A case of protracted eosinopenia after a single subcutaneous dose of benralizumab

ABSTRACT

Benralizumab is a humanized, afucosylated IgG1k monoclonal antibody directed against the α subunit of IL-5R. It inhibits IL-5, the main regulator of the biology of eosinophils, from binding to its specific receptor. Moreover, it directly targets and depletes eosinophils and other IL-5R + cells by inducing antibody-dependent cell-mediated cytotoxicity, differentiating it from the other IL-5 ligand targeted therapies. We report a case of a 61-year-old woman with severe eosinophilic asthma and rhinosinusitis, referred to our department in 2014. Blood eosinophilia (560 cells/μL) and normal total IgE levels (57 kU/L) were present. She was on GINA step-5 treatment with additional aminophylline 225mg twice daily. Control was not achieved despite good compliance with frequent asthma exacerbations requiring emergency department visits, multiple systemic corticosteroid courses and hospitalizations. Maintenance therapy with prednisolone 5mg daily was attempted with only a slight improvement. Although no more hospitalizations were required, she continued to have several asthma exacerbations. Treatment with subcutaneous Benralizumab 30mg was started in October 2020. The subsequent administration was skipped because the patient had COVID-19. An interval of approximately 3 months (82 days) separated the first 2 administrations. Regardless of our recommendation, the patient decided to discontinue systemic corticosteroids and aminophiline. Evaluation before the 2nd administration showed that blood eosinophils decreased to 0 cells/μL and clinical improvement that was established by disease control and health-related quality of life questionnaires (see table I) Although maintained eosinopenia after an isolated intravenous administration of Benralizumab has been reported, to our knowledge this is the first case related to a single subcutaneous administration in a previously eosinophilic patient. Additionally, clinical improvement was sustained in spite of stepping down her maintenance therapy. This case raises questions regarding the possibility and success of patient-oriented scheduling of Benralizumab administration as an alternative to the current treatment regimen. (Table Presented).