Open-label, randomized, post-authorization study of mirabegron in Chinese participants with overactive bladder

Abstract

ObjectiveTo assess efficacy and safety of mirabegron 25 mg and 50 mg for overactive bladder in Chinese participants. MethodsParticipants ≥18 years with overactive bladder symptoms for ≥12 weeks, average ≥8 micturitions per 24 h, and ≥1 episode of Grade 3 or 4 urgency or urge incontinence per 24 h based on Patient Perception of Intensity of Urgency Scale over a 3-day micturition diary period were randomized 2:1 to open-label treatment with oral mirabegron 50 mg or 25 mg once daily for 12 weeks (15 sites in China, January 2021–March 2022). A dose escalation from 25 mg to 50 mg was permitted at weeks 4 and 8 according to investigator discretion. Primary efficacy endpoint: change from baseline to Week 12 in mean number of micturitions per 24 h in those randomized to mirabegron 50 mg. Secondary efficacy endpoints: change in mean number of micturitions at weeks 4 and 8 in the mirabegron 50 mg group and weeks 4, 8, and 12 in the mirabegron 25 mg group, change from baseline to weeks 4, 8, and 12 in Grade 3 or 4 urgency episodes on Patient Perception of Intensity of Urgency Scale, episodes of daytime incontinence, nighttime incontinence, and urgency incontinence, and Overactive Bladder Symptom Score for mirabegron 50 mg and 25 mg groups. ResultsStatistically significant reduction (p<0.001) from baseline to week 12 was observed in mean micturitions per 24 h: mirabegron 50 mg (mean and standard error: 11.71 and 0.43 at baseline, 7.80 and 0.24 at Week 12; adjusted mean change −3.73 [95% confidence interval −4.30 to −3.16]). Both doses showed statistically significant improvements in secondary efficacy endpoints at weeks 4, 8, and 12 versus baseline. Safety was consistent with mirabegron's known safety profile. ConclusionThe results support a recommended dosage of 50 mg in China.