A potential addition to the treatment options for erectile dysfunction (ED) is entering Phase III trials in the United States. Udenafil, a new long-acting drug under development for ED, will be evaluated in 80 sites throughout the country.
Erectile dysfunction, an inability to achieve or sustain an erection suitable for sexual intercourse, affects approximately 18 million men in the United States. Current drug treatment options for this condition now include a category of drugs called phosphodiesterase type 5 (PDE-5) inhibitors. These drugs are Cialis® (tadalafil), Levitra® (vardenafil), and Viagra® (sildenafil). Udenafil is also a PDE-5 inhibitor.
Dong-A PharmTech Co. Ltd, announced that its US partner, Warner Chilcott plc, has started two Phase III trials for the new PDE-5 drug. The randomized, double-blind, placebo-controlled trials will enroll approximately 1,120 subjects who have erectile dysfunction. Dong-A PharmTech hopes to complete these Phase III trials as well as other trials in the European Union and other major markets within two years. The pharmaceutical company also plans to initiate Phase 2b clinical trials that will evaluate the safety and efficacy of udenafil for treatment of benign prostatic hyperplasia and pulmonary arterial hypertension.
According to a clinical practice guideline issued by the American College of Physicians in an October 19, 2009 news release regarding treatment of ED, clinicians are urged to use PDE-5 drugs for men with erectile dysfunction unless they are taking nitrates.
A comparison among the different PDE-5 drugs, according to the ACP news release, indicates that “the evidence is insufficient to compare the effectiveness or adverse effects of different PDE-5 inhibitors for the treatment of ED because there were only a few head-to-head trials,” noted guideline lead author Dr. Amir Qaseem, who is also senior medical associate with the ACP.
Udenafil was approved for treatment of erectile dysfunction in Korea in November 2005 under the trade name Zydena®. The drug was also approved for marketing in Russia in July 2008. If udenafil is approved in the United States, it will compete with Cialis, Levitra, and Viagra for treatment of erectile dysfunction. According to an analysis by the American College of Physicians of 130 studies that evaluated PDE-5 inhibitors alone or in combination, treatment with the currently available drugs resulted in statistically significant and clinically relevant improvements in sexual and erectile function in men with ED, regardless of the cause (e.g., depression, diabetes, prostate cancer).