 ± 0.59 4.67 ± 0.54 4.36 ± 0.47 

Metarubricytes (10 )

6 

Week 54 1.53 ± 0.09 0.70 ± 0.09** 0.83 ± 0.14** 0.69 ± 0.13** 

Week 65 0.87 ± 0.12 0.70 ± 0.10 0.92 ± 0.20 0.77 ± 0.12 

Week 79 1.17 ± 0.20 0.89 ± 0.15 0.91 ± 0.18 0.75 ± 0.11 

Myeloblasts (10 )

6 

Week 54 0.36 ± 0.03 0.33 ± 0.04 0.47 ± 0.04 0.43 ± 0.09 

Week 65 0.34 ± 0.03 0.35 ± 0.04 0.46 ± 0.08 0.46 ± 0.08 

Week 79 0.26 ± 0.04 0.30 ± 0.03 0.35 ± 0.10 0.41 ± 0.10 

Promyelocytes (10 )

6 

Week 54 0.75 ± 0.11 0.57 ± 0.05 0.50 ± 0.03 0.76 ± 0.10 

Week 65 0.60 ± 0.13 0.76 ± 0.10 0.60 ± 0.08 0.55 ± 0.13 

Week 79 0.32 ± 0.06 0.41 ± 0.11 0.35 ± 0.05 0.36 ± 0.03 

Neutrophilic myelocytes (10 )

6 

Week 54 0.86 ± 0.09 0.83 ± 0.09 0.90 ± 0.11 0.90 ± 0.15 

Week 65 0.84 ± 0.07 0.96 ± 0.12 1.05 ± 0.21 0.69 ± 0.12 

Week 79 0.73 ± 0.09 1.12 ± 0.18 1.01 ± 0.17 1.02 ± 0.11 

Neutrophilic metamyelocytes (10 )

6 

Week 54 0.98 ± 0.11 0.74 ± 0.09 0.94 ± 0.08 0.89 ± 0.17 

Week 65 1.54 ± 0.14 1.71 ± 0.17 2.15 ± 0.34 1.53 ± 0.19 

Week 79 1.26 ± 0.15 1.04 ± 0.14 1.18 ± 0.16 1.11 ± 0.17 

Neutrophilic bands (10 )

6 

Week 54 2.07 ± 0.24 1.17 ± 0.28* 1.22 ± 0.13* 1.91 ± 0.23 

Week 65 2.55 ± 0.28 3.11 ± 0.44 2.18 ± 0.19 2.37 ± 0.32 

Week 79 2.32 ± 0.37 3.12 ± 0.48 2.38 ± 0.30 3.75 ± 0.56 
AZT and AZT/"-Interferon A/D, NTP TR 469 275 

TABLE K4 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Female (continued) 

Bone Marrow Analyses (continued) 

Clinical Pathology Groups (continued) 

n 

Week 54 9 9 9 10 

Week 65 9 10 8 9 

Week 79 9 9 9 8 

Neutrophilic segments (10 )

6 

Week 54 7.38 ± 0.55 7.67 ± 0.60 6.71 ± 0.28 6.17 ± 0.65 

Week 65 5.40 ± 0.47 6.46 ± 0.34 5.22 ± 0.70 5.53 ± 0.31 

Week 79 4.14 ± 0.36 4.29 ± 0.66 4.82 ± 0.50 5.76 ± 0.81 

Eosinophilic myelocytes (10 )

6 

Week 54 0.068 ± 0.027 0.106 ± 0.025 0.120 ± 0.036 0.112 ± 0.019 

Week 65 0.103 ± 0.034 0.077 ± 0.018 0.079 ± 0.024 0.056 ± 0.023 

Week 79 0.007 ± 0.005 0.031 ± 0.012 0.016 ± 0.008 0.024 ± 0.009 

Eosinophilic metamyelocytes (10 )

6 

Week 54 0.11 ± 0.02 0.12 ± 0.03 0.17 ± 0.05 0.12 ± 0.03 

Week 65 0.16 ± 0.05 0.14 ± 0.03 0.12 ± 0.03 0.18 ± 0.05 

Week 79 0.07 ± 0.02 0.10 ± 0.02 0.09 ± 0.03 0.08 ± 0.03 

Eosinophilic bands (10 )

6 

Week 54 0.15 ± 0.02 0.12 ± 0.03 0.19 ± 0.04 0.19 ± 0.03 

Week 65 0.28 ± 0.05 0.21 ± 0.03 0.17 ± 0.06 0.25 ± 0.05 

Week 79 0.18 ± 0.03 0.35 ± 0.05* 0.20 ± 0.04 0.22 ± 0.04 

Eosinophilic segments (10 )

6 

Week 54 0.28 ± 0.03 0.21 ± 0.03 0.30 ± 0.06 0.34 ± 0.07 

Week 65 0.27 ± 0.05 0.37 ± 0.04 0.16 ± 0.03 0.39 ± 0.07 

Week 79 0.19 ± 0.02 0.27 ± 0.04 0.17 ± 0.03 0.18 ± 0.04 

Basophilic myelocytes (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 65 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic metamyelocytes (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 65 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic bands (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 65 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic segments (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 65 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Bone marrow lymphocytes (10 )

6 

Week 54 2.71 ± 0.17 2.02 ± 0.29 3.24 ± 0.26 2.52 ± 0.41 

Week 65 4.63 ± 0.40 4.30 ± 0.40 3.87 ± 0.43 4.15 ± 0.38 

Week 79 3.37 ± 0.35 2.83 ± 0.32 2.87 ± 0.25 2.46 ± 0.45 

Bone marrow macrophages (10 )

6 

Week 54 0.29 ± 0.04 0.18 ± 0.03 0.25 ± 0.04 0.13 ± 0.03** 

Week 65 0.09 ± 0.01 0.11 ± 0.03 0.09 ± 0.02 0.09 ± 0.03 

Week 79 0.15 ± 0.05 0.12 ± 0.02 0.12 ± 0.03 0.15 ± 0.04 
276 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K4 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Female (continued) 

Bone Marrow Analyses (continued) 

Clinical Pathology Groups (continued) 

n 

Week 54 9 9 9 10 

Week 65 9 10 8 9 

Week 79 9 9 9 8 

Bone marrow monocytes (10 )

6 

Week 54 0.28 ± 0.03 0.18 ± 0.02 0.18 ± 0.04 0.18 ± 0.03 

Week 65 0.17 ± 0.02 0.20 ± 0.05 0.13 ± 0.03 0.18 ± 0.03 

Week 79 0.28 ± 0.06 0.27 ± 0.05 0.26 ± 0.06 0.34 ± 0.10 

Megakaryo cells (10 )

6 

Week 54 0.10 ± 0.03 0.09 ± 0.02 0.07 ± 0.02 0.07 ± 0.02 

Week 65 0.06 ± 0.02 0.04 ± 0.02 0.03 ± 0.02 0.03 ± 0.02 

Week 79 0.05 ± 0.01 0.10 ± 0.03 0.06 ± 0.02 0.06 ± 0.02 

Plasma cells (10 )

6 

Week 54 0.41 ± 0.03 0.30 ± 0.06 0.35 ± 0.04 0.24 ± 0.06* 

Week 65 0.32 ± 0.11 0.22 ± 0.07 0.21 ± 0.06 0.22 ± 0.05 

Week 79 0.21 ± 0.03 0.23 ± 0.05 0.45 ± 0.13 0.35 ± 0.12 

Mitotic figures (10 )

6 

Week 54 0.21 ± 0.03 0.17 ± 0.02 0.15 ± 0.03 0.20 ± 0.04 

Week 65 0.31 ± 0.06 0.22 ± 0.02 0.19 ± 0.05 0.19 ± 0.03 

Week 79 0.28 ± 0.04 0.24 ± 0.05 0.33 ± 0.07 0.38 ± 0.07 

Fat cells (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 65 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Mast cells (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 65 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Smudge cells (10 )

6 

Week 54 2.44 ± 0.11 2.86 ± 0.29 2.55 ± 0.14 2.11 ± 0.13 

Week 65 3.55 ± 0.19 3.68 ± 0.37 3.55 ± 0.31 3.89 ± 0.37 

Week 79 2.58 ± 0.21 2.33 ± 0.34 2.41 ± 0.25 2.55 ± 0.22 

Osteoblasts (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 65 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Osteoclasts (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 65 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Other bone marrow cells (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 65 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Neutrophilic hypersegments (10 )

6 

Week 54 0.05 ± 0.03 0.05 ± 0.02 0.08 ± 0.03 0.04 ± 0.02 

Week 65 0.15 ± 0.06 0.35 ± 0.10 0.44 ± 0.09* 0.37 ± 0.04 

Week 79 0.26 ± 0.08 0.16 ± 0.04 0.36 ± 0.07 0.46 ± 0.15 
AZT and AZT/"-Interferon A/D, NTP TR 469 277 

TABLE K4 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/500 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 500 U "-IFN A/D 500 U "-IFN A/D 500 U "-IFN A/D 

Female (continued) 

Bone Marrow Analyses (continued) 

Core Groups 

n 9 9 10 10 

Total femoral count (10 /femur) 6 33.8 ± 2.6 33.2 ± 1.2 30.7 ± 2.1 30.5 ± 2.9 

M:E ratio 1.86 ± 0.15 2.38 ± 0.38 3.11 ± 0.47 4.76 ± 1.62 

Rubriblasts (10 )

6 

Prorubricytes (10 )

6 

Rubricytes (10 )

6 

Metarubricytes (10 )

6 

Myeloblasts (10 )

6 

Promyelocytes (10 )

6 

Neutrophilic myelocytes (10 )

6 

Neutrophilic metamyelocytes (10 )

6 

Neutrophilic bands (10 )

6 

Neutrophilic segments (10 )

6 

Eosinophilic myelocytes (10 )

6 

Eosinophilic metamyelocytes (10 )

6 

Eosinophilic bands (10 )

6 

Eosinophilic segments (10 )

6 

Basophilic myelocytes (10 )

6 

Basophilic metamyelocytes (10 )

6 

Basophilic bands (10 )

6 

Basophilic segments (10 )

6 

Bone marrow lymphocytes (10 )

6 

Bone marrow macrophages (10 )

6 

Bone marrow monocytes (10 )

6 

Megakaryo cells (10 )

6 

Plasma cells (10 )

6 

Mitotic figures (10 )

6 

Fat cells (10 )

6 

Mast cells (10 )

6 

Smudge cells (10 )

6 

Osteoblasts (10 )

6 

Osteoclasts (10 )

6 

Other bone marrow cells (10 )

6 

Neutrophilic hypersegments (10 )

6 

0.44 ± 0.09 

2.09 ± 0.42 

4.16 ± 0.46 

1.36 ± 0.26 

0.40 ± 0.06 

0.55 ± 0.11 

1.40 ± 0.31 

1.50 ± 0.21 

3.25 ± 0.33 

6.48 ± 0.58 

0.102 ± 0.029 

0.14 ± 0.04 

0.27 ± 0.07 

0.19 ± 0.06 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

5.33 ± 0.64 

0.18 ± 0.05 

0.24 ± 0.04 

0.14 ± 0.03 

0.35 ± 0.08 

0.34 ± 0.07 

0.000 ± 0.000 

0.000 ± 0.000 

4.84 ± 0.47 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.08 ± 0.05 

0.36 ± 0.08 

1.50 ± 0.23 

4.57 ± 0.66 

0.74 ± 0.12 

0.42 ± 0.06 

0.61 ± 0.08 

1.03 ± 0.11 

1.34 ± 0.13 

3.60 ± 0.41 

7.39 ± 0.61 

0.144 ± 0.028 

0.17 ± 0.03 

0.29 ± 0.07 

0.15 ± 0.04 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

4.76 ± 0.54 

0.14 ± 0.02 

0.23 ± 0.04 

0.13 ± 0.05 

0.60 ± 0.13 

0.33 ± 0.05 

0.000 ± 0.000 

0.000 ± 0.000 

4.67 ± 0.44 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.20 ± 0.08 

0.43 ± 0.06 

1.25 ± 0.23 

3.40 ± 0.61 

0.69 ± 0.16* 

0.35 ± 0.03 

0.61 ± 0.06 

1.29 ± 0.22 

1.67 ± 0.32 

3.67 ± 0.28 

6.90 ± 0.65 

0.079 ± 0.022 

0.16 ± 0.04 

0.19 ± 0.05 

0.16 ± 0.04 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

4.07 ± 0.45 

0.10 ± 0.01 

0.29 ± 0.11 

0.08 ± 0.02 

0.56 ± 0.09 

0.28 ± 0.05 

0.000 ± 0.000 

0.000 ± 0.000 

4.44 ± 0.25 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.37 ± 0.07 

0.35 ± 0.05 

0.79 ± 0.13** 

3.65 ± 0.65 

0.53 ± 0.14** 

0.40 ± 0.07 

0.60 ± 0.12 

1.32 ± 0.21 

1.62 ± 0.32 

3.92 ± 0.63 

8.10 ± 1.48 

0.089 ± 0.024 

0.15 ± 0.04 

0.29 ± 0.06 

0.17 ± 0.03 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

3.27 ± 0.66* 

0.15 ± 0.03 

0.28 ± 0.08 

0.07 ± 0.01 

0.62 ± 0.19 

0.31 ± 0.07 

0.000 ± 0.000 

0.000 ± 0.000 

3.87 ± 0.39 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.41 ± 0.14 

* Significantly different (P#0.05) from the control group by Dunn’s or Shirley’s test 

** P#0.01 a Mean ± standard error. Statistical tests were performed on unrounded data. b n=9 
278 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K5 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/Da 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Male 

Hematology 

Clinical Pathology Groups 

n 

Week 14 10 10 10 10 

Week 27 10 10 10 10 

Week 40 10 9 10 10 

Week 54 10 10 10 10 

Week 66 10 10 9 9 

Week 79 10 9 10 10 

Hematocrit (%) 

Week 14 48.9 ± 0.4 48.7 ± 0.5 47.4 ± 0.5 47.5 ± 0.8 

Week 27 46.3 ± 0.5 45.4 ± 0.5 45.7 ± 0.5 43.8 ± 0.3** 

Week 40 44.7 ± 0.8 43.5 ± 0.8 44.2 ± 0.4 41.2 ± 1.1 

Week 54 44.5 ± 0.9 45.7 ± 0.4 44.0 ± 0.5 42.4 ± 0.7 

Week 66 44.9 ± 0.8 42.7 ± 0.7 43.9 ± 0.5 45.1 ± 2.0 

Week 79 43.0 ± 1.0 42.5 ± 1.0 40.3 ± 1.4 41.2 ± 1.1 

Hemoglobin (g/dL) 

Week 14 16.4 ± 0.1 16.1 ± 0.2 15.8 ± 0.1** 15.8 ± 0.2* 

Week 27 15.3 ± 0.2 15.0 ± 0.2 15.2 ± 0.2 14.6 ± 0.1** 

Week 40 15.0 ± 0.3 14.6 ± 0.3 14.8 ± 0.1 13.8 ± 0.4* 

Week 54 14.6 ± 0.3 15.1 ± 0.2 14.5 ± 0.2 13.9 ± 0.3 

Week 66 15.1 ± 0.3 14.1 ± 0.2* 14.6 ± 0.2 14.9 ± 0.7 

Week 79 14.3 ± 0.3 13.9 ± 0.4 13.3 ± 0.5 13.5 ± 0.4 

Erythrocytes (10 /μL) 6 

Week 14 10.59 ± 0.10 10.21 ± 0.12* 9.78 ± 0.08** 9.58 ± 0.13** 

Week 27 10.19 ± 0.10 9.56 ± 0.12** 9.62 ± 0.12** 8.98 ± 0.07** 

Week 40 9.94 ± 0.11 9.38 ± 0.13** 9.32 ± 0.09** 8.50 ± 0.22** 

Week 54 9.53 ± 0.20 9.19 ± 0.15 8.90 ± 0.11* 8.24 ± 0.14** 

Week 66 9.48 ± 0.15 8.65 ± 0.13** 8.79 ± 0.11 8.98 ± 0.44* 

Week 79 8.96 ± 0.27 8.64 ± 0.34 7.83 ± 0.37* 7.95 ± 0.33* 

Reticulocytes (10 /μL) 6 

Week 14 0.24 ± 0.02b 0.26 ± 0.04b 0.25 ± 0.02c 0.27 ± 0.02b 

Week 27 0.21 ± 0.01 0.15 ± 0.01* 0.17 ± 0.01 0.19 ± 0.01 

Week 40 0.31 ± 0.02 0.22 ± 0.02 0.22 ± 0.02 0.24 ± 0.03 

Week 54 0.28 ± 0.02 0.22 ± 0.02 0.26 ± 0.02 0.27 ± 0.02 

Week 66 0.22 ± 0.02 0.22 ± 0.02 0.17 ± 0.01 0.20 ± 0.02 

Week 79 0.18 ± 0.03 0.18 ± 0.02 0.20 ± 0.03 0.20 ± 0.02 

Nucleated erythrocytes (10 /μL) 3 

Week 14 0.04 ± 0.01 0.01 ± 0.01 0.02 ± 0.01 0.02 ± 0.02 

Week 27 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.01 ± 0.01 

Week 40 0.01 ± 0.01 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 54 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 66 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 79 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Mean cell volume (fL) 

Week 14 46.2 ± 0.2 47.7 ± 0.4** 48.5 ± 0.3** 49.6 ± 0.3** 

Week 27 45.4 ± 0.2 47.5 ± 0.5** 47.5 ± 0.2** 48.8 ± 0.3** 

Week 40 45.0 ± 0.4 46.3 ± 0.6* 47.4 ± 0.7** 48.5 ± 0.6** 

Week 54 46.7 ± 0.6 49.8 ± 0.5** 49.5 ± 0.7** 51.5 ± 0.4** 

Week 66 47.4 ± 0.4 49.4 ± 0.5** 49.9 ± 0.6** 50.4 ± 0.5** 

Week 79 48.1 ± 0.6 49.4 ± 0.9 51.9 ± 1.1** 52.3 ± 1.3** 
AZT and AZT/"-Interferon A/D, NTP TR 469 279 

TABLE K5 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Male (continued) 

Hematology (continued) 

Clinical Pathology Groups (continued) 

n 

Week 14 10 10 10 10 

Week 27 10 10 10 10 

Week 40 10 9 10 10 

Week 54 10 10 10 10 

Week 66 10 10 9 9 

Week 79 10 9 10 10 

Mean cell hemoglobin (pg) 

Week 14 15.5 ± 0.1 15.7 ± 0.1 16.2 ± 0.1** 16.5 ± 0.1** 

Week 27 15.0 ± 0.1 15.7 ± 0.1** 15.9 ± 0.1** 16.3 ± 0.1** 

Week 40 15.1 ± 0.1 15.5 ± 0.2* 15.9 ± 0.2* 16.3 ± 0.2** 

Week 54 15.3 ± 0.2 16.5 ± 0.2** 16.3 ± 0.3** 16.9 ± 0.2** 

Week 66 16.0 ± 0.2 16.3 ± 0.1 16.6 ± 0.2 16.6 ± 0.2 

Week 79 16.0 ± 0.3 16.2 ± 0.2 17.1 ± 0.3* 17.1 ± 0.3* 

Mean cell hemoglobin concentration (g/dL) 

Week 14 33.6 ± 0.2 33.0 ± 0.2 33.4 ± 0.3 33.3 ± 0.2 

Week 27 33.1 ± 0.1 33.0 ± 0.2 33.4 ± 0.1 33.3 ± 0.1 

Week 40 33.6 ± 0.1 33.5 ± 0.2 33.5 ± 0.1 33.5 ± 0.1 

Week 54 32.8 ± 0.2 33.1 ± 0.1 32.9 ± 0.1 32.7 ± 0.2 

Week 66 33.7 ± 0.1 33.0 ± 0.2* 33.3 ± 0.1 33.1 ± 0.1 

Week 79 33.2 ± 0.2 32.8 ± 0.2 33.0 ± 0.2 32.7 ± 0.3 

Platelets (10 /μL) 3 

Week 14 1,005.2 ± 60.8 1,003.4 ± 36.4 1,008.1 ± 59.0 961.0 ± 24.5 

Week 27 1,096.0 ± 29.9 1,191.1 ± 33.5 1,195.8 ± 55.9 1,261.6 ± 45.7* 

Week 40 1,181.2 ± 37.3 1,448.6 ± 94.0* 1,229.2 ± 52.1 1,354.8 ± 63.3 

Week 54 1,274.7 ± 54.5 1,213.5 ± 57.1 1,503.1 ± 109.5 1,299.4 ± 57.7 

Week 66 1,207.5 ± 68.3 1,403.0 ± 53.8 1,416.6 ± 74.2 1,504.4 ± 60.7** 

Week 79 

Leukocytes (10 /μL) 3 1,524.9 ± 88.5 1,963.0 ± 129.4* 1,729.2 ± 75.3 1,785.5 ± 125.3 

Week 14 7.57 ± 0.34 7.53 ± 0.64 7.53 ± 0.32 6.99 ± 0.22 

Week 27 7.04 ± 0.44 7.24 ± 0.44 7.71 ± 0.25 7.34 ± 0.30 

Week 40 8.87 ± 0.71 8.87 ± 1.06 9.27 ± 0.61 8.47 ± 0.68 

Week 54 8.19 ± 0.63 7.51 ± 0.53 7.23 ± 0.42 7.54 ± 0.55 

Week 66 9.07 ± 0.72 9.46 ± 0.64 8.67 ± 1.04 8.88 ± 0.69 

Week 79 11.80 ± 1.12 11.30 ± 0.91 11.03 ± 1.23 10.78 ± 1.08 

Segmented neutrophils (10 /μL) 3 

Week 14 1.03 ± 0.16 1.09 ± 0.18 1.01 ± 0.12 0.82 ± 0.13 

Week 27 1.32 ± 0.15 1.47 ± 0.21 1.49 ± 0.17 1.37 ± 0.16 

Week 40 2.00 ± 0.23 2.07 ± 0.34 2.08 ± 0.34 1.95 ± 0.30 

Week 54 1.68 ± 0.16 1.51 ± 0.14 1.49 ± 0.11 1.66 ± 0.17 

Week 66 2.01 ± 0.23 2.12 ± 0.14 1.91 ± 0.25 1.78 ± 0.17 

Week 79 2.82 ± 0.30 2.79 ± 0.30 2.90 ± 0.47 2.92 ± 0.42 

Lymphocytes (10 /μL) 3 

Week 14 6.42 ± 0.26 6.23 ± 0.51 6.38 ± 0.25 5.98 ± 0.23 

Week 27 5.47 ± 0.37 5.54 ± 0.33 5.89 ± 0.28 5.66 ± 0.25 

Week 40 6.55 ± 0.56 6.56 ± 0.80 6.91 ± 0.34 6.21 ± 0.49 

Week 54 6.03 ± 0.50 5.61 ± 0.38 5.36 ± 0.32 5.45 ± 0.40 

Week 66 6.64 ± 0.51 6.80 ± 0.49 6.23 ± 0.75 6.65 ± 0.55 

Week 79 8.55 ± 0.86 8.02 ± 0.90 7.53 ± 1.04 7.53 ± 1.00 
280 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K5 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Male (continued) 

Hematology (continued) 

Clinical Pathology Groups (continued) 

n 

Week 14 10 10 10 10 

Week 27 10 10 10 10 

Week 40 10 9 10 10 

Week 54 10 10 10 10 

Week 66 10 10 9 9 

Week 79 10 9 10 10 

Atypical lymphocytes (10 /μL) 3 

Week 14 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 27 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 40 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 54 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 66 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 79 0.00 ± 0.00 0.00 ± 0.00 0.21 ± 0.21 0.00 ± 0.00 

Monocytes (10 /μL) 3 

Week 14 0.02 ± 0.01 0.03 ± 0.01 0.03 ± 0.01 0.01 ± 0.01 

Week 27 0.08 ± 0.03 0.05 ± 0.02 0.09 ± 0.04 0.09 ± 0.03 

Week 40 0.15 ± 0.04 0.11 ± 0.05 0.09 ± 0.04 0.06 ± 0.04 

Week 54 0.28 ± 0.03 0.19 ± 0.05 0.21 ± 0.03 0.26 ± 0.03 

Week 66 0.23 ± 0.05 0.33 ± 0.05 0.32 ± 0.07 0.34 ± 0.06 

Week 79 0.28 ± 0.07 0.31 ± 0.06 0.25 ± 0.05 0.26 ± 0.05 

Eosinophils (10 /μL) 3 

Week 14 0.10 ± 0.02 0.18 ± 0.03 0.10 ± 0.03 0.19 ± 0.03 

Week 27 0.17 ± 0.03 0.18 ± 0.04 0.23 ± 0.04 0.22 ± 0.04 

Week 40 0.18 ± 0.05 0.12 ± 0.04 0.19 ± 0.05 0.26 ± 0.06 

Week 54 0.19 ± 0.03 0.20 ± 0.03 0.17 ± 0.03 0.17 ± 0.02 

Week 66 0.20 ± 0.03 0.22 ± 0.03 0.21 ± 0.03 0.12 ± 0.02 

Week 79 0.13 ± 0.05 0.14 ± 0.05 0.13 ± 0.03 0.06 ± 0.03 

Core Groups 

n 10 10 10 10 

Hematocrit (%) 37.0 ± 3.6 36.8 ± 2.7 35.5 ± 2.1 33.0 ± 1.4 

Hemoglobin (g/dL) 

Erythrocytes (10 /μL) 6 

Reticulocytes (10 /μL) 6 

Nucleated erythrocytes (10 /μL) 3 

12.4 ± 1.2 

9.11 ± 1.02 

0.36 ± 0.03 

0.00 ± 0.00 

12.3 ± 0.8 

8.64 ± 0.64 

0.33 ± 0.03 

0.00 ± 0.00 

11.7 ± 0.8 

7.98 ± 0.56 

0.34 ± 0.03 

0.00 ± 0.00 

10.5 ± 0.5 

7.00 ± 0.38 

0.34 ± 0.02 

0.00 ± 0.00 

Mean cell volume (fL) 41.4 ± 1.0 42.7 ± 0.5 44.9 ± 1.1* 47.9 ± 2.2** 

Mean cell hemoglobin (pg) 13.8 ± 0.3 14.4 ± 0.2 14.7 ± 0.4 15.1 ± 0.3** 

Mean cell hemoglobin 

concentration (g/dL) 

Platelets (10 /μL) 3 

Leukocytes (10 /μL) 3 

Segmented neutrophils (10 /μL) 3 

Lymphocytes (10 /μL) 3 

Atypical lymphocytes (10 /μL) 3 

Monocytes (10 /μL) 3 

Eosinophils (10 /μL) 3 

33.4 ± 0.3 

1,507.0 ± 164.0 

18.21 ± 1.57 

5.52 ± 0.89 

10.34 ± 0.92 

1.78 ± 0.26 

0.39 ± 0.08 

0.18 ± 0.06 

33.6 ± 0.3 

1,783.1 ± 222.4 

16.44 ± 2.28 

4.92 ± 0.51 

9.58 ± 1.76 

1.28 ± 0.17 

0.48 ± 0.13 

0.19 ± 0.07 

32.8 ± 0.7 

2,312.5 ± 134.3** 

15.12 ± 1.52 

4.27 ± 0.39 

8.77 ± 1.24 

1.49 ± 0.28 

0.43 ± 0.07 

0.16 ± 0.06 

31.9 ± 0.9 

2,476.3 ± 157.4** 

16.70 ± 1.36 

4.56 ± 0.37 

10.11 ± 1.14 

1.56 ± 0.22 

0.38 ± 0.04 

0.10 ± 0.04 
AZT and AZT/"-Interferon A/D, NTP TR 469 281 

TABLE K5 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Male (continued) 

Bone Marrow Analyses 

Clinical Pathology Groups 

n 

Week 54 9 10 10 10 

Week 66 10 10 10 9 

Week 79 10 9 10 9 

Total femoral count (10 /femur) 6 

Week 54 28.3 ± 2.2 32.6 ± 1.6 30.3 ± 1.2 30.9 ± 0.9 

Week 66 31.1 ± 0.8 33.1 ± 1.3 29.7 ± 1.3 31.0 ± 0.9 

Week 79 38.1 ± 1.2 38.0 ± 1.5 36.4 ± 1.2 34.6 ± 1.1 

M:E ratio 

Week 54 1.92 ± 0.12 2.76 ± 0.24* 2.45 ± 0.15 2.72 ± 0.20* 

Week 66 2.82 ± 0.29 3.14 ± 0.39 3.83 ± 0.53 3.58 ± 0.69 

Week 79 2.88 ± 0.27 3.57 ± 0.55 4.60 ± 0.78 3.52 ± 0.37 

Rubriblasts (10 )

6 

Week 54 0.60 ± 0.10 0.57 ± 0.09 0.54 ± 0.06 0.48 ± 0.05 

Week 66 0.32 ± 0.04 0.37 ± 0.07 0.26 ± 0.04 0.25 ± 0.04 

Week 79 0.26 ± 0.03 0.28 ± 0.04 0.31 ± 0.04 0.29 ± 0.06 

Prorubricytes (10 )

6 

Week 54 0.41 ± 0.05 0.78 ± 0.09** 0.55 ± 0.08 0.50 ± 0.06 

Week 66 0.51 ± 0.10 0.71 ± 0.10 0.58 ± 0.09 0.59 ± 0.07 

Week 79 0.67 ± 0.09 0.94 ± 0.20 0.68 ± 0.11 0.68 ± 0.13 

Rubricytes (10 )

6 

Week 54 3.61 ± 0.28 3.54 ± 0.37 3.44 ± 0.18 3.47 ± 0.26 

Week 66 4.08 ± 0.42 3.90 ± 0.40 2.96 ± 0.46 3.70 ± 0.65 

Week 79 4.81 ± 0.32 4.09 ± 0.43 3.63 ± 0.64* 3.85 ± 0.34 

Metarubricytes (10 )

