Study Investigating Repeat Doses Of A New Medication (GSK159797) In Asthmatic Patients

Inclusion criteria: * Subjects with documented history of persistent asthma using corticosteroids at a total daily dose of 200 to 200mcg of FP or equivalent corticosteroid * Female subjects only using acceptable birth control method * Non-smokers * FEV1 between 60 and 90% predicted * Increase in FEV1 12% or greater and 300mL and greater after salbutamol use Exclusion criteria: * Past or present disease conditions * Normal screening Holter ECG * Respiratory tract infection within 4 weeks of screening * History of life threatening asthma * Previous use of COA