Introduction: An increase in blood eosinophil count (BEC) is a common side effect observed during the first months of anti-IL4/13 dupilumab treatment. The accumulation of blood eosinophils is likely caused by inhibition of eosinophil migration to peripheral tissues due to downregulation of adhesion molecules and continued eosinophilopoiesis in the bone marrow. We sought to review events of hyperosinophilia (BEC >1500/μL) in CRSwNP patients treated with dupilumab in our clinic.
Methods: We started 36 patients on dupilumab between 04/21 and 10/23. Blood eosinophil counts were monitored before and 4 weeks after initiation of dupilumab. If there was no or only a moderate increase in BEC, patients were re-evaluated after 3 months; if BEC exceeded >1500/µL, patients were re-evaluated after 2 weeks.
Results: Of the patients analysed, 8% (3/36) had BECs >1500/µl between 4 and 12 weeks after starting dupilumab. While one patient with 5,091 Eos/µl (long-term medication with prednisolone 7.5mg) showed no symptoms, another patient with 2,320 Eos/µl (no concomitant medication) complained of arthralgia and fatigue, and one patient with 22,172 Eos/µl (who had stopped her oral corticosteroids with the start of dupilumab) suffered a lacunar stroke. Dupilumab therapy was discontinued in the symptomatic patients and all 3 patients were started on cocorticosteroids.
Conclusion: Hypereosinophilia tends to be a transient and asymptomatic side effect of dupilumab treatment in the majority of cases. However, in rare cases, significant organ damage is possible. Therefore, BECs should be closely monitored during the first months of dupilumab treatment.
R. Böscke erhielt Vortragshonorare und Reisekostenerstattung von Sanofi, Novartis und GSK. Die übrigen Autoren geben an, dass kein Interessenkonflikt besteht.