Follow-up Study on Chronic Myeloid Leukemia Patients Achieving Treatment-free Remission

1\. Primary goal: To evaluate the feasibility, safety and clinical consequences of TKI discontinuation in chronic phase CML(CP-CML) patients with deep treatment response and good medical compliance in Taiwan

2\. Molecular response monitoring:

1. After discontinuation of TKI therapy, participants will receive monthly molecular monitoring of BCR-ABL transcript levels by real-time quantitative polymerase chain reaction (RT-qPCR) for one year, every two months for the second year and every three months thereafter. 2. If loss of major molecular response (MMR) (BCR-ABL transcript level ⩽ 0.1% IS) is detected at any time point post TKI discontinuation, the participant should receive repeated testing within two weeks. If loss of MMR is confirmed, TKI should be resumed within four weeks 3. RT-qPCR of BCR-ABL would be ordered every four weeks until MR4 (BCR-ABL transcript level ⩽ 0.01% IS) is re-established, and then every 12 weeks indefinitely. 4. For patients who fails to achieve MMR again within three months after TKI is re-initiated, BCR-ABL kinase domain mutation testing would be performed

• The proportion of patients who were in MR4.5 (BCR-ABL transcript level ⩽0.0032% IS) and off treatment [Срок оценки: at week 48 of TKI discontinuation]
• Treatment-free survival [Срок оценки: From the start of TKI discontinuation until the earliest occurrence of any of the following: loss of MMR, restart of TKI for any reason, progression to accelerated phase/blast phase, or death of any cause, assessed up to 60 months]
• The proportion of patients who reachieved of MMR after TKI restart [Срок оценки: qPCR of BCR-ABL would be checked every four weeks until MR4 is re-established, and then every 12 weeks until study completion (week 240).]
• The proportion of patients who reachieved of MR4.5 after TKI restart [Срок оценки: qPCR of BCR-ABL would be checked every four weeks until MR4 is re-established, and then every 12 weeks until study completion (week 240).]
• Incidence and severity of treatment-related adverse events [Safety and Tolerability] [Срок оценки: Evaluation of AEs would be conducted on an ongoing basis on study until 30 days after the last day of TFR]