PURPOSE:Bronchial thermoplasty (BT), is a novel bronchoscopic procedure designed to control asthma by reducing airway smooth muscle mass. Treated patients in three studies have completed follow-up out to at least 3 years. Safety data from the 3 studies are compared.
METHODS:BT-treated patients in the Feasibility, AIR and RISA Trials who have completed 3-year follow-up were included in the analyses. Feasibility Study patients required ICS to manage their asthma; AIR Trial patients required ICS ≥100μg fluticasone or equivalent+LABA, Pre-bronchodilator (Pre-BD) FEV1 ≥60% and ≤;85% predicted; and RISA Trial patients required ICS >750 μg fluticasone or equivalent+LABA, Pre-BD FEV1 ≥50% predicted. According to current NAEPP guidelines, Feasibility patients were considered mild to moderate in severity, AIR patients were considered moderate to severe and RISA patients were predominantly refractory. Adverse event (AE) and spirometry data from the 3 studies are used to assess long-term safety across studies.
RESULTS:The number of respiratory-related AEs per bronchoscopy was similar across all 3 studies following BT in patients with differing severity of asthma. However, the more severe disease was associated with higher number of “moderate” and “severe” AEs compared to the less severe asthmatics where more AEs were classified as “mild”. Respiratory-related AE’s requiring hospitalization occurred only in the AIR and RISA Trials. Beyond the treatment period, the number and severity of AE’s remained stable over the 3-year period in each of the study groups. Following BT, there was no deterioration in pulmonary function (FEV1 % predicted) over the 3 year period in the 3 studies. This is of interest particularly in the RISA subjects who underwent a steroid wean in the first year of study.
CONCLUSION:BT is associated with short-term AE’s that are related to the severity of the asthma being treated.
CLINICAL IMPLICATIONS:The absence of clinical complications (based on AE reporting) and presence of stable lung function (based on spirometry) over 3 years post-BT across 3 studies in a range of asthma severity, suggests that BT has a satisfactory long-term safety profile.
DISCLOSURE:Gerard Cox, Grant monies (from industry related sources) All clinical trials of Bronchial Thermoplasty have been exclusively supported by Asthmatx Inc.; Product/procedure/technique that is considered research and is NOT yet approved for any purpose. Bronchial Thermoplasty is a procedure with potential for treating asthma. It is not yet approved for clinical use in USA or Canada.