SAN DIEGO, June 17, 2014 /PRNewswire/ -- Mirati Therapeutics, Inc. (NASDAQ: MRTX) announced that mocetinostat, the company's spectrum selective HDAC inhibitor, has been granted Orphan Drug Designation by the U.S. Food & Drug Administration as a treatment for myelodysplastic syndrome (MDS). Mocetinostat is being developed in Phase 2 clinical studies in combination with Vidaza as a treatment for intermediate and high-risk MDS, as well as a single agent treatment in patients with diffuse large B-cell lymphoma (DLBCL) and bladder cancer targeting specific genetic mutations in histone acetylation that increase the likelihood of response in tumor cells. "Orphan designation is an important piece of the development plan for mocetinostat as we evaluate combination and single agent clinical development opportunities for the program," said Dr. Charles Baum, president and CEO of Mirati. "We are excited about the opportunity to identify and select patients whose cancers may be especially sensitive to mocetinostat, and we expect to have initial data from Phase 2 studies by the end of the year which will allow us to move quickly into a registration path." The FDA's Office of Orphan Drug Products grants orphan status to support development of medicines for underserved patient populations or rare disorders that affect fewer than 200,000 people in the United States. Orphan drug designation provides certain benefits, including market exclusivity upon regulatory approval if received, exemption of FDA application fees and tax credits for qualified clinical trials. "HDAC inhibitors may significantly increase the efficacy of other epigenetic agents such as inhibitors of LSD1, EZH2 and DOT1L as well as hypomethylating agents such as Vidaza in the treatment of MDS and other malignancies," added Baum. "Epigenetic pathways can become dysregulated during cancer progression through a variety of mechanisms, including the genetic alteration of pathways that control DNA methylation and histone modification. These alterations often result in silencing of selected tumor suppressor genes and uncontrolled tumor growth in certain malignancies including MDS, lymphomas and solid tumors such as bladder cancer."