Omalizumab effectiveness in patients with a previously failed oral immunotherapy for severe milk allergy

Background: Some studies addressed the issue of omalizumab (OML) effectiveness in children starting their first oral immunotherapy (OIT) attempt but no study investigated the possible role of OML in the setting of patients with persisting milk allergy after a failed OIT attempt. Methods: Single-center, prospective, observational study in a selected group of patients with a persisting and severe cow milk (CM) allergy associated with moderate allergic asthma, in which a previous OIT attempt had already failed. We performed an open oral food challenge (OFC) to identify patients who tolerated less than 173 mg of cow's milk protein. At the end of the recruitment, we have found four patients with a mean age of 16.25 years (8-24) who had suspended a previous OIT attempt and still reacted to an amount of CM equal or below 173 mg. Enrolled patients, after an 8-week course of OML along with a CM avoiding diet, underwent again an open OFC with CM to re-evaluate their threshold. Eventually, a new OIT course was started using the same OIT protocol of the previous attempt, maintaining cotreatment with OML for the first 12 months. For each patient, we documented: the threshold of CM at OFC, level of specific immunoglobulin E (IgE) and IgG4 for milk, and quality of life (QoL). Results: During OIT the four patients experienced no reactions or extremely mild ones (oral itching, transient mild abdominal pain). All increased their threshold of CM in OML if compared with the baseline and maintained it long after that biologic therapy had discontinued. Specific milk proteins IgG4 levels significantly increased in all. Conclusion: In this series, OML was effective in patients with severe CM allergy who had previously failed OIT, allowing milk intake without adverse reactions and improving the QoL.