Strategies to develop highly drug-tolerant cell-based neutralizing antibody assay: neutralizing antidrug antibodies extraction and drug depletion.

Drug interference poses great analytical challenges for cell-based neutralizing antidrug antibodies (NAb) assay. The work aimed to improve assay drug tolerance through biotin-drug extraction with acid dissociation method optimization and developing new approach. The NAb extraction with biotin-drug extraction with acid dissociation approach has been optimized by reducing biotinylated drug leaching and improving NAb elution efficiency, resulting in drug tolerance of up to 160 μg/ml. To circumvent the low acid elution efficiency of NAb from drug, a novel drug depletion approach was developed, which combined acid dissociation and drug targeted crosslinked capture, achieved drug tolerance up to 400 μg/ml. At last, a strategy workflow for sample pretreatment approach selection and optimization was established for improving drug tolerance of NAb assay. We demonstrated that reduced biotinylated drug leaching and the high NAb elution efficiency was critical for improving assay drug tolerance. Drug depletion offers an alternative approach to overcome low NAb elution efficiency.