[Federal Register Volume 60, Number 161 (Monday, August 21, 1995)]
[Notices]
[Pages 43496-43498]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-20611]




[[Page 43495]]

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Part II





Department of Health and Human Services





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Food and Drug Administration



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Harmonisation International Conference; Guidelines Availability; 
Notices

  Federal Register / Vol. 60, No. 161 / Monday, August 21, 1995 / 
Notices   

[[Page 43496]]


DEPARTMENT OF HEALTH AND HUMAN SERVICES

Food and Drug Administration
[Docket No. 95D-0216]


International Conference on Harmonisation; Draft Guideline on 
Analysis of the Expression Construct in Cells Used for the Production 
of r-DNA Derived Protein Products; Availability

AGENCY: Food and Drug Administration, HHS.

ACTION: Notice.

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SUMMARY: The Food and Drug Administration (FDA) is publishing a draft 
guideline entitled ``Analysis of the Expression Construct in Cells Used 
for Production of r-DNA Derived Protein Products.'' This guideline was 
prepared under the auspices of the International Conference on 
Harmonisation of Technical Requirements for Registration of 
Pharmaceuticals for Human Use (ICH). The draft guideline is intended to 
describe the types of information that are considered valuable in 
assessing the structure of the expression construct used to produce 
recombinant deoxyribonucleic acid (r-DNA) derived proteins.

DATES: Written comments by October 5, 1995.

ADDRESSES: Submit written comments on the draft guideline to the 
Dockets Management Branch (HFA-305), Food and Drug Administration, rm. 
1-23, 12420 Parklawn Dr., Rockville, MD 20857. Copies of the draft 
guideline are available from the CDER Executive Secretariat Staff (HFD-
8), Center for Drug Evaluation and Research, Food and Drug 
Administration, 7500 Standish Pl., Rockville, MD 20855, as well as the 
CBER Congressional and Consumer Affairs Branch (HFM-12), Center for 
Biologics Evaluation and Research, Food and Drug Administration, 1401 
Rockville Pike, Rockville, MD 20852.

FOR FURTHER INFORMATION CONTACT:
    Regarding the guideline: Kenneth Seamon, 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.
    At a meeting held on March 28, 1995, the ICH Steering Committee 
agreed that a draft guideline entitled ``Analysis of the Expression 
Construct in Cells Used for Production of r-DNA Derived Protein 
Products'' should be made available for public comment. The draft 
guideline is the product of the Quality Expert Working Group of the 
ICH. Comments about this draft will be considered by FDA and the Expert 
Working Group. Ultimately, FDA intends to adopt the ICH Steering 
Committee's final guideline.
    This draft guideline presents guidance regarding the 
characterization of the expression construct for the production of r-
DNA protein products in eukaryotic and prokaryotic cells. The draft 
guideline is intended to describe the types of information that are 
considered valuable in assessing the structure of the expression 
construct used to produce recombinant DNA derived proteins. The draft 
guideline is not intended to cover the whole quality aspect of r-DNA-
derived medicinal products.
    In the past, guidelines have generally been issued under 
Sec. 10.90(b) (21 CFR 10.90(b)), which provides for the use of 
guidelines to state procedures or standards of general applicability 
that are not legal requirements but are acceptable to FDA. The agency 
is now in the process of revising Sec. 10.90(b). Therefore, this 
guideline is not being issued under the authority of Sec. 10.90(b), and 
it does not create or confer any rights, privileges, or benefits for or 
on any person, nor does it operate to bind FDA in any way.
    Interested persons may, on or before October 5, 1995, submit to the 
Dockets Management Branch (address above) written comments on the draft 
guideline. 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 guideline and received comments may be seen in the office above 
between 9 a.m. and 4 p.m., Monday through Friday.
    The text of the draft guideline follows:

Analysis of the Expression Construct in Cells Used for Production of r-
DNA Derived Protein Products

I. Introduction

    This document presents guidance regarding the characterization 
of the expression construct for the production of recombinant DNA 
protein products in eukaryotic and prokaryotic cells. This document 
is intended to describe the types of information that are considered 
valuable in assessing the structure of the expression construct used 
to produce recombinant DNA derived proteins. This document is not 
intended to cover the whole quality aspect of r-DNA derived 
medicinal products.
    The expression construct is defined as the expression vector 
containing the coding sequence of the recombinant protein. Segments 
of the expression construct should be analyzed using nucleic acid 
techniques in conjunction with other tests performed on the purified 
recombinant protein for assuring the quality and consistency of the 
final product. Analysis of the expression construct at the nucleic 
acid level should be considered as part of the overall evaluation of 
quality, taking into account that this testing only evaluates the 
coding sequence of a recombinant gene and not the translational 
fidelity nor other characteristics of the recombinant protein, such 
as secondary structure, tertiary structure, and post-translational 
modifications.

