Assessing analytical comparability of Biosimilars: GCSF as a case study
Neh Nupur, Sumit Kumar Singh, Gunjan Narula, Anurag S. Rathore
Journal of Chromatography B
The biosimilar industry is witnessing an unprecedented growth with the newer therapeutics increasing in complexity over time. A key step towards development of a biosimilar is to establish analytical comparability with the innovator product, which would otherwise affect the safety/efficacy profile of the product. Choosing appropriate analytical tools that can fulfil this objective by qualitatively and/or quantitatively assessing the critical quality attributes (CQA) of the product is highly critical for establishing equivalence. These CQA cover the primary and higher order structures of the product, product related variants and impurities, as well as process related impurities, and host cell related impurities. In the present work, we use such an analytical platform for assessing analytical comparability of five approved Granulocyte Colony Stimulating Factor (GCSF) biosimilars (Emgrast, Lupifil, Colstim, Neukine and Grafeel) to the innovator product, Neupogen®. The comparability studies involve assessing structural homogeneity, identity, secondary structure, and product related modifications. Physicochemical analytical tools including peptide mapping with mass determination, circular dichroism (CD) spectroscopy, reverse phase chromatography (RPC) and size exclusion chromatography (SEC) have been used in this exercise. Bioactivity assessment included comparison of relative potency through in vitro cell proliferation assays. The results from extensive analytical examination offer robust evidence of structural and biological similarity of the products under consideration with the pertinent innovator product. For the most part, the biosimilar drugs were found to be comparable to the innovator drug. An anomaly that was identified was that three of the biosimilars had a conformational variant which has been reported as oxidized species in the literature. However, upon further investigation using RPC-FLD and ESI-MS we found that this is likely a tertiary variant of the biotherapeutic.
Circular dichroism, Secondary structure, Biochemistry