Asthma Clinical Research Network (ACRN) Trial - Long-Acting Beta Agonist Response by Genotype (LARGE)

BACKGROUND: The purpose of this study is to compare the effects of a long-acting beta agonist in patients with asthma receiving inhaled corticosteroids who express two distinct polymorphisms of the beta-2 adrenergic receptor. DESIGN NARRATIVE: Participants were homozygous for arginine or glycine at the 16th amino-acid position of the β-2 adrenergic receptor (B16 Arg/Arg or B16 Gly/Gly). Individuals were matched against their opposite genotype by forced expiratory volume in one second (FEV1) and race. Matched participants entered an 8-week run-in period. This is a 62-week crossover design where subjects receive the following therapies: * Beclomethasone HFA (240 µg twice a day (BID)) + as-needed (PRN) albuterol: 8-week run-in * Beclomethasone HFA (240 µg BID) + salmeterol (50 µg BID) + PRN ipratropium bromide + PRN albuterol: 18-week treatment period * Beclomethasone HFA (240 µg BID) + PRN albuterol: 8-week run-out * Beclomethasone HFA (240 µg BID) + placebo salmeterol + PRN ipratropium bromide + PRN albuterol: 18-week treatment period * Beclomethasone HFA (240 µg BID) + PRN albuterol: 10-week run-out The order of treatments received during the two treatment periods is randomized.