BIOLOGICAL AMENDMENTS
rDNA-Produced Biopharmaceuticals
Southern African Regional and International Symposium
1 – 3 August 2011
CSIR International Convention Centre, Pretoria
Henry M. J. Leng Ph.D, MBA
Introduction
Amendments to the registration dossier are
necessary to:
– maintain the safety, quality and efficacy of a
medicine,
– to ensure compliance with current technical
requirements,
– to adhere to administrative aspects,
– to keep abreast of scientific progress, or
– to reflect new therapeutic indications/warnings
or other safety matters.
Definition
• Additions, deletions or changes to the
product application dossier that reflect
either administrative changes with respect
to the holder of the registration certificate
or technical changes to the product which
result in the product having the same (or
better) quality and clinical performance as
the originally registered product.
Classification of Amendments
• Type A: Unlikely to affect the quality and
performance of a product.
– Do not require prior approval or notification
before implementation
• Type B: Could have a significant impact on
the quality and performance of a product.
– Written notification of the type of amendment
should be forwarded to the MCC 30 days prior
to intended implementation date.
Classification of Amendments
(cont.)
• Type C: Highly likely to have a significant
impact on the quality and performance of a
product.
– Written approval from the MCC should be
obtained before the change may be
implemented.
• Type D: Amendments that should be
considered new applications
Properties of Biopharmaceuticals
• A biopharmaceutical is a
biological medicinal
product developed by
means of the following
biotechnology practices:
– rDNA technology, controlled
gene expression, hybridoma or
other antibody methods.
– They include Biosimilars
– Varying sizes and complexity
Molecular weights
Complex Structural Characteristics
Multiple Post-Translational
Modifications
The Biotechnology Manufacturing Process is
Complex, Using Living Organisms, and is
Critical to the Final Structure of the Product
Physicochemical Stability
Degradation
• Includes:
–
–
–
–
–
Hydrolysis
Oxidation
Racemisation
β-Elimination
Disulfide exchange
• Most, except, disulfide
exchange leads to bond
cleavage → product
related impurities
Denaturation
• Extremes in pH, Tº, ionic
strength, organic solvents.
• Decreases aqueous
solubility
• Alter 3D-shape
• ↑ susceptibility to
enzymatic breakdown
• Loss of activity
• Adsorption to surfaces (vial
walls)
• Non-covalent self-aggregation
• Proteins form aggregates
which precipitate out of
solution resulting in a loss
of activity
Influence of pH, pO2, pCO2 on
Cell Growth
Parameter
Growth Rate (d-1)
Parameter Value
Percent Viability
pH
6.6
6.8
7.15
7.5
0.0
0.15
0.37
0.35
50
75
85
75
pO2 (mbar)
30
100-150
200
0.27
0.37
0.25
80
85
80
pCO2 (mbar)
50-200
250
0.37
0.0
85
50
Relevance of Current Amendment
Guideline
• Based on our knowledge of the complexity of the
structure, manufacture and formulation
requirements of biopharmaceuticals, is the current
Amendment Guideline still appropriate?
• Should we still permit Type A and Type B
amendments that affect aspects of the
manufacturing, purification and formulation of
products derived from recombinant DNA
technology?
Type A: Example 1
•
•
•
•
•
•
•
Implementation of a new cell bank system and definition of a new maximum
cell age for the API cultivation process.
MCB was produced with FCS as source of growth factors.
WCB was adapted to grow in absence of FCS.
New WCB needs to be established because of diminishing stock.
Applicant proposes to use remaining stock of current FCS-free WCB as new
MCB from which a new WCB will be established.
Motivation: Avoid repeated adaptation of current MCB to serum-free
conditions.
Requirements: Comparative characterisation of WCBs
– Viable cell density & Viability
Potency &
structural integrity
– Doubling time
of API
– API concentration & Specific productivity
(glycosylated)
– LDH activity at the end of fermentation
– Viral safety & genetic stability of post-production cells of new
WCB
Type A: Example 2
• Optimisation of the isoform conversion process for the API
• Cells in culture produce Isoform I → Isoform II → API
Fermentation
Downstream
processing
• Previous amendment (Type A) applicant switch to a new nutrient
starting material from same supplier but of lower ash content.
• New batches had higher isoform levels and lower API yield due to
reduced conversion of isoforms to API.
• Original nutrient medium was unavailable so applicant had to
introduce additional process hold step to promote conversion.
•
•
•
Supporting data: Process validation study with 3 batches to verify maintenance
of critical quality attributes
API characterisation study (physicochemical, biological, purity testing) and
compared with current release criteria
API and product stability studies
Type B Amendment
• Scale-up from 1000 L to 5000 L (intermediate glycosylated protein)
– Highly automated
– Use of an additional 10 L pre-cultivation bioreactor to replace spinner
flasks
– Added a nano-filtration step as additional purification for greater viral
safety.
– Scale-up of the RP-HPLC for purification.
Supporting data: Comparability studies using 12 batches
•
•
•
•
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Routine in-process control testing to show process consistency.
Removal of impurities for process removal capability.
Release testing for all batches on the basis of the approved release specification for 1K
batch size.
Side-by-side analysis (SDS-PAGE, LysC peptide mapping, RP-HPLC and SE-HPLC)
Extended characterisation (site-specific glycosylation pattern, CD spectroscopy for
higher order structural analysis)
Stability profiles at real time and accelerated conditions.
Comparative pharmacokinetic profiles????
Additional Requirements
• Improvements, upscaling and other modifications in the manufacture
of biopharmaceutical
• Amendments frequently occur as manufacturers gain experience or
due to new regulatory requirements.
• In spite of adequate supporting data submitted by applicants, concerns
about long term safety do still remain.
• For example, when human serum albumin was replaced in a
erythrpoetin product in Europe with polysorbate 80 and glycine, and
upsurge in cases of PRCA occurred.
• The extensive changes engineered to the production of some products,
sometimes to the extent that a totally new DMF is submitted, has
compelled the MCC to add as condition for approval, the submission of
PSURs.
• Local applicants must conduct pharmacovigilance in the SA market.
Conclusion
Biopharmaceutical medicines are complex preparations by virtue
of the unique physical, chemical and structural properties of the
API’s they contain.
A change to the manufacturing, purification and formulation
processes may impact the quality and safety of these products in a
manner that cannot always be predicted by comparative analytical
studies.
Classification of such changes as Type A or B amendments are,
therefore, not appropriate.
The approval of major amendments with additional requirements,
such as the submission of 6-monthly or annual PSURs, may thus be
justified.
Proposal
• Development of an amendment guideline,
specific to biological products, with a
classification system based on current
knowledge and understanding of the
complex nature of API’s produced by
recombinant DNA, hybridoma and other
molecular biology techniques.