Bronchial Thermoplasty Benefits For Uncontrolled Asthma Sustained At 10 Years

The benefits of bronchial thermoplasty in patients with uncontrolled asthma are sustained over at least 10 years, according to results of the BT10+ study.

Bronchial thermoplasty was approved in the United States in 2010 for patients aged 18 years and older with severe persistent asthma refractory to inhaled corticosteroids and long-acting beta-agonists.

During the endoscopic procedure, controlled radiofrequency energy heats the airway walls to reduce airway smooth muscle mass.

In the AIR, RISA, and AIR2 randomized controlled trials, bronchial thermoplasty led to improvements in asthma control up to five years after treatment, as shown by decreased numbers of asthma exacerbations, trips to the emergency department and hospital admissions, as well as improved quality of life.

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For the BT10+ study, Dr. Rekha Chaudhuri of Gartnavel General Hospital, in Glasgow, U.K., and colleagues reconnected with 136 participants in these trials who received bronchial thermoplasty (52% of the 260 original patients who underwent thermoplasty) at least 10 years previously. They successfully did the same for 56 sham (control) participants (33% of 169 from the original trials).

The results showed sustained improvement in severe exacerbations and healthcare for 10 or more years out from bronchial thermoplasty. At the BT10+ study visit, the rates of severe exacerbations and emergency department visits were higher compared with at year 5, but the positive effect compared with baseline was sustained, as was the improvement in asthma-related quality of life measures up to 10 years.

There was no suggestion that bronchial thermoplasty caused any impairment of lung function. On the contrary, there was a suggestion that bronchial thermoplasty preserved lung function over time compared with expected age-related deterioration, based on FEV1 measurements.

Six patients (7%) treated with bronchial thermoplasty developed radiological evidence of bronchiectasis, which was characterized as mild in all but one case, and was not accompanied by clinical symptoms such as cough, sputum, or recurrent infection.

It's not clear whether bronchiectasis was due to bronchial thermoplasty, the researchers note in their article. "An alternative explanation for the slight increase in participants with bronchiectasis at the BT10+ study visit could be related to improvements in both CT hardware and image processing algorithms developed over the past decade that could result in better detection of mild bronchiectasis compared with older images," they write.

Summing up, they say the data from the BT10+ study indicate that the efficacy of bronchial thermoplasty is sustained for 10 or more years and that bronchial thermoplasty has an acceptable safety profile.

In a Comment published with the study in The Lancet Respiratory Medicine, Dr. David Langton of Monash University, in Melbourne, Australia, notes that 10-year follow-up studies are a "rare commodity in respiratory medicine and the authors should be congratulated for their study."

"As a novel, endoscopic treatment for asthma, bronchial thermoplasty has long been regarded by clinicians with caution. This caution partly stems from it being an irreversible surgical treatment by comparison with the more traditional approach to asthma therapy with pharmaceuticals (which can be discontinued if necessary)," Dr. Langton notes.

"The past 10 years have seen monumental steps forward in the management of severe asthma, chiefly due to the advent of monoclonal antibody therapy. However, patients with Th-2 low asthma have been left behind in the rush, for whom only macrolide therapy has shown promise, and only then in short-term studies. Bronchial thermoplasty shows its greatest application in such patients. This study by Chaudhuri and colleagues provides both hope and reassurance for these patients and their clinicians," he concludes.

The BT10+ study was funded by Boston Scientific. Several authors report ties to the company.

—Reuters Staff

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