CytomX updated clinical data for its conditionally activated (masked) EpCAM-targeting ADC, Varsetatug masetecan (Varseta‑M), reporting objective response rates of about 32% at a 10 mg/kg dose in an expanded colorectal cancer cohort and progression‑free survival of roughly seven months in responders. The company said safety remained manageable with diarrhea as the principal adverse event. The expanded Phase I readout underlines progress for masked ADCs that aim to widen therapeutic windows for tumor antigens traditionally considered undruggable. CytomX said it will discuss next steps with regulators and present additional data at upcoming medical meetings. Investors reacted positively, sending shares higher and prompting renewed interest in masked and conditionally activated drug modalities that could reduce off‑tumor toxicity while delivering payload potency.