Comparable Long-Term Outcome after Allogeneic Stem Cell Transplantation from Sibling and Matched Unrelated Donors in Patients with Acute Myeloid Leukemia Older Than 50 Years: A Report on Behalf of the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

Allogeneic stem cell transplantation (SCT) is potentially curative therapy in acute myeloid leukemia (AML). Marked improvement has been achieved with SCT from matched unrelated donors (MUDs) in recent years. However, there are limited data comparing the long-term outcomes (beyond 10 years) after SCT from sibling donors and MUDs in older patients with AML. We analyzed these outcomes in a large cohort of patients with AML (n = 1134), age ≥50 years, who were alive and leukemia-free 2 years after SCT from matched siblings (n = 848) or MUDs (n = 286), with a median follow-up of 8.9 years. The median age was 56 and 58 years after SCT from siblings and MUDs, respectively (P = .005). In the sibling group, 77%, 12%, and 11% were in first complete remission (CR1), second complete remission (CR2), and active leukemia at SCT compared with 50%, 25%, and 25% in the MUD group, respectively (P < .001). Sixty-one percent of siblings and 62% of MUDs had reduced-intensity conditioning (P = .78). The 10-year leukemia-free survival (LFS) of patients surviving leukemia-free 2 years after SCT was 72% and 62%, respectively (P = .30). Multivariate analysis identified active leukemia at SCT (hazard ratio [HR], 1.86; P = .0001) or CR2 (HR, 1.51; P = .02) compared with CR1, female recipients (HR, 0.71; P = .006), adverse cytogenetics (HR, 2.52; P = .01), and prior graft-versus-host disease (HR, 1.31; P = .04) as independent factors predicting LFS. Donor and conditioning type were not significant. The cumulative incidence was 15% and 17% (P = .97) for late relapse mortality and 13% and 21% for late nonrelapse mortality, respectively (P = .15). In conclusion, long-term LFS is similar, and patients who are leukemia-free 2 years after SCT can expect favorable outcomes with both donor types.

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