S132 Ten-year efficacy and safety following bronchial thermoplasty for asthma – the BT10+ study

Background Bronchial thermoplasty (BT) is a non-pharmacologic, endoscopic treatment for asthma not well controlled with long-acting b-agonists and inhaled corticosteroids. Long-term efficacy and safety of BT beyond 5 years is unknown. The BT10+ study was designed to evaluate the efficacy and safety of BT at 10+ years follow-up. Methods BT10+ is an international, multi-center, ≥10yrs follow-up study on subjects who were enrolled in the AIR, RISA and AIR2 BT trials. Demographics, quality of life, lung function, severe exacerbations (SE, defined as asthma exacerbations requiring systemic corticosteroids) and healthcare utilisation for the previous year were collected at the BT10+ study visit. Additionally, AIR2 subjects who received a pulmonary high-resolution CT (HRCT) at baseline had a second scan at the BT10+ study visit to determine if clinically relevant changes, such as bronchiectasis, occur after BT. Results Of 429 subjects enrolled AIR, RISA, and AIR2, 192 were followed-up at 10.6–15.8 years (12.1 median) post-treatment at 16 centers; of these, 136 were treated with BT and 38 were control/sham subjects in previous studies. Baseline characteristics between subjects enrolled and not enrolled in BT10+ did not show meaningful differences. For BT subjects, no increases in the rate of hospitalisations or ER visits were observed compared to baseline and rates of SE were stable compared to Year 1 (figure 1). While both groups experienced fewer SE after treatment, BT subjects had fewer SE than control/sham subjects at the BT10+ visit; this was not significant. Quality of life (AQLQ, ACQ) and spirometry results were comparable between Years 1, 5, and 10+ for both groups. Pulmonary HRCT scans from AIR2 subjects at the BT10+ study visit showed 9.5% (2/21) of control/sham subjects and 13.4% (13/97) of BT subjects had bronchiectasis; however, when these were compared with baseline HRCT scans, only 5.3% (5/94) of BT subjects had developed bronchiectasis after their baseline visit. Conclusion The BT10+ study suggests that efficacy of BT is sustained over 10 years and that BT has an acceptable safety profile.