An enhanced dosage of a unique type of peanut allergy immunotherapy, led by Edwin Kim, MD, at the UNC School of Medicine, is continuing to show promise for children.
Sublingual immunotherapy, or SLIT, provides durable desensitization to peanuts in peanut-allergic children following a four-year phase 2 trial. A tiny amount of peanut protein is used in SLIT, equivalent to only 1/75th of a peanut kernel. Unlike Palforzia peanut oral immunotherapy, which requires patients to eat medical grade peanut flour every day, it is absorbed under the tongue.
Published in the Journal of Allergy and Clinical Immunology, corresponding author Kim, associate professor of pediatrics at UNC School of Medicine, has shown that 4 mg of peanut SLIT can provide strong desensitization in most children to protect them against accidental peanut exposure . Furthermore, the clinical study supports the safety of the treatment.
As a father of two kids who have suffered anaphylaxis to nuts, Kim knows what it can be like for parents and children with food allergies. Children need a treatment that protects them from the unforeseen, but it needs to be safe and simple, he says. It shouldn’t add to the stress and worry families already face daily.
Their 2011 placebo-controlled study showed that peanut SLIT could desensitize, defined as increasing the amount of peanut needed to cause an allergic reaction . The treatment has proven safe, and a small group of patients could stop treatment for a month and still be desensitized after 5 years.
The current trial aims to answer two key questions from the first study: could higher doses be more effective and how long will the treatment last. To begin with, peanut SLIT doses were raised from 2mg to 4mg. Second, in a first-of-its-kind approach, patients completing peanut SLIT who had been desensitized and expected to be protected against incidental exposures of peanut were then removed from treatment for anywhere from 1 to 17 weeks to test how long the immunity would last.
Of the 54 peanut-allergic children participating in the study, 47 completed the treatment with 70% showing protection against accidental exposures of peanut (>800 mg peanut, ~3 peanuts) and 36% showing full desensitization (5,000 mg of peanut, ~16 peanuts). Based on the results of the study, the average threshold after treatment was 2,723 mg, compared to 1,700 mg using the 2 mg dose in the pilot study.
Despite the higher dose, safety was close to the pilot study, with only 4% of doses resulting in side effects, most of which were itchiness in the mouth. There were no side effects that called for treatment with epinephrine (EpiPen).
According to Kim, even with the most careful precautions, cross-contamination and accidental ingestions can happen, and allergic reactions can occur. The results from this study indicate that SLIT is effective in desensitizing the majority of peanut-allergic children, which should protect them from these unexpected circumstances.
A model of the time off peanut SLIT showed that on average, it would take 22 weeks for the patient to become re-sensitized to small amounts. Occasionally, life happens and treatments may be missed, Kim said.
It could be due to a vacation, sickness or just forgetting. According to this exciting new study, peanut SLIT’s effects on the immune system may not be permanent, but they are long-lasting.
Kim points out that this not only provides reassurance in cases of missed doses, but it may also suggest future dosing strategies. Although sublingual immunotherapy isn’t a cure, it could potentially help a lot of peanut-allergic patients and their families by protecting against allergic reactions while still being easy and safe to administer, he explained .