Analysis of 3,843 Unrelated Donors (URD) for 455 Allograft Candidates Reveals Low URD Availability with Marked Racial/ Ethnic Disparities: Major Implications for Transplant Center & Registry Operations

• Published in: Blood 2023-11, Vol.142 (Supplement 1), p.5114-5114
• Main Authors: Fingrut, Warren B, Davis, Eric, Archer, Anne, Brown, Samantha, Devlin, Sean M., Nhaissi, Melissa, Rapoport, Candice, Chinapen, Stephanie, Kelly, Amanda, Wells, Deborah, Scaradavou, Andromachi, Gyurkocza, Boglarka, Papadopoulos, Esperanza B., Politikos, Ioannis, Shaffer, Brian C., Barker, Juliet N
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2023-180439

Introduction: Although hematologic malignancies patients (pts) often require urgent transplants, the degree to which unrelated donor (URD) availability is a barrier to prompt allografting is not established. Methods: We evaluated availability of requested URDs 1/2020-12/2022, overall & by pt ancestry, in 455 consecutive adults with acute leukemia, MDS or MPN who had a formal URD search & for whom ≥ 1 URDs were pursued for confirmatory typing (CT). We also examined donor location & Donor Readiness Score (DRS; the prediction of a donor's likelihood of availability for CT) by pt ancestry. We hypothesized that URD availability is a major barrier to transplant for underserved racial/ ethnic groups & this has not improved in the post-pandemic era. Results: Of 455 pts [median age 63 yrs, range 21-81; 250/455 (55%) with acute leukemia], 74% (335/455) had European (EURO) & 26% (120/455) non-European (non-EURO) ancestry. For these 455 pts, 3,843 URDs (median age 27 yrs, range 17-61; 1,951/3,843 [51%] male) were requested for CT or simultaneous CT-workup; 71% (2,730/3,843) of URDs were for EURO & 29% (1,113/3,843) for non-EURO pts; & 56% (2,140/3,843) were from domestic & 44% (1,703/3,843) international registries. Of 2,775 URDs with an assigned DRS, the median score was 63% (range 16-94%). URDs requested for non-EURO pts were more likely to be domestic [EUROs: 1,411/2,730 (52%) vs non-EUROs: 729/1,113 (65%), p < .001]. Also, URDs for non-EUROs had markedly lower median DRS (EUROs: 71% vs non-EUROs: 52%) with over 15x the proportion with DRS ≤ 30% [EUROs: 30/2,073 (1.5%) vs non-EUROs: 160/702 (23%), p < .001]. Table 1A-C outlines URD availability at CT & workup, overall & by pt ancestry. In summary: •At CT, per pt: More non-EURO pts had greater than 10 URDs requested (p = .045), less than 5 URDs that agreed to CT (p < .001), & at least 5 URDs unavailable (p < .001), compared with EUROs.•At workup, per pt: For over one-quarter (134/455, 29%), 3-5 URDs were requested. More non-EURO pts had less than 2 URDs that agreed to workup (p = .007) & at least 2 URDs unavailable (p = .017), compared with EUROs.•At CT: Only half (2,036/3,843, 53%) of requested URDs were available for CT or CT-workup. URDs were less likely to agree to CT if requested for non-EURO pts ( vs EUROs), if domestic ( vs international), or if lower DRS (p < .001 for each).•At workup: Of URDs requested for workup after CT, while 461/598 (77%) agreed, URDs requested for non-EURO pts were less likely to agree