REDWOOD CITY, Calif., Feb. 18, 2014 (GLOBE NEWSWIRE) -- OncoMed Pharmaceuticals, Inc. (Nasdaq:OMED), a clinical-stage company developing novel therapeutics that target cancer stem cells (CSCs), or tumor-initiating cells, today announced that it has started a multi-center Phase 1b clinical trial of OMP-54F28 (Fzd8-Fc) with sorafenib (Nexavar®) in hepatocellular cancer (HCC). OMP-54F28 is a first-in-class Wnt-pathway-targeting decoy receptor and is part of OncoMed's collaboration with Bayer Pharma AG (Bayer). This is the second of three Phase 1b trials for OMP-54F28 to begin patient enrollment; earlier this year OncoMed initiated a Phase 1b of OMP-54F28 with nab-paclitaxel (Abraxane®) and gemcitabine in pancreatic cancer.

The Phase 1b clinical trial is a dose-escalation study of OMP-54F28 in combination with sorafenib in patients with first-line locally advanced or metastatic HCC. 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 sorafenib. 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.

Safi Shahda, M.D., Assistant Professor of Clinical Medicine at Indiana University in Indianapolis, IN, is the principal investigator who treated the first patient enrolled in this study. Dr. Shahda commented, "Hepatocellular cancer is a devastating form of liver cancer that is a significant cause of cancer-related death worldwide. Patients with more advanced disease have very few treatment options. OMP-54F28 holds the potential to make a real difference for these patients as it was designed to attack so-called cancer stem cells that can generate new cancer cells and are particularly resistant to currently available cancer drugs."

Five additional investigators and clinical sites are participating in this trial: Celina Ang, M.D., Mount Sinai Hospital, New York, NY; Crystal Denlinger, M.D., Fox Chase Cancer Center, Philadelphia, PA; Anthony El-Khoueiry, M.D., University of Southern California, Los Angeles, CA; Thomas Purcell, M.D., M.B.A., University of Colorado, Aurora, CO, and Andrew Zhu, M.D., Ph.D., Dana-Farber/Harvard Cancer Center, Boston, MA.

"Preclinical data suggest that OMP-54F28 adds significant anti-tumor activity to sorafenib by eradicating tumor-initiating cells in models for hepatocellular cancer. The safety profile for OMP-54F28 in the single-agent Phase 1 study is favorable, and we will now explore its ability to combine with sorafenib in preparation for future potential randomized studies," said Jakob Dupont, M.D., Chief Medical Officer of OncoMed.

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 pharmacodynamic biomarker analysis of hair follicles.

"One of our goals for 2014 is to have all six of the planned Phase 1b combination clinical studies up and running for our anti-cancer stem cell candidates targeting the Wnt pathway. With two of three Phase 1b combination clinical studies now underway for OMP-54F28, and the initiation of all three planned Phase 1b studies for vantictumab late last year, we are very close to achieving that objective," said Paul J. Hastings, OncoMed's Chairman and Chief Executive Officer. "Data generated from these studies will provide the basis for Bayer to exercise their option to license OMP-54F28 and vantictumab and the trials will also serve to inform future Phase 2 clinical studies of these novel drug candidates."

About OMP-54F28 (Fzd8-Fc)

OMP-54F28 is a first-in-class fusion protein that has shown broad anti-CSC and anti-tumor activity in patient-derived xenograft tumor models. OMP-54F28 inhibits a key signaling pathway in cancer, the Wnt pathway.  Specifically, OMP-54F28 consists of the extracellular ligand-binding domain of the Frizzled 8 receptor and the Fc domain of a human IgG1 antibody.  OMP-54F28 selectively binds Wnt ligands, which are activators of Wnt signaling.  OMP-54F28 is currently in Phase 1a in patients with refractory solid tumors.  Data from the OMP-54F28 solid tumor trial were presented at the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics in Boston, MA, in October 2013.  Two Phase 1b clinical trials of OMP-54F28 are ongoing: one in pancreatic cancer (gemcitabine/Abraxane + OMP-54F28) and one in hepatocellular carcinoma (sorafenib + OMP-54F28). A third Phase 1b trial is planned for initiation in early 2014. OMP-54F28 is part of OncoMed's collaboration with Bayer.

