In a case series including four patients previously treated with an anti-IL-5 or anti-IL-5R biologic for OCS-dependent asthma, Eger et al. [93] showed that the switch to this anti-IL-4/IL-13 biologic, together with discontinued OCS use, may induce hypereosinophilia, with sudden deterioration of asthma, tissue infiltration by eosinophils, and EGPA-like symptoms, such as thromboembolic events. The gene discussed is IL5RA; the disease is asthma.