Unlike other PDE5 inhibitors, avanafil is highly selective for PDE5 and does not significantly inhibit other PDE isoenzymes.
Dr. Irwin Goldstein from Alvarado Hospital, San Diego, California and colleagues compared the safety and efficacy of 3 dose levels of avanafil (50 mg, 100 mg, and 200 mg) with placebo in a phase 3 trial of 646 men with mild to severe erectile dysfunction.
All 3 doses of avanafil proved superior to placebo in improving the percentage of sexual attempts in which men were able to insert the penis into their partner’s vagina and in which they were able to maintain an erection of sufficient duration to have successful intercourse (the co-primary efficacy end points).
By the end of the 12-week treatment period, the placebo group experienced a 27% improvement in successful sexual attempts, compared with 41% in the avanafil 50-mg treatment group and 57% in the avanafil 100- and 200-mg treatment groups.
Around two-thirds of sexual attempts made within 15 minutes of avanafil dosing were successful, and up to 83% (depending on avanafil dose) attempts occurring beyond 6 hours after dosing were successful, compared with about a quarter of attempts at both time points with placebo.
All 3 avanafil treatment groups showed significant improvements relative to placebo in the International Index of Erectile Function (IIEF) erectile function domain score and in the individual domains of the IIEF, including orgasmic function, sexual desire, intercourse satisfaction, and overall satisfaction.
Treatment with avanafil was generally well tolerated, and there were no drug-related serious adverse events in the study.
“The improvement in sexual function, tolerability, lack of restrictions relating to alcohol, food, or previous PDE5-inhibitor therapy, coupled with the rapid onset of action and durability of effect, make avanafil a viable candidate for on-demand treatment of erectile dysfunction,” the researchers conclude.
On September 1, 2011, Vivus announced “that the U.S. Food and Drug Administration (FDA) has accepted for review the company’s new drug application (NDA) for its investigational drug candidate, avanafil, for the treatment of erectile dysfunction (ED). The target date for the FDA to complete its review of the avanafil NDA is April 29, 2012.”
Four of the authors were employees of Vivus, Inc., which sponsored the study, and all of the other authors had received grants and research support and/or had served as a consultant or advisor for Vivus.
Journal of Sexual Medicine, 16 January 2012