1978 

National Cancer Institute 

CARCIIMOGENESIS 

Technical Report Series 

No. 72 

BIOASSAY OF 

PHENOXYBENZAMINE HYDROCHLORIDE 

FOR POSSIBLE CARCINOGENICITY 

CAS No. 63-92-3 

NCI-CG-TR-72 

U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE 

Public Health Service 

National Institutes of Health 

BIOASSAY OF
 

PHENOXYBENZAMINE HYDROCHLORIDE
 

FOR POSSIBLE CARCINOGENICITY
 

Carcinogenesis Testing Program
 

Division of Cancer Cause and Prevention
 

National Cancer Institute
 

National Institutes of Health
 

Bethesda, Maryland 20014
 

U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
 

Public Health Service
 

National Institutes of Health
 

DHEW Publication No. (NIH) 78-1322
 

BIOASSAY OF
 

PHENOXYBENZAMINE HYDROCHLORIDE
 

FOR POSSIBLE CARCINOGENICITY
 

Carcinogenesis Testing Program
 

Division of Cancer Cause and Prevention
 

National Cancer Institute
 

National Institutes of Health
 

FOREWORD; This report presents the results of the bioassay of
 

phenoxybenzamine hydrochloride conducted for the Carcinogenesis
 

Testing Program, Division of Cancer Cause and Prevention,
 

National Cancer Institute (NCI), National Institutes of Health,
 

Bethesda, Maryland. This is one of a series of experiments
 

designed to determine whether selected environmental chemicals
 

have the capacity to produce cancer in animals. Negative
 

results, in which the test animals do not have a greater
 

incidence of cancer than control animals, do not necessarily mean
 

that the test chemical is not a carcinogen, inasmuch as the
 

experiments are conducted under a limited set of circumstances.
 

Positive results demonstrate that the test chemical is
 

carcinogenic for animals under the conditions of the test and
 

indicate that exposure to the chemical is a potential risk to
 

man. The actual determination of the risk to man from animal
 

carcinogens requires a wider analysis.
 

CONTRIBUTORS: The bioassay of phenoxybenzamine hydrochloride
 

was conducted by Southern Research Institute, Birmingham,
 

Alabama, initially under direct contract to NCI and currently
 

under a subcontract to Tracor Jitco, Inc., prime contractor for
 

the NCI Carcinogenesis Testing Program.
 

The experimental design and doses were determined by Drs. D. P.
 

Griswold^, J. D. Prejean^, and J. H. Weisburger2»3. Ms. J.
 

Belzer^ and Mr. I. Brown^ were responsible for the care of the
 

laboratory animals and the administration of the chemical. Data
 

management and retrieval were performed by Ms. C. A. Dominick^-.
 

Histopathologic examinations were performed by Drs. S. D. 

Kosankel and J. C. Peckham^-, and the diagnoses included in this 

report represent their interpretation. 

iii
 
Animal pathology tables and survival tables were compiled at EG&G
 

Mason Research Institute^. The statistical analyses were performed by Dr. J. R. Joiner-*, using methods selected for the
 

bioassay program by Dr. J. J. Gart^. Chemicals used in this
 

bioassay were analyzed under the direction of Dr. E. Murrill',
 

and the analytical results were reviewed by Dr. C. W. Jameson^.
 

This report was prepared at Tracor Jitco^ under the direction of
 

NCI. Those responsible for the report at Tracor Jitco were
 

Dr. Marshall Steinberg, Director of the Bioassay Program; Dr. L.
 

A. Campbell, Deputy Director for Science; Drs. J. F. Robens and
 

C. H. Williams, toxicologists; Dr. R. L. Schueler, pathologist;
 

Dr. G. L. Miller, Ms. L. A. Waitz, and Mr. W. D. Reichardt,
 

bioscience writers; and Dr. E. W. Gunberg, technical editor,
 

assisted by Ms. Y. E. Presley.
 

The statistical analysis was reviewed by members of the
 

Mathematical Statistics and Applied Mathematics Section of NCI .
 

Dr. John J. Gart, Mr. Jun-mo Nam, Dr. Hugh M. Pettigrew, and
 

Dr. Robert E. Tarone.
 

The following other scientists at NCI were responsible for
 

evaluating the bioassay experiment, interpreting the results, and
 

reporting the findings:
 

Dr. Kenneth C. Chu
 

Dr. Cipriano Cueto, Jr.
 

Dr. J. Fielding Douglas
 

Dr. Dawn G. Goodman
 

Dr. Richard A. Griesemer
 

Dr. Harry A. Milman
 

Dr. Thomas W. Orme
 

Dr. Robert A. Squire^
 

Dr. Jerrold M. Ward
 

^Southern Research Institute, 2000 Ninth Avenue South,
 

Birmingham, Alabama.
 

iv 
^Carcinogenesis Testing Program, Division of Cancer Cause and
 

Prevention, National Cancer Institute, National Institutes of
 

Health, Bethesda, Maryland.
 

%ow with the Naylor Dana Institute for Disease Prevention,
 

American Health Foundation, Hammond House Road, Valhalla,
 

New York.
 

^EG&G Mason Research Institute, 1530 East Jefferson Street,
 

Rockville, Maryland.
 

^Tracer Jitco, Inc., 1776 East Jefferson Street, Rockville,
 

Maryland.
 

"Mathematical Statistics and Applied Mathematics Section,
 

Biometry Branch, Field Studies and Statistics, Division of
 

Cancer Cause and Prevention, National Cancer Institute, National
 

Institutes of Health, Bethesda, Maryland.
 

''Midwest Research Institute, 425 Volker Boulevard, Kansas City,
 

Missouri.
 

^Now with the Division of Comparative Medicine, Johns Hopkins
 

University, School of Medicine, Traylor Building, Baltimore,
 

Maryland.
 

V 

SUMMARY
 

A bioassay of phenoxybenzamine hydrochloride for possible
 

carcinogenicity was conducted by administering the test chemical
 

by intraperitoneal injection to Sprague-Dawley rats and B6C3F1
 

mice.
 

Groups of 35 rats of each sex were administered phenoxybenzamine
 

hydrochloride at one of two doses, either 5 or 10 mg/kg body
 

weight, three times per week for 52 weeks, then observed for an
 

additional 31 or 32 weeks. The vehicle used for most of the
 

period of the bioassay was 6% propylene glycol in saline,
 

although other vehicles, including 0.05% polysorbate 80 in
 

saline, were used at the beginning. Controls consisted of groups
 

of 10 vehicle controls and 10 untreated controls of each sex.
 

All surviving rats were killed at 83-85 weeks.
 

Groups of 35 mice of each sex were administered phenoxybenzamine
 

hydrochloride at one of two doses, either 12.5 or 25 mg/kg body
 

weight, three times per week for 50 or 52 weeks, then observed
 

for an additional 31-33 weeks. Controls consisted of groups of
 

15 males and 15 females which were administered the vehicle
 

(vehicle controls), and groups of 14 males and 16 females which
 

were untreated (untreated controls). All surviving mice were
 

killed at 83-85 weeks.
 

Mean body weights of the low-dose male rats, low- and high-dose
 

female rats, and low-dose male and female mice were comparable to
 

those of the untreated and vehicle controls. The mean body
 

weights of the high-dose male rats and the high-dose male and
 

female mice, which died early, were lower than those of the
 

controls.
 

Sarcoma of the abdominal cavity (peritoneum) was found in dosed
 

animals of both species, but did not occur ia either the
 

untreated or vehicle controls. In male rats, this lesion
 

occurred with a significant dose-related trend (P < 0.001), using
 

vehicle controls, and also at significant incidences in direct
 

comparisons of the dosed groups with the vehicle controls
 

vii
 
(controls 0/10, low-dose 11/31, P = 0.027; high-dose 16/20, P <
 

0.001). In female rats, the lesion occurred at a significant
 

incidence in the high-dose group compared with the vehicle
 

controls (controls 0/9, high-dose 16/30, P = 0.004). None were
 

observed among low-dose females.
 

In the mice, sarcoma of the abdominal cavity (peritoneum)
 

occurred at a high and statistically significant incidence in the
 

high-dose groups of each sex compared with vehicle controls
 

(males: controls 0/15, high-dose 17/21, P < 0.001; females:
 

controls 0/13, high-dose 16/20, P < 0.001). None were observed
 

among low-dose groups. The morphology of the sarcoma was similar
 

in the rats and the mice.
 

It is concluded that under the conditions of this bioassay,
 

phenoxybenzamine hydrochloride was carcinogenic (sarcomagenic) 

for the peritoneum of both sexes of Spr ague-D awl ey rats and 

B6C3F1 mice. 

viii
 
TABLE OF CONTENTS
 

I. Introduction
 

II. Materials and Methods
 

A. Chemical
 

B. Dosage Preparation.
 

C. Animals
 

D. Animal Maintenance
 

E. Subchronic Studies
 

F. Designs of Chronic Studies
 

C. Clinical and Pathologic Examinations
 

H. Data Recording and Statistical Analyses..,
 

III. Results - Rats ,
 

A. Body Weights and Clinical Signs (Rats)
 

B. Survival (Rats)
 

C. Pathology (Rats)
 

D. Statistical Analyses of Results (Rats)
 

IV. Results - Mice
 

A. Body Weights and Clinical Signs (Mice)
 

B. Survival (Mice)
 

C. Pathology (Mice)
 

D. Statistical Analyses of .Results (Mice)..
 

V. Discussion.
 

VI. Bibliography
 

APPENDIXES
 

Appendix A Summary of the Incidence of Neoplasms in
 

Rats Given Intraperitoneal Injections of
 

Phenoxybenzamine Hydrochloride.....................
 

Table Al Summary of the Incidence of Neoplasms in
 

Male Rats Given Intraperitoneal Injections of
 

Phenoxybenzamine Hydrochloride.....................
 

Page
 

1
 

3
 

3
 

3
 

4
 

5
 

8
 

9
 

9
 

13
 

19
 

19
 

19
 

22
 

25
 

29
 

29
 

29
 

32
 

34
 

35
 

39
 

41
 

43
 

ix
 
Table A2


Appendix B


Table Bl


Table B2


Appendix C


Table Cl


Table C2


Appendix D


Table Dl


Table D2


Appendix E


 Summary of the Incidence of Neoplasms in Female
 

Rats Given Intraperitoneal Injections of
 

Phenoxybenzamine Hydrochloride
 

 Summary of the Incidence of Neoplasms in
 

Mice Given Intraperitoneal Injections of
 

Phenoxybenzamine Hydrochloride ,
 

 Summary of the Incidence of Neoplasms in
 

Male Mice Given Intraperitoneal Injections of
 

Phenoxybenzamine Hydrochloride
 

 Summary of the Incidence of Neoplasms in
 

Female Mice Given Intraperitoneal Injections of
 

Phenoxybenzamine Hydrochloride.
 

 Summary of the Incidence of Nonneoplastic
 

Lesions in Rats Given Intraperitoneal Injections of
 

Phenoxybenzamine Hydrochloride.
 

 Summary of the Incidence of Nonneoplastic
 

Lesions in Male Rats Given Intraperitoneal
 

Injections of Phenoxybenzamine Hydrochloride.......
 

 Summary of the Incidence of Nonneoplastic
 

Lesions in Female Rats Given Intraperitoneal
 

Injections of Phenoxybenzamine Hydrochloride.......
 

 Summary of the Incidence of Nonneoplastic
 

Lesions in Mice Given Intraperitoneal
 

Injections of Phenoxybenzamine Hydrochloride.......
 

 Summary of the Incidence of Nonneoplastic
 

Lesions in Male Mice Given Intraperitonejal
 

Injections of Phenoxybenzamine Hydrochloride
 

 Summary of the Incidence of Nonneoplastic
 

Lesions in Female Mice Given Intraperitoneal
 

Injections of Phenoxybenzamine Hydrochloride.......
 

 Analyses of the Incidence of Primary Tumors
 

in Rats Treated with Phenoxybenzamine
 

Hydrochloride
 

Page
 

46
 

49
 

51
 

54
 

57
 

59
 

62
 

65
 

67
 

70
 

73
 

x
 
Page 

Table El Analyses of the Incidence of Primary Tumors 

in Male Rats Treated with Phenoxybenzamine 

Hydrochloride 75 

Table E2 Analyses of the Incidence of Primary Tumors 

in Female Rats Treated with Phenoxybenzamine 

Hydrochloride. 77 

Appendix F Analyses of the Incidence of Primary Tumors 

in Mice Treated with Phenoxybenzamine 

Hydrochloride. 81 

Table Fl Analyses of the Incidence of Primary Tumors 

in Male Mice Treated with Phenoxybenzamine 

Hydrochloride 83 

Table F2 Analyses of the Incidence of Primary Tumors 

in Female Mice Treated with Phenoxybenzamine 

Hydrochloride 86 

TABLES 

Table 1 Design of Chronic Studies of 

Phenoxybenzamine Hydrochloride in Rats. 10 

Table 2 Design of Chronic Studies of 

Phenoxybenzamine Hydrochloride in Mice. 11 

FIGURES 

Figure 1 Growth Curves for Rats Treated with 

Phenoxybenzamine Hydrochloride. 20 

Figure 2 Survival Curves for Rats Treated with 

Phenoxybenzamine Hydrochloride 21 

Figure 3 Growth Curves for Mice Treated with 

Phenoxybenzamine Hydrochloride 30 

Figure 4 Survival Curves for Mice Treated with 

Phenoxybenzamine Hydrochloride. 31 

xi
 
I. INTRODUCTION
 

Phenoxybenzamine hydrochloride (CAS 63-92-3; NCI CO1661) is an
 

antihypertensive agent that is used in controlling specific
 

hypertensive crises such as those that result from high blood
 

levels of sympathomimetic amines. Chemically, phenoxybenzamine
 

undergoes cyclization and conversion to a reactive
 

ethyleneimmonium intermediate. This intermediate binds almost
 

irreversibly to alpha-adrenergic receptors in the autonomic
 

nervous system, blocking further stimulation of these receptors
 

by sympathetic nerves, or by sympathomimetic amines such as
 

epinephrine or norepinephrine. Since these receptors control
 

tension in vascular smooth muscle, peripheral blood pressure is
 

reduced (Carrier, 1972; Goldstein et al., 1974; Nickerson and
 

Collier, 1975).
 

