The purpose of this study is to compare the efficacy and safety of GW685698X 100mcg once daily either in the morning or the evening and GW685698X 250mcg administered once daily in the evening via DISKHALER for 28 days in subjects with persistent bronchial asthma.

Inclusion Criteria:

• Outpatients aged between 16- 65 years.
• Male and female; female subjects must be non-child bearing potential or of childbearing potenetial with negative pregnancy test and willing to use acceptable contraceptive methods
• Documented clinical history of persistent asthma first diagnosed at least 6 months prior to Visit 1
• Currently receiving inhaled short-acting beta-2 agonists for symptom relief
• A lung function of between 50 to 90% predicted (PEF)
• Increase in PEF of at least15%, 20 minutes after inhalation of 400mcg salbutamol

Exclusion Criteria:

• History of respiratory tract infection and/or exacerbation of asthma within a period of 4 weeks prior to Visit 1
• History of life-threatening asthma, defined as an asthma episode that required intubation and/or was associated with hypercapnoea, respiratory arrest or hypoxia seizures.
• A history of two or more asthma exacerbations requiring treatment with oral corticosteroids or hospitalisation in the 6 months before Visit 1.
• Past or present disease that, as judged by the investigator, may affect the outcome of this study. These diseases include, but are not limited to, cardiovascular disease, malignancy, hepatic disease, renal disease, haematologic disease, neurological disease, endocrine disease or pulmonary disease (including, but not confined to, chronic bronchitis, emphysema, bronchiectasis with the need of treatment, cystic fibrosis and bronchopulmonary dysplasia).
• Known or suspected sensitivity to corticosteroids, VENTOLIN, or the constituents of ROTADISKS (e.g., lactose).
• Undergoing allergen desensitisation therapy.
• Neurological or psychiatric disease or history of drug or alcohol abuse that would interfere with the subject's proper completion of the protocol requirements.
• Is a current smoker or has a smoking history of 10 pack years or more (e.g., 20 cigarettes/day for 10 years). Note: Current smoker is defined as currently smoking or stopped smoking within 6 months of screening visit.

Patient-level data for this study will be made available through www.clinicalstudydatarequest.com following the timelines and process described on this site.