Hematologic Malignancy Requiring an Allogeneic Hematopoietic Stem Cell Transplant Lacking a Donor

This clinical study is testing a new way to improve stem cell transplants for adults with high-risk blood cancers, such as leukemia or myelodysplasia, who do not have a suitable donor. The transplant uses stem cells from umbilical cord blood that have been expanded in the lab using a molecule called UM171. Previous studies showed that UM171 helps these cells grow and work better, leading to faster blood count recovery and fewer complications. In this study, researchers are testing whether increasing the dose of UM171 during the lab expansion process can make the transplant less toxic. The hypothesis is that using a higher dose of UM171 to expand cord blood stem cells will help patients recover blood counts faster after transplant by improving the growth and function of the cells. This may lead to better immune recovery, fewer infections, shorter hospital stays, and improved overall outcomes. Only seven patients will be enrolled, and they will be followed for one year after their transplant.