jabbrv-ltwa-all.ldf jabbrv-ltwa-en.ldf The development of biosimilar monoclonal antibodies (mAbs) requires careful control of critical quality attributes and a thorough understanding of cell culture performance. This study focuses on the development and characterization of a biosimilar mAb targeting VEGFR-2 using Chinese Hamster Ovary (CHO) cells. Seventy-five clones were generated via gene transfection and screened for productivity and viability. Key upstream parameters such as culture pH, glucose levels, viability, and cell-specific productivity were monitored to assess their impact on product quality and yield. Eight high-performing clones were scaled up for further production. The biosimilar candidate was comprehensively characterized using intact mass spectrometry, peptide mapping, glycan profiling, size exclusion chromatography, hydrophobic interaction chromatography, cation exchange chromatography, and binding kinetics analysis. The top-producing clone achieved a titer of 2.79 g/L. Analytical results demonstrated strong structural and functional similarity to the reference product, with no critical deviations observed in purity, charge variants, glycosylation, or binding affinity. This work highlights the importance of integrated upstream process monitoring and rational clone selection in the development of high-quality biosimilars. The findings contribute to a deeper understanding of how cell behavior and process parameters influence biosimilar attributes, supporting both regulatory compliance and efficient process development.