Sequential intensified conditioning followed by graft-versus-leukemia induction could prevent relapse of refractory acute myeloid leukemia after allogeneic hematopoietic stem cell transplantation

Abstract

To explore the therapeutic effects of sequential intensified conditioning regimen followed by graft-versus-1eukemia (GVL) induction in allogeneic hematopoietic stem cell transplantation (allo-HSCT) for refractory advanced acute myeloid leukemia (AML). A total of 72 patients with refractory AML undergoing allo-HSCT from May 2001 to June 2013 were enrolled in this prospective study. Intensified conditioning included fludarabine + cytarabine plus total body irradiation + cyclophosphamide + etoposide. Cyclosporine A was withdrawn rapidly in a stepwise fashion if patients who did not experience acute graft-versus-host disease (aGVHD) at Day + 30 post-transplantation. Donor lymphocytes were infused in patients without grade II or more than grade II aGVHD at Day + 60 post-transplantation. The median follow-up time was 655 (1-4 200) d post-transplantation. Except for one died of infection and one died of regimen-related toxicity (RRT), the other 70 patients achieved complete remission at the time of neutrophil reconstitution. The mortality of RRT was 1.4% (1/72). The 1-year cumulative incidence of aGVHD and 2-year incidence of chronic GVHD (cGVHD) post-transplantation were 60.7% ± 5.0% and 58.5% ± 4.7%. The 5-year cumulative incidence of relapse post-transplantation was 29.6% ± 6.6%. The 5-year non-relapse mortality was 28.8% ± 6.0%. The 5-year overall and disease-free survival were 51.0% ± 6.5% and 49.9% ± 6.4%. Multivariate analysis revealed that donor lymphocyte infusion, cGVHD and bone marrow blasts at Day 0 were independent prognostic factors for relapse (HR (95% CI): 0.042 (0.007-0.688), 0.009 (0.003-0.345), 3.385 (1.451-7.899)) and survival (HR (95% CI): 0.315 (0.146-0.621), 0.416 (0.200-0.866), 1.332 (1.158-1.533)). The strategy of sequential intensified conditioning followed by GVL induction has an acceptable toxicity profile, and could decrease the relapse rate and improve the survival for refractory AML.