A competitive ligand-binding assay to detect neutralizing antibodies to a bispecific drug using a multiplex Meso Scale Discovery platform

Monitoring appearance of neutralizing antibodies (NAbs) to multidomain large molecule drugs is a challenging task. Here, we report development of a competitive ligand-binding assay for detection of NAbs to a bispecific candidate drug using a multiplex Meso Scale Discovery platform, which allows for detection of NAbs to both drug arms in the same sample. The assay has sensitivity better than 250 ng/ml and is tolerant to the presence of drug at concentration >600 μg/ml and to the level of soluble target(s) >400 ng/ml. Our data suggest that multiplex approach can be successfully used for development of NAb assays in competitive ligand-binding assay format.