[Analysis on tyrosine kinase inhibitor discontinuation in patients with chronic myeloid leukemia in the real world: experience from single center].

Objective: To explore status of tyrosine kinase inhibitor (TKI) discontinuation in patients with chronic myeloid leukemia (CML) in the chronic phase (CP) in the real world, to analyze causes, factors and outcomes associated with TKI discontinuation and the possibility of pursuit treatment-free remission (TFR) in China. Methods: From January 2013 to August 2016, data of CML-CP patients in Peking University People's Hospital which were not enrolled in clinical trials were retrospectively collected and analyzed. Results: Data of 662 CML-CP patients were collected. With a median follow-up after TKI-therapy of 26 months (range, 3-187 months) , 187 patients (28.2%) experienced TKI cessation of at least 2 weeks. Causes of TKI discontinuation included hematologic adverse events 57.8% (n=108) , non-hematologic adverse events 30.4% (n=57) , financial burden 25.1% (n=47) , and others 7.0% (n= 13) . Multivariate analyses showed female, ≥40 years, no co-morbidity, and interval from diagnosis to TKI initiation ≥6 months, TKI switch and patients from other hospitals were factors associated with TKI discontinuation because of hematologic adverse effects. Female and patients from other hospitals were factors associated with TKI discontinuation because of non-hematologic adverse effect. TKI switch, generic TKI used and patients from other hospitals were factors associated with TKI discontinuation because of financial toxicity. Patients TKI discontinuation because of hematologic, non-hematologic or financial toxicity achieved a lower complete cytogenetic response or complete molecular response (CMR) than those with uninterrupted TKI-therapy. Patients with TKI discontinuation because of hematologic or financial toxicity had a shorter progression-free survival than those with uninterrupted TKI-therapy. 5 of 7 patients who obtained sustained CMR and discontinued TKI-therapy experienced disease recurrence with a median duration of 3 months (range, 2-32 months) . In 39 patients from other hospitals who aimed to confirm their optimal response of sustained CMR in Peking University People's Hospital, 21 (53.8%) were BCR-ABL positive. Conclusion: In the real world in China, half of CML-CP patients who discontinued TKI-therapy were incurred to TKI-related hematologic adverse effect, and both a quarter of them, TKI-related non-hematologic toxicities and financial toxicity, respectively. Discontinued TKI-therapy due to hematologic adverse events or financial toxicity was associated with lower TKI-therapy response rates. Nowadays, based on the Chinese situation, it is too early to talk about TFR.