Long-term efficacy and safety of bronchial thermoplasty (bt): 3 year follow-up results from a large scale prospective study.

Document Type

Conference Proceeding

Publication Date


Publication Title

Am J Respir Crit Care Med


Bronchial thermoplasty (BT) is a non-pharmacologic, device-based treatment for subjects ≥18 years with severe persistent asthma not well controlled with inhaled corticosteroids (ICS) and long-acting beta-agonists (LABA). The “Post-FDA Approval Clinical Trial Evaluating BT in Severe Persistent Asthma“ (PAS2 study) collects real-world data on subjects undergoing BT treatment with the Alair BT System. We report follow-up results for major endpoints to 3 years. Methods: The PAS2 study is a prospective, open-label, observational, multi-center trial at US and Canadian centers. Subjects 18-65 years taking ICS ≥1000μg/day (beclomethasone or equivalent) and LABA ≥80μg/day (salmeterol or equivalent) were enrolled. Additional inclusion criteria were: pre-bronchodilator FEV1 ≥60% predicted, non-smoker for ≥1 year (/years if former smoker), ≥2 days with asthma symptoms in the last 4 weeks, AQLQ ≤6.25, and in the 12 months prior to BT treatment have ≤2 hospitalizations, ≤3 lower respiratory tract infections, and ≤3 severe exacerbations. Subjects diagnosed with other severe respiratory diseases were excluded. Baseline demographics and characteristics and medical history were previously reported at ATS 2017. We examined healthcare utilization (severe exacerbations, hospitalization, and ER visits), spirometry (FEV1 and FVC), and medication usage through 3 years post-therapy. Safety data for the treatment and post-treatment periods was also collected. Results: Of the 279 subjects treated with BT, 226 returned for their 3-year follow-up. The reduction in healthcare utilization seen at 2-years post-BT continued to the 3-year follow-up. The % subjects with severe exacerbations at 12 months prior to BT and 1-3 years post-BT were 78%, 50%, 46%, and 46%, respectively. Similar patterns were seen for hospitalizations and ER visits for asthma. Mean ICS dose dropped from 2275μg/day at baseline to 2083μg/day, 1924μg/day, and 2025μg/day for years 1, 2, and 3, respectively. OCS usage was at 19.4% at baseline but was reduced to 11.1%, 11.4%, and 10.0% for years 1, 2, and 3, respectively. Omalizumab usage remained consistent from baseline to year 3 at 14-16%. FEV1 and FVC also remained stable after BT treatment. PAS2 data out to 3 years confirmed safety of the BT procedure. Conclusion: The data for the PAS2 study indicates that improvements in asthma control with respect to severe exacerbations, hospitalizations and ER visits seen at 2 years are durable out to 3 years, and reductions in ICS and OCS usage are also maintained. (Table presented)



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