Combination therapy with muscarinic receptor antagonists (such as solifenacin) and mirabegron, a β3-adrenoceptor agonist, has synergistic effects that enable the long-term management of overactive bladder (OAB) symptoms; however, the balance between efficacy and tolerability of this combination versus that of monotherapy with either agent has yet to be established, Now, patient-reported outcomes (PROs) from the SYNERGY study indicate that, according to those receiving treatment, mirabegron plus solifenacin is more effective and better tolerated than either agent alone.

Data on PROs relating to various aspects of treatment satisfaction were collected from 3,494 patients randomized as part of the SYNERGY study using a range of validated questionnaires, including the OAB-q symptom bother score, HRQOL total score, treatment satisfaction visual analogue scale (TS–VAS), and patient perception of bladder condition (PPBC). At the end of 12 weeks of treatment, patients receiving 5 mg solifenacin plus either 25 mg or 50 mg mirabegron had significant improvements in OAB-q symptom bother score, indicating a reduction in the severity of OAB symptoms compared with those in either monotherapy group, or in the placebo group. Similarly, patients in either combination therapy group reported significant improvements in HRQOL score, including in the concern, coping and sleep, but not social subscores, compared with those in the monotherapy group. The authors highlighted that the effects of solifenacin plus mirabegron on quality of life are approximately the sum of those observed in the respective monotherapy groups. Similar statistically significant improvements in treatment satisfaction (TS–VAS) and perception of bladder condition (PPBC) were also observed in patients receiving combination treatment, compared with those receiving monotherapy.

Interestingly, patients in groups that reported the highest levels of improvement using the various PRO measures were also the most likely to complete the questionnaires, with 82.8% and 84.3% of patients in the combination groups completing the questionnaires, compared with 65.3% in the placebo group.

...mirabegron and solifenacin provides additive improvements in quality of life...

In conclusion, analyses of PRO data demonstrate that the combination of mirabegron and solifenacin provides additive improvements in quality of life, compared with either treatment as monotherapy. However, as noted by the authors, the inclusion criteria for SYNERGY stipulate ≥3 episodes of incontinence per week prior to randomization. These criteria would exclude approximately two-thirds of patients with OAB, and raise an important question regarding the relevance of these findings to everyday clinical practice.

These observations suggest that a moderate (5 mg) dose of an antimuscarinic agent, plus mirabegron should be considered the standard-of-care approach to the management of patients with OAB.