OBJECTIVETo investigate the safety and efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for myelodysplastic syndrome (MDS) and secondary acute myelogenous leukemia (MDS-AML) using conditioning regimen with busulfan (Bu) and increased-dose of fludarabine (ID-Flu).

METHODSA total of 49 patients with MDS or MDS-AML were treated by allo-HSCT, the clinical data was analyzed retrospectively.

RESULTSAll patients achieved hematopoietic reconstitution. Neutrophil engraftment was at 10 - 22 days (median 13 days), and platelet engraftment was at 8 - 66 days (median 16 days). The cumulative incidences of Ⅱ-Ⅳ degree acute graft-versus-host disease (GVHD), hemorrhagic cystitis (HC), and hepatic venous occlusive disease (VOD) were 28.6%, 14.3% and 2.0%, respectively. The transplant-related mortality (TRM) was only 4.1% at 100d and 8.2% at 1-92 months of followed-up (median 14 months) period. Overall survival (OS) and disease free survival (DFS) was 75.5%, 73.5%, respectively. Kaplan-Meier curve showed that 3-year OS and 3-year DFS was (71.1 ± 7.8)%, (66.7 ± 8.3)%, respectively, with a relapse incidence (RI) 16.3%. OS for MDS and MDS-AML was 81.5% and 68.2%, and RI in two settings was 3.7%, 31.8%, respectively. OS for MDS-AML at complete remission (CR) and non-CR subgroup was 83.3% and 50.0%, respectively, while cumulative RR was 16.7% and 50.0%, respectively. OS and RI except for non-CR subgroup were 82.1% and 7.7%. Univariate analysis showed that pre-HSCT disease status had correlation with OS (P=0.031), but age, decitabine in conditioning regimen, stem cell source, HLA matching, patient-donor gender, dose of mononuclear cells and GVHD had no correlation with OS.

CONCLUSIONBu/ID-Flu conditioning regimen for MDS and MDS-AML has high efficiency, fewer complications, lower toxicity and TRM. The OS and DFS were higher and RI was lower except for refractory MDS-AML patients. The regimen is valuable for clinical application.