The FDA granted fast track designation to CytomX Therapeutics’ varsetatug masetecan (Varseta-M; CX-2051), an EpCAM-directed masked antibody-drug conjugate for relapsed/refractory metastatic colorectal cancer. The designation follows phase 1 dose-expansion data from the CTMX-2051-101 trial. CytomX reported confirmed objective response rates ranging from 6% to 32% across prioritized expansion doses and a disease control rate of 88% overall across the efficacy-evaluable population. Median progression-free survival was reported in the 5–7 month range, depending on dose cohort. Diarrhea was the most common treatment-related adverse event, with grade 3 events occurring in 10% at one regimen. The fast track path supports a planned first registrational study in the first half of 2027. If realized, Varseta-M could join the growing ADC pipeline targeting epithelial solid tumors through localized activation in the tumor microenvironment.