Busulfan, cyclophosphamide and fractionated total body irradiation as a preparatory regimen for marrow transplantation in patients with advanced hematological malignancies: a phase I study.

Thirty-six patients with advanced hematologic malignancy were entered into a phase I study designed to define a tolerable dose of busulfan (BU) and cyclophosphamide (CY) combined with 12 Gy of fractionated total body irradiation (TBI) as preparation for marrow transplantation from HLA-identical siblings, 0-1 locus HLA-non-identical family members or autologous cryopreserved marrow. Five of 18 evaluable patients prepared with 8.7 mg/kg of BU and 69 mg/kg CY + TBI developed severe regimen related toxicity (RRT) while none of 15 patients treated with 6.9 mg/kg of BU and 47 mg/kg of CY + TBI developed severe RRT. Ten of the 15 evaluable patients treated on the lower dose level are alive, nine disease-free, 262-737 days (median, 547) post-transplant with a 87% and 67% actuarial probability of survival at 3 and 18 months respectively. Six of the 18 patients treated on the higher dose level are alive disease-free 273-1039 days (median, 668) post-transplant with a 56% and 27% actuarial probability of survival at 3 and 18 months respectively. Eighteen patients were transplanted with allogeneic marrow for chronic myelogenous leukemia beyond chronic phase and acute non-lymphocytic leukemia beyond first remission or in relapse other than first untreated relapse and only one has relapsed posttransplant. It was concluded that a transplant preparative regimen combining 6.9 mg/kg of BU with 47 mg/kg of CY followed by 12 Gy fractionated TBI is well tolerated. The high probability of surviving this regimen and the low early relapse rate in patients with advanced myeloid malignancies is encouraging.

Duke Scholars

Author Keith Michael Sullivan Medicine, Hematologic Malignancies and Cellular Therapy