Next-Generation, Fast-Acting PDE-5 Inhibitor Shows Promise

From The American Urological Association

ATLANTA—The investigational, highly selective, fast-acting, oral phosphodiesterase type 5 (PDE-5) inhibitor avanafil (Vivus) may soon offer a safe and effective alternative to the current armamentarium for men with erectile dysfunction (ED), according to data presented at the 2006 annual meeting of the American Urological Association.

Avanafil has the potential to be taken twice a day for men who desire sexual intercourse more frequently than once daily. And its short half-life of just 90 minutes may reduce the risk of side effects and interactions with other drugs, such as nitrates. Sildenafil (Viagra) and vardenafil (Levitra) have half-lives of 4 hours; the half-life of tadalafil (Cialis) is 17.5 hours.

IMWR

This drug “has a much shorter half-life, and there are some patients who may not want to have the medication effects last a long time. These are patients who may be predisposed to hypertensive vascular disease and want a short-effect, on-demand medication that will provide them with adequate sexual functioning,” investigator Ajay Nehra, MD, professor of urology, Mayo Clinic College of Medicine, Rochester, Minn, told .

This phase 2, multicenter, double-blind, randomized, parallel-design study included 284 men (aged 32-70 years) with mild-to-moderate ED (mean duration, 66.7 months) who were randomly assigned to 12 weeks of avanafil, at doses of 50, 100, 200, or 300 mg, or placebo taken 30 minutes before sexual activity; 87% of the men had used other PDE-5 inhibitors. Thus the study began with a 4-week nontreatment run-in period.

Avanafil was associated with significant dose-related increases in the ability to successfully complete intercourse.

The Table lists the primary study outcomes, including the percentage of successful vaginal penetration (Sexual Encounter Profile [SEP] 2), the percentage of successfully completed sexual intercourse (SEP 3), and erectile function score on the International Index of Erectile Function questionnaire, by treatment groups.

Phase 3 studies are anticipated to start in the latter part of this year.