[Federal Register Volume 62, Number 222 (Tuesday, November 18, 1997)]
[Notices]
[Pages 61515-61519]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-30274]
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DEPARTMENT OF HEALTH AND HUMAN SERVICES
Food and Drug Administration
[Docket No. 97D-0113]
International Conference on Harmonisation; Guidance on
Preclinical Safety Evaluation of Biotechnology-Derived Pharmaceuticals;
Availability
AGENCY: Food and Drug Administration, HHS.
ACTION: Notice.
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SUMMARY: The Food and Drug Administration (FDA) is publishing a
guidance entitled ``S6 Preclinical Safety Evaluation of Biotechnology-
Derived Pharmaceuticals.'' The guidance was prepared under the auspices
of the International Conference on Harmonisation of Technical
Requirements for Registration of Pharmaceuticals for Human Use (ICH).
The guidance is intended to provide general principles for designing
scientifically acceptable preclinical safety evaluation programs for
biopharmaceuticals.
DATES: Effective November 18, 1997. Submit written comments at any
time.
ADDRESSES: Submit written comments on the guidance to the Dockets
Management Branch (HFA-305), Food and Drug Administration, 12420
Parklawn Dr., rm. 1-23, Rockville, MD 20857. Copies of the guidance are
available from the Drug Information Branch (HFD-210), Center for Drug
Evaluation and Research, Food and Drug Administration, 5600 Fishers
Lane, Rockville, MD 20857, 301-827-4573. Single copies of the draft
guidance may be obtained by mail from the Office of Communication,
Training and Manufacturers Assistance (HFM-40), Center for Biologics
Evaluation and Research (CBER), or by calling the CBER Voice
Information System at 1-800-835-4709 or 301-827-1800. Copies may be
obtained from CBER's Fax Information System at 1-888-CBER-FAX or 301-
827-3844.
FOR FURTHER INFORMATION CONTACT:
Regarding the guidance: Joy A. Cavagnaro, Center for Biologics
Evaluation and Research (HFM-5), Food and Drug Administration, 1401
Rockville Pike, Rockville, MD 20852, 301-827-0379.
Regarding the ICH: Janet J. Showalter, Office of Health Affairs
(HFY-20), Food and Drug Administration, 5600 Fishers Lane, Rockville,
MD 20857, 301-827-0864.
SUPPLEMENTARY INFORMATION: In recent years, many important initiatives
have been undertaken by regulatory authorities and industry
associations to promote international harmonization of regulatory
requirements. FDA has participated in many meetings designed to enhance
harmonization and is committed to seeking scientifically based
harmonized technical procedures for pharmaceutical development. One of
the goals of harmonization is to identify and then reduce differences
in technical requirements for drug development among regulatory
agencies.
ICH was organized to provide an opportunity for tripartite
harmonization initiatives to be developed with input from both
regulatory and industry representatives. FDA also seeks input from
consumer representatives and others. ICH is concerned with
harmonization of technical requirements for the registration of
pharmaceutical products among three regions: The European Union, Japan,
and the United States. The six ICH sponsors are the European
Commission, the European Federation of Pharmaceutical Industries
Associations, the Japanese Ministry of Health and Welfare, the Japanese
Pharmaceutical Manufacturers Association, the Centers for Drug
Evaluation and Research and Biologics Evaluation and Research, FDA, and
the Pharmaceutical Research and Manufacturers of America. The ICH
Secretariat, which coordinates the preparation of documentation, is
provided by the International Federation of Pharmaceutical
Manufacturers Associations (IFPMA).
The ICH Steering Committee includes representatives from each of
the ICH sponsors and the IFPMA, as well as observers from the World
Health Organization, the Canadian Health Protection Branch, and the
European Free Trade Area.
In the Federal Register of April 4, 1997 (62 FR 16438), FDA
published a draft tripartite guideline entitled ``Preclinical Testing
of Biotechnology-Derived Pharmaceuticals'' (S6). The notice gave
interested persons an opportunity to submit comments by June 3, 1997.
After consideration of the comments received and revisions to the
guidance, a final draft of the guidance was submitted to the ICH
Steering Committee and endorsed by the three participating regulatory
agencies on July 16, 1997.
In accordance with FDA's Good Guidance Practices (62 FR 8961,
February 27, 1997), this document has been designated a guidance,
rather than a guideline.
The guidance recommends a basic framework for the preclinical
safety evaluation of biotechnology-derived pharmaceuticals. Adherence
to the principles presented in the guidance will allow for improvement
in the quality and consistency of preclinical safety data supporting
the development of biopharmaceuticals.
This guidance represents the agency's current thinking on
preclinical safety evaluation of biotechnology-derived pharmaceuticals.
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
statute, regulations, or both.
As with all of FDA's guidances, the public is encouraged to submit
written comments with new data or other new information pertinent to
this guidance. The comments in the docket will be periodically
reviewed, and, where appropriate, the guidance will be amended. The
public will be notified of any such amendments through a notice in the
Federal Register.
