Oncomed Pharmaceuticals Inc.'s shares dipped as much as 24 percent briefly after the company halted six phase Ib trials testing two Bayer AG-partnered monoclonal antibodies targeting the Wnt pathway in cancer. Trial sites reported "on-target mild-to-moderate" bone-related adverse events, moving the company to stop the trials to amend study protocols for all eight ongoing trials of vantictumab and Fzd8-Fc.