Background Bronchial thermoplasty is a device-based treatment for subjects ≥18 years with severe asthma poorly controlled with inhaled corticosteroids and long-acting beta-agonists. The Post-FDA Approval Clinical Trial Evaluating Bronchial Thermoplasty in Severe Persistent Asthma (PAS2) study collected data on severe asthmatics undergoing this procedure. Research Question What are the 5-year efficacy and safety results in severe asthmatics who have undergone bronchial thermoplasty? Study Design and Methods This was a prospective, open-label, observational, multi-center study conducted in the United States and Canada. Subjects aged 18-65, taking inhaled corticosteroids ≥1000μg/day (beclomethasone or equivalent) and long-acting β-agonists ≥80μg/day (salmeterol or equivalent) were included. Severe exacerbations, hospitalization, emergency department visits, and medication usage were evaluated for the 12 months prior to and at years 1-5 post-treatment. Spirometry was evaluated at baseline and at years 1-5 post-treatment. Results 284 subjects were enrolled at 27 centers; 227 subjects (80%) completed 5 years of follow-up. By year 5 post-treatment, the proportion of subjects with severe exacerbations, emergency department visits, and hospitalizations was 42.7%, 7.9%, and 4.8%, respectively, compared to 77.8%, 29.4%, and 16.1% in the 12 months prior to treatment. The proportion of subjects on maintenance oral corticosteroids decreased from 19.4% at baseline to 9.7% at 5 years. Analyses of subgroups based on baseline clinical and biomarker characteristics revealed a statistically significant clinical improvement among all subgroups. Interpretation Five years after treatment, subjects experienced decreases in severe exacerbations, hospitalizations, emergency department visits and corticosteroid exposure. All subgroups demonstrated clinically significant improvement, suggesting that bronchial thermoplasty improves asthma control in different asthma phenotypes.
