RX-3117 is a small molecule antimetabolite for the treatment of solid tumors.

“Preclinical studies demonstrate RX-3117 to have exciting anti-cancer properties, and we look forward to moving this compound into clinical development,” said Rick Soni, President and COO of Rexahn. “We will continue to develop RX-3117, which has potential therapeutic applications in a broad range of cancers, including colon, lung and pancreatic cancer.”

In September 2009, Rexahn entered into a commercialization and development agreement with Teva Pharmaceutical Industries Limited for RX-3117. Under the agreement, Rexahn is eligible to receive development, regulatory and sales milestone payments, as well as royalties on net sales worldwide.

About RX-3117
RX-3117 is a small molecule, new chemical entity (NCE), nucleoside compound that inhibits DNA methyltransferase, a cyclin-dependent kinase, and DNA synthesis. Potential indications of RX-3117 are solid tumors including colon, lung and pancreatic cancers. RX-3117 has demonstrated its ability to overcome cancer drug resistance in cancer cells, in particular, gemcitabine-resistance in the human lung cancer cell. The US and European patent issued for RX-3117 claims composition of matter, synthesis and methods (2008 and 2010, respectively).

About Rexahn Pharmaceuticals, Inc.
Rexahn Pharmaceuticals is a clinical stage pharmaceutical company dedicated to developing and commercializing first in class and market leading therapeutics for cancer, CNS disorders, sexual dysfunction and other unmet medical needs. Rexahn currently has three drug candidates in Phase II clinical trials, Archexin®, Serdaxin®, and Zoraxel™, and a robust pipeline of preclinical compounds to treat multiple cancers and CNS disorders. Rexahn also operates key R&D programs of nano-medicines, 3D-GOLD, and TIMES drug discovery platforms. 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.

“Rexahn has made the decision to focus in the near term on our oncology program after evaluating how best to apply our resources in order to realize near term value appreciation for our shareholders,” stated Dr. Chang Ahn, Chairman and CEO of Rexahn. “We have sufficient funding to carry the company forward through 2012. The accelerated development of the company’s potent anti-cancer compounds will enable Rexahn to drive short term value while supporting our longer term competitive position.”

Dr. Ahn added, “Though we were disappointed in the Serdaxin Phase IIb results that we announced in November 2011, we are pleased with the important progress made during the year in our oncology programs. Due to this progress we are in a position to achieve several key milestones in 2012. In the next 12 to 18 months, we expect to substantially add to and advance our oncology pipeline by taking multiple compounds into human trials, as well as to aggressively seek partnerships for several of our oncology assets.”

Rexahn Goals for 2012:

• Pursue new partnerships. Rexahn actively seeks to form new product collaborations in addition to its partnership with Teva Pharmaceutical Industries. This could include out-licensing or co-developing Rexahn’s promising oncology assets in order to expedite clinical development, scientific platform alliances to maximize the utility of the Company’s three powerful discovery platforms, and research collaborations to further expand the pipeline.

• Advance clinical program for RX-3117. In September 2009, Rexahn entered into a commercialization and development agreement with Teva Pharmaceutical Industries Limited for RX-3117. Under the agreement, Rexahn is eligible to receive development, regulatory, and sales milestone payments, as well as royalties on net sales worldwide. In the first quarter of 2012, Rexahn expects to initiate an exploratory first-in-human Phase I clinical trial for RX-3117. RX-3117 has shown potent anti-tumor effects in xenograft human tumor models. Preclinical studies have revealed the compound’s high bioavailability and good safety profile, which is the current first-line therapy for pancreatic and other cancers.

• Initiate clinical program for RX-5902. In the second quarter of 2012, Rexahn expects to file an Investigational New Drug application for a first-in-human clinical trial for RX-5902, an orally available, first-in-class inhibitor of p68 RNA helicase for the treatment of various solid tumors, in particular melanoma. Preclinical studies have demonstrated the inhibition of tumor growth and enhanced survival in in vivo animal xenograft models, synergistic action when combined with known anticancer agents, and potent anti-growth activity in drug-resistant cancer cells. A unique, nano-based clinical oral formulation has been developed.

