A Study Comparing the Closed Triple Therapy, Open Triple Therapy and a Dual Therapy for Effect on Lung Function in Subjects With Chronic Obstructive Pulmonary Disease (COPD)

Dry white powder delivered via ELLIPTA inhaler(2 strips with 30 blisters each, first containing fluticasone furoate 100 mcg per blister and second containing Umeclidinium 62.5 mcg and Vilanterol 25 mcg per blister), administered as one inhalation of FF/UMEC/VI (100/62.5/25 mcg) once-daily in the morning

Dry white powder delivered via ELLIPTA inhaler (2 strips with 30 blisters each, first containing fluticasone furoate 100 mcg per blister and second containing Vilanterol 25 mcg per blister), administered as one inhalation of FF/VI (100/25 mcg) once-daily in the morning

Dry white powder delivered via ELLIPTA inhaler (1 strip with 30 blisters containing Umeclidinium 62.5 mcg, administered as one inhalation once-daily in the morning

Placebo will be administered via ELLIPTA inhaler. Dry white powder administered as one inhalation each morning (1 strip with 30 blisters containing placebo)

Albuterol/salbutamol will be administered via metered-dose inhaler (MDI) with a spacer as needed throughout the study as a rescue medication