Availability of Suitable Domestic Cord Blood Grafts for Adult Allograft Recipients With Hematologic Malignancies

Although 8/8 HLA-allele matched unrelated donors (URDs) are commonly used, the majority of non-European ancestry allograft candidates lack an available 8/8 URD thereby necessitating an alternative donor. While HLA-mismatched unrelated or haploidentical related donors can extend access, major barriers to access persist, disproportionately impacting non-European ancestry patients or those requiring urgent transplantation. Cord blood (CB) could partially address these barriers but is increasingly underutilized. We investigated the ability of CB to overcome donor access inequities by studying our diverse patient population. Our hypothesis was the majority of adult patients have suitable double unit CB (dCB) grafts in the US inventory. We performed 3 analyses. Firstly, between July 2024 to September 2024, we performed mock CB searches on recipients of adult donor allografts transplanted 1/1/2020-9/30/2024 at our Center (Cohort 1). A suitable double unit (dCB) graft fulfilling American Society for Transplantation and Cellular Therapy (ASTCT) guidelines was selected if available. Second, we evaluated graft characteristics in recent dCB recipients transplanted September 1, 2023 to September 30, 2024 (Cohort 2). Third, we combined Cohort 1 and 2 patients with suitable dCB grafts to evaluate the ability of the 2024 US CB inventory to provide suitable grafts for a diverse patient population. Based on the 2024 inventory, a dCB graft was identified for nearly all Cohort 1 patients (215/224, 96%), including over 90% of European (138/141, 98%) and non-European (77/83, 93%) patients. Non-European ancestry patients trended toward a lower proportion having dCB grafts (P = .060). Of 30 patients >100 kg, 24/30 (80%) had a suitable graft, although the median weight of the 9 patients without a graft was 106 kg (range 74 to 137 kg). The 16 Cohort 2 dCB recipients [median weight 71 kg (range 51 to 118), 11 non-European] received median CD34+/kg cell doses of 2.5 × 10^5 and 1.9 × 10^5 per unit, respectively, and units were predominantly 4/8 HLA-matched. Of the total patient cohort, 200/240 (83%) patients had domestic dCB grafts. Excluding those without a dCB graft, selected grafts were domestic in 200/231 (87%), including most patients with European (120/143, 84%) or non-European (80/88, 91%) ancestry. Units were predominantly identified in US banks with the largest inventories. Based on the 2024 domestic inventory, our analysis suggests that CB could partially mitigate donor access disparities in minorities and act as a valuable potential alternative for urgent transplants. This is important given the ongoing barriers to transplant due to lack of unrelated donor availability. Our data highlight the potential of rapidly available domestic CB grafts to extend prompt transplantation access. Therefore, ongoing governmental funding of public CB banks to maintain and grow the domestic CB inventory, as well as efforts to ensure transplant center expertise in CB transplantation, are critical.