Impact of Pretransplantation Minimal Residual Disease, As Detected by Multiparametric Flow Cytometry, on Outcome of Myeloablative Hematopoietic Cell Transplantation for Acute Myeloid Leukemia

Purpose Allogeneic hematopoietic cell transplantation (HCT) benefits many patients with acute myeloid leukemia (AML) in first remission. Hitherto, little attention has been given to the prognostic impact of pretransplantation minimal residual disease (MRD). Patients and Methods We retrospectively studied 99 consecutive patients receiving myeloablative HCT for AML in first morphologic remission. Ten-color multiparametric flow cytometry (MFC) was performed on bone marrow aspirates before HCT. MRD was identified as a cell population showing deviation from normal antigen expression patterns compared with normal or regenerating marrow. Any level of residual disease was considered MRD positive. Results Before HCT, 88 patients met morphologic criteria for complete remission (CR), whereas 11 had CR with incomplete blood count recovery (CRi). Twenty-four had MRD before HCT as determined by MFC. Two-year estimates of overall survival were 30.2% (range, 13.1% to 49.3%) and 76.6% (range, 64.4% to 85.1%) for MRD-posit...