OncoMed Pharmaceuticals, Inc. announced dosing of the first patient in a Phase 1b clinical trial of anti-DLL4/VEGF bispecific antibody (OMP-305B83) plus chemotherapy in patients with second-line metastatic colorectal cancer. The anti-DLL4/VEGF is the first antibody developed utilizing OncoMed’s BiMAb™ bispecific platform technology and is designed to have anti-cancer stem cell, immunomodulatory and anti-angiogenic activity. Thirty patients with metastatic colorectal cancer who have failed first-line treatment, typically bevicizumab plus FOLFOX (folinic acid, fluorouracil, oxaliplatin) chemotherapy, will receive second-line treatment in the Phase 1b multicenter, open-label dose escalation and expansion study of the anti-DLL4/VEGF bispecific antibody in combination with FOLFIRI (folinic acid, fluorouracil and irinotecan) chemotherapy. This trial is designed to determine the safety, preliminary efficacy, immunogenicity, pharmacokinetics and biomarker effects of the anti-DLL4/VEGF bispecific antibody plus FOLFIRI. A second Phase 1b study in patients with platinum resistant ovarian cancer is expected to begin enrolling patients soon. In an ongoing Phase 1a dose escalation and expansion study of OncoMed’s anti-DLL4/VEGF bispecific antibody as a single agent, interim data was presented on 51 patients with previously treated advanced solid tumors who were treated in the dose escalation portion of the trial. Additional patients are currently being enrolled in the expansion phase of the study. Anti-DLL4/VEGF bispecific antibody was generally well tolerated with hypertension, headache and pulmonary hypertension being the most common drug related toxicities. Single-agent anti-tumor activity was observed: two of 46 evaluable patients had a partial response and 12 other patients had a reduction in their tumor volume. One of the two colorectal patients on study had a reduction in tumor volume.