Supplementary Material for: Effectiveness and Safety of Double-Blind, Placebo-Controlled, Low-Dose Oral Immunotherapy with Low Allergen Egg-Containing Cookies for Severe Hen’s Egg Allergy: A Single-Center Analysis

Introduction: The usefulness of low-dose oral immunotherapy (OIT) for the treatment of egg allergy has been unclear. Objective: To evaluate the efficacy and safety of OIT with low allergen cookies (LACs) containing a low dose of hen’s egg. Method: Thirty-three patients with severe hen’s egg allergy were randomly administered either OIT with LACs (n = 21) or placebo (n = 12). Two patients in the LACs group withdrew before completing OIT. The primary endpoint was the number of good responders (G-R), patients with negative results in the oral food challenge (OFC) with a final dose of 2 g hard-boiled egg whites after 4 months of OIT, in each group. Total OFC Aichi score for anaphylaxis/cumulative protein dose (TS/Pro) as the marker of severity of food allergy was also compared. Adverse events during OIT were evaluated using patients’ diaries. Results: The proportion of G-R in the LACs group was higher than in the placebo group (7/19 [37%] vs. 1/12 [8%], χ² test; p = 0.077). The TS/Pro after OIT in the LACs group was lower than in the placebo group (median score, 44.2 vs. 104.1, p = 0.059; Mann-Whitney U test). The threshold and TS/Pro before and after OIT significantly improved in the LACs group (p = 0.015, p = 0.027, respectively; Wilcoxon signed-rank test). There were 99 recorded incidences of symptoms of 1,938 intake events in the LACs group during OIT. Of these, 90 were mild; no severe symptoms occurred. Conclusions: OIT with LACs potentially increases the OFC threshold and decreases allergy severity and is a relatively safe treatment modality.