This study will compare two treatment strategies (doubling the dose of inhaled steroids or adding a long acting beta2 agonist to the inhaled steroid at the same dose) in children not controlled by inhaled steroid alone at medium dose. The fixed combination SERETIDE 100/50 one inhalation twice daily will be compared to FLIXOTIDE 100 two inhalations twice daily.

A multicentre, randomised, double-blind, double dummy, parallel group study to compare the salmeterol/fluticasone propionate combination (SERETIDE™) at a dose of 50/100mcg twice daily and fluticasone propionate (FLIXOTIDE™) at a dose of 200mcg twice daily, both delivered via a dry powder inhaler (DISKUS™) for 12 weeks in asthma in children aged 4-11 years not controlled by inhaled corticosteroids alone at medium dose

• Drug: Fluticasone propionate
• Drug: Fluticasone propionate/salmeterol

Inclusion criteria:

• A documented clinical history of asthma for a period of at least 6 months.
• A documented history (within 12 months of Visit 1) of airway reversibility of = 15% based either on Forced expiratory volume (FEV1) or PEF measured pre and post inhalation of 200 mcg salbutamol. (If no documented history of reversibility exists, patients must demonstrate a =15% reversibility at Visit 1).
• Receiving an inhaled corticosteroid at a medium dose (beclomethasone dipropionate HydroFluoroAlkane (HFA) non fine particle = 400-500 mcg/day or beclomethasone HFA fine particle = 200mcg/day, or budesonide =400 mcg/day or fluticasone = 200 mcg/day (or fluticasone 250mcg/day if subject is taking a 125mcg MDI rather than the 100mcg Diskus), for at least 3 months prior to Visit 1 and at a stable dose for at least 4 weeks prior to Visit 1.
• Able to use the Mini-Wright peak flow meter and subject or parent/guardian had to be able to record the subject's maximum PEF correctly.
• Able to perform FEV1 correctly.
• Subject's guardian/parent able to complete an eDRC on behalf of the subject. The eDRC should be completed by the guardian/parent.
• Able to use a DISKUS™ correctly.
• At least one parent(s)/guardian(s) has to give written informed consent to participate in the study.

At the end of the run-in period (Visit 2), subjects must still meet the criteria for entry into the run-in period and also have:

• not achieved the criteria for the 'Well-controlled' asthma during two or more of the 4 weeks prior to Visit 2.

Exclusion criteria:

• Female subjects who have reached menarche.
• Received any investigational study medication in the 4 weeks prior to Visit 1.
• Experienced a respiratory tract infection in the 4 weeks prior to Visit 1.
• Experienced an acute asthma exacerbation requiring emergency room treatment within 4 weeks or hospitalisation within 12 weeks of Visit 1.
• Any use of oral/parenteral or depot corticosteroid within 12 weeks of Visit 1.
• Any use of long-acting inhaled beta2-agonists or oral beta2-agonists within 4 weeks of Visit 1.
• Any use of leukotriene antagonists or theophyllines within 4 weeks of Visit 1.
• Any known clinical or laboratory evidence of a serious uncontrolled disease (including serious psychological disorders) which is, in the opinion of the investigator, likely to interfere with the study.
• Subjects with a known or suspected hypersensitivity to inhaled corticosteroids, beta2-agonists, or any components of the formulations (e.g. lactose)
• A relative of any of the site staff, including the investigator or study co-coordinator.
• Has previously been entered into this study.

Subjects will be excluded from participating in the treatment period of the study if the following occurred during the run-in period:

• Pre-bronchodilator FEV1 <60% (assuming that measurement was correctly performed).
• Any change in asthma medication (excluding use of prophylactic study specific salbutamol for prevention of asthma symptoms due to exercise).
• Respiratory tract infection or asthma exacerbation.
• Use of oral, parenteral or depot corticosteroids.
• Emergency visit due to asthma.
• Non-compliance with the completion of the eDRC (i.e. during the 4 week period between visits, non compliance is defined as less than 5 days of completed data within any one week for four weeks - subjects must complete at least 5 days a week for the entire run-in period).