Transplantation of Ex Vivo Expanded Umbilical Cord Blood (NiCord) Decreases Early Infection and Hospitalization.

ABSTRACT

Delayed hematopoietic recovery contributes to increased infection risk following umbilical cord blood (UCB) transplantation. In a Phase 1 study, adult recipients of UCB stem cells cultured ex vivo for 3 weeks with nicotinamide (NiCord) had earlier median neutrophil recovery compared with historical controls. To evaluate the impact of faster neutrophil recovery on clinically relevant early outcomes, we reviewed infection episodes and hospitalization during the first 100 days in an enlarged cohort of 18 NiCord recipients compared with 86 standard UCB recipients at our institution. The median time to neutrophil engraftment was shorter in NiCord recipients compared with standard UCB recipients (12.5 days versus 26 days; P < .001). Compared with standard UCB recipients, NiCord recipients had a significantly reduced risk for total infection (RR, 0.69; P = .01), grade 2-3 (moderate to severe) infection (RR, 0.36; P < .001), bacterial infection (RR, 0.39; P = .003), and grade 2-3 bacterial infection (RR, 0.21; P = .003) by Poisson regression analysis; this effect persisted after adjustment for age, disease stage, and grade II-IV acute GVHD. NiCord recipients also had significantly more time out of the hospital in the first 100 days post-transplantation after adjustment for age and Karnofsky Performance Status (69.9 days versus 49.7 days; P = .005). Overall, transplantation of NiCord was associated with faster neutrophil engraftment, fewer total and bacterial infections, and shorter hospitalization in the first 100 days compared with standard UCB transplantation. In conclusion, rapid hematopoietic recovery from an ex vivo expanded UCB transplantation approach is associated with early clinical benefit.