Sustained treatment-free remission in two chronic myeloid leukemia patients after asciminib discontinuation: a report of two cases

Selected chronic myeloid leukemia (CML) patients may discontinue their tyrosine kinase inihibitor (TKI) in an attempt to achieve sustained treatment-free remission (TFR), which mitigates therapy-related side effects and limits treatment costs. TFR has been extensively studied following the discontinuation of adenosine triphosphate (ATP) - competitive TKI. However, there is minimal data concerning TFR after the discontinuation of the novel TKI asciminib. Here, we present two CML patients intolerant to multiple ATP-competitive TKIs who achieved a deep molecular response (DMR) during asciminib treatment and sustained this remission after asciminib discontinuation. One of the cases developed transient myalgia and arthralgia after asciminib discontinuation consistent with a TKI withdrawal syndrome. Both patients have been free of molecular relapse for more than at least 8 months after TKI discontinuation without increase in molecular BCR::ABL1 signal. These two cases provide proof of principle that sustained TFR after discontinuing asciminib in CML patients is feasible.