A Randomized, Active-controlled, Double-blind, Double-dummy, Parallel Group Design, Multi-center Trial to Compare the Efficacy and Safety of 2.5 µg and 5 µg Tiotropium Inhalation Solution Delivered by the Respimat Inhaler With Tiotropium Inhalation Capsules 18 µg Delivered by the HandiHaler (TIOSPIR)

Direct comparison studies of the tiotropium HandiHaler® 18 µg and Respimat® 5 µg formulations have been limited to 4-week crossover studies. Therefore, prospective data from a trial of adequate size and duration is required to establish that compared to tiotropium HandiHaler®, tiotropium Respimat® will have (a) similar effects on safety and (b) similar or superior effects on exacerbations.