This year signified a rapid pace for emerging treatments of food allergy. We have now nearly a decade of research data on oral immunotherapy for food allergies. Oral immunotherapy refers to taking small escalating doses of the proteins in foods we are allergic to in order to induce tolerance of the allergen. Translating this to clinical practice as an option for treatment of food allergies is not far away.
A recent study for New England Journal of Medicine looked at AR101 (peanut-derived oral immunotherapy product) for peanut allergy. Participants from 4 to 55 years of age experienced allergic symptoms when they ingested 100 mg or less of a peanut protein (about a 1/3 of peanut kernel). Then, once peanut allergy was confirmed, patients were selected at random to receive either AR101 or placebo. Patients had to continue maintenance treatment of 300 mg of peanut protein (about 1 kernel) for 24 weeks. (1)
At the end of the study, patients were tested again to access the extent of their peanut allergy. 67% of patients who receive active treatment vs. 4% in the placebo group were able to ingest 600 mg of peanut protein (2 peanut kernels). What does this really mean for treatment of food allergies? We are still far from the cure for peanut allergy, but this is a really promising step forward! With the use of oral immunotherapy for peanut allergy, participants were able to increase their tolerance to peanut allergen. They went from having allergic reactions with exposure to minimal amounts of peanut to being able to tolerate about 2 peanuts. This can mean a world of difference for families who have dealt with potentially lifelong diagnosis of peanut allergy. FDA is expected to decide on AR101 for peanut allergy therapy as early as August of 2019.
The treatment comes with side effects. Allergic reactions during oral immunotherapy treatment are common and can range from mild symptoms to severe (anaphylactic) reactions that require the use of epinephrine. Nearly 60% of patients who were in the AR101 groups experienced allergic reactions that were rated as moderate and about 4% experienced severe events. This is certainly a mode of treatment that holds a lot of promise. However, this a not a mode of treatment to be taken lightly. Majority of treatment was given at home, so the possibility of breakthrough allergic reactions is definitely a factor to keep in mind. Some of the issues observed with oral immunotherapy include a risk of eosinophilic esophagitis, an allergic disease of the GI tract, where allergy cells called eosinophils create inflammation in the esophagus.
Another promising update is the use of a biological medication called omalizumab in the treatment of food allergies. Omalizumab or Xolair is an anti-IgE monoclonal antibody that could reduce the risk of allergic reactions during immunotherapy treatment. Thinks of it like a lock and key. Xolair is able to block allergic antibody IgE from triggering allergy cells in the body. It has been used for the treatment of allergic asthma and urticarial (hives). In the studies for food allergies, this medication looks promising in terms of allowing patients to increase doses of oral immunotherapy quickly (days or weeks vs. months!). (2)
Another possible solution to improve efficacy and safety of food OIT including starting earlier in life when the immune system could be more responsive to treatment. So starting treatment earlier can have more lasting results. (3)
Another treatment approach that might be potentially safer is epicutaneous immunotherapy (EPIT). This a treatment via a patch that delivers small doses of peanut allergen through the skin. The doses of allergen that are delivered via this method are much smaller and seem to be tolerated better in terms of allergic reactions. Some patients notice redness, itchiness or eczema-like reactions at the site of the patch. (4) Viaskin peanut patch therapy is currently in review for FDA license.
The studies in the last few years strongly suggest that early introduction of allergenic food groups leads to a decreased risk of developing a food allergy. For families with a history of food allergies, such as egg allergy or eczema early evaluation can be key. Currently, guidelines now recommend the introduction of peanut-containing foods as early as 4-6 months for infants with eczema or egg allergy.
Really interesting data is also coming out regarding gut microbiome (bacteria that lives in our GI tract) and food allergies. One group looked at the use of hydrolyzed formula with and without the use of probiotic Lactobacillus rhamnosus in infants with milk allergy. The study showed that milk allergy resolved faster in the treatment group. (5)
This is an exciting time for sure in the field of food allergy. Likely within the next year, we will have options for addressing peanut allergy that are more than just avoidance! Families with a history of food allergies and eczema might find it helpful to consult with an allergist in terms of risk stratification and review of treatment options.
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References:
- The PALISADE group. AR101 Oral Immunotherapy for Peanut Allergy. Nov 2018. NEJM; 379:1991-2001
- MacGinnitie et al. Omalizumab facilitates rapid oral desensitization for peanut allergy. JACI 2017; 139: 873-81, e8
- Vickery et al. Early oral immunotherapy in peanut-allergic preschool children is safe and highly effective. JACI 2017; 139:173-81, e8
- Sampson et al. Effect of varying doses of epicutaneous immunotherapy vs placebo on reaction to peanut protein exposure among patients with peanut sensitivity: a randomized clinical trial. JAMA 2017; 318:1798-809
- Berni et al. Extensively hydrolyzed casein formula containing Lactobacillus rhamnosus GG reduces the occurrence of other allergic manifestation in children with cow’s milk allergy: a 3-year randomized controlled trial. JACI 2017; 139: 1906-13, e4.
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