[Federal Register Volume 63, Number 110 (Tuesday, June 9, 1998)]
[Notices]
[Pages 31506-31513]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-15193]


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DEPARTMENT OF HEALTH AND HUMAN SERVICES

Food and Drug Administration
[Docket No. 98D-0374]


International Conference on Harmonisation; Draft Guidance on 
Specifications: Test Procedures and Acceptance Criteria for 
Biotechnological/Biological Products

AGENCY: Food and Drug Administration, HHS.

ACTION: Notice.

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SUMMARY: The Food and Drug Administration (FDA) is publishing a draft 
guidance entitled ``Q6B Specifications: Test Procedures and Acceptance 
Criteria for Biotechnological/Biological Products.'' The draft guidance 
was prepared under the auspices of the International Conference on 
Harmonisation of Technical Requirements for Registration of 
Pharmaceuticals for Human Use (ICH). The draft guidance provides 
guidance on general principles for the selection of test procedures and 
the setting and justification of acceptance criteria for 
biotechnological and biological products. The draft guidance is 
intended to assist in the establishment of a uniform set of 
international specifications for biotechnological and biological 
products to support new marketing applications.

DATES: Written comments by July 24, 1998.
ADDRESSES: Submit written comments on the draft guidance to the Dockets 
Management Branch (HFA-305), Food and Drug Administration, 12420 
Parklawn Dr., rm. 1-23, Rockville, MD 20857. Copies of the draft 
guidance are available from the Drug Information Branch (HFD-210), 
Center for Drug

[[Page 31507]]

Evaluation and Research, Food and Drug Administration, 5600 Fishers 
Lane, Rockville, MD 20857, 301-827-4573. Single copies of the 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: Neil D. Goldman, Center for Biologics 
Evaluation and Research (HFM-20), Food and Drug Administration, 1401 
Rockville Pike, Rockville, MD 20852, 301-827-0377.
    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 February 1998, the ICH Steering Committee agreed that a draft 
guidance entitled ``Q6B Specifications: Test Procedures and Acceptance 
Criteria for Biotechnological/Biological Products'' should be made 
available for public comment. The draft guidance is the product of the 
Quality Expert Working Group of the ICH. Comments about this draft will 
be considered by FDA and the Quality Expert Working Group.
    The draft guidance provides guidance on general principles for the 
selection of test procedures and the setting and justification of 
acceptance criteria for biotechnological and biological products. The 
draft guidance is intended to assist in the establishment of a uniform 
set of international specifications for biotechnological and biological 
products to support new marketing applications.
    This draft guidance represents the agency's current thinking on the 
selection of test procedures and the setting and justification of 
acceptance criteria for biotechnological/biological products. 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.
    Interested persons may, on or before July 24, 1998, submit to the 
Dockets Management Branch (address above) written comments on the draft 
guidance. 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 
draft 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 draft guidance is available on the Internet at ``<a href="http://
www.fda.gov/cder/guidance/index.htm">http://
www.fda.gov/cder/guidance/index.htm</a>'' or at CBER's World Wide Web site 
at ``http://www.fda.gov/cber/publications.htm''.
    The text of the draft guidance follows:

Q6B Specifications: Test Procedures and Acceptance Criteria for 
Biotechnological/Biological Products \1\
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    \1\ This draft guidance represents the agency's current thinking 
on the selection of test procedures and the setting and 
justification of acceptance criteria for biotechnological/biological 
products. 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.
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Table of Contents

1.0 Introduction
    1.1 Objective
    1.2 Scope
2.0 General Principles for Consideration in Setting Specifications
    2.1 Characterization
    2.1.1 Physicochemical Properties
    2.1.2 Biological Activity
    2.1.3 Immunochemical Properties
    2.1.4 Purity, Impurities, and Contaminants
    2.1.5 Quantity
    2.2 Analytical Considerations
    2.2.1 Reference Standards and Reference Materials
    2.2.2 Validation of Analytical Procedures
    2.3 Process Controls
    2.3.1 Process-Related Considerations
    2.3.2 In-Process Acceptance Criteria and Action Limits
    2.3.3 Raw Materials and Excipient Specifications
    2.4 Pharmacopoeial Specifications
    2.5 Release Limits versus Shelf-Life Limits
    2.6 Statistical Concepts
3.0 Justification of the Specification
4.0 Specifications
    4.1 Drug Substance Specification
    4.1.1 Appearance/Description
    4.1.2 Identity
    4.1.3 Purity and Impurities
    4.1.4 Potency
    4.1.5 Quantity
    4.2 Drug Product Specification
    4.2.1 Appearance/Description
    4.2.2 Identity
    4.2.3 Purity and Impurities
    4.2.4 Potency
    4.2.5 Quantity
    4.2.6 General Tests
    4.2.7 Additional Testing for Unique Dosage Forms
5.0 Glossary
6.0 Appendices
    6.1 Appendix for Physicochemical Characterization
    6.1.1 Structural Characterization/Confirmation
    6.1.2 Physicochemical Properties
    6.2 Appendix for Impurities
    6.2.1 Process-Related Impurities
    6.2.2 Product-Related Impurities

1.0  Introduction

    A specification is defined as a list of tests, references to 
analytical procedures, and appropriate acceptance criteria with 
numerical limits, ranges, or other criteria for the tests described. 
It establishes the set of criteria to which a drug substance, drug 
product, or materials at other stages of their manufacture should 
conform to be considered acceptable for their intended use.

