First Real-World Effectiveness Analysis of Preschool Peanut Oral Immunotherapy.

BACKGROUND: We previously described safety of preschool peanut oral immunotherapy (P-OIT) in a real-world setting; 0.4% of patients experienced a severe reaction, and 4.1% received epinephrine, during build-up. OBJECTIVE: To determine the effectiveness of preschool P-OIT after 1 year of maintenance. METHODS: Preschoolers (9-70 months) with at least 1 objective reaction to peanut (during baseline oral food challenge (OFC) or P-OIT build-up) received a follow-up OFC to cumulative 4000 mg protein after 1 year on 300 mg peanut daily maintenance. Effectiveness of desensitization was defined as proportion of patients with a negative follow-up OFC. Symptoms and treatment at follow-up OFC were recorded. RESULTS: Of the 117 patients who successfully completed 1 year of P-OIT and subsequently underwent a cumulative 4000-mg follow-up OFC, 92 (78.6%) had a negative OFC and 115 (98.3%) tolerated a cumulative dose of greater than or equal to 1000 mg. For the 25 (21.4%) who reacted, their threshold increased by 3376 mg (95% CI, 2884-3868) from baseline to follow-up; 17 (14.5%) patients experienced grade 1 reactions, 7 (6.00%) grade 2, and 1 (0.85%) grade 3. Two patients (1.71%) received epinephrine associated with P-OIT, and 1 (0.85%) went to the emergency department. CONCLUSIONS: Our data demonstrate that real-world preschool P-OIT is effective after 1 year of maintenance for those who received a follow-up OFC. For those who reacted, their threshold increased sufficiently to protect against accidental exposures. P-OIT should be considered for preschoolers as an alternative to current recommendations to avoid peanut.