R800-MMAE

R800-MMAE is an antibody-drug conjugate (ADC) being developed by GO-therapeutics for the treatment of various solid tumors. It consists of R800, a humanized monoclonal antibody that specifically targets truncated O-glycans (cancer-specific glycopeptide epitopes), conjugated to the anti-mitotic payload monomethyl auristatin E (MMAE). The R800 antibody binds with low nanomolar affinity to these truncated glycans, which are expressed in 20-30% of triple-negative breast, lung, pancreatic, colorectal, and ovarian cancers, while remaining absent in healthy tissues. Upon internalization, the MMAE payload inhibits tubulin polymerization, leading to cell cycle arrest and apoptosis. Preclinical data presented at AACR 2025 demonstrated potent in vitro activity and significant tumor elimination in patient-derived xenograft (PDX) models with a minimum effective dose of 2 mg/kg.