We calculated the change from baseline in IPSS total score (primary), storage and voiding subscores, quality of life (QoL) due to urinary symptoms, and Q(max). Responders were defined on the basis of IPSS and Q(max) by a decrease of ≥25% and an increase of ≥30% from baseline, respectively.
RESULTS AND LIMITATIONS: The change from baseline in the IPSS total score with
silodosin and
tamsulosin was significantly superior to that with placebo (p<0.001): difference active placebo of -2.3 (95% confidence interval [CI], -3.2, -1.4) with
silodosin and -2.0 (95% CI,-2.9, -1.1) with
tamsulosin. Responder rates according to total IPSS were significantly higher (p<0.001) with
silodosin (66.8%) and
tamsulosin (65.4%) than with placebo (50.8%). Active treatments were also superior to placebo in the IPSS storage and voiding subscore analyses, as well as in QoL due to urinary symptoms. Of note, only
silodosin significantly reduced
nocturia versus placebo (the change from baseline was -0.9, -0.8, and -0.7 for
silodosin,
tamsulosin, and placebo, respectively; p=0.013 for
silodosin vs placebo). An increase in Q(max) was observed in all groups. The adjusted mean change from baseline to end point was 3.77 ml/s for
silodosin, 3.53 ml/s for
tamsulosin, and 2.93 ml/s for placebo, but the change for
silodosin and
tamsulosin was not statistically significant versus placebo because of a particularly high placebo response (
silodosin vs placebo: p=0.089;
tamsulosin vs placebo: p=0.221). At end point, the percentage of responders by Q(max) was 46.6%, 46.5%, and 40.5% in the
silodosin,
tamsulosin, and placebo treatment groups, respectively. This difference was not statistically significantly (p=0.155
silodosin vs placebo and p=0.141
tamsulosin vs placebo). Active treatments were well tolerated, and discontinuation rates due to adverse events were low in all groups (2.1%, 1.0%, and 1.6% with
silodosin,
tamsulosin, and placebo, respectively). The most frequent adverse event with
silodosin was a reduced or absent ejaculation during orgasm (14%), a reversible effect as a consequence of the potent and selective α(1A)-adrenoreceptor antagonism of the
drug. The incidence was higher than that observed with
tamsulosin (2%); however, only 1.3% of
silodosin-treated patients discontinued treatment due to this adverse event.
CONCLUSIONS: ClinicalTrials.gov Identifier NCT00359905.