Phenoxybenzamine hydrochloride is administered orally Ln doses of
 

20-200 rag/day, or by slow intravenous infusion at a dose of 1.0
 

mg/kg. It is used principally to manage hypertension associated
 

with inoperable pheochromocytoma which causes excessive adrenal
 

secretion of epinephrine and norepinephrine. This therapy may be
 

extended for several years. Phenoxybenzamine hydrochloride is
 

also recommended in the treatment of some peripheral vascular
 

diseases such as Raynaud's syndrome, acrocyanosis, and frostbite
 

sequelae (Nickerson and Collier, 1975; Smith, Kline, and French,
 

1
 
1977). Phenoxybenzamine hydrochloride was selected for testing as
 

a part of the efforts of the Carcinogenesis Testing Program to
 

investigate drugs that may be used for prolonged periods in
 

humans.
 

2
 
II. MATERIALS AND METHODS
 

A. Chemical
 

Phenoxybenzamine hydrochloride (N-(2-chloroethyl)-N-(l-methyl2-phenoxyethyl)benzylamine hydrochloride) was obtained in two
 

batches for the chronic studies (Lot Nos. 3-9DI-2 and
 

688-A-1-1DI) from the Smith, Kline, and French Laboratories,
 

Philadelphia, Pennsylvania. The identity and purity of Lot No.
 

688-A-1-1DI was confirmed in analyses at the Midwest Research
 

Institute. The melting point was 137-140°C, conforming to the
 

published value of 138-140°C (Kerwin and Ullyot, 1952).
 

Elemental analyses (C, H, N, Cl) were consistent with
 

C18^23^12^0» tne molecular formula for phenoxybenzamine
 

hydrochloride. Nuclear magnetic resonance, infrared, and
 

ultraviolet spectra were in agreement with the structure and
 

matched the spectra given in the literature (Sadtler Standard
 

Spectra, 1966; Kracmar et al., 1966).
 

The chemical was stored at room temperature.
 

B. Dosage Preparation
 

Because of the difficulty encountered in maintaining the phenoxybenzamine hydrochloride in suspension, several different vehicles
 

were used during the chronic studies. The procedure was to mix
 

3
 
the chemical with the vehicle in a Potter-Elvehjem tissue grinder
 

for 20 seconds. Each concentration (0.125, 0.25, 0.2, and 0.4%)
 

was prepared separately. The test suspensions were prepared
 

daily and administered within 15 minutes of preparation. The
 

suspensions of the test chemical administered to rats was
 

contained in phosphate-buffered isotonic (pH 6.9) saline for one
 

week, 0.05% polysorbate in phosphate-buffered saline (pH 6.9) for
 

the next 13 weeks, saline only for one week, and 6% propylene
 

glycol in saline for the remaining 37 weeks. Suspensions for
 

mice were prepared with 0.05% polysorbate 80 in phosphate-


buffered saline (pH 6.9) for the first 10 weeks and with 6%
 

propylene glycol in saline for the remaining 42 weeks of the
 

bioassay.
 

C. Animals
 

For the subchronic studies, female Sprague-Dawley rats and male
 

Swiss mice were obtained from Charles River Breeding
 

Laboratories, Inc., Wilmington, Massachusetts.
 

For the chronic studies, male and female Sprague-Dawley rats and
 

B6C3F1 mice were obtained from Charles River Laboratories under a
 

contract with the Division of Cancer Treatment, National Cancer
 

Institute. On arrival at the laboratory, animals were 4-6 weeks
 

of age. All animals were quarantined, rats for 7 days and mice
 

4
 
for approximately 14 days. Animals with no visible signs of
 

disease were assigned to control or dosed groups and earmarked
 

for individual identification.
 

D. Animal Maintenance
 

All animals were housed in temperature- and humidity-controlled
 

rooms. The temperature range was 20-24°C, and the relative
 

humidity was maintained at 40-60%. Room air was changed 15 times
 

per hour and passed through both intake and exhaust fiberglass
 

roughing filters. In addition to natural light, illumination was
 

provided by fluorescent light for 9 hours per day. Wayne® Lab
 

Blox (Allied Mills, Inc., Chicago, 111.) and water were supplied
 

daily and were available ad libitum.
 

Rats were housed five per cage and mice seven per cage in solid-


bottom stainless steel cages (Hahn Roofing and Sheet Metal Co.,
 

Birmingham, Ala.). The rat cages were provided with Iso-Dri®
 

hardwood chip bedding (Carworth, Edison, N.J.), arid, beginning at
 

week 14, cage tops were covered with disposable filter bonnets;
 

mouse cages were provided with Sterolit® clay bedding (Englehard
 

Mineral and Chemical Co., New York, N.Y.). Bedding was replaced
 

once per week; cages, water bottles, and feeders were sanitized
 

at 82°C once per week; racks were cleaned once per week.
 

The rats and mice were housed in separate rooms. Control animals
 

5
 
were housed with respective dosed animals. Animals administered
 

phenoxybenzamine hydrochloride were maintained in the same rooms
 

as animals of the same species being administered the following
 

chemicals:
 

RATS
 

Gavage Studies
 

cholesterol (p-(bis(2-chloroethyl)amino)phenyl)acetate
 

(phenesterin) (CAS 3546-10-9)
 

estradiol bis((p-(bis(2-chloroethyl)amino)phenyl)acetate)
 

(estradiol mustard) (CAS 22966-79-6)
 

Intraperitoneal Injection Studies
 

4'-(9-acridinylamino)methansulfon~m-aniside monohydrochloride
 

(MAAM) (NSC 141549)
 

acronycine (CAS 7008-42-6)
 

5-azacytidine (CAS 320-67-2)
 

beta-2'-deoxy~6-thioguanosine monohydrate (beta-TGdR)
 

(CAS 789-61-7)
 

i,4-butanediol dimethanesulfonate (busulfan) (CAS 55-98-1)
 

emetine dihydrochloride tetrahydrate (CAS 316-42-7)
 

3,3'-iminobis-l-propanol dimethanesulfonate (ester)
 

hydrochloride [IPD] (CAS 3458-22-8)
 

M—4,4'-(1-methyl—1,2~ethanediyl)bis-2,6-piperazinedione
 

UCRF-159) (CAS 21416-87-5)
 

N, 3~-bis(2-chloroethyl)tetrahydro-2H-l,3,2-oxazaphosphorin~2­

amine-2-oxide (isophosphamide) (CAS 3778-73-2)
 

N-(l-methylethyl)-4-((2-methylhydrazino)methyl)benzamide
 

monohydrochloride (procarbazine) (CAS 366-70-1)
 

tris(l-aziridinyl)phosphine sulfide (thio-TEPA) (CAS 52-24-4)
 

2,4,6-tris(dimethylamino)-s-triazine (CAS 645-05-6)
 

adriaraycin (CAS 23214-92-8)
 

MICE
 

.Fee^d_Sjzii.dies_
 

4-acetyl-N-((cyclohexylainino)carbonyl)benzenesulfonamide
 

(acetohexamide) (CAS 968-81-0)
 

anthranilic acid (CAS 118-92-3)
 

6
 
l-butyl-3-(p-tolylsulfonyl)urea (tolbutamide) (CAS 64-77-7)
 

4-chloro-N-((propylamino)carbonyl)benzenesulfonamide
 

(chlorpropamide) (CAS 94-20-2)
 

5-(4-chlorophenyl)-6-ethyl-2,4-pyrimidinediamine
 

(pyrimethamine) (CAS 58-14-0)
 

2,6-diamino-3-(phenylazo)pyridine hydrochloride (phenazopyridine
 

hydrochloride) (CAS 136-40-3)
 

L-tryptophan (CAS 73-22-3)
 

N-9H-fluoren-2-ylacetamide (CAS 53-96-3)
 

N-(p-toluenesulfonyl)-N'-hexamethyleniminourea
 

(tolazamide) (CAS 1156-19-0)
 

1-phenethylbiguanide hydrochloride (phenformin) (CAS 114-86-3)
 

pyrazinecarboxamide (pyrazinamide) (CAS 98-96-4)
 

4,4'-sulfonyldianiline (dapsone) (CAS 80-08-0)
 

4,4'-thiodianiline (CAS 139-65-1)
 

ethionamide (CAS 536-33-4)
 

Gavage Studies
 

cholesterol (p-(bis(2-chloroethyl)amino)phenyl)acetate
 

(phenesterin) (CAS 3546-10-9)
 

estradiol bis((p-(bis(2-chloroethyl)amino)phenyl)acetate)
 

(estradiol mustard) (CAS 22966-79-6)
 

Intraperitoneal Injection Studies
 

4'-(9-acridinylamino)methansulfon-m-aniside monohydrochloride
 

(MAAM) (NSC 141549)
 

acronycine (CAS 7008-42-6)
 

5-azacytidine (CAS 320-67-2)
 

beta-2'-deoxy-6-thioguanosine monohydrate (beta-TGdR)
 

(CAS 789-61-7)
 

1,4-butanediol dimethanesulfonate (busulfan) (CAS 55-98-1)
 

emetine dihydrochloride tetrahydrate (CAS 316-42-7)
 

3,3'-iminobis-l-propanol dimethanesulfonate (ester)
 

hydrochloride [IPD] (CAS 3458-22-8)
 

(+)-4,4'-(l-methyl-l,2-ethanediyl)bis-2,6-piperazinedione
 

(ICRF-159) (CAS 21416-87-5)
 

N,3-bis(2-chloroethyl)tetrahydro-2H-l,3,2-oxazaphosphorin-2­

amine-2-oxide (isophosphamide) (CAS 3778-73-2)
 

N-(l-methylethyl)-4-((2-methylhydrazino)methyl)benzamide
 

monohydrochloride (procarbazine) (CAS 366-70-1)
 

tris(l-aziridinyl)phosphine sulfide (thio-TEPA) (CAS 52-24-4)
 

7
 
E. Subchronic Studies
 

Subchronic studies were conducted to estimate the maximum
 

tolerated doses of phenoxybenzamine hydrochloride, on the basis
 

of which low and high concentrations (hereinafter referred to as
 

"low doses" and "high doses") were determined for use in the
 

chronic study. Phenoxybenzamine hydrochloride was administered
 

in saline by intraperitoneal injection to female Sprague-Dawley
 

rats at doses of 1.5, 3.75, 7.5, 15, or 30 mg/kg body weight and
 

to male Swiss mice at doses of 2.5, 6.25, 12.5, 25, or 50 mg/kg.
 

The animals were injected three times per week for 45 days, then
 

observed for an additional 45 days. Five animals of each species
 

were injected with the chemical at each dose, 10 received saline
 

vehicle by the same route, and 10 were maintained as untreated
 

controls.
 

fe
 

In the rats, one death occurred after 10 weeks at 30 mg/kg.
 

There were no effects on mean body weight gain, but all animals
 

at this dose had abdominal distention, which occurred at week 5.
 

At 15 mg/kg, 3/5 animals haci abdominal distention, but there were
 

no deaths or effects on mean weight gain. There were no deaths
 

related to the administration of the chemical and no effects on
 

mean weight gain at any of the lower doses. Gross necropsy of
 

rats administered 30 mg/kg showed abdominal adhesions in 2/4
 

8
 
animals and small spleens in 2/4 animals. The low and high doses
 

for rats were set at 5 and 10 mg/kg for the chronic studies.
 

All mice receiving 50 mg/kg died. There were no deaths in
 

animals at any other dose tested, nor were mean body weight gains
 

of animals at lower doses different from those of controls. No
 

gross abnormalities were seen in any of the mice at necropsy.
 

The low and high doses for mice were set at 12.5 and 25 mg/kg for
 

the chronic studies.
 

F. Designs of Chronic Studies
 

The designs of the chronic studies are shown in tables 1 and 2.
 

No comparable vehicle-control groups from other studies were
 

available to form pooled-control groups for statistical analysis.
 

G. Clinical and Pathologic Examinations
 

All animals were observed twice daily for signs of toxicity, and
 

animals that were moribund were killed and necropsied, except for
 

those that died prior to day 100, due, presumbly, to toxicity of
 

the test chemical. Rats and mice were weighed individually every
 

2 weeks. Palpation for masses was carried out at each weighing.
 

The pathologic evaluation consisted of gross and microscopic
 

examination of major tissues, major organs, and all gross lesions
 

9
 
Table 1. Design of Chronic Studies of Phenoxybenzatnine
 

Hydrochloride in Rats
 

Sex and
 

Test
 

Group
 

Male
 

Untreated-Control
 

Vehicle-Control0
 

Low-Dose
 

High-Dose
 

Female
 

Untreated-Control
 

Vehicle-Control0
 

Low-Dose
 

High-Dose
 

Initial
 

No. of
 

Animals3
 

10
 

10
 

35
 

35
 

10
 

10
 

35
 

35
 

Phenoxybenzamine
 

Hydrochloride
 

Dosesb
 

(mg/kg)
 

0
 

0
 

5
 

10
 

0
 

0
 

5
 

10
 

Time on Study
 

Dosed Observed
 

(weeks ) (weeks )
 

84
 

52 31-32
 

52 31
 

52 6d
 

84-85
 

52 32
 

52 32
 

52 31
 

a

Males were 35 days of age and females were 42 days of age
 

when placed on study.
 

bphenoxybenzamine hydrochloride was administered intraperitoneally
 

in a vehicle of phosphate-buffered saline for 1 week, 0.05%
 

polysorbate 80 in phosphate-buffered saline for the next 13
 

weeks, saline only for 1 week, and 6% propylene glycol in
 

saline for the remaining 37 weeks. The chemical was administered
 

three times per week at a volume of 0.25 ml/100 g body weight.
 

