A randomised, double-blind, parallel design, multi-institutional, non-inferiority phase IV trial of imidafenacin versus fesoterodine for overactive bladder

Aims: Our objective was to compare the efficacy and safety of imidafenacin over fesoterodine in patients with overactive bladder (OAB). Methods: This study is a randomised, double-blind, parallel-group, fesoterodine-controlled study in patients with continuous OAB symptoms for ≥ 3 months, daily mean voiding frequency (DMVF) ≥ 8, and daily mean urgency or urgency incontinence frequency ≥ 2. A twice-daily 0.1 mg imidafenacin with placebo, or once-daily 4 mg fesoterodine with placebo were administered for 12 weeks. The primary efficacy end-point was the difference in DMVF at 12 weeks. The secondary efficacy end-points were differences in daily mean: (i) voiding frequency at 4 and 8 weeks; (ii) urgency frequency; (iii) urgency incontinence frequency; (iv) incontinence frequency; (v) nocturia frequency; and (vi) quality of life score. The variables for safety analysis were adverse events, vital signs, residual urine volume and clinical laboratory tests. An efficacy analysis was conducted in per-protocol patients and the safety analysis was conducted in all randomised patients. Results: The differences in DMVF at 12 weeks were -3.38 ± 3.63 and -2.45 ± 3.73 in the imidafenacin and fesoterodine groups, respectively, and the difference was not significant between the two groups. Imidafenacin was non-inferior to fesoterodine, and the lower limit of 95% two-sided confidence intervals was -0.53. The other six secondary end-points and variables for safety analysis showed no difference between the two groups. Conclusions: Imidafenacin was non-inferior to fesoterodine in terms of efficacy, and showed no significant difference in terms of safety.