A fed-batch process for the production of biosimilar monoclonal antibody was developed. Since the brand product is produced by perfusion process, the impact of process change from perfusion to fed-batch on product quality and cell performance was evaluated. Perfusion culture was performed at 0.47-1.00 (v/v/d) perfusion rate by spin-filter method with 15-17 mu m mesh. Culture parameters such as pH (6.8-7.2), dissolved oxygen (40-70% air saturation), temperature (37 degrees C) and agitation speed (250 rpm) were applied in both culture modes. In terms of cell performance, volumetric productivity increased 3.7 times while process performance increased 7.5 times in fed-batch culture due to 10 times higher scalability. Considering the glycosylation pattern and charge variants, no significant changes in product quality were observed upon process change, although intact IgG level slightly decreased in fed-batch mode. The change of production media showed more effect on glycosylation patterns than the operation in different culture modes. Furthermore, there were no differences in biological activity, including TNF alpha, Fc gamma RIIIa, and C1q-binding affinity. Through a scale-up study from 3 L to 12,500 L, it was confirmed that cell performance and product quality could be maintained. In conclusion, product quality of the fed-batch process was comparable to that of the reference product. (C) 2012 Elsevier Ltd. All rights reserved.