QTc Study GSK573719+GW642444

This is a randomized, placebo controlled, four period incomplete block,crossover thorough QT study to estimate the effect of repeat dose GSK573719/GW642444M (Vilanterol) combination and GSK573719 monotherapy on the QTc interval in healthy male and female subjects compared with placebo. At least 100 subjects will receive, four of five possible, 10-day repeat dose treatments. Treatments are placebo with a moxifloxacin placebo on day 10, placebo with moxifloxacin (400mg) on day 10, GSK573719/Vilanterol combination (125/25μg) with moxifloxacin placebo on day 10, GSK573719/Vilanterol combinatio (500/100μg) with moxifloxacin placebo on day 10, or GSK573719 (500μg) with a moxifloxacin placebo on day 10. All treatments are double blind except for moxifloxacin (400mg) and moxifloxacin placebo controls, given as a single-blind single dose on Day 10 of the appropriate treatment period. Primary endpoints are individual time-matched changes from baseline QTcF for GSK573719/Vilanterol combination (125/25μg) and GSK573719 (500μg), 0-24 hours after dosing on Day 10. Secondary endpoints will include individual time-matched changes from baseline in QTcF for GSK573719/Vilanterol combination (500/100μg) and moxifloxacin (400mcg) 0-24 hours after dosing on Day 10. Also changes from baseline in QTci, QTcB, QT, QRS, RR, PR and ventricular rate at each time point after 10 days dosing of each GSK573719 and GSK573719/Vilanterol treatment and single dose moxifloxacin (400mg). Maximal change from baseline 0-24hours after dosing on day 10 will be derived for QTcF, QTci and QTcB for each treatment. Plasma concentrations on Day 10 (0-24 hours) and pharmacokinetic parameters of GSK573719 and Vilanterol will also be derived. Key assessments: 12- lead electrocardiogram (ECG), pharmacokinetics. Safety will be assessed by blood pressure, heart rate, clinical laboratory safety tests and collection of adverse events (AEs).