CytomX reported encouraging Phase 1 expansion data for its masked, conditionally activated antibody‑drug conjugate Varseta‑M in late‑line metastatic colorectal cancer, showing response rates up to ~32% at higher doses and improved progression‑free survival. The company said it will engage the FDA on monotherapy study design. Separately, Astellas terminated its multi‑year collaboration with CytomX that targeted T‑cell engaging bispecific formats, a move disclosed in CytomX’s Form 10‑K and press filings. Astellas had licensed Probody technology from CytomX; the split removes a strategic partner but leaves CytomX free to advance select targets independently. Varseta‑M’s conditional activation aims to widen the therapeutic window against EpCAM‑expressing tumors. CytomX CEO Sean McCarthy framed the new clinical data as validation of the platform while management reallocates internal priorities following the Astellas termination.