Subsequent attempt tyrosine kinase inhibitor discontinuation in patients with chronic myeloid leukemia; a single institute experience.

Discontinuation of tyrosine kinase inhibitors (TKIs) is now a feasible therapeutic goal for patients with chronic phase chronic myeloid leukemia (CML-CP). Whereas approximately half of patients experience molecular relapse, after resuming with any TKI; the majority re-achieve a deep molecular response (DMR). It is unclear whether such patients who re-achieve a durable DMR can discontinue TKI safely again. Here, we retrospectively assessed first, second, and third attempts to stop TKIs in patients with CML-CP. At the first attempt, 28 out of a total of 53 patients achieved sustained treatment-free remission (TFR; 53.4%; 95% confidence interval [CI], 39.0%-65.9%). Subsequently, 10 of 25 patients attempted a second TKI discontinuation, and in all cases, this was after receiving second-generation TKIs. Four of 10 patients successfully achieved TFR (37.5%; 95% CI, 9.9%-65.9%). All patients who relapsed at the second TKI discontinuation attempt were re-administered TKIs, and soon achieved at least a major molecular remission. All six second relapse patients had a loss of MR4.5 at 3 months after TKI discontinuation. These findings suggest that second and third attempts to successfully stop TKI treatment are feasible in patients with CML-CP.