The Outcomes of Single-unit Unrelated Umbilical Cord Blood Transplantation for Adult Acute Myeloid Leukemia with RUNX1::RUNX1T1 in Multicenter Retrospective analysis.

BACKGROUND: Acute myeloid leukemia (AML) with RUNX1::RUNX1T1 usually has a favorable outcome. However, it sometimes relapses and is refractory; in these cases, allogeneic hematopoietic stem cell transplantation (HSCT) is indicated. When HLA-matched sibling donors (MSDs) are unavailable, alternative donor sources, such as unrelated umbilical cord blood cells (UCB), are considered. However, the outcomes of UCB for AML with RUNX1::RUNX1T1 have not yet been fully examined. We retrospectively analyzed the outcomes of HSCT with UCB. METHODS: A total of 12 patients with AML with RUNX1::RUNX1T1 who received UCB transplantation between 2002 and 2022 in 3 transplantation centers in Miyagi Prefecture were included. The median age at transplantation was 32 years; ten patients chose myeloablative conditioning regimens, and 9 patients achieved complete remission just before HSCT. RESULTS: The 3-year overall survival and relapse-free survival were both 75.0%. All patients in complete remission (CR) before HSCT remained in remission during follow-up. The cumulative incidence of 3-year non-relapse mortality was 16.7%. CONCLUSION: These results indicate that UCB transplantation could be a feasible option for patients with relapse/refractory RUNX1::RUNX1T1-positive AML without MSDs.