Arno Therapeutics, Inc. (OTCBB: ARNI) announced today that its investigational compound, AR-42, has been granted orphan-drug designation by the U.S. Food and Drug Administration for the treatment of meningioma and schwannoma of the central nervous system. Meningioma and schwannoma are benign tumors that can present in different locations within the brain and the spinal cord and may cause substantial morbidity for those affected individuals. Glenn Mattes, President and Chief Executive Officer of Arno, stated: “We welcome these orphan-drug designations for AR-42 and look forward to advancing our clinical programs for this compound as soon as possible. AR-42 has shown promising activity in preclinical studies, which has encouraged us to pursue its clinical development in a variety of tumor types.” AR-42 is an orally available, broad-spectrum deacetylation inhibitor of both histone and non-histone proteins that play an important role in the regulation of gene expression, cell growth and survival. In preclinical studies, AR-42 has demonstrated anti-tumor activity in both meningioma and schwannoma. AR-42 has also shown greater potency and activity in solid tumors and hematological malignancies when compared to the approved HDAC inhibitor, vorinostat (also known as SAHA and marketed as Zolinza® by Merck). AR-42 is currently being studied in a Phase I/IIa clinical study in adult patients with relapsed or refractory hematologic malignancies and solid tumors. Orphan-drug designation is granted by the FDA Office of Orphan Products Development to promote the development of new therapies for rare diseases and disorders affecting fewer than 200,000 individuals in the United States. Among the benefits of orphan designation in the United States are seven years of market exclusivity following FDA approval, waiver or partial payment of application fees, and tax credits for clinical-testing expenses conducted after orphan designation is received. About Arno Therapeutics Arno Therapeutics is a clinical-stage biopharmaceutical company developing innovative products for the treatment of cancer. Arno has exclusive worldwide rights to develop and market three innovative clinical-stage anti-cancer product candidates with unique mechanisms of action. These compounds are in clinical testing as potential best- or first-in-class products to treat hematologic malignancies and solid tumors. For more information about the company, please visit www.arnothera.com. Forward-Looking Statements: This press release contains forward-looking statements that involve substantial risks and uncertainties. These statements are often, but not always, made through the use of words or phrases such as "anticipates," "expects," "plans," "believes," "intends," and similar words or phrases. These forward-looking statements include, without limitation, statements regarding the potential for onapristone to treat cancer and other diseases, the timing, progress and anticipated results of the clinical development of onapristone, Arno’s ability to fund the development of onapristone to completion, as well as Arno’s strategy, future operations, outlook, milestones, future financial position, future financial results, plans and objectives. We may not actually achieve these plans, intentions or expectations and Arno cautions investors not to place undue reliance on our forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements we make. Various important factors could cause actual results or events to differ materially from the forward-looking statements that we make. Such factors include, among others, risks that the results of clinical trials will not support our claims or beliefs concerning the effectiveness of onapristone or any of our other product candidates, our ability to finance the development of our product candidates, regulatory risks, and our reliance on third party researchers and other collaborators. Additional risks are described in the company's Annual Report on Form 10-K for the year ended December 31, 2010. Arno is providing this information as of the date of this press release and does not undertake any obligation to update any forward-looking statements as a result of new information, future events or otherwise.