• Complete clinical trial of Archexin to treat pancreatic cancer. Rexahn expects to report the results of its Phase II clinical trial of Archexin in pancreatic cancer in the third quarter of 2012. Archexin is a first in class, potent Akt protein kinase inhibitor with the potential to inhibit cancer cell survival and proliferation, angiogenesis, and drug resistance. Archexin has FDA Orphan drug designation for five different cancer types, including renal cell carcinoma, glioblastoma, pancreatic, stomach, and ovarian cancers.

• Initiate clinical program for RX-8243. Rexahn expects to file an Investigational New Drug application in late 2012 or early 2013 for RX-8243, a small molecule inhibitor of Ark 1 kinase and other Ser/Thr kinase for the treatment of various solid tumors. RX-8243 showed better efficacy than paclitaxel in the paclitaxel-insensitive colon xenograft model and potent anti-growth activity in drug-resistant cancer cells.

• Evaluate options for CNS program (Serdaxin and Zoraxel). Rexahn is exploring options for further development of Serdaxin and Zoraxel, including out-licensing or divesture of the compounds, entering a co-development partnership, and continuation of clinical trials in Major Depressive Disorder for Serdaxin and Erectile Dysfunction for Zoraxel.

• Continue new CEO search. Rexahn continues its search for a Chief Executive Officer (CEO) to succeed Dr. Chang Ahn, who currently serves as both CEO and Chief Science Officer (CSO) until a new CEO is in place. The company expects to name a new CEO in early 2012.

About Rexahn Pharmaceuticals, Inc.
Rexahn Pharmaceuticals is a clinical stage pharmaceutical company dedicated to developing and commercializing first in class and market leading therapeutics for cancer, CNS disorders, sexual dysfunction and other unmet medical needs. Rexahn currently has three drug candidates in Phase II clinical trials, Archexin®, Serdaxin®, and Zoraxel™ and a robust pipeline of preclinical compounds to treat multiple cancers and CNS disorders. Rexahn also operates key R&D programs of nano-medicines, 3D-GOLD, and TIMES drug discovery platforms. 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.

“These results contradict findings from previous studies of Serdaxin in depression, which is disappointing. The Phase IIa study of Serdaxin demonstrated in a subset of severely depressed patients a statistically significant reduction in MADRS scores compared to placebo at the 5 mg dose,” said Dr. Chang Ahn, Chief Executive Officer of Rexahn. “Given the result of this latest trial we will closely evaluate the Serdaxin clinical program and possible paths forward. Additionally, we will continue to advance other CNS and oncology clinical programs and explore our robust pipeline to support and create value for the company.”

Dr. Michael Thase, Chairman of the Depression Scientific Advisory Board of Rexahn, stated, “The results of this Phase II trial should be viewed within the historical context of depression clinical trials. The history of drug development in depression has one dominant theme – a notoriously high placebo effect. Six of the blockbuster antidepressant drugs approved between 1987 and 1999 had altogether undergone forty-two clinical trials, many of which were negative. With only one larger clinical trial completed, it may be premature to discount Serdaxin’s potential clinical value.”

The Phase II study was conducted at 44 centers across the United States and enrolled 314 patients with a history of major depressive disorder. The primary endpoints were safety and efficacy, as measured by a change in MADRS score.  The trial consisted of a screening period during which the patients were selected for their medical condition using DSM IV criteria and a MADRS score of 26 or higher as assessed by central raters.

About Rexahn Pharmaceuticals, Inc.

Rexahn Pharmaceuticals is a clinical stage pharmaceutical company dedicated to developing and commercializing first in class and market leading therapeutics for cancer, CNS disorders, sexual dysfunction and other unmet medical needs. Rexahn currently has three drug candidates in Phase II clinical trials, Archexin^®, Serdaxin^®, and Zoraxel™ – all potential best in class therapeutics – and a robust pipeline of preclinical compounds to treat multiple cancers and CNS disorders.  Rexahn also operates key R&D programs of nano-medicines, 3D-GOLD, and TIMES drug discovery platforms.  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.

