Effects Of Once-Daily Tadalafil On Erectile Function In Men With Erectile Dysfunction And Signs And Symptoms Of Benign Prostatic Hyperplasia

Main Category: Erectile Dysfunction / Premature Ejaculation
Also Included In: Urology / Nephrology;  Prostate / Prostate Cancer;  Men's health
Article Date: 12 Jul 2009 - 4:00 PST

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UroToday.com - Men with benign prostatic hyperplasia (BPH) often suffer from lower urinary tract symptoms (LUTS; BPH-LUTS) such as urinary frequency, urgency, intermittency, nocturia, straining, incomplete emptying, or weak urinary stream. BPH-LUTS and erectile dysfunction (ED), both highly prevalent conditions in aging men, are frequently associated in the same men, may have common pathophysiological mechanisms, and contribute negatively to quality of life.

Phosphodiesterase type 5 (PDE5) isozymes are considered promising targets for drug intervention in the urogenital tract, and the potential use of PDE5 inhibitors as treatment for both BPH LUTS and ED is of clinical interest. The PDE5 inhibitor tadalafil, currently approved for the treatment of erectile dysfunction and for the treatment of pulmonary arterial hypertension in some geographies, is being studied in men with signs and symptoms of BPH. Tadalafil's 17.5-hour half-life makes it suitable for once-daily therapy.

We report a post hoc analysis of 581 men from a 12-week, randomized, double-blind, placebo-controlled, parallel-group, multinational, dose-finding study of once-daily tadalafil conducted in men with BPH-LUTS. The men included in this analysis were sexually active with a female partner and also had ED, defined as a consistent change in the quality of erection that adversely affected patient satisfaction with sexual intercourse.

We evaluated in these men changes in erectile function (International Index of Erectile Function-Erectile Function [IIEF-EF] domain score), changes in BPH-LUTS measures (International Prostate Symptom Score [IPSS], peak urinary flow rate [Qmax], and postvoid residual volume [PVR]), and safety with tadalafil once daily (2.5 mg, 5 mg, 10 mg, or 20 mg) vs. placebo.

IIEF EF domain score improvements from baseline with once-daily tadalafil were significantly greater throughout the study for all tadalafil groups vs. placebo (all p values ≤0.001). Once-daily tadalafil also improved IIEF-EF domain scores in clinically important subgroups of patients stratified according to age group, body mass index, BPH-LUTS severity, prostate-specific antigen (a surrogate for prostate size), prior α-blocker use, and prior ED therapy, suggesting that once-daily tadalafil may be effective in treating a broad group of men with BPH-LUTS. IPSS improvements from baseline to end point were significantly greater with all tadalafil doses vs. placebo (all p values <0.05). Changes in Qmax and PVR were not clinically meaningful. All doses of once-daily tadalafil were well tolerated, and the most commonly reported treatment-emergent adverse events (headache, back pain, dyspepsia, and myalgia) were consistent with those reported in previous studies of once-daily tadalafil in men with BPH or ED. Tadalafil 5 mg provided the optimal risk-to-benefit profile of the doses studied.

The current study was characterized by a large sample size for each treatment group evaluated, optimizing the opportunity to identify real trends in erectile function improvements. The study design was different from typical studies conducted in the general ED population, in that these men were not required to make a minimum number of sexual intercourse attempts prior to baseline or between study visits. Therefore, the fact that some men attempted sexual intercourse infrequently during the study may have made it more difficult for the IIEF questionnaire to measure the full benefit of once-daily tadalafil in improving erectile function. Despite this limitation, the analyses we performed still showed that once-daily tadalafil is effective in men with ED and signs and symptoms of BPH, with erectile function improvements comparable to those for the general ED population. Therefore, the data support the use of once-daily tadalafil in the population of men with ED and signs and symptoms of BPH.

Future studies will assess whether the effects of once-daily tadalafil on signs and symptoms of BPH are maintained over the long term, and will also evaluate the mechanisms leading to BPH-LUTS improvements with once-daily tadalafil.

Written by Hartmut Porst, MD and Anne M. Wolka, PhD as part of Beyond the Abstract on UroToday.com

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