This two-part study was randomized, double blind, placebo controlled in patients with moderate-to-severe COPD: Part 1: single-dose escalation, GB 12.5, 25, 50, 100 or 200 μg versus placebo; Part 2: repeat-dose (7-day), four-period crossover, GB 12.5, 25 or 50 μg twice daily (BID) versus placebo, with an open-label extension in which all patients received tiotropium 18 μg once daily.