Long-term sustained improvement in symptoms of benign prostatic hyperplasia with the dual 5α-reductase inhibitor dutasteride: Results of 4-year studies

OBJECTIVE: To report additional analyses of efficacy over the initial 2 years and during a 2-year open-label extension of the three pivotal phase 3 studies in which dutasteride, a dual inhibitor of type 1 and 2 5α-reductase, was shown to be effective and well tolerated. PATIENTS AND METHODS: All patients in the placebo and active groups were eligible for entry into the 2-year open-label extension, with all receiving dutasteride 0.5 mg daily. Mean changes from baseline were calculated for the American Urologic Association Symptom Index (AUA-SI) score at each scheduled time in the double-blind and open-label phase. The additional analyses included a breakdown of the AUA-SI score, including stratifying patients by symptom severity, assessment by baseline age and prostate volume, and the evaluation of symptoms responders. RESULTS: There was a clinically meaningful improvement in AUA-SI in patients on dutasteride in the double-blind phase, but not in those on placebo. At 48 months, patients on dutasteride in both study phases had greater improvements in AUA-SI score and individual question scores than those on dutasteride in the open-label phase only. The proportion of patients with severe symptoms declined in both study groups, although these changes were more profound in those receiving dutasteride for the 4-year duration of the study. CONCLUSION: In men with symptomatic benign prostatic hyperplasia, long-term (4-year) treatment with the dual isozyme 5α-reductase inhibitor dutasteride resulted in sustained and continued improvements in symptoms and flow rate. For 4 vs 2 years, longer dutasteride therapy resulted in greater symptom improvement.