A 3 Way Cross-over Study Evaluating the Effects of ADOAIR Twice Daily Plus Tiotropium Bromide Once Daily Compared With the Individual Treatments of Japanese Subjects

The purpose of this study is to evaluate the effects on lung function of a combination of ADOAIR 50/250mcg twice daily plus tiotropium bromide 18mcg once daily compared with the individual treatments (tiotropium bromide 18mcg once daily alone and ADOAIR 50/250mcg twice daily alone) in Japanese subjects with COPD. The study will utilize a three-way cross-over design with a 2-week wash-out period between each 4-week consecutive treatment period. The aim is to support the rationale for "triple combination" therapy by demonstrating that treatment with both ADOAIR and tiotropium can potentially produce improved, clinically relevant effects compared with either treatment alone. This study will utilize a range of lung function measures in order to fully assess the benefits of triple therapy. The primary endpoint will be based on airways conductance measured using plethysmography (sGaw measured over 4hours post dose (AUC 0-4hr) on Day 28). Secondary endpoints will include lung function measures based on plethysmography and spirometry. The lung function measures will be supported by measurement of the use of relief salbutamol .