A Phase 3, Placebo Controlled Study of the Safety and Efficacy of Avanafil for the Treatment of Erectile Dysfunction After Nerve Sparing Radical Prostatectomy

Purpose: We evaluated the safety and efficacy of 100 and 200 mg avanafil for the treatment of adult males with erectile dysfunction after bilateral nerve sparing radical prostatectomy. Materials and Methods: This was a double-blind, placebo controlled, parallel group, phase 3 study in males age 18 to 70 years with a history of erectile dysfunction of 6 months or more after bilateral nerve sparing radical prostatectomy. Patients were randomized to 100 or 200 mg avanafil or placebo (taken 30 minutes before sexual activity) for 12 weeks. Primary end points included successful vaginal insertion (Sexual Encounter Profile [SEP] question 2), successful intercourse (SEP3) and change in score on the erectile function domain of the International Index of Erectile Function (IIEF-EF) questionnaire. Results: A total of 298 patients were randomized and 84.6% completed the study. At baseline 16.1% were age 65 years or older and 71.5% had severe erectile dysfunction (mean overall IIEF-EF domain score 9.2). After 12 weeks there were significantly greater increases in SEP2 and SEP3 and change in mean IIEF-EF domain score with 100 and 200 mg avanafil vs placebo (p < 0.01). Following dosing with avanafil 36.4% (28 of 77) of sexual attempts (SEP3) at 15 minutes or less were successful vs 4.5% (2 of 44) for placebo (p < 0.01). Avanafil was generally well tolerated. No serious adverse events were reported and fewer than 2% of patients discontinued the study due to an adverse event. Conclusions: Avanafil in 100 and 200 mg doses was effective and well tolerated in improving erectile function after prostatectomy. Results suggest a rapid onset of action and sustained duration of effect, with all 3 primary end points being achieved at both dose levels.