Development and validation of ELISA method for quantification of Q-1802 in serum and its application to pharmacokinetic study in ICR Mouse

Q-1802 is a humanized bispecific antibody targeting programmed death-ligand 1 (PD-L1) and Claudin 18.2 (CLDN18.2). It can bind to CLDN18.2 and mediate antibody-dependent cell-mediated cytotoxicity against tumor cells. The Fc segment of the antibody recognizing PD-L1 blocks PD-1 signaling and activates innate immunity and adaptive immunity. In this study, we report the development, validation, and application of sensitive and highthroughput enzyme-linked immunosorbent assays (ELISA) to measure the concentrations of Q-1802 in ICR mouse serum. The assay is sensitive, with a lower limit of quantification of 50 ng/mL, has a broad dynamic range of 50-3200 ng/mL, and exhibits excellent precision and accuracy. These assays were successfully applied to in vitro serum stability and pharmacokinetic (PK) studies. In conclusion, we have developed and validated a highly sensitive and selective method for measuring Q-1802 in ICR mouse serum. The development and validation steps of assays met the required criteria for validation, which suggested that these can be applied to quantify Q-1802, as well as in PK studies.