OncoMed Presents Vantictumab Biomarker Data at the San Antonio Breast Cancer Symposium (SABCS)

Six-Gene Predictive Biomarker Identified for Use in Breast Cancer

Redwood City, California, UNITED STATES

REDWOOD CITY, Calif., Dec. 11, 2015 (GLOBE NEWSWIRE) -- OncoMed Pharmaceuticals Inc. (NASDAQ:OMED) presented new data related to the development of a novel predictive biomarker for vantictumab (anti-Fzd7, OMP-18R5) at the San Antonio Breast Cancer Symposium (SABCS).  The presentation at SABCS detailed the identification and validation of a novel six-gene signature assay being evaluated as a predictive biomarker of response to vantictumab plus paclitaxel in the treatment of breast cancer.  Vantictumab is being studied in three Phase 1b combination clinical trials, including one with paclitaxel in patients with Her2-negative breast cancer. 

“The research presented today is one example of OncoMed’s efforts to identify biomarkers early and aggressively that can be evaluated alongside our therapeutic candidates in order to optimize treatment regimens and patient outcomes,” said John Lewicki, Ph.D. Executive Vice President and Chief Scientific Officer of OncoMed.  “In preclinical testing, the six-gene biomarker assay has been strongly predictive of anti-tumor responses to treatment with vantictumab in Her2-negative breast cancers.  If these results are corroborated in our ongoing clinical study of vantictumab in breast cancer, it will provide an excellent opportunity to develop a companion diagnostic and tailor vantictumab use to patients with the highest likelihood of benefit.”

The six-gene Wnt pathway-related biomarker was identified by using gene expression data from breast cancer xenografts in OncoMed’s patient-derived tumor bank with established in vivo response to vantictumab plus standard-of-care.  The six-gene signature was tested in 18 xenograft models and effectively predicted anti-tumor responses to treatment.  The biomarker was developed as a robust qPCR assay and validated with repeatability studies conducted across different days and in different labs.  Prevalence of the six-gene signature is estimated to be approximately 43 percent in Her2-negative patients.  In collaboration with Almac Diagnostics, the assay has been successfully developed and is being deployed in OncoMed’s ongoing Phase 1b study of vantictumab in Her2-negative breast cancer.

These data were presented today in a poster titled Development of a 6-gene qPCR RUO-validated assay as a predictive biomarker for response of vantictumab (OMP-18R5; anti-frizzled) in HER2- breast cancer patients (# P3-07-57) during the “Prognostic and Predictive Factors: Response Predictions – Biomarkers and Other Factors” poster session.

About Vantictumab (anti-Fzd7, OMP-18R5)
Vantictumab is a first-in-class antibody that inhibits a key signaling pathway in cancer, the Wnt pathway by selectively targeting Frizzled receptors 1, 2, 5, 7 and 8.  In patient-derived xenograft models, vantictumab has shown broad anti-cancer stem cell and anti-tumor activity.  Vantictumab is now being tested in combination with standard-of-care chemotherapy in three Phase 1b clinical trials in: 1) advanced NSCLC (vantictumab + docetaxel); 2) advanced HER2-negative breast cancer (vantictumab + paclitaxel); and 3) advanced pancreatic cancer (vantictumab + gemcitabine + Abraxane®).  Vantictumab is part of OncoMed's collaboration with Bayer Pharma AG.

Vantictumab is a novel investigational therapeutics currently being evaluated in ongoing clinical trials.  Patients interested in participating in one of OncoMed's many clinical trials may learn more by calling 1-866-914-7347 or emailing oncomed@emergingmed.com.

About OncoMed Pharmaceuticals
OncoMed Pharmaceuticals is a clinical-stage company focused on discovering and developing novel anti-cancer stem cell and immuno-oncology therapeutics.  OncoMed has seven anti-cancer product candidates in clinical development, including demcizumab (anti-DLL4, OMP-21M18), tarextumab (anti-Notch2/3, OMP-59R5), brontictuzumab (anti-Notch1, OMP-52M51), anti-DLL4/VEGF bispecific antibody (OMP-305B83), vantictumab (anti-FZD7, OMP-18R5), ipafricept (FZD8-Fc, OMP-54F28), and anti-RSPO3 (OMP-131R10), which each target key cancer stem cell signaling pathways including Notch, Wnt and R-spondin-LGR.  OncoMed has formed strategic alliances with Celgene Corporation, Bayer Pharma AG and GlaxoSmithKline (GSK).  A wholly owned immuno-oncology candidate, GITRL-Fc, and an undisclosed immuno-oncology target that is part of OncoMed’s collaboration with Celgene are being advanced toward clinical trials in the 2016-2017 timeframe. 

Please see the company's website at www.oncomed.com for additional information.

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 potential utility of the six-gene signature as a predictive biomarker for the response of breast cancer to treatment with vantictumab plus paclitaxel; and OncoMed’s opportunity to develop a companion diagnostic for vantictumab that allows identification of patients with the highest likelihood of benefit. Such risks and uncertainties include, among others, the uncertainties inherent in the preclinical and clinical development 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 additional capital to support the development of its unpartnered programs; OncoMed's reliance on third parties to conduct certain preclinical studies and all of its clinical trials; and OncoMed's reliance on single source third-party contract manufacturing organizations to manufacture and supply its 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 Annual Report on Form 10-K for the fiscal year ended December 31, 2014, filed with the Securities and Exchange Commission (SEC) on March 12, 2015, OncoMed's Quarterly Report on Form 10-Q for the fiscal quarter ended March 31, 2015, filed with the SEC on May 7, 2015, OncoMed's Quarterly Report on Form 10-Q for the fiscal quarter ended September 30, 2015, filed with the SEC on November 5, 2015, and OncoMed's other periodic reports filed with the SEC.

OncoMed Pharmaceuticals
Michelle Corral
Senior Director, Investor Relations and Corporate Communications
(650) 995-8373

Shari Annes
Annes Associates
(650) 888-0902