What clinical trials have been conducted on combination therapy for the treatment of benign prostatic hyperplasia (BPH)?

Updated: Feb 19, 2021
  • Author: Levi A Deters, MD; Chief Editor: Edward David Kim, MD, FACS  more...
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The Medical Therapy of Prostatic Symptoms (MTOPS) trial demonstrated that combination therapy reduced the risk of progression and produced a greater improvement in IPSS than therapy with finasteride or doxazosin alone. The risks of acute urinary retention (AUR) and BPH-related surgery were reduced with combination therapy or finasteride in comparison with doxazosin monotherapy. [25]

The Symptom Management After Reducing Therapy (SMART-1) trial demonstrated that after 6 months of combination therapy, discontinuation of the alpha-1-blocker is possible in men with moderate LUTS. However, those with severe LUTS may require longer combination therapy. [25]

The Medical Therapy of Prostatic Symptoms (MTOPS) trial demonstrated that combination therapy with doxazosin and finasteride was well tolerated, and was superior to placebo and monotherapy with either agent. The primary endpoints of the study were reduction in AUA-SI score, AUR, recurrent infections, renal insufficiency, incontinence, changes in flow, and PSA level and a lower rate of invasive treatments. MTOPS was a multicenter, 4- to 6-year, double-blind, randomized, placebo-controlled trial of 3,047 men with symptomatic BPH. [26]

Four-year results in the Combination of Avodart and Tamsulosin (CombAT) study revealed that for men with prostate volumes of 30-58 mL, combination therapy with dutasteride (dual 5-alpha-reductase inhibitor) and tamsulosin (alpha-1-blocker) improved symptoms, urinary flow, and QOL better than monotherapy with either drug, although not in men who had a prostate volume of 58 mL or more. [27] The adverse-effect profile of combination therapy was similar to that of monotherapy, although drug-related adverse events were more common with combination therapy. [28]  

CombAT was a 4-year, multicenter, randomized, double-blind, parallel group study of 4,844 men aged 50 years or older with moderate-to-severe BPH symptoms (IPSS ≥12), prostate volume of 30 mL or greater, and a PSA level of 1.5-10 ng/mL. This study contributed to the standard of care shifting towards combined drug therapy in appropriately selected patients, while better defining the role of the alpha-blockers. [29]

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