Guidance for Industry
Carcinogenicity Study
Protocol Submissions
U.S. Department of Health and Human Services
Food and Drug Administration
Center for Drug Evaluation and Research (CDER)
May 2002
PharmacologyToxicology Guidance for Industry
Carcinogenicity Study
Protocol Submissions
Additional copies are available from:
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(Tel) 301-827-4573
(Internet)  http://www.fda.gov/cder/guidance/index.htm
U.S. Department of Health and Human Services
Food and Drug Administration
Center for Drug Evaluation and Research (CDER)
May 2002
PharmacologyToxicology TABLE OF CONTENTS
I. INTRODUCTION.................................................................................................................1
II. BACKGROUND...................................................................................................................1
III. GUIDANCE ON PROTOCOL SUBMISSIONS................................................................2
A. Information Important to Facilitate Protocol Review...........................................................3
B. The Resubmission of Previously Submitted Reports.............................................................4
C. Use of  Body Weight Gain Decrements in a Rangefinding Study in Establishing the Top
Dose for a Carcinogenicity Study..........................................................................................4
D. The Selection of Doses for Rangefinding Experiments..........................................................4
E. Presentation of Data from Rangefinding or Other Toxicity Studies......................................5
F. Use of the Limit Dose............................................................................................................5
i 1
Guidance for Industry
Carcinogenicity Study Protocol Submissions
This guidance represents the Food and Drug Administration's (FDA's) current thinking on this topic.  It
does not create or confer any rights for or on any person and does not operate to bind FDA or the
public.  An alternative approach may be used if such approach satisfies the requirements of the
applicable statutes and regulations.
I. INTRODUCTION
This guidance is intended to inform sponsors of the types of information the Center for Drug
Evaluation and Research (CDER) relies on when evaluating protocols for animal carcinogenicity
studies.
II. BACKGROUND
The Prescription Drug User Fee Act of 1992 (PDUFA) was reauthorized in the Food and Drug
Administration Modernization Action of 1997.  In conjunction with the reauthorization of
PDUFA, FDA agreed to specific performance goals (PDUFA goals) for activities associated with
the development and review of products in human drug applications.2  The PDUFA goals are
summarized in PDUFA Reauthorization Performance Goals and Procedures, an enclosure to a
letter dated November 12, 1997, from the Secretary of Health and Human Services, Donna E.
Shalala, to Senator James M. Jeffords.
The PDUFA goals related to special protocol assessment and agreement provide that, upon
request, FDA will evaluate within 45 calendar days certain protocols and issues relating to the
protocols to assess whether or not they are adequate to meet scientific and regulatory
requirements identified by the sponsor.  Protocols for animal carcinogenicity studies are eligible
for this special protocol assessment.3   This guidance is intended to facilitate the Agencys
review of protocols for animal carcinogenicity studies by informing sponsors of the types of
information the Agency relies on during its evaluation of such protocols.
                                                
1 This guidance has been prepared by the Office of Review Management in the Center for Drug Evaluation and
Research (CDER) at the Food and Drug Administration (FDA).
2 The term human drug application is defined in section 735(1) of the Federal Food, Drug, and Cosmetic Act.
3 The Agency published a draft guidance on Special Protocol Assessment in February 2000.  Once finalized, that
guidance will reflect the Agency's current views on submitting information to CDER for special protocol
assessment.
1 Although protocol submissions not supplying all of the information described in this document
can be evaluated by CDER, an incomplete package may make it extremely difficult for the
Agency to reach agreement on a protocol or recommend alternative study designs.  In situations
where insufficient information is provided, the sponsor may be told that the committee was
unable to concur with the proposed protocol.
Prior to designing carcinogenicity studies, sponsors should review the ICH guidances S1C Dose
Selection for Carcinogenicity Studies of Pharmaceuticals (March 1995) and S1C(R) Guidance
on Dose Selection for Carcinogenicity Studies of Pharmaceuticals:  Addendum on a Limit Dose
and Related Notes (December 1997).  The highest dose to be included in a carcinogenicity study
should be based on one of the ICH endpoints.4  Sponsors also should review S1B Testing for
Carcinogenicity of Pharmaceuticals (February 1998), which provides guidance on species
selection and alternative approaches to the standard 2-species/2-year testing paradigm.
III. GUIDANCE ON PROTOCOL SUBMISSIONS
In CDER, primary responsibility for the review of protocols for animal carcinogenicity studies
lies with the review division.  The review division consults with CDERs Carcinogenicity
Assessment Committee (CAC) or CDER's Executive Carcinogenicity Assessment Committee
(Exec CAC).  These committees provide an oversight review of the study protocols and provide
written comments on the appropriateness of the protocol from CDERs perspective on
approaches to testing, including the study type, doses employed, and other design issues.
To facilitate the review process, at least 30 days prior to submission of the study protocol,
sponsors should notify the Agency in writing that a carcinogenicity protocol will be arriving.
The carcinogenicity protocol and questions regarding the protocol should be submitted in
sufficient time prior to the anticipated initiation of the study to allow for meaningful discourse
with the Agency and resolution of any issues before study initiation.  Submission should be made
to the appropriate review division in CDER.  The submission should be clearly marked in bold
black letters as a REQUEST FOR SPECIAL PROTOCOL ASSESSMENT.  It also should be
clearly marked as a carcinogenicity study protocol 5
. 
PDUFA goals for special protocol assessment do not apply to requests for assessment of ongoing
carcinogenicity studies. CDER intends to review the protocols for these ongoing studies and to
provide a response to such review requests in a timely manner.
                                                
