Real-World Evidence-Based Study on Treatment-Free Remission in Chronic Myeloid Leukemia.

BACKGROUND: Treatment-free remission (TFR) has become a treatment goal for chronic myeloid leukemia (CML). This study aimed to define precise conditions for treatment discontinuation and to develop TFR prediction models in a Chinese population. PATIENTS AND METHODS: This study collected data from 11 centers involving 802 cases of tyrosine kinase inhibitor (TKI) discontinuation in patients with CML. Eligible patients had received any TKI for at least 3 years and had maintained a deep molecular response (DMR) for at least 2 years. The primary endpoint was maintenance of major molecular response (MMR) within 12 months after discontinuation. RESULTS: Among 698 eligible patients (459 in the learning cohort and 239 in the validation cohort), 318 (45.6%) lost MMR, most commonly within the first 6 months after discontinuation (234/318; 73.6%). TFR rates were 66.5% at 6 months, 57.7% at 12 months, and 55.5% at 24 months. All patients regained MMR/DMR upon TKI reinitiation, with no disease progression. Longer treatment duration and sustained DMR were associated with higher TFR rates for both imatinib and second-generation TKIs. Superior outcomes correlated with low Sokal risk, no resistance, ≥5 years of TKI therapy, optimal DMR duration, and achievement of MMR at 12 months. The rate of sustained TFR was 73.5%, 60.0%, 44.6%, and 20.6% for patients with 0, 1, 2, and ≥3 nonoptimal factors, respectively. We developed predictive models and created a web-based calculator to assist clinicians in decision-making. CONCLUSIONS: Patients achieving durable DMR can safely discontinue therapy with rigorous monitoring. TFR attempts remain viable even under nonoptimal conditions, provided that adequate DMR duration and close monitoring are maintained.