[[Page 61516]]
Interested persons may, at any time, submit written comments on the
guidance to the Dockets Management Branch (address above). Two copies
of any comments are to be submitted, except that individuals may submit
one copy. Comments are to be identified with the docket number found in
brackets in the heading of this document. The guidance and received
comments may be seen in the office above between 9 a.m. and 4 p.m.,
Monday through Friday. An electronic version of this guidance is
available on the Internet at ``http://www.fda.gov/cder/guidance.htm''
or at CBER's World Wide Web site at ``http://www.fda.gov/cber/
publications.htm''.
The text of the guidance follows:
S6 Preclinical Safety Evaluation of Biotechnology-Derived
Pharmaceuticals \1\
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\1\ This guidance represents the agency's current thinking on
preclinical safety evaluation of biotechnology-derived
pharmaceuticals. 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 of such approach satisfies the
requirements of the applicable statute, regulations, or both.
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1. Introduction
1.1. Background
Biotechnology-derived pharmaceuticals (biopharmaceuticals) were
initially developed in the early 1980's. The first marketing
authorizations were granted later in the decade. Several guidelines
and points-to-consider documents have been issued by various
regulatory agencies regarding safety assessment of these products.
Review of such documents, which are available from regulatory
authorities, may provide useful background in developing new
biopharmaceuticals.
Considerable experience has now been gathered with submission of
applications for biopharmaceuticals. Critical review of this
experience has been the basis for development of this guidance,
which is intended to provide general principles for designing
scientifically acceptable preclinical safety evaluation programs.
1.2 Objectives
Regulatory standards for biotechnology-derived pharmaceuticals
have generally been comparable among the European Union, Japan, and
the United States. All three regions have adopted a flexible, case-
by-case, science-based approach to preclinical safety evaluation
needed to support clinical development and marketing authorization.
In this rapidly evolving scientific area, there is a need for common
understanding and continuing dialogue among the regions.
The primary goals of preclinical safety evaluation are: (1) To
identify an initial safe dose and subsequent dose escalation schemes
in humans; (2) to identify potential target organs for toxicity and
for the study of whether such toxicity is reversible; and (3) to
identify safety parameters for clinical monitoring. Adherence to the
principles presented in this document should improve the quality and
consistency of the preclinical safety data supporting the
development of biopharmaceuticals.
1.3 Scope
This guidance is intended primarily to recommend a basic
framework for the preclinical safety evaluation of biotechnology-
derived pharmaceuticals. It applies to products derived from
characterized cells through the use of a variety of expression
systems including bacteria, yeast, insect, plant, and mammalian
cells. The intended indications may include in vivo diagnostic,
therapeutic, or prophylactic uses. The active substances include
proteins and peptides, their derivatives, and products of which they
are components; they could be derived from cell cultures or produced
using recombinant deoxyrebonucleic acid (DNA) technology, including
production by transgenic plants and animals. Examples include but
are not limited to: Cytokines, plasminogen activators, recombinant
plasma factors, growth factors, fusion proteins, enzymes, receptors,
hormones, and monoclonal antibodies.
The principles outlined in this guidance may also be applicable
to recombinant DNA protein vaccines, chemically synthesized
peptides, plasma derived products, endogenous proteins extracted
from human tissue, and oligonucleotide drugs.
This document does not cover antibiotics, allergenic extracts,
heparin, vitamins, cellular blood components, conventional bacterial
or viral vaccines, DNA vaccines, or cellular and gene therapies.
2. Specification of the Test Material
Safety concerns may arise from the presence of impurities or
contaminants. It is preferable to rely on purification processes to
remove impurities and contaminants rather than to establish a
preclinical testing program for their qualification. In all cases,
the product should be sufficiently characterized to allow an
appropriate design of preclinical safety studies.
There are potential risks associated with host cell contaminants
derived from bacteria, yeast, insect, plants, and mammalian cells.
The presence of cellular host contaminants can result in allergic
reactions and other immunopathological effects. The adverse effects
associated with nucleic acid contaminants are theoretical but
include potential integration into the host genome. For products
derived from insect, plant, and mammalian cells, or transgenic
plants and animals, there may be an additional risk of viral
infections.
In general, the product that is used in the definitive
pharmacology and toxicology studies should be comparable to the
product proposed for the initial clinical studies. However, it is
appreciated that during the course of development programs, changes
normally occur in the manufacturing process in order to improve
product quality and yields. The potential impact of such changes for
extrapolation of the animal findings to humans should be considered.
The comparability of the test material during a development
program should be demonstrated when a new or modified manufacturing
process is developed or other significant changes in the product or
formulation are made in an ongoing development program.
Comparability can be evaluated on the basis of biochemical and
biological characterization (i.e., identity, purity, stability, and
potency). In some cases, additional studies may be needed (i.e.,
pharmacokinetics, pharmacodynamics and/or safety). The scientific
rationale for the approach taken should be provided.
3. Preclinical Safety Testing
3.1 General Principles
The objectives of the preclinical safety studies are to define
pharmacological and toxicological effects not only prior to
initiation of human studies but throughout clinical development.
Both in vitro and in vivo studies can contribute to this
characterization. Biopharmaceuticals that are structurally and
pharmacologically comparable to a product for which there is wide
experience in clinical practice may need less extensive toxicity
testing.
