A Study to Compare the Efficacy and Safety of Umeclidinium/Vilanterol and Fluticasone Propionate/Salmeterol in Subjects With Chronic Obstructive Pulmonary Disease (COPD)

This is a multicenter, randomized, double-blind, double-dummy, parallel group study. The purpose of this study is to compare the efficacy and safety of umeclidinium/vilanterol (UMEC/VI) and fluticasone propionate/salmeterol (FSC) in subjects with COPD. Subjects who meet the eligibility criteria at Screening will complete a 7 to 14 day Run-in period. At the end of the run-in period, approximately 710 eligible subjects will be equally randomized (to complete at least 568 evaluable subjects) to one of the 2 treatment groups for 12 weeks: 1. UMEC/VI 62.5/25 micrograms (mcg) administered as one inhalation once-daily in the morning via the Novel dry powder inhaler (NDPI) + placebo administered as one inhalation each morning and evening via single multidose powdered inhaler (ACCUHALER/DISKUS) or 2. FSC 250/50 mcg administered as one inhalation each morning and evening via ACCUHALER/DISKUS + placebo administered once-daily in the morning via NDPI. A safety Follow-up assessment will be conducted approximately 7 days after the end of the study treatment (Early Withdrawal, if applicable). The total duration of subject participation will be approximately 15 weeks.