Clinical Efficacy and Feasibility of an Intensive Preparative Regimen with Busulfan, Cyclophosphamide, and Total Body Irradiation Followed by Allogeneic Stem Cell Transplantation for Patients with Myeloid Malignancies.

Purpose: High-intensity conditioning regimens before allogeneic stem cell transplantation (all-SCT) could reduce relapse but may increase nonrelapse mortality. We have investigated the efficacy and feasibility of an intensive preparative regimen of busulfan (BU), cyclophosphamide (CY), and total body irradiation (TBI) for patients with myeloid malignancies.

Patients and methods: From November 1990 to February 2005, 80 patients (acute myeloid leukemia (AML) 33, chronic myeloid leukemia (CML) 29, myelodysplastic syndrome (MDS) 18) treated with BU (8 mg/kg), CY (120 mg/kg), and TBI (10 Gy) followed by related (n=46) or unrelated (n=34) allo-SCT. Thirty-eight consecutive patients with AML in 1st remission, CML in chronic phase, and MDS (refractory anemia) defined as a standard risk group, and 42 patients with advanced AML, CML, and MDS (more than 5% marrow blasts) defined as a poor risk group.

RESULTS: With a median follow-up was 6.9 years, the 7-year actuarial overall survival (OS) rate was 58% (standard risk 70% vs poor risk 47%, p=0.0076), and the probability of 7-year relapse rate was 18% (standard risk 17% vs poor risk 18%, p=0.4777). Nonrelapse mortality was 29% (standard risk 26%, poor risk 31%). Multivariate analysis indicated that age older than 40 years (p=0.018) and received allo-SCT before 1998 (p=0.006) had independent predictive value for nonrelapse mortality.

CONCLUSION: The BU- CY- TBI regimen resulted in decreased relapse, especially in poor risk patients. The results of this study suggested that the BU- CY- TBI is an effective and feasible preparative regimen for allo-SCT in patients with myeloid malignancies.