Treatment Option Overview for CEL

CEL is rare, and the optimal treatment remains uncertain. The clinical course can range from cases with decades of stable disease to cases with rapid progression to acute leukemia. Case reports suggest that treatment options include bone marrow transplant and interferon alfa.[3,4]

Treatment of HES has included corticosteroids, chemotherapeutic agents (e.g., hydroxyurea, cyclophosphamide, or vincristine), and interferon alfa.[5,6]

Case reports suggest that patients with HES who have not responded to conventional options may have symptomatic responses to imatinib mesylate.[6-8][Level of evidence C3] Imatinib mesylate acts as an inhibitor of a novel FIP1L1::PDGFRA fusion tyrosine kinase, which results as a consequence of an interstitial chromosomal deletion.[6,9][Level of evidence C3] HES with the FIP1L1::PDGFRA fusion tyrosine kinase translocation has been shown to respond to low-dose imatinib mesylate.[9]