6 

Week 54 2.16 ± 0.17 1.45 ± 0.11* 1.76 ± 0.22 1.54 ± 0.12* 

Week 66 1.30 ± 0.17 1.12 ± 0.18 1.22 ± 0.28 0.98 ± 0.21 

Week 79 1.20 ± 0.18 0.52 ± 0.11** 0.72 ± 0.10 0.62 ± 0.12* 

Myeloblasts (10 )

6 

Week 54 0.39 ± 0.09 0.34 ± 0.06 0.33 ± 0.08 0.23 ± 0.05 

Week 66 0.42 ± 0.06 0.23 ± 0.04 0.36 ± 0.05 0.31 ± 0.04 

Week 79 0.49 ± 0.10 0.54 ± 0.08 0.58 ± 0.09 0.53 ± 0.06 

Promyelocytes (10 )

6 

Week 54 0.19 ± 0.05 0.26 ± 0.04 0.30 ± 0.04 0.21 ± 0.06 

Week 66 0.45 ± 0.06 0.41 ± 0.06 0.42 ± 0.05 0.46 ± 0.05 

Week 79 0.50 ± 0.07 0.60 ± 0.06 0.62 ± 0.12 0.68 ± 0.09 

Neutrophilic myelocytes (10 )

6 

Week 54 1.02 ± 0.13 1.28 ± 0.09 0.89 ± 0.07 0.63 ± 0.07* 

Week 66 0.86 ± 0.11 1.18 ± 0.19 0.87 ± 0.15 0.98 ± 0.11 

Week 79 1.33 ± 0.13 1.21 ± 0.09 1.57 ± 0.24 1.36 ± 0.17 

Neutrophilic metamyelocytes (10 )

6 

Week 54 2.97 ± 0.28 3.77 ± 0.39 3.14 ± 0.14 3.66 ± 0.28 

Week 66 1.72 ± 0.20 1.36 ± 0.22 1.65 ± 0.29 1.67 ± 0.19 

Week 79 2.55 ± 0.36 1.81 ± 0.21 1.75 ± 0.36 1.48 ± 0.19 

Neutrophilic bands (10 )

6 

Week 54 0.27 ± 0.04 0.34 ± 0.05 0.33 ± 0.06 0.35 ± 0.03 

Week 66 1.58 ± 0.13 1.89 ± 0.33 1.52 ± 0.27 1.98 ± 0.24 

Week 79 2.43 ± 0.32 2.17 ± 0.52 3.18 ± 0.53 1.82 ± 0.28 
282 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K5 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Male (continued) 

Bone Marrow Analyses (continued) 

Clinical Pathology Groups (continued) 

n 

Week 54 9 10 10 10 

Week 66 10 10 10 9 

Week 79 10 9 10 9 

Neutrophilic segments (10 )

6 

Week 54 7.71 ± 0.60 10.19 ± 0.68* 9.37 ± 0.43 10.33 ± 0.76* 

Week 66 10.90 ± 0.59 11.94 ± 1.00 11.02 ± 0.71 10.42 ± 0.73 

Week 79 11.42 ± 0.93 12.18 ± 1.52 12.18 ± 1.25 11.57 ± 0.82 

Eosinophilic myelocytes (10 )

6 

Week 54 0.020 ± 0.014 0.000 ± 0.000 0.022 ± 0.017 0.000 ± 0.000 

Week 66 0.025 ± 0.013 0.072 ± 0.020 0.029 ± 0.015 0.020 ± 0.015 

Week 79 0.028 ± 0.019 0.018 ± 0.018 0.031 ± 0.020 0.020 ± 0.014 

Eosinophilic metamyelocytes (10 )

6 

Week 54 0.15 ± 0.04 0.09 ± 0.03 0.14 ± 0.03 0.12 ± 0.03 

Week 66 0.03 ± 0.02 0.10 ± 0.03 0.06 ± 0.02 0.05 ± 0.02 

Week 79 0.08 ± 0.03 0.07 ± 0.04 0.07 ± 0.02 0.05 ± 0.03 

Eosinophilic bands (10 )

6 

Week 54 0.11 ± 0.04 0.10 ± 0.03 0.07 ± 0.02 0.12 ± 0.03 

Week 66 0.12 ± 0.02 0.11 ± 0.03 0.18 ± 0.03 0.22 ± 0.04 

Week 79 0.22 ± 0.08 0.17 ± 0.02 0.18 ± 0.02 0.25 ± 0.06 

Eosinophilic segments (10 )

6 

Week 54 0.20 ± 0.02 0.21 ± 0.05 0.30 ± 0.04 0.27 ± 0.04 

Week 66 0.33 ± 0.06 0.28 ± 0.07 0.29 ± 0.07 0.28 ± 0.07 

Week 79 0.27 ± 0.06 0.28 ± 0.05 0.35 ± 0.08 0.45 ± 0.07 

Basophilic myelocytes (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic metamyelocytes (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic bands (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic segments (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Bone marrow lymphocytes (10 )

6 

Week 54 3.71 ± 0.51 4.10 ± 0.32 4.10 ± 0.35 4.00 ± 0.16 

Week 66 3.04 ± 0.21 3.71 ± 0.33 3.13 ± 0.35 3.81 ± 0.44 

Week 79 5.52 ± 0.50 6.45 ± 0.87 4.71 ± 0.63 5.69 ± 0.69 

Bone marrow macrophages (10 )

6 

Week 54 0.24 ± 0.04 0.36 ± 0.05 0.34 ± 0.05 0.34 ± 0.04 

Week 66 0.08 ± 0.03 0.11 ± 0.03 0.18 ± 0.04 0.09 ± 0.02 

Week 79 0.11 ± 0.03 0.23 ± 0.07 0.15 ± 0.03 0.21 ± 0.05 
AZT and AZT/"-Interferon A/D, NTP TR 469 283 

TABLE K5 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Male (continued) 

Bone Marrow Analyses (continued) 

Clinical Pathology Groups (continued) 

n 

Week 54 9 10 10 10 

Week 66 10 10 10 9 

Week 79 10 9 10 9 

Bone marrow monocytes (10 )

6 

Week 54 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 66 0.22 ± 0.04 0.19 ± 0.02 0.33 ± 0.07 0.19 ± 0.05 

Week 79 0.28 ± 0.06 0.24 ± 0.04 0.33 ± 0.07 0.34 ± 0.07 

Megakaryo cells (10 )

6 

Week 54 0.10 ± 0.02 0.13 ± 0.02 0.08 ± 0.01 0.16 ± 0.04 

Week 66 0.05 ± 0.03 0.07 ± 0.02 0.09 ± 0.02 0.10 ± 0.03 

Week 79 0.12 ± 0.03 0.09 ± 0.02 0.11 ± 0.02 0.19 ± 0.08 

Plasma cells (10 )

6 

Week 54 0.14 ± 0.04 0.13 ± 0.03 0.10 ± 0.02 0.16 ± 0.05 

Week 66 0.16 ± 0.05 0.12 ± 0.02 0.22 ± 0.03* 0.30 ± 0.05* 

Week 79 0.38 ± 0.07 0.42 ± 0.11 0.31 ± 0.08 0.27 ± 0.10 

Mitotic figures (10 )

6 

Week 54 0.24 ± 0.04 0.27 ± 0.06 0.24 ± 0.04 0.26 ± 0.06 

Week 66 0.13 ± 0.03 0.12 ± 0.03 0.15 ± 0.03 0.16 ± 0.03 

Week 79 0.27 ± 0.04 0.16 ± 0.04 0.12 ± 0.04 0.19 ± 0.04 

Fat cells (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Mast cells (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Smudge cells (10 )

6 

Week 54 4.09 ± 0.61 4.64 ± 0.37 4.24 ± 0.25 4.03 ± 0.29 

Week 66 4.80 ± 0.25 5.14 ± 0.15 4.22 ± 0.50 4.43 ± 0.25 

Week 79 5.13 ± 0.42 5.47 ± 0.27 4.85 ± 0.29 4.15 ± 0.45 

Osteoblasts (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Osteoclasts (10 )

6 

Week 54 0.021 ± 0.015 0.037 ± 0.014 0.010 ± 0.007 0.044 ± 0.014 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Other bone marrow cells (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Neutrophilic hypersegments (10 )

6 

Week 54 0.09 ± 0.03 0.05 ± 0.02 0.17 ± 0.04 0.21 ± 0.04 

Week 66 0.02 ± 0.02 0.01 ± 0.01 0.02 ± 0.01 0.02 ± 0.01 

Week 79 0.13 ± 0.07 0.10 ± 0.04 0.07 ± 0.03 0.22 ± 0.11 
284 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K5 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Male (continued) 

Bone Marrow Analyses (continued) 

Core Groups 

n 10 10 10 10 

Total femoral count (10 /femur) 6 31.2 ± 1.3 31.5 ± 2.1 28.7 ± 3.0 28.1 ± 1.6 

M:E ratio 3.70 ± 0.47 4.55 ± 0.67 4.53 ± 0.77 4.37 ± 0.91 

Rubriblasts (10 )

6 

Prorubricytes (10 )

6 

Rubricytes (10 )

6 

Metarubricytes (10 )

6 

Myeloblasts (10 )

6 

Promyelocytes (10 )

6 

Neutrophilic myelocytes (10 )

6 

Neutrophilic metamyelocytes (10 )

6 

Neutrophilic bands (10 )

6 

Neutrophilic segments (10 )

6 

Eosinophilic myelocytes (10 )

6 

Eosinophilic metamyelocytes (10 )

6 

Eosinophilic bands (10 )

6 

Eosinophilic segments (10 )

6 

Basophilic myelocytes (10 )

6 

Basophilic metamyelocytes (10 )

6 

Basophilic bands (10 )

6 

Basophilic segments (10 )

6 

Bone marrow lymphocytes (10 )

6 

Bone marrow macrophages (10 )

6 

Bone marrow monocytes (10 )

6 

Megakaryo cells (10 )

6 

Plasma cells (10 )

6 

Mitotic figures (10 )

6 

Fat cells (10 )

6 

Mast cells (10 )

6 

Smudge cells (10 )

6 

Osteoblasts (10 )

6 

Osteoclasts (10 )

6 

Other bone marrow cells (10 )

6 

Neutrophilic hypersegments (10 )

6 

0.17 ± 0.05 

0.75 ± 0.12 

3.24 ± 0.31 

0.87 ± 0.18 

0.35 ± 0.06 

0.83 ± 0.11 

1.45 ± 0.21 

1.57 ± 0.16 

3.97 ± 0.45 

7.81 ± 0.66 

0.005 ± 0.005 

0.10 ± 0.03 

0.20 ± 0.04 

0.23 ± 0.03 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

3.89 ± 0.51 

0.12 ± 0.03 

0.20 ± 0.05 

0.04 ± 0.02 

0.58 ± 0.23 

0.23 ± 0.06 

0.000 ± 0.000 

0.000 ± 0.000 

4.56 ± 0.39 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

1.93 ± 0.27 

0.20 ± 0.05 

0.66 ± 0.14 

3.01 ± 0.44 

0.58 ± 0.11 

0.46 ± 0.08 

1.05 ± 0.16 

1.46 ± 0.22 

1.73 ± 0.23 

3.62 ± 0.56 

8.45 ± 0.86 

0.022 ± 0.012 

0.05 ± 0.02 

0.21 ± 0.04 

0.25 ± 0.03 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

4.68 ± 0.80 

0.12 ± 0.03 

0.15 ± 0.04 

0.09 ± 0.04 

0.43 ± 0.12 

0.22 ± 0.06 

0.000 ± 0.000 

0.000 ± 0.000 

4.08 ± 0.37 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

1.67 ± 0.27 

0.13 ± 0.03 

0.66 ± 0.12 

2.46 ± 0.41 

0.41 ± 0.10 

0.26 ± 0.03 

0.56 ± 0.05 

1.21 ± 0.18 

1.42 ± 0.29 

4.22 ± 0.81 

6.85 ± 0.81 

0.025 ± 0.019 

0.06 ± 0.02 

0.18 ± 0.03 

0.19 ± 0.03 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

5.06 ± 0.58 

0.11 ± 0.02 

0.23 ± 0.06 

0.03 ± 0.02 

0.50 ± 0.10 

0.20 ± 0.04 

0.000 ± 0.000 

0.000 ± 0.000 

3.92 ± 0.50 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

1.61 ± 0.44 

0.14 ± 0.03 

0.67 ± 0.14 

2.88 ± 0.49 

0.50 ± 0.07 

0.28 ± 0.04 

0.74 ± 0.10 

1.19 ± 0.18 

1.46 ± 0.16 

4.17 ± 0.51 

6.63 ± 0.68 

0.060 ± 0.029 

0.09 ± 0.02 

0.17 ± 0.05 

0.15 ± 0.04 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

3.82 ± 0.45 

0.08 ± 0.02 

0.19 ± 0.03 

0.07 ± 0.02 

0.62 ± 0.18 

0.25 ± 0.07 

0.000 ± 0.000 

0.000 ± 0.000 

3.87 ± 0.30 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

1.56 ± 0.33 
AZT and AZT/"-Interferon A/D, NTP TR 469 285 

TABLE K5 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Female 

Hematology 

Clinical Pathology Groups 

n 

Week 14 10 9 9 9 

Week 27 9 10 9 10 

Week 40 9 9 10 10 

Week 54 9 9 9 9 

Week 66 8 10 9 10 

Week 79 8 7 8 8 

Hematocrit (%) 

Week 14 46.0 ± 0.6 45.9 ± 0.5 45.2 ± 0.8 44.6 ± 0.5 

Week 27 45.6 ± 0.5 43.9 ± 0.4 43.9 ± 0.5 44.1 ± 0.5 

Week 40 45.8 ± 0.4 45.4 ± 0.5 44.8 ± 0.5 44.7 ± 0.4 

Week 54 46.7 ± 0.4 45.3 ± 0.4 45.1 ± 0.7** 44.9 ± 0.3** 

Week 66 46.2 ± 0.3 46.0 ± 0.3 45.1 ± 0.5 46.2 ± 0.6 

Week 79 49.3 ± 4.1 44.7 ± 0.5 43.4 ± 0.7 44.7 ± 0.6 

Hemoglobin (g/dL) 

Week 14 15.3 ± 0.2 15.3 ± 0.2 15.2 ± 0.2 14.8 ± 0.2 

Week 27 15.2 ± 0.2 14.7 ± 0.2 14.6 ± 0.1 14.7 ± 0.1 

Week 40 15.5 ± 0.1 15.3 ± 0.2 15.1 ± 0.1 15.0 ± 0.2 

Week 54 15.5 ± 0.1 15.0 ± 0.1* 14.7 ± 0.2** 14.8 ± 0.1** 

Week 66 15.6 ± 0.1 15.6 ± 0.1 15.0 ± 0.1 15.4 ± 0.2 

Week 79 16.7 ± 1.4 15.1 ± 0.2 14.6 ± 0.3 14.9 ± 0.3 

Erythrocytes (10 /μL) 6 

Week 14 10.27 ± 0.20 9.90 ± 0.14 9.64 ± 0.17* 9.29 ± 0.13** 

Week 27 9.72 ± 0.09 9.03 ± 0.08** 8.83 ± 0.09** 8.79 ± 0.06** 

Week 40 9.91 ± 0.09 9.40 ± 0.11** 9.09 ± 0.08** 8.86 ± 0.08** 

Week 54 9.75 ± 0.12 8.92 ± 0.06** 8.63 ± 0.12** 8.54 ± 0.07** 

Week 66 9.80 ± 0.09 9.19 ± 0.06** 8.83 ± 0.13** 8.99 ± 0.16** 

Week 79 10.15 ± 0.83 8.71 ± 0.08** 8.34 ± 0.14** 8.33 ± 0.11** 

Reticulocytes (10 /μL) 6 

Week 14 0.15 ± 0.03c 0.16 ± 0.02 0.17 ± 0.02d 0.14 ± 0.02d 

Week 27 0.25 ± 0.02 0.20 ± 0.02 0.20 ± 0.02 0.15 ± 0.02** 

Week 40 0.24 ± 0.02 0.15 ± 0.02* 0.16 ± 0.02* 0.10 ± 0.02** 

Week 54 0.32 ± 0.02 0.36 ± 0.02 0.32 ± 0.03 0.42 ± 0.03* 

Week 66 0.27 ± 0.04 0.22 ± 0.02 0.22 ± 0.03 0.24 ± 0.02 

Week 79 0.23 ± 0.03 0.18 ± 0.01 0.19 ± 0.02 0.19 ± 0.02 

Nucleated erythrocytes (10 /μL) 3 

Week 14 0.01 ± 0.01 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 27 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 40 0.00 ± 0.00 0.01 ± 0.01 0.01 ± 0.01 0.01 ± 0.01 

Week 54 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 66 0.01 ± 0.01 0.00 ± 0.00c 0.00 ± 0.00 0.00 ± 0.00 

Week 79 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Mean cell volume (fL) 

Week 14 44.9 ± 0.5 46.4 ± 0.4* 46.9 ± 0.4** 48.0 ± 0.3** 

Week 27 46.9 ± 0.3 48.6 ± 0.2** 49.7 ± 0.1** 50.1 ± 0.3** 

Week 40 46.2 ± 0.3 48.3 ± 0.2** 49.2 ± 0.3** 50.4 ± 0.2** 

Week 54 47.9 ± 0.5 50.8 ± 0.2** 52.2 ± 0.2** 52.6 ± 0.2** 

Week 66 47.2 ± 0.5 50.1 ± 0.3** 51.1 ± 0.4** 51.5 ± 0.4** 

Week 79 48.6 ± 0.3 51.3 ± 0.3** 52.2 ± 0.7** 53.6 ± 0.5** 
286 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K5 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Female (continued) 

Hematology (continued) 

Clinical Pathology Groups (continued) 

n 

Week 14 10 9 9 9 

Week 27 9 10 9 10 

Week 40 9 9 10 10 

Week 54 9 9 9 9 

Week 66 8 10 9 10 

Week 79 8 7 8 8 

Mean cell hemoglobin (pg) 

Week 14 15.0 ± 0.1 15.5 ± 0.1** 15.8 ± 0.1** 16.0 ± 0.2** 

Week 27 15.6 ± 0.1 16.3 ± 0.1** 16.6 ± 0.1** 16.7 ± 0.1** 

Week 40 15.6 ± 0.1 16.3 ± 0.0** 16.6 ± 0.1** 16.9 ± 0.1** 

Week 54 15.9 ± 0.1 16.8 ± 0.1** 17.1 ± 0.1** 17.4 ± 0.1** 

Week 66 15.9 ± 0.2 17.0 ± 0.1** 17.0 ± 0.1** 17.1 ± 0.2** 

Week 79 16.4 ± 0.1 17.3 ± 0.2** 17.5 ± 0.3** 17.8 ± 0.2** 

Mean cell hemoglobin concentration (g/dL) 

Week 14 33.3 ± 0.2 33.4 ± 0.2 33.6 ± 0.2 33.4 ± 0.3 

Week 27 33.4 ± 0.1 33.5 ± 0.2 33.3 ± 0.2 33.3 ± 0.1 

Week 40 33.9 ± 0.2 33.8 ± 0.2 33.8 ± 0.2 33.6 ± 0.2 

Week 54 33.1 ± 0.3 33.2 ± 0.2 32.7 ± 0.2 33.0 ± 0.2 

Week 66 33.8 ± 0.2 33.9 ± 0.1 33.3 ± 0.1 33.2 ± 0.2 

Week 79 33.7 ± 0.2 33.8 ± 0.2 33.5 ± 0.2 33.2 ± 0.2 

Platelets (10 /μL) 3 

Week 14 979.9 ± 57.4 810.9 ± 61.3 915.1 ± 75.4 956.3 ± 47.7 

Week 27 953.6 ± 37.9 1,080.5 ± 52.7 1,060.4 ± 48.1 1,094.0 ± 60.8 

Week 40 1,074.8 ± 51.0 1,153.4 ± 33.4 1,146.4 ± 43.7 1,158.9 ± 62.7 

Week 54 1,053.0 ± 41.0 1,039.8 ± 55.5 1,180.9 ± 71.1 1,211.4 ± 65.5 

Week 66 1,016.3 ± 50.5 945.6 ± 45.3 1,180.0 ± 39.8 1,122.0 ± 56.6 

Week 79 

Leukocytes (10 /μL) 3 1,115.0 ± 92.0 1,357.4 ± 75.1 1,352.3 ± 108.3 1,342.6 ± 74.7 

Week 14 6.78 ± 0.34 5.89 ± 0.35 5.70 ± 0.25 6.50 ± 0.66 

Week 27 6.79 ± 0.47 6.35 ± 0.35 5.78 ± 0.23 6.18 ± 0.32 

Week 40 6.15 ± 0.34 6.24 ± 0.44 6.52 ± 0.33 5.08 ± 0.37 

Week 54 4.87 ± 0.32 4.62 ± 0.26 4.38 ± 0.21 5.18 ± 0.25 

Week 66 4.69 ± 0.33 4.87 ± 0.35c 4.44 ± 0.39 4.41 ± 0.20 

Week 79 4.02 ± 0.18 5.45 ± 0.31* 4.83 ± 0.45 4.81 ± 0.31 

Segmented neutrophils (10 /μL) 3 

Week 14 1.12 ± 0.10 0.85 ± 0.13 0.88 ± 0.11 1.22 ± 0.35 

Week 27 0.96 ± 0.10 0.97 ± 0.06 1.02 ± 0.10 0.91 ± 0.10 

Week 40 1.05 ± 0.12 1.28 ± 0.15 1.11 ± 0.12 0.86 ± 0.09 

Week 54 0.91 ± 0.08 0.99 ± 0.11 0.98 ± 0.13 0.86 ± 0.07 

Week 66 1.25 ± 0.27 1.06 ± 0.09c 0.96 ± 0.13 0.95 ± 0.08 

Week 79 1.22 ± 0.19 1.10 ± 0.05 1.16 ± 0.13 0.99 ± 0.10 

Lymphocytes (10 /μL) 3 

Week 14 5.38 ± 0.30 4.80 ± 0.31 4.59 ± 0.26 5.00 ± 0.56 

Week 27 5.70 ± 0.44 5.13 ± 0.31 4.56 ± 0.17* 5.08 ± 0.27 

Week 40 4.95 ± 0.30 4.75 ± 0.28 5.26 ± 0.28 4.04 ± 0.32 

Week 54 3.68 ± 0.29 3.16 ± 0.17 3.08 ± 0.19 3.96 ± 0.22 

Week 66 3.10 ± 0.45 3.48 ± 0.28c 3.11 ± 0.31 3.19 ± 0.15 

Week 79 2.62 ± 0.20 3.85 ± 0.46* 3.40 ± 0.38 3.59 ± 0.20* 
AZT and AZT/"-Interferon A/D, NTP TR 469 287 

TABLE K5 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Female (continued) 

Hematology (continued) 

Clinical Pathology Groups (continued) 

n 

Week 14 10 9 9 9 

Week 27 9 10 9 10 

Week 40 9 9 10 10 

Week 54 9 9 9 9 

Week 66 8 10 9 10 

Week 79 8 7 8 8 

Atypical lymphocytes (10 /μL) 3 

Week 14 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 27 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 40 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 54 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 66 0.00 ± 0.00 0.00 ± 0.00c 0.00 ± 0.00 0.00 ± 0.00 

Week 79 0.00 ± 0.00 0.19 ± 0.19 0.00 ± 0.00 0.00 ± 0.00 

Monocytes (10 /μL) 3 

Week 14 0.10 ± 0.04 0.08 ± 0.03 0.06 ± 0.02 0.07 ± 0.04 

Week 27 0.00 ± 0.00 0.02 ± 0.02 0.01 ± 0.01 0.01 ± 0.01 

Week 40 0.03 ± 0.02 0.00 ± 0.00 0.04 ± 0.02 0.01 ± 0.01 

Week 54 0.19 ± 0.05 0.20 ± 0.06 0.14 ± 0.03 0.20 ± 0.05 

Week 66 0.19 ± 0.03 0.17 ± 0.01c 0.17 ± 0.03 0.13 ± 0.01 

Week 79 0.11 ± 0.01 0.09 ± 0.03 0.14 ± 0.02 0.11 ± 0.03 

Eosinophils (10 /μL) 3 

Week 14 0.18 ± 0.04 0.16 ± 0.04 0.16 ± 0.04 0.21 ± 0.04 

Week 27 0.13 ± 0.03 0.22 ± 0.05 0.18 ± 0.05 0.18 ± 0.04 

Week 40 0.13 ± 0.03 0.20 ± 0.06 0.12 ± 0.03 0.17 ± 0.05 

Week 54 0.09 ± 0.03 0.27 ± 0.06* 0.18 ± 0.04 0.16 ± 0.03 

Week 66 0.14 ± 0.03 0.16 ± 0.04c 0.20 ± 0.03 0.13 ± 0.02 

Week 79 0.07 ± 0.02 0.21 ± 0.05* 0.13 ± 0.02 0.12 ± 0.01 

Core Groups 

n 10 9 10 10 

Hematocrit (%) 42.6 ± 3.2 46.8 ± 3.4 40.6 ± 0.6 40.1 ± 0.4 

Hemoglobin (g/dL) 

Erythrocytes (10 /μL) 6 

Reticulocytes (10 /μL) 6 

Nucleated erythrocytes (10 /μL) 3 

13.0 ± 0.9 

9.42 ± 0.83 

0.22 ± 0.02 

0.00 ± 0.00 

14.6 ± 0.9 

9.85 ± 0.67 

0.25 ± 0.02 

0.00 ± 0.00 

12.5 ± 0.2 

8.19 ± 0.17 

0.13 ± 0.02* 

0.00 ± 0.00 

12.2 ± 0.2 

7.95 ± 0.10* 

0.12 ± 0.02* 

0.00 ± 0.00 

Mean cell volume (fL) 45.7 ± 1.3 47.5 ± 0.6 49.7 ± 0.7** 50.5 ± 0.6** 

Mean cell hemoglobin (pg) 14.0 ± 0.3 14.9 ± 0.3* 15.3 ± 0.2** 15.3 ± 0.2** 

Mean cell hemoglobin 

concentration (g/dL) 

Platelets (10 /μL) 3 

Leukocytes (10 /μL) 3 

Segmented neutrophils (10 /μL) 3 

Lymphocytes (10 /μL) 3 

Atypical lymphocytes (10 /μL) 3 

Monocytes (10 /μL) 3 

Eosinophils (10 /μL) 3 

30.7 ± 0.3 

1,130.0 ± 130.3 

8.48 ± 0.97 

2.60 ± 0.37 

5.48 ± 0.78 

0.00 ± 0.00 

0.29 ± 0.05 

0.11 ± 0.04 

31.4 ± 0.8 

1,220.2 ± 149.6 

8.12 ± 0.94 

3.04 ± 0.50 

4.71 ± 0.63 

0.00 ± 0.00 

0.23 ± 0.04 

0.15 ± 0.05 

30.8 ± 0.2 

1,645.9 ± 67.1** 

8.38 ± 1.14 

3.20 ± 0.91 

4.70 ± 0.71 

0.00 ± 0.00 

0.29 ± 0.05 

0.20 ± 0.04 

30.3 ± 0.2 

1,599.9 ± 72.9** 

7.02 ± 0.65 

2.22 ± 0.28 

4.41 ± 0.50 

0.00 ± 0.00 

0.24 ± 0.03 

0.15 ± 0.04 
288 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K5 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Female (continued) 

Bone Marrow Analyses 

Clinical Pathology Groups 

n 

Week 54 9 9 9 9 

Week 66 8 10 8 9 

Week 79 9 7 9 9 

Total femoral count (10 /femur) 6 

Week 54 26.7 ± 1.5 27.2 ± 2.2 26.6 ± 1.4 27.5 ± 2.2 

Week 66 28.9 ± 1.6 28.2 ± 0.7 28.6 ± 0.8 26.8 ± 1.0 

Week 79 33.3 ± 2.1 30.8 ± 1.5 30.1 ± 0.9 30.1 ± 0.9 

M:E ratio 

Week 54 1.86 ± 0.09 2.04 ± 0.08 1.81 ± 0.11 2.08 ± 0.15 

Week 66 1.95 ± 0.16 1.94 ± 0.14 2.45 ± 0.35 2.43 ± 0.12* 

Week 79 2.24 ± 0.30 2.31 ± 0.23 2.57 ± 0.23 3.04 ± 0.24 

Rubriblasts (10 )

6 

Week 54 0.78 ± 0.12 0.69 ± 0.09 0.80 ± 0.06 0.51 ± 0.07 

Week 66 0.34 ± 0.06 0.37 ± 0.05 0.47 ± 0.05 0.28 ± 0.03 

Week 79 0.31 ± 0.03 0.31 ± 0.04 0.32 ± 0.04 0.39 ± 0.06 

Prorubricytes (10 )

6 

Week 54 0.57 ± 0.10 0.55 ± 0.09 0.65 ± 0.08 0.49 ± 0.08 

Week 66 0.26 ± 0.05 0.47 ± 0.07 0.42 ± 0.07 0.41 ± 0.06 

Week 79 1.13 ± 0.19 1.07 ± 0.17 0.89 ± 0.12 0.91 ± 0.16 

Rubricytes (10 )

6 

Week 54 3.61 ± 0.19 3.63 ± 0.39 3.81 ± 0.27 3.59 ± 0.34 

Week 66 4.21 ± 0.50 4.30 ± 0.21 4.28 ± 0.42 3.58 ± 0.29 

Week 79 4.75 ± 0.47 4.27 ± 0.25 3.85 ± 0.34 3.21 ± 0.23** 

Metarubricytes (10 )

