In-house CHO HCPs platform: A promising approach for HCPs ELISA monitoring

Abstract

A key aspect that must be supervised during the development of recombinant therapeutic products is the potential presence of impurities.Residual host cell proteins (HCPs) are a major class of process-related impurities derived from the host organism that even in trace amount have the potential to affect product quality, safety, and efficacy. Therefore, the product purification processes must be optimized to consistently remove as many HCPs as feasible, with the goal of making the product as pure as possible. The workhorse of HCP monitoring and quantitation during bioprocessing manufacturing is sandwich ELISA (enzyme‐linked immunosorbent assay), which employs polyclonal anti-HCP antibodies for both capture and detection. Commercial ELISA kits developed from Chinese Hamster Ovary (CHO) cell lines are widely applied in early drug development stages (preclinical, phase I, and phase II), but are not specifically designed for a given manufacturer's proprietary cell line, and users do not have control over reagent availability and lot-to-lot consistency. For later development stages, the upstream process-specific method is preferred to guarantee an improved sensitivity and coverage. In agreement with the USP General Chapter 〈1132〉, a platform assay can be used in place of the commercial one through all stages of product development, if already available when product development starts.This proof-of-concept study was carried out to demonstrate the feasibility and the advantages of the development of a proprietary CHO HCPs platform ELISA. Different proprietary mock materials have been characterized and compared by orthogonal bidimensional electrophoresis techniques (SDS-PAGE coupled to SS/WB and 2D DIGE) with the scope of selecting the best antigen-antibody couple for setting up the in-house ELISA. A preliminary evaluation of the in-house method performance has been done in comparison with the commercial assay, demonstrating that the platform method is promising for an accurate and precise CHO HCPs quantification during the early phase product and process development.