HOST-CELL CONTAMINANT PROTEIN ASSAY DEVELOPMENT FOR RECOMBINANT BIOPHARMACEUTICALS

The efficiency and consistency of a biopharmaceutical purification pro cess determines drug quality, including which specific types and conce ntrations of residual host cell or process contaminants may remain. Co mmercial reagents and generic analytical methods are available for qua ntitating most of these contaminants. However, no generic assay is ava ilable for quantitation of the specific contaminant host cell proteins (HCPs) which are unique to a novel purification process. Because of t his, proprietary reagents and assays must be developed for the quantit ation of process-specific HCPs in each biopharmaceutical drug. The nee d to develop proprietary reagents which are both sensitive to, and spe cific for, potentially complex mixtures of unique contaminant proteins has defined what is acceptable methodology for development of quantit ative HCP assays. Within the biopharmaceutical industry this need is m ost often satisfied by the development of multi-analyte HCP immunoassa ys based upon the null cell mock purification model. Confidence in the quantitative nature of a given HCP assay, and the validity of analyti cal measurement obtained by the assay, is dependent upon empirical dem onstration of the unique stoichiometry of the HCP assay reagents. In c onjunction with other analytical and validation methods, an HCP immuno assay may be thought of as a necessary quantitative tool for the optim ization and validation of biopharmaceutical purification process effic iency and consistency, rather than as an end in itself.