6 

Week 54 1.80 ± 0.18 1.60 ± 0.13 1.72 ± 0.12 1.92 ± 0.16 

Week 66 1.59 ± 0.15 1.34 ± 0.12 0.92 ± 0.13** 0.96 ± 0.09** 

Week 79 0.97 ± 0.15 0.85 ± 0.16 0.91 ± 0.27 0.58 ± 0.09 

Myeloblasts (10 )

6 

Week 54 0.34 ± 0.03 0.37 ± 0.04 0.30 ± 0.04 0.33 ± 0.11 

Week 66 0.44 ± 0.09 0.40 ± 0.05 0.33 ± 0.04 0.40 ± 0.06 

Week 79 0.46 ± 0.08 0.46 ± 0.07 0.50 ± 0.06 0.53 ± 0.09 

Promyelocytes (10 )

6 

Week 54 0.28 ± 0.04 0.18 ± 0.05 0.20 ± 0.06 0.24 ± 0.06 

Week 66 0.30 ± 0.05 0.26 ± 0.07 0.32 ± 0.07 0.53 ± 0.19 

Week 79 0.50 ± 0.09 0.58 ± 0.09 0.61 ± 0.09 0.68 ± 0.23 

Neutrophilic myelocytes (10 )

6 

Week 54 0.94 ± 0.07 0.99 ± 0.14 0.60 ± 0.09 0.92 ± 0.12 

Week 66 1.00 ± 0.09 0.69 ± 0.09 0.75 ± 0.06 1.68 ± 0.42 

Week 79 1.37 ± 0.26 1.38 ± 0.17 1.16 ± 0.18 1.64 ± 0.29 

Neutrophilic metamyelocytes (10 )

6 

Week 54 3.22 ± 0.19 3.39 ± 0.45 2.61 ± 0.12 3.36 ± 0.42 

Week 66 2.78 ± 0.21 2.58 ± 0.15 3.17 ± 0.26 1.62 ± 0.33 

Week 79 1.66 ± 0.40 1.01 ± 0.17 0.99 ± 0.08 1.26 ± 0.16 

Neutrophilic bands (10 )

6 

Week 54 0.25 ± 0.04 0.29 ± 0.10 0.20 ± 0.03 0.24 ± 0.04 

Week 66 0.18 ± 0.04 0.28 ± 0.03 0.39 ± 0.09* 0.57 ± 0.11** 

Week 79 2.20 ± 0.23 2.58 ± 0.43 2.44 ± 0.30 2.29 ± 0.27 
AZT and AZT/"-Interferon A/D, NTP TR 469 289 

TABLE K5 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Female (continued) 

Bone Marrow Analyses (continued) 

Clinical Pathology Groups (continued) 

n 

Week 54 9 9 9 9 

Week 66 8 10 8 9 

Week 79 9 7 9 9 

Neutrophilic segments (10 )

6 

Week 54 6.63 ± 0.41 7.01 ± 0.56 7.77 ± 0.61 7.53 ± 0.97 

Week 66 6.59 ± 0.59 7.67 ± 0.48 8.11 ± 0.24 7.04 ± 0.50 

Week 79 8.00 ± 0.66 7.84 ± 0.61 7.84 ± 0.26 8.09 ± 0.48 

Eosinophilic myelocytes (10 )

6 

Week 54 0.054 ± 0.021 0.051 ± 0.017 0.033 ± 0.012 0.039 ± 0.021 

Week 66 0.015 ± 0.010 0.028 ± 0.013 0.050 ± 0.016 0.080 ± 0.037 

Week 79 0.026 ± 0.013 0.196 ± 0.050* 0.143 ± 0.046 0.081 ± 0.034 

Eosinophilic metamyelocytes (10 )

6 

Week 54 0.22 ± 0.04 0.36 ± 0.06 0.33 ± 0.06 0.34 ± 0.05 

Week 66 0.20 ± 0.05 0.12 ± 0.03 0.23 ± 0.04 0.10 ± 0.03 

Week 79 0.12 ± 0.02 0.20 ± 0.05 0.10 ± 0.03 0.11 ± 0.03 

Eosinophilic bands (10 )

6 

Week 54 0.14 ± 0.07 0.16 ± 0.06 0.12 ± 0.04 0.17 ± 0.03 

Week 66 0.11 ± 0.04 0.12 ± 0.04 0.18 ± 0.03 0.18 ± 0.05 

Week 79 0.17 ± 0.04 0.14 ± 0.04 0.26 ± 0.04 0.24 ± 0.04 

Eosinophilic segments (10 )

6 

Week 54 0.25 ± 0.06 0.33 ± 0.04 0.35 ± 0.05 0.34 ± 0.06 

Week 66 0.32 ± 0.08 0.22 ± 0.07 0.34 ± 0.01 0.37 ± 0.05 

Week 79 0.27 ± 0.05 0.29 ± 0.08 0.35 ± 0.08 0.23 ± 0.06 

Basophilic myelocytes (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic metamyelocytes (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic bands (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Basophilic segments (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Bone marrow lymphocytes (10 )

6 

Week 54 3.78 ± 0.34 3.55 ± 0.23 3.27 ± 0.33 4.05 ± 0.42 

Week 66 4.63 ± 0.55 4.57 ± 0.77 4.04 ± 0.38 4.63 ± 0.63 

Week 79 5.10 ± 1.08 4.37 ± 0.77 4.40 ± 0.33 4.62 ± 0.54 

Bone marrow macrophages (10 )

6 

Week 54 0.16 ± 0.02 0.23 ± 0.08 0.18 ± 0.04 0.21 ± 0.04 

Week 66 0.16 ± 0.01 0.14 ± 0.03 0.07 ± 0.02 0.13 ± 0.04 

Week 79 0.14 ± 0.02 0.19 ± 0.06 0.13 ± 0.02 0.14 ± 0.05 
290 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE K5 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Female (continued) 

Bone Marrow Analyses (continued) 

Clinical Pathology Groups (continued) 

n 

Week 54 9 9 9 9 

Week 66 8 10 8 9 

Week 79 9 7 9 9 

Bone marrow monocytes (10 )

6 

Week 54 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 66 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 0.00 ± 0.00 

Week 79 0.37 ± 0.12 0.16 ± 0.06 0.25 ± 0.04 0.22 ± 0.05 

Megakaryo cells (10 )

6 

Week 54 0.09 ± 0.02 0.13 ± 0.02 0.12 ± 0.03 0.06 ± 0.02 

Week 66 0.07 ± 0.02 0.11 ± 0.02 0.15 ± 0.03 0.10 ± 0.02 

Week 79 0.07 ± 0.02 0.08 ± 0.04 0.08 ± 0.02 0.09 ± 0.02 

Plasma cells (10 )

6 

Week 54 0.20 ± 0.03 0.21 ± 0.06 0.18 ± 0.04 0.24 ± 0.06 

Week 66 0.24 ± 0.04 0.22 ± 0.04 0.21 ± 0.02 0.17 ± 0.04 

Week 79 0.22 ± 0.05 0.31 ± 0.06 0.30 ± 0.04 0.26 ± 0.06 

Mitotic figures (10 )

6 

Week 54 0.23 ± 0.06 0.23 ± 0.04 0.27 ± 0.04 0.29 ± 0.03 

Week 66 0.21 ± 0.04 0.13 ± 0.03 0.28 ± 0.05 0.17 ± 0.04 

Week 79 0.31 ± 0.06 0.26 ± 0.05 0.22 ± 0.04 0.23 ± 0.03 

Fat cells (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Mast cells (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.046 ± 0.046 0.000 ± 0.000 0.000 ± 0.000 

Smudge cells (10 )

6 

Week 54 3.21 ± 0.55 3.28 ± 0.52 3.03 ± 0.43 2.66 ± 0.31 

Week 66 5.25 ± 0.37 4.15 ± 0.26* 3.82 ± 0.25** 3.71 ± 0.33** 

Week 79 5.16 ± 0.32 4.18 ± 0.47 4.38 ± 0.30 4.29 ± 0.22 

Osteoblasts (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Osteoclasts (10 )

6 

Week 54 0.008 ± 0.008 0.012 ± 0.008 0.006 ± 0.006 0.006 ± 0.006 

Week 66 0.038 ± 0.015 0.033 ± 0.013 0.035 ± 0.020 0.017 ± 0.008 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Other bone marrow cells (10 )

6 

Week 54 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 66 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Week 79 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 0.000 ± 0.000 

Neutrophilic hypersegments (10 )

6 

Week 54 0.19 ± 0.04 0.28 ± 0.05 0.21 ± 0.08 0.31 ± 0.08 

Week 66 0.06 ± 0.03 0.06 ± 0.03 0.08 ± 0.04 0.02 ± 0.02 

Week 79 0.08 ± 0.06 0.14 ± 0.04 0.10 ± 0.05 0.08 ± 0.04 
AZT and AZT/"-Interferon A/D, NTP TR 469 291 

TABLE K5 

Hematology and Bone Marrow Data for Mice in the 2-Year Gavage Study of AZT/5,000 U "-Interferon A/D 

30 mg AZT/kg + 60 mg AZT/kg + 120 mg AZT/kg + 

Vehicle Control 5,000 U "-IFN A/D 5,000 U "-IFN A/D 5,000 U "-IFN A/D 

Female (continued) 

Bone Marrow Analyses (continued) 

Core Groups 

n 10 10 9 10 

Total femoral count (10 /femur) 6 29.6 ± 2.4 29.9 ± 2.4 22.9 ± 1.7 24.4 ± 1.7 

M:E ratio 2.78 ± 0.39 2.76 ± 0.22 5.06 ± 0.57** 6.26 ± 0.73** 

Rubriblasts (10 )

6 

Prorubricytes (10 )

6 

Rubricytes (10 )

6 

Metarubricytes (10 )

6 

Myeloblasts (10 )

6 

Promyelocytes (10 )

6 

Neutrophilic myelocytes (10 )

6 

Neutrophilic metamyelocytes (10 )

6 

Neutrophilic bands (10 )

6 

Neutrophilic segments (10 )

6 

Eosinophilic myelocytes (10 )

6 

Eosinophilic metamyelocytes (10 )

6 

Eosinophilic bands (10 )

6 

Eosinophilic segments (10 )

6 

Basophilic myelocytes (10 )

6 

Basophilic metamyelocytes (10 )

6 

Basophilic bands (10 )

6 

Basophilic segments (10 )

6 

Bone marrow lymphocytes (10 )

6 

Bone marrow macrophages (10 )

6 

Bone marrow monocytes (10 )

6 

Megakaryo cells (10 )

6 

Plasma cells (10 )

6 

Mitotic figures (10 )

6 

Fat cells (10 )

6 

Mast cells (10 )

6 

Smudge cells (10 )

6 

Osteoblasts (10 )

6 

Osteoclasts (10 )

6 

Other bone marrow cells (10 )

6 

Neutrophilic hypersegments (10 )

6 

0.23 ± 0.06 

0.94 ± 0.16 

3.59 ± 0.41 

1.07 ± 0.20 

0.45 ± 0.09 

0.65 ± 0.08 

1.53 ± 0.22 

1.67 ± 0.17 

3.24 ± 0.38 

6.45 ± 0.52 

0.055 ± 0.025 

0.10 ± 0.04 

0.21 ± 0.04 

0.08 ± 0.03 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

4.14 ± 0.82 

0.08 ± 0.02 

0.17 ± 0.05 

0.06 ± 0.02 

0.30 ± 0.06 

0.31 ± 0.06 

0.000 ± 0.000 

0.000 ± 0.000 

4.33 ± 0.73 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

1.25 ± 0.19 

0.17 ± 0.04 

0.96 ± 0.21 

3.32 ± 0.37 

0.86 ± 0.10 

0.58 ± 0.12 

0.78 ± 0.10 

1.69 ± 0.14 

1.93 ± 0.25 

2.61 ± 0.25 

6.01 ± 0.88 

0.028 ± 0.013 

0.12 ± 0.03 

0.26 ± 0.04 

0.15 ± 0.03 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

5.28 ± 0.83 

0.12 ± 0.02 

0.25 ± 0.05 

0.07 ± 0.02 

0.50 ± 0.10 

0.26 ± 0.05 

0.000 ± 0.000 

0.000 ± 0.000 

3.95 ± 0.40 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

1.30 ± 0.21 

0.12 ± 0.03 

0.41 ± 0.08* 

1.59 ± 0.18** 

0.47 ± 0.09* 

0.30 ± 0.03 

0.51 ± 0.09 

1.24 ± 0.12 

1.42 ± 0.13 

2.30 ± 0.23 

5.54 ± 0.53 

0.062 ± 0.019 

0.14 ± 0.03 

0.26 ± 0.04 

0.10 ± 0.02 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

4.22 ± 0.71 

0.08 ± 0.02 

0.16 ± 0.04 

0.02 ± 0.01 

0.41 ± 0.06 

0.19 ± 0.03 

0.000 ± 0.000 

0.000 ± 0.000 

3.34 ± 0.33 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

1.27 ± 0.38 

0.14 ± 0.02 

0.49 ± 0.05 

1.59 ± 0.25** 

0.38 ± 0.05** 

0.45 ± 0.06 

0.60 ± 0.08 

1.61 ± 0.21 

1.47 ± 0.13 

3.06 ± 0.29 

6.97 ± 0.90 

0.021 ± 0.009 

0.14 ± 0.03 

0.22 ± 0.04 

0.12 ± 0.02 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

3.15 ± 0.40 

0.09 ± 0.03 

0.18 ± 0.04 

0.06 ± 0.02 

0.43 ± 0.07 

0.19 ± 0.06 

0.000 ± 0.000 

0.000 ± 0.000 

3.03 ± 0.40 

0.000 ± 0.000 

0.000 ± 0.000 

0.000 ± 0.000 

1.87 ± 0.43 

* Significantly different (P#0.05) from the control group by Dunn’s or Shirley’s test 

** P#0.01 a Mean ± standard error. Statistical tests were performed on unrounded data. b n=8
 

n=9
 d n=6 

c 
292 AZT and AZT/"-Interferon A/D, NTP TR 469 
293 

APPENDIX L
 

REPRODUCTIVE TISSUE EVALUATIONS
 

AND ESTROUS CYCLE CHARACTERIZATION
 

TABLE L1	 Summary of Reproductive Tissue Evaluations and Estrous Cycle Characterization 

for Mice in the 14-Week Gavage Study of AZT ............................. 294 
294 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE L1 

Summary of Reproductive Tissue Evaluations and Estrous Cycle Characterization for Mice 

in the 14-Week Gavage Study of AZTa 

Vehicle Control 100 mg/kg 800 mg/kg 2,000 mg/kg 

Male 

n 10 10 10 10 

Core Study 

Weights (g) 

Necropsy body wt 

L. cauda epididymis 

L. epididymis 

L. testis 

32.4 ± 0.6 

0.0195 ± 0.0010 

0.0470 ± 0.0014 

0.1152 ± 0.0026 

35.1 ± 1.1 

0.0215 ± 0.0015 

0.0526 ± 0.0019* 

0.1196 ± 0.0027 

33.8 ± 0.7 

0.0217 ± 0.0007 

0.0512 ± 0.0016b 

0.1119 ± 0.0046 

32.0 ± 0.6 

0.0194 ± 0.0009 

0.0443 ± 0.0013 

0.0996 ± 0.0020** 

Spermatid measurements 

Spermatid heads (10 /g testis) 7 

Spermatid heads (10 /testis) 7 

Spermatid count 

(mean/10 mL suspension) !4 

20.34 ± 1.32 

2.32 ± 0.12 

72.58 ± 3.90 

19.32 ± 0.76 

2.32 ± 0.11 

72.35 ± 3.56 

19.84 ± 1.03 

2.22 ± 0.15 

69.20 ± 4.63 

19.71 ± 0.81 

1.97 ± 0.10 

61.45 ± 3.07 

Epididymal spermatozoal measurements 

Motility (%) 

Concentration 

(10 /g cauda epididymal tissue) 6 

33.36 ± 6.69 

987 ± 87 

37.96 ± 5.58 

857 ± 61 

24.77 ± 4.64 

835 ± 60 

23.15 ± 3.37 

896 ± 93 

Recovery Study 

Weights (g) 

Necropsy body wt 

L. cauda epididymis 

L. epididymis 

L. testis 

37.1 ± 1.0 

0.0174 ± 0.0007b 

0.0471 ± 0.0009 

0.1175 ± 0.0021 

39.7 ± 0.6 

0.0181 ± 0.0008 

0.0493 ± 0.0012 

0.1180 ± 0.0028 

40.0 ± 1.2 

0.0178 ± 0.0005 

0.0493 ± 0.0010 

0.1177 ± 0.0026 

37.1 ± 0.9 

0.0182 ± 0.0007 

0.0461 ± 0.0011 

0.1122 ± 0.0014 

Spermatid measurements 

Spermatid heads (10 /g testis) 7 

Spermatid heads (10 /testis) 7 

Spermatid count 

(mean/10 mL suspension) !4 

21.23 ± 1.17 

2.50 ± 0.15 

78.20 ± 4.79 

23.29 ± 1.25 

2.73 ± 0.10 

85.23 ± 3.25 

23.14 ± 0.94 

2.71 ± 0.10 

84.75 ± 3.03 

23.09 ± 0.90 

2.59 ± 0.10 

80.83 ± 2.99 

Epididymal spermatozoal measurements 

Motility (%) 

Concentration 

(10 /g cauda epididymal tissue) 6 

92.49 ± 0.62 

1,582 ± 105b 

91.23 ± 0.82 

1,319 ± 59* 

91.89 ± 0.96 

1,466 ± 89 

91.80 ± 0.81 

1,023 ± 70** 
295 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE L1 

Summary of Reproductive Tissue Evaluations and Estrous Cycle Characterization for Mice 

in the 14-Week Gavage Study of AZT 

Vehicle Control 100 mg/kg 800 mg/kg 2,000 mg/kg 

Female 

n 10 10 10 9 

Initial smear (end of dosing) 

Estrous cycle length (days) 4.55 ± 0.16 4.28 ± 0.12c 4.55 ± 0.22 4.56 ± 0.18 

Estrous stages (% of cycle) 

Diestrus 25.0 33.3 24.2 28.7 

Proestrus 15.8 15.8 19.2 23.1 

Estrus 40.0 31.7 37.5 25.9 

Metestrus 18.3 17.5 19.2 19.4 

Uncertain diagnoses 0.8 1.7 0.0 2.8 

Final smear (end of recovery) 

Necropsy body wt 30.8 ± 1.5 32.2 ± 0.7 33.3 ± 1.1 29.8 ± 1.1 

Estrous cycle length (days) 4.25 ± 0.13 4.10 ± 0.07 4.25 ± 0.13 4.06 ± 0.06 

Estrous stages (% of cycle) 

Diestrus 27.5 36.7 27.5 31.5 

Proestrus 17.5 18.3 13.3 16.7 

Estrus 34.2 31.7 36.7 32.4 

Metestrus 20.8 23.3 22.5 19.4 

*	 Significantly different (P#0.05) from the vehicle control group by Dunnett’s test (core study, left epididymal weight) or Shirley’s test 

(recovery study, epididymal spermatozoal concentration) 

** Significantly different (P#0.01) from the vehicle control group by Williams’ test (core study, left testis weight) or Shirley’s test (recovery 

study, epididymal spermatozoal concentration) a Weights, spermatid and epididymal spermatozoal measurements, and estrous cycle lengths are presented as mean ± standard error. 

Differences from the vehicle control group for necropsy body weight, left cauda epididymal weight (core study), and organ weights 

(recovery study) are not significant by Dunnett’s test; differences from the vehicle control group for spermatid measurements, epididymal 

spermatozoal measurements (core study), epididymal spermatozoal motility (recovery study), and estrous cycle length are not significant by 

Dunn’s test. By multivariate analysis of variance, dosed females do not differ significantly from the vehicle control females in the relative 

length of time spent in the estrous stages. b n=9
 

Estrous cycle was longer than 12 days or was unclear in 1 of 10 animals.
 
296 AZT and AZT/"-Interferon A/D, NTP TR 469 
297 

APPENDIX M
 

NEUROBEHAVIORAL DATA
 

TABLE M1 Neurobehavioral Data for Mice in the 14-Week Gavage Study of AZT ............. 298
 
298 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE M1 

Neurobehavioral Data for Mice in the 14-Week Gavage Study of AZTa 

Vehicle Control 100 mg/kg 800 mg/kg 2,000 mg/kg 

Male 

Core Study 

n 10 10 10 10 

Body weight (g) 

Day !3 19.6 ± 1.0 19.7 ± 0.7 21.4 ± 0.5 21.6 ± 0.6 

Day 44 28.5 ± 0.4 28.8 ± 0.5 27.9 ± 0.4 28.0 ± 0.5 

Day 88 32.2 ± 0.6 34.5 ± 1.0 33.0 ± 0.7 31.6 ± 0.6 

Body temperature (E C) 

Day !3 36.5 ± 0.2 37.0 ± 0.2 37.3 ± 0.2** 38.0 ± 0.3** 

Day 44 37.2 ± 0.2 37.3 ± 0.2 36.9 ± 0.2 36.7 ± 0.1 

Day 88 37.1 ± 0.2 36.7 ± 0.2 36.9 ± 0.1 37.5 ± 0.3 

Landing footsplay (Trial 1) 

Day !3 47.4 ± 2.6 50.8 ± 2.4 43.7 ± 3.3 51.0 ± 3.2 

Day 44 42.1 ± 2.2 40.9 ± 2.9 37.5 ± 2.6 42.3 ± 1.2 

Day 88 39.7 ± 2.4 44.8 ± 2.6 44.8 ± 2.9 45.2 ± 1.9 

Landing footsplay (Trial 2) 

Day !3 44.5 ± 1.7 50.2 ± 1.6 48.2 ± 2.4 47.0 ± 1.6 

Day 44 37.6 ± 1.1 41.6 ± 1.8 38.8 ± 2.2 42.0 ± 2.0 

Day 88 41.4 ± 2.7 43.7 ± 2.3 41.2 ± 2.4 42.4 ± 2.1 

Landing footsplay (avg) 

Day !3 46.0 ± 1.9 50.5 ± 1.5 46.0 ± 2.6 49.0 ± 2.0 

Day 44 39.9 ± 1.0 41.3 ± 1.7 38.2 ± 2.0 42.2 ± 1.1 

Day 88 40.6 ± 2.5 44.3 ± 2.1 43.0 ± 2.2 43.8 ± 1.4 

Forelimb grip strength (Trial 1) 

Day !3 99.0 ± 5.4 115.0 ± 11.6 103.5 ± 8.2 113.5 ± 7.2 

Day 44 140.0 ± 6.2 141.0 ± 8.3 136.0 ± 5.0 131.0 ± 9.0 

Day 88 130.5 ± 5.4 126.0 ± 4.0 124.0 ± 3.6 130.0 ± 4.0 

Forelimb grip strength (Trial 2) 

Day !3 111.0 ± 6.3 100.0 ± 8.8 109.0 ± 6.0 111.5 ± 4.8 

Day 44 140.0 ± 6.8 143.0 ± 6.2 134.5 ± 8.2 136.5 ± 8.3 

Day 88 128.0 ± 6.2 132.5 ± 3.7 122.0 ± 3.6 128.5 ± 5.9 

Forelimb grip strength (avg) 

Day !3 105.0 ± 4.0 107.5 ± 9.4 106.3 ± 6.5 112.5 ± 4.2 

Day 44 140.0 ± 6.2 142.0 ± 6.5 135.3 ± 4.9 133.8 ± 7.7 

Day 88 129.3 ± 5.4 129.3 ± 3.8 123.0 ± 3.4 129.3 ± 4.8 

Hindlimb grip strength (Trial 1) 

Day !3 65.0 ± 6.2 46.0 ± 7.4 60.0 ± 8.9 60.5 ± 6.6 

Day 44 48.0 ± 5.0 60.5 ± 7.2 41.5 ± 3.9 60.5 ± 6.2 

Day 88 52.5 ± 3.4 56.5 ± 2.4 54.0 ± 2.4 55.5 ± 3.2 

Hindlimb grip strength (Trial 2) 

Day !3 57.5 ± 4.0 51.0 ± 6.3 63.0 ± 7.3 54.0 ± 7.1 

Day 44 62.5 ± 8.1 58.0 ± 5.8 56.5 ± 7.2 62.0 ± 6.2 

Day 88 52.0 ± 3.7 55.0 ± 2.8 54.5 ± 3.3 55.0 ± 3.6 

Hindlimb grip strength (avg) 

Day !3 62.3 ± 4.7 48.5 ± 6.3 61.5 ± 7.6 60.3 ± 4.3 

Day 44 55.3 ± 6.2 59.3 ± 5.4 49.0 ± 4.9 61.3 ± 5.8 

Day 88 52.3 ± 3.4 55.8 ± 2.4 53.8 ± 2.7 55.3 ± 3.3 

Total motor activity 

Day !3 837.8 ± 74.2 658.0 ± 97.2 745.9 ± 84.7 734.2 ± 109.6 

Day 44 1,534.6 ± 86.7 1,593.5 ± 128.4 1,287.9 ± 74.7 1,377.7 ± 114.9 

Day 88 1,593.0 ± 79.0 1,611.3 ± 319.2 1,183.2 ± 118.6 1,397.1 ± 175.1 

Ambulatory motor activity 

Day !3 550.9 ± 54.0 443.1 ± 71.6 427.8 ± 67.2 540.2 ± 62.1 

Day 44 1,090.3 ± 72.3 1,168.3 ± 99.0 884.8 ± 61.3 983.2 ± 84.2 

Day 88 1,141.7 ± 70.1 1,180.5 ± 245.6 838.7 ± 90.1 982.5 ± 132.9 
AZT and AZT/"-Interferon A/D, NTP TR 469 299 

TABLE M1 

Neurobehavioral Data for Mice in the 14-Week Gavage Study of AZT 

Vehicle Control 100 mg/kg 800 mg/kg 2,000 mg/kg 

Male (continued) 

Core Study (continued) 

n 10 10 10 10 

Total nonambulatory motor activity 

Day !3 286.9 ± 24.1 214.9 ± 30.6 318.1 ± 34.3 286.5 ± 19.7 

Day 44 444.3 ± 22.0 425.2 ± 33.5 403.1 ± 27.0 394.5 ± 36.8 

Day 88 451.3 ± 21.1 430.8 ± 74.9 344.5 ± 30.8 414.6 ± 48.4 

Thermal latency (seconds) 

Day !3 0.91 ± 0.09 0.96 ± 0.17 1.25 ± 0.18 0.92 ± 0.10 

Day 44 1.29 ± 0.26 0.85 ± 0.08 1.16 ± 0.21 1.11 ± 0.16 

Day 88 1.08 ± 0.12 1.16 ± 0.18 0.92 ± 0.07 0.92 ± 0.08 

Threshold crossing - acoustic (milliseconds) 

Day !3 23.5 ± 2.9b 

Day 44 80.4 ± 37.4f 

Day 88 38.0 ± 6.9h 

23.0 ± 1.0c 

46.7 ± 29.7g 

28.3 ± 5.4h 

93.0 ± 33.8d 

46.0 ± 8.0c 

51.7 ± 29.6e 

25.9 ± 8.2e 

19.0 ± 3.0c 

62.0 ± 19.8i 

Threshold crossing - air puff (latency) 

Day !3 

Day 44 

64.0 ± 10.2 

40.9 ± 6.8e 52.0 ± 11.1i 

41.4 ± 7.1e 54.2 ± 10.5 

65.3 ± 26.9h 

44.4 ± 9.2 

29.5 ± 4.6h 

Day 88 31.4 ± 3.8 28.0 ± 1.4 22.0 ± 4.1 22.2 ± 1.9 

Peak amplitude - acoustic (g) 

Day !3 

Day 44 

Day 88 

6.90 ± 0.65b 

8.80 ± 2.64f 

8.46 ± 0.94h 

10.70 ± 3.30c 

6.47 ± 0.18g 

10.83 ± 1.80h 

7.40 ± 1.02d 

5.95 ± 0.35c 

11.17 ± 2.71e 

7.47 ± 1.16e 

7.05 ± 0.95c 

7.79 ± 1.40i 

Peak amplitude - air puff (magnitude) 

Day !3 

Day 44 

14.6 ± 2.8 

13.9 ± 3.8e 11.1 ± 3.0i 

14.6 ± 5.1e 17.8 ± 4.3 

22.7 ± 11.5h 

17.1 ± 5.7 

14.5 ± 3.3h 

Day 88 26.2 ± 4.8 24.1 ± 7.0 18.0 ± 4.8 31.2 ± 7.2 

Time of peak - acoustic (milliseconds) 

Day !3 

Day 44 

Day 88 

31.0 ± 2.6b 

84.4 ± 36.5f 

42.0 ± 6.5h 

32.0 ± 4.0c 

49.3 ± 30.3g 

34.0 ± 4.9h 

98.0 ± 33.4d 

55.0 ± 13.0c 

56.9 ± 29.1e 

29.4 ± 7.6e 

22.0 ± 4.0c 

65.3 ± 19.6i 

Time of peak - air puff (latency) 

Day !3 

Day 44 

73.0 ± 10.1 

47.4 ± 7.0e 57.3 ± 11.2i 

49.1 ± 7.2e 64.2 ± 12.0 

83.3 ± 34.6h 

54.6 ± 9.5 

40.5 ± 2.7h 

Day 88 38.4 ± 3.8 35.0 ± 1.8 31.4 ± 4.2 31.0 ± 3.0 

Recovery Study 

n 10 10 10 10 

Body weight (g) 

