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Sexual
Dysfunction
ZoraxelTM is a CNS-based sexual dysfunction drug that is being developed to treat Erectile Dysfunction (ED), and has extensive safety in humans. ZoraxelTM is a dual serotonin and dopamine enhancer in the brain, where these neurotransmitters play a key role in three phases (sexual motivation-arousal, erection and release) of sexual activity. ZoraxelTM may be the first ED drug to affect all three phases of the sexual activity. In preclinical studies and animal models, ZoraxelTM significantly improved sexual performance and suggested positive behavioral effects on sexual motivation and arousal.
Erectile dysfunction (ED) is defined as the consistent inability to attain and maintain an erection sufficient for satisfactory sexual intercourse. Erectile problems may be due to psychogenic causes (e.g., depression or stress) or 'organic' causes. In many cases, both organic and psychogenic factors are present. The launch of Viagra in 1998 as the first orally available phosphodiesterase (PDE)-5 inhibitor established a new standard of care for ED, and pioneered the ED market. Cialis and Levitra were subsequently launched in 2003 as second-generation PDE-5 inhibitor drugs. Beyond the leading PDE-5 inhibitors, there is currently no single class of ED drugs to dominate the ED pipeline. An estimated 30% of US men are refractory to the leading PDE-5 inhibitor drugs, which work peripherally and mechanically. Certain segments of the ED patient population that respond less to PDE-5 inhibitors include diabetics, obese or post-surgical prostatectomy or coronary risk patients. PDE-5 inhibitors may have significant drawbacks of cardiovascular risks and other side effects (e.g., priapism, severe hypotension, myocardial infarction, ventricular arrhythmias, sudden death and increased intraocular pressure).
Rexahn is developing ZoraxelTM as an orally available drug that has extensive safety and addresses specific features of male ED. Unlike the PDE-5 inhibitors working at the peripheral blood vessel and only mechanically affecting erection, ZoraxelTM is centrally acting and works in the brain and affects all three functions of sexual activity, i.e. sexual arousal, erection, and release. ZoraxelTM is well tolerated and appears to lack serious side effects associated with PDE-5 inhibitors. ZoraxelTM may be superior to PDE-5 inhibitors, and offer clinical benefits over dopamine agonists. Phase II trials are ongoing for 2009 for ZoraxelTM.
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