[Efficacy and toxicity of intravenous busulfan-based conditioning before allogeneic peripheral blood stem cell transplantation for leukemia].

Background & Objective: Busulfan (Bu) is commonly used as a component of conditioning regimens for hematopoietic stem cell transplantation. Erratic gastrointestinal absorption as a result of oral administration of Bu not only affects the efficacy, but also increases the risk of toxicity. This study was to analyze the efficacy and toxicity of intravenous Bu and cyclophosphamide (Cy) conditioning before allogeneic peripheral blood stem cell transplantation (allo-PBSCT) for leukemia.

Methods: Fifteen leukemia patients received intravenous Bu/Cy conditioning before allo-PBSCT, while 20 patients received oral Bu/Cy conditioning. The responses and adverse events of the 2 groups were assessed.

Results: All 15 patients in intravenous Bu/Cy group had hematopoietic engraftment. The median time of engraftment was 12 (9-15) days for neutrophils and 15 (11-24) days for platelets. Of the 15 patients, 6 (40.0%) developed acute graft-versus-host disease (aGVHD), including 4 cases of grade I-II aGVHD and 2 cases of grade III-IV aGVHD; during conditioning, 7 (46.6%) had vomiting, 1 (6.7%) had oral mucositis, 1 (6.7%) had hemorrhagic cystitis, 2 (13.3%) had hepatic damage, none developed seizure. With a median follow-up of 180 days (range, 35-420 days), 14 (93.3%) patients were alive, 1 died of severe aGVHD accompanied fungal infection of the lung and central nerve system. The occurrence rates of hepatic damage and oral mucositis were significantly lower in intravenous Bu/Cy group than in oral Bu/Cy group (13.3% vs. 60.0%, 6.7% vs. 80.0%, P<0.01). There were no significant differences in hematopoietic reconstruction, aGVHD, stomatitis, gastrointestinal reaction, and hemorrhagic cystitis between the 2 groups (P>0.05).

Conclusion: The intravenous Bu/Cy conditioning before allo-PBSCT for leukemia has clear efficacy with low extramedullary toxicity.