1-year results of bronchial thermoplasty in refractory asthma

Asthmatx, Inc. has announced the publication of data from the Research in Severe Asthma (RISA) Trial of bronchial thermoplasty in the American Journal of Respiratory and Critical Care Medicine (AJRCCM, 2007; 176:1185-1191).

The publication reports that despite a transient increase in procedure related adverse events, patients experienced longer term improvement in pulmonary function, improved quality of life and asthma control, and a reduction in rescue medication use for patients treated with bronchial thermoplasty.

Bronchial thermoplasty is a non-drug treatment for asthma and is currently under clinical investigation. Bronchial thermoplasty is an investigational procedure in which precisely controlled thermal energy is delivered with a tiny catheter to targeted airway walls of patients with asthma. This procedure is intended to reduce muscle in the walls of airways, and thereby decrease the ability of airways to narrow in patients with symptomatic asthma.

The RISA Trial was a randomized trial conducted at a total of eight centers in three countries, and evaluated the safety and efficacy of bronchial thermoplasty in a total of 32 adult subjects, randomized 1:1 between the BT group and Control group with severe persistent asthma who were symptomatic despite taking regular asthma medications.

In this group of patients with severe asthma, an increase in respiratory-related symptoms was expected and observed during the period immediately following the procedure. Most occurred within one day of the procedure and resolved on average within a week. Following the treatment period, respiratory-related symptoms were similar between treatment groups.

Almost 6 months after the procedure, compared to the control group, patients who received bronchial thermoplasty showed clinically and statistically significant improvements in pulmonary function, quality of life and asthma control. In addition, patients in the treatment group used an average of 25 fewer puffs per week of rescue medication than those in the untreated Control group.

All patients then attempted to reduce their inhaled and/or oral corticosteroids (OCS) during a 14 week period. Fifty percent (50%) of bronchial thermoplasty treated patients were able to wean completely off their oral corticosteroids (OCS), compared to 14% of patients who did not receive the treatment. This improvement did not reach statistical significance; however the study was not powered to show statistical significance in medication changes.

One year following treatment, and after the period of medication reduction, patients who received the bronchial thermoplasty procedure continued to show clinically and statistically significant improvements in quality of life and asthma control, and used less rescue medication .

“We found that, in this population of severe asthma patients, bronchial thermoplasty was associated with a short-term increase in asthma-related symptoms around the time of treatment but showed a potential for a longer-term improvement in rescue medication use, lung function, asthma control and quality of life,” states Ian D. Pavord, MD and principle investigator of the study at the Glenfield General Hospital, University Hospitals of Leicester. “These potential long term improvements make us hopeful that bronchial thermoplasty could some day be a viable new treatment option for these severe asthma patients.”