II. Rationale for Analysis of the Expression Construct

    The purpose of analyzing the expression construct is to 
establish that the correct 

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coding sequence of the product has been incorporated into the host cell 
and is maintained during culture to the end of production. The 
genetic sequence of recombinant proteins produced in living cells 
can undergo mutations that could alter the properties of the protein 
with potential adverse consequences to patients. No single 
experimental approach can be expected to detect all possible 
modifications to a protein. Protein analytical techniques can be 
used to assess the amino acid sequence of the protein and structural 
features of the expressed protein due to post-translational 
modifications such as proteolytic processing, glycosylation, 
phosphorylation, and acetylation. Data from nucleic acid analysis 
may be useful since protein analytical methods may not detect all 
changes in protein structure resulting from mutations in the 
sequence coding for the recombinant protein. The relative importance 
of nucleic acid analysis and protein analysis will vary from product 
to product.
    Nucleic acid analysis can be used to verify the coding sequence 
and the physical state of the expression construct. The nucleic acid 
analysis is performed to ensure that the expressed protein will have 
the correct amino acid sequence but is not intended to detect low 
levels of variant sequences. Where the production cells have 
multiple integrated copies of the expression construct, not all of 
which may be transcriptionally active, examination of the 
transcription product itself by analysis of mRNA or cDNA may be more 
appropriate than analysis of genomic DNA. Analytical approaches that 
examine a bulk population of nucleic acids, such as those performed 
on pooled clones or material amplified by the polymerase chain 
reaction, may be considered as an alternative to approaches that 
depend on selection of individual DNA clones. Other techniques could 
be considered that allow for rapid and sensitive confirmation of the 
sequence coding for the recombinant protein in the expression 
construct.
    The following sections describe information that should be 
supplied regarding the characterization of the expression construct 
during the development and validation of the production system. 
Analytical methodologies should be validated for the intended 
purpose of confirmation of sequence. The validation documentation 
should at a minimum include estimates of the limits of detection for 
variant sequences. This should be performed for either nucleic acid 
or protein sequencing methods. The philosophy and recommendations 
for analysis expressed in this document should be periodically 
reviewed to take advantage of new advances in technology and 
scientific information.

III. Characterization of the Expression System

A. Expression Construct and Cell Clone Used to Develop the Master Cell 
Bank (MCB)

    The manufacturer should describe the origin of the nucleotide 
sequence coding for the protein. This should include identification 
and source of the cell from which the nucleotide sequence was 
originally obtained. Methods used to prepare the DNA coding for the 
protein should be described.
    The steps in the assembly of the expression construct should be 
described in detail. This description should include the source and 
function of the component parts of the expression construct, e.g., 
origins of replication, antibiotic resistance genes, promoters, 
enhancers, whether or not the protein is being synthesized as a 
fusion protein. A detailed component map and a complete annotated 
sequence of the plasmid should be given, indicating those regions 
that have been sequenced during the construction and those taken 
from the literature. Other expressed proteins encoded by the plasmid 
should be indicated. The nucleotide sequence of the coding region of 
the gene of interest and associated flanking regions that are 
inserted into the vector, up to and including the junctions of 
insertion, should be determined by DNA sequencing of the construct.
    A description of the method of transfer of the expression 
construct into the host cell should be provided. In addition, 
methods used to amplify the expression construct and criteria used 
to select the cell clone for production should be described in 
detail.

