Assessing inhaled corticosteroid adherence and responsiveness in severe asthma using beclometasone dipropionate/formoterol NEXThaler™ dose-counting and nitric oxide monitoring

Background 65% of people with severe asthma and a FeNO ≥45 ppb are non-adherent to inhaled corticosteroids (ICS). Digital devices recording both time-of-use and inhaler technique identify non-adherence and ICS responsiveness but are not widely available. As the NEXThaler™ dose counter only activates at an inspiratory flow of 35 L/min, this may provide an alternative to identifying ICS responsiveness. Objective To assess ICS adherence and responsiveness in severe asthma using beclometasone/formoterol (200/6 mcg) NEXThaler™ (BFN) dose-counting. Methods Severe asthmatics with a FeNO ≥45 ppb were invited to use BFN in place of their usual ICS/long-acting β2-agonist (LABA). FeNO, ACQ6, lung function and blood eosinophil count were monitored for 3 months. A log10ΔFeNO ≥0.24 was used to define FeNO suppression as the primary marker of ICS responsiveness at day 28. Results 27/48 (56%) patients demonstrated significant FeNO suppression at month 1 (median pre-114, post-48 ppb, p<0.001). A small but significant reduction occurred in FeNO non-suppressors. ACQ6 fell a median 1.2 units in FeNO suppressors (p<0.001) and 0.5 units in non-suppressors (p=0.025). These effects were sustained until month 3 in FeNO suppressors with a significant improvement in FEV1 and blood eosinophils. 67% (18/27) of those with baseline ICS/LABA prescription refills of ≥80% were FeNO suppressors suggesting prior non-adherence despite adequate prescription collection. 79% of FeNO suppressors did not require biologics within mean 11.4 months from initial dose counting. Conclusion BFN dose counting identifies ICS responsiveness in severe asthma with the implication that these patients may not need to progress to biological therapies.