Clinical response of severe asthma patients following Bronchial Thermoplasty

Background: Bronchial Thermoplasty (BT) is a novel bronchoscopic treatment for severe asthma. The response rate of BT and the specific phenotype benefitting from BT treatment is under discussion. AIMS Determine the clinical response rate following BT treatment and to identify responder characteristics. Methods: Before and 6 months after BT treatment the following outcome variables where obtained in 11 severe asthma patients (TASMA No. NCT02225392): asthma control (ACQ), quality of life (AQLQ), asthma exacerbation rate, blood eosinophils, IgE, spirometry, bronchial hyper responsiveness and airway smooth muscle (ASM) mass % in airway biopsies. Clinical responders rates were based on a minimal clinical important difference of >0.5 points in ACQ and AQLQ. Results: From 11 included patients, 55% (n=6) where classified as clinical responders with a median (range) change of the ACQ and AQLQ of -1.13 (-0.83 to -2.84) and 1.54 (0.72 to 2.57) respectively. Clinical responders (n=6) demonstrated a higher change in ASM% (median, range) than non-responders (n=5): - 60 (-28 to - 94)% vs -46 (-43 to 88)% respectively (p=0.86). Reduction of the exacerbation was observed in 82% (n=9/11) of patients showing a change of exacerbation rate of (median, range) -3 (-1 to -23). A specific responder profile cannot be assessed as yet with the current sample size. Conclusions: BT treatment shows an improvement in quality of life and reduction of exacerbation rate in the majority of severe asthma patients. A large reduction in ASM mass % is seen both in responders and non-responders.