CytomX released expansion‑cohort results for its masked, conditionally activated antibody‑drug conjugate Varseta‑M in late‑line metastatic colorectal cancer, reporting response rates between 20% and 32% at the two higher doses and progression‑free survival improvements of roughly 6.8 to 7.1 months. The company said it will present more data at upcoming meetings and engage the FDA on monotherapy trial design. Investors rewarded the update: CytomX shares jumped to a 52‑week high as markets priced in commercial potential for an ADC that targets EpCAM via a tumor‑restricted activation mechanism. CytomX described diarrhea as the most common treatment‑related adverse event; the company noted improved prophylaxis but continued to monitor severe events in a minority of patients. Sources: CytomX press releases and Phase 1 expansion data disclosed to investors and medical meetings.