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

Objective: To assess efficacy and safety of mirabegron 25 mg/day and 50 mg/day for overactive bladder in Chinese participants. Methods: Participants of >= 18 years with overactive bladder symptoms lasting for >= 12 weeks, a mean of >= 8 micturitions per 24 h, and a mean of at least one episode of Grade 3 or 4 urgency or urge incontinence per 24 h based on the 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/day to 50 mg/day was permitted at weeks 4 and 8 according to the investigators' discretion. The primary efficacy endpoint was the change from baseline to Week 12 in the mean number of micturitions per 24 h in those randomized to mirabegron 50 mg/day. Secondary efficacy endpoints were the change in mean number of micturitions at weeks 4 and 8 in the mirabegron 50 mg/day group and weeks 4, 8, and 12 in the mirabegron 25 mg/day group, change from baseline to weeks 4, 8, and 12 in Grade 3 or 4 urgency episodes on the 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/day and 25 mg/day groups. Results: Statistically significant reduction (p<0.001) from baseline to Week 12 was observed in mean micturitions per 24 h for participants randomized to mirabegron 50 mg/day: mean +/- standard error: 11.71 +/- 0.43 at baseline, 7.80 +/- 0.24 at Week 12; adjusted mean change: -3.73 (95% confidence interval -4.30 to -3.16). Both doses showed statistically significant improvement in secondary efficacy endpoints at weeks 4, 8, and 12 versus baseline. Safety was consistent with mirabegron's known safety profile. Conclusion: The results support a mirabegron dosage of 50 mg/day for the treatment of OAB in China. (c) 2025 Editorial Office of Asian Journal of Urology. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).