Doses were based on individual weights.
 

c

Vehicle-control groups received only the vehicles, as described
 

above, at a volume of 0.25 ml/100 g body weight.
 

"The observation period for the high-dose males terminated
 

at the time indicated, due to the death of all animals.
 

10
 
Table 2. Design of Chronic Studies of Phenoxybenzamine

 

Hydrochloride in Mice 

a

Male mice were 41 days of age and females were 55 days of age
 

when placed on study.
 

^Phenoxybenzamine hydrochloride was administered intraperitoneally
 

in a vehicle of 0.05% polysorbate in phosphate-buffered saline
 

for the first 10 weeks, then in a vehicle of 6% propylene glycol
 

in saline for the remaining 42 weeks. The chemical was
 

administered three times per week at a volume of 1 ml/100 g
 

body weight. Doses were based on the mean weights of the
 

animals in each cage.
 

G

Vehicle-control groups received only the vehicles, as
 

described above, at 1 ml/100 g body weight.
 

11
 
from killed animals and from animals found dead. The following
 

tissues were examined microscopically: skin, muscle, lungs and
 

bronchi, trachea, bone and bone marrow, spleen, lymph nodes,
 

thymus, heart, salivary gland, liver, gallbladder and bile duct
 

(mice), pancreas, esophagus, stomach, small intestine, large
 

intestine, kidney, urinary bladder, pituitary, adrenal, thyroid,
 

parathyroid, mammary gland, prostate or uterus, testis or ovary,
 

brain, and sensory organs. Peripheral blood smears were prepared
 

from each animal whenever possible. Occasionally, additional
 

tissues were also examined microscopically. The different
 

tissues were preserved in 10% buffered formalin, embedded in
 

paraffin, sectioned, and stained with hematoxylin and eosin.
 

Special staining techniques were utilized when indicated for more
 

definitive diagnosis.
 

A few tissues from some animals were not examined, particularly
 

from those animals that died early. Also, some animals were
 

missing, cannibalized, or judged to be in such an advanced state
 

of autolysid as to preclude histopathologic evaluation. Thus,
 

the number of animals from which particular organs or tissues
 

were examined microscopically varies, and does not necessarily
 

represent the number of animals that were placed on study in each
 

group.
 

12
 
H. Data Recording and Statistical Analyses
 

Pertinent data on this experiment have been recorded in an automatic data processing system, the Carcinogenesis Bioassay Data
 

System (Linhart et al., 1974). The data elements include descriptive information on the chemicals, animals, experimental design,
 

clinical observations, survival, body weight, and individual
 

pathologic results, as recommended by the International Union
 

Against Cancer (Berenblum, 1969). Data tables were generated for
 

verification of data transcription and for statistical review.
 

These data were analyzed using the statistical techniques
 

described in this section. Those analyses of the experimental
 

results that bear on the possibility of carcinogenicity are
 

discussed in the statistical narrative sections.
 

Probabilities of survival were estimated by the product-limit
 

procedure of Kaplan and Meier (1958) and are presented in this
 

report in the form of graphs. Animals were statistically
 

censored as of the time that they died of other than natural
 

causes or were found to be missing; animals dying from natural
 

causes were not statistically censored. Statistical analyses for
 

a possible dose-related effect on survival used the method of Cox
 

(1972) for testing two groups for equality and Tarone's (1975)
 

extensions of Cox's methods for testing for a dose-related trend.
 

13
 
One-tailed P values have been reported for all tests except the
 

departure from linearity test, which is only reported when its
 

two-tailed P value is less than 0.05.
 

The incidence of neoplastic or nonneoplastic lesions has been
 

given as the ratio of the number of animals bearing such lesions
 

at a specific anatomic site (numerator) to the number of animals
 

in which that site is examined (denominator). In most instances,
 

the denominators included only those animals for which that site
 

was examined histologically. However, when macroscopic examination was required to detect lesions prior to histologic sampling
 

(e.g., skin or mammary tumors), or when lesions could have
 

appeared at multiple sites (e.g., lymphomas), the denominators
 

consist of the numbers of animals necropsied.
 

The purpose of the statistical analyses of tumor incidence is to
 

determine whether animals receiving the test chemical developed a
 

significantly higher proportion of tumors than did the control
 

animals. As a part of these analyses, the one-tailed Fisher
 

exact test (Cox, 1970) was used to compare the tumor incidence of
 

a control group with that of a group of dosed animals at each
 

dose level. When results for a number of dosed groups (k) are
 

compared simultaneously with those for a control group, a
 

correction to ensure an overall significance level of 0.05 may be
 

made. The Bonferroni inequality (Miller, 1966) requires that the
 

14
 
P value for any comparison be less than or equal to 0.05/k. In
 

cases where this correction was used, it is discussed in the
 

narrative section. It is not, however, presented in the tables,
 

where the Fisher exact P values are shown.
 

The Cochran-Armitage test for linear trend in proportions, with
 

continuity correction (Armitage, 1971), was also used. Under the
 

assumption of a linear trend, this test determines if the slope
 

of the dose-response curve is different from zero at the one-


tailed 0.05 level of significance. Unless otherwise noted, the
 

direction of the significant trend is a positive dose relationship. This method also provides a two-tailed test of departure
 

from linear t.rend.
 

A time-adjusted analysis was applied when numerous early deaths
 

resulted from causes that were not associated with the formation
 

of tumors. In this analysis* deaths that occurred before the
 

first tumor was observed were excluded by basing the statistical
 

tests on animals that survived at least 52 weeks, unless a tumor
 

was found at the anatomic site of interest before week 52. When
 

such an early tumor was found, comparisons were based exclusively
 

on animals that survived at least as long as the animal in which
 

the first tumor was found. Once this reduced set of data was
 

obtained, the standard procedures for analyses of the incidence
 

15
 
of tumors (Fisher exact tests, Cochran-Armitage tests, etc.) were
 

followed.
 

When appropriate, life-table methods were used to analyze the
 

incidence of tumors. Curves of the proportions surviving without
 

an observed tumor were computed as in Saffiotti et al. (1972).
 

The week during which an animal died naturally or was sacrificed
 

was entered as the time point of tumor observation. Cox's
 

methods of comparing these curves were used for two groups;
 

Tarone's extension to testing for linear trend was used for three
 

groups. The statistical tests for the incidence of tumors which
 

used life-table methods were one-tailed and, unless otherwise
 

noted, in the direction of a positive dose relationship.
 

Significant departures from linearity (P < 0.05, two-tailed test)
 

were also noted.
 

The approximate 95 percent confidence interval for the relative
 

risk of each dosed group compared with its control was calculated
 

from the exact interval on the odds ratio (Gart, 1971). The
 

relative risk is defined as Pt/Pc where pt is the true binomial
 

probability of the incidence of a specific type of tumor in a
 

dosed group of animals and pc is the true probability of the
 

spontaneous incidence of the same type of tumor in a control
 

group. The hypothesis of equality between the true proportion of
 

a specific tumor in a dosed group and the proportion in a control
 

16
 
group corresponds to a relative risk of unity. Values in excess
 

of unity represent the condition of a larger proportion in the
 

dosed group than in the control.
 

The lower and upper limits of the confidence interval of the
 

relative risk have been included in the tables of statistical
 

analyses. The interpretation of the limits is that in approximately 95% of a large number of identical experiments, the true
 

ratio of the risk in a dosed group of animals to that in a
 

control group would be within the interval calculated from the
 

experiment. When the lower limit of the confidence interval is
 

greater than one, it can be inferred that a statistically
 

significant result (P < 0.025 one-tailed test when the control
 

incidence is not zero, P < 0.050 when the control incidence is
 

zero) has occurred. When the lower limit is less than unity, but
 

the upper limit is greater than unity, the lower limit indicates
 

the absence of a significant result while the upper limit
 

indicates that there is a theoretical possibility of the
 

induction of tumors by the test chemical, which could not be
 

detected under the conditions of this test.
 

17
 

III. RESU I/ISj-_ JRATS
 

A. Body Weights and Clinical Signs (Rats)
 

Mean body weights of the low-dose male and the low- and high-dose
 

female rats were comparable to those of the untreated and vehicle
 

controls throughout the study (figure 1). Mean body weights of
 

the high-dose males were consistently lower than those of the
 

control groups from week 22 until the death of all animals in
 

this group by week 58. Fluctuation in the growth curve may be
 

due to mortality; as the size of a group diminishes, the mean
 

body weight may be subject to variation. A few animals in the
 

high-dose groups (3/35 males and 9/35 females) had distended
 

abdomens, which was the only other sign of toxicity related to
 

the administration of the chemical.
 

To control respiratory disease, oxytetracycline was administered
 

in the drinking water at a dose of 0.6 mg/ml during weeks 14-18
 

and at a dose of 0.3 mg/ml during weeks 18-23.
 

B. Surviyal (RatsJ 

The Kaplan and Meier curves estimating the probabilities of
 

survival for male and female rats administered phenoxybenzamine
 

hydrochloride by intraperitoneal injection at the doses of this
 

bioassay, together with those of the vehicle and untreated
 

controls, are shown in figure 2.
 

19
 
TIME ON STUDY (WEEKS) 

Figure 1. Growth Curves For Rats Treated With Phenoxybenzamine Hydrochloride 

20 
TIME ON STUDY (WEEKS) 

Figure 2. Survival Curves For Rats Treated With Phenoxybenzamine Hydrochloride 

21 
In each sex, the results of the Tarone test for positive dose-


related trend are significant (P < 0.001), and an indicated
 

departure from linear trend is observed in the male rats (P <
 

0.001), because of the steep decrease in survival in the high-


dose male rats, of which none (0/35) lived to the end of the
 

study. From the number started on study, 13/35 (37%) of the
 

low-dose males and at least 80% of the vehicle- (8/10 [80%]) and
 

untreated-control (10/10) males were alive at termination of the
 

study. The median times on study of the high- and low-dose male
 

rats were 43 weeks and 69 weeks, respectively. Of the high-dose
 

male rats, 27/35 died before week 52 on study, and several tumors
 

were observed before this time, one as early as week 30.
 

Of the number of female rats started on study, 12/35 (34%) of the
 9
 

high-dose group, 23/35 (66%) of the low-dose group, and 9/10
 

(90%) of both the vehicle- and the untreated-control groups lived
 

to the end of the study. The median time on study of the high-


dose female rats was 63 weeks. An adequate number of female rats
 

was at risk for development of late-appearing tumors.
 

C. Pathology (Rats)
 

Histopathologic findings on neoplasms in rats are summarized in
 

Appendix A, tables Al and A2; findings on nonneoplastic lesions
 

are summarized in Appendix C, tables Cl and C2.
 

22
 
A variety of neoplasms occurred in both the control (untreated
 

and vehicle) and dosed groups. Some types of neoplasms occurred
 

only in rats of dosed groups, or with a greater frequency in
 

dosed groups when compared with controls. Most of these tumors
 

either occurred in insignificant numbers or were considered to be
 

common in the Sprague-Dawley rat. However, the high incidence of
 

peritoneal sarcomas in the dosed rats indicated that their
 

presence was related to the intraperitoneal injection of phenoxybenzamine hydrochloride. The incidences of these tumors and of
 

other possible drug-related lesions of the abdominal cavity were
 

as follows:
 

MALES 

Untreated 

Control 

Vehicle 

Control 

Low 

Dose 

High 

Dose 

Number of rats 

examined microscopically (10) (10) (31) (20) 

Abdominal Cavity (Peritoneum) 

sarcoma, NOS* 

chronic inflammation 

granulomatous inflammation 

osseous metaplasia 

0 

0 

0 

0 

0 

0 

0 

0 

11 

4 

0 

0 

16 

1 

1 

1 

FEMALES 

Number of rats 

examined microscopically (29) (29) (35) (30) 

Abdominal Cavity (Peritoneum) 

sarcoma, NOS* 

chronic inflammation 

0 

0 

0 

0 

0 

2 

16 

1 

*Not otherwise specified 

23
 
The peritoneal sarcomas usually were multiple and firmly attached
 

to the serosal surfaces of most abdominal organs.
 

Histologically, the cells comprising these peritoneal sarcomas
 

exhibited a wide range of cellular morphologies. The more highly
 

differentiated cells were spindle shaped and had a large, open-


faced, oval to elongated nucleus and an abundant eosinophilic
 

cytoplasm. These spindle-shaped cells were usually associated
 

with the deposition of a fibrous stroma, probably collagen.
 

Other less differentiated cells were histiocytic in appearance.
 

These cells had a large open-faced nucleus, a prominent
 

eosinophilic nucleolus, and a moderate amount of eosinophilic
 

cytoplasm. The cytoplasmic borders of these cells could not be
 

delineated. The cells that exhibited the most poorly
 

differentiated morphology had a large, oval to elongated nucleus
 

that contained numerous fine clumps of chromatin. The chromatin
 

gave the nuclei a stippled basophilic appearance. These cells
 

had a moderate amount of eosinophilic cytoplasm, and the
 

cytoplasmic borders were poorly defined. Giant cells were
 

commonly observed in the tumors. The peritoneal tumors had often
 

infiltrated the smooth muscle layers of the tubular abdominal
 

organs. However, tumor metastases to the thorax were not
 

observed.
 

In addition to the neoplastic lesions, a number of degenerative,
 

24
 
proliferative, and inflammatory changes were encountered also in
 

animals of the dosed and control groups (Appendix C). Most of
 

these nonneoplastic lesions are commonly seen in aged Sprague-


Dawley rats. However, peritonitis and osseous metaplasia were
 

observed only in dosed rats and were apparently related to the
 

intraperitoneal injection of phenoxybenzamine hydrochloride.
 

