Study | Features | Duration weeks | Assessments | Inclusion criteria | Subjects n | Control |
RISA [5] | Multicentre, randomised, parallel groups | 52 | Changes: ICS, OCS, PEFR, FEV1, AQLQ, safety | Age 18–65 years, ICS >750 μg, FP+LABA, pre-BD FEV1 ≥50% pred, uncontrolled | 32 | Continue usual ICS+LABA |
AIR [6] | Multicentre, randomised, parallel groups | 52 | Changes: ICS, OCS, rescue β2 agonists, exacerbations, PEFR, FEV1, AQLQ, safety during LABA withdrawal periods | Age 18–65 years, ICS ≥200 μg, BDP+LABA, pre-BD FEV1 60–85% pred | 109 | Continue usual ICS+LABA |
AIR2 [7] | Multicentre, randomised, placebo, double-blind, parallel groups | 52 | Number of asthma-free days, exacerbations (admissions, urgent care), rescue β2 agonists, PEFR, FEV1, AQLQ, absenteeism, safety | Age 18–65 years, ICS >1000 μg, BDP+LABA, pre-BD FEV1 ≥60% pred | 288 | Three sham sessions of bronchial thermoplasty every 3 weeks, continue usual ICS+LABA |
RISA: Research in Severe Asthma; AIR: Asthma Intervention Research; ICS: inhaled corticosteroids; OCS: oral corticosteroids; PEFR: peak expiratory flow rate; FEV1: forced expiratory volume in 1 s; AQLQ: Asthma Quality of Life Questionnaire; FP: fluticasone propionate; LABA: long-acting β2-agonist; BD: bronchodilator; BDP: beclomethasone dipropionate. For all three studies, thermoplasty treatment consisted of three sessions of bronchial thermoplasty every 3 weeks, while continuing usual ICS+LABA.