This patent covers several new isoquinolinamine compounds and their pharmaceutical composition and method for producing an anti-tumor effect.  The patent specifically covers Rexahn’s compound RX-8243, currently in pre-clinical development.

In a recently published study in Bioorganic & Medicinal Chemistry Letters [20:5277-5281, 2010], RX-8243 exhibited potent anti-tumor properties in several cancer cell lines, as well as in paclitaxel-resistant human colorectal xenograft models. RX-8243 also demonstrated a synergistic cytotoxic effect when combined with several known cancer drugs against human cancer cells.

Rick Soni, President of Rexahn, commented, “This new US patent for arylisoquinolinamine compounds is an important step in the development of RX-8243 and further strengthens our global intellectual property position around our oncology pipeline.”

About Rexahn Pharmaceuticals, Inc.

Rexahn Pharmaceuticals, Inc. is a clinical stage pharmaceutical company dedicated to developing and commercializing first in class and market leading therapeutics for cancer, CNS disorders, sexual dysfunction and other unmet medical needs. Rexahn currently has three drug candidates in Phase II clinical trials, Archexin®, Serdaxin®, and Zoraxel™ – all potential best in class therapeutics – and a robust pipeline of preclinical compounds to treat multiple cancers and CNS disorders.  Rexahn also operates key R&D programs of nano-medicines, 3D-GOLD, and TIMES drug discovery platforms.  For more information about Rexahn, 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 U.S. 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 press release speak only as of the date of this press release. Rexahn undertakes no obligation to update or revise any forward-looking statement, whether as a result of new information, future events or otherwise.

Rockville, Md., October 3, 2011 – Rexahn Pharmaceuticals, Inc. (NYSE Amex: RNN), a clinical stage pharmaceutical company developing and commercializing potential best in class oncology and CNS therapeutics, today announced the publication of a peer reviewed study in Neuroscience Letters that validates the mechanism of action of clavulanic acid, the active compound in Serdaxin^®, the company’s lead CNS drug currently in Phase II clinical development for major depressive disorder.

The published study, “Clavulanic acid increases dopamine release in neuronal cells through a mechanism involving enhanced vesicle trafficking,” shows that clavulanic acid enhances release of neurotransmitters such as dopamine in the brain cell by interacting with key proteins for vesicle trafficking and fusion.

“This study is significant because it confirms at the molecular and cellular levels how Serdaxin enhances the release of neurotransmitters in the brain. Previous studies demonstrated the release of serotonin and dopamine in the brain by clavulanic acid in live animals. These results strongly support that Serdaxin’s CNS effects may be due to an enhanced release of the dual neurotransmitters, called as the SERDA mechanism.” said Dr. Chang Ahn, Chairman and CEO of Rexahn.

Dr. Ahn elaborated, “Because the effectiveness of currently marketed therapies that modulate serotonin reuptake is significantly limited, there exists very strong therapeutic needs for depression patients who are non-responders, are relapsed, or are non-compliant due to adverse reactions of those therapeutics. Serdaxin positions itself to address these therapeutic and safety needs as the first SERDA antidepressant with excellent safety profile.”

Dr. Michael Thase, Chairman of the Depression Scientific Advisory Board of Rexahn, said, “This study illustrates that clavulanic acid may have important effects on monoaminergic neurotransmission, that are the result of interaction with vesicle trafficking and fusion through a novel mechanism involving Munc18 and Rab proteins. Enhancing the release of both dopamine and serotonin to physiological levels in the brain may prove to have novel therapeutic implications for those who suffer from major depressive disorder and other neurological disorders.”

About Rexahn Pharmaceuticals, Inc.

Rexahn Pharmaceuticals is a clinical stage pharmaceutical company dedicated to developing and commercializing first in class and market leading therapeutics for cancer, CNS disorders, sexual dysfunction and other unmet medical needs. Rexahn currently has three drug candidates in Phase II clinical trials, Archexin®, Serdaxin®, and Zoraxel™ – all potential best in class therapeutics – and a robust pipeline of preclinical compounds to treat multiple cancers and CNS disorders.  Rexahn also operates key R&D programs of nano-medicines, 3D-GOLD, and TIMES drug discovery platforms.  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.