OncoMed Pharmaceuticals was founded in August 2004, by Drs. Michael F. Clarke and Max Wicha who led the discovery of cancer stem cells, in solid tumors. The cancer stem cell hypothesis suggests that tumors are composed of heterogeneous cell types and that cancer growth and metastasis are driven by a sub-population of cells within the tumor. The tumorigenic cells have been termed cancer stem cells because they exhibit certain properties similar to normal stem cells in adults that replenish tissues, such as the skin and the lining of the intestinal tract. These properties include: self-renewal, the capacity to differentiate into bulk tumor cells and the ability to proliferate extensively. Self-renewal is a unique property of stem cells and is defined as the ability to proliferate while maintaining an undifferentiated, multipotent state. Importantly, cancer stem cells differ from normal stem cells because they have accumulated oncogenic mutations that result in the loss of normal limitations on growth. These differences can be exploited to develop therapies that selectively target tumor initiating cells and not normal stem cells. Our founders invented techniques to identify the subset of cells within a tumor that have stem cell like properties. Injection of very small numbers of these cells into mice has led to the development of tumors that have the surface markers and microscopic appearance of the original human cancer. Subsequent experiments have shown that the tumor initiating cells are more resistant to standard chemotherapy agents and radiotherapy. This raises the possibility that some current treatments may succeed at initially decreasing the size of a cancer, but leave behind an increased proportion of the most malignant cells.

The ability to isolate and monitor tumor initiating cells using specific surface markers and flow cytometry has allowed OncoMed to carefully evaluate the importance of specific targets associated with key biologic pathways implicated in both stem cell biology and cancer. Antibodies against these targets have been developed and tested within xenograft models derived from freshly resected human cancers. We believe these models are more representative of the effects of these treatments in cancer patients than traditional models using cancer cell lines which may no longer accurately reflect the properties of the original tumor.

Using these approaches, OncoMed has a portfolio of active antibodies that target biologic pathways critical for survival of tumor initiating cells. The first of these antibodies should enter the clinic in 2008. Multiple additional promising therapeutic candidates that target other critical pathways are also being developed.

OncoMed Pharmaceuticals has attracted significant funding from a prominent group of investors, that include, US Venture Partners, Latterell Venture Partners, Morgenthaler Ventures,The Vertical Group, Adams Street Partners, De Novo Ventures and Bay Partners.