Long-term benefits for patients with hematologic malignancies were seen with allogeneic hematopoietic stem cell transplantation (allo-HSCT) and omidubicel, in comparison with umbilical cord blood transplantation (UCBT). This is according to follow-up results of a phase 3 trial presented at the 2022 Tandem Meetings by Mitchell E Horwitz, MD, of Duke University Medical Center, and colleagues.
Omidubicel is a cell therapy associated with preserved stem cell function and optimized homing and self-renewal, according to the researchers. Earlier trial analyses of primary and secondary end points suggested the combination of allo-HSCT and omidubicel was superior to standard UCBT in this study population. In the current analysis, Dr Horwitz and colleagues presented follow-up results from 1 year after transplantation.
The randomized, multicenter study included patients with hematologic malignancies from 7 nations. The follow-up report emphasized end points of 1-year nonrelapse mortality (NRM), disease-free survival (DFS), overall survival (OS), relapse, and grade 3 viral infections that occurred by 15 months postrandomization. However, the study was not powered to determine statistical differences between treatment arms for these analyses.
The median follow-up for the presented analysis was 14 months (range, 1-20). The study population consisted of 125 patients, many of whom had acute leukemia and moderate to high disease risk. The median patient age was 41 years.
The 1-year cumulative incidence of NRM for patients in this analysis was 15% for those in the arm receiving allo-HSCT with omidubicel (omidubicel arm), and it was 29% for patients in the UCBT arm (P =.068). Survival rates were 73% for the omidubicel arm and 60% for the UCBT arm (P =.13). The adjusted hazard ratio for mortality trended toward favoring the omidubicel arm, at 0.61 (95% CI, 0.32-1.15; P =.075).
DFS was similar between treatment arms. The DFS rate was 63% for the omidubicel arm, and it was 56% for the UCBT arm (P =.4). Cumulative incidence of relapse was also similar between arms, at 23% for the omidubicel arm, and at 16% for the UCBT arm (P =.32).
The 1-year incidence of grade 3 viral infection was 8% for the omidubicel arm, and it was 27% for the UCBT arm (P =.04). The 1-year incidence of grade 2 or 3 bacterial or invasive fungal infections was 45% for the omidubicel arm, and it was 70% for the UCBT arm.
The researchers concluded that use of omidubicel was linked to long-term benefits over UCBT in terms of 1-year NRM and relapse rates. They also indicated the OS rates show a trend of favoring the omidubicel arm over time, and they considered the option of using omidubicel to be supported by its clinical benefit.
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Horwitz ME, Stiff P, Cutler C, et al. Allogeneic hematopoietic stem cell (allo-HSCT) transplant with omidubicel demonstrates sustained clinical improvement versus standard myeloablative umbilical cord blood transplantation (UCBT): final results of a phase III randomized, multicenter study. Presented at: 2022 Tandem Meetings; April 23-26, 2022. Abstract 86.