Antimuscarinic agents remain the mainstay of medical management of bladder overactivity. Limited somewhat by their tolerability, the new agent mirabegron, a β3-adrenoreceptor agonist, has been approved as an alternative. There is little known however about the possible synergistic effects of the two drug classes. This multicentre, randomised, double-blind trial aimed to evaluate the efficacy of solifenacin and mirabegron in varying dose combinations, compared to either drug as a monotherapy or a placebo. In total 1306 patients were randomised to one of 12 treatment groups. The primary study endpoint was mean volume voided per micturition (MMV). Secondary endpoints included number of voids and number of incontinence episodes per 24-hour period. Various safety parameters were evaluated, including post-void residual volumes. Compared with solifenacin 5mg monotherapy, combinations of mirebegron with solifenacin 5mg or 10mg significantly improved MVV. Various combination groups also significantly reduced void frequency and urgency episodes. There were however, except for a slightly increased rate of constipation, little changes in the rate of adverse effects, and of note no important increase in the post-void residuals in the combination groups. For those patients for whom bladder overactivity is an ongoing concern, yet who are not suitable for or keen on surgical intervention, this study has shown combination therapy may safely be considered to improve their symptoms.
Solifenacin and mirabegron are safe and effective in combination
Reviewed by Sophia Cashman
Combination treatment with mirabegron and solifenacin in patients with overactive bladder: efficacy and safety results from a randomised, double-blind, dose-ranging, phase 2 study (Symphony).
