Results of a randomized, double-blind, placebo-controlled study of mirabegron in a Taiwanese population with overactive bladder and comparison with other clinical trials

ObjectiveMirabegron, a β3-adrenoceptor agonist, has been shown to be effective and safe in the treatment of overactive bladder (OAB). The aim of this study was to assess the efficacy and safety of mirabegron (50 mg) versus placebo in Taiwanese patients with OAB.Materials and patientsThis was a multicenter, randomized, double-blind, parallel-group, placebo- and active-controlled trial conducted at 12 sites in Taiwan. Patients were randomized in a 1:1:1 ratio to receive placebo, mirabegron (50 mg), or tolterodine extended release (4 mg) orally once daily for 12 weeks. The primary efficacy end point was the change in the mean number of micturitions per 24 hours from baseline to the final visit. Secondary end points were volume voided, and the number of urgency, urinary incontinence, urge incontinence, and nocturia episodes per 24 hours; in addition, the King's Health Questionnaire (KHQ) was administered to assess effects on quality of life.ResultsA total of 218 patients were included in the full analysis set (68 in the placebo group; 76 in the mirabegron group; and 74 in the tolterodine group). The adjusted mean difference between the mirabegron and placebo groups for the change in mean number of micturitions per 24 hours was −1.42 (p = 0.004). The adjusted mean difference between the mirabegron and placebo groups with regard to the change in volume voided per micturition was 16.7 mL (p = 0.013). However, the mirabegron group did not show statistically significant superiority to the placebo group in the other efficacy variables. There was also no statistically significant difference between mirabegron and placebo in any KHQ domain score. The incidence of treatment-emergent adverse events in the mirabegron group was low and similar to that in the placebo group.ConclusionMirabegron at a dose of 50 mg once daily for 12 weeks is superior to placebo in reducing the frequency of micturitions in Taiwanese patients with symptoms of OAB. No clinically relevant, serious adverse events were identified.