Cohort-Controlled Comparison of Umbilical Cord Blood Transplantation Using Carlecortemcel-L, a Single Progenitor–Enriched Cord Blood, to Double Cord Blood Unit Transplantation

•Expanding a portion of a UCB unit in cytokines with tetraethylenepentamine led to a median 77-fold expansion of CD34+ cells.•Compared with a contemporaneous double UCB cohort, transplantation of expanded and remaining unexpanded cells led to a lower 100-day mortality.•Faster neutrophil and platelet engraftment was also seen also for the group transplanted with the expanded cells. Umbilical cord blood (UCB) transplantation has a high early mortality rate primarily related to transplanted stem cell dose. To decrease early mortality and enhance engraftment, a portion of selected cord blood units (20% to 50%) was expanded with cytokines and the copper chelator tetraethylenepentamine (carlecortemcel-L) and transplanted with the unmanipulated fraction after myeloablative conditioning. The primary endpoint was 100-day survival, which was compared with a contemporaneous double-unit cord blood transplantation (DUCBT) group. We enrolled 101 patients at 25 sites; the DUCBT comparison (n = 295) was selected from international registries using study eligibility criteria. Baseline carlecortemcel-L study group unit nucleated cell (NC) and CD34+ were 3.06 × 107 cell dose/kg and 1.64 × 105 cell dose/kg. Median NC and CD34+ fold expansion were 400 and 77, with a mean total CD34 infused of 9.7 × 105/kg. The 100-day survival was 84.2% for the carlecortemcel-L study group versus 74.6% for the DUCBT group (odds ratio, .50; 95% CI, .26 to .95; P = .035). Survival at day 180 was similar for the 2 groups; the major cause of death after day 100 was opportunistic infections. Faster median neutrophil (21 days versus 28 days; P