Persistence of effectiveness of bronchial thermoplasty in patients with severe asthma

Background: Bronchial thermoplasty (BT) has been demonstrated to be safe and effective in the treatment of severe persistent asthma out to at least I year. Preclinical studies have demonstrated that the reduction in airway smooth muscle after bronchial thermoplasty persists out to at least 3 years. Objectives: To examine the persistence of effectiveness of BT 2 years posttreatment in subjects with severe asthma. Methods: Subjects participating in the long-term safety follow-up phase of the Asthma Intervention Research 2 (AIR2) Trial were evaluated by comparing the proportion of subjects who experienced exacerbations, adverse events, or healthcare utilization during the first year (year 1) after BT treatment with the proportion of subjects who experienced the same during the subsequent 12 months (year 2). Results: Severe exacerbations, respiratory adverse events, emergency department visits for respiratory symptoms, and hospitalizations for respiratory symptoms (proportion of subjects experiencing and rates of events), and stability of pre- and post-bronchodilator forced expiratory volume in 1 second (FEV1), were comparable between years I and 2. The proportion of subjects experiencing severe exacerbations in year 2 after BT was 23.0%, compared with 30.9% in year I. Conclusions: The reduction in the proportion of subjects experiencing severe exacerbations after BT is maintained for at least 2 years. Bronchial thermoplasty provides beneficial long-term effects on asthma outcomes in patients with severe asthma.