Preclinical safety testing should consider: (1) Selection of the
relevant animal species; (2) age; (3) physiological state; (4) the
manner of delivery, including dose, route of administration, and
treatment regimen; and (5) stability of the test material under the
conditions of use.
Toxicity studies are expected to be performed in compliance with
Good Laboratory Practice (GLP); however, it is recognized that some
studies employing specialized test systems, which are often needed
for biopharmaceuticals, may not be able to comply fully with GLP.
Areas of noncompliance should be identified and their significance
evaluated relative to the overall safety assessment. In some cases,
lack of full GLP compliance does not necessarily mean that the data
from these studies cannot be used to support clinical trials and
marketing authorizations.
Conventional approaches to toxicity testing of pharmaceuticals
may not be appropriate for biopharmaceuticals due to the unique and
diverse structural and biological properties of the latter that may
include species specificity, immunogenicity, and unpredicted
pleiotropic activities.
3.2 Biological Activity/Pharmacodynamics
Biological activity may be evaluated using in vitro assays to
determine which effects of the product may be related to clinical
activity. The use of cell lines and/or primary cell cultures can be
useful to examine the direct effects on cellular phenotype and
proliferation. Due to the species specificity of many biotechnology-
derived pharmaceuticals, it is important to select relevant animal
species for toxicity testing. In vitro cell lines derived from
mammalian cells can be used to predict specific aspects of in vivo
activity and to assess quantitatively the relative sensitivity of
various species (including human) to the biopharmaceutical. Such
studies may be designed to determine, for example, receptor
occupancy, receptor affinity, and/or pharmacological effects, and to
assist in the selection of an appropriate animal species for further
in vivo
[[Page 61517]]
pharmacology and toxicology studies. The combined results from in
vitro and in vivo studies assist in the extrapolation of the
findings to humans. In vivo studies to assess pharmacological
activity, including defining mechanism(s) of action, are often used
to support the rationale of the proposed use of the product in
clinical studies.
For monoclonal antibodies, the immunological properties of the
antibody should be described in detail, including its antigenic
specificity, complement binding, and any unintentional reactivity
and/or cytotoxicity towards human tissues distinct from the intended
target. Such cross-reactivity studies should be carried out by
appropriate immunohistochemical procedures using a range of human
tissues.
3.3 Animal Species/Model Selection
The biological activity together with species and/or tissue
specificity of many biotechnology-derived pharmaceuticals often
preclude standard toxicity testing designs in commonly used species
(e.g., rats and dogs). Safety evaluation programs should include the
use of relevant species. A relevant species is one in which the test
material is pharmacologically active due to the expression of the
receptor or an epitope (in the case of monoclonal antibodies). A
variety of techniques (e.g., immunochemical or functional tests) can
be used to identify a relevant species. Knowledge of receptor/
epitope distribution can provide greater understanding of potential
in vivo toxicity.
Relevant animal species for testing of monoclonal antibodies are
those that express the desired epitope and demonstrate a similar
tissue cross-reactivity profile as for human tissues. This would
optimize the ability to evaluate toxicity arising from the binding
to the epitope and any unintentional tissue cross-reactivity. An
animal species that does not express the desired epitope may still
be of some relevance for assessing toxicity if comparable
unintentional tissue cross-reactivity to humans is demonstrated.
Safety evaluation programs should normally include two relevant
species. However, in certain justified cases one relevant species
may suffice (e.g., when only one relevant species can be identified
or where the biological activity of the biopharmaceutical is well
understood). In addition, even where two species may be necessary to
characterize toxicity in short term studies, it may be possible to
justify the use of only one species for subsequent long-term
toxicity studies (e.g., if the toxicity profile in the two species
is comparable in the short term).
