Comparing Culture Methods in Monoclonal Antibody Production Batch , Fed-Batch , and Perfusion

level: interMediate R ecombinant protein manufacturing with Chinese hamster ovary (CHO) cells represents over 70% of the entire biopharmaceutical industry (1). In fact, human monoclonal antibodies (hMAbs) produced by CHO cells have played a major role in both the diagnostic and therapeutic markets for decades. One of the first human– mouse chimeric MAbs to obtain FDA approval was Roche’s rituximab treatment for non-Hodgkin’s lymphoma, chronic lymphocytic leukemia, and rheumatoid arthritis. Since that approval in 1997, scores of chimeric, humanized, and human MAbs have gained approval and entered clinical use. More are coming in the future as many blockbuster MAb-based treatments reach the “patent cliff.” Indeed, process development and optimization are under way at many research and development (R&D) facilities as a number of companies race to develop biosimilars: highly similar copies of currently approved therapeutic hMAbs. In development of all pharmaceutical production processes, including those involving hMAbs produced by CHO cells, decisions regarding the best process parameters and methods are made based on cost, time, and titer comparisons. Often, multiple scalable platforms are examined before a final process is transferred to pilotor scale-up laboratories (2–8). Significant R&D time and dollars are invested to increase yields, reduce costs, and improve current bioreactor and bioprocess technologies (7). The objective of our research project was to compare the performance of batch, fed-batch, and perfusion processes — the three primary methods for hMAb production — using a single, laboratory-scale bioprocess controller. In the batch method, all nutrients are supplied in an initial base medium. The fed-batch method adds nutrients once they are depleted. The perfusion method circulates medium through a growing culture, allowing simultaneous removal of waste, supply of nutrients, and harvesting of product. We compared two perfusion processes that differed in the way that cells are retained in a bioreactor. In one setup, we used an alternating tangential-flow (ATF) filtration device, which uses hollow-fiber filters to retain cells. In the second setup, we cultivated cells in a packedbed bioreactor in which they were immobilized on a solid support matrix.