Bronchial Thermoplasty for Severe Asthma: 5-Year Clinical Trial Outcomes

Constricted Bronchial Tube
Constricted Bronchial Tube
A clinical trial of bronchial thermoplasty for severe asthma assessed efficacy and safety outcomes up to 5 years post treatment.

Patients with severe asthma that had been poorly controlled with corticosteroids and beta-agonists experienced improved asthma control, fewer hospitalizations, fewer emergency department visits, and reduced corticosteroid use up to 5 years post treatment with bronchial thermoplasty (BT), according to clinical trial results recently published in Chest.

Approved by the FDA in 2010, bronchial thermoplasty is the only FDA-approved procedure for asthma treatment. The procedure, which uses radiofrequency energy to

heat airway walls, is indicated for adult patients with severe, persistent asthma that is not well controlled with inhaled corticosteroids (ICSs) and long-acting beta-agonists (LABAs).

As a follow up to FDA approval, researchers conducted a clinical trial to examine the efficacy of bronchial thermoplasty 5 years post treatment, the Post-FDA Approval Clinical Trial Evaluating BT in Severe Persistent Asthma (PAS2; Identifier: NCT01350336). The prospective, open-label, observational, multicenter study included 284 patients in the US and Canada from 27 centers, aged 18 to 65 years, treated with ICSs equal to or greater than 1000 µg/d (beclomethasone or equivalent) and LABAs equal to or greater than 80 µg/d (salmeterol or equivalent).

Of these patients, 279 underwent BT (mean 45.7±11.6 years of age; 64.5% female; mean BMI 32.2±7.5kg/m2; 84% White; asthma diagnosis averaged 25.2 years prior to BT). Among these patients, 227 received 5 years of follow up. Medications, hospital visits, and severe exacerbations were noted for the year before BT treatment as well during the 5 years subsequent to BT. Spirometry was also remeasured each year.

Among the 227 patients who were followed for 5 years post BT, severe exacerbations dropped from 77.8% in the year before BT treatment to 42.7% at 5 years after treatment; emergency department visits from 29.4% to 7.9%; hospitalizations from 16.1% to 4.8%. From baseline to 5 years after treatment, oral corticosteroid treatment for maintenance dropped from 19.4% to 9.7%.

Moreover, the researchers added that “Subgroup analyses based on baseline clinical and biomarker characteristics revealed a statistically significant clinical improvement among all subgroups, including those based on eosinophil and neutrophil counts.”

In discussing study limitations, the investigators noted that those patients who were not included in the 5-year follow-up tended to have more severe exacerbations (92.3% vs 74.4%), emergency department visits (51.9% vs 24.2%), and hospitalizations (30.8% vs 12.8%) the year before BT compared with the patients in the full 5-year follow-up cohort, suggesting patients with the most severe asthma may have been excluded from analysis.

Disclosure: This study was sponsored by industry (Boston Scientific Corp), with some study authors declaring affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.


Chupp G, Kline JN, Khatri SB, et al. Bronchial thermoplasty in patients with severe asthma at 5 years: The post-FDA approval clinical trial evaluating bronchial thermoplasty in severe persistent asthma study. Chest. 2022;161(3):614-628. doi:10.1016/j.chest.2021.10.044