Day !3 21.8 ± 0.3 22.6 ± 0.4 22.5 ± 0.4 22.1 ± 0.4 

Day 44 28.8 ± 0.5 29.2 ± 0.3 29.4 ± 0.6 27.9 ± 0.3 

Day 88 32.6 ± 0.8 34.1 ± 0.6 33.9 ± 0.9 32.0 ± 0.7 

Day 116 37.0 ± 0.9 38.9 ± 0.7 38.4 ± 1.2 37.0 ± 0.9 

Body temperature (E C) 

Day !3 37.1 ± 0.1 37.4 ± 0.1 38.1 ± 0.1** 37.4 ± 0.2 

Day 44 38.1 ± 0.2 37.4 ± 0.2 38.1 ± 0.2 37.9 ± 0.1 

Day 88 36.7 ± 0.2 36.3 ± 0.2 36.0 ± 0.2* 35.8 ± 0.2** 

Day 116 38.1 ± 0.2 37.5 ± 0.2 37.7 ± 0.2 37.4 ± 0.5 

Landing footsplay (Trial 1) 

Day !3 49.3 ± 2.2 48.7 ± 1.4 47.5 ± 2.5 44.5 ± 1.8 

Day 44 45.5 ± 3.1 40.7 ± 1.8 44.7 ± 3.0 39.9 ± 2.9 

Day 88 41.2 ± 2.4 45.8 ± 3.4 40.9 ± 1.8 42.5 ± 2.8 

Day 117 41.6 ± 2.4 44.8 ± 1.9 44.8 ± 2.4 41.7 ± 2.3 
300 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE M1 

Neurobehavioral Data for Mice in the 14-Week Gavage Study of AZT 

Vehicle Control 100 mg/kg 800 mg/kg 2,000 mg/kg 

Male (continued) 

Recovery Study (continued) 

n 10 10 10 10 

Landing footsplay (Trial 2) 

Day !3 46.2 ± 1.9 47.7 ± 2.3 47.8 ± 2.6 45.0 ± 2.3 

Day 44 46.0 ± 2.5 43.1 ± 2.4 42.2 ± 2.2 39.6 ± 2.8 

Day 88 38.6 ± 1.9 42.9 ± 2.1 40.4 ± 3.1 43.6 ± 2.3 

Day 117 38.8 ± 1.7 46.0 ± 2.8* 43.4 ± 2.3 43.9 ± 1.9 

Landing footsplay (avg) 

Day !3 47.8 ± 1.6 48.2 ± 1.6 47.7 ± 1.4 44.8 ± 1.6 

Day 44 45.8 ± 1.9 41.9 ± 1.1 43.5 ± 2.1 39.8 ± 2.4 

Day 88 39.9 ± 2.0 44.4 ± 2.0 40.7 ± 2.2 43.1 ± 2.1 

Day 117 40.2 ± 2.0 45.4 ± 2.1 44.1 ± 2.1 42.8 ± 1.7 

Forelimb grip strength (Trial 1) 

Day !3 98.5 ± 5.5 101.5 ± 6.9 100.0 ± 7.8 105.0 ± 6.0 

Day 44 150.0 ± 7.0 140.5 ± 5.6 140.0 ± 10.4 144.5 ± 9.4 

Day 88 139.0 ± 8.3 124.5 ± 4.7 136.5 ± 7.8 126.5 ± 6.3 

Day 117 145.0 ± 8.5 147.5 ± 8.9 147.5 ± 9.1 153.5 ± 4.3 

Forelimb grip strength (Trial 2) 

Day !3 89.0 ± 6.3 107.5 ± 6.9 102.5 ± 6.9 109.5 ± 9.0 

Day 44 156.0 ± 7.8 152.0 ± 4.8 151.0 ± 10.3 135.5 ± 4.8 

Day 88 132.5 ± 8.1 133.0 ± 7.9 132.5 ± 7.6 133.0 ± 7.3 

Day 117 162.5 ± 4.8 145.0 ± 7.4 155.5 ± 7.2 152.0 ± 3.3 

Forelimb grip strength (avg) 

Day !3 93.8 ± 2.8 104.5 ± 5.8 101.3 ± 6.5 107.3 ± 5.5 

Day 44 153.0 ± 5.1 146.3 ± 4.3 145.5 ± 8.1 140.0 ± 5.3 

Day 88 135.8 ± 7.5 128.8 ± 6.0 134.5 ± 7.6 129.8 ± 6.6 

Day 117 153.8 ± 5.9 146.3 ± 7.4 151.5 ± 7.8 152.8 ± 2.9 

Hindlimb grip strength (Trial 1) 

Day !3 46.5 ± 10.2 48.5 ± 9.0 52.0 ± 4.8 42.5 ± 4.5 

Day 44 50.5 ± 8.1 56.0 ± 3.4 57.0 ± 5.3 54.5 ± 6.5 

Day 88 57.0 ± 5.6 60.5 ± 5.9 56.5 ± 4.6 58.5 ± 4.5 

Day 117 89.5 ± 6.2 81.0 ± 5.7 86.5 ± 4.9 81.5 ± 9.6 

Hindlimb grip strength (Trial 2) 

Day !3 36.5 ± 2.2 45.5 ± 7.9 53.0 ± 7.2 40.0 ± 5.8 

Day 44 55.5 ± 8.3 63.0 ± 6.4 63.0 ± 8.2 41.0 ± 5.4 

Day 88 58.5 ± 3.7 62.5 ± 5.6 63.0 ± 4.2 61.5 ± 7.5 

Day 117 89.0 ± 7.5 77.5 ± 4.8 77.5 ± 4.5 81.0 ± 8.6 

Hindlimb grip strength (avg) 

Day !3 41.5 ± 5.7 47.0 ± 8.0 52.5 ± 4.0 41.3 ± 3.6 

Day 44 53.0 ± 5.7 59.5 ± 4.1 60.0 ± 6.3 47.8 ± 5.5 

Day 88 57.8 ± 4.5 61.5 ± 5.7 59.8 ± 3.9 60.0 ± 5.9 

Day 117 89.3 ± 5.0 79.3 ± 3.8 82.0 ± 4.0 81.3 ± 7.6 

Total motor activity 

Day !3 643.3 ± 87.4 857.4 ± 81.2 767.2 ± 112.6 749.8 ± 94.3 

Day 44 1,227.7 ± 80.5 1,257.0 ± 101.1 1,207.0 ± 146.8 1,189.7 ± 69.5 

Day 88 1,549.4 ± 369.5 1,390.8 ± 218.3 1,360.8 ± 232.0 1,129.7 ± 82.8 

Day 117 1,184.4 ± 74.7 1,232.4 ± 73.8 1,231.2 ± 84.5 1,210.5 ± 71.9 

Ambulatory motor activity 

Day !3 376.1 ± 55.2 538.2 ± 72.2 513.9 ± 88.1 468.9 ± 60.8 

Day 44 786.8 ± 65.6 882.9 ± 81.1 848.8 ± 117.1 799.1 ± 47.6 

Day 88 1,090.1 ± 318.1 966.2 ± 182.0 966.1 ± 193.7 718.9 ± 56.4 

Day 117 802.4 ± 54.7 848.3 ± 71.7 830.3 ± 70.0 829.3 ± 62.0 
AZT and AZT/"-Interferon A/D, NTP TR 469 301 

TABLE M1 

Neurobehavioral Data for Mice in the 14-Week Gavage Study of AZT 

Vehicle Control 100 mg/kg 800 mg/kg 2,000 mg/kg 

Male (continued) 

Recovery Study (continued) 

n 10 10 10 10 

Total nonambulatory motor activity 

Day !3 267.2 ± 37.9 319.2 ± 36.9 253.3 ± 29.1 280.9 ± 39.5 

Day 44 440.9 ± 32.5 374.1 ± 29.8 358.2 ± 38.4 390.6 ± 28.0 

Day 88 459.3 ± 56.8 424.6 ± 39.2 394.7 ± 42.4 410.8 ± 35.1 

Day 117 382.0 ± 30.7 384.1 ± 12.9 400.9 ± 26.5 381.2 ± 25.2 

Thermal latency (seconds) 

Day !3 0.99 ± 0.10 0.81 ± 0.05 1.09 ± 0.17 1.11 ± 0.10 

Day 44 1.36 ± 0.17 0.96 ± 0.10 1.39 ± 0.19 1.11 ± 0.11 

Day 88 0.94 ± 0.13 1.24 ± 0.16 1.33 ± 0.14 1.03 ± 0.11 

Day 117 1.62 ± 0.15 1.51 ± 0.11 1.31 ± 0.10 1.51 ± 0.11 

Threshold crossing - acoustic (milliseconds) 

Day !3 38.0 ± 7.3d 

Day 44 48.9 ± 21.7i 

Day 88 30.4 ± 6.5 

Day 117 62.7 ± 27.2i 

86.7 ± 47.7d 

49.7 ± 20.7e 

27.4 ± 3.2 

52.0 ± 15.7i 

37.1 ± 5.2e 

32.4 ± 8.3f 

47.6 ± 12.7 

34.4 ± 9.8i 

98.9 ± 33.9e 

56.9 ± 26.9e 

27.6 ± 4.6i 

56.5 ± 15.7h 

Threshold crossing - air puff (latency) 

Day !3 37.6 ± 5.5 35.6 ± 8.3 38.2 ± 9.1 35.4 ± 6.2 

Day 44 

Day 88 

33.8 ± 5.5 

23.8 ± 0.8 

25.4 ± 3.8 

23.0 ± 3.8 

29.8 ± 3.6 

28.2 ± 2.2 

33.2 ± 4.2 

21.1 ± 3.0i 

Day 117 27.6 ± 1.3 27.2 ± 0.8 28.2 ± 2.4 27.4 ± 1.1 

Peak amplitude - acoustic (g) 

Day !3 

Day 44 

Day 88 

Day 117 

7.45 ± 1.13d 

8.57 ± 0.75i 

11.85 ± 3.55 

6.32 ± 0.38i 

5.60 ± 1.01e 

10.76 ± 2.43e 

10.38 ± 1.55 

7.61 ± 0.51i 

7.61 ± 0.57e 

10.62 ± 3.72f 

6.60 ± 0.65 

9.90 ± 1.37*i 

7.33 ± 0.87e 

14.30 ± 7.96e 

9.01 ± 0.78i 

6.99 ± 0.64h 

Peak amplitude - air puff (magnitude) 

Day !3 43.7 ± 19.3 24.3 ± 10.2 18.5 ± 5.8 33.6 ± 10.3 

Day 44 

Day 88 

19.7 ± 3.0 

18.7 ± 4.3 

15.4 ± 4.2 

23.4 ± 5.4 

26.0 ± 11.6 

18.0 ± 4.2 

15.4 ± 4.5 

18.1 ± 4.8i 

Day 117 15.5 ± 2.7 17.2 ± 2.5 16.4 ± 2.4 12.6 ± 2.5 

Time of peak - acoustic (milliseconds) 

Day !3 

Day 44 

Day 88 

Day 117 

41.3 ± 6.7d 

55.6 ± 21.5i 

35.2 ± 6.8 

64.7 ± 27.0i 

91.0 ± 47.3d 

58.6 ± 20.1e 

34.6 ± 4.0 

58.2 ± 16.0i 

42.3 ± 4.8e 

38.0 ± 7.0f 

36.4 ± 5.6 

38.2 ± 9.9i 

104.0 ± 32.7e 

60.0 ± 26.9e 

32.4 ± 4.6i 

59.5 ± 16.8h 

Time of peak - air puff (latency) 

Day !3 44.5 ± 8.0 47.6 ± 9.9 49.4 ± 9.4 53.6 ± 11.7 

Day 44 

Day 88 

43.0 ± 6.2 

32.2 ± 2.6 

31.6 ± 4.8 

33.2 ± 5.8 

37.6 ± 5.1 

35.0 ± 2.2 

43.2 ± 7.5 

28.9 ± 3.9i 

Day 117 33.6 ± 2.3 35.8 ± 3.4 33.4 ± 2.3 30.2 ± 3.8 
302 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE M1 

Neurobehavioral Data for Mice in the 14-Week Gavage Study of AZT 

Vehicle Control 100 mg/kg 800 mg/kg 2,000 mg/kg 

Female 

Core Study 

n 

Day !3 10 10 10 10 

Day 44 10 9 10 10 

Day 88 10 9 10 9 

Body weight (g) 

Day !3 15.5 ± 0.6 15.3 ± 0.5 17.2 ± 0.5 17.0 ± 0.5 

Day 44 23.9 ± 0.7 23.9 ± 0.2 23.3 ± 0.4 23.3 ± 0.5 

Day 88 29.1 ± 1.3 28.1 ± 0.4 27.5 ± 0.7 27.0 ± 1.0 

Body temperature (E C) 

Day !3 37.0 ± 0.3 36.8 ± 0.2 37.3 ± 0.2 37.5 ± 0.2 

Day 44 37.8 ± 0.1 37.8 ± 0.1 37.9 ± 0.2 37.7 ± 0.1 

Day 88 37.2 ± 0.1 37.0 ± 0.1 36.6 ± 0.1* 36.8 ± 0.1 

Landing footsplay (Trial 1) 

Day !3 43.1 ± 2.8 40.3 ± 1.9 43.9 ± 2.4 41.6 ± 2.7 

Day 44 44.5 ± 2.3 45.7 ± 2.9 41.2 ± 2.4 48.2 ± 2.2 

Day 88 45.1 ± 2.6 41.9 ± 2.3 45.5 ± 2.5 41.9 ± 1.3 

Landing footsplay (Trial 2) 

Day !3 44.0 ± 1.7 43.0 ± 2.8 41.8 ± 1.5 48.0 ± 2.4 

Day 44 39.2 ± 1.3 43.0 ± 2.2 40.9 ± 1.3 41.8 ± 2.3 

Day 88 44.1 ± 2.4 40.6 ± 1.6 42.4 ± 2.5 40.2 ± 1.6 

Landing footsplay (avg) 

Day !3 43.6 ± 1.4 41.7 ± 2.0 42.9 ± 1.4 44.8 ± 1.4 

Day 44 41.9 ± 1.5 44.3 ± 2.0 41.1 ± 1.5 45.0 ± 1.5 

Day 88 44.6 ± 2.0 41.2 ± 1.7 44.0 ± 1.9 41.1 ± 1.0 

Forelimb grip strength (Trial 1) 

Day !3 106.0 ± 8.8 107.5 ± 6.7 96.5 ± 4.1 86.5 ± 8.2 

Day 44 106.5 ± 2.4 104.4 ± 2.4 103.5 ± 3.9 108.0 ± 2.5 

Day 88 105.0 ± 2.7 110.0 ± 7.6 107.5 ± 5.9 114.4 ± 4.1 

Forelimb grip strength (Trial 2) 

Day !3 107.0 ± 7.2 111.5 ± 9.9 97.5 ± 5.7 108.0 ± 6.1 

Day 44 106.0 ± 1.5 99.4 ± 3.4 102.5 ± 4.0 108.0 ± 2.0 

Day 88 105.5 ± 4.8 105.0 ± 5.7 108.0 ± 7.2 116.7 ± 6.2 

Forelimb grip strength (avg) 

Day !3 106.5 ± 6.4 109.5 ± 6.8 97.0 ± 4.2 97.3 ± 5.5 

Day 44 106.3 ± 1.5 101.9 ± 1.9 103.0 ± 3.7 108.0 ± 1.7 

Day 88 105.3 ± 3.3 107.5 ± 6.4 107.8 ± 5.9 115.6 ± 4.1 

Hindlimb grip strength (Trial 1) 

Day !3 38.0 ± 6.1 39.5 ± 3.8 47.0 ± 10.1 43.5 ± 5.2 

Day 44 50.0 ± 2.5 43.9 ± 2.2 51.0 ± 3.1 46.0 ± 2.3 

Day 88 53.5 ± 3.4 50.0 ± 3.2 52.5 ± 4.8 50.6 ± 4.4 

Hindlimb grip strength (Trial 2) 

Day !3 33.5 ± 6.0 41.0 ± 6.0 43.0 ± 5.4 34.0 ± 4.6 

Day 44 49.5 ± 1.7 44.4 ± 2.3 52.0 ± 2.5 47.5 ± 2.6 

Day 88 51.5 ± 3.0 52.8 ± 5.1 53.0 ± 3.4 50.6 ± 5.3 

Hindlimb grip strength (avg) 

Day !3 35.8 ± 3.9 40.3 ± 4.4 45.0 ± 7.1 38.8 ± 4.6 

Day 44 49.8 ± 1.9 44.2 ± 2.2 51.5 ± 2.7 46.8 ± 2.4 

Day 88 52.5 ± 3.1 51.4 ± 3.6 52.8 ± 4.0 50.6 ± 4.5 

Total motor activity 

Day !3 718.0 ± 95.6 566.4 ± 56.3 655.8 ± 94.7 786.7 ± 61.8 

Day 44 1,020.8 ± 71.4 972.3 ± 96.8 1,001.7 ± 101.3 817.1 ± 102.8 

Day 88 934.3 ± 51.4 1,016.8 ± 48.2 999.4 ± 46.7 851.6 ± 96.1 

Ambulatory motor activity 

Day !3 474.9 ± 70.5 351.9 ± 32.6 414.4 ± 70.9 464.7 ± 50.9 

Day 44 689.2 ± 56.0 675.0 ± 68.6 682.6 ± 81.8 520.5 ± 65.9 

Day 88 619.9 ± 47.4 660.9 ± 40.3 659.3 ± 42.5 571.3 ± 68.4 
AZT and AZT/"-Interferon A/D, NTP TR 469 303 

TABLE M1 

Neurobehavioral Data for Mice in the 14-Week Gavage Study of AZT 

Vehicle Control 100 mg/kg 800 mg/kg 2,000 mg/kg 

Female (continued) 

Core Study (continued) 

n 

Day !3 10 10 10 10 

Day 44 10 9 10 10 

Day 88 10 9 10 9 

Total nonambulatory motor activity 

Day !3 243.1 ± 28.1 214.5 ± 28.1 241.4 ± 30.1 322.0 ± 29.1 

Day 44 331.6 ± 22.5 297.3 ± 35.2 329.1 ± 29.7 296.6 ± 43.3 

Day 88 314.4 ± 15.2 355.9 ± 14.3 340.1 ± 16.8 280.2 ± 30.2 

Thermal latency (seconds) 

Day !3 1.22 ± 0.20 1.25 ± 0.20 1.15 ± 0.13 1.11 ± 0.16 

Day 44 0.70 ± 0.04 0.78 ± 0.09 0.76 ± 0.03 0.84 ± 0.09 

Day 88 0.80 ± 0.10 0.72 ± 0.04 0.83 ± 0.08 0.76 ± 0.06 

Threshold crossing - acoustic (milliseconds) 

Day !3 —j 

Day 44 32.0k 

Day 88 26.0 ± 6.6h 

148.0k 

44.0 ± 14.7g 

68.5 ± 27.3h 

— 

310.0k 

96.5 ± 37.3h 

— 

34.0 ± 12.0c 

40.9 ± 8.9e 

Threshold crossing - air puff (latency) 

Day !3 

Day 44 

49.6 ± 7.4 

80.9 ± 40.5e 50.6 ± 5.0 

54.7 ± 14.5d 

58.4 ± 10.7 

56.4 ± 13.9i 

48.0 ± 5.6 

72.0 ± 31.5h 

Day 88 31.2 ± 1.8 28.0 ± 1.2 23.6 ± 1.2** 32.9 ± 4.9 

Peak amplitude - acoustic (g) 

Day !3 

Day 44 

Day 88 

— 

8.10k 

13.56 ± 5.64h 

5.90k 

6.30 ± 0.92g 

6.73 ± 0.89h 

— 

6.30k 

6.73 ± 0.81h 

— 

7.40 ± 1.70c 

8.09 ± 1.76e 

Peak amplitude - air puff (magnitude) 

Day !3 

Day 44 

14.0 ± 3.1 

14.6 ± 2.9e 17.9 ± 3.6 

12.4 ± 2.8d 

10.0 ± 1.4 

8.1 ± 1.3i 

15.5 ± 2.5 

14.3 ± 3.7h 

Day 88 20.8 ± 6.8 18.8 ± 3.6 25.5 ± 6.9 27.4 ± 6.5 

Time of peak - acoustic (milliseconds) 

Day !3 

Day 44 

Day 88 

— 

36.0k 

28.5 ± 6.1h 

154.0k 

46.0 ± 13.6g 

70.0 ± 27.0h 

— 

314.0k 

98.8 ± 36.9h 

— 

38.0 ± 12.0c 

43.1 ± 8.6e 

Time of peak - air puff (latency) 

Day !3 

Day 44 

59.0 ± 5.4 

99.1 ± 49.6e 67.4 ± 7.7 

59.3 ± 13.8d 

71.6 ± 10.2 

58.9 ± 13.8i 

62.4 ± 5.5 

79.5 ± 30.4h 

Day 88 40.2 ± 3.3 34.4 ± 2.1 31.0 ± 2.6 44.7 ± 6.3 

Recovery Study 

n 

Day !3 10 10 10 10 

Day 44 10 10 10 9 

Day 88 10 10 10 9 

Day 116 10 10 10 9 

Body weight (g) 

Day !3 17.3 ± 0.6 18.6 ± 0.2 17.3 ± 0.7 18.2 ± 0.4 

Day 44 23.6 ± 0.7 23.5 ± 0.6 24.1 ± 0.4 23.5 ± 0.3 

Day 88 27.5 ± 0.9 28.1 ± 0.5 28.3 ± 0.7 26.6 ± 0.6 

Day 116 31.3 ± 1.4 32.1 ± 0.6 33.3 ± 1.0 30.4 ± 1.0 

Body temperature (E C) 

Day !3 37.8 ± 0.1 37.7 ± 0.1 37.8 ± 0.1 37.5 ± 0.1 

Day 44 38.0 ± 0.1 38.1 ± 0.1 37.9 ± 0.1 37.9 ± 0.1 

Day 88 37.5 ± 0.1 37.1 ± 0.2 37.0 ± 0.2* 37.1 ± 0.1 

Day 116 37.2 ± 0.1 37.5 ± 0.2 37.1 ± 0.2 37.6 ± 0.1 
304 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE M1 

Neurobehavioral Data for Mice in the 14-Week Gavage Study of AZT 

Vehicle Control 100 mg/kg 800 mg/kg 2,000 mg/kg 

Female (continued) 

Recovery Study (continued) 

n 

Day !3 10 10 10 10 

Day 44 10 10 10 9 

Day 88 10 10 10 9 

Day 116 10 10 10 9 

Landing footsplay (Trial 1) 

Day !3 46.4 ± 1.7 46.6 ± 1.9 44.2 ± 2.3 44.3 ± 2.6 

Day 44 41.9 ± 3.2 42.8 ± 2.7 40.6 ± 3.3 45.9 ± 3.2 

Day 88 40.5 ± 3.6 45.2 ± 1.7 44.8 ± 2.0 37.9 ± 1.2 

Day 116 43.9 ± 3.2 45.7 ± 4.3 50.9 ± 1.4 49.4 ± 3.7 

Landing footsplay (Trial 2) 

Day !3 44.3 ± 2.9 42.7 ± 2.1 46.2 ± 2.0 45.3 ± 2.7 

Day 44 44.8 ± 3.0 43.4 ± 3.2 36.2 ± 1.6 45.2 ± 3.4 

Day 88 44.6 ± 2.2 39.8 ± 2.1 42.3 ± 3.3 40.0 ± 1.8 

Day 116 45.6 ± 2.3 47.3 ± 1.8 48.6 ± 1.8 48.1 ± 4.0 

Landing footsplay (avg) 

Day !3 45.4 ± 2.1 44.7 ± 1.3 45.2 ± 1.9 44.8 ± 1.7 

Day 44 43.4 ± 2.5 43.1 ± 2.5 38.4 ± 2.0 45.6 ± 2.9 

Day 88 42.6 ± 2.8 42.5 ± 1.6 43.6 ± 2.4 38.9 ± 1.3 

Day 116 44.8 ± 2.6 46.2 ± 2.9 50.3 ± 1.3 48.8 ± 3.4 

Forelimb grip strength (Trial 1) 

Day !3 101.5 ± 6.1 104.0 ± 8.6 95.5 ± 12.1 121.5 ± 7.1 

Day 44 123.0 ± 8.1 124.0 ± 7.6 113.0 ± 7.1 117.8 ± 8.6 

Day 88 119.5 ± 6.7 129.0 ± 8.5 128.5 ± 9.0 125.0 ± 8.1 

Day 116 99.0 ± 6.7 103.0 ± 5.2 99.5 ± 8.0 103.3 ± 9.1 

Forelimb grip strength (Trial 2) 

Day !3 108.0 ± 8.4 97.5 ± 3.8 93.0 ± 5.6 115.5 ± 8.9 

Day 44 122.5 ± 7.4 115.5 ± 7.0 113.0 ± 7.2 116.1 ± 6.5 

Day 88 130.0 ± 9.9 115.5 ± 5.7 120.5 ± 7.9 123.9 ± 8.2 

Day 116 101.0 ± 6.7 101.5 ± 5.0 96.0 ± 7.2 95.0 ± 7.5 

Forelimb grip strength (avg) 

Day !3 104.8 ± 6.4 100.8 ± 4.5 94.3 ± 7.2 118.5 ± 4.4 

Day 44 122.8 ± 6.6 119.8 ± 6.1 113.0 ± 6.6 116.9 ± 7.4 

Day 88 124.8 ± 7.2 122.3 ± 6.2 124.5 ± 6.5 124.4 ± 7.2 

Day 116 100.0 ± 6.4 102.3 ± 4.6 97.8 ± 7.5 99.2 ± 7.5 

Hindlimb grip strength (Trial 1) 

Day !3 60.5 ± 9.0 48.0 ± 11.5 69.0 ± 10.7 58.0 ± 7.6 

Day 44 51.5 ± 3.1 56.5 ± 6.4 54.0 ± 6.0 43.3 ± 4.9 

Day 88 57.0 ± 5.0 52.5 ± 2.8 66.3 ± 8.1 55.6 ± 5.7 

Day 116 54.0 ± 3.3 55.5 ± 3.8 51.0 ± 3.7 45.6 ± 3.5 

Hindlimb grip strength (Trial 2) 

Day !3 58.5 ± 11.2 67.0 ± 10.7 66.5 ± 11.2 70.5 ± 10.8 

Day 44 58.0 ± 3.9 49.5 ± 4.0 58.5 ± 4.0 44.4 ± 3.2 

Day 88 61.0 ± 3.5 55.5 ± 5.5 62.5 ± 4.6 50.6 ± 7.8 

Day 116 51.5 ± 4.1 54.5 ± 4.0 49.5 ± 2.0 53.3 ± 4.2 

Hindlimb grip strength (avg) 

Day !3 59.5 ± 9.6 47.5 ± 7.1 67.8 ± 9.4 64.3 ± 8.9 

Day 44 54.8 ± 2.3 53.0 ± 4.8 56.3 ± 4.0 43.9 ± 3.3* 

Day 88 59.0 ± 4.1 54.0 ± 3.4 64.4 ± 5.6 53.1 ± 6.1 

Day 116 52.8 ± 3.4 55.0 ± 3.8 50.3 ± 2.5 49.4 ± 3.4 

Total motor activity 

Day !3 557.5 ± 81.5 618.7 ± 57.7 641.4 ± 86.1 612.0 ± 77.4 

Day 44 956.0 ± 54.6 847.8 ± 67.9 898.4 ± 64.3 853.1 ± 75.4 

Day 88 886.1 ± 54.2 906.4 ± 57.0 940.8 ± 68.2 867.1 ± 75.7 

Day 116 1,199.1 ± 154.6 1,081.6 ± 168.8 1,142.2 ± 191.3 1,093.3 ± 91.7 
AZT and AZT/"-Interferon A/D, NTP TR 469 305 

TABLE M1 

Neurobehavioral Data for Mice in the 14-Week Gavage Study of AZT 

Vehicle Control 100 mg/kg 800 mg/kg 2,000 mg/kg 

Female (continued) 

Recovery Study (continued) 

n 

Day !3 10 10 10 10 

Day 44 10 10 10 9 

Day 88 10 10 10 9 

Day 116 10 10 10 9 

Ambulatory motor activity 

Day !3 349.0 ± 62.6 395.1 ± 38.4 414.1 ± 57.1 373.2 ± 51.6 

Day 44 586.6 ± 28.3 549.7 ± 49.0 600.1 ± 45.5 550.3 ± 49.9 

Day 88 552.2 ± 38.8 590.0 ± 47.2 615.9 ± 51.1 570.7 ± 57.4 

Day 116 779.6 ± 110.9 662.4 ± 118.1 688.9 ± 126.2 671.2 ± 74.4 

Total nonambulatory motor activity 

Day !3 208.5 ± 30.4 223.6 ± 30.2 227.3 ± 33.8 238.8 ± 32.8 

Day 44 369.4 ± 34.6 298.1 ± 21.9 298.3 ± 26.7 302.8 ± 30.5 

Day 88 333.9 ± 23.7 316.4 ± 20.5 324.9 ± 27.3 296.4 ± 26.4 

Day 116 419.5 ± 50.5 419.2 ± 56.0 453.2 ± 74.8 422.1 ± 36.3 

Thermal latency (seconds) 

Day !3 1.31 ± 0.14 1.29 ± 0.14 1.21 ± 0.15 1.16 ± 0.29 

Day 44 0.92 ± 0.14 0.71 ± 0.04 0.85 ± 0.04 0.89 ± 0.15 

Day 88 0.80 ± 0.07 0.74 ± 0.06 0.74 ± 0.04 0.76 ± 0.05 

Day 116 1.10 ± 0.15 1.13 ± 0.10 1.21 ± 0.16 1.70 ± 0.84 

Threshold crossing - acoustic (milliseconds) 

