Myeloablative conditioning regimens in adult patients with acute myeloid leukemia undergoing allogeneic hematopoietic stem cell transplantation in complete remission: a systematic review and network meta-analysis

The optimal myeloablative conditioning (MAC) regimens in adult patients with acute myeloid leukemia (AML) undergoing allogeneic hemopoietic stem cell transplantation (allo-HSCT) in complete remission (CR) remain unclear. We performed a systematic review and network meta-analysis to compare the effects of different MAC regimens. Bayesian network meta-analysis was performed using WinBUGS version 1.4.3. The commonly used MAC regimen Bu/Cy (4-day busulfan for toal 16 mg/kg orally or 12.8 mg/kg intravenously, plus 2-day cyclophosphamide for toal 120 mg/kg intravenously) is chosen as the common comparator. Pooled hazard ratios (HRs) with the associated 95% credibility interval (95% CrI) are obtained for all comparisons. We included 19 eligible studies, involving 8104 AML patients and 9 MAC regimens. Compared with Bu/Cy, 3-day busulfan plus fludarabine and thiotepa (Bu3/Flu/TT) is associated with significantly better overall survival (HR, 0.70; 95% CrI, 0.51 to 0.96) and lower risk of relapse (HR, 0.59; 95% CrI, 0.35 to 0.98). Bu3/Flu/TT is also associated with superior overall survival than Cy/TBI (cyclophosphamide plus total body irradiation), and lower risk of relapse than Bu4/Flu (4-day busulfan plus fludarabine). These results suggest that thiotepa-based new MAC regimen Bu3/Flu/TT is associated with improved outcomes in AML patients undergoing allo-HSCT in CR and worth further investigation.