Allogeneic hematopoietic cell transplantation (HCT) following reduced-intensity conditioning in patients with acute leukemias.

The majority of patients with acute leukemia enter complete remission following induction therapy, but relapse despite consolidation and maintenance chemotherapy. Allogeneic hematopoietic cell transplantation (HCT) is the most effective consolidation therapy but unfortunately associated with high transplant-related mortality (TRM). In order to decrease TRM but still apply a graft-versus-tumor effect, allogeneic HCT protocols with reduced-intensity conditioning were developed and more than 5000 HCT, of which 1500 for acute leukemia, performed. Detailed information is available on more than 400 patients with acute leukemia. The results, summarized in this article, confirm that reduced-intensity preparative regimens lead to full donor chimerism and to generation of graft-versus-leukemia (GvL) effects with curative potential in older patients (>60 years). Prospective-controlled clinical trials are needed in younger patients to compare results of HCT after reduced-intensity conditioning to those of HCT with conventional conditioning.