Fluticasone Propionate/Salmeterol Combination 250/50 DISKUS in the Exercise Endurance Time in Patients With Chronic Obstructive Pulmonary Disease

The objective of this study is to demonstrate that, when added to tiotropium (TIO), fluticasone propionate/salmeterol combination (FSC) DISKUS 250/50 significantly increases exercise endurance time (EET) in the endurance shuttle walk test (ESWT), compared to TIO alone. Male and female subjects at least 40 years of age with a diagnosis of Chronic Obstructive Pulmonary Disease (COPD) are eligible. Subjects will be screened and consented at or during a 6-week (wk) period prior to visit (V)1. The 4-wk run-in period begins immediately after V1, when subjects receive open-label TIO plus as-needed relief inhaler (identical formulations called albuterol in the US and salbutamol in Canada). At V2, subjects will perform an incremental shuttle walk test (ISWT) to establish their maximal walk response. The first ESWT will occur at V3. Subjects must demonstrate an EET of ≤20 min that is reproducible (EET from V3 and V4 varying by ≤2 min). Eligible subjects are then randomized at V5 to either FSC 250/50mcg DISKUS twice daily plus open label TIO 18 mcg daily, or placebo DISKUS twice daily plus open label TIO 18 mcg daily for the 4-wk treatment period. The last study visit is V6. The primary efficacy measure is the difference between the EET at V6 (wk-8) vs. V4 (wk-3; the last ESWT done before randomized study drug is given). Secondary efficacy measures include V6 vs. V4 comparisons in exercise dyspnea scale (EDS), exercise inspiratory capacity (EIC) and cardio-respiratory measurements (CRM), and V6 vs. V5 comparisons in dyspnea related to activities of daily living (baseline dyspnea index and transition dyspnea index interviewer-administered \[BDI-TDI\]) and quality of life (Chronic Respiratory Disease Questionnaire Self-administered Standardized \[CRQ-SAS\]). The safety measure will be an assessment of adverse events. We will also attempt to validate prospectively the minimal clinically-important difference (MCID) for a change in the EET through correlation with dyspnea and quali