The intraperitoneal administration of phenoxybenzamine hydrochloride to Sprague-Dawley rats at both doses of 5 and 10 mg/kg
 

resulted in a high frequency of peritoneal sarcomas. In the
 

judgment of the pathologists, phenoxybenzamine hydrochloride was
 

carcinogenic to Sprague-Dawley rats under the conditions of this
 

study.
 

D. Statistical Analyses of Results (Rats)
 

Tables El and E2 in Appendix E contain the statistical analyses
 

of the incidences of those primary tumors that occurred in at
 

least two animals in one group and with an incidence of at least
 

5% in one or more than one group. The untreated controls are not
 

included in the tables and analyses, because the test conditions
 

of the vehicle controls more closely resembled those of the dosed
 

rats.
 

In each sex, the results of the Cochran-Armitage test for
 

positive dose-related trend in the incidence of sarcoma of the
 

25
 
peritoneum are significant (P < 0.001), and an indicated
 

departure from linear trend is observed (P = 0.009) in female
 

rats, because of the steep increase in incidence in the high-dose
 

group. The Fisher exact test shows that the incidences in the
 

high-dose groups of each sex are significantly higher (P < 0.005)
 

than those in the control groups. The Fisher exact comparison of
 

this incidence of tumors between the low-dose males and the
 

matched controls indicates a probability level of 0.027, which is
 

above the 0.025 level required by the Bonferroni inequality
 

criterion for multiple comparisons. The time-adjusted data on
 

the incidence of this tumor in male rats, using only those
 

animals that died at 30 weeks or more on study, are 0/10 in the
 

vehicle-control group, 11/27 (41%) in the low-dose group, and
 

16/20 (80%) in the high-dose group. Using these incidences, the
 

results of the Cochran-Armitage test are significant (P < 0.001)
 

and those of the Fishe.r exact test are also significant when the
 

incidences in both the low- and high-dose groups are compared
 

with that in the controls (P = 0.015 and P < 0.001,
 

respectively). The statistical conclusion is that the incidence
 

of sarcoma of the peritoneum in rats is related to administration
 

of the test chemical.
 

Significant results in the negative direction are observed in the
 

incidences of pituitary tumors in each sex, where the incidences
 

26
 
in the controls exceed those in the dosed rats, probably because
 

the dosed animals did not live as long as the controls, thus
 

precluding the observation of the development of tumors in the
 

dosed groups.
 

27
 

IV. RESULTS - MICE
 

A. Body Weights and Clinical Signs (Mice)
 

Mean body weights of the low-dose mice of each sex were
 

comparable to those of the vehicle controls for the duration of
 

the study (figure 3); however, the mean body weights of the
 

high-dose mice of each sex were lower than those of the vehicle
 

controls, especially after week 20. The mean body weights of the
 

untreated controls of each sex were higher than those of the
 

corresponding vehicle controls throughout most of the study.
 

Fluctuation in the growth curve may be due to mortality; as the
 

size of a group diminishes, the mean body weight may be subject
 

to variation. No other signs of toxicity related to the
 

administration of the chemical were observed.
 

B. Survival (Mice)
 

The Kaplan and Meier curves estimating the probabilities of
 

survival for male and female mice administered phenoxybenzamine
 

hydrochloride by intraperitoneal injection at the doses of this
 

bioassay, together with those of the vehicle and untreated
 

controls, are shown in figure 4.
 

In each sex, the results of the Tarone test for positive
 

dose-related trend in mortality are significant (P < 0.001), and
 

29
 
TIME ON STUDY fWEEKS) 

Figure 3. Growth Curves For Mice Treated With Phenoxybenzamine Hydrochloride 

30 
70 

TIME ON STUDY (WEEKS) 

Figure 4. Survival Curves For Mice Treated With Phenoxybenzamine Hydrochloride 

31 
an indicated departure from linearity is observed (male mice
 

P = 0.001, female mice P < 0.001), because of the steep decrease
 

in survival in the high-dose animals. Of the male mice started
 

in the bioassay, none (0/35) in the high-dose group, 19/35 (54%)
 

in the low-dose group, all (15/15) in the vehicle-control group,
 

and 12/14 (86%) in the untreated-control group lived to the end
 

of the bioassay. The median time on study of the high-dose male
 

mice was only 39 weeks. All the high-dose males died before 1
 

year on study, and tumors were observed as early as week 32 on
 

study.
 

Of the female mice started in the bioassay, none (0/35) in the
 

high-dose group, but at least 71% in the other three groups
 

studied (25/35 [71%] in low-dose group, 11/15 [73%] in vehicle-


control group, and 13/15 [86%] in untreated-control group), lived
 

to the end of the bioassay. The median time on study of the
 

high-dose female mice was 43 weeks. Of the high-dose female
 

mice, 31/35 died before week 52, and a tumor was found as early
 

as week 34.
 

C. Pathology (Mice)
 

Histopathologic findings on neoplasms in mice are summarized in
 

Appendix B, tables Bl and B2; findings on nonneoplastic lesions
 

are summarized in Appendix D, tables Dl and D2.
 

32
 
A variety of neoplasms occurred in both untreated and vehicle
 

controls and in dosed groups. Some types of neoplasms occurred
 

only in mice of dosed groups, or with greater frequency in dosed
 

groups when compared with controls. Most of these lesions either
 

occurred in insignificant numbers or were considered to be a
 

common finding in B6C3F1 mice. However, the peritoneal sarcomas
 

observed at a high incidence in the dosed mice were considered to
 

be related to the intraperitoneal injection of phenoxybenzamine
 

hydrochloride. These tumors were observed in 17 high-dose male
 

and 16 high-dose female mice, but in no low-dose, untreated- or
 

vehicle-control mice.
 

The morphology and distribution of the peritoneal tumors in
 

B6C3F1 mice were similar to those described for the rats.
 

In addition to the neoplastic lesions, a number of degenerative,
 

proliferative, and inflammatory changes were also encountered in
 

animals of the dosed and control groups (Appendix D). These
 

nonneoplastic lesions are commonly seen in aged B6C3F1 mice.
 

The intraperitoneal administration of phenoxybenzamine hydrochloride to B6C3F1 mice at the high dose of 25 mg/kg resulted in
 

a high frequency of peritoneal sarcomas. In the judgment of the
 

pathologists, phenoxybenzamine hydrochloride was carcinogenic to
 

B6C3F1 mice under the conditions of this study.
 

33
 
D. Statistical Analyses of Results (Mice)
 

Tables Fl and F2 in Appendix F contain the statistical analyses
 

of the incidences of those primary tumors that occurred in at
 

least two animals in one group and with an incidence of at least
 

5% in one or more than one group.
 

In each sex, sarcomas of the peritoneum occurred exclusively in
 

the high-dose group. The results of the Cochran-Armitage test
 

for positive dose-related trend are significant (P < 0.001), and
 

an indicated departure from linear trend is observed (P < 0.001)
 

since there were no sarcomas occurring in the low-dose group.
 

The Fisher exact test shows that the incidences in the high-dose
 

groups are significantly higher (P < 0.001) than those in the
 

controls. The statistical conclusion is that the incidence of
 

sarcomas of the peritoneum is related to administration of the
 

test chemical.
 

No other tumors appeared in a significantly higher proportion in
 

any dosed group compared with that in the controls.
 

34
 
V. DISCUSSION
 

In this bioassay, mean body weights of the dosed groups that
 

survived to the end of the bioassay were comparable to those of
 

the untreated and vehicle controls, while those of the dosed
 

groups that died early (high-dose male rats and high-dose male
 

and female mice) were only slightly lower. None of the high-dose
 

male rats or high-dose male and female mice lived to the end of
 

the bioassay. Rates of survival of the high- and low-dose female
 

rats were 34% and 66%, respectively, and those of the low-dose
 

males were 37%. In the mice, 54% of the low-dose males and 71%
 

of the low-dose females survived to the end of the study. It
 

should also be noted that animals were administered the test
 

chemical for only 52 weeks, which is a shorter period of time
 

than used in current bioassays.
 

Sarcomas of the abdominal cavity (peritoneum) were found in dosed
 

animals of both species, but did not occur in either the
 

untreated or vehicle controls. In male rats, these lesions
 

occurred with a significantly dose-related trend (P < 0.001)
 

using vehicle controls and also at significant incidences in
 

direct comparisons of the dosed groups with the controls
 

(controls 0/10, low-dose 11/31, P = 0.027; high-dose 16/20,
 

P < 0.001). In female rats, the lesions occurred at a
 

significant incidence in the high-dose group compared with the
 

35
 
vehicle controls (controls 0/9, high-dose 16/30, P = 0.004).
 

None were observed among low-dose females.
 

In the mice, sarcomas of the abdominal cavity (peritoneum)
 

occurred at a high and statistically significant incidence in the
 

high-dose groups of each sex compared with the vehicle controls
 

(males: controls 0/15, high-dose 17/21, P < 0.001; females:
 

controls 0/13, high-dose 16/20, P < 0.001). None were observed
 

among low-dose groups. The morphology of the sarcomas found in
 

the mice was similar to that of the sarcomas found in the rats.
 

Since the phenoxybenzamine hydrochloride was administered by
 

intraperitoneal injection, and since the only tumors occurring at
 

statistically significant incidences in either the dosed rats or
 

the dosed mice were found in the peritoneum, the occurrence of
 

these tumors appears to be related to the intraperitoneal
 

injection of the test chemical.
 

The carcinogenic potential of phenoxybenzamine hydrochloride was
 

examined by Stoner et al. (1973) in the strain A mouse pulmonary
 

tumor test system. Four intraperitoneal injections into A/He
 

mice of each sex of total doses of phenoxybenzamine hydrochloride
 

of 200, 100, or 40 mg/kg body weight resulted in a greater
 

incidence of lung tumors in the group administered the middle
 

dose than in the controls by the time the study was terminated
 

36
 
(24 weeks). The investigators found the interpretation of these
 

results difficult, however, because of the higher incidence at
 

the middle dose than at the high dose.
 

It is concluded that under the conditions of this bioassay,
 

phenoxybenzamine hydrochloride was carcinogenic for the
 

peritoneum of both sexes of Sprague-Dawley rats and B6C3F1 mice.
 

37
 

VI. BIBLIOGRAPHY
 

Armitage, P., Statistical Methods in Medical Research, John Wiley
 

& Sons, Inc., New York, 1971, pp. 362-365.
 

Berenblum, I., ed., Carcinogenicity Testing: A Report of the
 

Panel on Carcinogenicity of the Cancer Research Commission
 

of the UICC, Vol. _2, International Union Against Cancer,
 

Geneva, 1969.
 

Carrier, 0., Jr., Adrenergic-blocking drugs. Pharmacology of the
 

Peripheral Autonomic Nervous System, Year Book Medical
 

Publisher, Inc., Chicago, 1972, pp. 112-116.
 

Cox, D. R., Regression models and life tables. J. R. Statist.
 

Soc. B 34 (2):187-220, 1972.
 

Cox, D. R., Analysis of Binary Data, Methuen & Co., Ltd., London,
 

1970, pp. 48-52.
 

Gart, J. J., The comparison of proportions: a review of
 

significance tests, confidence limits and adjustments for
 

stratification. Rev. Int. Statist. Inst. _39 (2):148-169,
 

1971.
 

Goldstein, A., Aronow, L. , and Kalman, S. M., Methods of
 

developing new drugs. In: Principles of Drug Action: The
 

Basis of Pharmacology, John Wiley & Sons, Inc., New York,
 

1974, pp. 6.
 

Kaplan, E. L. and Meier, P., Nonparametric estimation from
 

incomplete observations. J. Am. Statist. Assoc. 53:457-481,
 

1958.
 

Kerwin, J. F. and Ullyot, G. E. , U. S. Patent No. 2,599,000, June
 

3, 1952.
 

Kracmar, J., Kracmarova, J., and Sladkova, J., UV -


Spektrophotometrie in der Arczneimittelkontrolle. Pharmazie
 

11, 460 (1966).
 

Linhart, M. S., Cooper, J. A., Martin, R. L. , Page, N. P., and
 

Peters, J. A., Carcinogenesis bioassay data system. J.
 

Comp. and Biomed. Res. 7:230-248, 1974.
 

39
 
Miller, R., G., Jr., Simultaneous Statistical Inference. McGraw-


Hill Book Co., New York, 1966, pp. 6-10.
 

Nickerson, M. and Collier, B., Drugs inhibiting adrenergic nerves
 

and structures innervated by them. In: The Pharmacological
 

Basis of Therapeutics, Goodman, L. S. and Oilman, A., eds.,
 Macmillan Publishing Co., Inc., New York, 1975, pp. 533-564.
 

Sadtler Standard Spectra, IR No. R498, Sadtler Research
 

Laboratories, Philadelphia, 1966.
 

Saffiotti, U. , Montesano, R., Sellakumar, A. R., Cefis, F. , and
 

Kaufman, D. G., Respiratory tract carcinogenesis in hamsters
 

induced by different numbers of administrations of benzo (a)
 

pyrene and ferric oxide. Cancer Res. 3.2; 1073-1081. 1972.
 

Smith, Kline, and French, Product information: Dibenzyline. In:
 

Physician's Desk Reference. Medical Economics Co., Oradell,
 N. J., 1977, p. 1467.
 

Stoner, G. D. , Shimkin, M. B., Kniazeff, A. J., Weisburger,
 

J. H., Weisburger, E. K., and Gori, G. B., Test for
 

carcinogenicity of food additives and chemotherapeutic
 

agents by the pulmonary tumor response in strain A mice.
 

Cancer Res. 33:3069-3085, 1973.
 

Tarone, R. E., Tests for trend in life table analysis.
 

Biometrika 62 (3):679-682, 1975.
 

40
 
APPENDIX A
 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN
 

RATS GIVEN INTRAPERITONEAL INJECTIONS OF
 

PHENOXYBENZAMINE HYDROCHLORIDE
 

41
 

TABLE A1.

