The purpose of this study is to explore the efficacy and safety of flumatinib in chronic phase of chronic myeloid leukemia (CML-CP) patients With Ph+ post imatinib failure.

A multicenter, single-arm, prospective, open-label study to detect the efficacy and safety of flumatinib by measuring rates of major molecular response (MMR) at 12 months in CML-CP patients with Ph+ in China. Approximately 200 Patients will be recruited consecutively from the study sites during the enrollment period and will be given flumatinib 600 mg QD. The duration of patient participation will be 24 months.

Inclusion Criteria:

• Age ≥ 18 years.
• Diagnosis of CML-CP with Ph+.
• ECOG performance of 0-2.
• Adequate end organ function defined as the following: total bilirubin <1.5x ULN, SGPT <2.5x ULN, creatinine <1.5x ULN.
• Treatment failure after imatinib at 3 or 6 months with BCR-ABL >10%.
• Patients must sign an informed consent form (ICF) indicating they are aware of the investigational nature of this study, in keeping with the policies of the hospital.

Exclusion Criteria:

• Previously documented T315I mutation.
• History of TKI treatments except of imatinib.
• History of undergone major surgery within 4 weeks.
• Patients unwilling or unable to comply with the protocol.
• Pregnant or breast-feeding patients.
• patients with other malignant tumor.