Abstract： Objective:To investigate the efficacy and safety of flumatinib in the treatment of imatinib-resistant or imatinib-intolerant patients with chronic phase chronic myelogenous leukemia (CML-CP).Methods:The clinical data of 9 CML-CP patients who received flumatinib after imatinib resistance or intolerance in Jining No. 1 People's Hospital from April 2020 to May 2021 were retrospectively analyzed. Patients were evaluated for the hematologic, cytogenetic and molecular responses, progression-free survival (PFS), event-free survival (EFS), and adverse reactions.Results:Among 9 CML-CP patients, there were 4 imatinib-resistant patients and 5 imatinib-intolerant patients. The median duration of flumatinib exposure was 17 months (1-25 months). Except for 1 case who discontinued flumatinib early due to grade 4 thrombocytopenia and other adverse reactions, 7 of the remaining 8 cases achieved the best response at 3, 6 and 12 months of flumatinib therapy. By the end of follow-up in April 2022, 7, 7 and 6 patients achieved complete cytogenetic response (CCyR), major molecular response (MMR) and molecular response 4.5 (MR4.5), respectively. The median time to achieving CCyR, MMR and MR4.5 was 4.5 months (3-6 months), 12 months (3-12 months) and 15 months (3-21 months), respectively. Within 17 months (11-25 months) of follow-up, 7 of the 9 patients had EFS and 8 patients with continuous flumatinib had PFS. Among 9 patients treated with flumatinib, hematologic adverse reactions were observed in 6 cases, and grade 3-4 hematologic adverse reactions occurred in 2 cases. Non-hematologic reactions events mainly included diarrhea (4 cases), muscle ache (2 cases), fatigue (2 cases) and liver damage (2 cases), which were all grade 1-2.Conclusions:Flumatinib is effective and well tolerated in the treatment of imatinib-resistant or imatinib-intolerant CML-CP patients.