Host-cell proteins (HCPs) represent a major class of process-related impurities (PRIs) that are generated during biopharmaceutical manufacture. Although the vast majority of such proteins are removed from a drug substance during downstream purification, residual HCPs can remain in a finished drug product. Even in minimal concentrations, copurifying HCPs can pose safety risks and compromise protein-product yield, efficacy, and stability. Thus, regulatory agencies consider the presence of HCPs to be a critical quality attribute (CQA). Sufficient clearance of these impurities helps…