Machida K, Kawayama T, Kinoshita M, et al. - In this multicenter, randomized, double-blind, placebo-controlled 3×3 crossover phase II trial, researchers investigated whether oral administration of imidafenacin (an antimuscarinic agent) in patients with chronic obstructive pulmonary disease (COPD) is safe and effective. Participants were 27 male COPD patients with % forced expiratory volume in 1 s (FEV₁) ≥ 30% and < 80% predicted. These patients were randomized to a single oral dose of imidafenacin 0.1 mg, imidafenacin 0.2 mg, or placebo. Significant improvement in maximum change in FEV₁ from baseline to 24 hrs post-administration was noted in those who received either dose of imidafenacin vs those treated with placebo. They also found the significantly improved area under the curve in FEV₁ during 24 hrs following administration of 0.2 mg, but not 0.1 mg dose, vs placebo, and the improvement was significantly depended on dose-dependent manners. Findings revealed excellent safety and tolerability of a single oral dose of imidafenacin 0.1 mg or imidafenacin 0.2 mg in patients with COPD. The likely contribution of a single oral dose of imidafenacin 0.1 mg or imidafenacin 0.2 mg to the improvement of pulmonary function in these patients was also suggested.