How Different Beta-2 Receptor Genotypes Affect an Asthmatic's Response to Regular Salmeterol Treatment

Inclusion Criteria: * Both male and female * 18 to 50 years of age * Resting FEV1 ≥ 65% of predicted normal * Exercise-induced bronchoconstriction defined as a decrease in FEV1 of ≥ 20% following a standardized exercise challenge when compared to pre-exercise baseline FEV1 value measured 5 minutes before exercise * Must be Arg/Arg or Gly/Gly genotype Exclusion Criteria: * Long-acting beta agonist use within 12 weeks of the first exercise challenge * Smoking within past 12 months * Greater than 10-pack years smoking history * Unresolved signs and/or symptoms of an upper respiratory tract infection within 4 weeks of first exercise challenge * Asthma exacerbation within 4 weeks of first exercise challenge requiring change in type, dose or frequency of medications and/or an unscheduled visit to an health care provider, including emergency room or hospital * Subject has exercised or performed strenuous activity within 72 hours of the first exercise challenge * Subject has been exposed to cold air sufficient to provoke symptoms of bronchospasm within 2 hours of exercise challenge * In addition to asthma, the subject has an active, acute or chronic pulmonary disorder documented by history, physical examination, or chest x-ray * Subject has evidence of ischemic, valvular, hypertrophic, familial or other forms of heart disease that would put the subject at risk during exercise testing or that would interfere with the ability to achieve protocol-specified heart rates during exercise testing * Subject has used systemic corticosteroids within 1 month of first exercise challenge