 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN MALE RATS GIVEN 

INTRAPERITONEAL INJECTIONS OF PHENOXYBENZAMINE HYDROCHLORIDE

 

UNTREATED VEHICLE LOW DOSE HIGH DOSE
 

CONTROL CONTROL
 

ANIHALS INITIALLY IN STUDY 10 10 35 35
 

ANIMALS SECROPSIED 10 10 31 20
 

ANIMALS EXAMINED HISTOPATHOLOGICALLY 10 10 31 20
 

INTEGUMENTARY SYSTEM
 

NCNE
 

RESPIRATORY SYSTEM
 

1LUNG (10) (10) (31) (20)
 

SQUAMOUS CELL CARCINOMA. METASTA 1 (3%)
 

HEMATOPCIITIC SYSTEM
 

•MULTIPLE OBGANS" (10) (10) (31) (20)
 

MALIG.LYMPHOMA, HISTIOCYTIC TYPE 1 (3S)
 

fLYBPH NODE OF THORAX (4) (2)
 

CARCINOMA. NOS, HETASTATIC 1
 

SgUAMOUS CELL CARCINOMA, METASTA 1
 

CIRCULATORY SYSTEM
 

NONE
 

DIGESTIVE SYSTEM
 

fLIVER (10) (10) (31) (20)
 

ADENOCARCINOMA, NOS, METASTATIC 1 (3X)
 

tSIOMACH (10) (10) (J1) (14)
 

SQUAMOUS CELL CARCINOMA 1 (3%)
 

ADINOCAKCINOMi, NOS 1 (T%)
 

URINARY SYSTEM
 

"CNE _ _ _ _ _ _ _ _
 

t NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMEER OF ANIHALS NECROPSIED
 

43 
TABLE A1. MALE RATS: NEOPLASMS (CONTINUED) 

UNTREATED

CONTROL

 VEHICLE

 CONTROL 

 LOW DOSE HIGH DOSE 

ENDCCBIN E SYSTEM 

tPITUITAB Y

CHBOMOPHOBE

CHBOMOPHOBE

 ADENOM A

 CABCINOHA

 (8)

 1

 1

 (13%)

 (13*) 

 (9)

 3 (33X) 

 (27) (16) 

BEPEODUC1IVE SYSTEH 

NON E 

HEBVOUS SYSTEH 

NON E 

SPECIAL SENSE ORGANS 

NON E 

HUSCULOSKELETAL SYSTEH 

NON E 

BODY CAVITIES 

*ABDOHINAL CAVITY

SQDAHOOS CELL CABCINOHA, HETASTA

ADBNCCABCINOHA, MOS

ADENOCABCINOHA, NOS, METASTATIC

*PEBITONEUH

SABCOHA, NOS

HESOTHELIOHA, NOS

 (10)

 (10)

 (10)

 (10)

 (31)

 1

 1

 (31)

 11

 4

 (3X) 

 (3X) 

 (35*)

 (13*) 

 (20) 

1 (5X) 

 (20) 

 16 (80*) 

ALL OTHER SYSTEHS 

S3S£ _ _

t NUHBER Of ANIHALS KITH TISSUE EXAMIHED HICBOSCOPICALLY 

* NOHBER OF ANIHALS NECROPSIED 

_ 

44
 
TABLE A1. MALE RATS: NEOPLASMS (CONTINUED) 

UNTREATED VEHICLE LOW DOSE HIGH DOSE
 CONTROL CONTROL
 

ANIMAL DISPOSITION SOHHABY
 

ANIMALS INITIALLY IN STUDY 10 10 35 35
 NATURAL DEATHS 10 22
 

HOBIBUND SACRIFICE 2 8 12
 

SCHEDULED SACRIFICE
 ACCIDENTALLY KILLED It 1
 TERMINAL SACRIFICE 10 8 13
 ANIMAL HISSING
 

9 INCLUDES AUTOLYZED ANIMALS
 

TUMOB SUHBAHY
 

TOTAL ANIMALS WITH PRIMARY TUMORS* 2 3 15 16
 

TOTAL PRIMARY TUHOES 2 3 18 17
 

TOTAL ANIMALS KITH BENIGN TUMORS 1 3
 

TOTAL BENIGN TDHORS 1 3
 

TOTAL ANIMALS WITH MALIGNANT TUMORS 1 12 16
 

TCTAI MALIGNANT TUMORS 1 1U 17
 

TOTAL ANIMALS KITH SECONDARY TUMORS* 3 1
 

TOTAL SECONDARY TUMORS 5 1
 

TOTAL ANIMALS KITH TUMORS UNCERTAIN­ BENIGN OR MALIGNANT 4
 

TOTAL UNCERTAIN TUMORS 4
 

TOTAL ANIMALS WITH TUMORS UNCBRTAIN-


PEIflABY OR METASTATIC
 

TOTAL UNCERTAIN TUMORS
 

* PRIMARY TUMORS: ALL TUHORS EXCEPT SECONDARY TUMORS
 t SECONDARY TUHORS: METASTATIC TUHORS OR TUHORS INVASIVE INTO AN ADJACENT ORGAN
 

45 
UNTREATED

CONTROL

 VEHICLE 

 CONTROL 

LOW DOSE HIGH DOSE 

ANIMALS INITIALLY IN STUDY

ANIMALS NECBOPSIED

ANIHALS EXAMINED HISTOPATHOLOGICALLY

 10

 10

 10

 10 

9 

9 

35

35

35

 35 

 30 

 30 

INTEGUMENTARY SYS1EM 

*SKIN

CARCINOMA. NOS 

*SU3CUT TISSUE

FIBHCMA 

 (10)

 (10)

 (9) 

 (9) 

(35)

1 (3X) 

(35)

2 <6X) 

 (10) 

 (30) 

RESPIBATOBY SYSTEM 

#LUNG

HEMANGIOSABCOMA, HETASTATIC (10) (9) (35)

1 (3%) 

 (30) 

HEMATOEOIETIC SYSTEM 

NCNE 

CIRCULATORY SYSTEM 

NCNI 

DIGESTIVE SYSTEM 

*LIVER

HEMANGIOSABCOMA 

 (10) (9) (35)

1 (3%) 

 (30) 

UBINARY SYSTEM 

NONj 

46
 
TABLE A2. FEMALE RATS: NEOPLASMS (CONTINUED) 

UNTREATED VEHICLE LOW DOSE HIGH DOSE 

CONTROL CONTROL 

ENDOCRIN E 'SYSTEM 

• PITUITAR Y (6) (7) (32) (29) 

CHHOMOPHOBE ADENOM A 1 (17%) 3 (43X) 11 (31%) 1 (3%) 

CHROMOPHOBE CARCINOMA 1 (17%) 1 (3%) 

• ADRENA L (10) (9) (35) (30)

 

EHEOCHROMOCYTOMA , MALIGNAN T 1 (3%)

 

EEPEODUCTIV E SYSTEM 

»MAHHAH Y GLAN D (1C) (9) (35) (30) 

ADENCBA, NOS 1 (3%) 

ADENOCAHCINOHA , NOS 1 (10%) 1 (3%) 

FIBROADENOMA It (l»0%) 2 (22%) 6 (17%) 3 (10*) 

IUTEHUS (10) (9) (35) (11)

 

LEIOMYOM A 1 (3%)

 

NEfiVOU S SYSTE M 

NCN E 

SPECIAL SENSE ORGANS 

HON E 

MUSCULOSKE1ETA L SYSTEM 

NCN £ 

BODY CAVIIIE S 

*AEDCHINA L CAVITY (10) (9) (35) n«>) 

ADENOCARCINOMA . NOS 1 (3% ) 

*P£HITCNEU M (10) (9) (35) (10) 

SARCCMA, NOS 1b (33%) 

* NOBBEH OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMEER OF ANIMALS MECEOPSIED
 

47
 
TABLE A2. FEMALE RATS: NEOPLASMS (CONTINUED) 

UNTREATED VEHICLE LOW DOSE HIGH DOSE
 

CONTROL CONTROL
 

MESOTHJLICHA. MALIGNANT 1 (3X)
 

ALL OTHER SYSTEMS
 

HOME
 

ANIMAL DISPOSITION SUMMARY
 

ANIMALS INITIALLY IN STUDY 10 10 35 35
 NATURAL DEATHS 1 5 9
 

MORIBUND SACRIFICE 1 7 13
 

SCHEDULED SACRIFICE
 ACCIDENTALLY KILLED 1
 

TERMINAL SACRIFICE 9 9 23 12
 ANIMAL MISSING
 

3 INCLUDES AUTOLYZED ANIMALS
 

TUHOH SUMMARY
 

TOTAL ANIMALS HITH PRIMARY TUMOBS* 7 5 20 20
 

TOTAL PRIMARY TUMORS 7 5 26 2«
 

TOTAL ANIMALS HITH BENIGN TUMORS 5 5 15 H
 

TOTAL BENIGN TUMORS 5 5 20 5
 

TOTAL ANIMALS HITH MALIGNANT TOHORS 2 6 16
 

TOTAL MALIGNANT TUMORS 2 6 17
 

TOTAL ANIMALS HITH SECONDARY TUMORS* 1
 

TOTAL SECONDARY TUMORS 1
 

TOTAL ANIMALS HITH TUMORS UNCERTAIN­ EENIGN OB MALIGNANT 2
 

TOTAL UNCERTAIN TUMORS 2
 

TOTAL ANIMALS HITH TOMORS UNCERTAINPBIMARY OR HETASTATIC
 

TOTAL UNCERTAIN TUMORS
 

* PRIMARY TUMORS: ALL TUMORS EXCEPT SECONDARY TOHORS
 t SECONDARY TUMORS: METASTATIC TUMORS OB TUMORS IMVASIVE INTO All ADJACENT ORGAN
 

48
 
APPENDIX B
 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN
 

MICE GIVEN INTRAPERITONEAL INJECTIONS OF
 

PHENOXYBENZAMINE HYDROCHLORIDE
 

49
 

TABLE B1.

 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN MALE MICE GIVEN INTRAPERITONEAL 

INJECTIONS OF PHENOXYBENZAMINE HYDROCHLORIDE 

UNTREATED VEHICLE


CONTROL CONTROL
 

ANIMALS INITIALLY IN STUDY 1H 15
 ANIMALS NECBOPSIED 1» 15


ANIHALS EXAMINED HISTOPATHOLOGICALLY 11 15


INTEGUMENTARY SYSTEM
 

*SUBCOT TISSUE (14) (15)


SARCOMA, NOS
 

RESPIRATORY SYSTEM
 

f LUNG (11) (15)


HEPATOCELLULAfi CAECINOMA, BETAST 1 (7X) 1 (7X)
 

AIVEOLAR/BRONCHIOLAB ADENOMA 1 (7X) 2 (13X)


ALVEOLAR/BRONCHIOLAB CAECINOMA
 

HEMATOECIETIC SYSTEM
 

•MULTIPLE ORGANS (1t) (15)
 MALIG.IYMPHOMA, LYMPHOCYTIC TYPE 1 (7%)
 

ILYBPH NODE OF THORAX (1) (3)
 HEPATOCELLULAR CARCINOMA, METAST 1
 

tHILAfi LYMPH NODE d) (3)
 ADENCCARCINONA, NOS, METASTATIC
 

CIBCULATOBY SYSTEM
 

NONE
 

DIGESTIVI SYSTEM
 

01IVER (1U) (1i»)


HEPAIOCELLUL.AH A.DENQM.A. __ 3 J2JS1 _


t NUMBER OF ANIMALS HITH TISSUE EXAMINED MICROSCOPICALLY
 * NUMBER OF ANIHALS NECBOPSIED
 

 LOW DOSE HIGH DOSE
 

 35 35
 

 30 21
 

 30 21
 

 (30)	 (21)
 

1 (5%)
 

 (30) (21)
 

1 (3X)
 

2 (7%)
 

 (30) (21)
 

 (3)
 

 (3)
 

1
 

 (30) (21)
 

 __ 6_J[20S1 _ _
 

51
 
TABLE B1. MALE MICE: NEOPLASMS (CONTINUED) 

UNTREATED

CONTROL

 VEHICLE

 CONTROL 

 LOW DOSE HIGH DOSE 

HEPATOCELLULAB CARCINOMA 2 (14X) 1 (7X) 

UBINAHY SYSIEH 

NCNE 

ENDOCRINE SYSTEM 

NCNE 

BEPBODOCTIVE SYSTEM 

NCNE 

NERVOUS SYSTEM 

NCNE 

SPECIAL SENSE ORGANS 

NONE 

HUSCOLOSKEIETAL SYSTEM 

NONE 

BODY CAVITIES 

'ABDOMINAL CAVITY

ADENOCARCItiOMA, NOS

SARCOMA, NOS

*PLEUB1

ACENOCABCINOMA, NOS

 (14)

 (14)

 (15)

 (15)

 (30)

 1 (3%) 

 (30)

 1 (3X) 

 (21) 

 17 (81X) 

 (21) 

ALL OTHER SYSTEMS 

t NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY * NUMBER OF ANIMALS NECROPSIED 

52
 
TABLE B1. MALE MICE: NEOPLASMS (CONTINUED)

 

