In this study, researchers evaluated treatment with fludarabine and busulfan administered in a timed sequential regimen versus a reduced-intensity conditioning (RIC) regimen. Outcomes were assessed in an older patient population.
To be eligible for the study, patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) were required to have adequate organ function, a matched related or unrelated donor, and received treatment between January 2012 and September 2016. Patients in the timed sequential cohort received intravenous (IV) busulfan 80 mg/m2 per day on days -13 and -12 and fludarabine 40 mg/m2 per day followed by IV busulfan on days -6 to -3. Patients in the RIC cohort received fludarabine 40 mg/m2 per day followed by IV busulfan daily for 4 days (days -6 to -3).
The study population comprised 162 patients, 50 with MDS and 112 with AML. Patient characteristics were well-balanced and without any significant difference in the 2 cohorts. The median age was 65 years in the timed sequential group and 66 years in the RIC group.
Two-year overall survival (51% vs 31%; P = 0.01) and progression-free survival (PFS; 45% vs 24%; P = 0.004) were significantly better in the timed sequential group. At 2 years, 59% of patients in the RIC group had progressed compared with 34% of patients in the timed sequential group (P = 0.003) The data indicate that there was a reduction in disease progression without any increase in nonrelapse mortality. The difference in PFS persisted after adjustment for other covariates. The researchers concluded that the timed sequential busulfan regimen improves survival and appears promising in older patients with AML and MDS.
Popat UR, et al. ASCO Abstract 7046.