A return to normal erectile function with tadalafil once daily after an incomplete response to as-needed PDE5 inhibitor therapy

Abstract

Introduction: An optimal outcome of an erectile dysfunction (ED) treatment is to enable a return to normal erectile function (as defined by an International Index of Erectile Function-Erectile Function [IIEF-EF] domain score ≥ 26). As-needed (PRN) phosphodiesterase type 5 (PDE5) inhibitor treatment does not always result in a return-to-normal erectile function.

Aim: The combined studies evaluated whether treatment with tadalafil once daily would allow men to return to normal erectile function who had less than normal IIEF-EF domain scores while using a maximum dose of a PRN PDE5 inhibitor treatment.

Methods: Men were ≥ 18 years of age, sexually active, reported a ≥ 3-month history of ED, and had been taking the maximum dose of sildenafil citrate, vardenafil, or tadalafil PRN. Randomization to once-daily therapy with tadalafil 2.5 mg to 5 mg (N = 207), tadalafil 5 mg (N = 207), or placebo (N = 209) for 12 weeks followed a 4-week maximum dose PRN PDE5 treatment and 4-week nondrug lead periods. Two identical double-blind, randomized, placebo-controlled studies were conducted; combined results are reported.

Main outcome measure: The main outcome measure was the percentage of subjects with a return-to-normal erectile function (IIEF-EF domain score ≥ 26) when treated with tadalafil once daily compared with placebo.

Results: In subjects not achieving normal erectile function with the maximum dose of a PRN PDE5 inhibitor, a higher percentage of subjects treated with tadalafil had an IIEF-EF domain score ≥ 26 at end point (tadalafil 2.5- to 5-mg group [39%]; tadalafil 5-mg group [40%]) compared with the placebo group (12.1%; P < 0.001). Tadalafil was generally well tolerated and adverse events observed were consistent with previous reports of tadalafil once daily.

Conclusions: Treatment with tadalafil once daily significantly improved erectile function in men with mild to mild-moderate impairments in erectile function following PRN PDE5 inhibitor treatment.

Trial registration: ClinicalTrials.gov NCT01130532.

Keywords: Clinical Trial; Erectile Dysfunction; Oral Therapy; Phosphodiesterase Type 5 Inhibitor; Tadalafil.