B. Cell Bank System

    Production of the recombinant protein should be based on well-
defined Master and Working Cell Banks. A cell bank is a collection 
of ampoules of uniform composition stored under defined conditions 
each containing an aliquot of a single pool of cells. The Master 
Cell Bank (MCB) is generally derived from the selected cell clone 
containing the expression construct. The Working Cell Bank (WCB) is 
derived by expansion of one or more ampoules of the MCB. The cell 
line history and production of the cell banks should be described in 
detail including methods and reagents used during culture, in-vitro 
cell age, and storage conditions. All cell banks should be 
characterized for relevant phenotypic and genotypic markers which 
could include the expression of the recombinant protein or presence 
of the expression construct.
    The expression construct in the MCB should be analyzed as 
described below. If the testing cannot be carried out on the MCB, it 
should be carried out on each WCB.
     Restriction endonuclease mapping or other suitable techniques 
should be used to analyze the expression construct for copy number, 
for insertions or deletions, and for the number of integration 
sites. For extrachromosomal expression systems, the percent of host 
cells retaining the expression construct should be determined.
    The protein coding sequence for the recombinant protein product 
of the expression construct should be verified. For extrachromosomal 
expression systems, the expression construct should be isolated and 
the nucleotide sequence encoding the product should be verified 
without further cloning. For cells with chromosomal copies of the 
expression construct, the nucleotide sequence encoding the product 
could be verified by recloning and sequencing of chromosomal copies. 
Alternatively, the nucleic acid sequence encoding the product could 
be verified by techniques such as sequencing of pooled cDNA clones 
or material amplified by the polymerase chain reaction. The nucleic 
acid sequence should be identical, within the limits of detection of 
the methodology, to that determined for the expression construct as 
described in Section III.A. and should correspond to that expected 
for the protein sequence.

C. Limit for In-Vitro Cell Age for Production

    The limit for in-vitro cell age for production should be based 
on data derived from production cells expanded under pilot or full 
scale conditions to the proposed in-vitro cell age or beyond. 
Generally, the production cells are obtained by expansion of the 
Working Cell Bank; the Master Cell Bank could be used to prepare the 
production cells with appropriate justification.
    The expression construct of the production cells should be 
analyzed once for the MCB as described in Section III.B., except 
that the protein coding sequence of the expression construct in the 
production cells could be verified by either nucleic acid testing or 
analysis of the final protein product. Increases in the defined 
limit for in-vitro cell age for production should be supported by 
data from cells which have been expanded to an in-vitro cell age 
which is equal to or greater than the new limit for in-vitro cell 
age.

IV. Conclusion

    The characterization of the expression construct and the final 
purified protein are both important to ensure the consistent 
production of a recombinant DNA derived product. As described above, 
it is considered that analytical data derived from both nucleic acid 
analysis and evaluation of the final purified protein are necessary 
to ensure the quality of a recombinant protein product.

Glossary of Terms

Expression Construct

     The expression vector that contains the coding sequence of the 
recombinant protein and the elements necessary for its expression.

Flanking Control Regions

    Noncoding nucleotide sequences that are adjacent to the 5' and 
3' end of the coding sequence of the product which contain important 
elements that affect the transcription, translation, or stability of 
the coding sequence. These regions include, e.g., promoter, 
enhancer, and splicing sequences and do not include origins of 
replication and antibiotic resistance genes.

Integration Site

    The site where one or more copies of the expression construct is 
integrated into the host cell genome.

In-vitro Cell Age

    Measure of time between thaw of the MCB vial(s) to harvest of 
the production vessel measured by elapsed chronological time in 
culture, by population doubling level of the cells, or by passage 
level of the cells when subcultivated by a defined procedure for 
dilution of the culture.

Master Cell Bank (MCB)

     An aliquot of a single pool of cells which generally has been 
prepared from the selected cell clone under defined conditions, 

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dispensed into multiple containers, and stored under defined 
conditions. The MCB is used to derive all working cell banks. The 
testing performed on a new MCB (from a previous initial cell clone, 
MCB or WCB) should be the same as for the MCB, unless justified.

Pilot Plant Scale

     The production of a recombinant protein by a procedure fully 
representative of and simulating that to be applied on a full 
commercial manufacturing scale. The methods of cell expansion, 
harvest, and product purification should be identical except for the 
scale of production.

Relevant Genotypic and Phenotypic Markers

    Those markers permitting the identification of the strain or the 
cell line which should include the expression of the recombinant 
protein or presence of the expression construct.

Working Cell Bank (WCB)

    The Working Cell Bank is prepared from aliquots of a homogeneous 
suspension of cells obtained from culturing the MCB under defined 
culture conditions.

    Dated: August 14, 1995.
William K. Hubbard,
Acting Deputy Commissioner for Policy.
[FR Doc. 95-20611 Filed 8-18-95; 8:45 am]
BILLING CODE 4160-01-F