We previously reported a relatively good long-term persistence rate with mirabegron in patients with overactive bladder (OAB) before vibegron was launched in Japan [1]. Some reports suggested that there is a difference in adherence and persistence between the two β3 agonists [2]. Thus, we examined drug utilization and persistence rate of mirabegron and vibegron for overactive bladder in a real-world clinical setting.

Patients who were prescribed mirabegron or vibegron as the first treatment for OAB between August 2022 and December 2023 were retrospectively reviewed. The analysis included gender, age, pre-existing medical conditions, concomitant medications, discontinuation of the drug and reasons for discontinuation, and duration of medication. Factors influencing persistence were examined using the COX proportional hazards model, and Kaplan-Meier curves (log-rank test) were used to compare groups.

Of the 179 patients who were prescribed mirabegron or vibegron as the first treatment, 128 patients were eligible, excluding 51 patients (28.5%) who were determined not to have OAB. Mirabegron and vibegron were prescribed to 94 (73.4%) and 34 (25.6%) patients, respectively. Mirabegron and vibegron were prescribed more frequently in men (59 patients; 63%) and women (21 patients; 62%), respectively. The median persistence rate for β3 agonists overall was 13 (95% CI: 6-19) months. The number of patients who discontinued medication and the duration of discontinuation were 55 (59%), 8.9 months and 14 (41%), 10.6 months for mirabegron and vibegron, respectively. The most common reason for discontinuation was inadequate efficacy (42% vs. 29%, p=0.36) for mirabegron and side effects (29% vs. 50%, p=0.14) for vibegron. The median persistence rate for mirabegron and vibegron were 9 (95% CI: 5-18) months and not reached (95% CI: 5-NA), respectively (p=0.122: Figure).

Compared to anticholinergics, mirabegron have fewer side effects and are frequently used. The frequent use of mirabegron is probably due to concerns about the risk of urinary retention and increased residual urine, especially in men. The availability of another β3 agonist (vibegron) allows sequential mirabegron-to-vibegron therapy, that may influence the persistence rate of these drugs. The lack of statistical differences may be due to the small sample size.

Mirabegron is often used in the first line, especially in men. The persistence rates are similar for both drugs, but mirabegron is often discontinued due to ineffectiveness and vibegron due to side effects.

Wada N, et al. Int J Urol. 25: 501, 2018
Chastek B, et al. Neurourol Urodyn. 43: 1504, 2024