OncoMed Pharmaceuticals, Inc. announced that it has started a multi-center Phase 1b clinical trial of its first-in-class Wnt-pathway-targeting decoy receptor OMP-54F28 (Fzd8-Fc) with nab-paclitaxel (Abraxane(R)) and gemcitabine in pancreatic cancer. This trial is the first of three Phase 1b trials for OMP-54F28 expected to begin patient enrollment in the next few months as part of OncoMed's collaboration with Bayer Pharma AG. This study follows on the recent initiation of OncoMed's Phase 1b program for the Wnt-pathway-targeting antibody vantictumab (OMP-18R5, Anti-Fzd7).

The Phase 1b clinical trial is a dose escalation study of OMP-54F28 in combination with nab-paclitaxel and gemcitabine in patients with first-line Stage IV pancreatic cancer. Primary objectives of the trial are to evaluate safety of this combination regimen and determine a recommended Phase 2 dose for OMP-54F28 in combination with nab-paclitaxel and gemcitabine. Key secondary and exploratory objectives include evaluation of the pharmacokinetics (PK) and pharmacodynamics (PD) of OMP-54F28, as well as the efficacy of this combination.

Tumor tissue from patients will be used to explore predictive biomarker hypotheses related to the efficacy of OMP-54F28. This first Phase 1b study for OMP-54F28 will be followed shortly by two additional Phase 1b studies. Interim results for the single-agent, first-in-human Phase 1a trial for OMP-54F28 in solid tumor patients were recently presented at the 2013 AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics in Boston.

Results from the Phase 1a study showed that OMP-54F28 is well tolerated and modulates the Wnt pathway starting at low doses, as evidenced by PD biomarker analysis of hair follicles. OncoMed recently initiated Phase 1b studies for its other Wnt-pathway-targeting product candidate, vantictumab, in HER2-negative breast cancer, non-small cell lung cancer and pancreatic cancer.