Day !3 

Day 44 

Day 88 

Day 116 

40.0 ± 18.0c 

30.7 ± 7.7g 

35.4 ± 9.2e 

38.9 ± 6.7e 

36.0 ± 14.0c 

160.5 ± 28.8b 

35.8 ± 5.3i 

92.5 ± 30.8h 

35.0 ± 13.0c 

72.5 ± 51.2b 

104.0 ± 30.1d 

33.8 ± 6.1h 

— 

121.3 ± 27.3g 

63.4 ± 28.1e 

63.7 ± 28.6e 

Threshold crossing - air puff (latency) 

Day !3 46.1 ± 6.5 42.4 ± 4.8 47.8 ± 5.2 44.2 ± 3.7i 

Day 44 43.4 ± 6.0 44.0 ± 4.7 38.4 ± 7.7 42.2 ± 3.8 

Day 88 

Day 116 

29.2 ± 7.2 

27.6 ± 1.0 

30.8 ± 4.6 

28.4 ± 3.7 

32.6 ± 5.7 

31.6 ± 2.1i 

32.9 ± 5.2 

27.3 ± 1.2 

Peak amplitude - acoustic (g) 

Day !3 

Day 44 

Day 88 

Day 116 

21.37 ± 14.82g 

6.90 ± 0.55g 

7.49 ± 1.09e 

6.71 ± 0.43e 

5.65 ± 0.25c 

6.58 ± 0.46b 

7.31 ± 0.51i 

8.25 ± 1.44h 

6.25 ± 0.15c 

6.48 ± 0.80b 

5.52 ± 0.20d 

8.89 ± 2.32h 

— 

6.20 ± 0.53g 

7.69 ± 1.31e 

5.94 ± 0.29e 

Peak amplitude - air puff (magnitude) 

Day !3 18.8 ± 5.6 26.8 ± 10.3 13.2 ± 2.8 13.2 ± 3.6i 

Day 44 13.2 ± 2.5 9.6 ± 2.4 13.6 ± 3.7 14.2 ± 3.5 

Day 88 

Day 116 

14.3 ± 3.2 

46.8 ± 16.9 

11.1 ± 1.7 

19.3 ± 3.8 

19.4 ± 3.9 

20.5 ± 8.2i 

13.2 ± 2.7 

22.4 ± 6.1 

Time of peak - acoustic (milliseconds) 

Day !3 

Day 44 

Day 88 

Day 116 

29.3 ± 15.7g 

33.3 ± 8.4g 

37.4 ± 8.7e 

42.0 ± 6.9e 

38.0 ± 14.0c 

165.0 ± 27.7b 

38.9 ± 5.4i 

99.0 ± 31.4h 

39.0 ± 17.0c 

74.0 ± 50.7b 

106.3 ± 30.6d 

37.5 ± 6.0h 

— 

126.0 ± 26.4g 

66.6 ± 28.3e 

66.3 ± 28.2e 

Time of peak - air puff (latency) 

Day !3 66.4 ± 8.4 50.6 ± 3.2 57.6 ± 6.5 50.9 ± 5.3i 

Day 44 52.2 ± 4.7 47.0 ± 4.5 45.0 ± 7.1 52.4 ± 4.4 

Day 88 

Day 116 

34.4 ± 7.6 

37.6 ± 2.8 

34.2 ± 4.9 

35.2 ± 4.7 

42.2 ± 6.6 

42.4 ± 6.2i 

37.6 ± 5.5 

33.1 ± 1.9 

* Significantly different (P#0.05) from the control group by Dunn’s or Shirley’s test 

** P#0.01 a Mean ± standard error. Statistical tests were performed on unrounded data. Body weights of dosed animals were not significantly different 

from those of the control group by Williams’ or Dunnett’s test. b c d e f g h i j k n=4 n=2 n=6 n=7 n=5 n=3 n=8 n=9 n=0 n=1 
306 AZT and AZT/"-Interferon A/D, NTP TR 469 
307 

APPENDIX N
 

DETERMINATIONS OF
 

AZT CONCENTRATIONS IN PLASMA
 

TABLE N1 Plasma Concentrations of AZT in Mice in the 2-Year Gavage Study of AZT ......... 308
 
308 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE N1 

Plasma Concentrations of AZT in Mice in the 2-Year Gavage Study of AZTa 

Vehicle Control 30 mg/kg 60 mg/kg 120 mg/kg 

Male 

Clinical Pathology Groups 

n 3 3 3 3 

Time After Dosing (minutes) 

15 

30 

60 

90 

120 

—b 

— 

— 

— 

— 

5.50 ± 0.69 

3.38 ± 0.91 

0.862 ± 0.41 

0.389 ± 0.30 

0.198 ± 0.053 

12.4 ± 2.5 

6.56 ± 1.5 

1.69 ± 0.46 

0.599 ± 0.43 

0.505 ± 0.14 

20.9 ± 9.2 

11.3 ± 0.67 

6.43 ± 2.4 

2.10 ± 0.25 

0.633 ± 0.46 

Core Groups 

n —c 3 3 3 

Time After Dosing (minutes) 

0d 

5 

15 

30 

60 

90 

120 

— 

10.4 ± 3.8 

12.7 ± 1.4 

7.62 ± 3.6 

4.64 ± 1.2 

1.55 ± 0.58 

1.81 ± 2.4 

— 

20.1 ± 6.6 

24.2 ± 5.1 

16.9 ± 4.6 

8.58 ± 4.2 

2.36 ± 1.1 

1.92 ± 1.8 

— 

47.8 ± 4.6 

60.4 ± 30 

67.0 ± 14 

24.8 ± 16 

23.9 ± 23 

10.3 ± 0.59 

Female 

Clinical Pathology Groups 

n 3 3 3 3 

Time After Dosing (minutes) 

15 

30 

60 

90 

120 

— 

— 

— 

— 

— 

11.8 ± 1.5 

7.60 ± 1.1 

2.42 ± 0.78 

0.483 ± 0.22 

0.224 ± 0.11 

24.8 ± 4.5 

17.7 ± 4.9 

6.08 ± 4.7 

1.64 ± 0.70 

0.501e 

53.1 ± 5.1 

58.0 ± 23 

11.3 ± 1.3 

3.31 ± 1.9 

1.29e 

Core Groups 

n —c 3 3 3 

Time After Dosing (minutes) 

0d 

5 

15 

30 

60 

90 

120 

— 

14.3 ± 3.3 

18.3 ± 1.2 

8.21 ± 2.5 

5.68 ± 0.35 

2.47 ± 1.3 

0.971 ± 0.57 

— 

29.0 ± 6.6 

18.9 ± 1.5 

27.4 ± 6.1 

12.2 ± 4.7 

6.26 ± 5.8 

3.08 ± 1.8 

— 

46.6 ± 13 

88.2 ± 28 

65.3 ± 12 

20.5 ± 9.1 

18.7 ± 9.1 

11.1 ± 9.0 

a Data are given in μg/mL as mean ± standard deviation. b Values were below the experimental limit of quantitation (0.103 μg/mL). 

Plasma analyses were not performed on core study vehicle control animals. d n=5; these animals were not dosed on the day of blood collection. e n=2; no statistical analyses performed 

c 
309 

APPENDIX O
 

CHEMICAL CHARACTERIZATION
 

AND DOSE FORMULATION STUDIES
 

PROCUREMENT AND CHARACTERIZATION ........................................... 310
 

PREPARATION AND ANALYSIS OF DOSE FORMULATIONS .................................. 313
 

FIGURE O1 Infrared Absorption Spectrum of AZT ................................... 315
 

FIGURE O2 Nuclear Magnetic Resonance Spectrum of AZT ............................. 316
 

TABLE O1 Results of Analyses for Vesicular Stomatitis Virus Activities of "-Interferon A/D 

and "-Interferon A Bulk Chemicals in the 2-Year Gavage Studies 

of AZT and "-Interferon A/D ......................................... 317
 

TABLE O2 Preparation and Storage of Dose Formulations in the Gavage Studies 

of AZT and "-Interferon A/D ......................................... 322
 

TABLE O3 Results of Analyses of Dose Formulations Administered to Mice 

in the 14-Week Gavage Study of AZT .................................... 323
 

TABLE O4 Results of Analyses of AZT Dose Formulations Administered to Mice
 

in the 2-Year Gavage Studies of AZT and AZT/"-Interferon A/D ................. 324
 
310 AZT and AZT/"-Interferon A/D, NTP TR 469 

CHEMICAL CHARACTERIZATION 

AND DOSE FORMULATION STUDIES 

PROCUREMENT AND CHARACTERIZATION 

AZT 

3N-Azido-3N-deoxythymidine (AZT) was obtained from the Burroughs Wellcome Company (Research 

Triangle Park, NC) in three lots (809796, 80/0557-130-B, and 86/5082-184). Lot 809796 was used during 

the 14-week study and 2-year AZT and AZT/"-interferon A/D studies, and lots 80/0557-130-B and 

86/5082-184 were used during the 2-year AZT and AZT/"-interferon A/D studies. Identity, purity, and 

stability analyses were conducted by the analytical chemistry laboratory, Midwest Research Institute (Kansas 

City, MO). Reports on analyses performed in support of the AZT and AZT/"-interferon A/D studies are on 

file at the National Institute of Environmental Health Sciences (NIEHS). 

All lots of the chemical, a white to slightly off-white fine powder, were identified as AZT by infrared 

spectroscopy. Lots 809796 and 80/0557-130-B were also identified by ultraviolet/visible and nuclear 

magnetic resonance spectroscopy. All spectra were consistent with the literature spectra (Horwitz et al., 

1964; SRI, 1987) of AZT. The infrared and nuclear magnetic spectra are presented in Figures O1 and O2. 

The melting point ranges of lots 809796 and 80/0557-130-B were 123.5E to 124.5E C and 121.5E to 

123.5E C, respectively, and were consistent with a literature reference (Horwitz et al., 1964). For 

lot 809796, the optical rotation value was ["]D

21=+46.6E ± 0.2E, which was not consistent with 

information from the manufacturer or a literature reference (Horwitz et al., 1964) but was consistent 

with values determined by the study laboratory (SRI, 1987). An additional determination of the 

optical rotation value for lot 809796 under conditions described by the supplier indicated a value of 

["]D

25=+60.9E ± 0.3E, which was consistent with the value reported by the supplier. For 

lot 80/0557-130-B, the optical rotation value of ["]D

25=+61.5E ± 0.4E was consistent with the results from 

the second determination for lot 809796. For lot 80/0557-130-B, the partition coefficient between octanol 

and pH 7.4 phosphate buffer was determined to be 0.05 at room temperature, and the maximum solubility 

in water at 25E C was determined to be 22.8 mg/mL. 

The purities of lots 809796 and 80/0557-130-B were determined using elemental analyses, Karl Fischer 

water analysis, functional group titration, thin-layer chromatography (TLC), and high-performance liquid 

chromatography (HPLC). For functional group titration, the samples were dissolved in pyridine and then 

titrated with 0.1 N tetrabutylammonium hydroxide in isopropanol to a potentiometric endpoint. The 

titration was monitored with a glass indicating electrode and a calomel reference electrode filled with 1 M 

methanolic (lot 809796) tetrabutylammonium chloride. TLC was performed on Silica Gel 60A K6F plates 

(lot 809796) or Whatman Silica Gel 60A F-254 plates (lot 80/0557-130-B) with two solvent systems: 

1) methanol:ethyl acetate (50:50) and 2) toluene:ethanol (90:10). The plates were examined under 

ultraviolet light (254 nm) with a spray prepared by dissolving 0.5 g potassium permanganate in 100 mL of 

1 N sodium hydroxide. After spraying, the plates were heated at 100E C for 2 to 3 minutes (lot 809796) or 

at 110E C for 1 minute (lot 80/0557-130-B). p-Acetophenetidide was used as a reference standard. For 

lot 809796, HPLC was performed with a Phenomenex Spherex ODS column with ultraviolet detection 

(254 nm) and a solvent system of water:methanol (82:18). For lot 80/0557-130-B, HPLC was performed 

with a Regis Val-U-Pak HP column with ultraviolet detection (254 nm) and a solvent system of 

water:methanol (80:20). For each lot, the flow rate was 1.0 mL/minute. 

For lot 809796, elemental analyses for carbon, hydrogen, and nitrogen were in agreement with the 

theoretical values for AZT. Karl Fischer water analysis indicated 0.10% ± 0.03% water. Functional 

group titration indicated a purity of 101.4% ± 0.5%. TLC by system 1 indicated a major spot and a trace 

impurity; TLC by system 2 indicated a major spot and a minor impurity. HPLC indicated one major peak 
AZT and AZT/"-Interferon A/D, NTP TR 469 311 

and two impurities with a combined area of 1.8% relative to the major peak area. One of these impurities 

was identified as thymine from an ultraviolet spectrum (190 nm to 350 nm range) obtained with a diode 

array detector, and the thymine content was estimated to be 0.80% ± 0.01% with the same HPLC system 

as used for the purity analysis of lot 809796 but with a Burdick and Jackson OD5 C18 column, a solvent 

ratio of 90:10, and uracil as the internal standard. The overall purity of lot 809796 was determined to be 

approximately 98%. 

For lot 80/0557-130-B, elemental analyses for carbon, hydrogen, and nitrogen were in agreement with the 

theoretical values for AZT. Karl Fischer water analysis indicated 0.04% ± 0.01% water. Functional 

group titration indicated a purity of 102.1% ± 0.5%. TLC by each system indicated a major spot and a 

trace impurity. HPLC indicated one major peak and two impurities with a combined area of 1.6% relative 

to the major peak area. A concomitant analysis of lot 80/0557-130-B with lot 809786 was performed using 

the HPLC system used for the purity analysis of lot 80/0557-130-B but with a Burdick and Jackson OD5 

C18 column, a solvent ratio of 75:25, and an internal standard of (-)-6-methylaminopurine riboside. Major 

peak comparisons of lot 80/0557-130-B with lot 809796 indicated a purity of 100.3% ± 0.9% for 

lot 80/0557-130-B relative to lot 809796. The overall purity of lot 80/0557-130-B was determined to be 

approximately 98%. 

The purity of lot 86/5082-184 relative to that of lot 80/0557-130-B was determined by the study laboratory 

using HPLC. HPLC was performed with a Burdick and Jackson OD5 C18 column with ultraviolet detection 

(254 nm) and a solvent system of 0.005 M triethanolamine in water:methanol (70:30) adjusted to pH 7 with 

phosphoric acid. The flow rate was 1.0 mL/minute, and (-)-6-methylaminopurine riboside was the internal 

standard. The purity of lot 86/5082-184 relative to lot 80/0557-130-B was determined to be approximately 

102%. 

Accelerated stability studies of lot 809796 of the bulk chemical were performed by the analytical chemistry 

laboratory. HPLC was performed with the same system used for the major peak comparisons of 

lot 80/0557-130-B with lot 809796. These studies indicated that AZT was stable as a bulk chemical for 

2 weeks when stored protected from light at temperatures up to 60E C. To ensure stability, the bulk 

chemical was stored in the original container (double plastic bags inside a metal can) in the dark at room 

temperature (approximately 22E C) for 2 months after receipt before the 14-week study began and at 

approximately !20E C thereafter. Stability was monitored during the 14-week and 2-year studies using 

HPLC. No degradation of the bulk chemical was detected. 

Methylcellulose 

Methylcellulose was obtained from Fisher Scientific Company (Pittsburgh, PA) in one lot (876672), which 

was used during the 14-week study, the 2-year AZT study, and the 2-year AZT/"-interferon A/D studies. 

Identity, purity, and stability analyses were conducted by the analytical chemistry laboratory. 

The chemical, a white powder, was identified as methylcellulose by infrared, ultraviolet/visible, and nuclear 

magnetic resonance spectroscopy. All spectra were consistent with those expected for the structure of 

methylcellulose. The infrared spectrum was consistent with the literature spectrum (Sadtler Standard 

Spectra) of methylcellulose. No melting point was observed up to 300E C; the sample decomposed at 250E 

to 300E C. 

The purity of lot 876672 was determined by elemental analyses, Karl Fischer water analysis, functional 

group titration, and HPLC. The methoxy group content was estimated from the nuclear magnetic resonance 

spectrum. United States Pharmacopeia (USP) XXI analyses for the identification, apparent viscosity, weight 

loss on drying, residue on ignition, arsenic content, heavy metal content, and percent methoxy content were 

also performed. For functional group titration, a methoxy group determination was performed by Galbraith 

Laboratories, Inc. (Knoxville, TN). HPLC was performed with a Toyo Soda TSK G4000 SW column with 
312 AZT and AZT/"-Interferon A/D, NTP TR 469 

refractive index detection and a solvent system of 0.005 M sodium dodecyl sulfate in water. The flow rate 

was 1.0 mL/minute. 

Elemental analyses for carbon and hydrogen were in agreement with the theoretical values for 

methylcellulose based on 1.8 degrees of substitution and corrected for 1.94% water. In addition, elemental 

analyses indicated 0.058% sodium. Karl Fischer water analysis indicated 1.94% ± 0.03% water. 

Functional group titration indicated 30.62% ± 0.08% methoxy group content; this value is consistent with 

the theoretical value, assuming 1.8 degrees of substitution (30.4%), and with the estimate of the methoxy 

group content from the nuclear magnetic spectrum (31.7%). The complete battery of USP tests for 

methylcellulose indicated the following results: the chemical was identified as methylcellulose; the apparent 

viscosity was 3,749 to 4,060 cP; the weight loss on drying was 1.9% ± 0.3%; the residue on ignition was 

less than 0.3%; the tests for arsenic and heavy metals were passed; and the methoxy group content was 

30.3% ± 0.2% for lot 876672 and 28.3% ± 0.0% for the USP reference material. The chemical met the 

USP specifications for methylcellulose for all analyses. HPLC indicated one major peak and no impurities 

with areas greater than or equal to 0.1% relative to the major peak area. Cumulative analytical data 

indicated that lot 876672 of methylcellulose was suitable for use as a dosing vehicle. 

Accelerated stability studies of the bulk chemical were performed by the analytical chemistry laboratory. 

Gas chromatography (USP XXI method) was performed to determine the methoxy group content using 

thermal conductivity detection with a helium carrier gas at a flow rate of 20 mL/minute, a 10% SP-2100 on 

100/120 Chromosorb WHP glass column, an isothermal oven temperature of 100E C, and toluene as the 

internal standard. These studies indicated that methylcellulose was stable as a bulk chemical for 3 weeks 

when stored protected from light at temperatures up to 60E C. To ensure stability, the bulk chemical was 

stored in the original containers in the dark at room temperature. Stability was monitored by Galbraith 

Laboratories, Inc., during the 14-week and 2-year studies using gas chromatography to determine methoxy 

group content. Results of duplicate analyses were all within the required range of 27.5% to 31.5% methoxy 

group content. No degradation of the bulk chemical was detected. 

"-Interferon A/D and "-Interferon A 

"-Interferon A/D and "-interferon A were obtained from Hoffman-La Roche (Nutley, NJ). 

"-Interferon A/D was obtained in one lot (1084), which was used during the 2-year "-interferon A/D and
 

AZT/"-interferon A/D studies. "-Interferon A was obtained in one lot (019116), which was used during
 

the 2-year "-interferon A/D study. Antiviral activity assays were conducted by the study laboratory. 

Information from the manufacturer indicated a protein concentration of 2.8 mg/mL and a bulk activity of
 8 1.5 × 10 U/mL for lot 1084 of "-interferon A/D and a protein concentration of 5.47 mg/mL and a bulk 9 activity of 1.095 × 10 U/mL for lot 019116 of "-interferon A. The bulk chemical was stored in the 

original containers (plastic bottles) at approximately !20E C from receipt until 2 weeks before the 2-year 

studies began and at !140E or !180E C in the vapor phase of a liquid nitrogen cryopreservation vat 

thereafter. 

Each lot of the "-interferon A/D and "-interferon A bulk chemicals was measured for vesicular stomatitis 

virus (VSV) antiviral activity (Table O1). The antiviral activities (titers) of "-interferon A/D and 

"-interferon A were determined with the viral cytopathic effect assay as follows: Alex Chang 

Hypernephroma cells in RPMI 1640 medium, supplemented with 10% fetal bovine serum and 2 mM 

5 glutamine, were seeded into the wells of a 96-well microtiter plate at a density of 1 × 10 cells/well. 

Samples of interferon were then added in dilution series, and the plate was incubated at 37E ± 1E C under 

5% carbon dioxide for 24 hours. A predetermined quantity of VSV was then added to each well, and the 

incubation was continued for an additional 24 hours or until a cytopathic effect, as evidenced by cell lysis, 

was clearly evident in the virus control wells (cells + virus, no added interferon). Neutral red dye was then 

added to each well, and the plate was incubated another hour during which cells that survived the viral 
AZT and AZT/"-Interferon A/D, NTP TR 469 313 

challenge took up dye, while dead or lysed cells did not. The dye solution along with the nonadherent and 

dead cells and cell debris were removed by careful washing with 0.85% sodium chloride, and the neutral 

red taken up by surviving cells was extracted by adding 100 μL of 50% ethanol in 0.1 M phosphate buffer 

to each well. The absorbance at 550 nm was recorded for each well and entered into a computer, which 

transformed the data into a titration curve (percent control absorption at 550 nm versus interferon dilution) 

and calculated the dilution of interferon that conferred 50% protection (50% of the control value) against 

viral challenge. The reciprocal of this dilution was multiplied by any previous dilutions to yield the actual 

titer of the interferon in laboratory units, which were converted to international units using a correction 

factor determined by calibrating the "-interferon A/D and "-interferon A laboratory standards with an 

international standard of interferon of known titer. In these studies, an international standard preparation of 

" 2-interferon obtained from the National Institute of Allergy and Infectious Diseases was used to calibrate 

the reference standards of "-interferon A/D and "-interferon A used for preparation of dose formulations 

and routine analysis. Complete details of the procedures used and the results are on file at NIEHS. 

PREPARATION AND ANALYSIS OF DOSE FORMULATIONS 

AZT 

The dosing vehicle was prepared by mixing methylcellulose with heated deionized water and then diluting 

with water to form a 0.5% solution, which was allowed to cool. AZT was then mixed with the dosing 

vehicle until a homogeneous suspension was obtained to give the required concentrations (Table O2). The 

dose formulations were stored at room temperature (at the beginning of the 14-week study) or refrigerated at 

approximately 5E C in amber glass bottles in the dark for up to 20 days. 

Homogeneity studies of a 200 mg/g solution of lot 809796 were performed by the analytical chemistry 

laboratory using HPLC with the same system used for the purity analysis of lot 86/5082-184 but with a 

solvent system of 0.005 M triethanolamine in water:methanol (80:20). Stability studies of a 2 mg/g solution 

were also performed using the same HPLC system. Homogeneity was confirmed, and the stability of the 

solution was confirmed for 3 weeks at room temperature when stored in the dark and for 3 hours when open 

to air and light. 

Periodic analyses of the dose formulations of AZT were conducted at the study laboratory using HPLC. 

For the 14-week study, the formulations were analyzed every 4 to 8 weeks (Table O3). During the 2-year 

studies, the formulations were analyzed every 4 to 8 weeks (Table O4). All of the dose formulations 

analyzed and used during the 14-week study were within 10% of the target concentrations. All of the dose 

formulations analyzed and used during the 2-year AZT and AZT/"-interferon A/D studies were within 

10% of the target concentrations. All of the animal room samples were also within 10% of the target 

concentrations. 

"-Interferon A/D and "-Interferon A 

The dosing vehicle was prepared by aseptically mixing sterile C57Bl/6 mouse serum (Harlan SpragueDawley, Inc., Indianapolis, IN) in Earle’s Balanced Salt Solution (Grand Island Biologicals Co.) to achieve 

a 10% solution. The vehicle was adjusted to a pH of approximately 7.2. Based on titers determined for the 

bulk chemicals, dose formulations were prepared by dilution of the stock solution. Therefore, the same 

amount (quantity of pure recombinant protein) of "-interferon A/D or "-interferon A was administered to 

the animals throughout the 2-year studies. "-Interferon A/D and "-interferon A were thawed at room 

temperature, and serial dilutions were prepared in the vehicle under sterile conditions using sterile pipettes 

and a calibrated Matrix Electropette (Table O2). The dose formulations were stored in sterile, 

Teflon®-capped, brown glass dosing vials at 4E C. Samples for antiviral activity assays were stored at 

!140E C or cryopreserved in liquid nitrogen. 
314 AZT and AZT/"-Interferon A/D, NTP TR 469 

Sterility of the dose preparations was monitored with a 2-week incubation in both Sabouraud’s broth and 

thioglycollate broth at 37E C followed by a visual examination for microbial growth. Stability of 

"-interferon A/D and "-interferon A dose formulations had been previously established for 42 days. 

Periodic analyses of the antiviral activity of the dose formulations of "-interferon A/D and "-interferon A 

were conducted at the study laboratory using the same methods as for the bulk chemicals. These analyses 

demonstrated that interferon dose formulations used in the studies retained antiviral activity under normal 

dosing conditions. However, the differences between the titers of dose formulations determined by the 

cytopathic effect assay (observed) and the titers expected from making known dilutions of the calibrated 

laboratory standards (theoretical) were consistently greater than 10%. Because of this variability and the 

demonstrated stability of antiviral activity under dosing conditions, routine analysis of interferon dose 

formulations by the cytopathic effect assay was discontinued in October 1991. The long-term stability of 

laboratory standards from which dose formulations were prepared was confirmed with the cytopathic effect 

assay in March 1993. 
AZT and AZT/"-Interferon A/D, NTP TR 469
 315 

FIGURE O1 

Infrared Absorption Spectrum of AZT 
316 AZT and AZT/"-Interferon A/D, NTP TR 469
 

FIGURE O2 

Nuclear Magnetic Resonance Spectrum of AZT 
AZT and AZT/"-Interferon A/D, NTP TR 469 317 

TABLE O1 

Results of Analyses for Vesicular Stomatitis Virus Activities of "-Interferon A/D 

and "-Interferon A Bulk Chemicals in the 2-Year Gavage Studies of AZT and "-Interferon A/D 
318 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE O1 

Results of Analyses for Vesicular Stomatitis Virus Activities of "-Interferon A/D 

and "-Interferon A Bulk Chemicals in the 2-Year Gavage Studies of AZT and "-Interferon A/D 
AZT and AZT/"-Interferon A/D, NTP TR 469 319 

TABLE O1 

Results of Analyses for Vesicular Stomatitis Virus Activities of "-Interferon A/D 

and "-Interferon A Bulk Chemicals in the 2-Year Gavage Studies of AZT and "-Interferon A/D 
320 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE O1 

Results of Analyses for Vesicular Stomatitis Virus Activities of "-Interferon A/D 

and "-Interferon A Bulk Chemicals in the 2-Year Gavage Studies of AZT and "-Interferon A/D 
AZT and AZT/"-Interferon A/D, NTP TR 469 321 

TABLE O1 

Results of Analyses for Vesicular Stomatitis Virus Activities of "-Interferon A/D 

and "-Interferon A Bulk Chemicals in the 2-Year Gavage Studies of AZT and "-Interferon A/D 
322 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE O2 

Preparation and Storage of Dose Formulations in the Gavage Studies of AZT and "-Interferon A/D 

14-Week Study	 2-Year Studies 

Preparation 

The dosing vehicle was prepared by mixing methylcellulose with AZT: Same as 14-week study 

heated deionized water and then diluting with water to form a "-Interferon A/D and "-interferon A: Interferon was diluted with 

0.5% solution, which was allowed to cool. AZT was added to the the dosing vehicle (Earle’s Balanced Salt Solution, pH 7.2, with 

required amount of vehicle and stirred with a magnetic stirrer until 10% mouse serum) to the desired concentrations. 

a homogeneous preparation was obtained. Doses were prepared 

every 2 weeks. 

