Allergen-specific oral immunotherapy for peanut allergy (Review)

Allergy & Respiratory Research Group, Centre for Population Health Sciences, The University of Edinburgh, Edinburgh, UK.
Cochrane database of systematic reviews (Online) (Impact Factor: 6.03). 09/2012; 9(9):CD009014. DOI: 10.1002/14651858.CD009014.pub2
Source: PubMed


Peanut allergy is one of the most common forms of food allergy encountered in clinical practice. In most cases, it does not spontaneously resolve; furthermore, it is frequently implicated in acute life-threatening reactions. The current management of peanut allergy centres on meticulous avoidance of peanuts and peanut-containing foods. Allergen-specific oral immunotherapy (OIT) for peanut allergy aims to induce desensitisation and then tolerance to peanut, and has the potential to revolutionise the management of peanut allergy. However, at present there is still considerable uncertainty about the effectiveness and safety of this approach.
To establish the effectiveness and safety of OIT in people with IgE-mediated peanut allergy who develop symptoms after peanut ingestion.
We searched in the following databases: AMED, BIOSIS, CAB, CINAHL, The Cochrane Library, EMBASE, Global Health, Google Scholar, IndMed, ISI Web of Science, LILACS, MEDLINE, PakMediNet and TRIP. We also searched registers of on-going and unpublished trials. The date of the most recent search was January 2012.
Randomised controlled trials (RCTs), quasi-RCTs or controlled clinical trials involving children or adults with clinical features indicative of IgE-mediated peanut allergy treated with allergen-specific OIT, compared with control group receiving either placebo or no treatment, were eligible for inclusion.
Two review authors independently checked and reviewed titles and abstracts of identified studies and assessed risk of bias. The full text of potentially relevant trials was assessed. Data extraction was independently performed by two reviewers with disagreements resolved through discussion.
We found one small RCT, judged to be at low risk of bias, that enrolled 28 children aged 1 to 16 years with evidence of sensitisation to peanut and a clinical history of reaction to peanut within 60 minutes of exposure. The study did not include children who had moderate to severe asthma or who had a history of severe peanut anaphylaxis. Randomisation was in a 2:1 ratio resulting in 19 children being randomised to the intervention arm and nine to the placebo arm. Intervention arm children received OIT with peanut flour and control arm participants received placebo comprising of oat flour. The primary outcome was assessed using a double-blind, placebo controlled oral food challenge (OFC) at approximately one year. No data were available on longer term outcomes beyond the OFC conducted at the end of the study.Because of adverse events, three patients withdrew from the intervention arm before the completion of the study. Therefore, only 16 participants received the full course of peanut OIT, whereas all nine patients receiving placebo completed the trial. The per-protocol analysis found a significant increase in the threshold dose of peanut allergen required to trigger a reaction in those in the intervention arm with all 16 participants able to ingest the maximum cumulative dose of 5000 mg of peanut protein (which the authors equate as being equivalent to approximately 20 peanuts) without developing symptoms, whereas in the placebo group they were able to ingest a median cumulative dose of 280 mg (range: 0 to 1900 mg, P < 0.001) before experiencing symptoms. Per-protocol analyses also demonstrated that peanut OIT resulted in reductions in skin prick test size (P < 0.001), interleukin-5 (P = 0.01), interleukin-13 (P = 0.02) and an increase in peanut-specific immunoglobulin G(4) (IgG(4)) (P < 0.01).Children in the intervention arm experienced more adverse events during treatment than those in the placebo arm. In the initial day escalation phase, nine (47%) of the 19 participants initially enrolled in the OIT arm experienced clinically-relevant adverse events which required treatment with H(1)-antihistamines, two of which required additional treatment with epinephrine (adrenaline).
The one small RCT we found showed that allergen-specific peanut OIT can result in desensitisation in children, and that this is associated with evidence of underlying immune-modulation. However, this treatment approach was associated with a substantial risk of adverse events, although the majority of these were mild. In view of the risk of adverse events and the lack of evidence of long-term benefits, allergen-specific peanut OIT cannot currently be recommended as a treatment for the management of patients with IgE-mediated peanut allergy. Larger RCTs are needed to investigate the acceptability, long-term effectiveness and cost-effectiveness of safer treatment regimens, particularly in relation to the induction of clinical and immunological tolerance.

