Posted: Wednesday, March 17, 2021
Treatment with a myeloablative, fractionated busulfan regimen appears to reduce relapse and improve survival compared with a standard, unfractionated busulfan regimen in older patients with acute myeloid leukemia (AML) and myelodysplastic syndrome—without increasing nonrelapse mortality—according to an observational study published in Cancer. “These data, which need to be confirmed in future, larger, prospective studies, may indicate a paradigm shift toward the use of myeloablative conditioning regimens given over a longer period in older transplantation recipients with AML and myelodysplastic syndrome,” stated Uday R. Popat, MD, MBA, of The University of Texas MD Anderson Cancer Center, Houston, and colleagues.
In this open-label, randomized, phase II trial, patients with AML or myelodysplastic syndrome received either a fractionated regimen of busulfan dosed to achieve an AUC of 20,000 μmol/minute over 2 weeks (n = 84) or a standard, nonfractionated, lower busulfan dose regimen of 16,000 μmol/minute over 4 days (n = 78). Both groups also received fludarabine at 40 mg/m2 intravenously for 4 days. Approximately one-half of patients were at least aged 65, and similar proportions of patients had poor-risk cytogenetics in the fractionated (38%) and unfractionated (42%) groups.
At 2 years, progression-free survival was significantly improved in the fractionated group compared with the unfractionated group (45% vs. 24%, P = .004), likely due to a significant reduction in disease progression (34% vs. 59%, P = .003). Overall survival was also significantly higher in the fractionated group (51% vs. 31%, P = .01). As for safety, the rates of acute graft-versus-host disease were similar between the arms; however, the incidence of chronic graft-versus-host disease was higher in the fractionated group (43% vs. 22%).
Disclosure: For full disclosures of the study authors, visit acsjournals.onlinelibrary.wiley.com.