Evaluation of Structural, Biological, and Functional Similarity of Biosimilar Granulocyte Colony Stimulating Factor to its Reference Product

Purpose Granulocyte colony stimulating factor (GCSF; also known as filgrastim) is a growth factor used to induce production of granulocytes. As the first locally developed and approved biosimilar medicine of Turkey, Fraven (R) being a biosimilar of filgrastim has been ab initio manufactured from cell to finished product at two different production facilities. Comprehensive structural, biological and functional characterization studies were performed to compare Fraven (R) from two different production sites and its reference product Neupogen (R) sourced from Turkey. Methods Primary and higher-order protein structures were analyzed by high performance liquid chromatography electrospray ionization-time of flight mass spectrometry, circular dichroism, and two-dimensional nuclear magnetic resonance spectroscopy. Isoelectric focusing, SDS-Page, size exclusion chromatography, and related proteins analyses were used to compare impurities. In order to assess functional similarity, surface plasmon resonance (SPR) was used.In vitrocell proliferation assay was also performed to show dose related drug response in NFS-60 cell line. Results Primary, secondary and tertiary structures of biosimilar Fraven (R) manufactured at both sites were found to be highly similar to the reference Neupogen (R). Product related substances and impurities were also highly similar to the reference. Comparability of GCSF receptor binding affinities of each product was shown using the K(D)values of SPR analysis.In vitrocell proliferation similarity was also evaluated and proven by PLA. Conclusion Based on the similarity assessment, despite being manufactured at two different production sites, biosimilar Fraven (R) is highly similar to the reference product Turkey originated Neupogen (R).