Research presented at the 64th American Hematology Association (ASH) Annual Meeting and Exposition suggests that race and ethnicity matching may have minimal to no impact on umbilical cord blood transplant (UCBT) patient outcomes. Researchers compared outcomes of non-Hispanic White (White), non-Hispanic Black (Black), Hispanic/Latinx (Latinx), and Asian recipients of UCBT using a more modern group of patients than previously studied. The results showed that overall survival (OS) has improved over time in adults and children across all racial and ethnic groups, but Latinx adults had worse OS compared to other groups.
Research on the impact of race and ethnicity on hematopoietic cell transplantation (HCT) outcomes can facilitate awareness to improve healthcare disparities and access to transplant. UCBT allows for the use of mismatched UCB units to improve access to HCT for patients lacking a fully matched donor (ethnically diverse patients are more likely to have a harder time finding a fully matched donor). A previous study by the CIBMTR® (Center for International Blood and Marrow Transplant Research®) showed that Black patients had a lower OS than White patients following single UCB transplant; however, outcomes were similar when UCB units of comparable cell dose and HLA match were used.
The study included patients aged 1 to 80 years (1,705 adults and 826 children) who received UCBT from 2007 through 2017. Of these patients, 983 received a single UCBT, and 1,259 received a doubled UCBT following either myeloablative or reduced intensity conditioning (RIC).
The primary outcome focus was OS at 2 years post-transplant, estimated by using the Kaplan-Meier method. Secondary outcomes were disease-free survival, transplant-related mortality (TRM), acute and chronic graft-versus-host disease (GVHD), and GVHD-free, relapse-free survival (GRFS).
The OS for adults improved over time across all racial and ethnic groups, yet Latinx adults had worse OS compared to the other patient groups, as shown in Figure 1 below. GVHD rates were comparable among the different racial and ethnic groups in adults. There was no significant difference in OS, relapse, or TRM among children within the racial and ethnic groups. The rate of acute GVHD was higher in Black children compared to White children. Results showed no survival advantage to receiving a UCB unit from a donor of similar race or ethnicity, for either the adults or children.
This study suggests there's little advantage to matching UCB unit to the same race or ethnicity as the patient for adults or children. UCB banks may have an opportunity to focus on the collection of larger units rather than race or ethnicity quotas.
OS in adults has improved over time for all racial and ethnic groups. However, adult Latinx patients showed worse relapse and mortality outcomes, and acute GVHD was worse in Black children than White children. More research is needed to determine the association of poor outcomes in these populations, which can lead to targeted initiatives to improve HCT access and outcomes.
Ballen K, et al., ASH oral presentation abstract