Rexahn Pharmaceuticals has enrolled the first patient in a Phase IIb clinical trial to evaluate Serdaxin as treatment for major depressive disorder.

The randomised, double blind and placebo-controlled study will enrol up to 300 patients, and will be conducted at 40 sites across the US.

Serdaxin will be administered as an oral, extended release tablet.

Patient enrolment will be conducted through the first half of 2011, with preliminary data expected later in the year.

Rexahn president Rick Soni said that data from Phase IIa study for major depressive disorder suggested that Serdaxin has the potential to improve symptoms of the condition without the side effects commonly associated with current antidepressants.