Inhaled Fluticasone Furoate/Vilanterol Safety and Tolerability, PK and PD Study

This study will investigate the safety and tolerability, pharmacokinetics, and pharmacodynamics of fluticasone furoate/vilanterol (FF/VI) 100/25mcg administered using the novel dry powder inhaler in children aged 5 to 11 years with persistent asthma. Fluticasone furoate (FF, GW685698) is a novel once daily inhaled corticosteroid (ICS) and vilanterol (VI, GW642444) is an inhaled once daily long-acting beta2 agonist (LABA). FF/VI is a novel ICS/LABA combination with once-daily dosing being developed for the treatment of asthma in adults, adolescents, and children of 5 years and above. This study will be a randomized, double-blind, repeat dose, two period crossover study, with FF as the control. During each of two treatment periods subjects will receive either FF/VI 100/25 micrograms (mcg) or FF 100 mcg daily on 14 consecutive mornings via the novel dry powder inhaler. Approximately 26 subjects will be recruited into this study, with a target of 20 completed subjects. Safety, tolerability, pharmacokinetics and glucose , potassium and cortisol levels will be investigated.