Results of a randomized, double-blind, parallel-group, placebo- and active-controlled, multicenter study of mirabegron, a β3-adrenoceptor agonist, in patients with overactive bladder in Asia.

Aims: To assess the efficacy and safety of mirabegron 50 mg once daily compared with placebo and the active control, tolterodine extended-release (ER) 4 mg once daily, in patients with symptoms of overactive bladder (OAB) in Taiwan, Korea, China, and India.

Methods: A 12-week multinational, randomized, double-blind, parallel-group placebo- and active-controlled trial. The primary efficacy endpoint was change from baseline to final visit in mean number of micturitions/24 hr. Secondary endpoints were: mean number of urgency episodes, incontinence episodes and urge incontinence episodes/24 hr, mean number of nocturia episodes per night, mean volume voided per micturition, and quality-of-life (QoL) scores as assessed by the King's Health Questionnaire (KHQ).

Results: Of 1,126 patients who were randomized to receive double-blind study drug, 921 patients (300, 311, and 310 in the placebo, mirabegron 50 mg, and tolterodine ER 4 mg groups, respectively) completed the treatment period. Demographic characteristics were similar across treatment groups. A statistically significant improvement versus placebo in mean number of micturitions/24 hr was seen with mirabegron 50 mg at all timepoints (P < 0.05) as well as final visit (-0.57 with 95% confidence intervals [CIs] of [-1.04, -0.09], P = 0.019). There was no significant difference between treatment groups in improvement from baseline to final visit in any of the secondary outcome measures except volume voided per micturition. The overall incidence of drug-related adverse events was 17.2%, 15.8%, and 21.3%, in the placebo, mirabegron 50 mg, and tolterodine ER 4 mg groups, respectively.

Conclusions: Mirabegron 50 mg once daily for 12 weeks was superior to placebo in reducing the frequency of micturitions in patients with symptoms of OAB in Taiwan, Korea, China, and India.