Prospective cohort study comparing intravenous busulfan to total body irradiation in hematopoietic cell transplantation

Abstract

We conducted a prospective cohort study testing the noninferiority of survival of ablative intravenous busulfan (4-BU) vs ablative total body irradiation (TBI)-based regimens in myeloid malignancies. A total of 1483 patients undergoing transplantation for myeloid malignancies (4-BU, N 5 1025; TBI, N 5 458) were enrolled. Cohorts were similar with respect to age, gender, race, performance score, disease, and disease stage at transplantation. Most patients had acute myeloid leukemia (68% 4-BU, 78% TBI). Grafts were primarily peripheral blood (77%) from HLA-matched siblings (40%) or well-matched unrelated donors (48%). Two-year probabilities of survival (95%confidence interval [CI]),were 56% (95% CI, 53%-60%) and 48% (95% CI, 43%-54%, P 5 .019) for 4-BU (relative risk, 0.82; 95% CI, 0.68-0.98, P 5 .03) and TBI, respectively. Corresponding incidences of transplantrelated mortality (TRM) were 18% (95% CI, 16%-21%) and 19% (95% CI, 15%-23%, P 5 .75) and disease progression were 34%(95%CI, 31%-37%) and 39%(95%CI, 34%-44%, P5.08). The incidence of hepatic veno-occlusive disease (VOD) was 5% for 4-BU and 1% with TBI (P