Abstract
Background: International asthma guidelines recommend inhaled corticosteroid (ICS)/formoterol in preference to short-acting beta2-agonist (SABA) reliever-based regimens as reliever therapy in adults and adolescents of all asthma severities. A major limitation to this recommendation is the absence of randomised controlled trial (RCT) efficacy and safety data for this approach in patients who continue to use maintenance ICS. The anti-inflammatory effect of ICS/formoterol reliever therapy on airway inflammation is also not well characterised.
Objective: To determine the anti-inflammatory effect, efficacy and safety of budesonide-formoterol reliever therapy versus terbutaline reliever therapy in adults with asthma on maintenance ICS therapy. Fractional exhaled nitric oxide (FeNO) will specifically be examined to determine the time-course and magnitude of anti-inflammatory effect.
Methods: A 26-week, open-label, parallel-group, 2-arm, phase IV, two-sided superiority RCT will recruit 180 adults aged 16–75 with a clinical diagnosis of asthma using reliever only therapy, or SABA reliever therapy with maintenance ICS at baseline, and with baseline FeNO at screening ≥25 ppb. Enrolled participants will be allocated to maintenance budesonide with the dose based on their baseline treatment step and randomised 1:1 to either budesonide-formoterol or terbutaline reliever therapy. All participants will perform at home FeNO measurements at regular intervals for the first 12 weeks of the study. The primary outcome is FeNO at 26 weeks. Key secondary outcomes include FeNO time-course, asthma exacerbations, asthma control and spirometry.
Conclusion: This will be the first RCT comparing ICS-formoterol versus SABA reliever therapy in patients who use maintenance ICS therapy.