Chemical Lot Number 

AZT: 809796	 AZT: 809796, 80/0557-130-B, 86/5082-184 

Methylcellulose: 876672	 Methylcellulose: 876672 

"-Interferon A/D: 1084 

"-Interferon A: 019116 

Maximum Storage Time 

20 days	 AZT: 20 days 

"-Interferon A/D and "-interferon A: 42 days 

Storage Conditions 

Stored in amber glass bottles in the dark at room temperature or	 AZT: Stored in amber glass bottles in the dark and refrigerated at 

refrigerated at approximately 5E C	 approximately 5E C 

"-Interferon A/D and "-interferon A: Stored in Teflon®-capped 

brown glass vials at approximately 4E C 

Study Laboratory 

Southern Research Institute Southern Research Institute 

(Birmingham, AL) (Birmingham, AL) 
AZT and AZT/"-Interferon A/D, NTP TR 469 323 

TABLE O3 

Results of Analyses of Dose Formulations Administered to Mice in the 14-Week Gavage Study of AZT 

Target Determined Difference a Date Prepared Date Analyzed Concentration Concentration from Target 

(mg/g) (mg/g) (%) 

b 27 March 1989 28 March 1989 1.25 1.26 +1 

b 1.25 1.24 !1 

b 1.25 1.24 !1 

1.25 1.24 !1 

2.50 2.54 +2 

5.00 5.05 +1 

20.0 19.2 !4 

50.0 48.8 !2 

22 May 1989 23-24 May 1989 1.25 1.28 +2 

2.50 2.41 !4 

5.00 5.08 +2 

20.0 20.2 +1 

50.0 52.8 +6 

3 July 1989 5 July 1989 1.25 1.12 !10 

2.50 2.42 !3 

5.00 4.99 0 

20.0 20.0 0 

50.0 50.4 +1 

a Results of duplicate analyses. Dosing volume=20 mL/kg; 1.25 mg/g=25 mg/kg, 2.50 mg/g=50 mg/kg, 5.00 mg/g=100 mg/kg, 

20.0 mg/g=400 mg/kg, 50.0 mg/g=1,000 mg/kg. b Homogeneity analyses; not used for dosing 
324 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE O4 

Results of Analyses of AZT Dose Formulations Administered to Mice in the 2-Year Gavage Studies 

of AZT and AZT/"-Interferon A/D 

Target Determined Difference a Date Prepared Date Analyzed Concentration Concentration from Target 

(mg/g) (mg/g) (%) 

29 June 1990 2 July 1990 1.50 1.44 !4 

3.00 2.90 !3 

6.00 5.87 !2 

20 July 1990b 1.50 1.49 !1 

3.00 3.06 +2 

6.00 6.09 +2 

24 August 1990 24 August 1990 1.50 1.47 !2 

3.00 3.03 +1 

6.00 6.01 0 

21 September 1990 10-11 October 1990 1.50 1.50 0 

3.00 3.03 +1 

6.00 5.87 !2 

b 10-11 October 1990 1.50 1.50 0 

3.00 3.03 +1 

6.00 6.16 +3 

30 November 1990 3 December 1990 1.50 1.46 !3 

3.00 3.12 +4 

6.00 5.96 !1 

28 December 1990 4 January 1991 1.50 1.51 +1 

3.00 2.98 !1 

6.00 6.06 +1 

21-22 January 1991b 1.50 1.53 +2 

3.00 3.02 +1 

6.00 6.01 0 

22 February 1991 25 February 1991 1.50 1.55 +3 

1.50 1.55 +3 

3.00 3.07 +2 

3.00 3.04 +1 

6.00 6.05 +1 

6.00 6.00 0 

8 March 1991 28 March 1991 1.50 1.48 !1 

3.00 3.04 +1 

6.00 6.15 +3 

19 April 1991 22 April 1991 1.50 1.39 !7 

1.50 1.42 !5 

3.00 2.95 !2 

3.00 3.10 +3 

6.00 6.02 0 

6.00 6.31 +5 
AZT and AZT/"-Interferon A/D, NTP TR 469 325 

TABLE O4 

Results of Analyses of AZT Dose Formulations Administered to Mice in the 2-Year Gavage Studies 

of AZT and AZT/"-Interferon A/D 

Target Determined Difference 

Date Prepared Date Analyzed Concentration Concentration from Target 

(mg/g) (mg/g) (%) 

14 June 1991 17 June 1991 1.50 1.45 !3 

1.50 1.44 !4 

3.00 2.96 !1 

3.00 2.99 0 

6.00 5.93 !1 

6.00 6.04 +1 

8 July 1991b 1.50 1.51 +1 

1.50 1.51 +1 

3.00 2.90 !3 

3.00 3.02 +1 

6.00 5.80 !3 

6.00 6.03 +1 

9 August 1991 13 August 1991 1.50 1.49 !1 

1.50 1.49 !1 

3.00 3.01 0 

3.00 3.02 +1 

6.00 6.04 +1 

6.00 6.00 0 

4 October 1991 7-8 October 1991 1.50 1.47 !2 

1.50 1.48 !1 

3.00 2.97 !1 

3.00 2.97 !1 

6.00 5.92 !1 

6.00 5.97 !1 

2 December 1991 2-3 December 1991 1.50 1.55 +3 

1.50 1.55 +3 

3.00 3.02 +1 

3.00 3.03 +1 

6.00 6.05 +1 

6.00 6.03 +1 

b 20 December 1991 1.50 1.51 +1 

1.50 1.51 +1 

3.00 3.05 +2 

3.00 3.05 +2 

6.00 6.08 +1 

6.00 6.00 0 

24 January 1992 27 January 1992 1.50 1.47 !2 

1.50 1.48 !1 

3.00 3.01 0 

3.00 3.02 +1 

6.00 6.10 +2 

6.00 6.05 +1 

20 March 1992 23-24 March 1992 1.50 1.50 0 

1.50 1.48 !1 

3.00 2.91 !3 

3.00 2.96 !1 

6.00 5.86 !2 

6.00 5.89 !2 
326 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE O4 

Results of Analyses of AZT Dose Formulations Administered to Mice in the 2-Year Gavage Studies 

of AZT and AZT/"-Interferon A/D 

Target Determined Difference 

Date Prepared Date Analyzed Concentration Concentration from Target 

(mg/g) (mg/g) (%) 

18 May 1992 18-19 May 1992 1.50 1.55 +3 

1.50 1.47 !2 

3.00 2.97 !1 

3.00 3.00 0 

6.00 5.98 0 

6.00 6.01 0 

b 5 June 1992 1.50 1.49 !1 

1.50 1.50 0 

3.00 2.99 0 

3.00 3.01 0 

6.00 5.96 !1 

6.00 5.94 !1 

26 June 1992 29 June 1992 1.50 1.53 +2 

3.00 2.96 !1 

6.00 5.95 !1 

17 & 21 July 1992b 1.50 1.49 !1 

3.00 3.03 +1 

6.00 6.06 +1 

21 August 1992 24 August 1992 1.50 1.47 !2 

3.00 2.98 !1 

6.00 5.89 !2 

18 September 1992 21 September 1992 1.50 1.53 +2 

3.00 3.01 0 

6.00 5.94 !1 

b 9 October 1992 1.50 1.50 0 

3.00 3.02 +1 

6.00 6.08 +1 

13 November 1992 16 November 1992 1.50 1.49 !1 

3.00 3.00 0 

6.00 6.01 0 

a Results of duplicate analyses. Dosing volume=10 mL/kg; 1.50 mg/g=15 mg/kg, 3.00 mg/g=30 mg/kg, 6.00 mg/g=60 mg/kg. b Animal room samples 
327 

APPENDIX P 

INGREDIENTS, NUTRIENT COMPOSITION, 

AND CONTAMINANT LEVELS 

IN NIH-07 RAT AND MOUSE RATION 

TABLE P1 

TABLE P2 

TABLE P3 

TABLE P4 

Ingredients of NIH-07 Rat and Mouse Ration .............................. 

Vitamins and Minerals in NIH-07 Rat and Mouse Ration ...................... 

Nutrient Composition of NIH-07 Rat and Mouse Ration ...................... 

Contaminant Levels in NIH-07 Rat and Mouse Ration ........................ 

328 

328 

329 

330 
328 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE P1 

Ingredients of NIH-07 Rat and Mouse Rationa 

Ingredientsb Percent by Weight 

Ground #2 yellow shelled corn 24.50 

Ground hard winter wheat 23.00 

Soybean meal (49% protein) 12.00 

Fish meal (60% protein) 10.00 

Wheat middlings 10.00 

Dried skim milk 5.00 

Alfalfa meal (dehydrated, 17% protein) 4.00 

Corn gluten meal (60% protein) 3.00 

Soy oil 2.50 

Dried brewer’s yeast 2.00 

Dry molasses 1.50 

Dicalcium phosphate 1.25 

Ground limestone 0.50 

Salt 0.50 

Premixes (vitamin and mineral) 0.25 

a NCI, 1976; NIH, 1978 b Ingredients were ground to pass through a U.S. Standard Screen No. 16 before being mixed. 

TABLE P2 

Vitamins and Minerals in NIH-07 Rat and Mouse Rationa 

Amount Source 

Vitamins 

A 5,500,000 IU Stabilized vitamin A palmitate or acetate 

D3 4,600,000 IU D-activated animal sterol 

K3 2.8 g Menadione 

d-"-Tocopheryl acetate 20,000 IU 

Choline 560.0 g Choline chloride 

Folic acid 2.2 g 

Niacin 30.0 g 

d-Pantothenic acid 18.0 g d-Calcium pantothenate 

Riboflavin 3.4 g 

Thiamine 10.0 g Thiamine mononitrate 

B12 4,000 μg 

Pyridoxine 1.7 g Pyridoxine hydrochloride 

Biotin 140.0 mg d-Biotin 

Minerals 

Iron 120.0 g Iron sulfate 

Manganese 60.0 g Manganous oxide 

Zinc 16.0 g Zinc oxide 

Copper 4.0 g Copper sulfate 

Iodine 1.4 g Calcium iodate 

Cobalt 0.4 g Cobalt carbonate 

a Per ton (2,000 lb) of finished product 
AZT and AZT/"-Interferon A/D, NTP TR 469 329 

TABLE P3 

Nutrient Composition of NIH-07 Rat and Mouse Ration 

Mean ± Standard 

Nutrient Deviation Range Number of Samples 

Protein (% by weight) 23.45 ± 0.52 22.2 – 24.3 31 

Crude fat (% by weight) 5.33 ± 0.19 5.00 – 5.90 31 

Crude fiber (% by weight) 3.40 ± 0.34 2.60 – 4.30 31 

Ash (% by weight) 6.41 ± 0.19 6.11 – 6.81 31 

Amino Acids (% of total diet) 

Arginine 1.280 ± 0.083 1.110 – 1.390 11 

Cystine 0.308 ± 0.071 0.181 – 0.400 11 

Glycine 1.158 ± 0.048 1.060 – 1.220 11 

Histidine 0.584 ± 0.027 0.531 – 0.630 11 

Isoleucine 0.917 ± 0.033 0.867 – 0.965 11 

Leucine 1.975 ± 0.051 1.850 – 2.040 11 

Lysine 1.274 ± 0.049 1.200 – 1.370 11 

Methionine 0.437 ± 0.109 0.306 – 0.699 11 

Phenylalanine 0.999 ± 0.120 0.665 – 1.110 11 

Threonine 0.904 ± 0.058 0.824 – 0.985 11 

Tryptophan 0.218 ± 0.153 0.107 – 0.671 11 

Tyrosine 0.685 ± 0.094 0.564 – 0.794 11 

Valine 1.086 ± 0.055 0.962 – 1.170 11 

Essential Fatty Acids (% of total diet) 

Linoleic 2.407 ± 0.227 1.830 – 2.570 10 

Linolenic 0.259 ± 0.065 0.100 – 0.320 10 

Vitamins 

Vitamin A (IU/kg) 6,641 ± 1,207 5,510 – 11,450 31 

Vitamin D (IU/kg) 4,450 ± 1,382 3,000 – 6,300 4 

"-Tocopherol (ppm) 35.43 ± 8.98 22.5 – 48.9 11 

Thiamine (ppm) 17.71 ± 2.07 14.0 – 22.0 31 

Riboflavin (ppm) 7.83 ± 0.923 6.10 – 9.00 11 

Niacin (ppm) 99.22 ± 24.27 65.0 – 150.0 11 

Pantothenic acid (ppm) 30.55 ± 3.52 23.0 – 34.6 11 

Pyridoxine (ppm) 9.11 ± 2.53 5.60 – 14.0 11 

Folic acid (ppm) 2.46 ± 0.63 1.80 – 3.70 11 

Biotin (ppm) 0.268 ± 0.047 0.190 – 0.354 11 

Vitamin B (ppb) 40.5 ± 19.1 10.6 – 65.0 11 12 

Choline (ppm) 2,991 ± 382 2,300 – 3,430 10 

Minerals 

Calcium (%) 1.16 ± 0.09 1.00 – 1.49 31 

Phosphorus (%) 0.92 ± 0.04 0.76 – 1.00 31 

Potassium (%) 0.886 ± 0.063 0.772 – 0.971 9 

Chloride (%) 0.529 ± 0.087 0.380 – 0.635 9 

Sodium (%) 0.316 ± 0.033 0.258 – 0.371 11 

Magnesium (%) 0.166 ± 0.010 0.148 – 0.181 11 

Sulfur (%) 0.272 ± 0.059 0.208 – 0.420 10 

Iron (ppm) 350.5 ± 87.3 255.0 – 523.0 11 

Manganese (ppm) 92.48 ± 5.14 81.7 – 99.4 11 

Zinc (ppm) 59.33 ± 10.2 46.1 – 81.6 11 

Copper (ppm) 11.81 ± 2.50 8.09 – 15.4 11 

Iodine (ppm) 3.54 ± 1.19 1.52 – 5.83 10 

Chromium (ppm) 1.66 ± 0.46 0.85 – 2.09 11 

Cobalt (ppm) 0.76 ± 0.23 0.49 – 1.15 7 
330 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE P4 

Contaminant Levels in NIH-07 Rat and Mouse Rationa 

Mean ± Standard 

Deviationb Range Number of Samples 

Contaminants 

Arsenic (ppm) 0.43 ± 0.20 0.10 – 0.70 31 

Cadmium (ppm) 0.11 ± 0.07 0.04 – 0.20 31 

Lead (ppm) 0.34 ± 0.22 0.10 – 1.00 31 c Mercury (ppm) 0.02 0.02 – 0.03 31 

Selenium (ppm) 0.34 ± 0.11 0.05 – 0.60 31 

Aflatoxins (ppb) <5.0 31 

Nitrate nitrogen (ppm)d 9.22 ± 5.09 2.90 – 21.0 31 

Nitrite nitrogen (ppm)d 0.18 ± 0.12 0.10 – 0.70 31 e BHA (ppm)	 2.35 ± 3.72 1.00 – 20.0 31 e BHT (ppm) 1.52 ± 1.43 1.0 – 8.00 31 

Aerobic plate count (CFU/g) 84,481 ± 147,567 4,100 – 710,000 31 

Coliform (MPN/g) 3 ± 0.2 3 – 4 31 

Escherichia coli (MPN/g) <3 31 

Salmonella (MPN/g) Negative 31 

Total nitrosoamines (ppb)f 7.51 ± 1.86 4.70 – 11.40 31 

N-Nitrosodimethylamine (ppb)f 5.42 ± 1.14 2.90 – 8.20 31 

N-Nitrosopyrrolidine (ppb)f 2.08 ± 1.24 1.00 – 6.00 31 

Pesticides (ppm) 

"-BHC <0.01 31 

-BHC <0.02 31 

-BHC <0.01 31 

-BHC <0.01 31 

Heptachlor <0.01 31 

Aldrin <0.01 31 

Heptachlor epoxide <0.01 31 

DDE <0.01 31 

DDD <0.01 31 

DDT <0.01 31 

HCB <0.01 31 

Mirex <0.01 31 

Methoxychlor <0.05 31 

Dieldrin <0.01 31 

Endrin <0.01 31 

Telodrin <0.01 31 

Chlordane <0.05 31 

Toxaphene <0.10 31 

Estimated PCBs <0.20 31 

Ronnel <0.01 31 

Ethion <0.02 31 

Trithion <0.05 31 

Diazinon <0.10 31 

Methyl parathion <0.02 31 

Ethyl parathion <0.02 31 

Malathion 0.20 ± 0.21 0.05 – 0.97 31 

Endosulfan I <0.01 31 

Endosulfan II <0.01 31 

Endosulfan sulfate <0.03 31 

a CFU = colony forming units; MPN = most probable number; BHC = hexachlorocyclohexane or benzene hexachloride b	 For values less than the limit of detection, the detection limit is given as the mean. 

All values except for the September, November, and December 1991 milling dates were less than the detection limit. The detection limit is 

given as the mean. d	 Sources of contamination: alfalfa, grains, and fish meal e Sources of contamination: soy oil and fish meal f All values were corrected for percent recovery. 

c 
331 

APPENDIX Q 

SENTINEL ANIMAL PROGRAM 

METHODS .............................................................. 

TABLE Q1 Murine Virus Antibody Determinations for Mice in the 14-Week 

and 2-Year Studies of AZT and AZT/"-Interferon A/D ....................... 

332 

335 
332 AZT and AZT/"-Interferon A/D, NTP TR 469 

SENTINEL ANIMAL PROGRAM
 

METHODS 

Rodents used in the Carcinogenesis Program of the National Toxicology Program are produced in optimally 

clean facilities to eliminate potential pathogens that may affect study results. The Sentinel Animal Program 

is part of the periodic monitoring of animal health that occurs during the toxicologic evaluation of chemical 

compounds. Under this program, the disease state of the rodents is monitored via serology on sera from 

extra (sentinel) animals in the study rooms. These animals and the study animals are subject to identical 

environmental conditions. The sentinel animals come from the same production source and weanling 

groups as the animals used for the studies of chemical compounds. 

Serum samples were collected from randomly selected mice during the 14-week and 2-year studies. Blood 

from each animal was collected and allowed to clot, and the serum was separated. The samples were 

processed appropriately and sent to Microbiological Associates, Inc. (Bethesda, MD), for determination of 

antibody titers. The laboratory serology methods and viral agents for which testing was performed are 

tabulated below; the times at which blood was collected during the studies are also listed. 

Method and Test Time of Analysis 

14-Week Study 

ELISA 

Ectromelia virus 

GDVII (mouse encephalomyelitis virus) 

LCM (lymphocytic choriomeningitis virus) 

MVM (minute virus of mice) 

Mouse adenoma virus 

MHV (mouse hepatitis virus) 

Mycoplasma arthritidis 

Mycoplasma pulmonis 

PVM (pneumonia virus of mice) 

Reovirus 3 

Sendai 

Study termination 

Study termination 

Study termination 

Study termination 

Study termination 

Study termination 

Study termination 

Study termination 

Study termination 

Study termination 

Study termination 

Immunofluorescence Assay 

EDIM (epizootic diarrhea of infant mice) 

Reovirus 3 

Study termination 

Study termination (males only) 

Hemagglutination Inhibition 

K (papovavirus) 

Polyoma virus 

Study termination 

Study termination 
AZT and AZT/"-Interferon A/D, NTP TR 469 333 

2-Year AZT Study 

ELISA 

Ectromelia virus 

EDIM 

GDVII 

LCM 

Mouse adenoma virus-FL 

MHV 

M. arthritidis 

M. pulmonis 

PVM
 

Reovirus 3
 

Sendai
 

Immunofluorescence Assay 

Ectromelia virus 

EDIM 

GDVII 

MHV 

Reovirus 3 

Hemagglutination Inhibition 

K 

MVM 

Polyoma virus 

2-Year "-Interferon A/D Study 

ELISA 

Ectromelia virus 

EDIM 

GDVII 

LCM 

Mouse adenoma virus-FL 

MHV 

M. arthritidis 

M. pulmonis 

PVM
 

Reovirus 3
 

Sendai
 

Immunofluorescence Assay 

EDIM 

GDVII 

Mouse adenoma virus-FL 

Reovirus 3 

Hemagglutination Inhibition 

K 

MVM 

Polyoma virus 

7, 12, and 19 months, study termination 

7, 12, and 19 months, study termination 

7, 12, and 19 months, study termination 

7, 12, and 19 months, study termination 

7, 12, and 19 months, study termination 

5, 7, 10, 12, and 19 months, study termination 

19 months and study termination 

19 months and study termination 

7, 12, and 19 months, study termination 

5, 7, 12, and 19 months, study termination 

5, 7, 10, 12, and 19 months, study termination 

19 months 

7, 12, and 19 months 

19 months 

10 months 

5, 7, and 19 months 

7, 12, and 19 months, study termination 

7, 12, and 19 months, study termination 

7, 12, and 19 months, study termination 

7, 13, and 19 months, study termination 

13 and 19 months, study termination 

7, 13, and 19 months, study termination 

7, 13, and 19 months, study termination 

7, 13, and 19 months, study termination 

3, 7, 13, and 19 months, study termination 

Study termination 

Study termination 

7, 13, and 19 months, study termination 

3, 7, 13, and 19 months, study termination 

3, 7, 13, and 19 months, study termination 

7 and 19 months 

19 months 

13 months 

13 months and study termination 

7, 13, and 19 months, study termination 

7, 13, and 19 months, study termination 

7, 13, and 19 months, study termination 
334 AZT and AZT/"-Interferon A/D, NTP TR 469 

2-Year AZT/500 U "-Interferon A/D Study 

ELISA 

Ectromelia virus 7, 8, 12, and 18 months, study termination 

EDIM 12 and 18 months, study termination 

GDVII 7, 8, 12, and 18 months, study termination 

LCM 7, 8, 12, and 18 months, study termination 

Mouse adenoma virus-FL 7, 8, 12, and 18 months, study termination 

MHV 2, 7, 8, 12, and 18 months, study termination 

M. arthritidis 18 months and study termination 

M. pulmonis 18 months and study termination 

PVM 7, 8, 12, and 18 months, study termination 

Reovirus 3 2, 7, 8, 12, and 18 months, study termination 

Sendai 2, 7, 8, 12, and 18 months, study termination 

Immunofluorescence Assay 

EDIM 7, 8, and 18 months, study termination 

GDVII 12 months 

LCM 7 and 18 months 

Mouse adenoma virus-FL 7, 12, and 18 months 

MHV 7 months 

Reovirus 3 2 and 7 months 

Hemagglutination Inhibition 

K 7, 8, 12, and 18 months, study termination 

MVM 7, 8, 12, and 18 months, study termination 

Polyoma virus 7, 8, 12, and 18 months, study termination 

2-Year AZT/5,000 U "-Interferon A/D Study 

ELISA 

Ectromelia virus 6, 12, and 18 months, study termination 

EDIM 6, 12, and 18 months, study termination 

GDVII 6, 12, and 18 months, study termination 

LCM 6, 12, and 18 months, study termination 

Mouse adenoma virus-FL 6, 12, and 18 months, study termination 

MHV 6, 12, and 18 months, study termination 

M. arthritidis 18 months and study termination 

M. pulmonis 18 months and study termination 

PVM 6, 12, and 18 months, study termination 

Reovirus 3 6, 12, and 18 months, study termination 

Sendai 6, 12, and 18 months, study termination 

Immunofluorescence Assay 

EDIM 6 and 12 months, study termination 

GDVII 12 months 

LCM Study termination 

MVM 6 months 

Mouse adenoma virus-FL Study termination 

Reovirus 3 6, 12, and 18 months 
AZT and AZT/"-Interferon A/D, NTP TR 469 335 

2-Year AZT/5,000 U "-Interferon A/D Study (continued) 

Hemagglutination Inhibition 

K 6, 12, and 18 months, study termination 

MVM 6, 12, and 18 months, study termination 

Polyoma virus 6, 12, and 18 months, study termination 

Results of serology tests are presented in Table Q1. 

TABLE Q1 

Murine Virus Antibody Determinations for Mice in the 14-Week and 2-Year Studies 

of AZT and AZT/"-Interferon A/D 

Interval Incidence of Antibody

in Sentinel Animals 

Positive Serologic 

Reaction for 

14-Week Study 

Study termination 1/8 Reovirus 3a 

2-Year Studies 

AZT 

Core Groups 

5 Months 

7 Months 

10 Months 

12 Months 

19 Months 

Study termination 

7/10 

1/10 

6/9 

1/1 

7/10 

5/9 

10/10 

MHV 

Reovirus 3 

MHV 

MHV 

MHV 

MHV 

MHV 

Clinical Pathology Groups 

5 Months 

7 Months 

12 Months 

19 Months 

10/10 

9/9 

3/10 

6/10 

MHV 

MHV 

MHV 

MHV 

"-Interferon A/D 

Core Groups 

3 Months 

7 Months 

13 Months 

19 Months 

Study termination 

6/10 

5/7 

6/8 

7/9 

10/10 

2/10 

1/10 

MHV 

MHV 

MHV 

MHV 

MHV 

M. arthritidisb 

Reovirus 3a 

Clinical Pathology Groups 

3 Months 

7 Months 

13 Months 

19 Months 

8/10 

8/9 

9/10 

8/9 

MHV 

MHV 

MHV 

MHV 
336 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE Q1 

Murine Virus Antibody Determinations for Mice in the 14-Week and 2-Year Studies 

of AZT and AZT/"-Interferon A/D 

Interval Incidence of Antibody

in Sentinel Animals 

Positive Serologic 

Reaction for 

2-Year Studies (continued) 

AZT/500 U "-Interferon A/D 

Core Groups 

2 Months 

7 Months 

12 Months 

18 Months 

Study termination 

4/10 

5/10 

5/9 

7/10 

10/10 

MHV 

MHV 

MHV 

MHV 

MHV 

Clinical Pathology Groups 

6 Months 

12 Months 

18 Months 

1/9 

1/10 

1/10 

5/10 

5/10 

MVMc 

EDIM 

MHV 

Reovirus 3a 

M. arthritidisb 

AZT/5,000 U "-Interferon A/D 

Core Groups 

12 Months 

18 Months 

Study termination 

1/8 

1/8 

2/10 

Reovirus 3a 

Reovirus 3a 

M. arthritidisb 

Clinical Pathology Groups 

2 Months 

7 Months 

8 Months 

12 Months 

18 Months 

9/10 

8/10 

1/1 

5/10 

5/9 

MHV 

MHV 

MHV 

MHV 

MHV 

a The positive response for Reovirus 3 could not be confirmed by Western blot or colony epidemiology procedures; therefore, the titer is 

considered a false positive. b	 Further evaluation of the samples positive for M. arthritidis by immunoblot and Western blot procedures indicated that the positive titers may 

have been due to cross reaction with antibodies of nonpathogenic Mycoplasma or other agents. There were no clinical findings or 

histopathologic changes of M. arthritidis infection in animals with positive titers. Accordingly, M. arthritidis-positive titers were considered 

false positives. 

The sample positive for MVM was also evaluated for parvovirus antibodies by immunofluorescence assay; the result was negative. 
 

 

337 

APPENDIX R
 

IMPACT OF HELICOBACTER HEPATICUS
 

INFECTION IN B6C3F1 MICE

FROM 12 NTP 2-YEAR CARCINOGENESIS STUDIES
 

1 James R. Hailey , Joseph K. Haseman 1 1 1 , John R. Bucher , Ann E. Radovsky , 2 2 1 David E. Malarkey , Richard T. Miller , Abraham Nyska , and Robert R. Maronpot1
 

1

National Institute of Environmental Health Sciences
 

Research Triangle Park, North Carolina
 

2

Department of Microbiology, Pathology, and Parasitology
 

College of Veterinary Medicine
 

North Carolina State University
 

Raleigh, North Carolina
 

ABSTRACT ............................................................... 338
 

INTRODUCTION ............................................................ 338
 

MATERIALS AND METHODS .................................................... 339
 

RESULTS AND DISCUSSION ..................................................... 341
 

REFERENCES ............................................................. 348
 

TABLE 1 R1 Incidence of Helicobacter hepaticus-Associated Hepatitis in Control B6C3F Mice

from Nine NTP 2-Year Studies ........................................ 352
 

TABLE R2 Identification of Helicobacter hepaticus with PCR-RFLP-Based Assays
 

in Control B6C3F Mice from 32 NTP 2-Year Studies 1 

and Three NTP 13-Week Studies ...................................... 352
 

TABLE R3 Comparison of Neoplasm Incidences in Control B6C3F1
 Mice

from Helicobacter hepaticus-Affected and Unaffected NTP 2-Year Studies ........... 353
 

TABLE R4 Liver Neoplasm Incidences and Body Weights of Control B6C3F1
 Mice

in Relation to Study Start Dates of Helicobacter hepaticus-Affected 

and Unaffected NTP 2-Year Studies .................................... 354
 

TABLE R5 Association of Liver Neoplasm Incidence
 

and Severity of Helicobacter hepaticus-Associated Hepatitis 

in Control B6C3F Mice from Nine Affected NTP 2-Year Studies 1 ................. 355
 

TABLE R6	 H-ras Codon 61 AAA Mutations in Spontaneous Liver Neoplasms 

in Control B6C3F1 Mice from Helicobacter hepaticus-Affected

and Unaffected NTP 2-Year Studies .................................... 355
 

TABLE R7 Proliferating Cell Nuclear Antigen Labeling Indices in the Liver 

of Control B6C3F Mice 1 ............................................ 
 356 

TABLE R8 Summary of Target Sites of Carcinogenicity in B6C3F1
 Mice

from NTP 2-Year Studies with Helicobacter hepaticus-Associated Hepatitis .......... 357
 
338 AZT and AZT/"-Interferon A/D, NTP TR 469 

IMPACT OF HELICOBACTER HEPATICUS 

INFECTION IN B6C3F1 MICE

FROM 12 NTP 2-YEAR CARCINOGENESIS STUDIES 

ABSTRACT 

Male and female B6C3F1 mice from 12 NTP 2-year carcinogenesis studies were found to be infected with

Helicobacter hepaticus. Many of the male mice from nine of these studies (“affected” studies) had an 

associated hepatitis. The current evaluations were performed in an attempt to determine if the data from the 

H. hepaticus-affected NTP B6C3F1 mouse studies were compromised and unsuitable for cancer hazard

identification. The incidences of neoplasms of the liver (both hepatocellular neoplasms and 

hemangiosarcoma), but not of other organs in control male B6C3F1 mice, were found to be increased in

affected studies compared to control males from unaffected studies. The increased incidence of 

hepatocellular neoplasms was observed in those males exhibiting H. hepaticus-associated hepatitis. Other 

observations further differentiated control male mice from affected and unaffected studies. H-ras codon 61 

CAA-to-AAA mutations were less common in liver neoplasms in males from affected studies compared to 

historical and unaffected study controls. In addition, increases in cell proliferation rates and apoptosis were 

observed in the livers of male mice with H. hepaticus-associated hepatitis. These data support the 

hypothesis that the increased incidence of liver neoplasms is associated with H. hepaticus and that hepatitis 

may be important in the pathogenesis. Therefore, interpretation of carcinogenic effects in the liver of 

B6C3F mice may be confounded if there is H. hepaticus-associated hepatitis. 1 

INTRODUCTION 

Helicobacter-Induced Diseases 

Since the bacterium H. pylori was isolated from humans in 1983, numerous Helicobacter species have been 

identified in several laboratory and domestic animal species. Their pathogenicity varies, with some species 

inducing significant disease while others appear merely to colonize the gastrointestinal tract. H. pylori is 

known to cause chronic gastritis and peptic ulcers in humans (Marshall and Warren, 1984; Graham, 1989; 

Lee et al., 1993) and, more recently, has been linked to adenocarcinoma and mucosa-associated lymphoma 

of the stomach (Fox et al., 1989; Nomura et al., 1991; Parsonnet et al., 1991; Wotherspoon et al., 1993). 