[[Page 31508]]

 ``Conformance to specification'' means that the drug substance and 
drug product, when tested according to the listed analytical 
procedures, will meet the listed acceptance criteria. Specifications 
are binding quality standards that are proposed and justified by the 
manufacturer, and approved by regulatory authorities.
    Specifications are one part of a total control strategy designed 
to ensure product quality and consistency. Other parts of this 
strategy include thorough product characterization during 
development, upon which many of the specifications are based, a 
validated manufacturing process, raw materials testing, in-process 
testing, stability testing, etc.
    Specifications are chosen to confirm the quality of the drug 
substance and drug product rather than to establish full 
characterization and should focus on those molecular and biological 
characteristics found to be useful in ensuring the safety and 
efficacy of the product.

1.1 Objective

    This guidance document provides guidance on general principles 
for the setting and justification, to the extent possible, of a 
uniform set of international specifications for biotechnological/
biological products to support new marketing applications.

1.2  Scope

    The principles adopted and explained in this document apply to 
proteins and polypeptides, their derivatives, and products of which 
they are components (e.g., conjugates). These proteins and 
polypeptides are produced from recombinant or nonrecombinant cell-
culture expression systems and can be highly purified and 
characterized using an appropriate set of analytical procedures.
    The principles outlined in this document may also apply to other 
product types, such as proteins and polypeptides isolated from 
tissues and body fluids. To determine applicability, manufacturers 
should consult with the appropriate regulatory authorities.
    This document does not cover antibiotics, synthetic peptides/
polypeptides, heparins, vitamins, cell metabolites, DNA products, 
allergenic extracts, conventional vaccines, cells, whole blood, and 
cellular blood components.
    This document does not recommend specific test procedures or 
acceptance criteria that should be established for the proposed 
value, nor does it apply to the regulation of preclinical and/or 
clinical research material.

2.0 General Principles for Consideration in Setting Specifications

2.1  Characterization

    Characterization of a biotechnological/biological product (which 
includes the determination of physicochemical properties, biological 
activity, immunochemical properties, purity, and impurities) is 
necessary to allow relevant specifications to be established. 
Acceptance criteria should be established and justified based on 
data obtained from lots used in preclinical/clinical studies, data 
from lots used for demonstration of manufacturing consistency, and 
relevant development data, such as those arising from analytical 
procedures and stability studies.
    Extensive characterization usually is performed only in the 
development phase and, where necessary, following significant 
process changes. At the time of submission, the product should have 
been compared with an appropriate reference standard, if available. 
When feasible and relevant, it should be compared with its natural 
counterpart. Also, at the time of submission, the manufacturer 
should have established appropriately characterized in-house 
reference materials (primary and working) which will serve for 
biological assay and physicochemical testing of production lots.

2.1.1 Physicochemical properties

    A physicochemical characterization program will generally 
include a determination of the composition, physical properties, and 
primary structure of the desired product. In some cases, information 
regarding higher-order structure of the desired product (the 
fidelity of which is generally inferred by its biological activity) 
may be obtained by appropriate physicochemical methodologies.
    An inherent degree of structural heterogeneity occurs in 
proteins due to the biosynthetic processes used by living organisms 
to produce them; therefore, the desired product can be a mixture of 
anticipated post-translationally modified forms (e.g., glycoforms). 
These forms may be active and their presence has no deleterious 
effect on the safety and efficacy of the product (section 2.1.4). 
The manufacturer should define the pattern of heterogeneity of the 
desired product and demonstrate consistency with that of the lots 
used in preclinical/clinical studies. If a consistent pattern of 
product heterogeneity is demonstrated, an evaluation of the 
activity, efficacy, and safety (including immunogenicity) of 
individual forms may not be necessary.
    Heterogeneity can also be produced during manufacture and/or 
during storage of the drug substance or drug product. Since the 
heterogeneity of these products defines their quality, the degree 
and profile of this heterogeneity should be characterized to ensure 
lot-to-lot consistency. When these variants of the desired product 
have properties comparable to those of the desired product with 
respect to activity, efficacy, and safety, they are considered 
product-related substances. When process changes and degradation 
products result in heterogeneity patterns that differ from those 
observed in the material used during preclinical and clinical 
development, the significance of these alterations should be 
evaluated.
    Analytical methods to elucidate physicochemical properties are 
listed in appendix 6.1. New analytical technology and modifications 
to existing technology are continually being developed. Such 
technologies should be utilized when appropriate.
    For the purpose of lot release (section 4), an appropriate 
subset of these methods should be selected and justified.