UNTREATED 

CONTROL 

VEHICLE 

CONTROL 

LOW DOSE HIGH DOSE 

ANIHAL DISPOSITION SUMMARY 

ANIMALS IHITIALLY IN STUDY 

NAIUBAL DEATHS 

MORIBUND SACHIFICE SCHEDULED SACRIFICE 

ACCIDENTALLY KILLED 

TERHINAL SACRIFICE 

ANIMAL MISSING 

1U 

2 

12 

15 

15 

35 

11 

5 

19 

35 

25 

10 

9 INCLUDES AUTOLYZED ANIMALS 

THHOB SUMMABY • 

TOTAL ANIMALS HITH PRIMARY TUMORS*

TOTAL PRIMARY TOHORS

 7 

7 

3

3

 7 

 11 

18 

18 

TOTAL ANIHALS WITH BENIGN TUMORS

TOTAL BENIGN 'TOHORS

 U 

 <» 2

2

 6 

7 

TOTAL ANIMALS WITH MALIGNANT TUMORS TOTAL MALIGHANT TUMORS 3 

3 

1

1

 2 t 18 

18 

TOTAL ANIMALS KITH SECONDARY TUMORS*

TOTAL SECONDARY TUHORS

 1

 1

 1

 2

 1 

1 

TOTAL ANIMALS HITH TOHORS UNCEBTAIN­ EENIGN OB MALIGNANT 

TOTAL UNCERTAIN TUHORS 

TOTAL ANIHALS KITH TOMOBS ONCERTAINPBIHABY OR METASTATIC TOTAL UNCERTAIN TUHOBS 

* PBIMABY IOHORS: ALL TOMOHS EXCEPT SECONDARY TOHOBS 

* SECONDARY TURORS: METASTATIC TOHOBS OR TUHORS INVASIVE INTO AN ADJACENT ORGAN 

53
 
TABLE B2. 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN FEMALE MICE GIVEN INTRAPERITONEAL 

INJECTIONS OF PHENOXYBENZAMINE HYOROCHLORIDE 

UNTREATED

CONTROL

 VEHICLE

 CONTROL 

 LOW DOSE HIGH DOSE 

ANIBALS INITIAL!! IN STUDY

ANIBALS HISSING

ANIBALS NECEOPSIED

ANIBALS EXAMINED HISTOPATHOLOGICALLY

 15

 15

 15

 15

 2

 13

 13

 35

 1

 33

 33

 35 

1 

 21 

 20 

INTIGUHENTAHY SYSTEM 

*SDBCUT TISSUE

ADENOCABCINOBA, NOS

 (15) (13)

 1 (8%) 

 (33) (20) 

RESPIRATORY SYSTEM 

ILUNG

ALVEOLAR/BRONCHIOLAR ADENOMA

4LVEOLAR/BRONCHIOLAH CARCINOMA

 (15)

 2 (13%)

 1 (7%) 

 (13)

 1 (8%)

 (33)

 1 (3%) 

 (20) 

HEMATCEOIITIC SYSTEM 

•MULTIPLE ORGANS

MALIG.IYMPHOMA, LYHPHOCYTIC TYPE

LYHPHOCYTIC LEUKEMIA

 (15) (13)

 2 (15%)

 (33)

 2

 1

 (6%) 

 (3%) 

 (20) 

tMEBIASTINAL L. NODE

ADHNOCARCINOBA, NOS, METASTATIC

 (2)

 1 

 (1) (1) 

CIRCULATORY SYSTEM 

NCNE 

DIGESTIVE SYSTEM 

tLIVER

HEPATOCELLULAR ADENOMA

HEEATOCELLULAR CABCINOMA

 (15) (13)

 1 (8%) 

 (33)

 1 (3%) 

 (20) 

URINARY SYSTEM 

t NUMBER OF ANIBALS KITH TISSUE EXAMINED MICROSCOPICALLY 

* NUMBER OF ANIMALS NECROPSIED 

54
 
TABLE B2. FEMALE MICE: NEOPLASMS (CONTINUED) 

UNTREATED

CONTROL

 VEHICLE

 CONTROL 

 LOW DOSE HIGH DOSE 

ENDOCRINE SYSTEM 

*THYEOID

PAPILLARY ADENOCARCINONA

 (10)

 1 (10%) 

 (11) (28) (12) 

REPRODUCTIVE SYSTEM 

IUTEHUS

INDOMETRIAL STROMAL POLYP

 (15) (13) (33)

 1 (3X) 

 (20) 

NERVOUS SYSTEM 

NONE 

SPECIAL SENSE ORGANS 

NONE 

MUSCULOSKEIETAL SYSTEM 

NONE 

BODY CAVITIES 

*ABDCMINAL CAVITY

SA8CCMA, NOS

*PLEUEA

SAECCMA. NOS

 (15)

 (15)

 (13)

 (13)

 (33)

 (33)

 1 (35S) 

 (20) 

 16 (30*) 

 (21) 

ALL CIHE8 SYSTEMS 

* NUMBER OF ANIMALS HITH TISSUE EXAMINED MICROSCOPICALLY 

* NUMBER OF ANIMALS NECROPSIED 

55
 
TABLE B2. FEMALE MICE: NEOPLASMS (CONTINUED) 

UNTREATED VEHICLE LOW DOSE
 

CONTROL CONTROL
 

ANIMAL DISPOSITION SUHHABY
 

ANIHALS INITIALLY IN STUDY 15 15 35
 NATURAL DEATHS 2 2 3
 HOBIBUND SACBIFICE 1 5
 SCHEEULED SACBIFICE 1
 

ACCIDENTALLY KILLED
 

TERMINAL SACBIFICE 13 11 25
 ANIMAL HISSING 2 1
 

* INCLUDES AUTOLYZED ANIHALS
 

TUMOF SUHHABY
 

TOTAL ANIHALS HITH PBIHABY TOHOBS* 4 5 7
 

TOTAL PBIHABY TUHOBS « 5 7
 

TOTAL ANIHALS HITH BENIGN TDHOBS 2 1 3
 TOTAL BENIGN TUHOBS 2 1 3
 

TOTAL ANIHALS HITH HALIQNANT TOHOBS 2 4 n
 TOTAL HALIGNANT TUHOBS 2 4 a
 

TOTAL ANIHALS HITH SECONDABY TOHOBS* 1
 

TOTAL SECONDABY TUHOBS 1
 

TOTAL ANIHALS RITH T08OHS ONCEBTAINBENIGN OB HALIGNANT
 

TOTAL UNCEBTAIN TUHOES
 

TOTAL ANIHALS HITH TDHOBS DNCEBTAINPBIHAEY OB HETASTATIC
 

TOTAL UNCERTAIN TDHOBS
 

* PBIHABY TUHOBS: ALL TUHOBS EXCEPT SECONDABI TUHOBS
 

* SECONDABY TOHOBS: HETASTATIC TDHOBS OB TOHOBS INVASIVE INTO AN ADJACENT OBGAN
 

HIGH DOSE
 

35
 

18
 

15
 

1
 

1
 

16
 

16
 

16
 

16
 

56
 
APPENDIX C
 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS
 

IN RATS GIVEN INTRAPERITONEAL INJECTIONS OF
 

PHENOXYBENZAMINE HYDROCHLORIDE
 

57
 

TABLE C1.

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN MALE RATS GIVEN 

INTRAPERITONEAL INJECTIONS OF PHENOXYBENZAMINE HYDROCHLORIDE 

 LOW DOSE
 

 35
 

 31
 

 31
 

 (31)
 

1 <3X)
 

1 (3X)
 

 (31)
 

 (31)
 

 (31)
 

2 (6%)
 

 (31)
 

7 (23%)
 

 (31)
 

2 (6%)
 

(t)
 

1 (25%)
 

HIGH DOSE
 

35
 

20
 

20
 

(20)
 

(21)
 

(20)
 

(20)
 

1 (5%)
 

(20)
 

(19)
 

1 (5X)
 

(2)
 

ANIHALS INITIALLY IN STUDY
 

AMIHALS NECBOPSIED
 

ANIHALS EXAMINED HISTOPATHOLOGICALLY
 

INTEGOHENTABY SYS1EM
 

• SKIN
 

EPIDEBMAL INCLUSION CYST
 

HYPEBKEBATOSIS
 

•SUECUT TISSUE
 

INFLAMMATION, CHRONIC
 

BESPIBATOBY SYSTEM
 

tLUNG/BBONCHIOLE
 

HYPEBPIASIA. LYMPHOID
 

tLUNG
 

EBCNCHOPNEUHONIA SOPPOBATIVE
 

EBONCHOPNEUtlONIA CHfiONIC SDPPUBA
 

PIGHENTATION. NOS
 

HEBATOPOIETIC SYSTEM
 

IBCNE MARROW
 

ATBOPHY. NOS
 

tSPLEEN
 

HEMATOPOIESIS
 

*MESENTEBIC L. NODE
 

HYPEBPLASIA, LYMPHOID
 

CIBCOLA10HY SYSTEM
 

NONJ
 

UNTREATED
 CONTROL
 

10
 

10
 

10
 

(10)
 

(10)
 

1 (10%)
 

(10)
 

2 (20X)
 

(10)
 

1 (10*)
 

1 (10X)
 

(9)
 

6 (67JC)
 

(10)
 

VEHICLE


CONTROL
 

10


10


10


(10)


(10)


(10)


3 (30%)
 

(10)


2 (20%)


(10)


5 (50%)


(10)


* NUMBEB OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NDMBEB OF ANIMALS NECHOPSIE0
 

59
 
TABLE C1. MALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

UNTREATED 

CONTROL VEHICLE

CONTROL 

 LOW DOSE HIGH DOSE 

DIGESTIVE SYSTEM 

fLIVER HEMORRHAGE INFLAMMATION, NEC80TIZING 

HECROSIS, COAGULATIVE 

LIFOIDOSIS 

 (10) 

1 (10%) 

(10)

1 (10%)

 (31)

1 (3%) 

1 (3%)

 (20) 

2 (10%) 

1 (5%) 

ILIVEB/CENTBILOBULAH

NECROSIS, COAGULATIVE 1IPOIEOSIS 

 (10) (10) (31)

2 (6%)

 (20) 

2 (10%) 

1 (5%) 

• PANCREAS

INFLAMMATION, ACUTE NECROTIZIHG 

 (10) (10) (31) (19) 

1 (5%) 

tPANCREATIC ACINUS

ATROPHY, NOS 

 (10) (10) (J1)

1 (3%) 

 (19) 

•STOMACH CALCIFICATION, METASTATIC  (10) (10) (31)

1 (3%) 

 (19) 

URINARY SYSTEM 

IKIDNEY INFLAMMATION, CHRONIC (10) 

6 (60%) 

(10)

5 (50%)

 (31)

 13 (U2%) 

 (20) 

ENDOCRINE SYSTEM 

*ADEENAL ANGIECTASIS (10) 

1 (10%) 

(10) (31) (20) 

EEPBODUCTIVE SYSTEM 

NONE 

NEHVODS SYSTEM 

HONE 

SPECIAL SENSE ORGANS 

NONi _ 

* NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY 

* NUHEER OF ANIMALS NECBOPSIED 

60
 
TABLE C1. MALE RATS: NONNEOPLASTIC LESIONS (CONTINUED)

UNTREATED

CONTROL

 VEHICLE 

CONTROL 

LOW DOSE HIGH DOSE 

MUSCULOSKEIETAL SYSTEM 

NCNE 

BODY CAVITIES 

*PEHITOHEUM

INFLAMMATION, CHBONIC 

INFLAMMATION. GRANULOMATOUS 

METAPLASIA, OSSEOUS 

(10) (10) (31)

« (13*)

 (20) 

1 (5%) 

1 (5*) 

1 (5%) 

ALL CTHEB SYSTEMS 

NONE 

SPECIAL MORPHOLOGY SUMMARY 

MICROSCOPICALL 

* NUMBER OF ANIMALS NECROPSIED 

NO LESION REPORTED 2 ACCIDENTAL DEATH 

AUTO/8ECBOPSY/HISTO PEBF AUTOLKSIS/NO NECROPSY 

* NDBEEBEEFF OF ANIMALS HITH TISSUE EXAMINED HICBOSCOPICALLY 

3 

1

1 

3

 1 

114 

61
 
TABLE C2. 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN FEMALE RATS 

GIVEN INTRAPERITONEAL INJECTIONS OF PHENOXYBENZAMINE HYDROCHLORIDE 

UNTREATED
 

ANItUIS INITIALLY IN STUDY
 ANIMALS NECROPSIED
 ANIMALS EXAHINBD HISTOPATHOLOGICALLY


INTEGDHEHIABI SYSTEM
 

NCSE
 

BESPIBATORY SYSTEM
 

tTEACHEA
 INFLAMMATION, SUPPDHATIVE
 

INFLAMMATION. CHEONIC
 

tLUNG/BHONCHOS


INFLAMMATION, SUPPOHATIVE
 

tLUNG/BBONCHIOLE
 INFLAHMATION OBLITEBATIVE
 HYPERPLASIA, EPITHELIAL
 HYPEBPLASIA, LYMPHOID


*LUN6


ERONCHOPNEOMONIA SOPPUBATIVE


PHBDHOSIi INTEBSTITIAL CHBONIC


EBONCHOPNEOHONIA CHBONIC SOPPDBA


HEHATOPOIEIIC SYSTEM
 

tBONE BABGOH
 ATBOPHY, NOS


tSPLEEN
 HEHATOPOIESIS
 

tMESENTEBIC L. NODE
 COHGESTIOH, DOS
 

CIBCDLATOEI SYSTEM
 

I«C«I
 

CONTROL
 

 10
 

 10
 

 10
 

 (10)
 

 (10)
 

 (10)
 

2 (20X)
 

 (10)
 

1 (10X)
 

1 (10*)
 

2 (20*)
 

 (10)
 

3 (30X)
 

 (10)
 

VEHICLE LOW DOSE HIGH DOSE 

CONTROL 

10 35 35 

9 35 30 

9 35 30 

(9) (35) (30) 

1 (11X) 

2 (6«) 

(9) (35) (30) 

1 (3X) 

(9) (35) (30) 

1 <3X) 

1 (3*) 

(9) (35) (30) 

1 (3X) 

1 (3X) 

(8) (35) (29) 

3 (38X) 10 (29X) 5 (17X) 

(9) (35) (30) 

1 (3X) 2 (7X) 

(1)

1 (100X) 

 (1) 

* NDMBEB OF ANIH1LS KITS TISSUE EXAMINED HICBOSCOPICALLY
 * HUMBEB OF ANIMALS BECROPSIBD
 

62 
TABLE C2. FEMALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

UNTREATED 

CONTROL 

VEHICLE

CONTROL 

 LOW DOSE HIGH DOSE 

DIGESTIVE SYSTEM 

tLIVEH 

NECROSIS, FOCAL 

ANGIECTASIS 

(10) (9) (35) (30) 

