OBJECTIVETo evaluate the efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) following reduced intensity conditioning (RIC) regimen for treatment of refractory leukemia.

METHODSTwenty patients with refractory leukemia received allo-HSCT following RIC regimen consisting of fludarabine plus small or moderate dose total body irradiation (TBI). Graft versus host disease (GVHD) prophylaxis was CsA plus mycophenolate mofetil (MMF) or short-term MTX, or these three drugs combination; CD25 monoclone antibody(McAb) and ATG were also used in some of the patients.

RESULTSSeventeen patients engrafted successfully, the median time for ANC > 0.5 x 10(9)/L was 13 (11 - 17) days, and for BPC > 50 x 10(9)/L 19 (12 -42) days. Detected by short tandem repeat (STR)-PCR, complete donor chimerism was confirmed in 16 patients with a median of 14 (7 -35) days. The incidence of acute and chronic GVHD was 47.1% (8/17) and 38.5% (5/13) respectively. The transplant related mortality (TRM) was 25.0% (5/20), mainly from graft failure, intracranial hemorrhage and severe infection. Up to now, 7 patients relapsed and 9 were alive with leukemia free. The overall survival (OS) at 2 year was (35. 3 +/- 14.2)% for all patients and (52.5 +/- 18.6)% for acute non-lymphocytic leukemia (ANLL) patients.

CONCLUSIONAllo-HSCT following fludarabine and TBI based RIC regimen can be used for treatment of refractory leukemia with well tolerance and low TRM and there is a better prognosis for ANLL patients than that for acute lymphocytic leukemia patients.