[A preliminary study on efficacy of allogeneic hematopoietic stem cell transplantation by myeloablative conditioning regimen with fludarabine for high risk leukemia patients].

The aim of this study was to explore the efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) by myeloablative conditioning regimen with fludarabine for high risk leukemia patients. 25 refractory and relapsed leukemia patients underwent allo-HSCT with new conditioning regimen consisted of fludarabine, busulfan and cyclophosphamide. Donors for 15 patients were sibling, but donors for the rest 10 patients were all unrelated. HLA matched and mismatched donors were for 15 and 10 patients respectively. The graft versus host disease (GVHD) prophylaxis included cyclosporine A and methotrexate, while mycophenolate mofetil and rabbit anti-T-lymphocyte globulin (ATG) were used in case of unrelated and HLA mismatched HSCT. The results showed that unrelated donor HSCT in 10 cases was successful (100%), 14 out of 15 patients with donors of sibling or parent also reconstructed their haematopoietic system. One mismatched patient (4/6) died of graft failure. The time from transplantation to ANC > 0.5 × 10(9)/L and Plt > 20 × 10(9)/L were 13 (11 - 19) days and 13 (12-20) days after transplantation respectively. The cumulative incidence of grade II-IV acute GVHD and chronic GVHD was 12.5% (3/24) and 47.4% (9/19), respectively. In a follow-up duration of 6-84 months, 12 patients were dead, out of which 8 died of relapse; 1 cases died of regimen-associated side effect. 3 cases died of serious infection. The other 13 patients remained alive and disease-free survival probability was 48.7%. It is concluded that allo-HSCT by myeloablative conditioning regimen with fludarabine is a safe and effective option for high risk leukemia patients, which reduces aGVHD incidence and regimen-associated side effect, but it should be modified for higher rate of relapse.