[Clinical outcome of allogeneic hematopoietic stem cell transplantation with FLAG sequential busulfan/cyclophosphamide conditioning regimen for refractory/relapsed acute myeloid leukemia].

Objective: To investigate the therapeutic effects of allogeneic hematopoietic stem cell transplantation (allo-HSCT) with FLAG sequential busulfan/cyclophosphamide(Bu/Cy) conditioning regimen for refractory/relapsed acute myeloid leukemia. Methods: From February 2012 to June 2017, 21 patients with refractory/relapsed acute myeloid leukemia underwent allo-HSCT with FLAG sequential Bu/Cy conditioning regimen. Transplantation-related complications and clinical outcome were retrospectively analyzed. Results: After conditioning, no hepatic veno-occlusive disease (VOD) and grade Ⅲ hemorrhagic cystitis occurred. 76.2% (16/21) patients had fever with 4 septicemia. One patient died of septic shock before engraftment. Twenty patients achieved neutrophil engraftment with a median time of 13 days (range, 10 to 21 days). Seventeen patients achieved platelet engraftment with a median time of 18 days (range, 9 to 25 days). The cumulative incidence of acute graft-versus-host disease (aGVHD) was 39.5%, and 3 patients developed grade Ⅲ-Ⅳ aGVHD. Of 19 patients who survived more than 100 days after transplantation, 4 had local chronic graft-versus-host disease (cGVHD). Of 21 patients, the median survival time was 15 months (range, 0.5 to 67 months) post-transplantation. Transplantation-related mortality rate was 28.7%. Leukemia relapse occurred in 4 patients with a median time of 4 months (range, 3 to 8 months) after transplantation. The cumulative relapse rate at 1 year was 21.4%. The 1-year and 3-year overall survival (OS) rates were 60.7% and 54.9% respectively. Log-rank analysis revealed that bone marrow blasts ≥ 20% or extramedullary leukemia before transplantation, poor platelet engraftment and grade Ⅲ-Ⅳ aGVHD were significantly related to shortened OS (P<0.05). Conclusions: Allo-HSCT with FLAG sequential Bu/Cy conditioning regimen in patients with refractory/relapsed myeloid leukemia has acceptable transplantation-related risk and relapse rate. The 1-year and 3-year OS rates are comparable with those in remission patients.