The main causes of allogeneic hematopoietic stem cell transplantation (allo-HSCT) failure are primary disease relapse and transplant-related complications, especially relapse. In recent years, with the development of transplantation technology, alternative donors such as HID and UCB have been widely used. But, these alternative donors are associated with high incidences of transplant-related complications and mortalities when compared with human leukocyte antigen (HLA)-matched donors. Some studies suggeted that mixed grafts might overcome the disadvantages of a single alternative graft. UCB transplant (UCBT) supported by third-party HID or HID transplants supported by third-party UCB has been reported to have rapid engraftment and low incidences of graft-versus-host-disease (GVHD), making survival improvement. However, most of these results came from single-arm studies. The comparative studies between haplo-PBSC+Cord and haplo-PBSC+BM are scarce in the setting of HID transplantation. In a retrospective study, the investigators found haplo-PBSC+Cord transplantation has superior DFS than haplo-PBSC+BM in hematological malignancies. To further confirmed this conclusion, the investigators plan to conduct a prospective, multicenter, phase 3 randomized controlled trial.
The objective of this study was to explore whether the combination with umbilical cord blood (UCB) is associated with superior disease-free survival (DFS) in the setting of haploidentical donors (HID) transplantation.