Rexahn Pharmaceuticals Announces Publication of Preclinical Data for Novel Anti-Cancer Compound RX-3117

Rexahn Pharmaceuticals

, a clinical stage biopharmaceutical company developing potential best-in-class oncology therapies, today announced the on-line publication of preclinical results for RX-3117 in a peer reviewed medical journal, Investigational New Drugs, in an article titled, “Metabolism, mechanism of action and sensitivity profile of fluorocyclopentenylcytosine (RX-3117; TV-1360)”. Investigational New Drugs is an interdisciplinary journal presenting the latest investigations and discussions of critical questions appropriate to the entire field of new anticancer drug development. Peter D. Suzdak, Ph.D., Rexahn's Chief Executive Officer, commented, “The broad spectrum of anti-tumor activity against human cancer cell lines, oral bioavailability in cancer patients, and improved preclinical and clinical safety profile suggest that RX-3117 may represent a major advance in the treatment of solid cancer tumors. Rexahn anticipates initiating a Phase I clinical study in cancer patients with solid tumors in the fourth quarter of 2013.” The published study characterized the broad spectrum of potent anti-tumor effects of RX-3117 against 50 different human cancer cell lines (including colon, lung, renal and pancreas) and its unique mechanism of activation in cancer cells. In addition, RX-3117 was shown to be effective in gemcitabine resistant human cancer cell lines. Although RX-3117 shares some properties with other nucleoside compounds such as gemcitabine, its cytotoxicity profile, metabolism and mechanism of action make it distinct and potentially clinically superior to existing nucleoside compounds. Prof. Dr. Godefridus J. (Frits) Peters, Head Laboratory Medical Oncology, VU University Medical Center, Amsterdam, The Netherlands, and lead author of the published results, commented, “RX-3117 is an exciting new nucleoside analog with unique properties both regarding its mechanism of action and its pharmacology. Its excellent oral bioavailability fits very well with the current tendency to give anticancer drugs orally. Its mechanism of action gives several leads for future combination therapies with different drugs.” About RX-3117 RX-3117 is a novel small molecule nucleoside compound that is incorporated into DNA or RNA of cancer cells and inhibits both DNA and RNA synthesis which induces apoptotic cell death of tumor cells. RX-3117 also mediates the down-regulation of DNA methyltransferase 1 (DNMT1), an enzyme responsible for the methylation of cytosine residues on newly synthesized DNA and also a target for anticancer therapies. Preclinical studies have shown RX-3117 to be effective in both inhibiting the growth of various human cancer xenograft models, including colon, lung, renal and pancreas, as well as overcoming chemotherapeutic drug resistance. RX-3117 has demonstrated a broad spectrum anti-tumor activity against 50 different human cancer cell lines and efficacy in 12 different mouse xenograft models. The efficacy in the mouse xenograft models was superior to that of gemcitabine. In addition, in human cancer cell lines made resistant to the anti-tumor effects of gemcitabine, RX-3117 still retains its full anti-tumor activity. In August 2012, Rexahn reported the completion of an exploratory Phase I clinical trial of RX-3117 in cancer patients conducted in Europe, to investigate the oral bioavailability, safety and tolerability of the compound. In this study, oral administration of RX-3117 demonstrated an oral bioavailability of 34-58% and a plasma half-life (T1/2) of 14 hours. In addition, RX-3117 was safe and well tolerated in all subjects throughout the dose range tested. The Investigational New Drug (IND) application for RX-3117 filed in July 2013 has now cleared the 30 day review period by the US Food and Drug Administration (FDA). Rexahn expects to initiate a Phase I clinical trial in cancer patients during the fourth quarter of 2013. Additionally, Rexahn will be exploring potential partnering opportunities with oncology focused pharmaceutical companies. About Prof. Dr. Godefridus J. (Frits) Peters Dr. Peters is head of the Laboratory Medical Oncology of the VU University Medical Center in Amsterdam (the Netherlands). The research of Prof. Peters is focused on translation of preclinical pharmacology of anticancer agents to the clinic. Dr. Peters has published more than 500 peer reviewed articles, review chapters and abstracts in high profile scientific journals. Drug classes studied include antifolates, other antimetabolites, platinum analogs, topoisomerase inhibitors, taxanes and more recently anti-signalling protein kinase inhibitors. He is/was a member of 20 editorial boards, was founder and first president of the Purine and Pyrimidine Society, and is chair of the EORTC-Pharmacology and Molecular Mechanisms Group. About Rexahn Pharmaceuticals, Inc. Rexahn Pharmaceuticals is a clinical stage biopharmaceutical company dedicated to developing best-in-class therapeutics for the treatment of cancer. Rexahn currently has three clinical stage oncology candidates, Archexin®, RX-3117, and SupinoxinTM (RX-5902) and a robust pipeline of preclinical compounds to treat multiple types of cancer. Rexahn has also developed proprietary drug discovery platform technologies in the areas of Nano-Polymer-Drug Conjugate Systems (NPDCS), nano-medicines, 3D-GOLD, and TIMES. For more information, please visit www.rexahn.com. Safe Harbor To the extent any statements made in this press release deal with information that is not historical, these are forward-looking statements under the Private Securities Litigation Reform Act of 1995. Such statements include, but are not limited to, statements about Rexahn's plans, objectives, expectations and intentions with respect to future operations and products and other statements identified by words such as "will," "potential," "could," "can," "believe," "intends," "continue," "plans," "expects," "anticipates," "estimates," "may," other words of similar meaning or the use of future dates. Forward-looking statements by their nature address matters that are, to different degrees, uncertain. Uncertainties and risks may cause Rexahn's actual results to be materially different than those expressed in or implied by Rexahn's forward-looking statements. For Rexahn, particular uncertainties and risks include, among others, the difficulty of developing pharmaceutical products, obtaining regulatory and other approvals and achieving market acceptance; the marketing success of Rexahn's licensees or sublicensees; the success of clinical testing; and Rexahn's need for and ability to obtain additional financing. More detailed information on these and additional factors that could affect Rexahn's actual results are described in Rexahn's filings with the Securities and Exchange Commission, including its most recent annual report on Form 10-K and subsequent quarterly reports on Form 10-Q. All forward-looking statements in this news release speak only as of the date of this news release. Rexahn undertakes no obligation to update or revise any forward-looking statement, whether as a result of new information, future events or otherwise.