Toxicity studies in nonrelevant species may be misleading and
are discouraged. When no relevant species exists, the use of
relevant transgenic animals expressing the human receptor or the use
of homologous proteins should be considered. The information gained
from use of a transgenic animal model expressing the human receptor
is optimized when the interaction of the product and the humanized
receptor has similar physiological consequences to those expected in
humans. While useful information may also be gained from the use of
homologous proteins, it should be noted that the production process,
range of impurities/contaminants, pharmacokinetics, and exact
pharmacological mechanism(s) may differ between the homologous form
and the product intended for clinical use. Where it is not possible
to use transgenic animal models or homologous proteins, it may still
be prudent to assess some aspects of potential toxicity in a limited
toxicity evaluation in a single species, e.g., a repeated dose
toxicity study of < 14="" days="" duration="" that="" includes="" an="" evaluation="" of="" important="" functional="" endpoints="" (e.g.,="" cardiovascular="" and="" respiratory).="" in="" recent="" years,="" there="" has="" been="" much="" progress="" in="" the="" development="" of="" animal="" models="" that="" are="" thought="" to="" be="" similar="" to="" the="" human="" disease.="" these="" animal="" models="" include="" induced="" and="" spontaneous="" models="" of="" disease,="" gene="" knockout(s),="" and="" transgenic="" animals.="" these="" models="" may="" provide="" further="" insight,="" not="" only="" in="" determining="" the="" pharmacological="" action="" of="" the="" product,="" pharmacokinetics,="" and="" dosimetry,="" but="" may="" also="" be="" useful="" in="" the="" determination="" of="" safety="" (e.g.,="" evaluation="" of="" undesirable="" promotion="" of="" disease="" progression).="" in="" certain="" cases,="" studies="" performed="" in="" animal="" models="" of="" disease="" may="" be="" used="" as="" an="" acceptable="" alternative="" to="" toxicity="" studies="" in="" normal="" animals="" (note="" 1).="" the="" scientific="" justification="" for="" the="" use="" of="" these="" animal="" models="" of="" disease="" to="" support="" safety="" should="" be="" provided.="" 3.4="" number/gender="" of="" animals="" the="" number="" of="" animals="" used="" per="" dose="" has="" a="" direct="" bearing="" on="" the="" ability="" to="" detect="" toxicity.="" a="" small="" sample="" size="" may="" lead="" to="" failure="" to="" observe="" toxic="" events="" due="" to="" observed="" frequency="" alone="" regardless="" of="" severity.="" the="" limitations="" that="" are="" imposed="" by="" sample="" size,="" as="" often="" is="" the="" case="" for="" nonhuman="" primate="" studies,="" may="" be="" in="" part="" compensated="" by="" increasing="" the="" frequency="" and="" duration="" of="" monitoring.="" both="" genders="" should="" generally="" be="" used="" or="" justification="" given="" for="" specific="" omissions.="" 3.5="" administration/dose="" selection="" the="" route="" and="" frequency="" of="" administration="" should="" be="" as="" close="" as="" possible="" to="" that="" proposed="" for="" clinical="" use.="" consideration="" should="" be="" given="" to="" pharmacokinetics="" and="" bioavailability="" of="" the="" product="" in="" the="" species="" being="" used="" and="" to="" the="" volume="" which="" can="" be="" safely="" and="" humanely="" administered="" to="" the="" test="" animals.="" for="" example,="" the="" frequency="" of="" administration="" in="" laboratory="" animals="" may="" be="" increased="" compared="" to="" the="" proposed="" schedule="" for="" the="" human="" clinical="" studies="" in="" order="" to="" compensate="" for="" faster="" clearance="" rates="" or="" low="" solubility="" of="" the="" active="" ingredient.="" in="" these="" cases,="" the="" level="" of="" exposure="" of="" the="" test="" animal="" relative="" to="" the="" clinical="" exposure="" should="" be="" defined.="" consideration="" should="" also="" be="" given="" to="" the="" effects="" of="" volume,="" concentration,="" formulation,="" and="" site="" of="" administration.="" the="" use="" of="" routes="" of="" administration="" other="" than="" those="" used="" clinically="" may="" be="" acceptable="" if="" the="" route="" must="" be="" modified="" due="" to="" limited="" bioavailability,="" limitations="" due="" to="" the="" route="" of="" administration,="" or="" to="" size/physiology="" of="" the="" animal="" species.="" dosage="" levels="" should="" be="" selected="" to="" provide="" information="" on="" a="" dose-response="" relationship,="" including="" a="" toxic="" dose="" and="" a="" no="" observed="" adverse="" effect="" level="" (noael).="" for="" some="" classes="" of="" products="" with="" little="" to="" no="" toxicity,="" it="" may="" not="" be="" possible="" to="" define="" a="" specific="" maximum="" dose.="" in="" these="" cases,="" a="" scientific="" justification="" of="" the="" rationale="" for="" the="" dose="" selection="" and="" projected="" multiples="" of="" human="" exposure="" should="" be="" provided.="" to="" justify="" high="" dose="" selection,="" consideration="" should="" be="" given="" to="" the="" expected="" pharmacological/="" physiological="" effects,="" availability="" of="" suitable="" test="" material,="" and="" the="" intended="" clinical="" use.