Pharmacogenetics of b2-Agonists in Asthma.

Patients are being asked to take part in this research study because they have asthma. This clinical research study is being done to see if an asthmatic's gene make-up (DNA is made up of genes) affects the way they respond to a particular asthma medication called salmeterol. Certain genes make people tall or short. Certain genes give people brown or black hair. Similarly, certain genes may be associated with the way patients respond to asthma medications.

Salmeterol xinafoate (a long acting bronchodilator) and fluticasone propionate (an inhaled corticosteroid) are the medicines contained in Advair Diskus. During this study, patients with asthma will receive fluticasone inhaler (called Flovent) and Advair Diskus. The investigators want to find out if patients with asthma with certain genes respond in different ways to the salmeterol in Advair Diskus. The investigators also want to find out if patients with asthma with certain genes who are treated with salmeterol for two weeks have their airways open up less than usual when they use albuterol.

Inclusion criteria

• Diplotype: Whites with specific diplotype and African Americans with specific diplotypes.
• Gender: Male or female. Women are eligible if they are not pregnant or lactating. Females subjects of childbearing potential will undergo a urine pregnancy test prior to each methacholine challenge test.
• Age: 10 years and older.
• Asthma Diagnosis: Physician diagnosed asthma according to American Thoracic Society criteria for at least 3 months.
• Asthma Therapy: There is no requirement for previous asthma therapy to be included in this study.
• Asthma Severity: forced expiratory volume in the first second (FEV1) must be >= 60% of predicted normal values for age, height, and gender.
• methacholine challenge test provocative concentration (20% fall in FEV1) of <=12]mg/ml.

Exclusion criteria

• History of life-threatening asthma: Any episode of asthma requiring intubation associated with hypercapnia, respiratory arrest, or hypoxic seizures.
• Asthma instability: Hospitalization for asthma within 3 months of Visit 1.
• Concurrent respiratory disease: Any respiratory disease other than asthma.
• Sensitivities: Sensitivities to methacholine, Flovent® MDI, ipratropium bromide, albuterol, or Advair Diskus® that would put the safety of the subject at risk.
• Respiratory Tract Infection: Any sinus, middle ear, oropharyngeal, upper or lower respiratory tract infection that has not resolved at least 2 weeks immediately preceding Visit 1, or for which antibiotic therapy has not been completed at least 2 weeks prior to Visit 1.
• Expected exposure to pollen allergen to which the patient is sensitive (by medical history of symptoms) during the 29 day study period. These patients can be studied when pollen exposure to which they are sensitive will not occur.