ROCKVILLE, Md., Jan. 6, 2015 (GLOBE NEWSWIRE) -- Rexahn Pharmaceuticals, Inc. (NYSE MKT:RNN), a clinical stage biopharmaceutical company developing best-in-class therapeutics for the treatment of cancer, today announced the online publication of preclinical results for RX-3117 in the peer reviewed medical journal, Anticancer Research, in an article titled, "A Novel Cytidine Analog, RX-3117, Shows Potent Efficacy in Xenograft Models, Even in Tumors that are Resistant to Gemcitabine". The article was coauthored by Dr. G.J. Peters of the VU University of The Netherlands and Rexahn scientists.
In this study, the efficacy of orally administered RX-3117 was examined in nine different human tumor Xenograft models that had differing degrees of resistance to gemcitabine. In the four high gemcitabine resistant models gemcitabine treatment resulted in 0% to 30% tumor growth inhibition, whereas oral treatment with RX-3117 induced tumor growth inhibition between 62% to 100%. RX-3117 was also evaluated in a primary low passage Champions Tumorgraft™ model derived from biopsy samples from pancreatic cancer patients with known resistance to gemcitabine. In this model, RX-3117 produced a 76% inhibition of tumor growth, as compared to gemcitabine which had tumor growth inhibition of 38%.
Dr. Staffan Eriksson, MD, PhD, Professor, Department of Anatomy, Physiology and Biochemistry at The Swedish University of Agricultural Sciences commented, "The Champions Tumorgraft™ model used cancer cells, and their microenvironment, taken from individual cancer patients and then transplanted directly into a mouse Xenograft model, making the results potentially more predictive for the outcome of clinical trials. The fact that RX-3117 was active against cells partially resistant to gemcitabine makes these results very promising for future drug development efforts which may be of great benefit to many cancer patients."
Peter D. Suzdak, Ph.D., Rexahn's Chief Executive Officer, commented, "The ability of RX-3117 to inhibit the growth of gemcitabine resistant human cancers cells is very exciting. Moreover, the pronounced anti-tumor effects of RX-3117 in the Champions Tumorgraft™ model are of particular importance because the cancer cells used in this model are derived directly from biopsies taken from pancreatic cancer patients who have shown gemcitabine resistance. Resistance to the anti-cancer effects of gemcitabine represents a major clinical issue in the treatment of cancer patients. Up to 40% of cancer patients receiving one or more cycles of gemcitabine rapidly become resistant to its anti-cancer activity. Based on study results to date, both preclinical and clinical, we believe RX-3117 holds the potential to be used for the treatment of tumors that do not respond to gemcitabine."
About RX-3117
RX-3117 is a novel small molecule anti-metabolite that is incorporated into DNA or RNA of cells and inhibits both DNA and RNA synthesis which induces apoptotic cell death of tumor cells. RX-3117 also mediates the downregulation 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, RX-3117 still retains its full anti-tumor activity in human cancer cell lines made resistant to the anti-tumor effects of gemcitabine. 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 56% 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.
Rexahn initiated a Phase Ib clinical trial of RX-3117 in cancer patients with solid tumors in January 2014. The Phase Ib clinical trial is a multi-center dose-escalation study that will evaluate the safety, tolerability, dose-limiting toxicities and maximum tolerated dose (MTD) of RX-3117 in patients with solid tumors. Secondary endpoints will include characterizing the pharmacokinetic profile of RX-3117 and evaluating the preliminary anti-tumor effects of RX-3117. Patient enrollment has been completed in five dose groups (30, 60, 100, 150 and 200 mg) and patients are now enrolling for the sixth dose group (500 mg). The MTD of RX-3117 has not yet been achieved. The Company expects to complete patient enrollment of the RX-3117 Phase Ib clinical trial early in 2015.
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 cash flow requirements, future operations and products, enrollments in clinical trials, the path of clinical trials and development activities, 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 success and design 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.