In silico mediated development of orthogonally selective mAb downstream processes for the removal of process‐related impurities

Continued advancements in recombinant CHO expression of therapeutic mAbs have led to improved productivity but have also increased the HCP burden on the downstream purification process. In this work, we developed an in silico mediated workflow to facilitate the rapid development of non-protein A three-step processes for the effective removal of HCPs from a CHO-derived mAb therapeutic. Null CCF and pure mAb retention patterns were generated using linear gradient screens on a set of strategically selected resins, membrane adsorbers, and novel adsorbents. HCP characterization of key fractions was then carried out using RPLC "HCP fingerprinting" and the resulting retention database was processed using an in silico tool to generate a list of all possible three-step sequences subject to design constraints. Top-ranked processes generated by the tool were then evaluated and refined at the bench scale to produce several successful processes consisting of bind-elute capture followed by either a bind-elute and flowthrough step (91.4 ppm HCP with a cumulative product yield of 78.7%) or two flowthrough steps with no salt (96.1 ppm HCP with a cumulative yield of 81.4%).