Haploidentical hematopoietic cell transplantation with or without an unrelated cord blood unit for adult acute myeloid leukemia: a multicenter, randomized, open-label, phase 3 trial

Abstract

sCoinfusion of unrelated cord blood (UCB) units in haploidentical hematopoietic cell transplantation (haplo-HCT) (haplo-cord HCT) for hematopoietic malignancies showed promising results in previous reports, but the efficiency of haplo-cord HCT in acute myeloid leukemia (AML) still lacks sufficient evidence. This multicenter, randomized, phase 3 trial (ClinicalTrials.gov NCT03719534) aimed to assess the efficacy and safety of haplo-cord HCT in AML patients. A total of 268 eligible patients aged 18–60 years, diagnosed with measurable residual disease in AML (excluding acute promyelocytic leukemia), with available haploidentical donors and suitable for allotransplantation, were randomly allocated (1:1) to receive haplo-cord HCT (n = 134) or haplo-HCT (n = 134). The 3-year overall survival (OS) was the primary endpoint in this study. Overall median follow-up was 36.50 months (IQR 24.75–46.50). The 3-year OS of Haplo-cord HCT group was better than haplo-HCT group (80.5%, 95% confidence interval [CI]: 73.7–87.9 vs. 67.8% 95% CI 60.0–76.5, p = 0.013). Favorable progression-free survival (70.3%, 95% CI 62.6–78.8 vs. 57.6%, 95% CI 49.6–67.0, p = 0.012) and cumulative incidence of relapse (12.1%, 95% CI 12.0–12.2 vs. 30.3%, 95% CI 30.1–30.4, p = 0.024) were observed in haplo-cord HCT group. Grade 3–4 adverse events (AEs) within two years posttransplantation in the two groups were similar. Haplo-cord HCT patients exhibited a faster cumulative incidence of neutrophil recovery (p = 0.026) and increased T-cell reconstitution in the early period posttransplantation. Haplo-cord HCT can improve OS in AML patients without excessive AEs, which may exert additional benefits for recipients of haplo-HCT.