anti-HER3 antibody-drug conjugate YL202

An antibody-drug conjugate (ADC) composed of a monoclonal antibody directed against human epidermal growth factor receptor 3 (HER3; ErbB3) conjugated via a tumor microenvironment (TME) activable protease-cleavable linker to a cytotoxic DNA topoisomerase I inhibitor, with potential antineoplastic activity. Upon administration of anti-HER3 ADC YL202, the anti-HER3 antibody moiety targets and binds to HER3 expressed on tumor cells. Upon proteolytic cleavage in the TME and the release of the topoisomerase I inhibitor, the topoisomerase I inhibitor targets and binds to DNA topoisomerase I, thereby stabilizing the cleavable complex between topoisomerase I and DNA and resulting in DNA breaks, inhibition of DNA replication and apoptosis in HER3-expressing tumor cells. HER3, a member of the epidermal growth factor receptor (EGFR) family of receptor tyrosine kinases, is frequently overexpressed in tumors.