Decitabine As Part of a Modified Bu-Cy Conditioning Regimen Significantly Improved the Outcome of High-Risk AML Patients Undergoing Allogeneic Hematopoietic Stem Cell Transplantation

Background:Relapse remains a major cause of death after allogeneic hematopoietic stem cell transplantation (allo-HSCT), especially in patients with high-risk acute myeloid leukemia (AML). Therefore, how to eradicate the minimal residual disease and prevent of relapse are of great importance to improve the outcome of allo-HSCT for these high risk AML patients.

Methods:We retrospectively investigated decitabine (DAC) as part of a modified Bu-Cy regimen for high-risk AML patientsundergoing allo-HSCT. Fifty-nine patients received DAC (20 mg/m²/d,i.v.) for 5 days, followed by modified Bu-Cy (DAC group). A control (CON) of 177 patients (pair-matched 1:3) received modified Bu-Cy only.

Results:Median follow-up was 402 (85-1504) days. There was no difference in graft versus-host disease occurrence. Treatment-related mortality (day 100) was 0% (DAC) and 6.2% (CON). The DAC group had better 2-year overall survival (OS, 77% versus 64%, P=0.018) and leukemia-free survival (LFS, 73% versus 56%, P=0.007). The differences were more substantial among patients with active disease: OS, 83% (DAC) versus 47% (CON), P=0.01 and LFS, 77% (DAC) versus 34% (CON), P=0.002. Median time to relapse was 187 days (DAC) versus 86 days (CON) and two-year relapse rates were 10% (DAC) and 49% (CON) for patients with active disease. Patients with cytogenetic monosomy 7 or 7q- abnormality responded better.

Conclusions: Our data indicate that novel conditioning regimen containing DAC may be an effective and well-tolerated strategy and confer a subgroup-specific survival advantage in high-risk AML patients undergoing allo-HSCT.