Probability of sustained remission according to combined FC MRD results, relative and absolute estimate, from day 33 and week 12.

Kaplan-Meier calculations of the pRFI were based on intervals from week 12 onward. Three-year estimates of pRFI including SDs and log-rank test results are also shown. By relative assessment, MRD values of at least 0.1% leukemic cells among total BM NCs at day 33 in combination with at least 0.01% at week 12 were classified as high MRD load (versus all others). By absolute estimation, at least 10 leukemic cells/μL BM at day 33 in combination with at least 1 blast/μL at week 12 were classified high MRD. Of note, patients with high MRD load at day 33, but whose leukemic cells were cleared below the relevant thresholds by week 12 (n = 7 and 5, respectively) were subsumed in the MRD low-load groups. All these patients stayed relapse-free except for one patient of the relative-estimate series, who, in contrast, had been assigned to the MRD high-load group at week 12 by absolute counting.