[Analysis of treatment-free remission outcomes in patients with chronic myeloid leukemia who received sequential nilotinib therapy after achieving deep molecular response to imatinib].

Objective: To analyze the treatment-free remission (TFR) outcomes in patients with chronic myeloid leukemia (CML) treated sequentially with nilotinib (NIL) after achieving deep molecular response (DMR) to imatinib (IM). Methods: Retrospectively enrolled 103 CML patients from 6 hematological centers in Henan Province who chose sequential NIL therapy or continued IM therapy after achieving DMR to first-line IM from June 2, 2013 to August 30, 2022. Among them, 42 cases were treated with sequential NIL and 61 cases continued IM therapy. The 42 patients in the sequential NIL group were further divided into 3 subgroups based on the duration of DMR at switching to sequential NIL therapy: Group 1 (17 cases): DMR duration<12 months at switching to sequential NIL therapy; Group 2 (8 cases): DMR duration≥12 months to<24 months at switching to sequential NIL therapy; Group 3 (17 cases): DMR duration≥24 months at switching to sequential NIL therapy. Follow-up ended on January 9, 2024, with a median follow-up of 40 (16, 91) months for the sequential NIL group and 49 (21, 123) months for the continuous IM group. Survival curves were plotted using the Kaplan-Meier method and the log-rank test was performed to compare the TFR rates between groups. Results: There were 19 males and 23 females with a median age [M (Q₁, Q₃)] of 43 (31, 50) years in the sequential NIL group. There were 32 males and 29 females with a median age of 41 (31, 50) years in the continuous IM group. Kaplan-Meier survival curve analysis showed that the TFR rate was higher in the sequential NIL group than in the continuous IM group (88.1% vs 63.9%, P=0.005). The results of subgroup analysis showed that the TFR rates in Group 1, Group 2 and Group 3 were 94.1%, 87.5% and 82.4%, respectively, with no statistically significant differences (all P>0.05).The TFR rate in Group 1 was higher than in the continued IM group (P=0.017), and there were no statistically significant differences in Group 2 and Group 3 compared with the continuous IM group(all P>0.05). Conclusion: Sequential NIL therapy after achieving DMR with IM therapy can improve the TFR rate in CML patients, especially in those with DMR duration<12 months before switching to sequential NIL therapy.