1

1

 (3X) 

 (3X) 

*PANCREATIC ACINUS 

ATBOPHY, NOS 

(10) (9) (35) 

1 (3X) 

(30) 

UBINAEY SYSTEM 

tKIDNEY 

INFLAMMATION, NOS 

PYELONEPHRITIS SUPPURATIVE 

INFLAMMATION, CHRONIC 

(10) 

1 (10X) 

(9) 

2 (22X) 

(35) 

1

7

 (3X) 

 (20X) 

(30) 

1

1

 (3X) 

 (3X) 

ENDCCEINE SYSTEM 

IADRENAL 

ANGIECTASIS 

(10) 

4 (40X) 

(9) 

1 (11X) 

(35) 

3 (9X) 

(30) 

1 <3X) 

EEPEODUCTIVE SYSTEM 

*MAMMABY GLAND 

CYST, NOS 

(10) 

1 (10X) 

(9) (35) 

8 (23X) 

(30) 

3 (10X) 

*VAGINA 

INFLAMMATION, SUPPUBATIVE 

(10) (9) 

1 (11*) 

(35) (30) 

ICEHVIX UTERI 

INFLAMMATION, ACUTE/CHBONIC (10) (9) 

1 (11X) 

(35) (30) 

tOTEEUS/ENDOHETBIUM 

INFLAMMATION, SUPPUBATIVE 

INFLAMMATION, ACUTE/CHBONIC 

INFLAMMATION, CHRONIC SUPPOHATIV 

HYPEBPLASIA, CYSTIC 

METAPLASIA, SQUAMOUS 

(10) 

3 (30X) 

(9) 

4 (4UX) 

1 (11X) 

1 (11X) 

(35) 

5

2

 (14X) 

 (6X) 

(30) 

2

1

 (7X) 

 <3X) 

IOVABY (10) (9) (33) (30) 

* NUHBEB OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY 

* NUMBER OF ANIMALS NECBOPSIED 

63
 
TABLE C2. FEMALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

UNTREATED

CONTROL

 VEHICLE

 CONTROL 

 LOW DOSE HIGH DOSE 

ABSCESS, NOS

INFLAMMATION , CHRONIC SUPPURATI V

 1 (11*) 

1 (11X) 

NERVOU S

NCN E 

 SYSTEM 

SPECIAL

NON E 

 SENS E ORGAN S 

MUSCULOSKELETAL

NCN E 

 SYSTEM 

BOD Y CAVITIE S 

*ABDCMINA L CAVIT Y

SIEATITI S

*PERITCNEU M

INFLAMMATION , CHBCNIC

INFLAMMATION , CHRONIC SUPPURATI V

 (10 )

 (10)

 (9 )

 (9 )

 (35)

 2 (6%) 

 (35 )

 1 (31)

 1 (J% ) 

 (3) ) 

 (30 ) 

1 (37.) 

A LL CIHE B SYSTEM S 

NCN E 

SPECIA L M05PHOLOBY SUMMAR Y 

N C LESIO N REPORTE D

AUTOLYSIS/N O NECROPS Y

 1 1 

1

6 1 r

i 

64
 
APPENDIX D
 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS
 

IN MICE GIVEN INTRAPERITONEAL INJECTIONS OF
 

PHENOXYBENZAMINE HYDROCHLORIDE
 

65
 

TABLE D1.

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN MALE MICE GIVEN 

INTRAPERITONEAL INJECTIONS OF PHENOXYBENZAMINE HYDROCHLORIDE

 

UNTREATED

CONTROL

 VEHICLE

 CONTROL 

 LOW DOSE HIGH DOSE 

ANIMALS INITIALLY IN STUDY

ANIMALS NECBOPSIED

ANIMALS EXAMINED HISTOPATHOLOGICALLY

 14

 14

 14

 15

 15

 15

 35

 30

 30

 35 

 21 

 21 

INTEGUMEN1ABY SYSTEM 

NONE 

RESPIBA10BY SYSTEM 

*LUNG

EBCNCHOPNEUHONIA SDPPIIBATIVE

PNEUMONIA INTEBSTITIAL CHBONIC

 (11) (15)

 1 (7%) 

 (30)

 1 (3%) 

 (21) 

HEHATOEOIETIC SYSTEM 

IBCNE MABBOH

HYPEBPLASIA, HEMATOPOIETIC

 (14)

 1 (7%) 

 (14) (30) (18) 

tSPLEEN

HYPEBPLASIA, HEMATOPOIETIC

HEHATOPOIESIS

 (14)

 1 (7%) 

4 (29%)

 (15)

 1 (7%)

 (30)

 1 (3%)

 (21) 

2 (10%) 

tHESENTEBIC L. NODE

CONGESTION, NOS

INFLAMMATION, SUPPORATIVE

HYPEBPLASIA, LYMPHOID

 (1) (3)

 1 (33%)

 1 (33%) 

 (3) 

1 (33%) 

1 (33%) 

• INGUINAL LYMPH NODE

INFLAMMATION, ACUTE SOPPUBATIVE

 (1) (3) (3) 

1 (33%) 

CIBCULATOBY SYSTEM 

NONE 

DIGESTIVE SYSTEM 

tLIVEE

HIPEBPL^SIA. HODULAR

 (14) (14)

 1 (7%)

 (30)

 1 13%) 

 (21) 

* NUMBE R OF ANIMALS KITH TISSUE EXAMINED MICROSCOPICALLY 

* NUBBEB OF ANIMALS NECBOPSIED 

67
 
TABLE D1. MALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

UNTREATED

CONTROL

 VEHICLE

 CONTROL 

HYPEBPIiSIA. HEMATOPOIETIC 1 <7X) 

tLIVEB CENTRILOBULAH 

HECBOSIS, DOS (1*)

1 (7«) 

 <1«)

OHIBABY SYSTEM
 

iKIDNEY (It) (15)
 HYDRONEPHBOSIS 1 <7X) 1 (7X)


PYELONEPHRITIS SOPPURATIVE 1 <7X)
 

tUEINABY BLADDER (1«) (15)
 INFLAMMATION, CHBONIC
 

ENDCC5INE SYSTEM
 

NONE
 

HEPBOEUCTIVE SYSTEM
 

tPBOSTATE (1«) (15)
 INFLAMMATION, SUPPORATIVE 1 (7S)
 

*SEHIKAL VESICLE (14) (15)
 INFLAMMATION, SUPPUBATIVE 1 (7X) 1 (7%)
 

*EPIDIDYMIS <1«) (15)
 INFLAMMATION, SUPPUBATIVE 1 (7X)
 

NEBVODS SYSTEM
 

NCNE
 

SPECIAL SENSE ORGANS
 

NONE
 

MUSCULOSKEIETAL SYSTEM
 

»2fif_
 

t NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

*	 NUMBER OF ANIMALS NECROPSIED
 

68
 

 LOW DOSE HIGH DOSE
 

 (30) (21)
 

 (30)	 (21)
 

1 (3«)
 

 (30)	 (20)
 

1 (3*)
 

 (30) (19)
 

 (30) (21)
 

 (30) (21)
 
TABLE D1. MALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

UNTREATED

CONTROL

 VEHICLE

 CONTROL 

 LOW DOSE HIGH DOSE 

BODY CAVITIES 

NCNE 

ALL CTHEB SYSTEMS 

NCNE 

SPECIAL HOBPHOLOGY SUMHAHY 

NO LESION REPORTED 3 6

NO NECROPSY PERFORMED

AUTOLYSIS/NO NECfiOPSY

# NUMEER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY * NUMEER OF ANIMALS NECROPSIED 

 20

 5

 3 

7 

7 

69
 
TABLE 02.

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN FEMALE MICE 

GIVEN INTRAPERITONEAL INJECTIONS OF PHENOXYBENZAMINE HYDROCHLORIDE

 

UNTREATED 

CONTROL 

VEHICLE 

CONTROL 

LOW DOSE HIGH DOSE 

ANIMALS INITIALLY IN STUDY 15 ANIMALS HISSING 

ANIMAIS NECROPSIED 15 ANIMALS IXAHINED HISTOPATHOLOGICAI.LY 15 

15 

2 

13 

13 

35

1

33

33

 35 

1 

 20 

 20 

INTEGUHENTABY SYSTEM
 

NCNI
 

RESPIRATORY SYSTEH
 

tLQNG (15) (13) (33) (20)
 

HYPEHPLASIA. LYMPHOID 1 (8X)
 

HEHATOEOIITIC SYSTEM
 

tSPLEEN (15) (13) (33) (20)
 

HEHATOPOIESIS 1 (7X) 1 (3X) 1 (5X)
 

• HJESEHTERIC L. NODE (2) (1) (1)
 

HYPEFPLASIA, LYMPHOID 1 (SOX)
 

ITHXHDS (15) (13) (33) (19)
 

INFLAMMATION. SOPPOHATIVE 1 (7*)
 

CIRCOLATOEY SYSTEH
 

NONE
 

DIGESTIVE SYSTEM
 

•LITER	 (15) (13) (33) (20)
 

NECROSIS, COAGULATI7E 1 <3X)
 

HYPEBPLASIA, HODULAB 1 (3X)
 

•PANCBEATIC ACINUS (15) (12) (33) (19)
 

. ifBPfHI. MOS _.. 1 J5.S1
 

* NUBBB8 OF ANIMALS WITH TISSDB EXAMINED HICBOSCOPICALLY
 

* HOBEBR OF ANIMALS NECROPSIED
 

70
 
TABLE D2. FEMALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

UNTREATED VEHICLE LOW DOSE HIGH DOSE
 

CONTROL CONTROL
 

»ILIUM (15) (13) (33) (19)
 

ULCEB, FOCAL 1 (3«)
 

URINAR Y SYSTEM
 

IKIENEY (15) (13) (33) (20)
 

INFLAMMATION, CHRONIC 1 (3%)
 HYPEBPLASIA, LYMPHOID 1 (8%)
 

tKIENEY/GLOMEBULUS (15) (13) (33) (20)
 

AMYLOIDOSIS 1 (7%)
 

ENDOCEINE SYSTEM
 

NCNI
 

BEPBOCOCTIVE SYSTEM
 

IUTEBUS/ENDOHETBIDH (15) (13) (33) (20)
 

INFLAHHATION, SUPPUBATIVE 1 (7%)
 

HYPEBPLASIA, CYSTIC 12 (80%) 10 (77%) 27 (82%) 2 (10%)
 

IOVABY (15) (13) (33) (20)
 

CYST, NOS 2 (6%)
 

HEMOEBHAGE 1 (5%)
 

HEBOBBHAGIC CYST 1 (3%)
 

NEBVOUS SYSTEM
 

NONE
 

SPECIAL SENSE ORGANS
 

NONE
 

MOSCOLOSKEIETAL SYSTEM
 

HgNJ . , . _ ..... .
 

t NOHBEH OF ANIMALS HITH TISSUE EXAMINED HICBOSCOPICALLY
 

* NUMBER OF ANIMALS NBCFOPSIED
 

71 
TABLE D2. FEMALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

UNTREATED

CONTROL

 VEHICLE

 CONTROL 

 LOW DOSE HIGH DOSE 

BODY CAVITIES 

*ABDCHIHiL CAVITY

STEATITIS

 (15)

 1 (7*) 

 (13) (33) (20) 

*PEBITONEUN

INFLAMMATION , CHBOHIC SUPPURATIV

 (15) (13) (33)

 1 (3X) 

 (20) 

ALL OTHEB SYSTEMS 

NONE 

SPECIAL MORPHOLOGY SUMMAR Y 

N O LESION HEPOBTED

ANIMA L MISSING/HO NECBOPSY

NO NECBOPSY PEBFOBHED

AOTOLYSIS/NO NECBOPSY

 2

 1

 2

 3 

1

 1

3 

1 

6 

8 

t NUMEEH OP ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY 

* NUMBER OF ANIMALS NECHOPSIED 

72 
APPENDIX E
 

ANALYSES OF THE INCIDENCE OF PRIMARY TUMORS IN RATS
 

TREATED WITH PHENOXYBENZAMINE HYDROCHLORIDE
 

73
 

Table El. Analyses of the Incidence of Primary Tumors in Male Rats
 

Treated with Phenoxybenzamine Hydrochloride3
 

Topography; Morphology
 

Pituitary: Chromophobe Adenoma
 

or Carcinoma^
 

P Values0>d
 

Departure from Linear Trend6
 

Relative Risk (Vehicle Control)f
 

Lower Limit
 

Upper Limit
 

v4 

Ul Weeks to First Observed Tumor
 

Peritoneum: Sarcoma, NOS^
 

P Values0 »d
 

Relative Risk (Vehicle Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Vehicle Low High 

Control Dose -«MIM»«

Dose V 

3/9 (33) 0/27 (0) 0/16 (0) 

P = 0.006(N) P = 0.012(N) P = 0.037(N) 

P = 0.011 

0.000 0.000 

0.000 0.000 

0.527 0.863 

__ 

73 

0/10 (0) 11/31 (35) 16/20 (80) 

P < 0.001 P = 0.027 P < 0.001 

Infinite Infinite 

1.204 2.961 

Infinite Infinite 

46 30 
Table El. Analyses of the Incidence of Primary Tumors in Male Rats 

Treated with Phenoxybenzamine Hydrochloride3 

(continued) 

Vehicle Low High
 

Topography; Morphology Control Dose Dose
 

Peritoneum: Mesothelioma^ 0/10 (0) 4/31 (13) 0/20 (0)
 

P Valuesc»d N.S. N.S. N.S.
 

Relative Risk (Vehicle Control)f Infinite
 

Lower Limit 0.334
 —
 Upper Limit Infinite
 —
 

Weeks to First Observed Tumor 83
 —
 

a

Dosed groups received 5 or 10 rag/kg by intraperitoneal injection.
 

