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:~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.~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~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.~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
In recent years, the goal of stopping drug therapy, also known as treatment-free remission (TFR), is emerging as one of the management goals of chronic myeloid leukemia (CML) therapy. Because there is no available data on Asian patients with CML undergoing tyrosine kinase inhibitor discontinuation (TKI), the investigators plan to recruit chronic phase CML patients with deep treatment response and good medical compliance in Taiwan to evaluate the feasibility, safety and clinical consequences of TKI discontinuation.