Effect of Tiotropium Inhalation Capsules (Spiriva) on Exercise Tolerance in COPD Patients

This is an 25-week multicenter, single country, randomised, double-blind, placebo-controlled, parallel group study to compare the efficacy of tiotropium inhalation capsules (Spiriva, Bromuro de Tiotropio) in patients with COPD participating in a pulmonary rehabilitation program. Following an initial screening, patients will perform a six minute walk test (Visit 1) and enter a 4-week run-in period. Patients will subsequently be randomized to tiotropium or placebo inhalation capsules taken once daily in the morning for the next 25 weeks. After successfully completing 4 weeks of study drug self-administration, patients will enter a period of pulmonary rehabilitation. Pulmonary rehabilitation will include aerobic lower limb exercise 3 times weekly for 8 weeks. After the last pulmonary rehabilitation session, patients will continue on study medication for a 12 week follow-up period. Six minute walk tests will be repeated during the run-in period at Week 0 (Visit 2) and Week 4 (Visit 3), at the conclusion of the 8 weeks of pulmonary rehabilitation (Visit 6) and the 12 weeks of follow-up (Visit 9). Pulmonary function testing will be conducted prior to the start of therapy at Visit 1 and at Visits 2 (week 0 ), 3 (week 4 ), 6 (week 13 ) and 9 (week 25 ). Study Hypothesis: The null hypothesis is that there is no difference in the increase in six minute walk distance between tiotropium and placebo groups following 8 weeks pulmonary rehabilitation program. The alternative hypothesis is that tiotropium with pulmonary rehabilitation increases six minute walk distance more than placebo with pulmonary rehabilitation. However, the two-sided test of hypothesis will be performed at 0.05 level of significance. Comparison(s): The primary endpoint is the six minute walk distance at visit 6. This endpoint will be compared between tiotropium and placebo using an analysis of covariance model with treatment, center and baseline (six-minute walk distance measured at visit 2 prior to dosing) as a covariate. Fifty-four meters has been determined to be the difference in six minute walk distance between tiotropium (Spiriva, Bromuro de Tiotropio) and placebo at 5% level of significance with at least 80% power using a two-tailed t-test.. .