A small number of patients on sublingual immunotherapy (SLIT) can achieve what researchers call “sustained unresponsiveness” – the ability to come off the treatment after desensitization has been achieved. A few weeks later, researchers challenge the patient with the allergen to see if their level of tolerance has stayed the same or if it has decreased.
In the study, presented at the American Academy of Allergy, Asthma and Immunology conference in Atlanta this weekend, 37 children aged 1 to 11 years old were put on peanut SLIT for three to five years. In SLIT, patients get a gradually increasing dose of peanut extract under the tongue.
At the end of their therapy, 86 percent of the kids were able to eat 300 milligrams of peanut (about one peanut) and 32 percent were able to eat 5,000 milligrams of peanut (about 16 to 20 peanuts).
It was these 12 patients who were able to tolerate the 16 to 20 peanuts who were then taken off the dose of immunotherapy, and challenged with same amount of peanuts two to four weeks later.
“What we found was that 10 of those 12 were still able to safely eat the 5,000 milligrams [of peanut], which ended up being about 27 percent of the total population of patients,” said Dr. Edwin Kim, an assistant professor of allergy and immunology at the University of North Carolina at Chapel Hill and an author of the study.
“We think that the extended amount of treatment continues to maintain this level of protection that we saw after one year,” Kim told a press conference on March 5. But he noted, “There still continues to be a pretty wide range of response to treatment. We have some patients who didn’t respond well, and then we had a big portion who actually ate the entire 5,000 milligrams or close to it.”
Oral immunotherapy, in which patients actually consume a small – then gradually increasing amount of peanut – has been shown to be more effective than SLIT. However, the method also is associated with more severe reactions.