Study of induction of Tolerance to Oral Peanut: a randomised controlled trial of desensitisation using peanut oral immunotherapy in children (STOP II)

Study of induction of Tolerance to Oral Peanut: a randomised controlled trial of desensitisation using peanut oral immunotherapy in children (STOP II) Katherine Anagnostou,1 Sabita Islam,1 Yvonne King,2 Loraine Foley,2 Laura Pasea,3 Chris Palmer,3 Simon Bond,4 Pamela Ewan1 and Andrew Clark1* 1Department of Medicine, University of Cambridge, Addenbrooke’s Hospital, Cambridge, UK 2Department of Allergy, Addenbrooke’s Hospital, Cambridge, UK 3Centre for Applied Medical Statistics, Department of Public Health and Primary Care, University of Cambridge, Institute of Public Health, Cambridge, UK 4Cambridge Clinical Trials Unit, Cambridge University Hospitals NHS Foundation Trust, Addenbrooke’s Hospital, Cambridge, UK *Corresponding author atclark@doctors.org.uk Background: Peanut allergy is a common disease that causes severe and fatal food allergic reactions. Currently, the best treatment is avoidance as repeated reactions can occur. Quality of life (QoL) is reduced by fear of severe reactions and social limitations. Oral immunotherapy (OIT) is a novel treatment that may be an effective treatment for peanut allergy. Objectives: To determine the efficacy of peanut OIT in children. Design: A phase 2 randomised, controlled, crossover trial (open label). Setting: Single UK centre study. Participants: Children aged 7–15 years with peanut allergy diagnosed by double-blind, placebo-controlled food challenge (DBPCFC). No children were excluded because of anaphylaxis or asthma. Interventions: Daily immunotherapy (2 mg, 5mg, 12.5mg, 25mg, 50mg, 100mg, 200mg, 400mg and 800mg of peanut protein) was administered as peanut flour (containing 50% peanut protein). Doses were increased at 2-weekly intervals to a maintenance dose of 800mg of protein. The control group underwent peanut avoidance for 6 months during phase 1. Main outcome measure: A peanut DBPCFC up to 1400mg of peanut protein was performed in both groups at 6 months. The highest amount of peanut tolerated was the main outcome measure. Randomisation: Randomised by online audited system to active or control group (1 : 1). Blinding: The intervention arm allocation was not blinded. Methods: We assigned 99 participants aged 7–16 years with peanut allergy of all severities to active OIT or control (peanut avoidance/current standard of care). The primary outcome was desensitisation, defined as negative peanut challenge (1400mg of protein DBPCFC) at 6 months (phase 1). Control participants underwent OIT during phase 2, followed by DBPCFC. Immunological parameters and disease-specific QoL scores were measured. DOI: 10.3310/eme01040 EFFICACY AND MECHANISM EVALUATION 2014 VOL. 1 NO. 4 © Queen’s Printer and Controller of HMSO 2014. This work was produced by Anagnostou et al. under the terms of a commissioning contract issued by the Secretary of State for Health. This issue may be freely reproduced for the purposes of private research and study and extracts (or indeed, the full report) may be included in professional journals provided that suitable acknowledgement is made and the reproduction is not associated with any form of advertising. Applications for commercial reproduction should be addressed to: NIHR Journals Library, National Institute for Health Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK. v Results: The primary outcome, desensitisation, was observed in 62% (24/39) of the active group and none (0/46) of the control group after phase 1 [95% confidence interval (CI) 45% to 78% vs. 0% to 9%; p< 0.001]; 84% (95% CI 70% to 93%) of the active group tolerated daily ingestion of 800mg of protein (≈ five peanuts). Median increase in peanut threshold after OIT was 1345mg (range 45–1400mg; p< 0.001) or 2.5-fold (range 1.82–280-fold; p< 0.001). After phase 2, 54% (95% CI 35% to 72%) tolerated a 1400-mg challenge (≈ 10 peanuts) and 91% (95% CI 79% to 98%) tolerated a daily ingestion of 800mg of protein. QoL scores improved (decreased) after OIT (median change –1.61; p< 0.001). Side effects were mostly mild with gastrointestinal symptoms being the most common: oral pruritus occurred after 6.3% of doses, wheeze occurred after 0.41% of doses (one-fifth of participants) and intramuscular epinephrine was required after 0.01% of doses (one participant). Conclusion: In children with peanut allergy of any severity, OIT successfully induced desensitisation in the majority, with a clinically meaningful increase in peanut threshold. QoL improved after intervention and there was a good safety profile. Immunological changes reflected clinical desensitisation. Peanut OIT should not be undertaken in non-specialist settings. Future work will include a phase 3 confirmatory study and studies of long-term tolerance; similar studies of other allergens are also required. Trial registration: Current Controlled Trials ISRCTN62416244. Funding: This project was awarded by the Efficacy and Mechanism Evaluation programme and is funded by the Medical Research Council (MRC) and managed by the National Institute for Health Research (NIHR) on behalf of the MRC–NIHR partnership, and jointly sponsored by the University of Cambridge and Addenbrooke’s Hospital [Cambridge University Hospital Foundation Trust (RD authorisation A091686)]. The project will be published in full in Efficacy and Mechanism Evaluation; Vol. 1, No. 4. See the NIHR Journals Library website for further project information. ABSTRACT NIHR Journals Library www.journalslibrary.nihr.ac.uk vi