Long-term (5 year) safety of bronchial thermoplasty: Asthma Intervention Research (AIR) trial

Abstract

BackgroundBronchial thermoplasty (BT) is a bronchoscopic procedure that improves asthma control by reducing excess airway smooth muscle. Treated patients have been followed out to 5 years to evaluate long-term safety of this procedure.MethodsPatients enrolled in the Asthma Intervention Research Trial were on inhaled corticosteroids ≥200 μg beclomethasone or equivalent + long-acting-beta2-agonists and demonstrated worsening of asthma on long-acting-β2-agonist withdrawal. Following initial evaluation at 1 year, subjects were invited to participate in a 4 year safety study. Adverse events (AEs) and spirometry data were used to assess long-term safety out to 5 years post-BT.Results45 of 52 treated and 24 of 49 control group subjects participated in long-term follow-up of 5 years and 3 years respectively. The rate of respiratory adverse events (AEs/subject) was stable in years 2 to 5 following BT (1.2, 1.3, 1.2, and 1.1, respectively,). There was no increase in hospitalizations or emergency room visits for respiratory symptoms in Years 2, 3, 4, and 5 compared to Year 1. The FVC and FEV1 values showed no deterioration over the 5 year period in the BT group. Similar results were obtained for the Control group.ConclusionsThe absence of clinical complications (based on AE reporting) and the maintenance of stable lung function (no deterioration of FVC and FEV1) over a 5-year period post-BT in this group of patients with moderate to severe asthma support the long-term safety of the procedure out to 5 years.

Recommendations for the use of bronchial thermoplasty in the management of severe asthma

“…The clinical effectiveness of BT has been confirmed in two prospective cohort feasibility studies, [14,22] three randomised controlled trials (RCTs), [23][24][25] one of which was published in the New England Journal of Medicine, and three prospective cohort followup studies interrogating long-term outcomes and safety [26][27][28] (the relevant studies are summarised in Table 1). The AIR trial enrolled 112 patients with moderate to severe asthma (FEV 1 60 -85% of predicted).…”

“…The long-term safety of BT (up to 5 years) has been demonstrated in three studies. [26][27][28] There is no consistent evidence that BT is causally associated with bronchial stenosis or bronchiectasis. In the AIR2 follow-up study, only three of 93 patients developed new (n=1) or worsening bronchiectasis (n=2) as shown on HRCT; it remains unclear whether this was a complication of asthma or related to BT.…”

Severe refractory asthma: an update

“…Other studies did not confirm these results but showed a decrease in the rate of asthma exacerbations and hospitalisations [100]. No clinical complications were observed in the long run, and pulmonary function remained stable over a period of 5 years [101]. Therefore, this approach might be a reasonable option for patients not responding to current treatment.…”

Bronchial thermoplasty: a non‐pharmacological approach

“…There was no deterioration in lung function for 5 years after BT, making the conclusion that it is safe for 5 years in severe asthma patients. In another follow-up study, 45 of 52 treated and 24 of 49 control group subjects who participated in AIR1 trial were selected for long-term follow-up of 5 years and 3 years, respectively (25). The rate of respiratory adverse events in the BT group (AEs/subject) remained stable in years 2-5 following BT.…”