A study protocol for a randomised controlled trial of two stepwise pharmacological treatment approaches to adult asthma: inhaled corticosteroid/formoterol reliever- versus short-acting β2-agonist reliever-based therapy - Asthma on TRACK.

BACKGROUND: No randomised controlled trials (RCTs) have compared inhaled corticosteroid (ICS)/formoterol reliever-based stepwise algorithms with short-acting β-agonist (SABA) reliever-based stepwise algorithms, titrated to levels of asthma control and exacerbations. Knowledge gaps remain in understanding ICS exposure over time, transitions between treatment steps, efficacy and participant satisfaction with different algorithm approaches. OBJECTIVE: The aim of the study is to determine the exposure to ICS in adults and adolescents aged 16 to 75 years treated with a budesonide/formoterol reliever-based algorithm (Algorithm 1) compared to a salbutamol reliever-based algorithm (Algorithm 2) across the spectrum of asthma severity. METHODS: This is an investigator-initiated, 52-week, single-site, open-label, parallel-groups, 2-arm RCT of 152 adults and adolescents with mild, moderate and moderate-severe asthma (ACTRN12624001488594). Participants will be randomly allocated in a 1:1 ratio to a budesonide/formoterol reliever-based or a salbutamol reliever-based algorithm. Global Initiative for Asthma (GINA) treatment step at enrolment according to the 2024 GINA Guidelines will be used to allocate participants to the corresponding steps of each algorithm. Treatment step transition will be in response to asthma exacerbations and level of asthma control. Those experiencing exacerbations or poorly controlled asthma will be stepped up, and those well controlled stepped down. The primary outcome is ICS exposure. Important secondary outcomes include composite systemic corticosteroid exposure, rates of asthma exacerbations, asthma control, T-helper 2 biomarkers, spirometry and participants' treatment perceptions and satisfaction. CONCLUSION: This is the first RCT to compare ICS/formoterol- and SABA-based reliever stepwise algorithmic approaches in asthma, with treatment adjusted according to asthma control and exacerbations.