Published Online: September 3, 2013
Bronchial Thermoplasty (BT) is a non-pharmacologic treatment for asthma that has been shown to result in significant improvements in a number of asthma control measures in three randomized clinical trials in patients with moderate-to-severe, persistent asthma. The Asthma Intervention Research 2 (AIR2) Trial, a double-blind, sham-controlled, randomized clinical trial of BT in patients with severe asthma, showed a 32% reduction in severe exacerbations, an 84% reduction in emergency room (ER) visits due to respiratory symptoms, and a 66% reduction in time lost from work/school/other daily activities due to asthma symptoms compared to a sham-treated group in the first year following the BT treatment period (day of first BT procedure until 6 weeks after the last bronchoscopy, approximately 12 weeks).
Recently in The Journal of Allergy & Clinical Immunology (JACI), Wechsler at el describe their findings on the long-term safety and durability of BT out to 5 years post-treatment in BT-treated patients from the AIR2 Trial. They compared severe exacerbations, adverse events, healthcare utilization and spirometry data in each of years 2, 3, 4, and 5 to the first year after the BT procedure to see whether the benefit seen against the Sham group in the first year after BT was maintained. They also looked at sequential high resolution computed tomography (HRCT) scans for a group of patients in years 1, 3 and 5 to evaluate any structural changes in the airways. One hundred and sixty two of the original 190 subjects in the BT group completed evaluations at Year 5.
The authors found that the reduction in the percentage of BT-treated patients experiencing severe exacerbations (compared to sham-treated patients) seen at 1 year was maintained out to 5 years with a 48% average decrease over 5 years in severe exacerbation event rates (events per patient per year) in BT-treated patients compared with the 12 months prior to BT treatment. The decrease in severe exacerbations in the BT-treated patients studied over 5 years included a substantial reduction in the use of systemic corticosteroids associated with those exacerbations. Similarly, the reduction in the percentage of BT-treated patients having emergency room visits for respiratory symptoms (compared to sham -treated patients) seen at 1 year was maintained out to 5 years with an 88% average decrease over 5 years in the rate of ER visits for respiratory symptoms (events per patient per year). There was no increase over 5 years in hospitalizations, respiratory adverse events, or asthma symptoms, There was no difference in the percent of patients experiencing severe exacerbations, ER visits, and asthma symptoms over 5 years based on the allergy status (patient reported) of the patient. One in 4 BT-treated patients (28%) saw a 50% or greater reduction from baseline average ICS dose at 5 years, with an average reduction of 18% from baseline for BT-treated patients at 5 year. The authors demonstrated long term safety of the BT procedure based on the absence of clinically meaningful changes in lung function (FEV1) at 5 years, no increase in the baseline rate of hospitalizations at 5 years and no structural changes in the airways (based on HRCT review) at 5 years that were clinically significant and no increase in the incidence of respiratory events seen from 6 weeks post-BT treatment to 5 years.
The authors concluded that a single series of BT treatments safely provides asthma control (based on maintained reduction in severe exacerbations and ER visits for respiratory symptoms) out to at least 5 years. The authors’ findings support BT as an important option for patients with severe asthma who remain symptomatic despite taking current standard of care medications.
The Journal of Allergy and Clinical Immunology (JACI) is the official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.