Background: In Europe, Omalizumab (anti-IgE) is indicated for the treatment of moderate/severe asthma, but not for IgE-mediated food allergy (FA). Objective: We prospectively assessed the impact of Omalizumab for efficacy, safety, and quality of life (FA-QoL) in patients with moderate/severe asthma and history of anaphylaxis to peanut, tree nuts, fish, egg, milk, and/or wheat. Methods: Food-allergic children (6-18yrs) with moderate/severe asthma underwent oral food challenges (OFCs) to establish the threshold of reaction to the culprit food(s) at baseline (T0) and at four-month intervals (T1, T2, T3) during their first year of treatment with Omalizumab. We recorded the number and severity of food-allergic reactions, Asthma Control Test (ACT), FA-QoL, and total IgE. Results: In 65 patients allergic to 107 foods, the No Observed Adverse Events Level (NOAEL) at T1 increased: 243- and 488-fold for raw and baked milk, respectively; 172 and 134-fold for raw and baked egg; 245-fold for hazelnut; 55-fold for peanut; 31-fold for wheat, and 10-fold for fish. Full tolerance was achieved in 66.4% of OFCs at T1, 58.3% at T2, and 75% at T3. Ninety-five foods were liberalized ad libitum in the diet of 55 patients; the remaining 12 were introduced by 10 patients at least in traces. Throughout the study, 40/65 children got a free diet. ACT increased from 17 (Q1-Q3:15-17) to 23.6 (Q1-Q3:23-25). The FA-QoL score in children ≤ 12 years decreased from 4.63±0.74 to 2.02±1.13, in adolescents from 4.68±0.92 to 1.90±1.50. Conclusions: Omalizumab allows safe reintroduction of allergenic foods. Trial registration number: ClinicalTrials.gov, NCT06316414
