Impact of biologic therapy on ICS/LABA adherence in severe asthma: assessment of inhaler therapy adherence remains imperative

Rationale Poor adherence to inhaled corticosteroids (ICSs) is often overlooked in severe asthma (SA), yet remains critical for treatment success. This study assesses electronically measured ICS/long-acting-beta-agonist (LABA) adherence and inhalation technique after biologic initiation in SA patients.Methods This study is a sub-study derived from the EXACT@home study, a prospective, single-center randomized control trial. ICS/LABA treatments for SA patients initiating biologic therapy were switched to BF-Digihaler (Teva®), a digital inhaler containing budesonide/formoterol, to monitor adherence and technique over a 6-month period. Adequate adherence was defined as using the correct dosage and achieving adequate inhalation flow on ≥80% of days, excluding underuse and overuse.Results Fourteen patients were included (mean age 54 ± 11 years; 35.7% female). Median weekly adherence was 100% [43–100%] at baseline (week 2) and decreased to 73% [40–100%] at follow-up (week 27) (p = 0.153). Four patients had a weekly adherence rate below 80% at baseline, and seven had a rate below 80% at follow-up. A decrease in adherence of ≥10% was observed in six patients. There was a significant positive correlation between adherence and ACQ at follow-up (Spearman’s ρ = 0.698, p = 0.006). Decrease in adherence was primarily due to reduced medication use, rather than worsened inhalation technique.Conclusions Even among patients with SA who have started biologic therapy, adherence to ICS/LABA is crucial in treatment optimization and may decrease over time. This highlights the importance of ongoing adherence monitoring and support following biologics initiation to ensure optimal asthma control in SA patients.