4 Toxicity, Dose-Limiting PD Effects, Exposures 25 times Human AUC, Saturation of Absorption, Maximum
Feasible Dose (MFD), or Limit Dose.
5 The Agency published a draft guidance on Special Protocol Assessment in February 2000.  Once finalized, that
guidance will reflect the Agency's current views on submitting information to CDER for special protocol
assessment.
2 A.  Information Important to Facilitate Protocol Review
The type of information important for evaluating carcinogenicity protocols will vary with
the proposed study design and test approach (see the table at the end of this guidance).
Not all of the information discussed below is essential for all study designs or dose
selection endpoints.  In all cases, however, the comprehensive submission of the
following information will facilitate the Agency's protocol review.  As explained in ICH
guidance S1C, sponsors should include the basis for dose selection.
1.  A toxicology study report should be included reflecting the same conditions as
proposed for the carcinogenicity study (same mode of administration, same diet,
same rodent strain).  Unaudited draft reports (containing summary tables and
individual animal data) can be submitted.6  The usual duration of this type of
study is 90 days if it is intended to support dose selection for a standard 2-year
carcinogen bioassay.7  Studies of shorter duration may be appropriate for
alternative bioassays (see the recommendations in ICH S1B and S1C).
2.  Metabolic profiles should be provided for the drug in humans and in the species
employed for assessment of carcinogenic potential.  In cases where in vivo data
are unavailable, in vitro data can be used (see the recommendations in ICH S1C).8
3.  Toxicokinetic data should be provided that are sufficient to estimate steady state
AUC  for the parent drug and each major human metabolite at doses employed
(0-24)
in the rangefinding study.  For determining the appropriateness of using
AUC/limit dose approaches, major metabolites are defined as metabolites that, if
excluded from the analysis, significantly change the comparison ratios between
species.  Data (point estimates as well as individual animal values) should be
reported separately for males and females from the same strain as proposed for
the bioassay.9
4.  Exposure (steady state AUC ) data should be provided for the parent drug and
(0-24)
for the major metabolites from clinical trials conducted at the maximum
                                                
6 See the guidance for industry on Content and Format of Investigational New Drug Applications (INDs) for
Phase 1 Studies of Drugs, Including Well-Characterized, Therapeutic, Biotechnology-derived Products (November
1995).
7 Irrespective of method of dosage qualification, a rangefinding study is important to ensure that doses selected are
likely to be tolerated in the carcinogen bioassay.  The need for a rangefinding study may be obviated by the
existence of other information, such as chronic toxicity data, depending on the design and outcome of the chronic
toxicity studies.
8 Regardless of endpoint used for dose selection, this information is used to ensure that the animal species proposed
for testing is a reasonable surrogate for assessing carcinogenic potential in humans.
9 This information is used to justify selected doses on the basis of multiple of human systemic exposure, saturation
of absorption, or limit dose endpoints.  Irrespective of dose-selection endpoint, this information is used in the
selection of the appropriate dose spread and can be used for product labeling.
3 recommended human dose (MRHD) or other appropriate human reference dose if
the MRHD exposure data are unavailable.10   Where pharmacokinetics differ
significantly between genders, data from males and females should be reported
separately, as a gender difference can modify the study approach and conclusions.
It is our experience that gender differences occur rarely.
5. Plasma protein binding data should be provided for the parent drug and the major
human metabolites (to the extent feasible) in the rodent test species over the range
of concentrations encountered in the dose-rangefinding experiment and in humans
at concentrations encountered in clinical trials conducted at the reference dose.
6. A summary of the investigations into the genotoxic potential of the drug and its
major human metabolites should be included.11  Positive genotoxicity results for
parent or metabolites can preclude use of AUC ratios, limit dose (ICH Guidances
S1C and S1C(R)), and influence the choice of alternatives assays.
B.  The Resubmission of Previously Submitted Reports
When a sponsor relies on reports critical to the chosen dose-selection endpoint that were
previously submitted to the Agency, CDER encourages sponsors to resubmit the actual
reports or, at least, summaries of the reports.  Previously submitted reports can be
referenced by submission number and correspondence date (rather than being
resubmitted), but submitting the actual reports or their summaries will speed the Agency's
review of the carcinogenicity protocol.
C. Use of  Body Weight Gain Decrements in a Rangefinding Study in
Establishing the Top Dose for a Carcinogenicity Study
In a dietary administration study, when body weight gain decrements are accompanied by
reductions in food consumption and such body weight effects are the only basis for
dosage selection, it is important for the sponsor to document that the reduced
consumption is not a consequence of a palatability problem.  This documentation is
important because if the drug is not palatable, higher doses might be tolerated with
another mode of administration (e.g., gavage), and the proposed dietary mode of
administering doses may not be appropriate.
D.  The Selection of Doses for Rangefinding Experiments
The chosen doses should clearly elicit effects that can be used as endpoints as
recommended in the ICH guidances.  The doses selected should include a dose that is
                                                
