Oral immunotherapy and omalizumab for food allergy Lefèvre S 1, 2, Kanny G 2,3 1 Allergy department, Metz-Thionville Hospital, Metz, France 2 EA « Innovative practices in health», University of Lorraine. Laboratory of medical Hydrology and Climatology, Faculty of medicine, Vandoeuvre-les-Nancy, France 3 Internal Medicine, Clinical Immunology and Allergology, University Hospital, Nancy, France Introduction The treatment of food allergy is based on food immunotherapy. The implementation of these treatments may be difficult if the food threshold’s patients are very low. Omalizumab (Novartis, Switzerland), a humanized anti-IgE antibody has been proposed as adjunctive therapy in severe food allergies. The anti-IgE pre-treatment can increase the reactivity thresholds and enable food desensitization. Results (2) Size of prick-tests: Peanut IgE rates: Peanut IgG4 rates: Cow’s milk Casein IgE rates: Cow’s milk Casein IgG4 rates RESULTS (3) ⍺-lactalbumin IgE rates: ⍺- lactalbumin IgG4 rates: Method We report 8 observations of successful food immunotherapy with omalizumab as adjunctive therapy in children (age 11.6 ± 3.3 y.o.) highly allergic (5 to milk, 2 to peanut, 1 to fish), for who neither a sublingual immunotherapy nor oral immunotherapy were initially unsuccessful. The clinical reactions presented by these patients are asthma for 7 patients and mild anaphylaxis reaction for 1 patient. The rates of IgE or IgG4, directed against peanut or cow’s milk, are not useful to follow an acquisition of tolerance. The size of skin prick tests decreases in 3-5 month after the beginning of treatment. Conclusions This study shows the possibility of inducing oral tolerance with omalizumab for highly allergic patients with a very low threshold reactivity and at risk of severe anaphylactic reactions. The acquisition, even partial, of oral tolerance puts these patients away to the risk of anaphylaxis by accidental ingestion. The size of skin prick tests decreases in 3-5 month after the beginning of treatment. There is no biological marker indicating the occurrence of tolerance. RESULTS (1) The pre-treatment with omalizumab for 3 to 5 months allowed all patients to increase them threshold’s reactivity: 100 fold for peanuts, 875 for fish, and 4.5 for cow's milk. It allowed an immunotherapy leading to a current consumption of the culprit food for 5 patients and consumption of more than 6 ml of milk for 3 children. Characteristics of patients: Allergens Initial cumulative dose reactogenic (mg) Dosage of omalizumab Tolerated dose Duration of treatment (month) Acquired tolerance Peanut 65 225 mg/15d 10 g to 7 month 17 4 peanuts, 2 or 3 by week 44 375 mg/15d 10 g to 5 month 19 8 peanuts, 2 or 3 by week Fish 8 300 mg/15d 7 g to 3 month 6 Daily consumption Cow's milk 5 300 mg/month 10 ml to 2 month 21 < 0,05 6,8 ml to 4 month 29 20 ml/d, 2 yogurt, grated cheese 3 150 mg/15d 23 ml to 16 month 200 ml/d 4 225 mg/month 3 ml to 3 month > 24 In progress, 13 ml/d 0,3 ml to 3 month > 30 In progress, 6 ml/d CONTACT INFORMATION Sebastien LEFEVRE, M.D. CHR Metz-Thionville – Unité d’Allergologie 1 allée du château, 57085 Metz, France + 33 3 87 55 33 83 s.lefevre@chr-metz-thionville.fr