SCR-A019

SCR-A019 is a first-in-class biparatopic antibody-drug conjugate (ADC) targeting mesothelin (MSLN), developed by Simcere Zaiming. It consists of a biparatopic antibody that recognizes two distinct epitopes on MSLN, conjugated to a novel topoisomerase I inhibitor payload (CPT116) via a hydrophilic cleavable linker with a drug-to-antibody ratio (DAR) of 6. The biparatopic design is specifically engineered to prefer binding to membrane-bound MSLN over soluble MSLN, addressing the challenge of MSLN shedding which often limits the efficacy of conventional MSLN-targeted therapies. In preclinical studies, SCR-A019 has demonstrated potent cytotoxicity and anti-tumor activity in MSLN-positive models of lung and ovarian cancer.