CytomX’s Varsetatug Masetecan Shows Promising Late-Line CRC Data — CytomX Therapeutics, Inc.

Event summary

CytomX’s Varsetatug Masetecan (Varseta-M) demonstrated a 32% response rate at 10 mg/kg and 20% at 8.6 mg/kg in late-line colorectal cancer patients.
Median progression-free survival was 7.1 months at the higher dose and 6.8 months at the lower dose.
Grade 3 diarrhea rate improved to 10% with updated prophylactic strategies.
FDA interactions targeted for mid-2026 to align on potential registrational trial design.

The big picture

CytomX’s positive Phase 1 data for Varsetatug Masetecan positions it as a potential new treatment option in late-line colorectal cancer, an area with limited therapeutic options. The company is now targeting regulatory discussions to accelerate its path to market while exploring combination therapies and broader indications. Success here could solidify CytomX’s transition into a commercial-stage oncology player.

What we're watching

Regulatory Pathway: Whether the FDA will endorse a registrational trial design for Varseta-M in late-line CRC by mid-2026.
Combination Therapy: The pace at which CytomX advances combination studies with bevacizumab and chemotherapy, expected to start by year-end 2026.
Market Expansion: How CytomX plans to extend Varseta-M’s reach beyond CRC into other EpCAM-expressing cancers in the second half of 2026.