Sublingual immunotherapy involves gradually desensitizing the immune system by administering small amounts of the allergen under the tongue. The purpose of the studies on SLIT for peanut allergies in toddlers was to see if this method could help reduce allergic reactions and improve tolerance to peanuts.
A three-year clinical trial funded by the National Institutes of Health and Food Allergy Research and Education (FARE) found that sublingual immunotherapy, or SLIT, is safe in peanut-allergic children aged one to four, with a higher likelihood of desensitization and remission the earlier treatment began.
Led by Edwin Kim, MD, associate professor of pediatrics at the UNC School of Medicine, this is the first randomized, controlled trial to investigate – in this young age group – the efficacy and feasibility of SLIT, which involves a tiny bit of peanut protein absorbed under the tongue.
The study, published in the Journal of Allergy and Clinical Immunology, included 1 to 4-year-old peanut-allergic children who were randomly assigned to receive 4 mg peanut SLIT or placebo. A total of 50 people were enrolled in the study (40 at UNC Medical Center and 10 at the University of Texas Southwestern Medical Center). Participants were randomly assigned to one of two groups: 25 received peanut SLIT and 25 received a placebo. It’s a method in which the treatment is administered as a small amount of liquid under the tongue, rather than as peanut flour mixed with other food and then eaten as in oral immunotherapy, or OIT. After three years of treatment, peanut desensitization was evaluated using a double-blind, placebo-controlled food challenge (DBPCFC).
Peanut OIT is currently available and being offered by increasing numbers of allergists, however we are quickly learning that in addition to its known risk of allergic reactions, the actual doing of OIT can be very difficult for many families.
Edwin Kim
The results showed that peanut SLIT is highly effective in treating peanut-allergic toddlers, with nearly 80% tolerating 15 peanuts without allergic symptoms after treatment. Because most typical peanut-allergic reactions are caused by one peanut or less, these findings would translate into strong protection against peanut exposure. Furthermore, researchers demonstrated that peanut allergy remission may be possible following peanut SLIT, with 63% of the toddlers maintaining their protection three months after stopping the treatment. These new findings indicate that peanut SLIT early intervention is promising and warrants further research.
“From our prior studies in older children, we were optimistic that peanut SLIT could have a similar treatment effect in toddlers,” said Kim, corresponding author of the study, pediatric allergy and immunology division chief and director of the UNC Food Allergy Initiative. “However, what we found was even better. The desensitization levels we saw were higher than expected and on par with levels we normally would only expect with oral immunotherapy. Just as important, rather than wearing off quickly, we were excited to see that over 60% stayed protected three months after stopping the treatment.”
One of the presumed advantages of the SLIT approach over OIT has been its overall safety and ease of administration. While the majority of OIT treatment side effects are mild to moderate, severe reactions requiring emergency treatment do occur, and there is an urgent need to develop treatments with more manageable side effects.
“Peanut OIT is currently available and being offered by increasing numbers of allergists, however, we are quickly learning that in addition to its known risk of allergic reactions, the actual doing of OIT can be very difficult for many families,” says Kim. “Peanut SLIT could be a good option to consider as it may be able to provide comparable levels of protection while being safe and easier to administer.”
According to Kim, the SLIT approach is likely to be a safer option than OIT, with the most common side effect being oral itching. Treatments that can protect children from allergic reactions while remaining safe and convenient for busy families can be life-changing, and researchers are hopeful that peanut SLIT will be one of them.
“Even with the push to introduce peanut in early childhood in order to prevent the allergy, peanut allergy remains one of the most common food allergies,” Kim said. “A result of early peanut introduction is that we are diagnosing peanut allergy at younger and younger ages making it vitally important to develop treatments that can be safe and effective at preventing allergic reactions in these young children.”