2.1.2 Biological activity

    Assessment of the biological properties constitutes an equally 
essential step in establishing a complete characterization profile. 
An important property is the biological activity which describes the 
specific ability or capacity of a product to achieve its intended 
biological effect.
    A valid biological assay to measure the biological activity 
should be provided by the manufacturer. Examples of procedures used 
to measure biological activity include:
    <bullet>   Animal-based biological assays, which measure an 
organism's biological response to the product;
    <bullet>   Cell culture-based biological assays, which measure 
biochemical or physiological response at the cellular level; and
    <bullet>   Biochemical assays, which measure biological 
activities such as enzymatic reaction rates or biological responses 
induced by immunological interactions.
    Other procedures, such as ligand/receptor binding assays, may be 
acceptable.
    Potency (expressed in units) is the quantitative measure of 
biological activity based on the attribute of the product that is 
linked to the relevant biological properties, whereas quantity 
(expressed in mass) is a physicochemical measure of protein content. 
Although mimicking the biological activity in the clinical situation 
is not necessary, a correlation between the expected clinical 
response and the activity in the biological assay should be 
established.
    The results of biological assays should be expressed in units of 
activity calibrated against an international or national reference 
standard, when available and appropriate for the assay utilized. 
Where no such reference standard exists, a characterized ``in-
house'' reference material should be established and assay results 
of production lots reported as ``in-house'' units.
    Often, for complex molecules, the physicochemical information 
may be extensive but unable to confirm the higher order structure 
which, however, can be inferred from the biological activity. In 
such cases, a biological assay, with wider confidence limits, may be 
acceptable when combined with a specific quantitative measure. 
Importantly, a biological assay to measure the biological activity 
of the product may be replaced by physicochemical tests only in 
those instances where:
    <bullet>  Sufficient physicochemical information about the drug, 
including higher order structure, can be thoroughly established by 
such physicochemical methods, and relevant correlates to biologic 
activity demonstrated; and
    <bullet>  There exists a well-established manufacturing history.
    Where physicochemical tests alone are used to quantitate the 
biological activity (based on appropriate correlation), results 
should be expressed in mass.
    For the purpose of lot release (section 4), the choice of 
relevant quantitative assay (biological and/or physicochemical) 
should be justified by the manufacturer.

2.1.3 Immunochemical properties

    When an antibody is the desired product, its immunological 
properties should be fully

[[Page 31509]]

characterized. Binding assays of the antibody to purified antigens 
and defined regions of antigens should be performed, as feasible, to 
determine affinity, avidity, and immunoreactivity (including cross-
reactivity). In addition, the target molecule bearing the relevant 
epitope should be biochemically defined and the epitope itself 
defined, when feasible.
    For some drug substances/drug products, the protein molecule may 
need to be examined using immunochemical procedures (e.g., ELISA, 
Western Blot) utilizing antibodies that recognize different epitopes 
of the protein molecule. Immunochemical properties of a protein may 
serve to establish its identity, homogeneity, or purity, or serve to 
quantify it.
    If immunochemical properties constitute lot release criteria, 
all relevant information pertaining to the antibody should be made 
available.

2.1.4 Purity, impurities, and contaminants

    <bullet>  Purity
    The determination of absolute, as well as relative, purity 
presents considerable analytical challenges, and the results are 
highly method-dependent. Historically, the relative purity of a 
biological product has been expressed in terms of specific activity 
(units of biological activity per milligram of product), which is 
also highly method-dependent. Consequently, the purity of the drug 
substance and drug product is assessed by a combination of 
analytical procedures.
    Due to the unique biosynthetic production process and molecular 
characteristics of biotechnological/biological products, the drug 
substance can include several molecular entities or variants. When 
these molecular entities are derived from anticipated post-
translational modification, they are part of the desired product. 
When variants of the desired product are formed during the 
manufacturing process and have properties comparable to the desired 
product, they are considered product-related substances and not 
impurities (see section 2.1.1).
    Individual and/or collective acceptance criteria for product-
related substances should be set, as appropriate.
    For the purpose of lot release (section 4), an appropriate 
subset of methods should be selected and justified for determination 
of purity.
    <bullet>  Impurities
    In addition to evaluating the purity of the drug substance/drug 
product, which may be composed of the desired product and multiple 
product-related substances, the manufacturer should also assess 
impurities which may be present. Impurities may be either process- 
or product-related. They can be of known structure, partially 
characterized, or unidentified. When adequate quantities of 
impurities can be isolated, the identity of these materials should 
be determined as a minimum requirement and, where possible, their 
biological activities should be evaluated.
    Process-related impurities encompass those that are derived from 
the manufacturing process, i.e., derived from the culture (e.g., 
inducers, antibiotics, or media components) or from downstream 
processing (see appendix section 6.2.1). Product-related impurities 
(e.g., certain degradation products) are molecular variants arising 
from processing or during storage, which do not have properties 
comparable to those of the desired product with respect to activity, 
efficacy, and safety.
    Further, the acceptance criteria for impurities should be based 
on data obtained for lots used in preclinical and clinical studies 
and manufacturing consistency lots.
    Individual and/or collective acceptance criteria for impurities 
(product-related and process-related) should be set, as appropriate. 
Under certain circumstances, acceptance criteria for selected 
impurities may not be necessary (section 2.3).
    Examples of analytical procedures that may be employed to test 
for the presence of impurities are listed in appendix 6.2. New 
analytical technology and modifications to existing technology are 
continually being developed. Such technologies should be utilized 
when appropriate.
    For the purpose of lot release (section 4), an appropriate 
subset of these methods should be selected and justified.
    <bullet>  Contaminants
    Contaminants in a product include all adventitiously introduced 
materials not intended to be part of the manufacturing process, such 
as chemical/biochemical materials (e.g., microbial proteases) and/or 
microbial species. Contaminants should be strictly avoided and/or 
suitably controlled with appropriate in-process acceptance criteria 
or action limits or drug substance/drug product specifications (see 
section 2.3). For the special case of adventitious viral or 
mycoplasma contamination, the concept of action limits is not 
applicable, and the strategies proposed in ICH guidances Q5A 
``Quality of Biotechnological/Biological Products: Viral Safety 
Evaluation of Biotechnology Products Derived from Cell Lines of 
Human or Animal Origin'' and Q5D ``Quality of Biotechnological/
Biological Products: Derivation and Characterization of Cell 
Substrates Used for Production of Biotechnological/Biological 
Products'' should be considered.

