Mrybetriq (Mirabegron) and Solifenacin (Vesicare) work together for IC and OAB patients.

Objective: To report the efficacy, safety, and tolerability of combination therapy with solifenacin 5 mg and mirabegron 50 mg versus solifenacin 5 mg or 10 mg in patients with overactive bladder.

Design: Randomized, double-blind, parallel group, multicenter, phase 3B study.

Methods: Eligibility criteria included age >18 years with overactive bladder symptoms for >3 months and at least 2 incontinent episodes per 24 hours. There was a 2-week no treatment washout period. Patients then entered a single-blind 4-week treatment phase on 5 mg of solifenacin. Those who achieved 100% continence then exited the study. Patients who remained incontinent were randomized. One arm was solifenacin 5 mg and mirabegron 25 mg, which was then dose-escalated to mirabegron 50 mg after 4 weeks in those who were still incontinent. A second arm was solifenacin 5 mg/day, and a third arm was solifenacin 10 mg/day. The treatment phase was a total of 12 weeks, and this was then followed up by a single-blind placebo phase of 2 weeks’ duration before the end of the study.

Results/Conclusions: The change from baseline to the end of treatment in the mean number of incontinent episodes per 24 hours, or the primary end point of the study, was statistically significantly greater with combination therapy (-1.80) versus solifenacin 5 mg (-1.53). At the end of treatment, reductions in mean daily micturitions and 3-day incontinent episodes were also statistically significantly greater with the combination versus solifenacin 5 mg. Combination therapy was noninferior to solifenacin 10 mg for both key secondary end points and superior to solifenacin 10 mg for the reduction in micturition frequency. No patient had urinary retention requiring catheterization. The incidence of treatment-related adverse events was 33.1% in the solifenacin 5-mg group, 39.4% in the solifenacin 10-mg group, and 35.9% in the combination group. The most common side effects were dry mouth and constipation.

Reviewer’s Comments: Both combination and solifenacin treatments were generally well tolerated and in line with the safety profiles of both mirabegron and solifenacin. Add-on therapy with mirabegron 50 mg for a 12-week period provided greater improvement in overactive bladder symptoms in incontinent overactive bladder patients who had an insufficient response to solifenacin 5 mg.(Reviewer–Karl J. Kreder, MD, MBA).