10 In some cases the MRHD is unknown at the time of carcinogenicity protocol initiation, and an alternative
reference dose can be used to determine human exposure.  An example of an acceptable alternative approach could
be to determine exposure at a human dose eliciting toxicity such that higher doses would not be acceptable for the
indication.  The basis for the choice of the human dose used in the comparison should be provided.
11 This information is used to determine the appropriateness of using the multiple of human systemic exposure or
limit dose endpoints in accordance with ICH guidances.
4 without significant toxicity.  It is generally unnecessary to include the maximum feasible
dose in the design of the rangefinding experiments when it is known that doses lower
than the maximum feasible dose, when administered by the same mode of administration
in other toxicity studies, are clearly not tolerated or exceed other acceptable dose
selection endpoints.  In the absence of such information from other studies, it may be
prudent to include the maximum feasible dose in the design of the rangefinding
experiments.
E.  Presentation of Data from Rangefinding or Other Toxicity Studies
Results of toxicity studies submitted in support of dose-selection should be presented in a
tabular format and reported separately for males and females.  Histopathology tables that
provide information on both incidence and severity of findings are important to allow
adequate dose selection.  Clinical pathology tables should include the group mean value
and standard deviation for each parameter reported.  Graphical illustration of changes in
body weight over the course of the study is encouraged.
F.  Use of the Limit Dose
The ICH guidance S1C(R) supports the use of a limit dose (1500 mg/kg/day) when
certain criteria are met.  One of those criteria is that it can be ensured that the rodent
exposure to the drug and metabolites at 1500 mg/kg/day exceeds systemic human
exposure (AUC) at the MRHD by greater than an order of magnitude.  For the purposes
of this guidance, CDER considers this has been demonstrated if the lower 95 percent
confidence limit for AUC in the rodent is at least 10 times the AUC in humans at the
MRHD.
5 Tabular Summary of Types of Data Useful for Evaluation of Carcinogenicity Bioassay Protocols
Types of Data Useful for Evaluation of Carcinogenicity Bioassay Protocols
 Dose Selection      Human and    
 General Toxicity  Genotoxicity  Animal  Animal AUC a.  Human AUC a.
Endpoint
Information Metabolism (Unbound) (Unbound)
 
         
 Toxicity  (cid:214)         A  m  ---  ---
 (MTD)
 
 Multiple of        
 Huma (n2 5E Xxp)osure  (cid:214)         (cid:214)  (cid:214)  (cid:214)  (cid:214)
 
 Saturation of        
Absorption  (cid:214)         A  m  (cid:214)  ---
 of Drug Related
Substances
         
 MFD  (cid:214)         A  m  ---  ---
 
         
 Limit Dose  (cid:214)         (cid:214)  (cid:214)  (cid:214)  (cid:214)
 
     
 Pharmacodynamic  (cid:214)         A  m                   ---                ---
Effects
 
 
a.  AUC for unbound drug is crucial where unbound fraction of drug is greater in humans than animals, but can be used in other
circumstances.
(cid:214)    Important to support this dose selection endpoint for alternative and standard model
A  Important for selection of alternative model for these dose selection endpoints
m  Information used primarily to support test model (species and strain) for these endpoints
--- Not applicable to this endpoint
6