# Is Your HCP Assay Fit for Purpose?

Removal of host cell protein (HCP) impurities in drug substances is critical in the manufacture of highquality drug products and for patient safety. A key requirement is a thorough analysis of HCP contaminants, which may vary considerably depending on cell line, media, and process parameters. How well a particular HCP assay recognizes all HCPs will depend on how well its antibodies match the actual HCP composition, their abundance, and affinities for each HCP. Accordingly, various commercial generic HCP ELISAs may differ substantially in their ability to detect similar types and levels of HCPs.

Platform or specific HCP assays offer peace of mind. However, because of the high risk of drug failure, such assays are a worthwhile investment only in later stages of development.