Explaining the Variability of Biologics and Biosimilars

Jim M. Koeller, MS, FHOPA, professor of pharmacotherapy and Eli Lilly/CRSublett Fellow in the College of Pharmacy, The University of Texas at Austin, and clinical professor of medicine and oncology, The University of Texas Health Science Center, discusses the inherent variability of recombinant DNA technology behind biosimilars.

Variability from post-translational modifications during replication can take place when making any biologic, says Koeller.

Also, variability when formulating a product can exist because biologics are not made through chemical synthesis like aspirin, Koeller continues. Instead, a monoclonal antibody in a solution is filtered repeatedly.

Though filtering removes larger impurities, small protein fragments and glycans can exist in the final product. From there, separation chromatography isolates the protein.

These batch differences may become biosimilars that are approved based on comparability standards set by the FDA, says Koeller.