PDE-5 inhibitors may play a role in BPH, LUTS

September 1, 2007

The therapeutic role of phosphodiesterase-5 (PDE-5) inhibitors could expand to include some patients with BPH and lower urinary tract symptoms.

The larger of two prospective, randomized trials involved 369 men with erectile dysfunction and concomitant lower urinary tract symptoms. The patients, whose mean age was 60 years, had about a 6-year history of erectile dysfunction and a 5-year history of BPH and LUTS, reported first author Kevin McVary, MD, professor of urology at the Northwestern University Feinberg School of Medicine in Chicago.

The patients were randomized to placebo or to sildenafil citrate (Viagra), 50 mg, taken nightly before bedtime or 1 hour before sexual activity. Treatment continued for 12 weeks. The primary endpoints were change in the erectile function (EF) domain score of the International Index of Erectile Function (IIEF), change in the International Prostate Symptom Score (IPSS), and change in maximum urinary flow (Qmax).

Stratification of the data by baseline symptom severity showed that patients with severe LUTS (IPSS ≥20) improved substantially more compared with placebo than did those with moderate symptoms (IPSS 8-19, p=.0619). Among men with severe symptoms at baseline (54% of the cohort), considerably more had transformation to mild (16% vs. 4%) or moderate (57% vs. 36%) symptoms compared with placebo at the end of the study, the researchers found.

"The improvement in IPSS correlated with the IIEF changes," Dr. McVary said. "Patients with more severe symptoms had more improvement, in a sense, because they have more room for change."

However, the lack of improvement in flow rate came as a surprise to investigators, he said.

"Although we didn't have an active comparator, the improvement looks to be comparable to what we might expect when giving alpha-blockers or a 5-alpha-reductase inhibitor," Dr. McVary noted.

Potential mechanisms involved in the coexistence of LUTS and erectile dysfunction and absence of flow improvement include a pelvic deficiency in nitric oxide. Other possibilities are an effect on bladder compliance, modulation of PDE-5 effects on sensory innervation, and perhaps a change in pelvic flow affecting ischemia.

Quality of life improved

Results of a German study provided additional evidence of a possible role for PDE-5 inhibitors in the treatment of BPH and LUTS. The study involved 222 men with moderate to severe urinary symptoms, randomized to vardenafil, 10 mg twice daily, or placebo for 8 weeks. The primary endpoints were change in IPSS, UROLIFE (a BPH quality of life questionnaire), and the EF domain of the IIEF.

Baseline IPSS averaged 16.8 in both groups. At the end of the study, vardenafil patients had a mean improvement of 5.9 compared with 3.6 for the placebo group (p=.0013), reported Christian Stief, MD, professor of urology at Ludwig-Maximilians University in Munich. Vardenafil also led to significantly greater improvement in the IPSS subscales for obstructive symptoms (3.2 vs. 1.9, p=.0081) and irritative symptoms (2.6 vs. 1.7, p=.0017).

The vardenafil group also had significantly greater improvement on the UROLIFE questionnaire (p<.0001) and on the subscales for activity and perceived sexual life. IIEF scores improved by an average of 7.5 with vardenafil and 1.5 with placebo (p=.0001).