Double-unit cord blood transplantation (dCBT) can reduce the risk of relapse for patients with acute leukemia, when compared with matched related or unrelated T-cell-depleted (TCD) grafts, a study suggests. 

In fact, the study showed that progression-free survival (PFS) was lowest in patients who received a matched TCD from a sibling donor (SIB TCD). 

This may have been due to donor age, according to study author Ioannis Politikos, MD, of Memorial Sloan Kettering Cancer Center in New York, New York. Dr Politikos presented the study at the Tandem Meetings 2022.


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The researchers studied 280 adults with acute myeloid leukemia, acute lymphoblastic leukemia, or mixed phenotype acute leukemia. All patients were undergoing their first allogeneic stem cell transplant. 

The researchers compared outcomes between patients who received a SIB TCD (n=65), those who received an 8/8 HLA-matched unrelated TCD (n=102), and patients who received a dCBT (n=113).

The 3 groups were well balanced with regard to age, sex, diagnosis, disease characteristics, hematopoietic cell transplant comorbidity index (HCT-CI), remission status, minimal residual disease status, and genetic risk. 

However, the groups differed significantly with regard to graft characteristics. Sibling donors were older than matched unrelated donors (P <.001). Grafts from siblings and unrelated donors were fully matched (8/8), but cord blood was not (median, 5/8; range, 3-7). 

Among the TCD recipients, more than half received high-dose total body irradiation. All patients in the dCBT group received prophylaxis for graft vs host disease (GVHD). 

Results

dCBT recipients had significantly slower neutrophil recovery. At 45 days, the rate of neutrophil recovery was 99% in the SIB TCD group, 100% in the URD TCD group, and 96% in the dCBT group (P <.001).

Rates of grade 2-4 and 3-4 acute GVHD were significantly higher among dCBT recipients. At 100 days, the incidence of grade 2-4 acute GVHD was 17% in the SIB TCD group, 28% in the URD TCD group, and 79% in the dCBT group (P <.001). The rates of grade 3-4 acute GVHD were 0% for SIB TCD, 2% for URD TCD, and 18% for the dCBT group (P <.001).

The 3-year relapse rate was significantly lower among dCBT recipients. It was 30% in the SIB TCD group, 20% in the URD TCD group, and 11% in the dCBT group (P =.012). 

The 3-year transplant-related mortality rate was not significantly different between the groups. It was 19% in the SIB TCD group, 11% in the URD TCD group, and 18% in the dCBT group (P =.3). 

The 3-year PFS rate was lowest in the SIB TCD group. It was 51% in the SIB TCD group, 68% in the URD TCD group, and 72% in the dCBT group (P =.025). 

The 3-year overall survival (OS) rates were not significantly different between the groups. The OS rates were 64% in the SIB TCD group, 74% in the URD TCD group, and 78% in the dCBT group (P =.2).   

In a multivariate analysis, a higher HCT-CI score (P =.021) and older age (P =.018) were associated with an increased risk of transplant-related mortality. The risk of relapse was significantly increased with SIB TCD compared with dCBT and URD TCD (HR, 2.69; 95% CI, 1.35-5.38; P =.018). 

The multivariate analysis also showed that SIB TCD was associated with significantly worse PFS (HR, 1.85; 95% CI, 1.13-3.02; P =.045). Cytomegalovirus positivity was associated with significantly worse PFS (P <.001) and OS (P =.012). A higher HCT-CI score was associated with significantly worse PFS (P =.002) and OS (P <.001) as well.

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.

Reference

Politikos I, Flynn J, Devlin SM, et al. Double unit cord blood transplantation compares favorably to T-cell depleted matched adult donor transplantation for the treatment of acute leukemia due to a robust protection against relapse. Tandem Meetings 2022; April 23-26, 2022. Abstract 44.

This article originally appeared on Cancer Therapy Advisor