Physical Activity Promotion and Clinical Remission in Severe Asthma

Severe asthma is associated with persistent symptoms, reduced physical activity, impaired exercise capacity, and poor health-related quality of life despite advances in pharmacological management. Although biologic therapies such as tezepelumab have substantially improved asthma control and increased rates of clinical remission, many individuals continue to experience functional limitations and remain physically inactive. Physical inactivity has emerged as a potentially modifiable treatable trait associated with poorer clinical outcomes, suggesting that interventions targeting physical activity may complement biologic therapy and improve broader health outcomes. This multicentre, open-label, randomised controlled trial will evaluate whether a structured physical activity promotion programme delivered alongside standard treatment with tezepelumab increases objectively measured physical activity and improves clinical outcomes, including clinical remission, compared with standard care alone. Adults initiating tezepelumab as part of routine clinical care at participating UK severe asthma centres will be randomised in a 1:1 ratio to receive either standard care or standard care plus a 12-week physical activity promotion intervention. The physical activity intervention is informed by the Capability, Opportunity, Motivation-Behaviour (COM-B) framework and incorporates evidence-based behaviour change techniques including personalised goal setting, action planning, self-monitoring using a smartphone application, individual behavioural consultation, and six online group support sessions delivered over 12 weeks. Following completion of the intervention, participants will continue to be followed for a total of 12 months to evaluate the maintenance of behavioural and clinical outcomes. The primary outcome will be change in objectively measured daily step count from baseline to 3-months. The primary clinical outcome will be the proportion of participants achieving clinical remission on treatment at 12-months. Secondary outcomes include asthma disease stability at 3 and 12-months, defined as achievement of ≥2 clinical remission characteristics, annualised asthma exacerbation rate, objectively measured physical activity at 12-months, and functional exercise capacity. The study will also examine whether baseline clinical and behavioural characteristics are associated with response to the physical activity intervention. The findings will determine whether integrating structured physical activity promotion with biologic therapy provides additional clinical benefit beyond pharmacological treatment alone and may inform future remission-focused models of severe asthma care.