Anti-IL5R and anti-IL4Rα strategy in patients with severe allergic asthma: clinical observations

With the narrow action of immunobiological drugs, it is necessary to understand the pathogenetic mechanisms of severe asthma (SA) in a particular patient. The aim of the work was to demonstrate the importance of determining the endotype and phenotype of SA to select a targeted drug using the example of cases of anti-IL5R treatment failure in patients with allergic SA (ASA). Patients (n = 2) with ASA onset in childhood, identified causative allergens, and high eosinophilia before the start of targeted therapy are presented. The use of the anti-IL5 drug benralizumab in such cases is permitted by the Guidelines for Biological Therapy (The European Academy of Allergy and Clinical Immunology – EAACI, 2020), but the therapy was ineffective. The patients were switched to the anti-IL4R drug dupilumab, which indirectly blocks IgE production, with a positive outcome. Conclusion. The considered cases of ASA demonstrate the necessity of determining the endotype and phenotype of SA to select the targeted drug. The inefficiency of the anti-IL5R drug in patients with ASA is shown, despite the pronounced initial blood eosinophilia. In case of Th2-mediated eosinophilia in ASA, preference should be given to anti-IgE or anti-IL4R drugs.