Bronchial Thermoplasty Reduces Airway Smooth Muscle Mass in Severe Asthma

A significantly greater reduction in airway smooth muscle (ASM) mass was observed in patients with severe asthma who underwent immediate bronchial thermoplasty compared with those who did not, according to study results published in American Journal of Respiratory and Critical Care Medicine. Additionally, levels of serum immunoglobulin E (IgE) and eosinophils may predict response to bronchial thermoplasty.

A total of 40 patients with severe asthma were recruited to the TASMA (Unravelling Targets of Therapy in Bronchial Thermoplasty in Severe Asthma; ClinicalTrials.gov Identifier: NCT02225392) trial between 2014 and 2018 at 2 centers in the Netherlands and 2 centers in the United Kingdom. Patients were randomly assigned to receive either immediate endoscopy treatment with bronchial thermoplasty (n=20) or delayed bronchial thermoplasty (control group; n=20).

Patients in the delayed therapy group underwent reassessment after 6 months of standard clinical care, which was then followed by bronchial thermoplasty. Post-treatment data, including blood and airway biopsies, were collected at 6 months and compared with data obtained prior to randomization.

In addition to calculating patients’ ASM mass following treatment, the investigators also examined associations between baseline clinical characteristics and improvement on the Asthma Control and Asthma Quality of Life Questionnaire (ACQ/AQLQ) to assess clinical response to treatment.

There were no device-related complications associated with bronchial thermoplasty. Compared with patients in the delayed group, patients in the immediate treatment group experienced a significantly greater decrease in the median ASM mass (median difference, -5.0; P =.0004). A significantly greater improvement was observed in scores on the ACQ in the immediate group vs the delayed group (-0.79 vs 0.09, respectively; P =.006). Additionally, the immediate treatment group experienced an improvement of 0.83 in AQLQ scores compared with -0.02 in the delayed group (P =.04).

In both groups, levels of serum IgE (P =.001) and eosinophils (P =.006) were positively associated with improvements on the ACQ. Only blood eosinophil counts were positively associated with AQLQ change (P =.004).

Study limitations included the small size of the cohort as well as the inclusion of patients with higher ACQ and lower AQLQ baseline scores in the immediate treatment group.

According to their secondary findings, the investigators added that this study suggests “that patients with high blood eosinophil counts and/or IgE levels are more likely to respond to” treatment with bronchial thermoplasty.

Disclosure: This clinical trial was partially supported by Boston Scientific. Please see the original reference for a full list of authors’ disclosures.

Reference

Goorsenberg AWM, d’Hooghe JNS, Srikanthan K, et al; on behalf of the TASMA research group. Bronchial thermoplasty-induced acute airway effects assessed with optical coherence tomography in severe asthma: the TASMA randomized trial. Am J Respir Crit Care Med. Published online July 28, 2020. doi:10.1164/rccm.201911-229OC