This study will last up to 62 weeks. You will visit the clinic up to 17 times. Certain clinic visits will include physical examination, medical history review and lung function tests. The purpose of this study is to see if one asthma drug (fluticasone propionate/salmeterol) is better in reducing the number of asthma exacerbations compared with another drug (fluticasone propionate alone)

Inclusion criteria:

• History of asthma for at least 6 months.
• Taking a low-dose of an inhaled corticosteroid for at least one month prior to the study (such as fluticasone propionate or budesonide).

Exclusion criteria:

• History of life-threatening asthma.
• Hospitalized for asthma within 3 months prior to the study.
• Current respiratory tract infection.
• Will not be able to attend clinic visits for the entire length of the study.
• Certain medical conditions that will make being in the study unsafe (such as congestive heart failure, uncontrolled hypertension, tuberculosis or certain drug allergies).

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