About Cancer Stem Cells

Cancer stem cells, or CSCs, are the subpopulation of cells in a tumor responsible for driving growth and metastasis of the tumor. CSCs, also known as tumor-initiating cells, exhibit certain properties which include the capacity to divide and give rise to new CSCs via a process called self-renewal and the capacity to differentiate or change into the other cells that form the bulk of the tumor.  Common cancer drugs target bulk tumor cells but have limited impact on CSCs, thereby providing a path for recurrence of the tumor.  OncoMed's product candidates target CSCs by blocking self-renewal and driving differentiation of CSCs toward a non-tumorigenic state, and also impact bulk tumor cells. OncoMed believes its product candidates are distinct from the current generations of chemotherapies and targeted therapies, and have the potential to significantly impact cancer treatment and the clinical outcome of patients with cancer.

About OncoMed Pharmaceuticals

OncoMed Pharmaceuticals is a clinical-stage company focused on discovering and developing novel therapeutics targeting cancer stem cells.  OncoMed has five anti-cancer product candidates in clinical development, including demcizumab (Anti-DLL4, OMP-21M18), OMP-59R5 (Anti-Notch2/3), OMP-52M51 (Anti-Notch1), vantictumab (Anti-Fzd7, OMP-18R5), and OMP-54F28 (Fzd8-Fc), which target key cancer stem cell signaling pathways including Notch and Wnt.  OncoMed has two other antibodies in preclinical development, Anti-DLL4/Anti-VEGF bispecific and Anti-RSPO3, with Investigational New Drug filings planned for late 2014 or early 2015.  OncoMed is also pursuing discovery of additional novel anti-CSC product candidates.  OncoMed has formed strategic alliances with Celgene Corporation, Bayer Pharma AG and GlaxoSmithKline (GSK). Additional information can be found at the company's website:

Forward-Looking Statements

To the extent that statements contained in this press release are not descriptions of historical facts regarding OncoMed Pharmaceuticals, they are forward-looking statements reflecting the current beliefs and expectations of management made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995, including OncoMed's expectations regarding the success of Phase 1b trials and a favorable safety profile for OMP-54F28 and vantictumab; the potential for opt-in decisions by Bayer regarding OMP-54F28 and vantictumab; the potential of OncoMed's product candidates such as OMP-54F28 to significantly impact cancer treatment and the clinical outcome of patients with cancer, and patients with hepatocellular cancer in particular; the potential for development of predictive biomarkers for OMP-54F28, particularly in hepatocellular cancer; the timing of clinical trials for OncoMed's product candidates, including the timing of an additional Phase 1b trial for OMP-54F28; and the timing of Investigational New Drug filings for OncoMed's product candidates, including Anti-DLL4/Anti-VEGF bispecific and Anti-RSPO3. Such forward-looking statements involve substantial risks and uncertainties that could cause OncoMed's clinical development programs, future results, performance or achievements to differ significantly from those expressed or implied by the forward-looking statements. Such risks and uncertainties include, among others, the uncertainties inherent in the preclinical and clinical development process; the risks and uncertainties of the regulatory approval process; OncoMed's dependence on its collaboration partners, including Celgene, GSK and Bayer, for the funding of its partnered programs; OncoMed's ability to raise capital to support the development of its unpartnered programs; OncoMed's dependence on the development and marketing efforts of its partners for the commercial success of its partnered product candidates; OncoMed's reliance on third parties to conduct certain preclinical studies and all of its clinical trials; OncoMed's reliance on single source third-party contract manufacturing organizations to manufacture and supply its product candidates; OncoMed's ability to validate, develop and obtain regulatory approval for companion diagnostics; OncoMed's ability to achieve market acceptance and commercial success of its product candidates once regulatory approval is achieved; OncoMed's ability to discover, develop and commercialize additional product candidates; the ability of competitors to discover, develop or commercialize competing products more quickly or more successfully; OncoMed's dependence on its Chairman and Chief Executive Officer, its Chief Scientific Officer, its Chief Medical Officer and other key executives; risk of third party claims alleging infringement of patents and proprietary rights or seeking to invalidate OncoMed's patents or proprietary rights; and the ability of OncoMed's proprietary rights to protect its technologies and product candidates. OncoMed undertakes no obligation to update or revise any forward-looking statements. For a further description of the risks and uncertainties that could cause actual results to differ from those expressed in these forward-looking statements, as well as risks relating to OncoMed's business in general, see OncoMed's Prospectus filed with the Securities and Exchange Commission on July 18, 2013 and OncoMed's Quarterly Report on Form 10-Q for the fiscal quarter ended September 30,2013, filed with the Securities and Exchange Commission on November 13, 2013.

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