Overcoming target interference in bridging anti-drug antibody (ADA) assay by optimizing sample treatment

Drug bridging immunoassays are widely employed as the standard approach for detecting anti-drug antibodies (ADAs) in the development of new biological entities. A major challenge in these assays is mitigating target interference, particularly when the soluble target exists in dimeric forms, which can result in false positive signals and compromise assay specificity. We developed sensitive and robust ADA assays capable of overcoming target interference to detect antibodies against BI X in both cynomolgus monkey (cyno) plasma and human serum matrices. This was achieved through the implementation of simple sample treatment techniques, specifically, acidification using a panel of different acids, to disrupt dimeric target interactions and minimize the interference. Optimization of the acid dissociation and subsequent neutralization steps significantly reduced target interference in both cyno and human matrices. These improvements were achieved without the need for additional assay development or complex depletion strategies. Compared to previously reported methods for mitigating target interference, the acid panel treatment approach is simpler, more time-efficient, and cost-effective. This user-friendly strategy can be readily applied to eliminate soluble dimeric targets during ADA method development, particularly in cases where alternative methodologies are not feasible or applicable.