Promising results of cord-blood transplants from unrelated donors have been reported in adults. We compared outcomes in 682 adults with acute leukemia who received a hematopoietic stem-cell transplant from an unrelated donor: 98 received cord blood and 584 received bone marrow. The transplantations were performed from 1998 through 2002 and reported to Eurocord and the European Blood and Marrow Transplant Group. Recipients of cord blood were younger than recipients of bone marrow (median, 24.5 vs. 32 years of age; P<0.001), weighed less (median, 58 vs. 68 kg; P<0.001), and had more advanced disease at the time of transplantation (52 percent vs. 33 percent, P<0.001). All marrow transplants were HLA matched, whereas 94 percent of cord-blood grafts were HLA mismatched (P<0.001). The median number of nucleated cells that were infused was 0.23×10⁸ per kilogram of the recipient's body weight for cord blood and 2.9×10⁸ per kilogram for bone marrow (P<0.001). Multivariate analysis showed lower risks of grade II, III, or IV acute graft-versus-host disease (GVHD) after cord-blood transplantation (relative risk, 0.57; 95 percent confidence interval, 0.37 to 0.87; P=0.01), but neutrophil recovery was significantly delayed (relative risk, 0.49; 95 percent confidence interval, 0.41 to 0.58; P<0.001). The incidence of chronic GVHD, transplantation-related mortality, relapse rate, and leukemia-free survival were not significantly different in the two groups. Cord blood from an unrelated donor is an alternative source of hematopoietic stem cells for adults with acute leukemia who lack an HLA-matched bone marrow donor.

In order to compare the outcomes of unrelated umbilical cord blood transplants (UCBTs) or bone marrow transplants, 541 children with acute leukemia (AL) transplanted with umbilical cord blood (n = 99), T-cell-depleted unrelated bone marrow transplants (T-UBMT) (n = 180), or nonmanipulated (UBMT) (n = 262), were analyzed in a retrospective multicenter study. Comparisons were performed after adjustment for patient, disease, and transplant variables. The major difference between the 3 groups was the higher number in the UCBT group of HLA mismatches (defined by serology for class I and molecular typing for DRB1). The donor was HLA mismatched in 92% of UCBTs, in 18% of UBMTs, and in 43% of T-UBMTs (P <.001). Other significant differences were observed in pretransplant disease characteristics, preparative regimens, graft-versus-host disease (GVHD) prophylaxis, and number of cells infused. Nonadjusted estimates of 2-year survival and event-free survival rates were 49% and 43%, respectively, in the UBMT group, 41% and 37% in the T-UBMT group, and 35% and 31% in the UCBT group. After adjustment, differences in outcomes appeared in the first 100 days after the transplantation. Compared with UBMT recipients, UCBT recipients had delayed hematopoietic recovery (Hazard ratio [HR] = 0.37; 95% confidence interval [95CI]: 0.27-0.52; P <.001), increased 100 day transplant-related mortality (HR = 2.13; 95CI: 1.20-3.76; P <.01) and decreased acute graft-versus-host disease (aGVHD) (HR = 0.50; 95CI: 0.34-0.73; P <.001). T-UBMT recipients had decreased aGVHD (HR = 0.25; 95CI: 0.17-0.36; P <.0001) and increased risk of relapse (HR = 1.96; 95CI: 1.11-3.45; P =.02). After day 100 posttransplant, the 3 groups achieved similar results in terms of relapse. Chronic GVHD was decreased after T-UBMT (HR = 0.21; 95CI: 0.11-0.37; P <.0001) and UCBT (HR = 0.24; 95CI: 0.01-0.66; P =.002), and overall mortality was higher in T-UBMT recipients (HR = 1.39; 95CI: 0.97-1.99; P <.07). In conclusion, the use of UCBT, as a source of hematopoietic stem cells, is a reasonable option for children with AL lacking an acceptably matched unrelated marrow donor.

The choice of either induction or postremission therapy for adults with acute myeloid leukemia is still largely based on the “one size fits all” principle. Moreover, pretreatment prognostic parameters, especially chromosome and gene abnormalities, may fail in predicting individual patient outcome. Measurement of minimal residual disease (MRD) is nowadays recognized as a potential critical tool to assess the quality of response after chemotherapy and to plan postremission strategies that are, therefore, driven by the individual risk of relapse. PCR and multiparametric flow cytometry have become the most popular methods to investigate MRD because they have been established as sensitive and specific enough to allow MRD to be studied serially. In the present review, we examine the evidence supporting the appropriateness of incorporating MRD detection into the AML risk assessment process. A comprehensive prognostic algorithm, generated by combining pretreatment cytogenetics/genetics and posttreatment MRD determination, should promote advances in development of personalized therapeutic approaches.