CHALLENGES FACED IN THE DEVELOPMENT OF BIOSIMILARS Dr.G.Hima Bindu MD; PG dip. diabetology Asst.Professor Dept. of Pharmacology Rajiv Gandhi Institute of Medical Sciences Ongole

 Biologics  Differences  Manufacturing process  Challenges in the development

INTRODUCTION Biologics derived from living cells Currently used in  Blood conditions : leuco/neutro/pancytopenia  Cancer: colon, breast, non Hodgkins lymphoma  Immune system disorders: RA, psoriasis  Neurological: multiple sclerosis World wide, nearly 200 biologics saved over 800 million patients

Need for biosimilars Increasing demand for biologics  Patent expiry  Takes more time and cost to develop Alternate version of innovator biopharmceuticals – Similar biotherapeutic products : WHO – Biosimilars : Europe – Follow – on – biologics : US

5 Biosimilars are similar……. …. Not Identical WHO: “A biotherapeutic product similar in terms of quality, safety and efficacy to an already licensed reference biotherapeutic product.” Similarity must be shown on the basis of the analytical, non clinical and clinical data

DIFFERENCES

7 Chemical drugsBiologics Small, simple molecule (mol. Wt Da) with defined structure Large complex molecules (mol.wt Da), Heterogenous structure Made by chemical synthesis Made by living cells Easy to characterizeDifficult to characterize Easy to purifyLengthy and complex purification process

Contamination avoided, easily detectable & removable High possibility of contamination. Detection is harder Relatively stable Variable, sensitive to environmental conditions Administered by various routes Parenteral Non immunogenicImmunogenic Chemical drugsBiologics

MANUFACTURING PROCESS

Manufacturing Process Complex process Developed through sequential process Systematically engineered to match the reference product

Major steps involved in the manufacture Gene selection Insertion into vector Cell culture Protein productionPurification Formulation

CHALLENGES

Cell line generation Protein production Protein purification

Microbial cells, cell lines of human or animal origin or tissues derived from animals or plants are used. Bacteria & yeast cell lines require minimal growth media conditions and are fast growing.  Traditional cell lines are prone to host cell protein contamination Cell Line Generation

Cont… Chinese Hamster ovary (CHO) cells are preferred mammalian cell line If the host cell line used for production of reference product is known same cell line is used.  The expression system can have a significant effect on the types and extent of translational and post translational modifications.

Every manufacturer uses unique cell line and proprietary process. So it is difficult to produce biosimilars that are identical to the original drug. Cont….

Protein Production Structure of protein is heterogeneous - exhibit complex three dimensional conformations.  The structure – function relationships are very sensitive as modifications of may affect safety, purity and/ or potency.  ELISA and size exclusion chromatography are used

 The function of a protein can be altered by Replication errors in the DNA encoding protein sequence Amino acid misincorporation during translation Post translational modifications Cont….

Protein PhosphorylationGlycosylation Lipid attachmentProteolytic cleavage Increase half life Membrane stability Activation or inhibition Activation Post translational modifications

 Changes in protein modification may reduce biological activity  These post translational modifications are affected by the cell line.  Glycosylation is sensitive to cell growth conditions  changes in culture pH  the availability of precursors and nutrients  presence or absence of various cytokines and hormones. Cont….

 It is difficult to characterize glycosylation pattern or the higher order/ 3D structure.. Tools to detect:  SDS-PAGE  RP-HPLC  Size exclusion chromatography  Mass spectroscopy Cont….

Protein Purification  Oxidation/deamidation or even protein aggregation can occur during the process.  Protein molecules can also be degraded and impurities created Additives used to stabilize proteins: – human serum albumin (HSA), – polysorbates, – calcium chloride

Immunogenicity All therapeutic proteins induce some antibody response. Various factors influence immunogenicity patient related characteristics  Product related factors

Molecule design Cell line Deglycosylation Exposure of antigenic sites Misfolding/ aggregation Impurities Product related factors

The increasing demand for more cost effective treatment and patent expiry of biologics created growing market for biosimilars. It is difficult to develop biosimilars identical to original drug. Use of different vector Diff. Cell expression system Diff. in growth media, nutrients Diff. operating methods, reagents, reference products SUMMARY