Efficacy analysis of unrelated donor hematopoietic stem cell transplantation for treatment of high risk acute myeloid leukemia

Abstract

This study was purposed to investigate the therapeutic efficacy of unrelated donor hematopoietic stem cell transplantation (URD-HSCT) for patients with high risk and refractory acute myeloid leukemia (AML). Twenty-two patients with high-risk and refractory AML receive URD-HSCT were enrolled in this study. All the patients received myeloablative preconditioning regimen consisting of busulfan/cyclophosphamide (for 20 cases) or total body irradiation/cyclophosphamide (for 2 cases) before URD-HSCT. The cyclosporin A (CsA)/MTX/MMF/ATG were used to prevent the acute graft versus host disease (aGVHD). The results showed that 21 out of 22 patients acquired engraftment with implantation rate 95.5%. The median time of ANC ≥ 0.5×10(9)/L was 12 (10-19) days, and that of Plt ≥ 20×10(9)/L was 14 (5 - 22) days. The median follow-up time post transplantation was 18 (3 to 135.5) months. The 2-year overall survival (OS) and leukemia-free survival (LFS) were (53.9 ± 12.2) % and (49.1 ± 10.7)% respectively. Eight cases developed aGVHD. The cumulative incidence of aGVHD was (39.1 ± 10.6) %. Six patients developed I-II grade of aGVHD and two patients developed III-IV grade of aGVHD. The chronic graft versus host disease (cGVHD) was occurred in 6 patients (4 patients limited, 2 patients extensive) of the 19 evaluable patients. The cumulative incidence was (28.8 ± 9.6)%. Seven cases relapsed, and the cumulative response rate of 2 years was (35.8 ± 11) %. One of 9 patients died from sepsis before hematopoietic reconstruction, one died from lung infection, Six died from relapse and one relapsed patient died from IV grade of aGVHD post chemotherapy and donor lymphocyte infusion (DLI). The univariate analysis revealed that relapse was the major factor for the OS, and the sex, age, preconditioning regimen, aGVHD and infection didn't significantly influence the efficacy of URD-HSCT. The survival of patients with cGVHD was superior to those who didn't have cGVHD (83.3% vs 37%, P = 0.152). It is concluded that URD-HSCT is a safe and effective therapy for high-risk AML patients without related donor. Notably, patients with cGVHD had a better survival. Relapse is an unfavourable factor for the efficacy of URD-HSCT and adoptive immunotherapy such as DLI can prevent it and improve the prognosis to achieve the long-time survival.