="" where="" a="" product="" has="" a="" lower="" affinity="" to="" or="" potency="" in="" the="" cells="" of="" the="" selected="" species="" than="" in="" human="" cells,="" testing="" of="" higher="" doses="" may="" be="" important.="" the="" multiples="" of="" the="" human="" dose="" that="" are="" needed="" to="" determine="" adequate="" safety="" margins="" may="" vary="" with="" each="" class="" of="" biotechnology-derived="" pharmaceutical="" and="" its="" clinical="" indication(s).="" 3.6="" immunogenicity="" many="" biotechnology-derived="" pharmaceuticals="" intended="" for="" humans="" are="" immunogenic="" in="" animals.="" therefore,="" measurement="" of="" antibodies="" associated="" with="" administration="" of="" these="" types="" of="" products="" should="" be="" performed="" when="" conducting="" repeated="" dose="" toxicity="" studies="" in="" order="" to="" aid="" in="" the="" interpretation="" of="" these="" studies.="" antibody="" responses="" should="" be="" characterized="" (e.g.,="" titer,="" number="" of="" responding="" animals,="" neutralizing="" or="" non-neutralizing)="" and="" their="" appearance="" should="" be="" correlated="" with="" any="" pharmacological="" and/or="" toxicological="" changes.="" specifically,="" the="" effects="" of="" antibody="" formation="" on="" pharmacokinetic/="" pharmacodynamic="" parameters,="" incidence="" and/or="" severity="" of="" adverse="" effects,="" complement="" activation,="" or="" the="" emergence="" of="" new="" toxic="" effects="" should="" be="" considered="" when="" interpreting="" the="" data.="" attention="" should="" also="" be="" paid="" to="" the="" evaluation="" of="" possible="" pathological="" changes="" related="" to="" immune="" complex="" formation="" and="" deposition.="" the="" detection="" of="" antibodies="" should="" not="" be="" the="" sole="" criterion="" for="" the="" early="" termination="" of="" a="" preclinical="" safety="" study="" or="" modification="" in="" the="" duration="" of="" the="" study="" design="" unless="" the="" immune="" response="" neutralizes="" the="" pharmacological="" and/or="" toxicological="" effects="" of="" the="" biopharmaceutical="" in="" a="" large="" proportion="" of="" the="" animals.="" in="" most="" cases,="" the="" immune="" response="" to="" biopharmaceuticals="" is="" variable,="" like="" that="" observed="" in="" humans.="" if="" the="" interpretation="" of="" the="" data="" from="" the="" safety="" study="" is="" not="" compromised="" by="" these="" issues,="" then="" no="" special="" significance="" should="" be="" ascribed="" to="" the="" antibody="" response.="" the="" induction="" of="" antibody="" formation="" in="" animals="" is="" not="" predictive="" of="" a="" potential="" for="" antibody="" formation="" in="" humans.="" humans="" may="" develop="" serum="" antibodies="" against="" humanized="" proteins,="" and="" frequently="" the="" therapeutic="" response="" persists="" in="" their="" presence.="" the="" occurrence="" of="" severe="" anaphylactic="" responses="" to="" recombinant="" proteins="" is="" rare="" in="" humans.="" in="" this="" regard,="" the="" results="" of="" guinea="" pig="" anaphylaxis="" tests,="" which="" are="" generally="" positive="" for="" protein="" products,="" are="" not="" predictive="" for="" reactions="" in="" humans;="" therefore,="" such="" studies="" are="" considered="" of="" little="" value="" for="" the="" routine="" evaluation="" of="" these="" types="" of="" products.="" [[page="" 61518]]="" 4.="" specific="" considerations="" 4.1="" safety="" pharmacology="" it="" is="" important="" to="" investigate="" the="" potential="" for="" undesirable="" pharmacological="" activity="" in="" appropriate="" animal="" models="" and,="" where="" necessary,="" to="" incorporate="" particular="" monitoring="" for="" these="" activities="" in="" the="" toxicity="" studies="" and/or="" clinical="" studies.="" safety="" pharmacology="" studies="" measure="" functional="" indices="" of="" potential="" toxicity.="" these="" functional="" indices="" may="" be="" investigated="" in="" separate="" studies="" or="" incorporated="" in="" the="" design="" of="" toxicity="" studies.="" the="" aim="" of="" the="" safety="" pharmacology="" studies="" should="" be="" to="" reveal="" any="" functional="" effects="" on="" the="" major="" physiological="" systems="" (e.g.,="" cardiovascular,="" respiratory,="" renal,="" and="" central="" nervous="" systems).="" investigations="" may="" also="" include="" the="" use="" of="" isolated="" organs="" or="" other="" test="" systems="" not="" involving="" intact="" animals.="" all="" of="" these="" studies="" may="" allow="" for="" a="" mechanistically-based="" explanation="" of="" specific="" organ="" toxicities,="" which="" should="" be="" considered="" carefully="" with="" respect="" to="" human="" use="" and="" indication(s).="" 4.2="" exposure="" assessment="" 4.2.1="" pharmacokinetics="" and="" toxicokinetics="" it="" is="" difficult="" to="" establish="" uniform="" guidances="" for="" pharmacokinetic="" studies="" for="" biotechnology-derived="" pharmaceuticals.