A Randomized, Double-blind, Placebo-controlled Cross-over Study to Determine the Bronchodilator Effect of a Single Dose of Fluticasone Furoate (FF)/ Vilanterol (VI) 100/25 mcg Combination Administered in the Morning in Adult Patients With Asthma

The study will be a randomized, double-blind, placebo controlled cross-over study in 32 adult subjects with moderately severe asthma. In this study the bronchodilator effect of a single morning dosing of FF/VI combination 100/25 mcg will be determined by spirometry. After the screening the subject will be randomized and will be assigned to one of two treatment sequences (AB or BA, where A is placebo and B is FF/VI 100/25 mcg). Between the two treatment periods there will be a washout period of 7-14 days. A serial forced expiratory volume in one second (FEV1) measurements will be taken at 15, 30 minutes, 1, 2, 4, 12, 24, 36, 48, 60 and 72 hours post dose. Safety assessments will include vital signs, electrocardiograms (ECGs), adverse event (AE) monitoring and laboratory safety tests however, these will not constitute study endpoints. The results of the study will provide supporting information to prescribers on the bronchodilator effect of FF/VI over 72 hours.