Dutasteride improves objective and subjective disease measures in men with benign prostatic hyperplasia and modest or severe prostate enlargement.

Purpose: We determined whether the effect of dutasteride for benign prostatic hyperplasia is influenced by baseline prostate volume using data from 3 phase III clinical trials.

Materials And Methods: Patients randomized to dutasteride or placebo in the double-blind portion of the phase III studies were eligible to receive 0.5 mg dutasteride daily in a 2-year open label extension in dutasteride/dutasteride and placebo/dutasteride groups. Patients were prospectively stratified according to baseline prostate volume 30 to less than 40 and 40 cc or greater.

Results: In patients treated with dutasteride throughout the study (dutasteride/dutasteride group) the mean reduction in prostate volume from baseline to month 48 was 30.3% in those with a baseline prostate volume of 30 to less than 40 cc and 26.2% in those with a prostate volume of 40 cc or greater. Mean improvements in peak urinary flow from baseline to month 48 were 2.7 ml per second regardless of baseline prostate volume. Improvements in the American Urological Association symptom index score were 6.3 in men with a prostate volume of 30 to less than 40 cc and 6.5 in those with a prostate volume of 40 cc or greater. No significant relationships between treatment effect and baseline prostate volume were observed for these parameters. In dutasteride/dutasteride treated patients the risk of acute urinary retention was decreased by 60% in those with a prostate volume of 30 to less than 40 cc and 55% in those with a prostate volume of 40 cc or greater vs values in placebo/dutasteride treated patients (p = 0.036 and <0.001, respectively). The corresponding values for benign prostatic hyperplasia related surgery were 27% and 48% (p = 0.35 and <0.001, respectively).

Conclusions: This analysis demonstrates that dutasteride significantly improves objective (prostate volume and peak urinary flow) and subjective (symptom scores) measures even in patients with only a slightly enlarged prostate (30 to less than 40 cc). The risks of acute urinary retention and benign prostatic hyperplasia related surgery were decreased regardless of baseline prostate volume.