OncoMed Pharmaceuticals, a clinical-stage company developing novel therapeutics that target cancer stem cells (CSCs), or tumor-initiating cells, has earned a $15 million milestone payment from Bayer Pharma related to achieving a dose escalation milestone in the phase Ia clinical trial of OMP-54F28 (Fzd8-Fc). OMP-54F28 is an antagonist of the Wnt pathway, a key cancer stem cell pathway. 

The phase Ia clinical trial of OMP-54F28 is an open-label dose escalation study in patients with advanced solid tumors. It is designed to assess OMP-54F28 for safety, immunogenicity, pharmacokinetics, biomarkers and initial signals of efficacy. In the ongoing study, OMP-54F28 has been well-tolerated at doses up to 15mg/kg every three weeks, which is above the target efficacious dose based on OncoMed's preclinical studies in minimally passaged human tumor xenograft models. 

Jakob Dupont, M.D., OncoMed's chief medical officer, said, "OMP-54F28 demonstrates promising tolerability and early signs of potential anti-tumor activity, as well as Wnt pathway modulation in clinical samples. The early clinical data from the OMP-54F28 program indicate that this compound is a distinct and differentiated Wnt pathway antagonist that is ready for later-stage clinical development in combination with standard-of-care chemotherapy and targeted therapy."

"OncoMed has achieved a total of $33 million in milestone payments this year from our two corporate partners," said Paul J. Hastings, chairman and CEO of OncoMed Pharmaceuticals. "We look forward to initiating multiple phase Ib studies for OMP-54F28 in the coming months in parallel with the continued advancement of our four other ongoing anti-cancer stem cell clinical programs."

OMP-54F28 is one of five anti-CSC product candidates currently being advanced through clinical studies by OncoMed and the company's second distinct Wnt-pathway modulating therapeutic to enter the clinic as part of the collaboration between OncoMed and Bayer. OncoMed's first Wnt pathway anti-cancer stem cell compound, vantictumab (OMP-18R5, Anti-FZD7), is being advanced into three phase Ib combination clinical studies. The first of these trials was recently initiated in patients with advanced breast cancer to evaluate the combination of vantictumab with paclitaxel. Bayer retains an option to exclusively license OMP-54F28 and/or vantictumab at any point through completion of certain phase I trials.