A 12-month, open label, randomised, effectiveness study to evaluate fluticasone furoate (FF, GW685698)/vilanterol (VI, GW642444) Inhalation Powder delivered once daily via a Novel Dry Powder Inhaler compared with usual maintenance therapy in subjects with

The objective of the study is to compare the effectiveness of fluticasone furoate(FF)/vilanterol (VI) Inhalation Powder (FF 100mcg/VI 25mcg or FF 200mcg/VI 25mcg) with usual asthma maintenance therapy over twelve months in a large UK primary care population of subjects with Asthma. FF/VI will be administered once-daily (QD) via the Novel Dry Powder Inhaler (NDPI).