SOUTH SAN FRANCISCO, Calif., May 19, 2025 (GLOBE NEWSWIRE) -- CytomX Therapeutics, Inc. (Nasdaq: CTMX), a leader in the field of masked, conditionally activated biologics, today announced that the first patient has been dosed with CX-801 in combination with KEYTRUDA® (pembrolizumab), Merck's anti- PD-1 therapy, in the ongoing Phase 1 dose escalation study (NCT06462794) evaluating safety and initial clinical activity in patients with metastatic melanoma. CX-801 is a dually masked interferon (IFN) alpha-2b PR ...