Open-Label Study of the Efficacy, Safety, and Durability of Peanut Sublingual Immunotherapy in Peanut-Allergic Children

To evaluate sublingual immunotherapy (SLIT) as a treatment of children with peanut allergy.Forty-seven children 1 to 11 years of age (mean 7.1 year) with peanut allergy confirmed by a history of reaction to peanut, positive peanut specific IgE test, and double-blind placebo-controlled food challenge (DBPCFC). SLIT was administered once daily by a pump dispensing peanut protein in a liquid form held under the tongue beginning at 2.5 mcg and progressing through 14 dose escalations every 1 or 2 weeks to a maintenance dose of 4 mg. After 4 years, patients underwent another double-blind placebo-controlled food challenge. Thirty-seven children subsequently underwent an avoidance phase to assess for loss of any achieved desensitization.The mean successfully consumed dose (SCD) increased from 48 mg to 2723 mg of peanut protein after SLIT (P < .0001), with 70% achieving SCD > 800 mg and 36% achieving SCD = 5000 mg. For reference, 1 peanut kernel contains about 300 mg of peanut protein. Median rate of reaction per dose was 0.5%, mostly transient oropharyngeal itching. There were no dosing symptoms requiring epinephrine. During the avoidance phase, desensitization tended to be lost over time.“Peanut SLIT was safe and induced clinically significant desensitization in most children.”Other studies of immunotherapy for peanut allergy in children have used swallowed peanut protein (termed oral immunotherapy [OIT]) on an escalating schedule up to higher maintenance doses of as much as 300 mg and have been complicated by higher rates of adverse reactions. The maintenance dose of only 4 mg in the present study using SLIT likely explains a lower rate of adverse reactions compared with OIT, but SLIT, nonetheless, resulted in substantial desensitization. OIT has proven more successful when started in infancy or toddlerhood, and thus it is encouraging that in the present study of older children, SLIT has demonstrated effectiveness. Although the goal of peanut immunotherapy is sometimes described as being able to prevent anaphylaxis to accidental exposures to small amounts, for example less than 300 mg, severe reactions to such small amounts are actually quite rare. A more meaningful goal would be to allow the ingestion of the food in normal amounts. SLIT in this study allowed 36% of the children to ingest 5000 mg (approximately 17 peanut kernels) and perhaps higher amounts without reaction. It has also become clear that with any form of peanut immunotherapy (OIT or SLIT), maintaining desensitization requires ongoing exposure. All infants should have peanut and other potentially allergenic food proteins incorporated into their diets in any form that does not present a choking hazard at 4 to 6 months of age as other complementary foods are introduced because it dramatically decreases the likelihood of becoming allergic to these foods. If children become allergic, despite this early introduction, they should immediately be offered some form of food immunotherapy in an attempt to build tolerance, with the goal of allowing them to eventually eat the food normally, and perhaps even leading to resolution of the food allergy.