2.1.5 Quantity

    Quantity, usually measured as protein content, is critical for a 
biotechnological/biological product and should be determined using 
an appropriate assay, usually physicochemical in nature. In some 
cases, it may be demonstrated that the quantity values obtained may 
be directly related to those found using the biological assay. When 
this correlation exists, it may be appropriate to use measurement of 
quantity rather than measurement of biological activity to determine 
manufacturing parameters, such as for filling.

2.2 Analytical Considerations

2.2.1 Reference standards and reference materials

    For drug applications for new molecular entities, it is unlikely 
that an international or national standard will be available. At the 
time of submission, the manufacturer should have established an 
appropriately characterized in-house primary reference material, 
prepared from lot(s) representative of production and clinical 
materials. In-house working reference material(s) used in the 
testing of production lots should be calibrated against this primary 
reference material. Where an international or national standard is 
available and appropriate, reference materials should be calibrated 
against it. While it is desirable to use the same reference material 
for both biological assays and physicochemical testing, in some 
cases, a separate reference material may be necessary. Also, 
distinct reference materials for product-related substances, 
product-related impurities, and process-related impurities may need 
to be established. When appropriate, a description of the 
manufacture and/or purification of reference materials should be 
included in the application. Documentation of the characterization, 
storage conditions, and formulation supportive of reference 
material(s) stability should also be provided.

2.2.2 Validation of analytical procedures

    At the time the application is submitted to the regulatory 
authorities, applicants should have validated the analytical 
procedures used in the specifications in accordance with the ICH 
guidances Q2A ``Validation of Analytical Procedures: Definitions and 
Terminology'' and Q2B ``Validation of Analytical Procedures: 
Methodology,'' except where there are specific issues for unique 
tests used for analyzing biotechnological/biological products.

2.3 Process Controls

2.3.1 Process-related considerations

    Adequate design of a process and knowledge of its capability are 
part of the strategy used to develop a manufacturing process that is 
controlled and reproducible, yielding a drug substance/drug product 
which meets specifications. In this respect, limits are justified 
based on critical information gained from the entire process 
spanning the period from early development through commercial-scale 
production.
    For certain impurities, testing on either the drug substance or 
the drug product may not be necessary and may not need to be 
included in the specifications if efficient control or removal to 
acceptable levels is demonstrated by suitable studies. This can 
include verification at commercial-scale in accordance with regional 
regulations. It is recognized that only limited data may be 
available at the time of submission of an application. This concept 
may, therefore, sometimes be implemented after marketing 
authorization, in accordance with regional regulations.

2.3.2 In-process acceptance criteria and action limits

    In-process tests are performed at critical decision making steps 
and at points where data serve to confirm consistency of the process 
during the production of either the drug substance or the drug 
product. The in-process test results may be recorded as action 
limits or reported as acceptance criteria. Monitoring for the 
presence of mycoplasma and adventitious virus at the end of a cell 
culture harvest and/or other stages is an example of testing for 
which in-process acceptance criteria should be set. Performing

[[Page 31510]]

such testing may eliminate the need for testing of the drug 
substance/drug product (section 2.3.1).
    The use of internal action limits by the manufacturer to assess 
the consistency of the process at less critical steps is also 
important. Data obtained during development and validation runs 
should provide the basis for provisional action limits to be set for 
the manufacturing process. These limits, which are the 
responsibility of the manufacturer, should be further refined as 
increased experience and data are obtained after product approval.

2.3.3 Raw materials and excipient specifications

    The quality of the raw materials used in the production of the 
drug substance (or drug product) should meet acceptable standards, 
appropriate for their intended use. Biological raw materials or 
reagents may require careful evaluation to establish the presence or 
absence of deleterious endogenous or adventitious agents. Procedures 
that make use of affinity chromatography (for example, employing 
monoclonal antibodies) should be accompanied by appropriate measures 
to ensure that such process-related impurities or potential 
contaminants arising from their production and use do not compromise 
the quality and safety of the drug substance/drug product. 
Appropriate information pertaining to the antibody should be made 
available.
    The quality of the excipients used in the drug product 
formulation (and in some cases, in the drug substance), as well as 
the container closure systems, should meet pharmacopoeial standards, 
where available and appropriate. Otherwise, suitable acceptance 
criteria should be established for the nonpharmacopoeial excipients.

2.4 Pharmacopoeial Specifications

    Pharmacopoeias contain important requirements pertaining to 
certain analytical procedures and acceptance criteria which, where 
relevant, are part of the evaluation of either the drug substance or 
drug product. Such monographs, applicable to biotechnological/
biological products, generally include, but are not limited to, 
tests for sterility, endotoxins, bioburden, volume in container, 
uniformity of dosage forms, and particulate matter. With respect to 
the use of pharmacopoeial methods and acceptance criteria, the value 
of this guidance is linked to the extent of harmonization of the 
analytical procedures of the pharmacopoeias. The pharmacopoeias are 
committed to developing identical or methodologically equivalent 
test procedures and acceptance criteria.

