The purpose of this study is to explore the efficacy and safety of switching to flumatinib versus dasatinib after imatinib-related low-grade adverse events in patients with chronic myeloid leukemia in chronic phase (CML-CP) in China. This is a post-marketing, interventional, double-arm, prospective, open-label, randomized controlled study in CML-CP patients in China. Patients will be recruited consecutively from the study sites during the enrollment period. The enrolled patients will be given flumatinib or dasatinib under the conditions of informed consent and frequent monitoring according to the clinical guideline.

Inclusion Criteria:

• Age ≥ 18 years;
• Diagnosis of CML-CP with Ph+;
• ECOG 0, 1, or 2;
• Patients with imatinib-related Low-grade Adverse Events for more than 12 months and AE lasting for at least 2 months, or relapsed at least 3 times in the past 12 months;
• Ability to provide written informed consent prior to any study related screening procedures being done

Exclusion Criteria:

• Previously documented T315I mutation;
• Previous treatment with any other tyrosine kinase inhibitor except for imatinib;
• Prior accelerated phase or blast phase CML;
• Loss of CHR or cytogenetic response