In-depth characterization and semi-quantification of anti-drug antibodies in clinical samples using specific hybrid IC-LC-MS/MS methods

Anti-drug antibodies (ADAs) generated by biotherapeutics can impair the drug clearance, prevent the binding to its target or lead to hypersensitivity reactions, thereby affecting efficacy and safety. It is therefore essential to assess the immunogenicity of potential biotherapeutics, particularly in clinical development. Ligand binding assays (LBA) are the gold standard for ADA detection because of their high sensitivity and throughput. However, LBA assays don't provide details on the isotypes produced and their relative abundance. As certain isotypes are known to be associated with ADA mediated adverse events, this information could be helpful to anticipate or better characterize the immunogenicity risk of biotherapeutics. A hybrid IC-LC-MS/MS strategy was developed for the detection of specific isotypes/subclasses of ADAs in a phase I clinical study. A first approach using the biotinylated drug to capture ADAs in human serum allowed the simultaneous semi-quantification of all IgG subclasses and the detection of ADAs of the IgM isotype in clinical samples. These results enabled a detailed characterization of the immune response against the biotherapeutic. A second assay was developed using a sequential immunocapture to measure drug specific IgEs known to be potentially associated with hypersensitivity reactions. The overall results were consistent with the clinical adverse events observed in some healthy volunteers.