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OncoMed Publishes Data on Tarextumab's Anti-Cancer Stem Cell Activity in Clinical Cancer Research

REDWOOD CITY, Calif., May 1, 2015 (GLOBE NEWSWIRE) -- OncoMed Pharmaceuticals, Inc. (Nasdaq:OMED), today announced that data summarizing preclinical study results for its anti-Notch2/3 antibody, tarextumab (OMP-59R5) were published in the May 1, 2015 edition of Clinical Cancer Research. The article details tarextumab's anti-tumor effects alone and in combination with chemotherapy and elucidates the drug candidate's mechanisms of activity. Additionally, data is presented describing the basis for biomarker identification of tumors with increased sensitivity to treatment with tarextumab.

"The early evidence of activity that we are seeing for tarextumab in our clinical trials is consistent with results of our preclinical studies. For instance, the Phase 1b biomarker-delineated response rates and survival data for tarextumab in pancreatic cancer is similar to the preclinical evidence that tumors with high Notch3 gene expression are more likely to respond to treatment," said Paul J. Hastings, OncoMed's Chairman and Chief Executive Officer. "Tarextumab is currently being studied in two randomized Phase 2 clinical trials for pancreatic cancer and small cell lung cancer. We look forward to reporting additional clinical and biomarker data from our tarextumab program in the months to come."

Key findings from the paper, titled "Targeting Notch signaling with a Notch2/Notch3 antagonist (tarextumab) inhibits tumor growth and decreases tumor initiating cell frequency", include:

  • Tarextumab was efficacious in inhibiting the growth of preclinical patient-derived xenografts from various solid tumor types, including lung, ovarian, breast and pancreatic cancers, indicating the potential for broad utility of tarextumab.
  • Tarextumab demonstrated a dual mechanism of action: inhibiting signaling of Notch2 and Notch3 in tumor cells and modulating the function of tumor vasculature through its action on pericytes.
  • Inhibition of Notch signaling in tumor cells was associated with a reduction in cancer stem cell frequency, promotion of tumor cell differentiation and a delay in tumor recurrence following chemotherapy treatment.
  • Tumor sensitivity to treatment with tarextumab in combination with chemotherapy was significantly higher in pancreatic tumors that had a higher level of Notch3 gene expression. Based on these data, Notch3 gene expression is being evaluated as a potential predictive biomarker for tarextumab in ongoing clinical trials.

"In this paper, we show that the blockade of Notch signaling with tarextumab sensitizes tumors to chemotherapy and reduces cancer stem frequency, delaying cancer recurrence as compared to chemotherapy alone," said Tim Hoey, Ph.D., Senior Vice President, Cancer Biology and a co-author of the paper. "Preclinical data for tarextumab, particularly as part of a combination regimen, provide a strong rationale for the utility of targeting Notch2 and Notch3 for cancer treatment, and suggest that this therapeutic approach may improve clinical outcomes. We are currently exploring the impact of this targeted anti-cancer stem cell agent in our Phase 2 clinical trials."

About Tarextumab (anti-Notch2/3, OMP-59R5)

Tarextumab (anti-Notch2/3, OMP-59R5) is a fully human monoclonal antibody that targets the Notch2 and Notch3 receptors. Preclinical studies have suggested that tarextumab exhibits two mechanisms of action: (1) by downregulating Notch pathway signaling, tarextumab appears to have anti-cancer stem cell effects, and (2) tarextumab affects pericytes, impacting stromal and tumor microenvironment. Tarextumab is currently being studied in two randomized Phase 2 clinical trials. The "ALPINE" study is assessing tarextumab with Abraxane® (paclitaxel protein-bound particles for injectable suspension) (albumin bound) plus gemcitabine in first-line advanced pancreatic cancer patients. The "PINNACLE" study is testing tarextumab in combination with etoposide and cisplatin and etoposide and carboplatin in first-line extensive stage small cell lung cancer patients. Data from OncoMed's Phase 1a and Phase 1b clinical trials of tarextumab indicate that the antibody is well tolerated, with on-target modulation of the Notch signaling pathway and signs of anti-tumor activity. Tarextumab is part of OncoMed's collaboration with GlaxoSmithKline (GSK). GSK has an option to obtain an exclusive license to tarextumab during certain time periods through completion of the proof-of-concept Phase 2 trials.

About OncoMed Pharmaceuticals

OncoMed Pharmaceuticals is a clinical-stage company focused on discovering and developing novel therapeutics targeting cancer stem cells (CSCs). OncoMed has six anti-cancer product candidates in clinical development, the most advanced of which are in randomized Phase 2 clinical trials. 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), and ipafricept (FZD8-Fc, OMP-54F28) each target key cancer stem cell signaling pathways including Notch and Wnt. OncoMed recently filed an Investigational New Drug application for anti-RSPO3 (OMP-131R10), an antibody targeting a third key cancer stem cell signaling pathway called R-spondin-LGR. OncoMed is also pursuing discovery of additional novel anti-CSC and cancer immuno-oncology 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: www.oncomed.com.

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 of the biomarker program in OncoMed's ongoing tarextumab clinical studies; the potential for the therapeutic approach of targeting Notch2 and Notch3, including tarextumab, to improve clinical outcomes; and the timing of the reporting of additional clinical and biomarker data from the tarextumab program. 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 additional 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 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.

CONTACT: Media & Investors OncoMed Pharmaceuticals Michelle Corral Investor Relations and Corporate Communications michelle.corral@oncomed.com (650) 995-8373 Investors Shari Annes Annes Associates shari.annes@oncomed.com (650) 888-0902

Source:OncoMed Pharmaceuticals, Inc.