Oral immunotherapy in severe cow's milk allergic patients treated with omalizumab: Real life survey from a Spanish registry.

BACKGROUND: Oral immunotherapy is a frequent treatment for the management of food allergies, but adverse events (AE) are common. This study assessed the outcome of cow's milk oral immunotherapy (MOIT) in severe cow`s milk-allergic patients treated with omalizumab in a real-life setting. METHODS: OmaBASE was a national, multicenter, open, and observational registry that collected clinical, immunologic, and treatment from patients with food allergy receiving omalizumab. RESULTS: Data derived from 58 patients aged 10.3 years (IQR 6.3-13.2) and median milk-specific IgE 100 kUA /L at the start of omalizumab treatment. Most had experienced anaphylaxis by accidental exposures (70.7%) and had asthma (81.0%). Omalizumab in monotherapy induced tolerance to ≥6000 mg of cow's milk protein (CMP) to 34.8% of patients tested by oral food challenge. Omalizumab combined with MOIT conferred desensitization to ≥6000 mg of CMP to 83.0% of patients. Omalizumab withdrawal triggered more AE (P = .013) and anaphylaxis (P = .001) than no discontinuation. Anaphylaxis was observed in 36.4% of patients who discontinued omalizumab, and more in those with sudden (50.0%) rather than progressive (12.5%) discontinuation. At database closure, 40.5% of patients who had completed follow-up tolerated CMP without omalizumab (7.2% 1500-4500 mg; 33.3% ≥6000 mg). CONCLUSION: Milk oral immunotherapy initiated under omalizumab allows the desensitization of subjects with severe cow's milk allergy even after omalizumab discontinuation. However, discontinuation of omalizumab can lead to severe AE and should be carefully monitored.