Treatment-Free Remission After Tyrosine Kinase Inhibitor Discontinuation in Chronic Myeloid Leukemia: A Single-Center Real-World Retrospective Study

Abstract

Background. Treatment-free remission (TFR) has emerged as a therapeutic goal for patients with chronic myeloid leukemia (CML) who achieve deep molecular response (DMR) during tyrosine kinase inhibitor (TKI) therapy. However, real-world evidence from Chinese cohorts remains limited, and published data on TFR following discontinuation of flumatinib—a domestically developed second-generation TKI—are virtually absent.

Objective. To evaluate TFR outcomes and identify prognostic factors associated with molecular recurrence in a real-world cohort of CML patients who discontinued TKI therapy.

Methods. This retrospective single-center study analyzed 49 chronic-phase CML patients who discontinued TKIs between January 2014 and May 2026. TFR was defined as the maintenance of major molecular response (MMR; BCR::ABL1 ≤0.1% on the International Scale) after TKI discontinuation; molecular recurrence was defined as confirmed loss of MMR. Comparisons between recurrent and non-recurrent groups were performed using standard statistical tests, and TFR duration was estimated by the Kaplan–Meier method.

Results. The cohort comprised 49 patients (55.1% female; mean age 59.1 years, range 20–83) treated with imatinib (n=21), nilotinib (n=16), flumatinib (n=11), or dasatinib (n=1). Median TKI treatment duration was 89.0 months (mean 99.2 ± 53.8). The overall TFR success rate was 79.6% (39/49), with a median TFR duration of 16.5 months (range 1–144). Molecular recurrence occurred in 10 patients (20.4%), and 8 of 10 relapses occurred within the first 6 months. The non-recurrent group had substantially longer mean treatment duration than the recurrent group (110.8 vs. 53.8 months). By TKI type, TFR success rates were 100% for nilotinib (0/16 recurrence), 76.2% for imatinib (5/21), and 63.6% for flumatinib (4/11). All recurrent patients regained MMR upon TKI reinitiation.

Conclusion. TFR is achievable in approximately 80% of carefully selected real-world CML patients. Longer cumulative TKI treatment duration is strongly associated with successful TFR outcomes. A cautious approach to flumatinib discontinuation is warranted until prospective data become available.