—
 

»-j


ON
 

^Number of tumor-bearing animals/number of animals examined at site (percent).
 

°Beneath the incidence of tumors in a control group is the prcbability level for the Cochran-


Armitage test when P < 0.05; otherwise, not significant (N.S.) is indicated. Beneath the
 

incidence of tumors in a dosed group is the probability level for the Fisher exact test for
 

the comparison of that dosed group with the vehicle-control group when P < 0.05; otherwise,
 

not significant (N.S.) is indicated.
 

^A negative trend (N) indicates a lower incidence in a dosed group than in a control group.
 

e

The probability level for departure from linear trend is given when P < 0.05 for any comparison.
 

^The 95% confidence interval of the relative risk between each dosed group and the specified
 

control group.
 
Table E2. Analyses of the Incidence of Primary Tumors in Female Rats

 

Treated with Phenoxybenzamine Hydrochloride3

 

Topography; Morphology
 

Subcutaneous Tissue: Fibroma^3
 

P Valuesc»d
 

Relative Risk (Vehicle Control)f
 

Lower Limit 

Upper Limit 

Weeks to First Observed Tumor 

-J Pituitary: Chromophobe Adenoma ~J 

or Carcinoma^
 

P Values0 »d
 

Relative Risk (Vehicle Control) f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Vehicle Low High 

Control Dose Dose 

0/9 (0) 2/35 (6) 0/30 (0) 

N.S. N.S. N.S. 

__ 

Infinite 

0.085 

Infinite — 

— 

84 — — 

3/7 (43) 12/32 (38) 1/29 (3) 

V = 0.002(N) N.S. P = 0.018(N) 

0.875 0.080 

0.376 0.002 

4.030 0.874 

84 56 83 
Table E2. Analyses of the Incidence of Primary Tumors in Female Rats 

Treated with Phenoxybenzamine Hydrochloride3 

(continued) 

Topography; Morphology
 

Mammary Gland: Fibroadenoma^
 

P Valuesc»d
 

Relative Risk (Vehicle Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Peritoneum: Sarcoma, NOS^
 -«l 

00 

P Valuesc»d
 

Departure from Linear Trend8
 

Relative Risk (Vehicle Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Vehicle Low High 

Control Dose Dose 

2/9 (22) 6/35 (17) 3/30 (10) 

N.S. N.S. N.S. 

0.771 0.450 

0.184 0.067 

7.155 4.926 

84 50 56 

0/9 (0) 0/35 (0) 16/30 (53) 

P < 0.001 N.S. P = 0.004 

P = 0.009 

Infinite —— 1.740 — Infinite — 

45 — — 
Table E2. Analyses of the Incidence of Primary Tumors in Female Rats
 

Treated with Phenoxybenzamine Hydrochloride3
 

(continued)
 

Vehicle Low High
 

Topography; Morphology Control Dose Dose
 

Peritoneum: Mesotheliomab 0/9 (0) 1/35 (3) 2/30 (7)
 

P Valuesc>d N.S. N.S. N.S.
 

Relative Risk (Vehicle Control)f Infinite Infinite
 

Lower Limit 0.015 0.100
 

Upper Limit Infinite Infinite
 

Weeks to First Observed Tumor 56 57
 —
 

a

Dosed groups received 5 or 10 mg/kg by intraperitoneal injection.
 -J 

VD 

^Number of tumor-bearing animals/number of animals examined at site (percent).
 

c

Beneath the incidence of tumors in a control group is the probability level for the Cochran-


Armitage test when P < 0.05; otherwise, not significant (N.S.) is indicated. Beneath the
 

incidence of tumors in a dosed group is the probability level for the Fisher exact test for
 

the comparison of that dosed group with the vehicle-control group when P < 0.05; otherwise,
 

not significant (N.S.) is indicated.
 

d

A negative trend (N) indicates a lower incidence in a dosed group than in a control group.
 

e

The probability level for departure from linear trend is given when P < 0.05 for any comparison.
 

95% confidence interval of the relative risk between each dosed group and the specified
 

control group.
 

APPENDIX F
 

ANALYSES OF THE INCIDENCE OF PRIMARY TUMORS IN MICE
 

TREATED WITH PHENOXYBENZAMINE HYDROCHLORIDE
 

81
 

__ 

__ 

Table Fl. Analyses of the Incidence of Primary Tumors in Male Mice
 

Treated with Phenoxybenzamine Hydrochloridea
 

Vehicle Low High
 

Topography; Morphology Control Dose Dose
 

Lung: Alveolar/Bronchiolar
 

Carcinomab 0/15 (0) 2/30 (7) 0/21 (0)
 

P Valuesc'd N.S. N.S. N.S.
 

Relative Risk (Vehicle Control)f Infinite
 

Lower Limit 0.156
 

Upper Limit Infinite
 —
 

—
 

Weeks to First Observed Tumor — 69
 

oo 

w Lung: Alveolar/Bronchiolar 

Adenoma or Carcinoma^ 2/15 (13) 3/30 (10) 0/21 (0) 

P Valuesc»d N.S. N.S. N.S.
 

Relative Risk (Vehicle Control)f 0.750 0.000
 

Lower Limit 0.099 0.000
 

Upper Limit 8.343 2.319
 

Weeks to First Observed Tumor 84 69
 —
 
__ 

__ 

Table Fl. Analyses of the Incidence of Primary Tumors in

Treated with Phenoxybenzamine Hydrochloridea 

(continued) 

Vehicle Low
 

Topography; Morphology Control Dose
 

Liver: Hepatocellular Adenoma*5 0/14 (0) 6/30 (20)
 

P Valuesc»d N.S. N.S.
 

Departure from Linear Trend6 P = 0.006
 

Relative Risk (Vehicle Control)f Infinite
 

Lower Limit 0.806
 

Upper Limit Infinite
 

Weeks to First Observed Tumor 58
 00

*• 

Liver: Hepatocellular Adenoma
 

or Carcinoma** 1/14 (7) 6/30 (20)
 

P Values0 »d N.S. N.S.
 

Departure from Linear Trend6 P = 0.034
 

Relative Risk (Vehicle Control)f 2.800
 

Lower Limit 0.399
 

Upper Limit 123.635
 

Weeks to First Observed Tumor 82 58
 

 Male Mice 

High
 

Dose
 

0/21 (0)
 

N.S.
 

—
 

—
 

0/21 (0)
 

N.S.
 

0.000
 

0.000
 

12.140
 

—
 
Table Fl. Analyses of the Incidence of Primary Tumors in Male Mice
 

Treated with Phenoxybenzamine Hydrochloridea
 

(continued)
 

Vehicle Low High
 

Topography: Morphology Control Dose Dose
 

Abdominal Cavity: Sarcoma, NOSb 0/15 (0) 0/30 (0) 17/21 (81)
 

P Valuesc»d P < 0.001 N.S. P < 0.001
 

Departure from Linear Trend6 P < 0.001
 

Relative Risk (Vehicle Control)f Infinite
 

Lower Limit 4.345
 

Upper Limit Infinite
 

oo Weeks to First Observed Tumor — 32 

l_n 

a

Dosed groups received 12.5 or 25 mg/kg by intraperitoneal injection.
 

^Number of tumor-bearing animals/number of animals examined at site (percent).
 

°Beneath the incidence of tumors in a control group is the probability level for the Cochran-


Armitage test when P < 0.05; otherwise, not significant (N.S.) is indicated. Beneath the
 

incidence of tumors in a dosed group is the probability level for the Fisher exact test for
 

the comparison of that dosed group with the vehicle-control group when P < 0.05; otherwise,
 

not significant (N.S.) is indicated.
 

"•A negative trend (N) indicates a lower incidence in a dosed group than in a control group.
 

e

The probability level for departure from linear trend is given when P < 0.05 for any comparison.
 

95% confidence interval of the relative risk between each dosed group and the specified
 

control group.
 
__ 

Table F2. Analyses of the Incidence of Primary Tumors in Female Mice 

Treated with Phenoxybenzamine Hydrochloridea 

Topography: Morphology


Hematopoietic System: Lymphoma^3


P Valuesc»d


Relative Risk (Vehicle Control)f
 

Lower Limit 

Upper Limit 

Weeks to First Observed Tumor

Hematopoietic System: Lymphoma oo 

or Leukemiab

P Valuesc»d

Relative Risk (Vehicle Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor


Vehicle
 

 Control
 

 2/13 (15)
 

 N.S.
 

 62
 

 2/13 (15)
 

 N.S.
 

 62
 

Low
 

Dose
 

2/33 (6)
 

N.S.
 

0.394
 

0.033
 

5.070
 

84
 

3/33 (9)
 

N.S.
 

0.591
 

0.080
 

6.583
 

76
 

High
 

Dose
 

0/20 (0)
 

N.S.
 

0.000
 

0.000
 

2.100
 

0/20 (0)
 

N.S.
 

0.000
 

0.000
 

2.100
 

—
 
Table F2. Analyses of the Incidence of Primary Tumors in Female Mice
 

Treated with Phenoxybenzamine Hydrochloride3
 

(continued)
 

Vehicle Low High
 

Topogjraphv^ Morphology Control Dose Dose
 

Abdominal Cavity: Sarcoma, NOSb 0/13 (0) 0/33 (0) 16/20 (80)
 

P Valuesc>d P < 0.001 ' N.S. P < 0.001
 

Departure from Linear Trend6 P < 0.001
 

Relative Risk (Vehicle Control)f Infinite
 

Lower Limit — 3.745
 

Upper Limit — Infinite
 

Weeks to First Observed Tumor — — 34
 00 

-»4 

a

Dosed groups received 12.5 or 25 mg/kg by intraperitoneal injection.
 

^Number of tumor-bearing animals /number of Animals examined at site (percent).
 

G

Beneath the incidence of tumors in a control group is the probability level for the Cochran-


Armitage test when P < 0.05; otherwise, not significant (N.S.) is indicated. Beneath the
 

incidence of tumors in a dosed group is the probability level for the Fisher exact test for
 

the comparison of that dosed group with the vehicle-control group when P < 0.05; otherwise,
 

not significant (N.S.) is indicated.
 

^A negative trend (N) indicates a lower incidence in a dosed group than in a control group.
 

e

The probability level for departure from linear trend is given when P < 0.05 for any comparison.
 

95% confidence interval of the relative risk between each dosed group and the specified
 

control group.
 

Review of the Bioassay of Phenoxybenzamine Hydrochloride*
 

for Carcinogenicity
 

by the Data Evaluation/Risk Assessment Subgroup of the
 

Clearinghouse oh Environmental Carcinogens
 

March 7, 1978
 

The Clearinghouse on Environmental Carcinogens was
 

established in May, 1976, in compliance with DHEW Committee
 

Regulations and the Provisions of the Federal Advisory
 

Committee Act. The purpose of the Clearinghouse is to
 

advise the Director of the National Cancer Institute (NCI)
 

on its bioassay program to identify and to evaluate chemical
 

carcinogens in the environment to which humans may be
 

exposed. The members of the Clearinghouse have been drawn
 

from academia, industry, organized labor, public interest
 

groups, State health officials, and quasi-public health and
 

research organizations. Members have been selected on the
 

basis of their experience in carcinogenesis or related fields
 

and, collectively, provide expertise In chemistry, biochemistry,
 biostatistlcs, toxicology, pathology, and epidemiology.
 Representatives of various Governmental agencies participate
 

as ad hoc members. The Data Evaluation/Risk Assessment Subgroup
 

of the Clearinghouse is charged with the responsibility of
 

providing a peer review of reports prepared on NCI-sponsored
 

bioassays of chemicals studied for carcinogenicity. It is in
 

this context that the below critique is given on the bioassay
 

of Phenoxybenzamine Hydrochloride for carcinogenicity.
 

The primary reviewer agreed with the conclusion that
 

Phenoxybenzamine Hydrochloride produced sarcomas in rats
 

and mice upon interperitoneal injection. Although other
 

tumors were found among treated animals that were not
 

observed in controls, none occurred in statistically signif­ icant numbers. He pointed out the bone marrow atrophy in
 

both controls and treated animals. He also noted that the
 

increased incidence of lung tumors, reported by Stoner et.
 al. in the Strain A mouse system, was in the "mid-zone" and
 

Is really equivalent to a negative. The primary reviewer
 

said that the results did not indicate that Phenoxybenzamine
 

Hydrochloride should be discontinued for the treatment of
 

hypertensive crises, especially since the drug is administered
 

intravenously in humans.
 

The secondary reviewer agreed with the conclusion given
 

in the report. He pointed out the change in vehicle which
 

occurred during the course of the chronic study. Given the
 

usefulness of the drug, he said that it probably should
 

continue to be used. on
 
The primary reviewer moved that the report on the bioassay
 

of Phenoxybenzamine Hydrochloride be accepted as written. The
 

motion was seconded and approved unanimously.
 

Members present were
 

Gerald N. Wogan (Chairman), Massachusetts Institute of
 

Technology
 

Arnold L. Brown, Mayo Clinic
 

Lawrence Garfinkel, American Cancer Society
 

E. Cuyler Hammond, American Cancer Society
 

Joseph Highland, Environmental Defense Fund
 

Henry Pitot, University of Wisconsin Medical Center
 

George Roush, Jr., Monsanto Company
 

Sheldon Samuels, Industrial Union Department, AFL-CIO
 

Michael Shimkin, University of California at San Diego
 

John Weisburger, American Health Foundation
 

Sidney Wolfe, Health Research Group
 

Subsequent to this review, changes may have been made
 

in the bioassay report either as a result of the review
 

or other reasons. Thus, certain comments and criticisms
 

reflected in the review may no longer be appropriate.
 

90 

OU.S. GOVERNMENT PRINTING OFFICE: 1978 260-899/3127 1-3 

DHEW Publication No. (NIH) 78-1322