OncoMed Pharmaceuticals, a clinical-stage biopharmaceutical company focused on discovering and developing novel anti-cancer stem cell and immuno-oncology therapeutics, announced that Bayer Pharma has notified OncoMed of its decision not to exercise its option to license the first-in-class Wnt pathway inhibitors vantictumab (anti-Fzd, OMP-18R5) and ipafricept (Fzd8-Fc, OMP-54F28) for strategic reasons.

Effective June 2017, OncoMed will retain worldwide development and commercialization rights to vantictumab, ipafricept and all other Wnt pathway biologics under the collaboration.  The small molecule programme under the companies' collaboration continues without change.

"Under our collaboration with Bayer, we have received over $90 million in upfront and milestone payments that have fully funded the development of vantictumab and ipafricept. While we had looked forward to collaborating with the Bayer team on the late-stage development of these biotherapeutics, we are very pleased to have worldwide rights to two promising phase 2-ready assets," said Paul J. Hastings, chairman and chief executive officer of OncoMed. "We will be conducting an internal portfolio review and prioritization as we determine next steps for all our programs, including vantictumab and ipafricept.

Vantictumab and ipafricept are selective inhibitors of the Wnt pathway. In phase 1a and phase 1b clinical trials, vantictumab and ipafricept have each demonstrated safety and tolerability alone and in combination with standard-of-care chemotherapies in several solid tumors..  The company is completing two phase 1b combination clinical trials of vantictumab — one in HER2-negative breast cancer (vantictumab + paclitaxel) and one in advanced pancreatic cancer (vantictumab + gemcitabine + Abraxane) — and two phase 1b combination clinical trials of ipafricept — one in ovarian cancer (ipafricept + carboplatin + paclitaxel) and one in pancreatic cancer (ipafricept + gemcitabine + Abraxane).  Interim data presented from each of these trials during the 2016 ASCO Annual Meeting and the ESMO 2016 Congress showed early indications of anti-tumor activity. In preclinical studies, OncoMed researchers have observed evidence of synergies when these Wnt inhibitor compounds are administered sequentially following the use of taxane-based chemotherapies. Published preclinical studies also point to the Wnt pathway as being a possible potentiator of immune response in tumors.