(207b) Strategies for Mitigation and Control of PS80 Degradation in a Monoclonal Antibody Downstream Process

Polysorbates (PS), including PS80, are surfactants commonly used in the biopharmaceutical industry to prevent adsorption, aggregation, and/or particulate formation in monoclonal antibody (mAb) formulations. In recent years, cell culture process intensification and extensive process development activities have led to PS80 degradation challenges, attributed to the enzymatic activity of trace levels of residual host cell proteins (HCPs). Upon long-term storage of formulated mAb drug substance (DS) at ambient temperature, hydrolysis of PS80, catalyzed by these low levels of residual HCPs, can lead to precipitation and formation of undesired sub-visible and visible particulates, and thus, impact the drug product (DP) manufacturing and product control strategy. One approach to address these risks is to establish an integrated mitigation and control strategy for PS80 degradation in the DS downstream process. This work focuses on mitigating and controlling PS80 degradation through various unit operations in DS downstream process development to support technology transfer from bench-scale to clinical/commercial manufacturing facilities and to maintain formulated mAb stability throughout its shelf life. Specifically, we sought opportunities to mitigate the risk of PS80 degradation by evaluating the ability of Protein A chromatography and depth filtration post virus inactivation (VI) to clear HCPs during the processing of a mAb. Furthermore, we identified that process hold times at various temperatures prior to freezing DS could lead to consistently below-target DS PS80 concentration. This below-target PS80 concentration coupled with PS80 degradation could pose significant product risk. For this reason, a DS PS80 degradation study was conducted at cold (2 – 8 ºC) and room (25 ºC) temperatures to determine PS80 degradation rate and appropriate hold times during DS manufacturing. As a result, minimal PS80 degradation was observed at cold temperature over the time course of the study. The implementation of in-process hold time limits and temperature control in DS manufacturing has successfully resulted in an on-target PS80 concentration value in formulated mAb DS. Ultimately, the DS PS80 degradation mitigation and control strategies outlined in this work can significantly reduce the risk of particulates formation, and therefore, ensure product stability and consistency across all manufacturing batches.