Conditions: Asthma
Allocation: RANDOMIZED | Intervention model: CROSSOVER
Enrollment: 87
Healthy volunteers: no

Brief summary:
The purpose of this trial is to determine whether regularly scheduled use of an inhaled long-acting beta agonist (salmeterol) in the setting of concomitant use of inhaled corticosteroids (beclomethasone hydroflouroalkane (HFA) inhaler) will have a detrimental effect on asthma control in people who bear the B16-Arg/Arg genotype of the beta-2 adrenergic receptor gene, as compared to people with asthma of similar severity who bear the B16-Gly/Gly genotype.

Detailed description:
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.

Arms:
arm 1: B16 Arg/Arg genotype Sequence 1: inhaled salmeterol + inhaled beclomethasone hydroflouroalkane (HFA), followed by inhaled placebo salmeterol + inhaled beclomethasone HFA Sequence 2: inhaled placebo salmeterol + inhaled beclomethasone HFA, followed by inhaled salmeterol + inhaled beclomethasone HFA arm 2: B16 Gly/Gly genotype Sequence 1: inhaled salmeterol + inhaled beclomethasone HFA, followed by inhaled placebo salmeterol + inhaled beclomethasone HFA Sequence 2: inhaled placebo salmeterol + inhaled beclomethasone HFA, followed by inhaled salmeterol + inhaled beclomethasone HFA

Interventions: intervention 1: salmeterol intervention 2: beclomethasone HFA
Intervention descriptions: intervention 1: 50 micrograms (mcg) twice per day (BID) (Serevent 50 mcg diskus, GlaxoSmithKline (GSK), North Carolina) intervention 2: 240 mcg beclomethasone HFA (QVAR, Teva Pharmaceutical Industries)

Protocol document: