BIOLOGICAL AMENDMENTSrDNA-Produced Biopharmaceuticals

Southern African Regional and International Symposium1 – 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 Parameter Value Growth Rate (d-1) Percent Viability

pH 6.66.87.157.5

0.00.150.370.35

50758575

pO2 (mbar) 30100-150200

0.270.370.25

808580

pCO2 (mbar) 50-200250

0.370.0

8550

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– Doubling time– API concentration & Specific productivity– LDH activity at the end of fermentation– Viral safety & genetic stability of post-production cells of new

WCB

Potency & structural integrity of API (glycosylated)

Type A: Example 2• Optimisation of the isoform conversion process for the API• Cells in culture produce Isoform I → Isoform II → API

• 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

FermentationDownstream processing

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• 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.

ConclusionBiopharmaceutical 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.