Efficacy of the β3-adrenoceptor agonist mirabegron for the treatment of overactive bladder by severity of incontinence at baseline: a post hoc analysis of pooled data from three randomised phase 3 trials

The β3-adrenoceptor agonist mirabegron is approved for treatment of the symptoms of overactive bladder (OAB). Incontinence can be the most bothersome of OAB symptoms. Hence, we conducted a post hoc analysis of pooled data from three randomised, double-blind, placebo-controlled, 12-wk, phase 3 studies of mirabegron to evaluate the efficacy of mirabegron 50mg in incontinent OAB patients and in subgroups of patients stratified by severity of incontinence at baseline (an average of two or more [FAS-I ≥ 2 subgroup] or four or more [FAS-I ≥ 4 subgroup] incontinence episodes per 24h at baseline, where FAS-I is the full analysis set-incontinence population) and to determine correlations between measures of efficacy and disease severity. Mirabegron 50mg resulted in statistically significant improvements from baseline to final visit versus placebo in mean number of incontinence episodes, micturitions, and urgency episodes per 24h and mean volume voided per micturition in the pooled incontinent population and in the FAS-I ≥ 2 and FAS-I ≥ 4 subgroups. Treatment effect versus placebo for incontinence and urgency episodes increased with increasing severity of incontinence at baseline. Moderate correlations were seen between improvement in both frequency of incontinence episodes and micturitions and baseline incontinence and micturition frequency, respectively, with mirabegron 50mg and placebo.

Patient summary: Incontinence can be the most bothersome of OAB symptoms; mirabegron 50mg once daily is effective for treatment of OAB symptoms in incontinent patients, and its effect increases with increasing severity of incontinence.