Peanut sublingual immunotherapy: an alternative approach to peanut-allergy treatment

Published online: September 4, 2019

For the ever-growing numbers of patients diagnosed with food allergy, there are still no approved treatments available to decrease the risk and help patients living with these allergies. Immunotherapy, involving exposure to small, prescribed amounts of the food allergen, has risen to the top of treatments in development with recent highly publicized studies of peanut oral immunotherapy (OIT) and peanut epicutaneous immunotherapy (EPIT). These treatments promise desensitization and thereby a level of protection against unintentional ingestions of peanut. However, neither OIT or EPIT are cures and their protective effects likely require long-term continued treatment. Treatment with OIT and EPIT varies across several key aspects including the peak level of desensitization, the logistics of taking the treatment, and the safety of the treatment itself. It is because of these key differences that there may not be a best treatment for all, but instead a personalized approach to find the best treatment for an individual patient. Sublingual immunotherapy (SLIT) for peanut allergy offers an additional option with its unique administration and its promising safety and efficacy.

In the current issue of The Journal of Allergy and Clinical Immunology (JACI), Kim, et al from the University of North Carolina School of Medicine present the results of their study investigating the long-term safety and efficacy of SLIT in peanut allergic children. Children with a history of an allergic reaction to peanut and a blood peanut IgE level >7 kU/L were treated with the liquid peanut SLIT medication at a dose of 2 mg (1/150 of a peanut). The dose was given under the tongue and held for 2 minutes and this treatment was repeated daily for 3 to 5 years. After the treatment course was completed, the children underwent a double-blind, placebo-controlled food challenge (DBPCFC) during which they ate increasing amounts of peanut flour to measure their reaction threshold. For children safely eating all 16 peanuts (5000 mg) without an allergic reaction, the treatment was stopped for 2-4 weeks. Another DBPCFC was then done to look for a lasting effect of the desensitization. At baseline and throughout the study, blood and skin tests were also done to track changes to the allergic immune system related to desensitization.

Of the 48 peanut-allergic children ages 1-11 years that entered the study, 37 finished the treatment and the food challenges. Of these 37 children, 32 were able to safely eat at least 750 mg of peanut during the DBPCFC providing protection that was at least 10-times more than a typical unintentional ingestion of peanut. Twelve (25%) of the children completed the entire 16 peanut DBPCFC without symptoms and 10 of these children again did not have symptoms after repeating the DBPCFC off of SLIT for 2-4 weeks. Further supporting these findings, peanut SLIT also showed a suppressive effect on peanut skin testing and peanut IgE, IgG4, and basophil testing in the blood. More than 95% of the daily SLIT doses were successfully taken and of the ~5% of doses that caused symptoms, the majority were from itching in the mouth that stopped without treatment.

In this small, single center study, peanut SLIT provided a clinically important level of protection to the majority of peanut-allergic children. The treatment was simple to do and appeared to be very safe during home dosing. With its balance of protective desensitization, ease of administration and dosing safety, peanut SLIT may represent a viable alternative for patients when considering the ideal food allergy treatment for themselves.

The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.

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