Mirabegron: β3-Adrenergic Receptor Agonist for the Treatment of Overactive Bladder

Abstract

OBJECTIVE To review the place in therapy of mirabegron, a new oral β3-adrenergic receptor agonist, for the treatment of overactive bladder (OAB). DATA SOURCES A literature search of MEDLINE and MEDLINE In-Process & Other Non-Indexed Citations Databases (1996-April 2013) was conducted using the key words mirabegron, receptor, adrenergic, beta-3; adrenergic beta-3 receptor; beta-3 receptor, and overactive bladder; urinary bladder; overactive. All published articles regarding mirabegron were included. References of selected articles, data from poster presentations, and abstract publications were additionally reviewed. STUDY SELECTION AND DATA EXTRACTION Available English-language data from reviews, abstracts, presentations, and clinical trials of mirabegron in humans were reviewed; relevant clinical data were selected and included. DATA SYNTHESIS Mirabegron is the newest option for treatment of OAB with symptoms of urge incontinence. As a β3-receptor agonist, it reduces bladder muscle contractions. In two 12-week, randomized, double-blind, placebo-controlled Phase 3 studies, mirabegron significantly reduced the number of incontinence episodes per 24 hours from baseline (−1.47, −1.63, and −1.13; p < 0.05; and −1.57, −1.46, and −1.17; p < 0.05; all values for mirabegron 50 mg, 100 mg, and placebo). Micturitions per 24 hours were also reduced from baseline (−1.66, −1.75, and −1.05; p < 0.05; and −1.93, −1.77, and −1.34; p < 0.05; all values for mirabegron 50 mg, 100 mg, and placebo). A 12-month trial found mirabegron to have a safety and efficacy profile similar to that of tolterodine. CONCLUSIONS Treatment of OAB initially includes lifestyle and nonpharmacologic intervention; for patients with persistent symptoms despite these treatments, drug therapy represents a next-step approach for symptom control. Mirabegron alleviates symptoms of OAB while having a mechanism of action that provides an alternative for patients who are intolerant of or who have contraindications to anticholinergic agents. The place in therapy of mirabegron relative to anticholinergics in the treatment of urge incontinence has not yet been established.