2.5 Release Limits Versus Shelf-Life Limits

    The concept of release limits versus shelf-life limits may be 
applied where justified. This concept pertains to the establishment 
of limits which are tighter for the release than for the shelf-life 
of the drug substance/drug product. Examples where this may be 
applicable include potency and degradation products. In some 
regions, the concept of release limits may only be applicable to in-
house limits and not to the regulatory shelf-life limits.

2.6 Statistical Concepts

    Appropriate statistical analysis should be applied, when 
necessary, to quantitative data reported. The methods of analysis, 
including justification and rationale, should be described fully. 
These descriptions should be sufficiently clear to permit 
independent calculation of the results presented.

3.0 Justification of the Specification

    The setting of specifications for drug substance and drug 
product is part of an overall control strategy which includes 
control of raw materials and excipients, in-process testing, process 
evaluation/validation, stability testing, and testing for 
consistency of lots. When combined in total, these elements provide 
assurance that the appropriate quality of the product will be 
maintained. Since specifications are chosen to confirm the quality 
rather than to characterize the product, the manufacturer should 
provide the rationale and justification for including and/or 
excluding testing for specific quality attributes. The following 
points should be taken into consideration when establishing 
scientifically justifiable specifications.
    <bullet>   Specifications are linked to a manufacturing process.
    Specifications should be based on data obtained from lots used 
to demonstrate manufacturing consistency. Linking specifications to 
a manufacturing process is important, especially for product-related 
substances, product-related impurities, and process-related 
impurities. Process changes and degradation products produced during 
storage may result in heterogeneity patterns which differ from those 
observed in the material used during preclinical and clinical 
development. The significance of these alterations should be 
evaluated.
    <bullet>   Specifications should account for the stability of 
drug substance and drug product.
    Degradation of drug substance and drug product, which may occur 
during storage, should be considered when establishing 
specifications. Due to the inherent complexity of these products, 
there is no single stability-indicating assay or parameter that 
profiles the stability characteristics. Consequently, the 
manufacturer should propose a stability-indicating profile. The 
result of this stability-indicating profile will then provide 
assurance that changes in the quality of the product will be 
detected. The determination of which tests should be included will 
be product-specific. The manufacturer is referred to the ICH 
guidance Q5C ``Stability Testing of Biotechnological/Biological 
Products.''
    <bullet>   Specifications are linked to preclinical and clinical 
studies.
    Specifications should be based on data obtained for lots used in 
preclinical and clinical studies. The quality of the material made 
at commercial scale should be representative of the lots used in 
preclinical and clinical studies.
    <bullet>   Specifications are linked to analytical procedures.
    Critical quality attributes may include items such as potency, 
the nature and quantity of product-related substances, product-
related impurities, and process-related impurities. Such attributes 
can be assessed by multiple analytical procedures, each yielding 
different results. In the course of product development, it is not 
unusual for the analytical technology to evolve in parallel with the 
product. Therefore, it is important to confirm that data generated 
during development correlate with those generated at the time the 
marketing application is filed.

4.0 Specifications

    Selection of tests to be included in the specifications is 
product specific. The rationale used to establish the acceptable 
range of acceptance criteria should be described. Acceptance 
criteria should be established and justified based on data obtained 
from lots used in preclinical/clinical studies, lots used for 
demonstration of manufacturing consistency, and relevant development 
data, such as those arising from analytical procedures and stability 
studies.
    In some cases, testing at production stages rather than testing 
the finished drug substance or drug product may be appropriate and 
acceptable. In such circumstances, test results should be considered 
as in-process acceptance criteria and included in the specification 
of drug substance or drug product in accordance with the 
requirements of the regional regulatory authorities.

4.1 Drug Substance Specification

    Generally, the following tests and acceptance criteria are 
considered applicable to all drug substances. Pharmacopoeial tests 
(e.g., endotoxin detection) should be performed on the drug 
substance, where appropriate. Additional drug substance specific 
acceptance criteria may also be necessary.

4.1.1 Appearance/description

    A qualitative statement describing the physical state (e.g., 
solid, liquid) and color of a drug substance should be provided.

4.1.2 Identity

    The identity test(s) should be specific for the drug substance 
and should be based on unique aspects of its molecular structure 
and/or other specific properties. More than one test 
(physicochemical, biological, and/or immunochemical) may be 
necessary to establish identity. The identity test(s) for a drug 
substance can be qualitative in nature and, generally, need not be 
highly sensitive. Some of the methods typically used for 
characterization of the product as described in section 2.1 and in 
appendix 6.1 may be employed and/or modified as appropriate for the 
purpose of establishing identity.

4.1.3 Purity and impurities

    Since the absolute purity of biotechnological/biological 
products is difficult to determine and the results are method-
dependent (section 2.1.4), the purity of the drug substance is 
usually estimated by a combination of methods.
    The impurities observed in these products are classified as 
process-related and product-related:
    <bullet>   Process-related impurities (section 2.1.4) in the 
drug substance may include culture media, host cell proteins, DNA,

[[Page 31511]]

monoclonal antibodies and chromatographic media used in 
purification, solvents/buffer components. These impurities should be 
minimized by the use of appropriate well-controlled manufacturing 
processes.
    <bullet>   Product-related impurities (section 2.1.4) in the 
drug substance are molecular variants with properties different from 
those of the desired product resulting from processing or from 
storage.
    The choice and optimization of analytical procedures should 
focus on the separation of the desired product and product-related 
substances from impurities. Individual and/or collective acceptance 
criteria for impurities should be set, as appropriate. Under certain 
circumstances, acceptance criteria for selected impurities may not 
be necessary.

