Treosulfan Fludarabine and 2 Gy Total Body Irradiation Followed by Allogeneic Hematopoietic Cell Transplantation in Patients with MDS and AML

摘要

Allogeneic hematopoietic cell transplantation (HCT) offers curative therapy for many patients with myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML). However, post-HCT relapse remains a major problem, particularly in patients with high-risk cytogenetics. In this prospective phase II trial we assessed the efficacy and toxicity of treosulfan, fludarabine and 2 Gy total body irradiation (TBI) as conditioning for allogeneic HCT in patients with MDS or AML.Ninety-six patients with MDS (n=36; 15 RMCD; 10 RAEB-1; 10 RAEB-2; 1 CMML-1) or AML (n=60; 35 CR1; 18 CR2; 3 advanced CR; 4 refractory relapse) were enrolled; median age was 51 (range: 1–60) years. Twelve patients had undergone a prior HCT with high intensity conditioning. Patients received intravenous (IV) treosulfan, 14 g/m²/day on days −6 to −4, IV fludarabine, 30 mg/m²/day on days −6 to −2, and 2 Gy TBI on day 0, followed by infusion of hematopoietic cells from related (n=27) or unrelated (n=69) donors. Graft-vs.-host disease prophylaxis consisted of tacrolimus and methotrexate.With a median follow-up of 30 months, the 2-year overall survival (OS), relapse incidence and non-relapse mortality were 73%, 27% and 8%, respectively. The incidences of grades II–IV (III–IV) acute and chronic graft-versus-host disease were 59% (10%) and 47%, respectively. Two-year OS was not significantly different between MDS patients with poor risk and good/intermediate risk cytogenetics (69% and 85%, respectively), or between AML patients with unfavorable and favorable/intermediate risk cytogenetics (64% and 76%, respectively). In AML patients, minimal residual disease (MRD; n=10) at the time of HCT predicted higher relapse incidence (70% vs. 18%) and lower OS (41% vs. 79%) at 2 years, when compared to patients without MRD.In conclusion, treosulfan, fludarabine and low-dose TBI provided effective conditioning for allogeneic HCT in patients with MDS or AML, and resulted in low relapse incidence, regardless of cytogenetic risk. In patients with AML, MRD at the time of HCT remained a risk factor for post-HCT relapse.