Based on epidemiological and pathology findings, the International Agency for Research on Cancer (1994) 

has classified H. pylori as a group 1 carcinogen in humans. H. hepaticus is associated with an increase in 

liver neoplasm incidences in A/JCr mice (Ward et al., 1994a; Fox et al., 1996). 

H. hepaticus commonly colonizes the gastrointestinal tract of many strains of mice from many sources (Fox 

et al., 1994; Ward et al., 1994b; Shames et al., 1995). It has been shown to be pathogenic, with hepatitis 

highly prevalent in some strains of mice (A/JCr, BALB/cAnNCr, C3H/HeNCr, SJL/NCr, and SCID/NCr) 

(Ward et al., 1994b). Intestinal colonization does not necessarily result in subsequent hepatitis, and the 

conditions that lead to migration of the organism from the intestine to the liver have not been determined. 

H. hepaticus appears to reside primarily within the bile canaliculi. Male mice were reported to have a 

greater incidence and severity of hepatitis than female mice, and this finding occurred in NTP studies as 

well. The recently identified H. bilis, like H. hepaticus, colonizes the biliary tract, liver, and intestine of 

mice. While H. bilis has been identified in animals with chronic hepatitis, whether it caused the hepatitis is 

not known (Fox et al., 1995). 

The pathogenesis of H. hepaticus-induced disease has not been fully characterized. In susceptible strains of 

mice, H. hepaticus can cause acute, focal, nonsuppurative, necrotizing hepatitis, which progresses to 

chronic, active hepatitis characterized by minimal necrosis, hepatocytomegaly, oval cell hyperplasia, and 
AZT and AZT/"-Interferon A/D, NTP TR 469 339 

cholangitis. H. hepaticus has been found to possess high levels of urease (Fox et al., 1994). H. hepaticus 

is often isolated from the cecum and colon but is not necessarily isolated from the liver of A/JCr mice, even 

though these animals develop severe hepatitis. Culture supernatants from several strains of H. hepaticus 

and several other Helicobacter species were shown to cause cytopathic effects in a rodent hepatocyte cell 

line (Taylor et al., 1995). Ward et al. (1996) suggested that autoimmunity may play a role in the 

progressive hepatitis and carcinogenesis in livers infected with H. hepaticus. 

NTP Infectious Disease Surveillance 

In 1993, during the histological evaluation of an NTP 2-year study, pathologists identified a constellation of 

liver lesions (hepatitis) in control and treated male mice that was consistent with what would later be 

described in mice infected with H. hepaticus (Ward et al., 1993, 1994a; Fox et al., 1994). Subsequently, 

pathology results from all mouse studies begun since 1984 (67 two-year studies) were reviewed for 

diagnoses of the characteristic hepatitis; the lesions were identified in nine studies (NTP, 1998a,b,c,d, 

1999a,b). Silver stains revealed helical bacteria consistent with Helicobacter present in the liver of male 

mice in the nine studies. 

Every reasonable measure is taken to prevent the occurrence of infectious diseases during NTP 2-year 

carcinogenicity studies. When infections occasionally occur, care is taken to identify the causal agent and 

its source, measures are taken to ensure that animals in later studies will not be infected, and the potential 

impact on biological parameters (primarily neoplastic endpoints) important in interpretation of the study is 

determined. To date, animals (control and treated) from a few studies have had a mild pulmonary 

inflammatory response presumed to be caused by an infectious agent. In other studies, there have been 

utero-ovarian infections with Klebsiella sp. (Rao et al., 1987) and fungal infections of the nasal cavity. For 

scientifically valid reasons, interpretation of chemical-related effects was not considered significantly 

compromised in any of these studies. Unlike the previous infections, H. hepaticus involves the liver, the 

major metabolic organ, and has been associated with an increase in incidences of liver neoplasms in the 

A/JCr mouse (Ward et al., 1994a). Therefore, when the contemporary epizootic of H. hepaticus infection 

in the United States affected several NTP studies, use of the data for hazard identification was questioned. 

The first step was to determine the extent of the infection within NTP studies and then evaluate the impact 

the infection had on biological parameters important in interpretation of the carcinogenic potential of test 

chemicals. 

MATERIALS AND METHODS 

Histologic Examination 

Studies in which mice were potentially infected with H. hepaticus were identified by reviewing the summary 

pathology tables for characteristic diagnoses: oval and/or biliary epithelial hyperplasia, hepatocyte 

enlargement (often diagnosed as karyomegaly), chronic inflammation, and regenerative hyperplasia. All 

13-week and 2-year studies begun by the NTP since 1984 and for which complete pathology data were 

available (67 two-year studies) were examined. Eight contemporary studies in which the characteristic 

lesions were not identified from pathology tables were randomly selected for histologic reevaluation. Slides 

containing sections of hematoxylin- and eosin-stained livers from 20 to 25 control and 20 to 25 high-dose 

male mice from each of seven 2-year studies and one 13-week study (10 animals from each group) were 

reexamined microscopically for the presence of hepatitis potentially related to H. hepaticus infection. 

Hepatitis consistent with that observed with H. hepaticus infection was not observed in any of these studies. 

Liver sections from five or more animals from each of nine 2-year studies in which hepatitis was observed 

were prepared using the Warthin-Starry silver stain or Steiner’s modification to identify silver-positive 

helical bacteria. 
340 AZT and AZT/"-Interferon A/D, NTP TR 469 

PCR-RFLP Detection of Helicobacter DNA 

Assays based on polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) were 

conducted at the NIEHS (Malarkey et al., 1997) and the University of Missouri Research Animal 

Diagnostic and Investigative Laboratory (MU-RADIL) (Riley et al., 1996) on liver tissue from 

approximately 20 animals from each of 32 NTP 2-year studies (including the nine affected studies) and three 

NTP 13-week studies. The majority of these studies were selected because they were begun at 

approximately the same time (1988-1990) as the nine affected studies. Also, two earlier studies 

(1984-1985; mouse life-span and p-nitroaniline studies) and one later study (1993; methyleugenol) were 

selected. The mouse life-span study was designed to evaluate the incidences of spontaneous changes 

associated with age; therefore, there is no NTP Technical Report. Frozen tissue was available from 22 of 

these studies, while only formalin-fixed tissue was available for the remaining ten 2-year studies and the 

three 13-week studies. Most of the assays were conducted by MU-RADIL, which used Helicobacter genusspecific primers; MU-RADIL used restriction endonucleases on a subset of positives to determine if the 

species was H. hepaticus. DNA was isolated from frozen liver samples with a QIAamp Tissue Kit (Qiagen 

Inc., Chatsworth, CA) according to the manufacturer’s recommendations or routine phenol/chloroform 

extraction (Malarkey et al., 1997). DNA content and purity were determined spectrophotometrically by 

measuring the A260/A280 optical density ratio. To isolate DNA from paraffin-embedded samples, five 10-μm 

sections were washed twice with 1 mL xylene and twice with 500 μL ethanol. Tissues were then dried 

within a vacuum centrifuge prior to DNA isolation as described above. Routine measures were taken to 

avoid contamination at every step from tissue collection to PCR amplification, and concurrently run controls 

without DNA were consistently negative. 

Statistical Analyses 

Multiple regression procedures were used to compare control neoplasm rates in the nine affected studies 

with the 26 unaffected contemporary studies which had no histologic evidence of H. hepaticus-associated 

liver disease. While frozen liver tissue was unavailable from 13 of these 26 studies, none showed the 

hepatitis indicative of H. hepaticus and thus were assumed to be unaffected. Potential confounding factors 

such as body weight, date study was begun, route of administration, and animal supplier were included as 

covariables in the statistical analysis. 

Analysis for H-ras Codon 61 CAA-to-AAA Mutations 

For analyses of formalin-fixed tissue, three to five unstained serial sections (10 μm thick) were cut from 

paraffin blocks containing hepatocellular adenomas or carcinomas. Paraffin-embedded tissues were 

deparaffinized and rehydrated prior to being digested with proteinase k overnight at 55E C to isolate DNA. 

Frozen tissues were digested with 10 mg/mL pronase in 1% sodium dodecyl sulfate in TNE buffer (10 mM 

TRIS, 150 mM NaCl, and 2 mM EDTA; pH 7.5) overnight at 37E C; DNA was isolated by phenol 

chloroform extraction and precipitated with ethanol (Marmur, 1961; Sills et al., 1995). 

Nested primers were used for amplification of exon 2 of H-ras by PCR. The outer primers were 5'-CCA 

CTA AGC CTG TTG TGT TTT GCA G-3' (forward primer) and 5'-CTG TAC TGA TGG ATG TCC 

TCG AAG GA-3' (reverse primer). The inner primers (second round of amplification) were 5'-GAC ATC 

TTA GAC ACA GCA GTT-3' (forward primer) and 5'-GGT GTT GTT GAT GGC AAA TAC-3' (reverse 

primer). Although the normal sequence of codon 60 is GCT, the forward PCR primer is made with a T at 

the penultimate 3' base to create the restriction site for Mse1. 

A nonradioactive RFLP method was employed to identify CAA-to-AAA mutations in the H-ras gene at 

codon 61 in liver neoplasms (Lee and Drinkwater, 1995). This was based on Mse1 enzyme restriction 

cutting only the sequence 5'-TTAA-3'. Thus, Mse1 will detect CÿA conversion mutation at the first 

position of codon 61. 
AZT and AZT/"-Interferon A/D, NTP TR 469 341 

Analysis of PCNA and Apoptosis 

Detailed methods are included in a report by Nyska et al. (1997). Cell proliferation was assessed in 

nonneoplastic areas of the liver, kidney, and lung by determining a PCNA S-phase labeling index (the 

percentage of cells in S phase). The identification of apoptotic cells was based on morphologic criteria 

(Garewal et al., 1996; Goldsworthy et al., 1996) and confirmed immunohistochemically by the terminal 

deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) procedure (Gavrieli et al., 

1992). 

RESULTS AND DISCUSSION 

Identification of H. hepaticus Infection in NTP Studies 

Determining the extent of H. hepaticus infection involved a three-pronged approach of histologic evaluation, 

silver stains, and PCR-RFLP based assays; all were necessary because of the limitations identified for each. 

In NTP studies, and as reported in other studies (Ward et al., 1994b), there were no obvious clinical signs 

of infection, and the only significant histologic lesion (hepatitis) was observed in the liver, primarily in 

males. Therefore, summary pathology tables were reviewed to identify studies that may have been affected 

by H. hepaticus-associated hepatitis. Male mice from nine studies were identified (Table R1) as having the 

hepatitis. Eight of the nine studies were begun during a time span of about 6 months (July 1990 to 

January 1991), while the other study was begun much earlier (October 1988). The hepatitis was not 

observed in any 13-week studies. Use of histologic evaluation for identification of infected animals has 

limitations, however. It is somewhat insensitive, as H. hepaticus has been cultured and identified by PCRRFLP methods within livers of animals with no histological evidence of infection (Fox et al., 1999). This 

may be explained in part by the limited sampling (two liver sections) and the sometimes focal nature of 

H. hepaticus-associated hepatitis. Also, while in the more severely affected animals the hepatitis appears 

somewhat characteristic, component lesions of the hepatitis are not pathognomonic, and, when the hepatitis 

is subtle in 2-year old animals, it is more difficult to recognize or attribute to H. hepaticus. 

Within affected studies, the incidences of the hepatitis in male mice varied from 16% to 78% (Table R1). 

While generally mild to moderate, the hepatitis varied in severity from barely detectable in some animals to 

extensive liver involvement and regeneration in others. Only a few females were identified as having the 

characteristic hepatitis (Table R1). In general, the incidences and severities of H. hepaticus-associated 

hepatitis were similar between control and treated groups. This constellation of nonneoplastic liver lesions, 

while not pathognomonic, was certainly suggestive of an H. hepaticus infection, particularly when observed 

in control animals. Characteristic lesions included proliferation of oval and/or biliary epithelial cells, 

hepatocyte enlargement (diagnosed as karyomegaly), and chronic inflammation. In many instances, areas of 

regenerative hyperplasia were identified within diseased liver. 

Helicobacter spp. are not usually observed on routine histologic examination of hematoxylin and eosinstained sections of liver. The methods for confirmation of infection with Helicobacter include WarthinStarry silver stain or Steiner’s modification (Garvey et al., 1985) of this stain for direct microscopic 

observation of the organisms in tissue; however, this can be a relatively insensitive technique when few 

organisms are present. In most instances, histologic differentiation between Helicobacter species is not 

possible. Speciation can usually be accomplished with electron microscopy, but this technique is both time 

consuming and labor intensive. Microbiologic culture of feces, cecal smears, and fresh or frozen liver is 

also possible. Currently, assays involving amplification of the DNA of the organism using PCR are the 

most rapid and perhaps the most sensitive methods of detection, and the use of restriction endonucleases has 

allowed a determination of the species present. PCR-based methods also can be used on feces, cecal 

contents, or liver homogenates and are most sensitive when using fresh or frozen tissue (Riley et al., 1996; 

Malarkey et al., 1997). 
342 AZT and AZT/"-Interferon A/D, NTP TR 469 

Using Warthin-Starry silver stains or Steiner’s modification on the livers of five or more animals per study, 

helical bacteria (Helicobacter) were identified in animals from the nine affected studies. In some animals, 

helical bacteria were numerous, suggesting a heavy bacterial burden in these infected animals. However, 

even in these animals with abundant organisms, few to none were observed in proliferative hepatic lesions 

such as foci and neoplasms. Helical bacteria were not identified in approximately 25% of males with 

moderate hepatitis and were rarely identified in males without hepatitis or in females. The absence of 

identification of helical organisms by silver stains does not preclude infection, nor does the presence of 

organisms confirm H. hepaticus. Based upon current knowledge, however, the characteristic liver lesions 

in B6C3F mice, coupled with the presence of silver-positive helical organisms, are highly suggestive of 1 

H. hepaticus infection. 

As the NTP evaluation evolved, PCR-based assays were developed that appeared more sensitive than 

histologic evaluation and silver stains for identification and speciation of Helicobacter. Therefore, 

PCR-RFLP-based assays were used to confirm the presence of pathogenic Helicobacter (primarily 

H. hepaticus) within the nine affected studies and to determine whether there was H. hepaticus infection in 

other NTP studies. Unfortunately, none of the PCR-based assays had been specifically developed for, or 

proven reliable for use with, formalin-fixed tissue. Frozen tissue was available from a limited number of 

animals from a limited number of NTP studies, including only three of the nine affected studies. 

Furthermore, available frozen liver was almost always limited to tissue from a neoplasm, and, based upon 

results obtained with silver stains, organisms are generally not readily observed within proliferative hepatic 

lesions, even when organisms are abundant in adjacent liver tissue. Because the availability of frozen tissue 

was limited, a PCR-RFLP-based assay was developed and evaluated (Malarkey et al., 1997) for use with 

frozen or formalin-fixed tissue. 

The NIEHS and MU-RADIL laboratories conducted PCR-RFLP-based assays on 32 NTP 2-year studies and 

three NTP 13-week studies (data not shown); frozen tissues from 22 of the 2-year studies were available. 

All three bioassays in which hepatitis was identified and for which frozen tissue was available were positive 

for H. hepaticus by the PCR-RFLP-based assays (Table R2). At a third laboratory, H. hepaticus was also 

cultured from the liver tissue of animals in one of these studies (Fox et al., 1999). Formalin-fixed tissues 

from two of the three studies were evaluated and were also positive; these tissues had been fixed in formalin 

for less than 48 hours. In the other six affected studies, for which only formalin-fixed tissue was available, 

H. hepaticus was identified in only 1 of 120 animals (Table R2). This decreased sensitivity was considered 

to be related to the prolonged formalin fixation (Malarkey et al., 1997) rather than proof of an absence of 

H. hepaticus. The presence or absence of H. hepaticus apparently cannot be confirmed with current PCRRFLP-based assays in liver that has been fixed in formalin for long periods (weeks or months). In the three 

13-week studies with formalin-fixed tissue, only 1 of 30 animals was positive for H. hepaticus. 

Within the three affected, PCR-RFLP-positive 2-year studies, H. hepaticus was often identified by PCR in 

frozen livers of mice that had no overt hepatitis. In fact, based upon the combined data from two studies 

(including PCR results from three laboratories), of 57 animals without characteristic liver lesions, 13 of 

24 male mice (54%) and 17 of 33 female mice (52%) were positive for H. hepaticus. Furthermore, 

H. hepaticus was identified by PCR in frozen liver of several animals from three “unaffected” studies in 

which hepatitis typical of that associated with H. hepaticus was not observed (Table R2). Apparent 

variability occurs between various strains of mice and between individual mice from affected studies in 

developing hepatitis in response to H. hepaticus infection. One would assume that, within affected studies, 

most or all animals have been exposed to the organism, and even animals resistant to developing hepatitis 

may have organisms within the liver. This assumption is supported by the fact that animals without hepatitis 

are often positive with PCR-RFLP-based assays. Therefore, although alternative explanations are possible, 

the three PCR-RFLP-positive studies in which liver lesions are absent are assumed to be true positives. In 

fact, helical organisms were identified with a silver stain in one animal from one of these studies (Malarkey 
AZT and AZT/"-Interferon A/D, NTP TR 469 343 

et al., 1997). Therefore, in addition to assessing the affect of H. hepaticus in the nine affected 2-year 

studies, the significance of a positive PCR-RFLP assay for H. hepaticus in the absence of liver lesions is 

also an important question. 

Inconsistent Results with PCR-Based Methods 

As with any technique, the PCR-RFLP-based assays have limitations even when used to assay fresh and 

frozen tissue. One assessment of the variability in results of PCR and serologic analyses for Helicobacter 

among three commercial laboratories revealed significant inconsistencies (Dew et al., 1997). Others 

(J.M. Ward and J. Thigpen, personal communications) have obtained similarly inconsistent results when 

sending replicate samples to different laboratories. Though the number of samples evaluated by both the 

NIEHS and MU-RADIL laboratories was limited, there was good, but not complete, correlation of 

PCR-RFLP results. Also, within the affected studies, the PCR assays were not positive in some animals 

with liver disease. This result may be explained, in part, by the fact that the only frozen tissues available 

were neoplasms; as described above, neoplasms are expected to have fewer organisms. 

Analysis of H. hepaticus-Affected and Unaffected Studies 

for Incidence of Common Neoplasms 

To determine whether the incidences of various neoplasms were different between control groups from 

affected and unaffected studies, the nine affected studies were compared to 26 unaffected studies begun at 

relatively similar times (Table R3). There were no statistically significant differences in body weight or 

survival among the affected and unaffected studies. The neoplasms evaluated represent those that occurred 

at high enough incidences in various organs for statistically significant differences to be detected. Using 

multiple regression procedures, male mice in the nine affected studies were demonstrated to have a 

significantly (P<0.05) increased incidence of only two neoplasm types, both of which were in the liver 

(hepatocellular neoplasms and hemangiosarcoma), when compared to the unaffected studies. Because of 

these differences, there was also a corresponding significant difference in the overall incidence of malignant 

neoplasms (all sites) as well as in the overall proportion of neoplasm-bearing animals. No other tissue site 

showed a significant difference in the incidence of neoplasms. For female mice, the slightly increased 

incidence of hepatocellular neoplasms observed in the affected studies was not statistically significant. 

This seemingly simple analysis is complicated by several potential confounding variables. There have been 

coordinate, time-related increases in body weight and in the incidence of liver neoplasms in mice in NTP 

studies (Haseman, 1992). Table R4 presents the liver neoplasm incidences in relation to the dates the 

studies began and clearly shows the increases in liver neoplasm incidences and body weights (Seilkop, 

1995). In assessing differences in neoplasm incidences between H. hepaticus-affected and unaffected 

studies, the most relevant comparison would be between studies begun at approximately the same time. The 

starts of 20 of the 26 unaffected studies were clustered near the early part of the time frame (April 1988 to 

June 1990), while the starts of the affected studies were clustered toward the later end, with eight of the 

nine studies begun between July 1990 and January 1991; incidences of liver neoplasms in these later studies 

are expected to be higher based on trends in body weight alone. While the slightly increased incidences of 

liver neoplasms observed in female control mice in the nine affected studies is likely due to clustering in 

time, clearly, this alone cannot account for the increased liver neoplasm incidences observed in control male 

mice in the affected studies (Table R3). 

Ideally, unaffected studies used in the above comparison should not only be free of histologic evidence of 

infection with H. hepaticus but should be confirmed as negative by PCR assays. Thirteen of these 

26 studies could not be confirmed as negative by PCR because frozen tissue was not available; however, 

H. hepaticus-associated hepatitis was not present in any of the 26 studies. Because these and other data 

reported to date suggest that hepatitis is associated with neoplasm development in the liver, it seems 

reasonable to include those 13 studies, unconfirmed by PCR, in this analysis. The majority of the 

13 studies confirmed as negative by PCR were begun much earlier than the clearly affected studies, and, 
344 AZT and AZT/"-Interferon A/D, NTP TR 469 

therefore, comparing them alone to the nine affected studies is not reasonable. Although not presented 

here, a number of comparisons were made with various groupings of studies based on the degree of 

confidence in their infection status. Although the outcomes of the various comparisons varied somewhat, 

incidences of hepatocellular neoplasms and hemangiosarcomas of the liver were consistently increased in 

control male mice from affected studies compared to control males from unaffected studies. Significantly 

increased liver neoplasm incidences generally were not observed in females. Importantly, the following 

data corroborate the findings and association with H. hepaticus identified in these analyses. 

Analysis of Hepatitis-Positive and Hepatitis-Negative Mice 

for Liver Neoplasm Incidence 

Several infectious agents known to be associated with increased incidences of neoplasms cause chronic 

inflammation in the target tissue or organ. It is commonly hypothesized that this inflammatory process may 

cause or contribute to the development of neoplasms. One approach to address this was to stratify the mice 

from the affected studies according to the severity of hepatitis and examine liver neoplasm incidences in 

relation to these groupings. Thus, animals within the nine affected studies were placed into three groups: 

1) animals with mild to moderate hepatitis considered related to H. hepaticus infection (+), 2) animals with 

minimal to mild hepatitis that may have been associated with H. hepaticus (±), and 3) animals with no 

hepatitis that was considered to be associated with H. hepaticus (S). Within these groupings, the incidence 

of liver neoplasms was significantly increased (P<0.05) in males with mild to moderate H. hepaticusassociated hepatitis (+) when compared to animals without such hepatitis (Table R5). The neoplasm 

incidence in animals with minimal lesions (±) was also increased. The liver neoplasm incidence in males 

without hepatitis (58%) was similar to the incidence (54.8%) in males from the 26 unaffected studies 

(Table R3). This analysis clearly suggests an association of H. hepaticus-associated hepatitis with increased 

liver neoplasm incidences. Females showed a similar trend, albeit not significant; however, these 

comparisons are weak because of the low numbers of females with hepatitis. 

Analysis of H-ras Oncogene Mutations in Liver Neoplasms in Mice 

from Affected and Unaffected Studies 

Liver neoplasms commonly occur in control B6C3F mice in 2-year studies. In the historical database of 1 

333 male and female mice with liver neoplasms, 106 (32%) had H-ras codon 61 CAA-to-AAA mutations 

(Maronpot et al., 1995). This historical control database is composed primarily of male data; however, 

adequate numbers of females have been assayed, and there was no significant difference in the incidences of 

CAA-to-AAA mutations between males and females. 

In an attempt to examine further whether H. hepaticus infection had an effect on the development of 

hepatocellular neoplasms, neoplasms from control male mice from selected affected (NTP, 1998a,b, 1999a) 

and unaffected (NTP, 1993, 1999c) studies were evaluated for H-ras codon 61 CAA-to-AAA mutations 

(Table R6). Only 6% (2/33) of the hepatocellular neoplasms from control males with hepatitis from three 

affected studies had this mutation. This percentage is significantly (P<0.01) less than the 32% (11/34) 

observed in males from the two unaffected studies and less than the 32% (106/333) that occurred in 

historical control animals. In addition, neoplasms from males without hepatitis from the affected, PCRpositive triethanolamine study (NTP, 1999a) and the unaffected, PCR-positive methyleugenol study (NTP, 

1999d) were evaluated; the incidences of mutations in those groups were 3/14 (21%) and 2/17 (12%), 

respectively. 

Neoplasms from control female mice (none had hepatitis) from affected and unaffected studies were 

evaluated for the CAA-to-AAA mutation (Table R6). The mutation rate was low in both the affected studies 

(1/25; 4%) and the unaffected study (1/11; 9%) when compared to the 32% observed in the historical 

control groups. 
AZT and AZT/"-Interferon A/D, NTP TR 469 345 

The finding of a different H-ras mutation profile in neoplasms of male mice from affected studies tends to 

support the association of increased neoplasm incidences with H. hepaticus, although there is no mechanistic 

understanding behind this observation. In a study of H. hepaticus-infected A/JCr mice, ras mutations were 

not detected in the 25 hepatocellular neoplasms analyzed using a PCR/single-strand conformation 

polymorphism assay (Sipowicz et al., 1997). Because of the low spontaneous rate of liver neoplasms in the 

A/JCr mouse, there are few or no conclusive data on ras mutations in uninfected animals, however. Point 

mutations at codons 12, 13, and 61 of the Ki-, Ha- and N-ras genes were not identified in 45 early gastric 

carcinomas in humans, whether or not H. pylori was present (Craanen et al., 1995). If the increased 

incidence of hepatocellular neoplasms is associated with hepatitis, as many suspect, then one would expect 

the neoplasms from animals without hepatitis to have a similar mutational profile as that of the historical 

controls. The data do not provide a clear answer, because the hepatitis-free males from the affected 

triethanolamine study (NTP, 1999a) and the males from the methyleugenol study (NTP, 1999d), which were 

positive by PCR but lacked hepatitis, had mutation frequencies between those of the unaffected controls and 

the hepatitis-positive mice. Furthermore, mutations in neoplasms from females, none of which had 

hepatitis, from two affected and one unaffected study were very low compared to the historical controls. 

These findings were unexpected, and their significance is not understood. 

H. hepaticus-Associated Alterations in Cell Kinetics 

Studies evaluating cell kinetics were completed to explore further the link between hepatitis and the 

increased incidence of liver neoplasms (Table R7; Nyska et al., 1997). One of the major objectives was to 

determine whether there were differences between PCNA labeling indices in the livers of animals with 

hepatitis from three affected studies, triethanolamine, cobalt sulfate heptahydrate, and chloroprene (NTP, 

1998a,b, 1999a), compared to animals without hepatitis, whether from the same three affected studies or 9 from an unaffected study, 1-trans-delta -tetrahydrocannabinol (NTP, 1996). Male mice with hepatitis from 

the three affected studies had a significantly increased (P<0.001) labeling index, with a 24-fold increase 

over males from the unaffected study and a sixfold increase over males without hepatitis from the same 

three affected studies (Table R7). The labeling index increase in these mice was substantial and was 

considered biologically significant. Male mice without hepatitis from the three affected studies had a 

significantly greater labeling index (increased fourfold) than male mice from the unaffected study 

(Table R7). The significance of this finding is uncertain, as differences of a similar magnitude were 

observed in other comparisons. For example, the labeling index of females from the unaffected 1-trans­ 9 delta -tetrahydrocannabinol study (Table R7; NTP, 1996) was increased fivefold over females from the

PCR-positive, hepatitis-negative scopolamine hydrobromide trihydrate study (NTP, 1997). Such differences 

may be within the limits of normal variability for 2-year-old animals. 

A second objective of the cell proliferation studies of the liver was to determine if labeling indices were 

increased in animals from the PCR-positive, hepatitis-negative methyleugenol (NTP, 1999d), scopolamine 

hydrobromide trihydrate (NTP, 1997), and mouse life-span studies compared to an unaffected PCR-negative 9 and hepatitis-negative 1-trans-delta -tetrahydrocannabinol study (NTP, 1996). The scopolamine 

hydrobromide trihydrate study was evaluated and included in the study by Nyska et al. (1997), while the 

methyleugenol and mouse life-span studies were completed later and are included in Table R7. The labeling 

indices of males from two of these three studies were almost identical to those of males from the unaffected 

study. However, the labeling index of males from the mouse life-span study is increased approximately 

fivefold over that of males from the unaffected study as well as fivefold over the labeling indices of males 

from the two like studies of scopolamine hydrobromide trihydrate and methyleugenol. This finding suggests 

that the increase observed in the mouse life-span study is not attributable to the presence of H. hepaticus, as 

two other studies also positive for H. hepaticus did not show a similar increase. 

The cell proliferation data for the liver from NTP studies are consistent with data from a study by Fox et al. 

(1996) in which cell proliferation indices were evaluated at 8, 10, and 13 months in the A/JCr mouse, 

which is generally believed to be more susceptible to H. hepaticus-associated hepatitis than the B6C3F1 
346 AZT and AZT/"-Interferon A/D, NTP TR 469 

mouse. In the study by Fox et al. (1996), cell proliferation rates were significantly increased at all time 

points in males. Some increases were observed in females in that study but did not reach statistical 

significance. An increased incidence of hepatocellular neoplasms was observed only in the males. Though 

liver lesions were observed in females in that study, they were less severe than those in males. 

In addition to the liver, cell proliferation indices (PCNA) were evaluated in the kidneys and lungs of male 

and female mice in affected studies versus those in unaffected studies (Nyska et al., 1997). No apparent 

effect of H. hepaticus infection or the presence of hepatitis on PCNA indices was observed for the kidneys 

or lungs. 

