Mirabegron versus vibegron in previously untreated female patients with overactive bladder: A randomized, single-clinic, open-label trial

Objectives

This study aimed to assess the efficacy and safety of mirabegron compared with vibegron (both 50 mg once daily) in Japanese female patients with symptoms of overactive bladder (OAB).

Methods

This prospective, 12-week, two-arm, parallel-group, open-label randomized trial (UMIN000038288) was conducted at a single clinic from December 2019 to September 2022. The primary efficacy outcome measure was the change in mean total overactive bladder symptom scores (OABSSs) from baseline to end of treatment (EOT) (Week 12). The secondary efficacy outcome measures were changes in mean International Prostate Symptom Score from baseline to EOT, the ratio of patients who achieved a minimal clinically important change (MCIC) of total OABSS, and individual domains of the King's Health Questionnaire. Safety assessments, such as adverse events (AEs), postvoid residual volume, and patient-reported incidences, were recorded at every visit.

Results

There was no statistically significant adjusted mean difference between mirabegron and vibegron in terms of the primary outcome of the mean change from baseline to EOT in the total OABSS. The difference in the percentage of patients in the mirabegron and vibegron groups achieving an MCIC on the total OABSS was not statistically significant but appeared to be clinically important. The incidence of treatment-related AEs was significantly higher for the vibegron group (38.5%) than the mirabegron group (19.1%) (p = .047).

Conclusions

These results showed that both drugs were effective in female OAB patients, with no significant differences in terms of efficacy. However, the safety of vibegron requires further investigation.