HPPA as assay substrate for improved capturing of sample variability during cut point analyses in immunogenicity testing

Aims Immunogenicity testing is a key component of protein drug development, with ADA bridging assays recognized as the gold standard method. These assays employ labeled therapeutic drugs for capture and detection, with the substrate playing a critical role in generating a detectable signal to differentiate the presence of anti-drug antibodies (ADAs) from nonspecific binding. This study investigates the impact of substrate choice on the assay's ability to capture individual sample variability, focusing on screening and confirmatory cut points (SCP and CCP).