="" single="" and="" multiple="" dose="" pharmacokinetics,="" toxicokinetics,="" and="" tissue="" distribution="" studies="" in="" relevant="" species="" are="" useful;="" however,="" routine="" studies="" that="" attempt="" to="" assess="" mass="" balance="" are="" not="" useful.="" differences="" in="" pharmacokinetics="" among="" animal="" species="" may="" have="" a="" significant="" impact="" on="" the="" predictiveness="" of="" animal="" studies="" or="" on="" the="" assessment="" of="" dose-response="" relationships="" in="" toxicity="" studies.="" alterations="" in="" the="" pharmacokinetic="" profile="" due="" to="" immune-mediated="" clearance="" mechanisms="" may="" affect="" the="" kinetic="" profiles="" and="" the="" interpretation="" of="" the="" toxicity="" data.="" for="" some="" products,="" there="" may="" also="" be="" inherent,="" significant="" delays="" in="" the="" expression="" of="" pharmacodynamic="" effects="" relative="" to="" the="" pharmacokinetic="" profile="" (e.g.,="" cytokines)="" or="" there="" may="" be="" prolonged="" expression="" of="" pharmacodynamic="" effects="" relative="" to="" plasma="" levels.="" pharmacokinetic="" studies="" should,="" whenever="" possible,="" utilize="" preparations="" that="" are="" representative="" of="" those="" intended="" for="" toxicity="" testing="" and="" clinical="" use="" and="" employ="" a="" route="" of="" administration="" that="" is="" relevant="" to="" the="" anticipated="" clinical="" studies.="" patterns="" of="" absorption="" may="" be="" influenced="" by="" formulation,="" concentration,="" site,="" and/or="" volume.="" whenever="" possible,="" systemic="" exposure="" should="" be="" monitored="" during="" the="" toxicity="" studies.="" when="" using="" radiolabeled="" proteins,="" it="" is="" important="" to="" show="" that="" the="" radiolabeled="" test="" material="" maintains="" activity="" and="" biological="" properties="" equivalent="" to="" that="" of="" the="" unlabeled="" material.="" tissue="" concentrations="" of="" radioactivity="" and/or="" autoradiography="" data="" using="" radiolabeled="" proteins="" may="" be="" difficult="" to="" interpret="" due="" to="" rapid="" in="" vivo="" metabolism="" or="" unstable="" radiolabeled="" linkage.="" care="" should="" be="" taken="" in="" the="" interpretation="" of="" studies="" using="" radioactive="" tracers="" incorporated="" into="" specific="" amino="" acids="" because="" of="" recycling="" of="" amino="" acids="" into="" nondrug="" related="" proteins/peptides.="" some="" information="" on="" absorption,="" disposition,="" and="" clearance="" in="" relevant="" animal="" models="" should="" be="" available="" prior="" to="" clinical="" studies="" in="" order="" to="" predict="" margins="" of="" safety="" based="" upon="" exposure="" and="" dose.="" 4.2.2="" assays="" the="" use="" of="" one="" or="" more="" assay="" methods="" should="" be="" addressed="" on="" a="" case-by-case="" basis="" and="" the="" scientific="" rationale="" should="" be="" provided.="" one="" validated="" method="" is="" usually="" considered="" sufficient.="" for="" example,="" quantitation="" of="" tca-precipitable="" radioactivity="" following="" administration="" of="" a="" radiolabeled="" protein="" may="" provide="" adequate="" information,="" but="" a="" specific="" assay="" for="" the="" analyte="" is="" preferred.="" ideally,="" the="" assay="" methods="" should="" be="" the="" same="" for="" animals="" and="" humans.="" the="" possible="" influence="" of="" plasma="" binding="" proteins="" and/or="" antibodies="" in="" plasma/serum="" on="" the="" assay="" performance="" should="" be="" determined.="" 4.2.3="" metabolism="" the="" expected="" consequence="" of="" metabolism="" of="" biotechnology-derived="" pharmaceuticals="" is="" the="" degradation="" to="" small="" peptides="" and="" individual="" amino="" acids.="" therefore,="" the="" metabolic="" pathways="" are="" generally="" understood.="" classical="" biotransformation="" studies="" as="" performed="" for="" pharmaceuticals="" are="" not="" needed.="" understanding="" the="" behavior="" of="" the="" biopharmaceutical="" in="" the="" biologic="" matrix="" (e.g.,="" plasma,="" serum,="" cerebral="" spinal="" fluid)="" and="" the="" possible="" influence="" of="" binding="" proteins="" is="" important="" for="" understanding="" the="" pharmacodynamic="" effect.="" 4.3="" single="" dose="" toxicity="" studies="" single="" dose="" studies="" may="" generate="" useful="" data="" to="" describe="" the="" relationship="" of="" dose="" to="" systemic="" and/or="" local="" toxicity.="" these="" data="" can="" be="" used="" to="" select="" doses="" for="" repeated="" dose="" toxicity="" studies.="" information="" on="" dose-response="" relationships="" may="" be="" gathered="" through="" the="" conduct="" of="" a="" single="" dose="" toxicity="" study="" or="" as="" a="" component="" of="" pharmacology="" or="" animal="" model="" efficacy="" studies.="" the="" incorporation="" of="" safety="" pharmacology="" parameters="" in="" the="" design="" of="" these="" studies="" should="" be="" considered.="" 4.4="" repeated="" dose="" toxicity="" studies="" for="" consideration="" of="" the="" selection="" of="" animal="" species="" for="" repeated="" dose="" studies,="" see="" section="" 3.3.="" the="" route="" and="" dosing="" regimen="" (e.g.,="" daily="" versus="" intermittent="" dosing)="" should="" reflect="" the="" intended="" clinical="" use="" or="" exposure.