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Available from: Ulugbek Nurmatov, Jun 18, 2015
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    • "They concluded that peanut OIT represents a promising therapeutic approach for the management of peanut allergy. However, the evidence was not sufficient to draw conclusions regarding long-term effectiveness, safety and cost effectiveness of this intervention and it was not recommended for use in clinical practice [42]. "
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    ABSTRACT: Peanut allergy is common and can be a cause of severe, life-threatening reactions. It is rarely outgrown like other food allergies, such as egg and milk. Peanut allergy has a significant effect on the quality of life of sufferers and their families, due to dietary and social restrictions, but mainly stemming from fear of accidental peanut ingestion. The current management consists of strict avoidance, education and provision of emergency medication, but a disease- modifying therapy is needed for peanut allergy. Recent developments involve the use of immunotherapy, which has shown promise as an active form of treatment. Various routes of administration are being investigated, including subcutaneous, oral, sublingual and epicutaneous routes. Other forms of treatment, such as the use of vaccines and anti-IgE molecules, are also under investigation. So far, results from immunotherapy studies have shown good efficacy in achieving desensitisation to peanut with a good safety profile. However, the issue of long-term tolerance has not been fully addressed yet and larger, phase III studies are required to further investigate safety and efficacy. An assessment of cost/benefit ratio is also required prior to implementing this form of treatment. The use of immunotherapy for peanut allergy is not currently recommended for routine clinical use and should not be attempted outside specialist allergy units.
    09/2014; 4(1):30. DOI:10.1186/2045-7022-4-30
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    • "Early studies of oral immunotherapy (OIT) for peanut allergy have shown promise in inducing desensitization [8,9]. However, further investigation into the safety and efficacy profile is needed before peanut OIT can be recommended for clinical use [8,10]. Frequent and sometimes severe adverse allergic reactions have been observed during peanut OIT. "
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    ABSTRACT: Background Oral immunotherapy (OIT) has shown promise in inducing desensitization for food allergy. However, there are safety concerns regarding the frequency and severity of adverse events during food OIT. Objective To evaluate the effect of Ketotifen premedication on adverse reactions during peanut OIT. Methods A randomized single blind placebo controlled pilot study was performed. Peanut OIT was performed using a previously published protocol. Ketotifen was up-titrated to 2 mg twice daily over two weeks (week -2 to 0), followed by a peanut OIT initial escalation day (day 1). Ketotifen was administered from week 0–4 of peanut OIT; reactions to peanut OIT doses were recorded by clinic staff and subject diary. Results Six subjects (median age 10 years, peanut IgE >100kUA/L) were enrolled, 4 randomized to Ketotifen, 2 to placebo. The most common side effect of Ketotifen was fatigue (9% during up-titration). The rate of reaction per peanut OIT dose was lower for subjects on ketotifen (K) compared to placebo (P) during initial escalation on day 1 (K: 22% (8/36) vs. P: 67% (12/18)); week 0–4 build-up doses (K: 75% (3/4) vs. P: 100% (2/2)); and week 0–4 home doses (K: 50% (54/108) vs. P: 82% (27/33)). The rate of gastrointestinal symptoms per peanut OIT dose was also lower for subjects on ketotifen during initial escalation on day 1 (K: 17% (6/36) vs. P: 61% (11/18)); week 0–4 build-up doses (K: 75% (3/4) vs P: 100% (2/2)); and week 0–4 home doses (K: 46% (50/108) vs. P: 82% (27/33)). Conclusions Ketotifen premedication is well tolerated and reduces the rate of gastrointestinal symptoms during peanut OIT. These findings require confirmation in a larger study of Ketotifen premedication used throughout peanut OIT. Trial registration Clinical Trials number: NCT0162515
    Allergy Asthma and Clinical Immunology 07/2014; 10(1):36. DOI:10.1186/1710-1492-10-36 · 2.03 Impact Factor
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    • "Several prior studies have shown some success in using these approaches for single specific food allergens such as milk [8-15], egg [13,14,16-18], peanut [19-24], and hazelnut [25]. These current types of experimental treatments need to be tested for optimization in safety, efficacy, and length of time [26-34]. Safety is of critical importance at all phases of any protocol (initial dose escalation day, dose escalation, and maintenance phases) and allergic reactions while on OIT remain an important feature in long-term follow-up studies and in determining the overall success of food allergen immunotherapy [35]. "
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    ABSTRACT: Up to 30% of patients with food allergies have clinical reactivity to more than one food allergen. Although there is currently no cure, oral immunotherapy (OIT) is under investigation. Pilot data have shown that omalizumab may hasten the ability to tolerate over 4 g of food allergen protein. To evaluate the safety and dose tolerability of a Phase 1 Single Site OIT protocol using omalizumab to allow for a faster and safe desensitization to multiple foods simultaneously. Participants with multiple food allergies received OIT for up to 5 allergens simultaneously with omalizumab (rush mOIT). Omalizumab was administered for 8 weeks prior to and 8 weeks following the initiation of a rush mOIT schedule. Home reactions were recorded with diaries. Twenty-five (25) participants were enrolled in the protocol (median age 7 years). For each included food, participants had failed an initial double-blind placebo-controlled food challenge at a protein dose of 100 mg or less. After pre-treatment with omalizumab, 19 participants tolerated all 6 steps of the initial escalation day (up to 1250 mg of combined food proteins), requiring minimal or no rescue therapy. The remaining 6 were started on their highest tolerated dose as their initial daily home doses. Participants reported 401 reactions per 7,530 home doses (5.3%) with a median of 3.2 reactions per 100 doses. Ninety-four percent (94%) of reactions were mild. There was one severe reaction. Participants reached their maintenance dose of 4,000 mg protein per allergen at a median of 18 weeks. These phase 1 data demonstrate that rush OIT to multiple foods with 16 weeks of treatment with omalizumab could allow for a fast desensitization in subjects with multiple food allergies. Phase 2 randomized controlled trials are needed to better define safety and efficacy parameters of multi OIT experimental treatments with and without omalizumab.
    Allergy Asthma and Clinical Immunology 02/2014; 10(1):7. DOI:10.1186/1710-1492-10-7 · 2.03 Impact Factor
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