BIOT 1 In silico design of integrated downstream processes for non-mAb biologics produced in complex expression systems Nicholas Vecchiarello2,
[email protected], Chaz Goodwine3, Steven M. Cramer1. (1) Ricketts Bldg, Rensselaer Polytechnic Inst, Troy, New York, United States (2) Rensselaer Polytechnic Institute, Troy, New York, United States (3) Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York, United States For biomolecules not amenable to affinity capture, determining optimal downstream processes can be a major challenge due to the broad range of experimental design space available with regard to resins, buffer pH, and salt. Previous work in our group has addressed this issue for products produced in Pichia pastoris by chromatographically characterizing process-related impurities found in spent cultivation fluids on a set of multimodal, HCIC, and ion exchange resins for a wide range of conditions using UP-RPLC. The collected data was used in concert with product retention data and a custom in silico tool to generate and rank integrated downstream processes for three non-monoclonal antibody products expressed in P. pastoris. In this work, we have chromatographically characterized the host-related impurity behavior for a CHO cell line containing a more significant HCP burden. In an effort to expedite process development, a method for assessing global orthogonal selectivity for different process-related impurities between resin pairs was employed in order to prune the number of resins required for screening. This strategy was then applied to the purification of a product with a significant variant challenge. To further reduce the number of resins to screen for product retention, sequence understanding and biophysical properties were utilized to focus on regions that would likely remove host- related impurities and offer variant selectivity.