Avanafil in the Treatment of Erectile Dysfunction Following Bilateral Nerve-Sparing Radical Prostatectomy

Avanafil is a rapidly-acting, highly specific PDE5 inhibitor under investigation for the
treatment of erectile dysfunction (ED).

The dose selection and timing of medication ingestion in relation to attempted sexual
activity in this study is based on data from pre-clinical pharmacology studies and results
of Phase 1 and 2 clinical trials examining the pharmacokinetics, pharmacodynamics, safety,
and tolerability of avanafil at doses of 50, 100, 200, and 300 mg. On the basis of these
results, 100 and 200 mg doses of avanafil are expected to define the range of doses that are
effective and well-tolerated for treatment of ED in this population. This study will
evaluate the safety and efficacy of these two dose levels of avanafil in the treatment of ED
in a population of men with ED following bilateral nerve-sparing radical prostatectomy.

This is a Phase 3, multicenter, randomized, double-blind, placebo-controlled,
parallel-design, three-arm trial to assess the safety and efficacy of avanafil in the
treatment of mild-to-severe ED in men following bilateral nerve-sparing radical
prostatectomy.

Subjects will complete a 4-week non-treatment run-in period during which they will maintain
a diary of all attempts at sexual intercourse. At the conclusion of the run-in period,
subjects with a 50% or greater failure rate in maintaining an erection for a sufficient
duration to allow successful intercourse, a score of 5-25 (inclusive) on the erectile
function (EF) domain of the IIEF questionnaire, and who made at least 4 attempts at sexual
intercourse during the run-in period will be eligible for randomization to one of the three
treatment arms: placebo, avanafil 100 mg, or avanafil 200 mg. Randomized subjects will
then complete a 12 week treatment period during which they will return to the site at 4 week
intervals for evaluation and to obtain additional study medication.

All subjects will be instructed to administer study drug about 30 minutes prior to
initiation of sexual activity and to complete a diary entry containing treatment information
and results after each use of the drug. Subjects may take up to 2 doses of study drug
within a 24-hour period provided that the doses are separated by at least 12 hours.