REDWOOD CITY, Calif., June 13, 2014 (GLOBE NEWSWIRE) -- OncoMed Pharmaceuticals Inc. (Nasdaq:OMED), today announced that the company has voluntarily halted patient enrollment and dosing in its ongoing Phase 1 clinical trials of its two Wnt pathway inhibitor programs, vantictumab (anti-Fzd7, OMP-18R5) and Fzd8-Fc (OMP-54F28). OncoMed has been informed by the participating clinical sites of recent on-target mild-to-moderate bone-related adverse events for the two programs. To date, bone-related adverse events have been observed in 8 of 63 (13%) patients treated with vantictumab and 2 of 41 (5%) patients treated with Fzd8-Fc. After careful analysis of the recent mild-to-moderate adverse event incidents, OncoMed has halted enrollment and dosing in the Phase 1 studies for both programs as a precautionary measure. OncoMed, in conjunction with its academic bone expert advisors and study investigators, continues to analyze the clinical data in order to submit amended protocols to the U.S. Food and Drug Administration (FDA) and subsequently to the clinical study sites. The amendments for the Phase 1b combination trials will include 1) modified dosing regimens, such as lower and less frequent dosing, 2) updated risk mitigation measures, such as increased monitoring and bone protection strategies, and 3) modified enrollment criteria. Enrollment and dosing of new patients is expected to resume once amendments go through the process of review by the FDA and approval by the study sites' institutional review boards (IRBs). In parallel, the company intends to continue existing or modified dosing of those patients in the completed single-agent Phase 1a clinical trials for both vantictumab and Fzd8-Fc who have remained on treatment with the investigational agent for extended periods of time without disease progression and without significant drug-related adverse events. OncoMed has notified the FDA of these actions. "With patient safety as our first priority, we aim to fully understand these events, continue to conduct a thorough analysis of data in hand, and work closely with the investigators and the FDA to determine the best path forward," stated Paul J. Hastings, Chairman and Chief Executive Officer of OncoMed.