REDWOOD CITY, Calif., Feb. 3, 2014 (GLOBE NEWSWIRE) -- OncoMed Pharmaceuticals, Inc. (Nasdaq:OMED), a clinical-stage company developing novel therapeutics that target cancer stem cells (CSCs), or tumor-initiating cells, today announced the issuance of its fourth broad U.S. patent relating to antibodies that target the RSPO-LGR cancer stem cell pathway. The new patent, U.S. Patent No. 8,628,774, covers certain methods of treating cancer with antibodies that bind human leucine-rich repeat-containing G protein-coupled receptor (LGR) proteins and either disrupt the binding of such proteins to their ligands, the R-spondin (RSPO) proteins, or disrupt RSPO activation of LGR signaling. RSPO-LGR pathway patents previously granted to OncoMed include U.S. Patent Nos. 8,158,757, 8,158,758 and 8,540,989. OncoMed's broad RSPO-LGR pathway patents stem from patent applications filed after OncoMed scientists made certain key discoveries about the RSPO-LGR pathway several years ago. Since then, OncoMed has identified multiple antibodies targeting the RSPO-LGR pathway and demonstrated the activity of these antibodies in preclinical studies. An Investigational New Drug (IND) filing for anti-RSPO3, OncoMed's first antibody targeting the RSPO-LGR pathway, is planned for late 2014 or early 2015. OncoMed's RSPO-LGR pathway programs are part of OncoMed's recent collaboration with Celgene Corporation. "OncoMed's latest broad RSPO-LGR pathway patent is a great addition to our extensive IP portfolio," said Paul J. Hastings, Chairman and Chief Executive Officer of OncoMed. "RSPO-LGR is a potentially important cancer stem cell pathway and our research programs have generated a number of antibodies, including anti-RSPO3, with encouraging anti-CSC preclinical data." 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.