Unrelated Donor Peripheral Blood Stem Cell Transplantation for Patients with β-Thalassemia Major Based on a Novel Conditioning Regimen

Allogeneic hematopoietic stem cell transplantation (HSCT) is the only available curative treatment for patients with beta-thalassemia major (beta-TM). However, the problem of finding a suitable sibling donor with well-matched human leukocyte antigens is still a major obstacle to curing these patients. With the progress in high-resolution HLA typing technology and supportive care, outcomes after allogeneic HSCT from an HLA well-matched unrelated donor (UD) now approach those of well-matched sibling donors. However, UD HSCT is hampered by an increased risk of graft-versus-host disease and transplant-related mortality. Here we report the outcome of transplantation in patients with beta-TM using a novel WZ-14-TM transplant protocol, based on cyclophosphamide, intravenous busulfan, fludarabine, and antithymocyte globulin, in our center. Forty-eight patients between 2 and 11 years of age with beta-TM received HLA well-matched UD peripheral blood stem cell transplantation following the WZ-14-TM protocol. All of the transplanted patients achieved donor engraftment. The incidences of grade II to IV acute and chronic graft-versus-host disease were 8.3% and 8.3%, respectively. The overall survival and thalassemia-free survival rates were both 100%. This encouraging result suggests that the WZ-14-TM protocol is a feasible and safe conditioning regime for patients with beta-TM undergoing UD HSCT. (C) 2019 American Society for Blood and Marrow Transplantation.