Safety and Efficacy of Flumatinib in Patients with Chronic Phase Chronic Myeloid Leukemia: A Real-Life Cohort Observational Study

Background: This study aims to comprehensively evaluate the safety and effectiveness of flumatinib in both first-line and subsequent-line therapies in 244 chronic-phase chronic myeloid leukemia (CML-CP) patients. Methods: Response criteria were applied according to the European LeukemiaNet. Adverse events (AEs) occurring after flumatinib treatment were documented and graded for severity. Results: The study encompassed 244 patients with CML-CP, stratified by treatment lines: first-line (1L, N=138), second-line (2L, N=63), and third-line or above (≥3L, N=43). First-line flumatinib therapy resulted in a major molecular response achieved by 50.7% at 6 months and 66.7% at 12 months, with a deep molecular response (DMR) achieved by 20.3% at 6 months and 35.5% at 12 months. In subsequent treatment lines, those with baseline MR2 had a DMR rate of 42.9%, compared to 23.3% for those without it. Significant differences in molecular response rates were observed based on treatment line and prior tyrosine kinase inhibitors (TKI) resistance (p<0.05). However, subgroup analyses showed no significant differences in treatment responses between the warning and resistance groups after flumatinib therapy. Dose reduction strategies, implemented in 19.3% of patients, have proven feasible without compromising efficacy. Eight patients subsequently attempted treatment cessation, with five maintaining treatment-free remission. AEs were predominantly grade 1-2, with diarrhea (27.0%), fatigue (12.3%), and thrombocytopenia (11.5%) being the most frequent. Grade 3/4 AEs were infrequent, highlighting flumatinib's manageable safety profile. Conclusion: Flumatinib displays significant clinical efficacy and a superior safety profile compared to other second-generation TKI, whether administered in first-line or subsequent treatment settings.