A Drug Interaction Study With Fluticasone Furoate/GW642444 Inhalation Powder and Ketoconazole

This will be a single centre, randomized, double-blind (with respect to ketoconazole), two-way cross-over study in healthy male and female subjects. Subjects will attend for a screening visit within 28 days prior to the first treatment period. There will be two study periods, each consisting of 14 days. Ketoconazole or matching placebo will be administered for 11 days with fluticasone furoate/GW642444M inhalation powder co-administered on Days 5-11. During each period subjects will be required to report to the unit on Day -1 and will remain there until 1 hour post-dosing with ketoconazole or placebo on Day 1. Subjects will return to the unit on the mornings of Day 2 to Day 4 for dosing with ketoconazole or placebo. Subjects will then return on the evening of Day 4 and leave the unit on the morning of Day 6 (2 nights). Subjects will return to the unit on the mornings of Day 7 to Day 10 for dosing and pre-fluticasone furoate/GW642444M dose safety assessments. Subjects will return on the evening of Day 10 and leave the unit on the morning of Day 12 (2 nights). Subjects will make two outpatient visits, one in the evening on Day 12 and one in the morning on Day 13, to complete a few study related procedures. The two treatment periods will be separated by a washout of at least 7 days and no more than 14 days. Pharmacodynamic profiles for potassium, heart rate, QTc, blood pressure and serum cortisol will be taken on Day 11 with fluticasone furoate and GW642444 pharmacokinetic profiles on Days 5 and 11. Safety assessments will include vital signs, ECGs, adverse event monitoring and laboratory safety tests, plus blood glucose and blood potassium profiles on Day 5.