Objectives: To evaluate the efficacy and safety of imatinib mesylate (imatinib) for myeloproliferative neoplasm (MPN) patients with eosinophilia.
Methods: Eight MPN patients with eosinophilia and positive FIP1L1-PDGFR alpha gene and one CEL, NOS were treated with 100 mg or 400 mg/d imatinib orally.
Results: Hematological remission (HR) rate was 100%, including complete HR (CHR) rate 87.5%, and partial remission (PR) rate 12.5% with a median follow-up of 16 (6.0 -26.0 ) months. Complete molecular remission (cMR) rate was 85.7%. The median time of FIP1L1-PDGFR alpha fusion gene becoming negative was 4 (1.5 - 8) months. Three patients withdrew imatinib after getting cMR. After a median follow-up of 12 months, all the 3 patients remained in CHR. The main adverse effect of imatinib was mild myelosuppression occurring in 37.5% of patients in a median time of 6 (4 - 9) days after treatment.
Conclusion: Imatinib in treatment of MPN with eosinophilia and positive FIP1L1-PDGFR alpha gene patients can induce high hematologic and molecular remission. The adverse effects of imatinib are mild and tolerable.