Outcomes of myeloablative allogeneic hematopoietic cell transplantation with omidubicel vs alternative donor sources

Omidubicel is a nicotinamide-expanded stem cell product derived from umbilical cord blood (UCB). In a phase 3 randomized trial for high-risk hematologic malignancies, omidubicel had faster neutrophil engraftment and fewer infectious complications than standard UCB transplantation. However, the clinical outcomes of omidubicel relative to other stem cell donor sources are yet to be determined. Clinical data for patients who underwent allogeneic hematopoietic cell transplantation (HCT) with omidubicel and standard UCB were taken from the phase 3 trial. The Center for International Blood and Marrow Transplant Research (CIBMTR) registry provided contemporaneous comparator cohorts of patients who met the trial eligibility criteria and who received allogeneic HCT from matched unrelated (MUD), mismatched unrelated (7/8 MMUD), and haploidentical donors. A total of 951 patients met the eligibility criteria, including 52 for omidubicel, 56 for standard UCB, 65 for 7/8 MMUD, 450 for MUD, and 328 for haploidentical donors. Omidubicel was associated with more rapid neutrophil engraftment than all other donor sources but slower platelet engraftment relative to other donor sources aside from UCB. There were no significant differences in overall survival, disease-free survival, and nonrelapse mortality among the donor sources. Omidubicel had a higher incidence of grade 2 to 4 acute graft-versus-host disease (GVHD), but similar rates of grade 3 to 4 acute GVHD and chronic GVHD compared to the CIBMTR cohorts. These results support the role of omidubicel as a viable donor source in the current transplant landscape.