The Efficacy and Long-Term Toxicity of Intravenous Busulfan and Cyclophosphamide Conditioning Regimen for Stem Cell Transplantation in Advanced Lymphoma.

Background: Although busulfan (Bu) in combination with cyclosphosphamide (Cy) is a commonly used conditioning regimen for the treatment of patients with hematologic diseases, its toxicity profile when administered intravenously (IV) as well as efficacy remains unclear, especially in the setting of autologous transplant for lymphoma.

Objective: To determine toxicity and the efficacy of the IV Bu/Cy conditioning regimen in patients who underwent autologous peripheral stem cell transplantation (APSCT) for the treatment of lymphoma.

Methods: A retrospective analysis was performed in 37 patients (21 male; 16 female) who underwent APSCT and received IV Bu/Cy regimen between January 2000 and May 2004.

Results: The median age was 50 years old (range: 20–68). Forty-seven percent of the patients were heavily pretreated (≥ 3 previous treatment, range 2–5). The distribution of lymphoma was: diffuse large B-cell lymphoma (DLBCL, 23), follicular lymphoma (8), mantle cell lymphoma (MCL, 5), and T-cell lymphoma (1). All patients received IV busulfan 3.2 mg/kg and cyclophosphamide 120 mg/kg, and were evaluable for toxicity. The patients engrafted (ANC ≥ 500 μ/l) at a median of 11 days (range: 9–14), and sustained platelet count (≥ 20,000 μ/l) at a median of 11 days (range: 8–42). The most common toxicities encountered were grade 1–2 including nausea, vomiting, stomatitis, esophagitis, and diarrhea. Grade 3–4 toxicities included hepatic veno-occlusive disease (HVOD, n=2), SIADH (n=1), and atrial fibrillation (n=2). Treatment related mortality (TRM) was seen in 3 patients due to HVOD (n=2) and septic shock (n=1). Twenty patients are still alive and 18 have no evidence of disease progression, with a median follow up of 17 months (range: 2–54 months). Kaplan-Meir actuarial OS at 24 months was 55.3% with a 47.3% DFS. Median event-free survival was 24 months (range 2–52).

Conclusions: IV Bu/Cy is a well-tolerated conditioning regimen with acceptable TRM, when compared with other regimens in heavily pretreated patients. The risk for HVOD is low. Further prospective trials are necessary to evaluate the role of Bu/Cy regimen in autologous stem cell transplant for lymphoma.