="" when="" feasible,="" these="" studies="" should="" include="" toxicokinetics.="" a="" recovery="" period="" should="" generally="" be="" included="" in="" study="" designs="" to="" determine="" the="" reversal="" or="" potential="" worsening="" of="" pharmacological/="" toxicological="" effects,="" and/or="" potential="" delayed="" toxic="" effects.="" for="" biopharmaceuticals="" that="" induce="" prolonged="" pharmacological/="" toxicological="" effects,="" recovery="" group="" animals="" should="" be="" monitored="" until="" reversibility="" is="" demonstrated.="" the="" duration="" of="" repeated="" dose="" studies="" should="" be="" based="" on="" the="" intended="" duration="" of="" clinical="" exposure="" and="" disease="" indication.="" this="" duration="" of="" animal="" dosing="" has="" generally="" been="" 1-3="" months="" for="" most="" biotechnology-derived="" pharmaceuticals.="" for="" biopharmaceuticals="" intended="" for="" short-term="" use="" (e.g.,="">< to="" 7="" days)="" and="" for="" acute="" life-threatening="" diseases,="" repeated="" dose="" studies="" up="" to="" 2="" weeks="" duration="" have="" been="" considered="" adequate="" to="" support="" clinical="" studies="" as="" well="" as="" marketing="" authorization.="" for="" those="" biopharmaceuticals="" intended="" for="" chronic="" indications,="" studies="" of="" 6="" months="" duration="" have="" generally="" been="" appropriate,="" although="" in="" some="" cases="" shorter="" or="" longer="" durations="" have="" supported="" marketing="" authorizations.="" for="" biopharmaceuticals="" intended="" for="" chronic="" use,="" the="" duration="" of="" long-term="" toxicity="" studies="" should="" be="" scientifically="" justified.="" 4.5="" immunotoxicity="" studies="" one="" aspect="" of="" immunotoxicological="" evaluation="" includes="" assessment="" of="" potential="" immunogenicity="" (see="" section="" 3.6).="" many="" biotechnology-="" derived="" pharmaceuticals="" are="" intended="" to="" stimulate="" or="" suppress="" the="" immune="" system="" and,="" therefore,="" may="" affect="" not="" only="" humoral="" but="" also="" cell-mediated="" immunity.="" inflammatory="" reactions="" at="" the="" injection="" site="" may="" be="" indicative="" of="" a="" stimulatory="" response.="" it="" is="" important,="" however,="" to="" recognize="" that="" simple="" injection="" trauma="" and/or="" specific="" toxic="" effects="" caused="" by="" the="" formulation="" vehicle="" may="" also="" result="" in="" toxic="" changes="" at="" the="" injection="" site.="" in="" addition,="" the="" expression="" of="" surface="" antigens="" on="" target="" cells="" may="" be="" altered,="" which="" has="" implications="" for="" autoimmune="" potential.="" immunotoxicological="" testing="" strategies="" may="" require="" screening="" studies="" followed="" by="" mechanistic="" studies="" to="" clarify="" such="" issues.="" routine="" tiered="" testing="" approaches="" or="" standard="" testing="" batteries,="" however,="" are="" not="" recommended="" for="" biotechnology-derived="" pharmaceuticals.="" 4.6="" reproductive="" performance="" and="" developmental="" toxicity="" studies="" the="" need="" for="" reproductive/developmental="" toxicity="" studies="" is="" dependent="" upon="" the="" product,="" clinical="" indication="" and="" intended="" patient="" population="" (note="" 2).="" the="" specific="" study="" design="" and="" dosing="" schedule="" may="" be="" modified="" based="" on="" issues="" related="" to="" species="" specificity,="" immunogenicity,="" biological="" activity,="" and/or="" a="" long="" elimination="" half-="" life.="" for="" example,="" concerns="" regarding="" potential="" developmental="" immunotoxicity,="" which="" may="" apply="" particularly="" to="" certain="" monoclonal="" antibodies="" with="" prolonged="" immunological="" effects,="" could="" be="" addressed="" in="" a="" study="" design="" modified="" to="" assess="" immune="" function="" of="" the="" neonate.="" 4.7="" genotoxicity="" studies="" the="" range="" and="" type="" of="" genotoxicity="" studies="" routinely="" conducted="" for="" pharmaceuticals="" are="" not="" applicable="" to="" biotechnology-derived="" pharmaceuticals="" and="" therefore="" are="" not="" needed.="" moreover,="" the="" administration="" of="" large="" quantities="" of="" peptides/proteins="" may="" yield="" uninterpretable="" results.="" it="" is="" not="" expected="" that="" these="" substances="" would="" interact="" directly="" with="" dna="" or="" other="" chromosomal="" material="" (note="" 3).="" studies="" in="" available="" and="" relevant="" systems,="" including="" newly="" developed="" systems,="" should="" be="" performed="" in="" those="" cases="" where="" there="" is="" cause="" for="" concern="" about="" the="" product="" (e.g.,="" because="" of="" the="" presence="" of="" an="" organic="" linker="" molecule="" in="" a="" conjugated="" protein="" product).="" the="" use="" of="" standard="" genotoxicity="" studies="" for="" assessing="" the="" genotoxic="" potential="" of="" process="" contaminants="" is="" not="" considered="" appropriate.="" if="" performed="" for="" this="" purpose,="" however,="" the="" rationale="" should="" be="" provided.