Treatment patterns and clinical outcomes in chronic myeloid leukemia treated with second-line nilotinib-association of molecular milestones and prognostic scores with deep molecular response: a real-world retrospective cohort study.

Real-world data on the treatment patterns and clinical outcomes of second-line nilotinib use in chronic myeloid leukemia (CML) remain limited, particularly regarding predictors of deep molecular response (DMR). To characterize treatment patterns and long-term clinical outcomes in patients with CML receiving second-line nilotinib and to evaluate whether early molecular milestones combined with baseline prognostic scores predict DMR. Retrospective, single-center real-world study conducted at a tertiary academic center between 2011 and 2025. The data of 45 patients with CML receiving second-line nilotinib because of imatinib resistance or intolerance were analyzed. Treatment patterns, including duration and reasons for switching therapy, were assessed. Baseline prognostic scores (Sokal, European Treatment and Outcome Study [EUTOS], EUTOS Long-Term Survival [ELTS], Hammersmith) were calculated, and molecular responses were assessed according to the European LeukemiaNet (ELN) criteria. Predictors of DMR were examined using univariate and multivariate logistic regression, and survival outcomes were estimated using Kaplan-Meier analysis. The median duration of nilotinib administration was 67.3 months, with 60% of patients achieving a best response of DMR and 46.7% maintaining a sustained DMR. Univariate analysis showed that a favorable Hammersmith score (p = 0.001), low ELTS risk (p = 0.028), and attainment of ELN-defined milestones at 6 (p = 0.020) and 12 months (p = 0.006) were significantly associated with DMR. Multivariate analysis demonstrated that the 12-month ELN milestone (p = 0.008) and favorable Hammersmith score (p = 0.023) were independently associated with a DMR. Patients achieving a DMR showed a nonsignificant trend toward improved overall survival. In this real-world cohort, a DMR and favorable survival outcomes were achieved when nilotinib was administered as second-line treatment. Integrating baseline prognostic scores with molecular milestones enables individualized monitoring and supports a sustained DMR as a marker of durable disease control.