This review provides general information to serve as a primer for those embarking on understanding food allergy and also details advances and updates in epidemiology, pathogenesis, diagnosis, and treatment that have occurred over the 4 years since our last comprehensive review. Although firm prevalence data are lacking, there is a strong impression that food allergy has increased, and rates as high as approximately 10% have been documented. Genetic, epigenetic, and environmental risk factors are being elucidated increasingly, creating potential for improved prevention and treatment strategies targeted to those at risk. Insights on pathophysiology reveal a complex interplay of the epithelial barrier, mucosal and systemic immune response, route of exposure, and microbiome among other influences resulting in allergy or tolerance. The diagnosis of food allergy is largely reliant on medical history, tests for sensitization, and oral food challenges, but emerging use of component-resolved diagnostics is improving diagnostic accuracy. Additional novel diagnostics, such as basophil activation tests, determination of epitope binding, DNA methylation signatures, and bioinformatics approaches, will further change the landscape. A number of prevention strategies are under investigation, but early introduction of peanut has been advised as a public health measure based on existing data. Management remains largely based on allergen avoidance, but a panoply of promising treatment strategies are in phase 2 and 3 studies, providing immense hope that better treatment will be imminently and widely available, whereas numerous additional promising treatments are in the preclinical and clinical pipeline.

Food allergy: A review and update on epidemiology, pathogenesis, diagnosis, prevention, and management.

BACKGROUND Peanut allergy, for which there are no approved treatment options, affects patients who are at risk for unpredictable and occasionally life-threatening allergic reactions. METHODS In a phase 3 trial, we screened participants 4 to 55 years of age with peanut allergy for allergic dose-limiting symptoms at a challenge dose of 100 mg or less of peanut protein (approximately one third of a peanut kernel) in a double-blind, placebo-controlled food challenge. Participants with an allergic response were randomly assigned, in a 3:1 ratio, to receive AR101 (a peanut-derived investigational biologic oral immunotherapy drug) or placebo in an escalating-dose program. Participants who completed the regimen (i.e., received 300 mg per day of the maintenance regimen for approximately 24 weeks) underwent a double-blind, placebo-controlled food challenge at trial exit. The primary efficacy end point was the proportion of participants 4 to 17 years of age who could ingest a challenge dose of 600 mg or more, without dose-limiting symptoms. RESULTS Of the 551 participants who received AR101 or placebo, 496 were 4 to 17 years of age; of these, 250 of 372 participants (67.2%) who received active treatment, as compared with 5 of 124 participants (4.0%) who received placebo, were able to ingest a dose of 600 mg or more of peanut protein, without dose-limiting symptoms, at the exit food challenge (difference, 63.2 percentage points; 95% confidence interval, 53.0 to 73.3; P<0.001). During the exit food challenge, the maximum severity of symptoms was moderate in 25% of the participants in the active-drug group and 59% of those in the placebo group and severe in 5% and 11%, respectively. Adverse events during the intervention period affected more than 95% of the participants 4 to 17 years of age. A total of 34.7% of the participants in the active-drug group had mild events, as compared with 50.0% of those in the placebo group; 59.7% and 44.4% of the participants, respectively, had events that were graded as moderate, and 4.3% and 0.8%, respectively, had events that were graded as severe. Efficacy was not shown in the participants 18 years of age or older. CONCLUSIONS In this phase 3 trial of oral immunotherapy in children and adolescents who were highly allergic to peanut, treatment with AR101 resulted in higher doses of peanut protein that could be ingested without dose-limiting symptoms and in lower symptom severity during peanut exposure at the exit food challenge than placebo. (Funded by Aimmune Therapeutics; PALISADE ClinicalTrials.gov number, NCT02635776 .).