4.1.4 Potency

    A relevant, validated potency assay (section 2.1.2) should be 
part of the specifications for a biological/biotechnological drug 
substance and/or drug product. When an appropriate potency assay is 
used for the drug product, an alternative method (physicochemical 
and/or biological) may suffice for quantitative assessment at the 
drug substance stage (section 4.2.4). In some cases, the measurement 
of specific activity may provide additional useful information.

4.1.5 Quantity

    The quantity of the drug substance, usually based on protein 
content (mass), should be determined using an appropriate assay. The 
quantity determination may be reference standard/material 
independent. In cases where product manufacture is based upon 
potency, there may be no need for an alternate determination of 
quantity.

4.2 Drug Product Specification

    Generally, the following tests and acceptance criteria are 
considered applicable to all drug products. Each section (4.2.1-
4.2.5) is cross referenced to respective sections (4.1.1-4.1.5) 
under Drug Substance Specification. Pharmacopoeial requirements 
apply to the relevant dosage forms. Typical tests found in the 
pharmacopoeia include, but are not limited to, sterility, endotoxin, 
microbial limits, volume in container, particulate matter, 
uniformity of dosage forms, and moisture content for lyophilized 
drug products. If appropriate, testing for uniformity of dosage form 
may be performed as in-process controls and corresponding acceptance 
criteria are set.

4.2.1 Appearance/description

    A qualitative statement describing the physical state (e.g., 
solid, liquid), color, and clarity of the drug product should be 
provided.

4.2.2 Identity

    The identity test(s) should be specific for the drug product and 
should be based on unique aspects of its molecular structure and 
other specific properties. The identity test(s) can be qualitative 
in nature and generally need not be highly sensitive. While it is 
recognized that in most cases a single test is adequate, more than 
one test (physicochemical, biological, and/or immunochemical) may be 
necessary to establish identity for some products. Some of the 
methods typically used for characterization of the product as 
described in section 2.1 and in appendix 6.1 may be employed and/or 
modified as appropriate for the purpose of establishing identity.

4.2.3 Purity and impurities

    Impurities may be generated or increase in the manufacture of 
the drug product. These may be either the same as those occurring in 
the drug substance itself, process-related, or degradation products 
which form specifically in the drug product during formulation or 
during storage. If impurities are qualitatively and quantitatively 
(i.e., relative amounts and/or concentrations) the same as in the 
drug substance, testing is not considered necessary. If impurities 
are known to be introduced or formed during the production of the 
drug product, the levels of these impurities should be determined 
and acceptance criteria established.
    Acceptance criteria and analytical procedures should be 
developed and justified, based upon previous experience with the 
drug product, to measure changes in the drug substance during the 
manufacture of the drug product.
    The choice and optimization of analytical procedures should 
focus on the separation of the desired product and product-related 
substances from excipients and impurities including degradation 
products inherent in the drug product.

4.2.4 Potency

    A relevant, validated potency assay (section 2.1.2) should be 
part of the specifications for a biological/biotechnological drug 
substance and/or drug product. When an appropriate potency assay is 
used for the drug substance, an alternative method (physicochemical 
and/or biological) may suffice for quantitative assessment of the 
drug product (section 4.1.4).

4.2.5 Quantity

    The quantity of the drug substance in the drug product, usually 
based on protein content, should be determined using an appropriate 
assay. In cases where product manufacture is based upon potency, 
there may be no need for an alternate determination of quantity.

4.2.6 General tests

    Physical description and the measurement of other quality 
attributes are often important for the evaluation of the drug 
product functions. Examples of such tests include pH and osmolarity.

4.2.7 Additional testing for unique dosage forms

    It should be recognized that certain unique dosage forms may 
need additional tests other than those mentioned above.

