Utrech University Study Indicates that Rexahn's Zoraxel(TM) Could Become New-Class of Drug for Treating Sexual Dysfunction

More evidence suggests Zoraxel as potential treatment for drug related and non-drug related sexual dysfunction

ROCKVILLE, Md.--(BUSINESS WIRE)-- Rexahn Pharmaceuticals, Inc. (NYSE Amex: RNN), today announced the results of an animal study that further demonstrates Zoraxel as a potential new-class of therapeutic for the effective treatment of sexual dysfunction.

The research carried out at the Department of Psychopharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, The Netherlands, discovered that beta-lactamase inhibitor clavulanic acid, the primary compound in Rexahn's Phase II drug candidate Zoraxel(TM), produced a remarkable increase in the sexual activity in rats, offering important insight for how Zoraxel may positively affect human sexual behavior.

The study (published on-line in the European Journal of Pharmacology on March 11, 2009) "Clavulanic acid stimulates sexual behaviour in male rats", found that Zoraxel exerts strong pro-sexual effects in male rats, an effect amplified after 14 days of treatment.

Of note, the study suggests that Zoraxel improves sexual function in both drug related and non-drug related sexual dysfunction.

"Many psychotropics, especially antidepressants and selective serotonin reuptake inhibitors (SSRI's) are commonly associated with unwanted sexual side effects. Sexual disturbances include libido, erection and orgasm problems. This study reveals further evidence that Zoraxel can be an effective treatment for drug related and non-drug related sexual dysfunction, and is capable of improving sexual function with minimal side-effects," said Doeg Joong Kim, Sr. Director of R&D in Rexahn.

"This study further validates Zoraxel as having the potential to become the first therapeutic capable of treating sexual dysfunction without causing serious negative physiological or behavior effects," added Chang Ahn, Chief Executive Officer of Rexahn. "This is because Zoraxel acts on the central nervous system (the brain), which is responsible for controlling all three phases of sexual function. This is in sharp contrast to all currently marketed therapeutics that only target end organ erectile function and come with serious adverse reactions."

About Zoraxel

Zoraxel is being developed as an orally administered tablet for on-demand use, and is one of three compounds being developed by Rexahn as a part of the Company's drug pipeline. ZoraxelTM has a well established and excellent safety record in humans and appears to lack severe side effects associated with standard of care phosphodiesterase (PDE-5) inhibitor ED drugs, such as priapism, severe hypotension, myocardial infarction, sudden death, increased intraocular pressure and sudden hearing loss. ZoraxelTM is a centrally acting, dual enhancer of neurotransmitters in the brain, whereas PDE-5 inhibitors only target end organ erectile function, and work in peripheral blood vessels. In preclinical animal models, ZoraxelTM has significantly improved all three functions of sexual activity, i.e. sexual arousal, erection, and release, and may be a more effective ED treatment for patients who are responsive or unresponsive to PDE-5 inhibitors.

About Rexahn Pharmaceuticals, Inc.

Rexahn Pharmaceuticals is a clinical stage pharmaceutical company dedicated to commercializing first in class and market leading therapeutics for cancer, CNS disorders, sexual dysfunction and other unmet medical needs. For more information please visit www.rexahn.com

Safe Harbor

This press release contains forward-looking statements. Rexahn's actual results may differ materially from anticipated results, and expectations expressed in these forward-looking statements, as a result of certain risks and uncertainties, including Rexahn's lack of profitability, and the need for additional capital to operate its business to develop its product candidates; the risk that Rexahn's development efforts relating to its product candidates may not be successful; the possibility of being unable to obtain regulatory approval of Rexahn's product candidates; the risk that the results of clinical trials may not be completed on time or support Rexahn's claims; demand for and market acceptance of Rexahn's drug candidates; Rexahn's reliance on third party researchers and manufacturers to develop its product candidates; Rexahn's ability to develop and obtain protection of its intellectual property; and other risk factors set forth from time to time in our filings with the Securities and Exchange Commission. Rexahn assumes no obligation to update these forward-looking statements.

    Source: Rexahn Pharmaceuticals, Inc.

Released May 12, 2009