Avanafil is a potent and selective inhibitor of phosphodiesterase type 5 (PDE5). Inhibition of this enzyme prevents the breakdown of cyclic guanosine monophosphate (cGMP), resulting in smooth muscle relaxation and allowing inflow of blood into the penile tissues, producing an erection.1
The efficacy and safety of avanafil were assessed in three phase III, double-blind, randomised studies, in which 1,168 patients self-administered avanafil 50mg, 100mg or 200mg 30 minutes before initiating sexual activity with adjustments in dosage based on individual response.1
The primary outcome measure was assessed by three co-primary endpoints:2,3,4
- Sexual Encounter Profile (SEP) question 2, the change in the percentage of sexual attempts in which men were able to insert the penis into the partner’s vagina
- SEP question 3, the change in the percentage of sexual attempts in which men were able to maintain an erection of sufficient duration to have successful intercourse
- change in erectile function (EF) domain of the International Index of Erectile Dysfunction (IIEF) questionnaire.
General population with ED
In first study, 646 patients with mild to severe erectile dysfunction (ED) received avanafil or placebo for a 12-week period. Significant improvements were observed for all endpoints with all three doses of avanafil compared with placebo (p<0.001).2
Treatment with avanafil produced significant improvements in SEP3 from baseline, with 27% of sexual attempts in patients receiving placebo resulting in successful intercourse compared with 41% for avanafil 50mg and 57% for avanafil 100mg or 200mg. The 50mg dose of avanafil was inferior to the 100mg and 200mg doses (p<0.0001); there was no significant difference between the 100mg and 200mg doses (p=0.8198).2
All avanafil doses produced an improvement in IIEF-EF domain score compared with placebo. Again, the difference between avanafil 100mg and 200mg was not significant (p=0.1366).2
In further analysis, 300 sexual attempts were made within 15 minutes of dosing. Of these attempts, 64−71% were successful in the avanafil group compared with 27% in the placebo group.2
ED following radical prostatectomy
The second study assessed the safety and efficacy of avanafil in 298 patients with ED following bilateral nerve-sparing radical prostatectomy. At the end of the 12-week treatment period, patients showed an improvement in IIEF-EF domain score of 40% with 100mg avanafil and 55% with 200mg avanafil, compared with 1% for placebo.3
Significant increases in SEP2 and SEP3 with avanafil 100mg or 200mg versus placebo were also observed (p<0.01) and patients had higher rates of successful sexual attempts within 15 minutes when taking avanafil (36.4%) compared with placebo (4.5%).3
Patients with type I or II diabetes
Similar results were seen in the third study in men with type I or II diabetes. The mean percentage of attempts resulting in successful intercourse was 34% and 40% for the 100mg and 200mg avanafil groups, respectively, compared with 21% for the placebo group (p<0.001 for both comparisons).4
Throughout all trials, statistically significant improvements in all primary efficacy outcomes were observed for all three doses of avanafil compared with placebo. These were maintained with long-term treatment.1
All doses of avanafil were well tolerated. The most commonly reported adverse effects were headache, flushing and nasal congestion.1–4
The recommended dose of avanafil is 100mg approximately 30 minutes before sexual activity. The dose may be increased to a maximum of 200mg or decreased to 50mg, dependent on individual efficacy and tolerability. The maximum recommended dosing frequency is once daily.1
- Spedra Summary of Product Characteristics, January 2014.
- Goldstein I et al. J Sex Med 2012; 9: 1122−33.
- Mulhall JP et al. J Urol 2013; 189: 2229−36.
- Goldstein I et al. Mayo Clin Proc 2012; 87: 843−52.
Further information: Menarini