Salvage therapy for acute chemorefractory leukemia by allogeneic stem cell transplantation: the Korean experience

Little is known about the characteristics that make patients with acute leukemia suitable for undergoing salvage therapy by allogeneic hematopoietic stem cell transplantation (allo-HSCT). Here, we analyzed the clinical outcomes of 223 patients with acute leukemia who underwent allo-HSCT while not in complete remission (CR). The primary end points were overall survival (OS) and CR rate. CR was achieved in 79.8% of patients after allo-HSCT. Acute graft-versus-host disease (GVHD) was significantly associated with CR (P = 0.045). During a median follow-up of 30.1 months, the median OS was 6.1 months. OS was significantly longer in patients with good or standard risk cytogenetic characteristics than in those with poor risk cytogenetic characteristics (P = 0.029, P = 0.030, respectively). Patients who received allo-HSCT from a matched sibling donor had better survival than those with unrelated donors (P = 0.015). Primary chemorefractoriness was not associated with poor survival (P = 0.071). The number of chemotherapies before allo-HSCT was significantly correlated with outcome (P = 0.006). Chronic GVHD was a strong predictor of a longer OS (P = 0.025). In conclusion, survival of patients with primary chemorefractory acute leukemia is not lower when treated upfront with allo-HSCT. Hence, allo-HSCT should be actively considered in such patients. Acute and chronic GVHD is associated with better outcomes patients with acute leukemia who have undergone allo-HSCT and not achieved CR.