="" [[page="" 61519]]="" 4.8="" carcinogenicity="" studies="" standard="" carcinogenicity="" bioassays="" are="" generally="" inappropriate="" for="" biotechnology-derived="" pharmaceuticals.="" however,="" product-specific="" assessment="" of="" carcinogenic="" potential="" may="" still="" be="" needed="" depending="" upon="" duration="" of="" clinical="" dosing,="" patient="" population,="" and/or="" biological="" activity="" of="" the="" product="" (e.g.,="" growth="" factors,="" immunosuppressive="" agents,="" etc.).="" when="" there="" is="" a="" concern="" about="" carcinogenic="" potential,="" a="" variety="" of="" approaches="" may="" be="" considered="" to="" evaluate="" risk.="" products="" that="" may="" have="" the="" potential="" to="" support="" or="" induce="" proliferation="" of="" transformed="" cells="" and="" clonal="" expansion="" possibly="" leading="" to="" neoplasia="" should="" be="" evaluated="" with="" respect="" to="" receptor="" expression="" in="" various="" malignant="" and="" normal="" human="" cells="" that="" are="" potentially="" relevant="" to="" the="" patient="" population="" under="" study.="" the="" ability="" of="" the="" product="" to="" stimulate="" growth="" of="" normal="" or="" malignant="" cells="" expressing="" the="" receptor="" should="" be="" determined.="" when="" in="" vitro="" data="" give="" cause="" for="" concern="" about="" carcinogenic="" potential,="" further="" studies="" in="" relevant="" animal="" models="" may="" be="" needed.="" incorporation="" of="" sensitive="" indices="" of="" cellular="" proliferation="" in="" long-term="" repeated="" dose="" toxicity="" studies="" may="" provide="" useful="" information.="" in="" those="" cases="" where="" the="" product="" is="" biologically="" active="" and="" nonimmunogenic="" in="" rodents="" and="" other="" studies="" have="" not="" provided="" sufficient="" information="" to="" allow="" an="" assessment="" of="" carcinogenic="" potential,="" then="" the="" utility="" of="" a="" single="" rodent="" species="" should="" be="" considered.="" careful="" consideration="" should="" be="" given="" to="" the="" selection="" of="" doses.="" the="" use="" of="" a="" combination="" of="" pharmacokinetic="" and="" pharmacodynamic="" endpoints="" with="" consideration="" of="" comparative="" receptor="" characteristics="" and="" intended="" human="" exposures="" represents="" the="" most="" scientifically="" based="" approach="" for="" defining="" the="" appropriate="" doses.="" the="" rationale="" for="" the="" selection="" of="" doses="" should="" be="" provided.="" 4.9="" local="" tolerance="" studies="" local="" tolerance="" should="" be="" evaluated.="" the="" formulation="" intended="" for="" marketing="" should="" be="" tested;="" however,="" in="" certain="" justified="" cases,="" the="" testing="" of="" representative="" formulations="" may="" be="" acceptable.="" in="" some="" cases,="" the="" potential="" adverse="" effects="" of="" the="" product="" can="" be="" evaluated="" in="" single="" or="" repeated="" dose="" toxicity="" studies,="" thus="" obviating="" the="" need="" for="" separate="" local="" tolerance="" studies.="" notes="" note="" 1="" animal="" models="" of="" disease="" may="" be="" useful="" in="" defining="" toxicity="" endpoints,="" selection="" of="" clinical="" indications,="" and="" determination="" of="" appropriate="" formulations,="" route="" of="" administration,="" and="" treatment="" regimen.="" it="" should="" be="" noted="" that="" with="" these="" models="" of="" disease="" there="" is="" often="" a="" paucity="" of="" historical="" data="" for="" use="" as="" a="" reference="" when="" evaluating="" study="" results.="" therefore,="" the="" collection="" of="" concurrent="" control="" and="" baseline="" data="" is="" critical="" to="" optimize="" study="" design.="" note="" 2="" there="" may="" be="" extensive="" public="" information="" available="" regarding="" potential="" reproductive="" and/or="" developmental="" effects="" of="" a="" particular="" class="" of="" compounds="" (e.g.,="" interferons)="" where="" the="" only="" relevant="" species="" is="" the="" nonhuman="" primate.="" in="" such="" cases,="" mechanistic="" studies="" indicating="" that="" similar="" effects="" are="" likely="" to="" be="" caused="" by="" a="" new="" but="" related="" molecule="" may="" obviate="" the="" need="" for="" formal="" reproductive/="" developmental="" toxicity="" studies.="" in="" each="" case,="" the="" scientific="" basis="" for="" assessing="" the="" potential="" for="" possible="" effects="" on="" reproduction/="" development="" should="" be="" provided.="" note="" 3="" with="" some="" biopharmaceuticals,="" there="" is="" a="" potential="" concern="" about="" accumulation="" of="" spontaneously="" mutated="" cells="" (e.g.,="" via="" facilitating="" a="" selective="" advantage="" of="" proliferation)="" leading="" to="" carcinogenicity.="" the="" standard="" battery="" of="" genotoxicity="" tests="" is="" not="" designed="" to="" detect="" these="" conditions.="" alternative="" in="" vitro="" or="" in="" vivo="" models="" to="" address="" such="" concerns="" may="" have="" to="" be="" developed="" and="" evaluated.="" dated:="" november="" 12,="" 1997.="" william="" k.="" hubbard,="" associate="" commissioner="" for="" policy="" coordination.="" [fr="" doc.="" 97-30274="" filed="" 11-17-97;="" 8:45="" am]="" billing="" code="" 4160-01-f="">