Postmarketing Analysis of Eosinophilic Adverse Reactions in the use of Biologic Therapies for Type 2 Inflammatory Conditions

BackgroundTemporary eosinophilia is a potential adverse reaction of monoclonal antibody therapies in the treatment of a variety of type 2 inflammatory conditions, including asthma and chronic rhinosinusitis with nasal polyposis (CRSwNP). The pathophysiology, epidemiology, and clinical significance of eosinophilia and eosinophilic adverse reactions following the initiation of biologic therapy are unclear.ObjectivesTo describe the postmarketing, eosinophilic adverse reactions with clinical significance in patients treated with the 3 biologic therapies approved by the U.S. Food and Drug Administration (FDA) for CRSwNP: dupilumab, omalizumab, and mepolizumab.MethodsThe FDA Adverse Event Reporting System (FAERS) Public Dashboard was searched for eosinophilic adverse reactions related to dupilumab, omalizumab, and mepolizumab treatments from November 2004 to December 2022. Data regarding each of the eosinophilic adverse reactions were extracted and analyzed.ResultsA total of 218, 270, and 134 reports of eosinophilic adverse reactions were reported among patients who were treated with dupilumab, omalizumab, and mepolizumab, respectively. The most common eosinophilic adverse reaction was eosinophilic granulomatosis with polyangiitis (338 patients), followed by eosinophilic respiratory tract reactions (158 patients). The most common indication for biological treatment among the reaction groups was asthma.ConclusionsEosinophilic adverse reactions are rare but consequential complications of biological treatment. They are more common among patients treated for asthma and chronic rhinosinusitis with nasal polyposis. Measuring and monitoring blood eosinophil levels may be appropriate in specific clinical instances when patients are started on different biologic therapies for type 2 inflammatory conditions.