Effect of Conditioning Regimens and Graft-versus-Host Disease Prophylaxis on the Outcomes of Umbilical Cord Blood Transplantation Performed with Cyclophosphamide/Total Body Irradiation-Based Regimens.
Level 3 - non-randomized controlled study
Retrospective nationwide non-randomized comparative cohort study
PubMed 38081416 · doi:10.1016/j.jtct.2023.12.004
What was done
This nationwide retrospective cohort study evaluated the effects of conditioning regimens and graft-versus-host disease (GVHD) prophylaxis on outcomes of umbilical cord blood transplantation (UCBT) performed with cyclophosphamide (Cy)/total body irradiation (TBI)-based regimens. Outcomes were analyzed using multivariate analysis for overall survival (OS) across four disease cohorts: acute myeloid leukemia (AML; n = 1126), acute lymphoblastic leukemia (ALL; n = 620), myelodysplastic syndrome (MDS; n = 170), and lymphoma (n = 128).
What was found
Adding high-dose cytarabine to Cy/TBI significantly improved OS in the AML group (relative risk [RR], 0.76; P = .003) and the lymphoma group (RR, 0.54; P = .02), but not in ALL or MDS. In the ALL group, adding etoposide to Cy/TBI was associated with lower OS (RR, 1.45; P = .03). For GVHD prophylaxis, tacrolimus plus methotrexate was associated with lower OS compared with cyclosporine plus methotrexate in the AML group (RR, 1.26; P = .01), with no significant difference seen in other disease groups. Differences in OS were mainly driven by differences in relapse risk.
Why it matters
The findings show that conditioning and GVHD prophylaxis regimens affect UCBT outcomes differently depending on the underlying malignancy, supporting disease-specific regimen selection.
Limits
The study is retrospective and observational, making it susceptible to selection bias and unmeasured confounding. The abstract does not provide confidence intervals, absolute survival rates, toxicity data, or non-relapse mortality rates. Sample sizes for MDS (n = 170) and lymphoma (n = 128) were substantially smaller than for the acute leukemia cohorts.