This study may last up to 36-38 weeks. Patients will visit the clinic 11 times. A blood sample will be taken at Visit 1 to look at subjects' genes. Breathing tests will be done during the study. Study medicines and procedures will be provided at no cost. Patients will be treated with VENTOLIN (8 wks), ATROVENT (8 wks), then ADVAIR or SEREVENT (16 wks). ADVAIR and SEREVENT are FDA approved for the treatment of asthma in patients 4 years of age and older.

A Randomized, Parallel Group, Double-Blind, Comparative Trial Assessing Lung Function and Other Measures of Asthma Control in Adults and Adolescents, at least 12 Years of Age, with Persistent Asthma, Who Have Either a B16-Arg/Arg, a B16-Gly/Gly or a B-16 Arg/Gly Genotype and are Treated With Fluticasone Propionate/Salmeterol DISKUS™ Combination Product 100/50mcg or Salmeterol DISKUS 50 mcg BID

Inclusion criteria:

• Diagnosis of persistent asthma for 3 months.
• Use of short-acting beta-agonist medication like VENTOLIN.

Exclusion criteria:

• Hospitalization for asthma 6 months before study.
• Other serious diseases like congestive heart failure, uncontrolled hypertension, TB.
• Current use of inhaled or oral corticosteroids.

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