Feasibility of a direct binding electrochemiluminescence assay to detect anti-drug antibodies against therapeutic peptides

The emergence of anti-drug antibodies (ADAs) poses significant impacts on the bioactivity and toxicity of biotherapeutics including proteins and peptides. Developing reliable assays to monitor the magnitudes of ADAs in blood samples is therefore considered a crucial task in animal and human studies throughout the development of biotherapeutics. Peptides represent a significant and fast-growing category of biotherapeutics for the management of a variety of indications. While peptides generally exhibit lower immunogenicity risks compared to biologics of larger sizes, drug developers are still required to conduct the risk-based immunogenicity assessment as mandated by the regulatory authorities. To address the need for efficient detection of ADAs against therapeutic peptides, we established a straightforward electrochemiluminescence immunoassay (ECLIA) based on direct binding strategy. Our assay demonstrates its applicability across various peptide therapeutics including marketed drugs and internal investigational compounds. Through stepwise tuning of the assay procedure, we identified several key factors such as buffer, detection reagent, plate type, and conjugation strategy that collectively contribute to the assay performance. Depending on the drug molecule and positive control antibody, the assay can achieve low single-digit to two-digit ng/ml sensitivity and ideal drug tolerance. In conclusion, this ECLIA platform presents a valuable and generic tool to expedite the development and validation of ADA assays for peptide-based therapeutics. • Direct binding format is the optimal assay configuration to detect anti-drug antibodies against therapeutic peptides. • The choice of blocking buffer and sample diluent elicits fundamental impact to the assay output. • Anti-specie antibodies outperform protein A/G as the detection reagent to achieve adequate assay sensitivity. • The assay performance might be significantly improved by utilizing alternative chemical strategies for critical reagent conjugation.