Mirabegron: A Review in Overactive Bladder Syndrome

The first-in-class β₃-adrenoceptor agonist mirabegron is indicated in the EU (Betmiga™), Japan (Betanis™) and several other countries for the management of overactive bladder (OAB) syndrome. Evidence for its use in this setting includes several large phase 3 trials. Compared with placebo, oral mirabegron for 12 weeks reduced the frequency of micturition and generally also that of incontinence, with other benefits including reduced urgency, increased void volume and improved health related quality-of-life (HR-QOL). Mirabegron comparisons versus tolterodine are descriptive; however, in a 12-week powered comparison versus solifenacin in patients dissatisfied with antimuscarinic efficacy, mirabegron did not demonstrate noninferiority in reducing micturition frequency or significantly differ in terms of improving other urinary symptoms. Urinary and HR-QOL benefits of mirabegron were sustained over up to 52 weeks of treatment and the drug was generally well tolerated, with a numerically lower incidence of dry mouth than antimuscarinics. Real-world data support the trial findings and indicate possible persistence and adherence benefits for mirabegron over antimuscarinics. Mirabegron use is not generally restricted by patient age, sex or antimuscarinic treatment status, although data in men (from a phase 4 study and phase 3 trial subanalyses) are variable; additional studies in older and male OAB patients are awaited with interest. Although further longer-term efficacy and tolerability data would be beneficial, current clinical evidence indicates that mirabegron provides an alternative to antimuscarinics for the management of OAB in adults, including those for whom antimuscarinics have proven unsuitable.