Apoptosis (programmed cell death) is another important parameter in evaluations of cell kinetics. The 

apoptotic index in the liver of male mice with hepatitis from an affected study, cobalt sulfate heptahydrate 

(NTP, 1998b), was significantly (P<0.01) greater than that observed in males from the unaffected 1-trans­ 9 delta -tetrahydrocannabinol study and the PCR-positive, hepatitis-negative scopolamine hydrobromide

trihydrate study (Nyska et al., 1997). For females, there were no significant differences among the three 

studies. 

Two 13-week studies which were begun during the same time as the nine affected studies were randomly 

selected for evaluation of PCNA indices. H. hepaticus was not identified in either of the studies by 

PCR-RFLP; however, as with all NTP 13-week studies, only tissue fixed in formalin for an unspecified 

period was available. Because of this, no true negative control group was available; therefore, the labeling 

index of these 19- to 20-week-old animals was compared to values cited in the literature (Eldridge and 

Goldsworthy, 1996) for 20-week-old B6C3F mice. The labeling index in the NTP studies clearly was not 1 

increased (data not shown). 

The Impact of H. hepaticus on the Interpretation of 2-Year Carcinogenesis Studies 

Increases in the incidences of neoplasms are associated with a number of infectious agents. The chronic 

inflammation caused by these agents has been hypothesized to be important in the pathogenesis of the 

increased neoplasm incidences (e.g., gastric cancer associated with H. pylori). The increased incidences of 

liver neoplasms in male mice from the nine affected NTP studies were observed in the animals with 

H. hepaticus-associated hepatitis. Neoplasms from males with hepatitis tended to have an H-ras mutation 

profile different from that of animals from unaffected studies. Further, cell replication rates at 2 years were 

significantly higher in males with hepatitis compared to those in males without hepatitis. The data suggest 

that H. hepaticus-associated hepatitis is associated with the increased incidences of liver neoplasms in the 

male B6C3F1 mouse. Therefore, the most important consideration in evaluating the impact of H. hepaticus 

infection on the interpretation of study results appears to be the presence or absence of significant hepatitis. 

For any carcinogenicity study, data within and specific to the individual study provide the greatest basis for 

an accurate interpretation. However, it is prudent to consider and evaluate all data or information which 

may affect the interpretation. Based upon the data presented in this and other reports, general guidelines 

emerge that may be useful in interpreting potential chemical-associated carcinogenic effects in H. hepaticusinfected B6C3F mice. In a study with sufficient evidence of H. hepaticus-associated hepatitis (>10% of 1 

the animals having the characteristic hepatitis may be a reasonable guideline), interpretation of increased 

incidences of liver neoplasms (hepatocellular neoplasms and hemangiosarcoma) of male mice is considered 

to be potentially confounded. 

Altered chemical uptake and metabolism, due to the intestinal load of H. hepaticus and to H. hepaticusassociated liver disease, respectively, are possible reasons for considering that the male mouse response to 

chemical administration at sites other than the liver should also be considered confounded. Data do not 

currently exist that definitively answer this question. In this group of nine studies, however, there is no 

evidence to suggest that affected mice responded to chemical treatment in organs other than the liver in a 
AZT and AZT/"-Interferon A/D, NTP TR 469 347 

manner different from mice in nonaffected studies. Within each study, there was excellent concordance in 

chemical-associated neoplasms between the male mice and the females, which had little or no hepatitis 

(Table R8). Furthermore, analyses indicate that H. hepaticus is not associated with neoplastic responses 

outside the liver; incidences of neoplasms at sites other than the liver were not different between control 

groups from affected and unaffected studies (Table R3). Cell replication rates in two major organs (lung 

and kidney) also were not increased in control groups from affected studies compared to those from 

unaffected studies. 

One of the more difficult issues to address is whether interpretation of a treatment-related increase in liver 

neoplasm incidences in the female mouse is confounded when H. hepaticus-associated hepatitis is present 

within the male mice in the study. Most evidence to date links hepatitis with the increased liver neoplasm 

incidences observed in males, and female B6C3F mice in affected studies do not have significant hepatitis 1 

at 2 years. The lack of hepatitis in females, however, is based on an analysis in which only late time points 

were evaluated histologically. Therefore, it is conceivable that hepatitis along with increased cell 

proliferation could have occurred earlier and resolved by 18 months to 2 years. Data collected to date, 

however, suggest that H. hepaticus-associated hepatitis is a late-developing and persistent disease in the 

B6C3F1 mouse. H. hepaticus-associated hepatitis has never been observed in any NTP 13-week studies, 

including five begun during the same 6-month time span as eight of the nine affected 2-year studies. Also, 

within affected 2-year studies, more males (51%) that were 18 to 24 months of age had hepatitis than those 

(34%) that were 12 to 18 months of age. This is consistent with a report by Ward et al. (1994b) that 

H. hepaticus-associated liver lesions are not observed at early time points in the B6C3F1 mouse. 

Nonetheless, within affected studies, female control mice did have a slightly elevated incidence of liver 

neoplasms when compared to control mice from unaffected studies, and the data derived from the H-ras 

mutation frequency analysis were inconclusive. The possibility that H. hepaticus-infected female mice from 

affected studies may respond differently to a liver carcinogen than mice from unaffected studies cannot be 

eliminated at this time. However, because within an affected study hepatitis is observed only rarely in 

females, until definitive data suggest otherwise, it is concluded that the interpretation of an apparent 

chemical-induced neoplastic effect in the liver of female mice is not confounded. To censor the few females 

with H. hepaticus-associated hepatitis from any statistical analyses of hepatocellular neoplasms would be 

prudent. Studies in the ostensibly more sensitive A/JCr mouse (Fox et al., 1996) also showed significant 

increases in neoplasm incidences and cell proliferation rates in the liver of H. hepaticus-infected males, but 

not females. 

Another concern is how to interpret possible chemical-related effects in a study in which the status of 

H. hepaticus infection cannot be determined by PCR-RFLP because only tissues fixed in formalin for more 

than 48 hours are available. While histologic evaluation is inadequate to identify infection, it appears 

adequate for identifying hepatitis severe enough to alter the outcome of the study. Therefore, in the absence 

of significant histologic evidence of H. hepaticus-associated hepatitis, the outcome of a 2-year study should 

not be considered potentially compromised. 

The causality between H. hepaticus infection and neoplasia has not been proven in the B6C3F1 mouse in

these studies, nor has the mechanism of this association been determined; further studies are needed. 

However, sufficient information exists to make reasonable scientific judgments relative to the interpretation 

of data from the nine 2-year carcinogenicity studies in the B6C3F1 mouse. Refinements to the above 

interpretive positions may occur if warranted by future information. 
348 AZT and AZT/"-Interferon A/D, NTP TR 469 

REFERENCES 

Craanen, M.E., Blok, P., Top, B., Boerrigter, L., Dekker, W., Offerhaus, G.J.A., Tytgat, G.N.J., and
 

Rodenhuis, S. (1995). Absence of ras gene mutations in early gastric carcinomas. Gut 37, 758-762.
 

Dew, J.A., Clifton, L.G., Sanders, B.L., and Reynolds, R.P. (1997). Comparison of results of
 

Helicobacter tests performed by commercial laboratories. Contemp. Top. (AALAS) 36, 60. (Abstr.)
 

Eldridge, S.R., and Goldsworthy, S.M. (1996). Cell proliferation rates in common cancer target tissues of
 

B6C3F1 mice and F344 rats: Effects of age, gender, and choice of marker. Fundam. Appl. Toxicol. 32,
 

159-167.
 

Fox, J.G., Correa, P., Taylor, N.S., Zavala, D., Fontham, E., Janney, F., Rodriquez, E., Hunter, F., and
 

Diavolitsis, S. (1989). Campylobacter pylori-associated gastritis and immune response in a population at
 

increased risk of gastric carcinoma. Am. J. Gastroenterol. 84, 775-781.
 

Fox, J.G., Dewhirst, F.E., Tully, J.G., Paster, B.J., Yan, L., Taylor, N.S., Collins, M.J., Jr.,
 

Gorelick, P.L., and Ward, J.M. (1994). Helicobacter hepaticus sp. nov., a microaerophilic bacterium
 

isolated from livers and intestinal mucosal scrapings from mice. J. Clin. Microbiol. 32, 1238-1245.
 

Fox, J.G., Yan, L.L., Dewhirst, F.E., Paster, B.J., Shames, B., Murphy, J.C., Hayward, A.,
 

Belcher, J.C., and Mendes, E.N. (1995). Helicobacter bilis sp. nov., a novel Helicobacter species isolated
 

from bile, livers, and intestines of aged, inbred mice. J. Clin. Microbiol. 33, 445-454.
 

Fox, J.G., Li, X., Yan, L., Cahill, R.J., Hurley, R., Lewis, R., and Murphy, J.C. (1996). Chronic
 

proliferative hepatitis in A/JCr mice associated with persistent Helicobacter hepaticus infection: A model of
 

Helicobacter-induced carcinogenesis. Infect. Immun. 64, 1548-1558.
 

Fox, J.G., MacGregor, J., Shen, Z., Li, X., Lewis, R., and Dangler, C.A. (1999). Role of Helicobacter
 

hepaticus in confounding results of a triethanolamine carcinogenesis study in mice. J. Clin. Microbiol.
 

(in press)
 

Garewal, H., Bernstein, H., Bernstein, C., Sampliner, R., and Payne, C. (1996). Reduced bile acidinduced apoptosis in “normal” colorectal mucosa: A potential biological marker for cancer risk. Cancer
 

Res. 56, 1480-1483.
 

Garvey, W., Fathi, A., and Bigelow, F. (1985). Modified Steiner for the demonstration of spirochetes. 

J. Histotechnol. 8, 15-17. 

Gavrieli, Y., Sherman, Y., and Ben-Sasson, S.A. (1992). Identification of programmed cell death in situ 

via specific labeling of nuclear DNA fragmentation. J. Cell Biol. 119, 493-501. 

Goldsworthy, T.L., Fransson-Steen, R., and Maronpot, R.R. (1996). Importance of and approaches to 

quantification of hepatocyte apoptosis. Toxicol. Pathol. 24, 24-35. 

Graham, D.Y. (1989). Campylobacter pylori and peptic ulcer disease. Gastroenterology 96, 615-625. 

Haseman, J.K. (1992). Value of historical controls in the interpretation of rodent tumor data. Drug Inf. J. 

26, 191-200. 
AZT and AZT/"-Interferon A/D, NTP TR 469 349 

International Agency for Research on Cancer (IARC) (1994). IARC Monographs on the Evaluation of 

Carcinogenic Risks to Humans: Schistosomes, Liver Flukes and Helicobacter pylori, Vol. 61. IARC, 

Lyon, France. 

Lee, A., Fox, J., and Hazell, S. (1993). Pathogenicity of Helicobacter pylori: A perspective. Infect. 

Immun. 61, 1601-1610. 

Lee, G.-H., and Drinkwater, N.R. (1995). Hepatocarcinogenesis in BXH recombinant inbred strains of 

mice: Analysis of diverse phenotypic effects of the hepatocarcinogen sensitivity loci. Mol. Carcinog. 14, 

190-197. 

Malarkey, D.E., Ton, T.-V., Hailey, J.R., and Devereaux, T.R. (1997). A PCR-RFLP method for the 

detection of Helicobacter hepaticus in frozen or fixed liver from B6C3F mice. Toxicol. Pathol. 25, 1 

606-612. 

Marmur, J. (1961). A procedure for the isolation of deoxyribonucleic acid from micro-organisms. J. Mol. 

Biol. 3, 208-218. 

Maronpot, R.R., Fox, T., Malarkey, D.E., and Goldsworthy, T.L. (1995). Mutations in the ras protooncogene: Clues to etiology and molecular pathogenesis of mouse liver tumors. Toxicology 101, 125-156. 

Marshall, B.J., and Warren, J.R. (1984). Unidentified curved bacilli in the stomach of patients with 

gastritis and peptic ulceration. Lancet 1, 1311-1314. 

National Toxicology Program (NTP) (1993). Toxicology and Carcinogenesis Studies of Oxazepam (CAS 

No. 604-75-1) in Swiss Webster and B6C3F1 Mice (Feed Studies). Technical Report Series No. 443. NIH

Publication No. 93-3359. U.S. Department of Health and Human Services, Public Health Service, National 

Institutes of Health, Research Triangle Park, NC. 

9 National Toxicology Program (NTP) (1996). Toxicology and Carcinogenesis Studies of 1-Trans-delta ­

tetrahydrocannabinol (CAS No. 1972-08-3) in F344/N Rats and B6C3F Mice (Gavage Studies). Technical 1 

Report Series No. 446. NIH Publication No. 97-3362. U.S. Department of Health and Human Services, 

Public Health Service, National Institutes of Health, Research Triangle Park, NC. 

National Toxicology Program (NTP) (1997). Toxicology and Carcinogenesis Studies of Scopolamine 

Hydrobromide Trihydrate (CAS No. 6533-68-2) in F344/N Rats and B6C3F Mice (Gavage Studies). 1 

Technical Report Series No. 445. NIH Publication No. 97-3361. U.S. Department of Health and Human 

Services, Public Health Service, National Institutes of Health, Research Triangle Park, NC. 

National Toxicology Program (NTP) (1998a). Toxicology and Carcinogenesis Studies of Cobalt Sulfate 

Heptahydrate (CAS No. 10026-24-1) in F344/N Rats and B6C3F Mice (Inhalation Studies). Technical 1 

Report Series No. 471. NIH Publication No. 98-3961. U.S. Department of Health and Human Services, 

Public Health Service, National Institutes of Health, Research Triangle Park, NC. 

National Toxicology Program (NTP) (1998b). Toxicology and Carcinogenesis Studies of Chloroprene 

(CAS No. 126-99-8) in F344/N Rats and B6C3F Mice (Inhalation Studies). Technical Report Series 1 

No. 467. NIH Publication No. 98-3957. U.S. Department of Health and Human Services, Public Health 

Service, National Institutes of Health, Research Triangle Park, NC. 

National Toxicology Program (NTP) (1998c). Toxicology and Carcinogenesis Studies of Technical Grade 

Sodium Xylenesulfonate (CAS No. 1300-72-7) in F344/N Rats and B6C3F Mice (Dermal Studies). 1 
350 AZT and AZT/"-Interferon A/D, NTP TR 469 

Technical Report Series No. 464. NIH Publication No. 98-3380. U.S. Department of Health and Human 

Services, Public Health Service, National Institutes of Health, Research Triangle Park, NC. 

National Toxicology Program (NTP) (1998d). Toxicology and Carcinogenesis Studies of Theophylline 

(CAS No. 58-55-9) in F344/N Rats and B6C3F Mice (Feed and Gavage Studies). Technical Report Series 1 

No. 473. NIH Publication No. 98-3963. U.S. Department of Health and Human Services, Public Health 

Service, National Institutes of Health, Research Triangle Park, NC. 

National Toxicology Program (NTP) (1999a). Toxicology and Carcinogenesis Studies of Triethanolamine 

(CAS No. 102-71-6) in F344/N Rats and B6C3F Mice (Dermal Studies). Technical Report Series 1 

No. 449. NIH Publication No. 99-3365. U.S. Department of Health and Human Services, Public Health 

Service, National Institutes of Health, Research Triangle Park, NC. (in press) 

National Toxicology Program (NTP) (1999b). Toxicology and Carcinogenesis Studies of AZT (CAS 

No. 30516-87-1) and AZT/"-Interferon A/D in B6C3F Mice (Gavage Studies). Technical Report Series 1 

No. 469. NIH Publication No. 99-3959. U.S. Department of Health and Human Services, Public Health 

Service, National Institutes of Health, Research Triangle Park, NC. 

National Toxicology Program (NTP) (1999c). Toxicology and Carcinogenesis Studies of Diethanolamine 

(CAS No. 111-42-2) in F344/N Rats and B6C3F Mice (Dermal Studies). Technical Report Series 1 

No. 478. NIH Publication No. 99-3968. U.S. Department of Health and Human Services, Public Health 

Service, National Institutes of Health, Research Triangle Park, NC. (in press) 

National Toxicology Program (NTP) (1999d). Toxicology and Carcinogenesis Studies of Methyleugenol 

(CAS No. 93-15-2) in F344/N Rats and B6C3F Mice (Gavage Studies). Technical Report Series No. 491. 1 

NIH Publication No. 99-3950. U.S. Department of Health and Human Services, Public Health Service, 

National Institutes of Health, Research Triangle Park, NC. (in press) 

Nomura, A., Stemmermann, G.N., Chyou, P., Kato, I., Perez-Perez, G.I., and Blaser, M.J. (1991). 

Helicobacter pylori infection and gastric carcinoma among Japanese Americans in Hawaii. N. Engl. J. 

Med. 325, 1132-1136. 

Nyska, A., Maronpot, R.R., Eldridge, S.R., Haseman, J.K., and Hailey, J.R. (1997). Alteration in cell 

kinetics in control B6C3F mice infected with Helicobacter hepaticus. Toxicol. Pathol. 25, 591-596. 1 

Parsonnet, J., Friedman, G.D., Vandersteen, D.P., Chang, Y., Vogelman, J.H., Orentreich, N., and 

Sibley, R.K. (1991). Helicobacter pylori infection and the risk of gastric carcinoma. N. Engl. J. Med. 

325, 1127-1131. 

Rao, G.N., Hickman, R.L., Seilkop, S.K., and Boorman, G.A. (1987). Utero-ovarian infection in aged 

B6C3F1 mice. Lab. Animal Sci. 37, 153-158. 

Riley, L.K., Franklin, C.L., Hook, R.R., Jr., and Besch-Williford, C. (1996). Identification of murine 

Helicobacters by PCR and restriction enzyme analyses. J. Clin. Microbiol. 34, 942-946. 

Seilkop, S.K. (1995). The effect of body weight on tumor incidence and carcinogenicity testing in B6C3F1 

mice and F344 rats. Fundam. Appl. Toxicol. 24, 247-259. 

Shames, B., Fox, J.G., Dewhirst, F., Yan, L., Shen, Z., and Taylor, N.S. (1995). Identification of 

widespread Helicobacter hepaticus infection in feces in commercial mouse colonies by culture and PCR 

assay. J. Clin. Microbiol. 33, 2968-2972. 
AZT and AZT/"-Interferon A/D, NTP TR 469 351 

Sills, R.C., Hong, H.L., Greenwell, A., Herbert, R.A., Boorman, G.A., and Devereux, T.R. (1995). 

Increased frequency of K-ras mutations in lung neoplasms from female B6C3F1 mice exposed to ozone for
 

24 or 30 months. Carcinogenesis 16, 1623-1628.
 

Sipowicz, M.A., Weghorst, C.M., Shio, Y.-H., Buzard, G.S., Calvert, R.J., Anver, M.R.,
 

Anderson, L.M., and Rice, J.M. (1997). Lack of p53 and ras mutations in Helicobacter hepaticus-induced
 

liver tumors in A/JCr mice. Carcinogenesis 18, 233-236.
 

Taylor, N.S., Fox, J.G., and Yan, L. (1995). In-vitro hepatotoxic factor in Helicobacter hepaticus,
 

H. pylori and other Helicobacter species. J. Med. Microbiol. 42, 48-52. 

Ward, J.M., Anver, M.R., Haines, D.C., Tully, J.G., Jr., Collins, M.J., Jr., Gorelick, P.L., 

Anderson, L., Rice, J.M., and Russell, R.J. (1993). A unique hepatitis in mice associated with a helical 

bacterium. Toxicol. Pathol. 21, 591. (Abstr.) 

Ward, J.M., Fox, J.G., Anver, M.R., Haines, D.C., George, C.V., Collins, M.J., Jr., Gorelick, P.L., 

Nagashima, K., Gonda, M.A., Gilden, R.V., Tully, J.G., Russell, R.J., Benveniste, R.E., Paster, B.J., 

Dewhirst, F.E., Donovan, J.C., Anderson, L.M., and Rice, J.M. (1994a). Chronic active hepatitis and 

associated liver tumors in mice caused by a persistent bacterial infection with a novel Helicobacter species. 

J. Natl. Cancer Inst. 86, 1222-1227. 

Ward, J.M., Anver, M.R., Haines, D.C., and Benveniste, R.E. (1994b). Chronic active hepatitis in mice 

caused by Helicobacter hepaticus. Am. J. Pathol. 145, 959-968. 

Ward, J.M., Benveniste, R.E., Fox, C.H., Battles, J.K., Gonda, M.A., and Tully, J.G. (1996). 

Autoimmunity in chronic active Helicobacter hepatitis of mice. Am. J. Pathol. 148, 509-517. 

Wotherspoon, A.C., Doglioni, C., Diss, T.C., Pan, L., Moschini, A., de Boni, M., and Isaacson, P.G. 

(1993). Regression of primary low-grade B-cell gastric lymphoma of mucosa-associated lymphoid tissue 

type after eradication of Helicobacter pylori. Lancet 342, 575-577. 
352 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE R1 

Incidence of Helicobacter hepaticus-Associated Hepatitis in Control B6C3F1 Mice

from Nine NTP 2-Year Studiesa 

Incidence of Hepatitis (%) 

Study Males Females 

Sodium xylenesulfonate 78 4 

AZT/5,000 U "-interferon A/D 76 4 

Cobalt sulfate heptahydrate 72 8 

AZT/500 U "-interferon A/D 66 0 

Chloroprene 54 0 

Theophylline 32 0 

"-Interferon A/D 22 4 

Triethanolamine 20 0 

AZT 16 2 

Average 48 2 

a Includes regeneration and mild to marked (excludes minimal) chronic inflammation, karyomegaly, oval cell hyperplasia, and bile duct 

hyperplasia. AZT=3N-azido-3N-deoxythymidine 

TABLE R2 

Identification of Helicobacter hepaticus with PCR-RFLP-Based Assays in Control B6C3F1 Mice

from 32 NTP 2-Year Studies and Three NTP 13-Week Studiesa 

H. hepaticus-Positive Studiesb 

Type of Sample Total Affected Unaffected 

Studies Studies Studies 

13-Week Studies 

Formalin-fixed liver 3 — 1/3c 

2-Year Studies 

Frozen liver 22 3/3 3/19 

Formalin-fixed liver 10 1/6c 0/4 

a PCR-RFLP=polymerase chain reaction-restriction fragment length polymorphism b	 Number of H. hepaticus-positive studies/number of affected or unaffected studies. Affected studies are those in which hepatitis typical of 

that associated with H. hepaticus infection occurred in many male mice. 

Only one animal in the positive study was positive for H. hepaticus. c 
AZT and AZT/"-Interferon A/D, NTP TR 469 353 

TABLE R3 

Comparison of Neoplasm Incidences in Control B6C3F1 Mice

from Helicobacter hepaticus-Affected and Unaffected NTP 2-Year Studies 

Males Females 

Affected Unaffected Affected Unaffected 

Studiesa Studies Studies Studies 

Number of studies 9 26 9 26 

Survival (%) 64 71 68 68 

12-Month body wt (g) 48.0 48.3 48.1 47.0 

Neoplasm incidence (%) 

Liver 71.3* 54.8 50.3 40.5 

Lung 26.6 23.2 7.6 10.3 

Pituitary gland 0.4 0.8 14.7 14.3 

Harderian gland 5.6 6.1 6.0 4.9 

Lymphoma 6.9 6.3 16.2 15.5 

Circulatory system 9.8 6.0 5.3 4.7

 liver only 7.1* 2.5 — — 

All benign 61.8 57.2 59.1 54.6 

All malignant 61.3* 40.9 50.0 44.2 

All neoplasms 88.0* 77.4 82.7 75.4 

* Significantly different (P#0.05) from the unaffected studies a Affected studies are those in which hepatitis typical of that associated with H. hepaticus infection occurred in many male mice. 
354 AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE R4 

Liver Neoplasm Incidences and Body Weights of Control B6C3F1 Mice

in Relation to Study Start Dates of Helicobacter hepaticus-Affected and Unaffected NTP 2-Year Studiesa 

Liver Neoplasm Incidence (%) Mean Body Weight (g) 

Study Start Date Affected Unaffected Affected Unaffected a Studies Studies Studies Studies 

Male 

April to September 1988 — 43.8 (8)b — 46.2 (8) 

October 1988 62.0 (1) — 48.3 (1) — 

November 1988 to September 1989 — 52.6 (7) — 48.7 (7) 

October 1989 to June 1990 — 61.2 (5) — 48.9 (5) 

July 1990 to January 1991 72.5 (8) 66.2 (4) 48.0 (8) 49.0 (4) 

February 1991 to April 1992 — 68.0 (2) — 52.8 (2) 

Average 71.3 54.8 48.0 48.3 

Female 

April to September 1988 — 31.1 (8) — 44.8 (8) 

October 1988 46.0 (1) — 46.4 (1) — 

November 1988 to September 1989 — 39.9 (7) — 47.2 (7) 

October 1989 to June 1990 — 38.6 (5) — 45.9 (5) 

July 1990 to January 1991 50.9 (8) 54.2 (4) 48.3 (8) 48.0 (4) 

February 1991 to April 1992 — 58.0 (2) — 55.6 (2) 

Average 50.3 40.5 48.1 47.0 

a Includes nine affected studies (those in which hepatitis typical of that associated with H. hepaticus infection occurred in many male mice) and 

26 unaffected studies 

b Number of studies is given in parentheses. 
AZT and AZT/"-Interferon A/D, NTP TR 469 355 

TABLE R5 

Association of Liver Neoplasm Incidence and Severity of Helicobacter hepaticus-Associated Hepatitis a in Control B6C3F Mice from Nine Affected NTP 2-Year Studies 1 

Liver Neoplasm Incidence 

Severity of Hepatitis Males Females 

Absent 

Minimal 

Mild/moderate 

Significance of association 

101/175 (58%) 

44/57 (77%) 

176/218 (81%) 

P<0.05 

196/396 (49%) 

23/42 (55%) 

7/11 (64%) 

NSb 

a Affected studies are those in which hepatitis typical of that associated with H. hepaticus infection occurred in many male mice. b NS=not significant 

TABLE R6 

H-ras Codon 61 AAA Mutations in Spontaneous Liver Neoplasms in Control B6C3F1 Mice

from Helicobacter hepaticus-Affected and Unaffected NTP 2-Year Studies 

a Study Affected H-ras AAA Mutations 

Male 

Cobalt sulfate heptahydrate + 0/10 (0%) 

Chloroprene + 1/13 (8%) 

Triethanolamine + 1/10 (10%) 

Oxazepam — 7/18 (39%) 

Diethanolamine — 4/16 (25%) 

Historical control database 106/333 (32%) 

Female 

Chloroprene + 0/10 (0%) 

Triethanolamine + 1/15 (7%) 

Diethanolamine — 1/11 (9%) 

Historical control database 106/333 (32%) 

a +=affected; — =not affected. Affected studies are those in which hepatitis typical of that associated with H. hepaticus infection occurred in 

many male mice. 
356 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE R7 a Proliferating Cell Nuclear Antigen Labeling Indices in the Liver of Control B6C3F1 Mice

Hepatitis No. of PCNA Labeling Average PCNA 

Animals Indexb Labeling Indexc 

Male 

Cobalt sulfate heptahydrated + 15 0.535 ± 0.129 

Chloroprened + 12 1.452 ± 0.386 

d Triethanolamine	 + 9 1.215 ± 0.374 1.011 

Cobalt sulfate heptahydrate — 7 0.175 ± 0.117 

Chloroprene — 10 0.296 ± 0.124 

Triethanolamine — 12 0.100 ± 0.042 0.186 

9 e 1-Trans-delta -tetrahydrocannabinol — 15 0.042 ± 0.011 

Scopolamine hydrobromide trihydratef — 14 0.043 ± 0.012 

Methyleugenolf — 14 0.077 ± 0.020 

Mouse life-span studyf — 15 0.217 ± 0.880 

Female 

Cobalt sulfate heptahydrate + 5 0.161 ± 0.062 

Cobalt sulfate heptahydrate — 17 0.055 ± 0.015 

Chloroprene — 12 0.154 ± 0.050 

Triethanolamine — 12 0.138 ± 0.053 0.108 

9 1-Trans-delta -tetrahydrocannabinol — 13 0.156 ± 0.047 

Scopolamine hydrobromide trihydrate — 15 0.032 ± 0.009 

a A portion of these data are presented in Nyska et al. (1997). +=hepatitis present; — =no hepatitis present b	 Mean ± standard error; PCNA=proliferating cell nuclear antigen 

Average of the mean labeling indices for animals from all three studies d	 Affected study (one in which hepatitis typical of that associated with H. hepaticus occurred in many male mice) e Unaffected study (one in which the typical hepatitis did not occur in mice) f	 Unaffected study with no typical hepatitis, but positive for H. hepaticus by polymerase chain reaction-restriction fragment length 

polymorphism-based assay 
357 

c 

AZT and AZT/"-Interferon A/D, NTP TR 469 

TABLE R8 

Summary of Target Sites of Carcinogenicity in B6C3F Mice from NTP 2-Year Studies 1 

with Helicobacter hepaticus-Associated Hepatitis 

Males	 Females 

Chloroprene Lung Lung 

Circulatory systema Circulatory system 

Harderian gland Harderian gland 

Forestomach Forestomach 

Kidney Liver 

Skin 

Mesentery 

Zymbal’s gland 

Mammary gland 

Cobalt sulfate heptahydrateb Lung Lung 

Triethanolamine Liver Liver 

AZTc None Vagina 

Sodium xylenesulfonate None None 

Theophylline None None 

a Hemangioma and hemangiosarcoma of the liver were excluded from the analysis in males. b	 An apparent treatment-related increase in the incidence of hemangiosarcoma of the liver was discounted in male mice because of the presence 

of H. hepaticus. 

AZT=3N-azido-3N-deoxythymidine. Includes four studies: AZT; "-interferon A/D; AZT/500 U "-interferon A/D; and AZT/5,000 U 

"-interferon A/D 
358 AZT and AZT/"-Interferon A/D, NTP TR 469