Extended long-term follow-up and the survival of Stop Imatinib study

The French Stop Imatinib study (STIM1) was one of the first trials to explore the possibility of discontinuing imatinib in patients with chronic myeloid leukemia (CML) who had achieved a sustained molecular response (at least a 4.5-log reduction). The stringent criteria for molecular recurrence (MRec) were defined as BCR::ABL1 transcript positivity confirmed by a second test showing either a 1-log increase or loss of major molecular response across consecutive assessments. This comprehensive update presents long-term follow-up data from the STIM1 study, with a median molecular follow-up of 12.8 years (range, 0.8-15). Results showed a molecular recurrence-free survival rate of 37% (95% confidence interval [CI], 28-48) at 120 months, and 35% (95% CI, 26-46) at 156 months after imatinib discontinuation. Importantly, no patients experienced CML progression during the follow-up. Overall survival rates were 97% (95% CI, 94-100) at 10 years and 88% (95% CI, 81-96) at 20 years. A case of late MRec, confirmed through DNA BCR::ABL1 breakpoint analysis and comparison at diagnosis and recurrence, indicated the persistence of the original disease rather than the onset of new CML. This study offers valuable insights into the safety and feasibility of imatinib discontinuation for patients with CML, supporting long-term remission while maintaining survival. This study was registered at ClinicalTrials.gov as #NCT00478985.