5.0 Glossary

    Acceptance criteria: Numerical limits, ranges, or other suitable 
measures for acceptance which the drug substance or drug product or 
materials at other stages of their manufacture should meet to 
conform with the specification of the results of analytical 
procedures.
    Action limits: An action limit is an internal (in-house) value 
used to assess the consistency of the process at less critical 
steps. These limits are the responsibility of the manufacturer.
    Biological activity: Biological activity describes the specific 
ability or capacity of the product to achieve its intended 
biological effect. Potency is the quantitative measure of the 
biological activity.
    Contaminants: Any adventitiously introduced materials (e.g., 
chemical, biochemical, or microbial species) in the drug substance/
drug product not intended to be part of the manufacturing process.
    Degradation products: Degradation products are molecular 
variants resulting from changes in the desired product or product-
related substances brought about over time and/or by the action of, 
e.g., light, temperature, pH, water, or by reaction with an 
excipient and/or the immediate container/closure system. Such 
changes may occur as a result of processing and/or storage (e.g., 
deamidation, oxidation, aggregation, proteolysis). Degradation 
products may be either product-related substances or product-related 
impurities.
    Desired product: The protein that is expected from the DNA 
sequence and anticipated post-translational modifications (including 
glycoforms) and intended downstream processing necessary to produce 
an active biological molecule.
    Drug product (Dosage form; Finished product): A pharmaceutical 
product type that contains a drug substance, generally in 
association with excipients.
    Drug substance (Bulk material): The drug substance is the 
material which is subsequently formulated with excipients to produce 
the drug product. It can be composed of the desired product, 
product-related substances, and product- and process-related 
impurities. It may also contain excipients and other components, 
such as buffers.
    Excipient: An ingredient added intentionally to the drug product 
or drug substance which should not have pharmacological properties 
in the used quantity.
    Impurity: Any component present in the drug substance or drug 
product that is not the desired product, a product-related 
substance, or an excipient (including added buffer components). It 
may be either process- or product-related.
    Potency: Potency is the measure of the biological activity using 
a suitably quantitative biological assay (also called potency assay 
or bioassay), based on the attribute of the product which is linked 
to the relevant biological properties.
    Process-related impurities: Impurities that are derived from the 
manufacturing process. They may be derived from cell substrates, 
culture (e.g., inducers, antibiotics, or media components), or from 
downstream processing (e.g., processing reagents or column 
leachables).
    Product-related impurities: Product-related impurities are 
molecular variants of the desired product arising from processing or 
during storage (e.g., certain degradation products) which do not 
have properties comparable to those of the desired product with 
respect to activity, efficacy, and safety.

[[Page 31512]]

    Product-related substances: Product-related substances are 
molecular variants of the desired product which are active and have 
no deleterious effect on the safety and efficacy of the drug 
product. These variants possess properties comparable to the desired 
product and are not considered impurities.
    Raw material: Raw material is a collective name for substances 
or components used in the manufacture of the drug substance or drug 
product.
    Reference standards/materials: In addition to the existing 
international/national standards, it is usually necessary to create 
in-house reference materials.
    -- In-house primary reference material: A primary reference 
material is an appropriately characterized material prepared by the 
manufacturer from a representative lot(s) for the purpose of 
biological assay and physicochemical testing of subsequent lots, and 
against which in-house working reference material is calibrated.
    -- In-house working reference material: The in-house working 
reference material is a material prepared similarly to the primary 
reference material and is established solely to assess and control 
subsequent lots for the individual attribute in question. It is 
always calibrated against the in-house primary reference material.
    Specification: A specification is a list of tests, references to 
analytical procedures, and appropriate acceptance criteria with 
numerical limits, ranges, or other criteria for the tests described, 
which establishes the set of criteria to which a drug substance or 
drug product or materials at other stages of their manufacture 
should conform to be considered acceptable for its intended use.

6.0 Appendices

6.1 Appendix for Physicochemical Characterization

    This appendix provides examples of technical approaches which 
might be considered for structural characterization/confirmation and 
evaluation of physicochemical properties of the desired product. The 
specific technical approach employed will vary from product to 
product, and alternative approaches, other than those included in 
this appendix, will be appropriate in many cases. New analytical 
technology and modifications to existing technology are continuously 
being developed. Such technologies should be utilized when 
appropriate.

6.1.1 Structural characterization/confirmation

    (a) Amino acid sequence
    The amino acid sequence of the desired product should be 
determined to the extent possible using approaches such as those 
described in items (b) through (e) and then compared with the 
sequence of the amino acids deduced from the gene sequence of the 
desired product.
    (b) Amino acid composition
    The overall amino acid composition is determined using various 
hydrolytic and analytical procedures and compared with the amino 
acid composition deduced from the gene sequence for the desired 
protein, or the natural counterpart, if considered necessary, taking 
into account the size of the molecule. In many cases, amino acid 
composition analysis provides some useful structural information for 
peptides and small proteins, but such data are generally less 
definitive for large proteins. Quantitative amino acid analysis data 
can also be used to determine protein content in many cases.
    (c) Terminal amino acid sequence
    Terminal amino acid analysis is performed to identify the nature 
and homogeneity of the amino   (N-) and carboxy (C)-terminal amino 
acids. If the desired product is found to be heterogeneous with 
respect to the terminal amino acids, the relative amounts of the 
variant forms should be determined using an appropriate analytical 
procedure. The sequence of these terminal amino acids should be 
compared with the terminal amino acid sequence deduced from the gene 
sequence of the desired protein.
    (d) Peptide map
    Selective fragmentation of the product into discrete peptides is 
performed using suitable enzymes or chemicals, and the resulting 
peptide fragments are analyzed by HPLC or other appropriate 
analytical procedures. The peptide fragments should be identified to 
the extent possible using techniques such as amino acid 
compositional analysis, N-terminal sequencing, or mass spectrometry. 
Validated peptide mapping is frequently an appropriate method to 
confirm desired product structure/identity for lot release purposes.
    (e) Sulfhydryl group(s) and disulfide bridges
    If, based on the gene sequence for the desired protein, cysteine 
residues are expected, the number and positions of any free 
sulfhydryl groups and/or disulfide bridges should be determined, to 
the extent possible. Peptide mapping (under reducing and nonreducing 
conditions), mass spectrometry, or other appropriate techniques may 
be useful for this evaluation.
    (f) Carbohydrate structure
    For glycoproteins, the carbohydrate content (neutral sugars, 
amino sugars, and sialic acid) is determined. In addition, the 
structure of the carbohydrate chains, the oligosaccharide pattern 
(antennary profile), and the glycosylation site(s) of the 
polypeptide chain are analyzed, to the extent possible.

