Vailidation of immunoassays for anti-drug antibodies.

Several methods for the detection of an antibody response to a protein therapeutic are described along with their limitations. Emphasis is placed on immunoassays with specific attention to the ELISA format. Potential sources of interference and issues to consider in the design of an anti-drug antibody assay are reviewed. Establishment of criteria for validation of an anti-drug assay are discussed including inter-assay and intra-assay precision for the positive and negative controls, limit of detection, incidence of false positives, reactivity in unexposed populations, linearity of dilution, and interference issues. Finally, a case study involving the development of an anti-host cell protein contaminant assay involving responses to Chinese hamster ovary (CHO) cell contaminants is reviewed. Detection of an immune response to a biotherapeutic is critical to an understanding of its' safety and efficacy. Outlined in this paper are standard parameters for validation of an immunoassay as well as practical considerations for the development and validation of an anti-protein antibody assay.