A Study to Evaluate the Effect of the Combination of Umeclidinium (UMEC) and Vilanterol (VI) on Exercise Endurance Time (EET) in Participants With Chronic Obstructive Pulmonary Disease (COPD)

The DPI will contain a total of 30 doses. Each DPI will be comprised of two double-foil, laminate blister strips. Each blister of one strip will consist of 62.5mcg of UMEC blended with lactose and magnesium stearate while each blister of other strip will consist of 25 mcg of VI blended with lactose and magnesium stearate. Each actuation of the DPI will deliver the contents of one blister from each strip simultaneously

The placebo DPI, identical in appearance to the inhaler containing active study medication, will have two blister strips, each containing 30 blisters of lactose and magnesium stearate.

Albuterol/salbutamol MDI (metered-dose inhaler) or nebules will be permitted throughout the study as rescue medication, for use as-needed. Albuterol/salbutamol will be sourced from local commercial stock or provided centrally from GlaxoSmithKline. Nebules will not be supplied.