Reduced-intensity conditioning transplantation in myeloid malignancies

The development of non-myeloablative and reduced-intensity conditioning regimens has enabled older or medically infirm patients with myeloid malignancies to be treated with allogeneic hematopoietic cell transplantation (HCT). The regimens are sufficiently immunosuppressive to allow engraftment of allogeneic cells and they rely largely on graft-versus-leukemia effects rather than high-dose cytotoxic therapy to eliminate malignant cells. Overall 2-5-year survivals after allogeneic HCT in older patients with acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS) have ranged from 25% to 64%. Outcomes were comparable for human leukocyte antigen-matched related and unrelated grafts. The best results were seen in patients transplanted in the first or second remission. Relapse and progressive disease continue to be problems, particularly in patients with large tumor burdens at the time of HCT. Reduction of the tumor burden before HCT with targeted therapy such as radiolabelled anti-CD45 antibody may improve the outcome. Despite still existing problems, early results in elderly patients with AML/MDS have been encouraging.