CytomX Therapeutics announces first patient dosed with CX-801

CytomX Therapeutics announced that the first patient has been dosed with CX-801 monotherapy in a Phase 1 study in patients with solid tumors. CX-801 is a dually-masked interferon alpha-2b PROBODY cytokine with potential broad applicability in both traditionally immune-oncology sensitive as well as insensitive tumors. The CX-801 Phase 1 dose escalation study is designed to evaluate safety and signs of clinical activity for CX-801 as monotherapy and in combination with Merck’s anti-PD-1 therapy KEYTRUDA. In dose escalation, the Phase 1 study will enroll patients with select solid tumors including advanced melanoma, renal cell carcinoma, and head and neck squamous cell carcinoma to inform a potential decision to move into Phase 1b indication-specific dose expansion cohorts.