Cladribine With Intermediate Cytarabine, G-CSF and VP16 Sequential With Fludarabine and Busulifan as Condoning Regimen for Refractory Acute Leukemia

For patients with refractory acute leukemia, allogeneic stem cell transplantation is the only curative therapy. Only 20% of patients may achieve long-term survival mostly due to relapse or nor-relapse mortality (NRM). In previous study, we demonstrated that intensive leukemia debulking chemotherapy FLAG-IDA sequential with Flu-BU conditioning is feasible with ~40% long-term survival. The most important cause of treatment failures were relapse and non-relpase mortality. The further analysis demonstrated that patients with higher bone marrow blast before allo-HSCT was associated with treatment failure and patients with poor perforce status or age over 45 had increased rate of NRM. To further optimization the protocol, we modified the chemotherapy with cladribine replacing fludarabine aiming a more potent anti-leukemia effect and replace idarubicin with VP-16. All patients will also receive post-transplantation maintenance therapy with low-dose decitabine (5mg/m2 daily for 5 days) to prevent the further reduce the relapse incidence. We anticipate LFS at 1 year should be above 50% and 1-year LFS of 20% is considered unacceptable.