Comparison of Stem Cell Transplantation Using Unrelated, Haploidentical, and Sibling Donors for Patients with Acquired Severe Aplastic Anemia: A Single-Center Retrospective Cohort Study

Abstract

The preferred donor (haploidentical vs. matched unrelated donor) choice in patients with acquired severe aplastic anemia (SAA) who lack a human leukocyte antigen (HLA)-matched sibling donors (MSDs) and fail upfront immunosuppressive treatment (IST) therapy is unknown. We retrospectively investigated SAA patients (n=58) who underwent allogeneic stem cell transplantation (allo-SCT) between January 2012 and October 2022. The 5-year overall survival (OS) (87.5% ± 11.7% vs. 98.0% ± 6.5% vs. 83.3% ± 7.6%, respectively, p= 0.926) and 5-year failure-free survival (FFS) (60.0% ± 18.2% vs. 87.0% ± 7.0% vs. 78.3% ± 8.6%, respectively, p= 0.222) were comparable among the unrelated donors (URD; n=8), haploidentical donors (HID; n=25), and MSD cohorts (n=25). Multivariate analysis revealed that primary engraftment failure independently predicted OS, and secondary graft failure predicted FFS among SAA patients who underwent allo-SCT, although donor type and age did not predict the outcomes. An urgent second SCT for patients with engraftment failure may be an effective salvage treatment. Summarily, our findings showed that an alternative donor SCT is indicated for eligible SAA patients without MSDs even if these patients are aged ⩾ 40 years.