The Kinetics of Reduction of Minimal Residual Disease Impacts on Duration of Survival and Response of Adult Patients with Acute Myeloid Leukemia

By multiprametric flow cytometry, we have previously showed that MRD negativity, as defined by a number of BM residual leukemic cells (BMRLC) 61 yrs), all consisting in intensive induction and consolidation cycles, and, for patients aged 2.0×10−4 BMRLC) patients. After induction, 30 (29%) of 105 patients were MRDneg, the remaining 75 (71%) were MRDpos. Fifthy four of 75 (72%) patients in the MRDpos group underwent relapse at a median time of 13 months (range 1–120), while in the MRDneg group 14/30 (47%) had disease relapse at a median time of 21 months (range 4–147) (P=0.014). The 5-year actuarial probability of OS and RFS was 47% and 50%, respectively, for patients in the MRDneg group, compared to 27% and 25%, respectively, for those in the MRDpos group (P=0.031 and 0.008, respectively). Seven patients had early relapse after induction therapy and 98 proceeded to receive consolidation; of these, one died of septic shock and 97 were evaluable for successive MRD assessment. At the post-consolidation time point, 26 (27%) of 97 patiens were MRDneg whereas 71 (73%) were MRDpos. Six of 26 (23%) and 55 of 71 (77%) of patients in MRDneg and in MRDpos group underwent relapse at a median time of 73 months (range 3–147) and 12 months (range 2–120), respectively, (P