OncoMed Pharmaceuticals Receives First U.S. Patent on MAbTrap(TM) Antibody Display Technology

OncoMed Pharmaceuticals, Inc. (OMED), a clinical-stage company developing novel therapeutics that target cancer stem cells (CSCs), or tumor-initiating cells, today announced that the United States Patent and Trademark Office has granted OncoMed its first U.S. patent on its MAbTrap(TM) antibody display technology, one of the company's novel antibody platform technologies. OncoMed's MAbTrap(TM) technology enables the rapid identification of monoclonal antibodies that bind a particular target or set of targets, and bind such target or targets with high affinity and specificity. OncoMed has used the patented technology to identify and/or optimize novel antibodies, including proprietary bispecific antibodies, and demonstrated the activity of these antibodies in preclinical studies.

The new patent, U.S. Patent No. 8,551,715, relates to methods of producing libraries of cells that express membrane-bound antibodies or other specific binding agents on their surface, and methods of identifying the cells in such libraries that express an antibody or other agent having the desired binding characteristics. The patented methods include novel mammalian cell display methods. Related patent applications are currently pending in the U.S., Europe, Japan, China, and a number of other countries worldwide. The new patent and related applications are all solely owned by OncoMed.

"The MAbTrap(TM) technology was invented and developed at OncoMed and provides a versatile platform for creating next-generation antibodies with highly-tailored attributes," said Austin Gurney, Ph.D., OncoMed's Senior Vice President of Molecular and Cellular Biology. MAbTrap(TM) allows for the screening of large libraries of antibodies using mammalian or other cells for monoclonal antibody discovery and optimization. OncoMed's proprietary antibody platform technologies also include bispecific antibody technologies and hybridoma technologies.

"Our patented MAbTrap(TM) antibody display technology is an innovative and powerful tool for the discovery and optimization of antibodies," said Paul J. Hastings, Chairman and Chief Executive Officer of OncoMed. "We have already successfully used MAbTrap(TM) to identify promising new product candidates and expect this technology to continue to play an important role in our future efforts to identify and develop new generations of anti-cancer stem cell agents."

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 with Investigational New Drug filings planned for as early as 2014. OncoMed is also pursuing discovery of additional novel anti-CSC product candidates. OncoMed has formed strategic alliances with 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 scope, validity, enforceability, and duration of patent protection afforded by the referenced patents and OncoMed's other intellectual property; OncoMed's ability to successfully enforce its intellectual property and defend it against challenges by third parties; the capabilities and performance of the MAbTrap(TM) platform technology and the characteristics of antibodies that can be identified and/or optimized using the technology; OncoMed's ability to obtain additional patent protection for the MAbTrap(TM) platform technology in the U.S. and additional countries; OncoMed's ability to successfully use its platform technologies, and MAbTrap(TM) in particular, to identify and/or optimize new product candidates; the success of clinical trials for OncoMed's product candidates; the potential of OncoMed's product candidates to significantly impact CSCs, cancer treatment, and the clinical outcome of patients with cancer; and the timing of Investigational New Drug filings. 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 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 Prospectus filed with the Securities and Exchange Commission on July 18, 2013and OncoMed's Quarterly Report on Form 10-Q for the fiscal quarter ended June 30, 2013, filed with the Securities and Exchange Commission on September 3, 2013.

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