About Vantictumab (OMP-18R5)Vantictumab is a first-in-class antibody that has shown broad anti-CSC and anti-tumor activity in patient-derived xenograft tumor models. Vantictumab inhibits a key signaling pathway in cancer, the Wnt pathway. Specifically, vantictumab selectively targets Frizzled receptors, which are activators of Wnt signaling. Although vantictumab was originally identified by binding to Frizzled7, the antibody selectively targets five different Frizzled receptors. OncoMed is currently completing a Phase 1a study of vantictumab in patients with advanced solid tumors. Preliminary data from this clinical trial were presented at the European Cancer Conference (ECC 2013) in September 2013 in Amsterdam, NL. Biomarker data for this Phase 1a trial were presented at the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics in Boston, MA, in October 2013. 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. 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.