6.1.2 Physicochemical properties

    (a) Molecular weight/size
    Molecular weight (or size) is determined using size exclusion 
chromatography, SDS-polyacrylamide gel electrophoresis (under 
reducing and/or nonreducing conditions), mass spectrometry, and/or 
other appropriate techniques.
    (b) Isoform pattern
    This is determined by isoelectrical focusing or other 
appropriate techniques.
    (c) Extinction coefficient (or molar absorptivity)
    In many cases, it will be desirable to determine the extinction 
coefficient (or molar absorptivity) for the desired product at a 
particular UV/visible wavelength (e.g., 280 nanometers). The 
extinction coefficient is determined using UV/visible 
spectrophotometry on a solution having a known protein content as 
determined by techniques such as amino acids compositional analysis 
or nitrogen determination.
    (d) Electrophoretic patterns
    Electrophoretic patterns and data on identity, homogeneity, and 
purity of the desired product/drug substance obtained by 
polyacrylamide gel electrophoresis, isoelectric focusing, SDS-
polyacrylamide gel electrophoresis, Western-Blot, capillary 
electrophoresis, or other suitable procedures are determined as 
appropriate.
    (e) Liquid chromatographic patterns
    Chromatographic patterns and data on the identity, homogeneity, 
and purity of the desired product/drug substance obtained by size 
exclusion chromatography, reverse-phase liquid chromatography, ion-
exchange liquid chromatography, affinity chromatography, or other 
suitable procedures are determined as appropriate.
    (f) Spectroscopic profiles
    The ultraviolet and visible absorption spectra are determined as 
appropriate. The higher-order structure of the product is examined 
using procedures such as circular dichroism, nuclear magnetic 
resonance (NMR), or other suitable techniques as appropriate.

6.2 Appendix for Impurities

    This appendix lists potential impurities, their sources, and 
examples of relevant analytical approaches for detection. Specific 
impurities and technical approaches employed, as in the case of 
physicochemical characterization, will vary from product to product, 
and alternative approaches other than those listed in this appendix 
will be appropriate in many cases. New analytical technology and 
modifications to existing technology are continuously being 
developed. Such technologies should be utilized when appropriate.

6.2.1 Process-related impurities

    These are derived from the manufacturing process (section 2.1.4) 
and are classified into three major categories: Cell substrate-
derived, culture-derived, and downstream-derived.
    (a) Cell substrate-derived impurities include proteins/
polypeptides derived from the host organism; nucleic acid (host cell 
generic/vector/total DNA); polysaccharides; viruses. For host cell 
proteins, a sensitive immunoassay capable of detecting a wide range 
of protein impurities is generally utilized. The polyclonal antibody 
utilized in the test is generated from a crude preparation of a mock 
production organism, i.e., a production cell minus the product-
coding gene. The level of DNA from host cells can be detected by 
direct analyses on the product (such as hybridization techniques) 
and/or by spiking experiments (laboratory scale) demonstrating the 
removal of nucleic acid by the purification process. For 
intentionally introduced viruses, the ability of the manufacturing 
process to remove/inactivate viruses should be demonstrated as 
described in the ICH guidance Q5A ``Viral Safety Evaluation of 
Biotechnology Products Derived from Cell Lines of Human or Animal 
Origin.''

[[Page 31513]]

    (b) Culture-derived impurities include inducers 
(polynucleotides, viruses) antibiotics, serum, other media 
components.
    (c) Downstream-derived impurities include enzymes, chemical/
biochemical processing reagents (e.g., cyanogen bromide, guanidine, 
oxidizing and reducing agents), inorganic salts (e.g., heavy metals, 
arsenic, non metallic ion), solvents, carrier/ligands (e.g., 
monoclonal antibodies), other leachables.

6.2.2 Product-related impurities

    The following represents the most frequently encountered 
molecular variants of the desired product and lists relevant 
technology for their assessment:
    (a) Truncated forms. Cellular peptidases may catalyze the 
removal of amino acids or catalyze internal cleavages. This may be 
detected by HPLC or SDS-PAGE. Peptide mapping may be useful, 
depending on the property of the variant.
    (b) Deamidated, isomerized, mismatched S-S linked, oxidized 
forms may need considerable effort in isolation and characterization 
in order to identify the type of chemical modification(s) and amino 
acid residue(s) involved. Chromatographic and/or electrophoretic 
methods (e.g., HPLC, capillary electrophoresis, mass spectroscopy, 
circular dichroism) may be utilized to isolate and characterize such 
variants.
    (c) The category of aggregates includes dimers and higher 
multiples of the molecular entity. These are generally resolved from 
the active moiety and quantitated by size exclusion chromatography 
(e.g., SE-HPLC). Degradants identified from stability studies as 
being generated in significant amounts should be tested for and 
monitored against appropriately established acceptance criteria.

    Dated: June 2, 1998.
William K. Hubbard,
Associate Commissioner for Policy Coordination.
[FR Doc. 98-15193 Filed 6-8-98; 8:45 am]
BILLING CODE 4160-01-F