Characterization and optimization of a CHO antibody manufacturing process

The use of monoclonal antibodies (mAbs) as biotherapeutics has shown an increasing trend in recent years. This growing demand for mAb applications is expected to continue, challenging current manufacturing practices to improve cost efficiency and production capacity. This study focuses on two interdependent aspects of manufacturing: the selection of clones and the production process itself, aiming to enhance cost-efficiency and production capacity (Chapter 1). Chapter 2 analyzes cell clones in both state-of-the-art processes (fed-batch (FB) and steady-state perfusion) to identify advantageous characteristics. Results showed that both production formats were significantly impacted by the cellular volume of the clones. In the FB process, cell volume-specific productivity had a critical impact on overall productivity, while clones with constant cell volume showed superior performance in steady-state perfusion. Including cell volume in production performance criteria could benefit cell line transfer and clone selection. Chapter 3 examines process-related impurity levels, mainly the accumulation of host-cell protein (HCP) for different cell clones. The chapter revealed significant intracellular protein release into the cell culture supernatant. Moreover, cell volume had a major impact, affecting the HCP quantity from different compartments. The chapter further provides insight into the origin of HCP release and differences between cell clones. Chapter 4 introduces an intensified process scenario based on a mid-process media exchange step (IH), further enhancing the discontinuous fed-batch processing. The process resulted in increased cell count and enhanced cell-specific productivities, contributing to a 150% increase in productivity compared to the standard FB process. Chapter 5 explores combining the IH concept with an existing intensification method, a high inoculation FB (HiFB) approach. A proof-of-concept run confirmed the synergistic potential of these two intensifications, resulting in a threefold increase in STY compared to the standard FB. In Chapter 6, a semi-continuous concept was designed, the continuous fed-batch (cFB), combining short-term fed-batch with fast media exchange via the IH method and cell density adjustment in a repetitive manner. The intensified process could show enhanced productivity (+217%) compared to FB and decreases media consumption (-50%) in contrast to an steady-state perfusion. The general discussion in Chapter 7 further examines the main outputs of this thesis for each chapter. Cellular volume was identified as a critical parameter influencing efficiency, robustness, and overall performance of the manufacturing process. Moreover, developments in cell selection, such as miniaturized screening tools, were discussed, and further host cell engineering targets were examined. To enhance insight into the developed process intensification, an upstream cost-benefit analysis was conducted, showing advantages and drawbacks for both standard processes (FB and perfusion) and intensified processes. Additionally, the extension of the novel IH method to cell and gene therapy applications was discussed, addressing current limitations within these fields. Overall, this study provides novel insights into cellular characteristics and develops novel intensification methods to tackle key challenges in current biotherapeutic manufacturing.