Rexahn Pharmaceuticals, Inc. (NYSE Amex: RNN), a clinical stage pharmaceutical company developing and commercializing potential best in class oncology and CNS therapeutics, today announced that it has submitted a Phase IIb protocol to the U.S. Food and Drug Administration (FDA) for the clinical study of Serdaxin for the treatment of major depressive disorder (MDD).

The Phase IIb study will assess Serdaxin’s efficacy as a treatment for major depressive disorder in approximately 300 subjects. The planned double blind, randomized, placebo-controlled trial will be conducted at multiple sites in the U.S. and will measure the change from baseline on the Montgomery-Asberg Depression Rating Scale (MADRS) as the primary efficacy endpoint.

“We look forward to starting this Phase IIb clinical trial and further investigating how Serdaxin’s novel action as a dual serotonin and dopamine enhancer may be able to provide a broader therapeutic effect with fewer side effects compared to currently marketed antidepressants,” said Dr. Chang Ahn, Rexahn’s Chief Executive Officer.

In recent comments made about the promise of Serdaxin, Dr. Michael Thase, Professor of Psychiatry and Chief of the Division of Mood and Anxiety Disorders Treatment and Research Program at the University of Pennsylvania and Chairman of Rexahn’s scientific advisory board in MDD, said, “In my opinion, Serdaxin’s novel mechanism, which targets both serotonin and dopamine, coupled with the promising results of the recent proof of concept study, provide strong support for further clinical development of this well tolerated drug for treatment of depression.”