Treatment of Hypereosinophilic Syndrome Corticosteroids for hypereosinophilia and often for ongoing treatment of organ damage Imatinib for patients with the FIP1L1/PDGFRA - associated fusion gene or other similar gene fusions Sometimes drugs to control eosinophil counts (eg, hydroxyurea, interferon alfa, etoposide, cladribine) Supportive care Treatments include immediate therapy, definitive therapies (treatments directed at the disorder itself), and supportive therapies (1).