https://findresearcher.sdu.dk:8443/ws/files/158746853/nejmoa1812856.pdf

AR101 Oral Immunotherapy for Peanut Allergy

Allergen immunotherapy (AIT) has been used to treat allergic disease since the early 1900s. Despite numerous clinical trials and meta-analyses proving AIT efficacious, it remains underused and is estimated to be used in less than 10% of patients with allergic rhinitis or asthma worldwide. In addition, there are large differences between regions, which are not only due to socioeconomic status. There is practically no controversy about the use of AIT in the treatment of allergic rhinitis and allergic asthma, but for atopic dermatitis or food allergy, the indications for AIT are not well defined. The elaboration of a wider consensus is of utmost importance because AIT is the only treatment that can change the course of allergic disease by preventing the development of asthma and new allergen sensitizations and by inducing allergen-specific immune tolerance. Safer and more effective AIT strategies are being continuously developed both through elaboration of new allergen preparations and adjuvants and alternate routes of administration. A number of guidelines, consensus documents, or both are available on both the international and national levels. The international community of allergy specialists recognizes the need to develop a comprehensive consensus report to harmonize, disseminate, and implement the best AIT practice. Consequently, the International Collaboration in Asthma, Allergy and Immunology, formed by the European Academy of Allergy and Clinical Immunology; the American Academy of Allergy, Asthma & Immunology; the American College of Allergy, Asthma & Immunology; and the World Allergy Organization, has decided to issue an international consensus on AIT.

International consensus on allergy immunotherapy

Background Coadministration of a bacterial adjuvant with oral immunotherapy (OIT) has been suggested as a potential treatment for food allergy. Objective To evaluate a combined therapy comprising a probiotic together with peanut OIT. Methods We performed a double-blind, placebo-controlled randomized trial of the probiotic Lactobacillus rhamnosus CGMCC 1.3724 and peanut OIT (probiotic and peanut oral immunotherapy [PPOIT]) in children (1-10 years) with peanut allergy. The primary outcome was induction of sustained unresponsiveness 2 to 5 weeks after discontinuation of treatment (referred to as possible sustained unresponsiveness). Secondary outcomes were desensitization, peanut skin prick test, and specific IgE and specific IgG 4 measurements. Results Sixty-two children were randomized and stratified by age (≤5 and >5 years) and peanut skin test wheal size (≤10 and >10 mm); 56 reached the trial's end. Baseline demographics were similar across groups. Possible sustained unresponsiveness was achieved in 82.1% receiving PPOIT and 3.6% receiving placebo ( P P 4 levels (all P Conclusion This is the first randomized placebo-controlled trial evaluating the novel coadministration of a probiotic and peanut OIT and assessing sustained unresponsiveness in children with peanut allergy. PPOIT was effective in inducing possible sustained unresponsiveness and immune changes that suggest modulation of the peanut-specific immune response. Further work is required to confirm sustained unresponsiveness after a longer period of secondary peanut elimination and to clarify the relative contributions of probiotics versus OIT.

Administration of a probiotic with peanut oral immunotherapy: A randomized trial

Food allergy can result in considerable morbidity, impairment of quality of life, and healthcare expenditure. There is therefore interest in novel strategies for its treatment, particularly food allergen immunotherapy (FA-AIT) through the oral (OIT), sublingual (SLIT), or epicutaneous (EPIT) routes. This Guideline, prepared by the European Academy of Allergy and Clinical Immunology (EAACI) Task Force on Allergen Immunotherapy for IgE-mediated Food Allergy, aims to provide evidence-based recommendations for active treatment of IgE-mediated food allergy with FA-AIT. Immunotherapy relies on the delivery of gradually increasing doses of specific allergen to increase the threshold of reaction while on therapy (also known as desensitization) and ultimately to achieve post-discontinuation effectiveness (also known as tolerance or sustained unresponsiveness). Oral FA-AIT has most frequently been assessed: here, the allergen is either immediately swallowed (OIT) or held under the tongue for a period of time (SLIT). Overall, trials have found substantial benefit for patients undergoing either OIT or SLIT with respect to efficacy during treatment, particularly for cow's milk, hen's egg, and peanut allergies. A benefit post-discontinuation is also suggested, but not confirmed. Adverse events during FA-AIT have been frequently reported, but few subjects discontinue FA-AIT as a result of these. Taking into account the current evidence, FA-AIT should only be performed in research centers or in clinical centers with an extensive experience in FA-AIT. Patients and their families should be provided with information about the use of FA-AIT for IgE-mediated food allergy to allow them to make an informed decision about the therapy.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/all.13319

Loraine Foley

Papers

Assessing the efficacy of oral immunotherapy for the desensitisation of peanut allergy in children (STOP II): a phase 2 randomised controlled trial