(506a) Development of a Novel and Efficient Cell Culture Flocculation Process Using a Stimulus Responsive Polymer to Streamline Antibody Purification Processes

Recent advances in cell culture processes have significantly increased product titers with corresponding elevated levels of cell densities and cellular debris as well as process and product related impurities, necessitating improvements in downstream processing.  In this study we have developed an alternative antibody harvest process that includes flocculation using a novel stimulus responsive polymer, benzylated poly(allylamine), followed by depth filtration. The process demonstrates high process yield, improved clearance of cells and cell debris, and efficient reduction of aggregates, host cell proteins (HCP) and DNA for multiple antibodies.  A wide operating window has been established through design of experiments condition screening and optimization.  This process has achieved residual levels of impurities in the Protein A eluate that potentially meet the requirements of drug substance and thus alleviate the burdens for further impurities removal in the subsequent chromatography steps.  In addition, efficient clearance of residual polymer has been demonstrated using a florescence tagged polymer in the presence of a stimulus reagent.   This novel and efficient process can be easily integrated into current mAb purification platforms, and may improve current mAb purification processes by overcoming downstream processing challenges.