Clinical applicability of the ELN2020 criteria for tyrosine kinase inhibitor discontinuation in chronic myeloid leukemia: insights from a multicenter retrospective study in real-world practice

Abstract

The prognosis of chronic myeloid leukemia has significantly improved with the introduction of tyrosine kinase inhibitors (TKIs). However, indefinite TKI treatment can lead to adverse effects and high costs. Recent studies have suggested that treatment-free remission (TFR) is achievable in patients with a deep molecular response (DMR). The present multicenter, retrospective observational study conducted in Japan evaluated the applicability of the European LeukemiaNet (ELN) 2020 TKI discontinuation criteria, which recommend TKI therapy of ≥ 5 years with sustained MR⁴ for ≥ 3 years or MR^4.5 for ≥ 2 years. A total of 100 patients who discontinued TKI therapy were analyzed, with 70 meeting the ELN2020 criteria. The overall 12-month TFR rate was 71.9 %. Univariate analysis showed that both the duration of DMR and TKI therapy were significantly associated with TFR, with hazard ratios (HR) of 0.305 and 0.450, respectively. Only DMR duration remained significant (HR 0.362) in multivariate analysis. Patients who lost MMR after TKI discontinuation rapidly re-achieved molecular response upon TKI resumption. The most common reason for TKI discontinuation was elective cessation, followed by adverse events, among which pleural effusion due to dasatinib was the most frequent. The results of this study, the first to assess the ELN2020 criteria in a Japanese cohort, suggest that the criteria are applicable in real-world clinical practice.