[Observational study of chronic myeloid leukemia Chinese patients who discontinued tyrosine kinase inhibitors in the real-world].

This study aimed to observe whether the treatment-free remission (TFR) of second-generation tyrosine kinase inhibitors (TKI) in chronic myeloid leukemia (CML) is better than imatinib (IM) . The clinical data of 274 CML patients who discontinued treatment and with complete clinical data were retrospectively studied from June 2013 to March 2021. Using both univariate and multivariate Cox proportional hazards regression models, risk factors influencing TFR outcomes after drug withdrawal in CML patients were assessed. A total of 274 patients were enrolled, 140 patients were women (51.1%) , with a median age of 48 (9-84) years at the time of TKI discontinuation. Prior to TKI discontinuation, 172 (62.8%) patients were treated with IM, and 102 (37.2%) had received second-generation TKI treatment, including 73 patients who had shifted from IM to a second-generation TKI and 29 patients who used second-generation TKI as the first-line treatment. The rationale for converting to a second-generation TKI are as follows: 37 patients aimed deep molecular response (DMR) to achieve TFR, seven patients changed due to IM intolerance, and 29 patients changed because of failure to achieve the optimal treatment response. The use of the last type of TKI included 96 patients (94.1%) with nilotinib, three patients (2.9%) with dasatinib, and two patients (2%) with flumatinib, including one patient who changed to IM due to second-generation TKI intolerance. No statistical differences were found in the median age at diagnosis and TKI discontinuation, sex, Sokal score, IFN treatment before TKI, median time of TKI treatment to achieve DMR, and the reasons for TKI discontinuation between the second TKI and IM (>0.05) .The median cumulative treatment time of TKI (71.5 months 88 months, <0.001) , the last TKI median treatment time (60 months 88 months, <0.001) , and the median duration of DMR (58 months 66 months, =0.002) were significantly shorter in the second-generation TKI compared with IM. In the median follow-up of 22 (6-118) months after TKI discontinuation, 88 patients (32.1%) had lost their MMR at a median of 6 (1-91) months; of the 53 patients (60.2%) who lost MMR within 6 months, the overall TFR rate was 67.9%, and the cumulative TFR rates at 12 and 24 months were 70.5% and 67.5%, respectively. Withdrawal syndrome occurred in 26 patients (9.5%) . For patients who restarted TKI treatment, 72 patients (83.7%) achieved DMR again at a median treatment of 4 (1 to 18) months. The univariate analysis showed that the TFR rate of patients treated with second-generation TKI was significantly higher than those who were treated with IM (77.5% 62.2%, =0.041) . A further subgroup analysis found that the TFR rate of the second-generation TKI patients was significantly higher than those treated with IM (80.8% 62.2%, =0.026) . No significant difference was found in the second-generation TKI used as the first line treatment compared with those who were treated with IM (69.0% 62.2%, =0.599) . The multivariate analysis results showed that second-generation TKI treatment was an independent prognostic factor affecting TFR in patients who discontinued TKI (=1.827, 95% 1.015-3.288, =0.044) . In the clinical setting, more CML patients rapidly achieved TFR using second-generation TKI than IM treatment.