Evaluating allergy status following peanut oral immunotherapy in the NATASHA Randomised Controlled Trial

Research question Is peanut-OIT more effective at inducing "remission" (where desensitisation persists without the need for daily dosing) in younger, preschool-aged children compared to older children in the UK setting? Background Food allergy affects 1 in 30 children, and is a major public health issue. It is the commonest cause of potentially life-threatening anaphylaxis in children/young people. Anxiety over the risk of reaction has a profound negative impact on health-related quality-of-life (HRQL) in affected individuals and their families. Oral immunotherapy (OIT) has emerged as a treatment option, and has revolutionised our approach to managing people with established food allergies. Immunotherapy modifies the immune response to allergen exposure (desensitisation), reducing the risk of allergic reaction following treatment. However, for most patients, daily maintenance dosing is required. Despite high patient demand, widespread implementation of OIT in the NHS has been limited by the need for longer-term (even lifelong) daily dosing to maintain treatment effect. This can be a treatment barrier, as most allergic people remain averse to the taste of the food they are allergic to. Some individuals develop sufficient immune modification after 3 years of treatment to achieve "remission", allowing them to stop daily dosing. This reduces treatment burden for patients and families and the need for clinical follow-up, releasing further resource to offer the treatment to more people. Remission may be more common in younger, preschool-aged children - but this has not been tested in a head-to-head study. Identifying those individuals who achieve remission with treatment will enable us to target the treatment to patients in the most effective way in the NHS. Aims and Objectives 1) Evaluate the rate of remission after 3 years of peanut-OIT, and whether this this differs in preschool-aged versus older children. 2) Assess the safety of peanut-OIT (including rates of accidental reactions, and their severity) for up to 3 years following treatment. 3) Determine the cost-effectiveness of peanut-OIT in the NHS. Methods 178 participants (over 1/3 non-Caucasian) aged 2–23 years who are currently undergoing peanut-OIT in the NATASHA study will be evaluated after 3 years of treatment. Specifically, we will assess a new treatment outcome of "remission", by offering in-hospital food challenges 1 and 3 months after stopping treatment. Our patient partners tell us this outcome is key to supporting their initial decision to undertake treatment. We will evaluate the impact of age on remission, and using these data, assess impact on cost-effectiveness. Timelines for delivery The 3-year assessments will take place between April 2026 and January 2029. Anticipated Impact and Dissemination If OIT is more successful in younger children, this will justify a radical shift towards performing OIT in younger children, reducing future healthcare needs and improving cost-effectiveness. This study will therefore guide implementation of OIT in the UK – specifically which patients are more likely to achieve remission – and inform clinical guidelines. Dissemination will be prioritised through professional societies, patient charities and peer-reviewed publications, as well as through media channels supported by the Natasha Allergy Research Foundation (https://www.narf.org.uk/).