A randomized, double-blind, placebo- and propiverine-controlled trial of the novel antimuscarinic agent imidafenacin in Japanese patients with overactive bladder

To compare the efficacy and tolerability of imidafenacin, a novel antimuscarinic agent, with propiverine and a placebo in Japanese patients with overactive bladder (OAB). Men and women having OAB symptoms were randomized to double-blind treatment with 0.1 mg of imidafenacin twice daily, 20 mg of propiverine once daily, or a placebo for 12 weeks, and assessed for efficacy and safety. Overall, 781 patients were randomized to imidafenacin (324), propiverine (310), or a placebo (147). After 12 weeks of treatment, a significantly larger reduction in the mean number of incontinence episodes was observed in the imidafenacin group than in the placebo group (P < 0.0001). The non-inferiority of imidafenacin compared with propiverine was confirmed for the reduction in using incontinence episodes (P = 0.0014, non-inferiority margin: 14.5%). Imidafenacin was well tolerated. The incidence of adverse events with imidafenacin was significantly lower than with propiverine (P = 0.0101). Dry mouth, the most common adverse event, was significantly more common in the propiverine group than in the imidafenacin group (P = 0.0302). There were no significant increases in either the imidafenacin or placebo group in the mean QTc interval, whereas there was a significant increase in the mean QTc interval in the propiverine group (P < 0.0001), but there were no clinical arrhythmia and clinical arrhythmic events in any of the treatment groups. The novel antimuscarinic agent imidafenacin at a dose of 0.1 mg twice daily was not inferior to propiverine for the reduction of incontinence episodes, and well tolerated for the treatment of OAB symptoms.