YL222

YL222 is a PD-L1-targeting antibody-drug conjugate (ADC) developed by MediLink Therapeutics in collaboration with Henlius. It is constructed using MediLink's proprietary TMALIN (Tumor Microenvironment Activable LINker) platform, which is designed to improve the therapeutic index by enabling dual cleavage of the linker in both the extracellular tumor microenvironment and intracellular lysosomes. This mechanism facilitates a potent bystander effect while maintaining systemic stability. The ADC comprises a humanized anti-PD-L1 monoclonal antibody conjugated to a novel DNA topoisomerase I inhibitor payload. By targeting PD-L1, YL222 aims to deliver cytotoxic therapy directly to tumor cells and potentially overcome immune evasion by blocking the PD-1/PD-L1 pathway. It is currently in Phase 1 clinical development for patients with advanced solid tumors.