OncoMed Pharmaceuticals, Inc. announced initial results from the Phase 1a dose escalation portion of a Phase 1a/b trial of etigilimab, the company's anti-TIGIT antibody. TIGIT (T-cell immunoreceptor with Ig and ITIM domains) is a next generation checkpoint receptor shown to block T-cell activation and the body's natural anti-cancer immune response. OncoMed's anti-TIGIT checkpoint inhibitor candidate is an IgG1 monoclonal antibody which binds to the human TIGIT receptor on T-cells with a goal of improving the activation and effectiveness of T-cell and NK cell tumor-killing activity. The data were presented today at the Society for Immunotherapy of Cancer meeting taking place in Washington, D.C. The initial results from the Phase 1a dose escalation portion of the Phase 1a/b trial included data from 18 patients with a variety of late stage metastatic cancers including colorectal, endometrial, pancreatic, among others, who were treated with etigilimab at doses ranging from 0.3 to 20 mg/kg every other week. There were no dose-limiting toxicities through the 20 mg/kg every other week dose. In this all comers difficult-to-treat patient population, stable disease was observed in 7 (38.9%) patients with prolonged disease control seen in some patients with the longest durations of stable disease being 205 and 225 days. Of the remaining 11 patients in the study, ten patients had progressive disease, and one patient did not meet criteria to be evaluated for efficacy. The most frequent treatment-related adverse events were rash (27.8%), fatigue (16.7%), nausea (16.7%), pruritus (16.7%), and cough (11.1%). Immune-related adverse events, signaling immune activation included rash (27.8%), pruritus (16.7%), autoimmune hepatitis (5.6%) and stomatitis (5.6%). Grade 3 or higher treatment-related AEs included rash (16.7%), and abdominal pain, embolism, hypertension, and pulmonary embolism (11.1% each).