The FDA granted fast track designation to CytomX’s varsetatug masetecan (Varseta-M; CX-2051), an EpCAM-directed masked, conditionally activated antibody-drug conjugate, for relapsed or refractory metastatic colorectal cancer. The designation is based on Phase 1 dose-expansion results from the CTMX-2051-101 trial. Across expansion doses, confirmed objective response rates ranged from 6% to 32%, with a disease control rate of 88% overall. Diarrhea was the most common treatment-related adverse event, including grade 3 events in a subset receiving an updated prophylactic regimen.