Allogeneic hematopoietic cell transplantation with cord blood versus mismatched unrelated donor with post-transplant cyclophosphamide in acute myeloid leukemia

Abstract

Background Allogeneic hematopoietic cell transplantation (allo-HCT) using a mismatched unrelated donor (MMUD) and cord blood transplantation (CBT) are valid alternatives for patients without a fully human leukocyte antigen (HLA)-matched donor. Here, we compared the allo-HCT outcomes of CBT versus single-allele-mismatched MMUD allo-HCT with post-transplant cyclophosphamide (PTCy) in acute myeloid leukemia. Methods Patients who underwent a first CBT without PTCy ( N \u2009=\u2009902) or allo-HCT from a (HLA 9/10) MMUD with PTCy ( N \u2009=\u2009280) were included in the study. A multivariate regression analysis was performed for the whole population. A matched-pair analysis was carried out by propensity score-based 1:1 matching of patients (177 pairs) with known cytogenetic risk. Results The incidence of grade II–IV and grade III–IV acute graft-versus-host disease (GVHD) at 6 months was 36% versus 32% ( p \u2009=\u20090.07) and 15% versus 11% ( p \u2009=\u20090.16) for CBT and MMUD cohorts, respectively. CBT was associated with a higher incidence of graft failure (11% vs. 4%, p \u2009<\u20090.01) and higher 2-year non-relapse mortality (NRM) (30% vs. 16%, p \u2009<\u20090.01) compared to MMUD. In the multivariate analysis, CBT was associated with a higher risk of, NRM (HR\u2009=\u20092.09, 95% CI 1.46–2.99, p \u2009<\u20090.0001), and relapse (HR\u2009=\u20091.35, 95% CI 1–1.83, p \u2009=\u20090.05), which resulted in worse leukemia-free survival (LFS) (HR\u2009=\u20091.68, 95% CI 1.34–2.12, p \u2009<\u20090.0001), overall survival (OS) (HR\u2009=\u20091.7, 95% CI 1.33–2.17, p \u2009<\u20090.0001), and GVHD-free, relapse-free survival (GRFS) (HR\u2009=\u20091.49, 95% CI 1.21–1.83, p \u2009<\u20090.0001) compared to MMUD. The risk of grade II–IV acute GVHD ( p \u2009=\u20090.052) and chronic GVHD ( p \u2009=\u20090.69) did not differ significantly between the cohorts. These results were confirmed in a matched-pair analysis. Conclusions CBT was associated with lower LFS, OS, and GRFS due to higher NRM, compared to MMUD allo-HCT with PTCy. In the absence of a fully matched donor, 9/10 MMUD with PTCy may be preferred over CBT.