Efficacy of Flumatinib in CML Patients with F359V/C Mutation

The BCR-ABL mutation is the main cause of tyrosine kinase inhibitors(TKI) resistance. The second-generation TKI can overcome most of the mutations. However, both dasatinib and nilotinib have a unique set of mutants with reduced sensitivity. All TKIs are associated with adverse events, which lead to treatment discontinuation and affect the quality of life of patients. Flumatinib showed higher activity against BCR-ABL mutants in vitro. Drug-related adverse events of flumatinib were mainly grade 1 or grade 2 events. There is no study that reported the efficacy of flumatinib against F359V/C mutation.We report two cases of chronic myelocytic leukemia(CML) patients with F359V/C mutation resistance to Imatinib therapy. One patient with F359V mutation was shifted to Dasatinib. Repeated massive pleural effusion and anemia occurred after Dasatinib treatment, forcing drug dosage reduction or withdrawal, affecting drug efficacy and quality of life of patient. Two patients were shifted to Flumatinib. MR4 was achieved and F359V/C mutation was not detected after treatment with Flumatinib. There was no significant side effect. The patients had a high quality of life. Flumatinib is effective against F359V/C mutation, has less drugrelated adverse reactions. Flumatinib may be a better choice for patients with F359V/C mutation.

Supplementary information: The online version contains supplementary material available at 10.1007/s12288-022-01585-3.