Development and preliminary physicochemical characterization of a Ramucirumab biosimilar candidate in CHO cells using shake-flask fed-batch culture

The development of biosimilar monoclonal antibodies requires strict control of critical quality attributes and a detailed understanding of cell culture performance. This study describes the development and preliminary physicochemical characterization of a candidate biosimilar monoclonal antibody targeting VEGFR-2 produced in CHO cells. Seventy-five clones generated through gene transfection were screened based on productivity and cell viability. Culture parameters including pH, glucose concentration, cell growth, and cell specific productivity (Qp) were monitored to evaluate their influence on production performance. Eight high producing clones were selected for shake-flask scale fed-batch production. The lead clone achieved a final titer of 2.79 g/L. The biosimilar candidates were characterized using intact mass spectrometry, size exclusion chromatography, cation exchange chromatography, hydrophobic interaction chromatography, glycan analysis, and peptide mapping. Binding affinities were evaluated using SPR, demonstrating comparable interaction with VEGFR-2. The analytical results demonstrated structural similarity to the reference product with no critical differences in purity, charge variants, glycosylation patterns, or binding affinity. These findings demonstrate the importance of systematic clone screening and upstream process monitoring for achieving consistent product quality in biosimilar antibody production and provide practical insights for mammalian cell-based bioprocess development.