Background:Acute myeloid leukemia (AML) is a common hematologic malignancy in adults, with a particularly poor prognosis in elderly patients. Traditional treatments, such as intensive chemotherapy and allogeneic hematopoietic stem cell transplantation, often have high risks of complications and mortality in this population. Umbilical cord blood microtransplantation (UCBM) offers a potential alternative by combining low-intensity conditioning with HLA-mismatched cord blood, aiming to reduce treatment-related mortality while maintaining antileukemic effects. Previous studies have confirmed that UCBM can be safely applied in the consolidation treatment of AML, but its efficacy in elderly AML has not yet been verified by randomized controlled studies. This study evaluated the safety and efficacy of umbilical cord blood microtransplantation in the treatment of newly diagnosed elderly AML through a prospective, single-center, randomized controlled clinical trial.

Methods:The initial design was to enroll 57 cases, including 38 cases in the experimental group and 19 cases in the control group. Due to the lack of chemotherapy drugs during the implementation of the clinical trial, we terminated the clinical trial ahead of schedule. This prospective, single-center, randomized controlled trial enrolled 18 newly diagnosed elderly AML patients at Zhongnan Hospital of Wuhan University from January 2022 to June 2024. Patients were randomly assigned to either the UCBM group (n=9) or the control group (n=9). The UCBM group received induction chemotherapy with AZA+IA/DA or AZA+venetoclax, followed by consolidation therapy with AZA+Ara-C and UCBM. The control group received the same chemotherapy regimen without UCBM. The primary endpoints were hematopoietic recovery within one month after the first consolidation treatment, median survival time, and 1- and 2-year overall survival (OS) and leukemia-free survival (LFS) rates.

Findings: Within one month after the first consolidation treatment, 7 patients (77.8%) in the UCBM group achieved hematopoietic recovery compared to 3 patients (33.3%) in the control group. The median survival time was significantly longer in the UCBM group (25.27 months, 95% CI: 22.53-33.9) than in the control group (15.47 months, 95% CI: 8.8-21.73; p=0.019). The overall survival rates of the experimental group at 1 year and 2 years were 100% and 77.8% respectively, which were 33.3% and 55.6% better than those of the control group. The 1-year and 2-year leukemia-free survival rates were 55.6% and 44.4% respectively, which improved by 22.2% and 33.3% compared with the control group. Notably, no cases of graft-versus-host disease (GVHD) were observed in the UCBM group, and STR-PCR detection showed no donor chimerism within +7 to +30 days post-transplantation.

Conclusion: UCBM combined with traditional chemotherapy is a safe and effective treatment option for newly diagnosed elderly AML patients. It promotes hematopoietic recovery, prolongs median survival time, and improves 1- and 2-year OS and LFS rates without increasing the risk of GVHD. Further studies with larger cohorts and longer follow-up periods are warranted to confirm these findings and explore the underlying mechanisms.

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2025
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