The study consisted of Run in Phase (5 to 7 days), Treatment Phase (made up of 3 treatment periods of 14 days each separated by 10 to 14 days Washout Period) and Follow-up Phase (7 to 9 days after completion of final visit or premature discontinuation). Eligible subjects will be randomized to a sequence of UMEC 62.5 mcg, VI 25 mcg, and UMEC/VI 62.5/25 mcg such that all subjects will receive each treatment.