Scientific Study

Background: Prior studies of peanut sublingual immunotherapy (SLIT) have suggested a potential advantage with younger age at treatment initiation. Objective: We studied the safety and efficacy of SLIT for peanut allergy in 1- to 4-year-old children. Methods: Peanut-allergic 1- to 4-year-old children were randomized to receive 4 mg peanut SLIT versus placebo. Desensitization was assessed by double-blind, placebo-controlled food challenge (DBPCFC) after 36 months of treatment. Participants desensitized to at least 443 mg peanut protein discontinued therapy for 3 months and then underwent DBPCFC to assess for remission. Biomarkers were measured at baseline and longitudinally during treatment. Results: Fifty participants (25 peanut SLIT, 25 placebo) with a median age of 2.4 years were enrolled across 2 sites. The primary end point of desensitization was met with actively treated versus placebo participants having a significantly greater median cumulative tolerated dose (4443 mg vs 143 mg), higher likelihood of passing the month 36 DBPCFC (60% vs 0), and higher likelihood of demonstrating remission (48% vs 0). The highest rate of desensitization and remission was seen in 1- to 2-year-olds, followed by 2- to 3-year-olds and 3- to 4-year-olds. Longitudinal changes in peanut skin prick testing, peanut-specific IgG4, and peanut-specific IgG4/IgE ratio were seen in peanut SLIT but not placebo participants. Oropharyngeal itching was more commonly reported by peanut SLIT than placebo participants. Skin, gastrointestinal, upper respiratory, lower respiratory, and multisystem adverse events were similar between treatment groups. Conclusion: Peanut SLIT safely induces desensitization and remission in 1- to 4-year-old children, with improved outcomes seen with younger age at initiation. Keywords: Peanut allergy; SLIT; desensitization; food allergy; food immunotherapy; remission; sublingual immunotherapy. https://doi.org/10.1016/j.jaci.2023.08.032