This was a multicenter, open-label study to evaluate the safety and efficacy of add-on therapy with antimuscarinics in patients with OAB treated with mirabegron.~The total duration of the study period was 54 weeks in total, comprising a 2-week screening period and a 52-week treatment period. Patients who met the eligibility criteria for provisional enrollment received orally the study drug for the screening period (mirabegron 50 mg) once daily after breakfast for 2 weeks. Patients who met the eligibility criteria after the screening period were randomized to solifenacin 5 mg, propiverine 20 mg, imidafenacin 0.2 mg or tolterodine 4 mg in a 1:1:1:1 ratio, and received orally mirabegron 50 mg and antimuscarinics for 52 weeks. At week 8 visit, the dose of all antimuscarinics except for tolterodine could be increased by 2-fold (solifenacin 10 mg, propiverine 40 mg or imidafenacin 0.4 mg) if a patient met the following criteria: (1) had no response to the study drugs; (2) was considered by the investigator to have no safety concerns; and (3) agreed to increase the dose. However, in the event of AEs after the dose was increased, it could be reduced to the level before the increase. A dose increase for a second time after dose reduction was not permitted.
The objective of the study was to evaluate the safety and efficacy of add-on therapy with anticholinergics in patients with OAB on mirabegron.