A Multicenter, Randomized, Open-Label Study to Analyze the Efficacy of Unrelated Cord Blood Combined With Haploidentical Stem Cell Transplantation in Patients With Aplastic Anemia
Aplastic anemia (AA) is a bone marrow failure disorder characterized by pancytopenia and hypoplastic bone marrow caused by the decrease of hematopoietic stem cells. The pathogenesis of AA is complex and involves an abnormal hematopoietic microenvironment, hematopoietic stem cell/progenitor cell deficiencies and immunity disorders. Currently, the standard treatment for AA includes immunosuppressive therapy (IST) based on anti-thymocyte/lymphocyte globulin (ATG/ALG) and cyclosporine A (CsA) or hematopoietic stem cell transplantation (HSCT). Although HLA-identical sibling allogeneic hematopoietic stem cell transplantation is considered the preferred transplant option for patients with severe aplastic anemia (SAA), only less than 30% of patients have an available HLA-matched sibling donor. In recent years, haploidentical hematopoietic cell transplantation (Haplo-HCT) has developed rapidly and has become an important alternative. However, graft failure and graft-versus-host disease (GVHD) remain significant factors limiting its efficacy. Umbilical cord blood (UCB) contains a diverse population of hematopoietic stem cells. Compared with other sources, cord blood-derived hematopoietic stem cells are more primitive, more viable, and possess higher proliferative capacity. Therefore, cord blood transplantation, with its notable clinical therapeutic effects, has become an effective and reliable alternative to peripheral blood or bone marrow transplantation. Currently, some transplant centers worldwide have adopted the coinfusion of UCB units with haplo-HCT (haplo-cord HCT) achieving preliminary efficacy in promoting engraftment and reducing the incidence of GVHD. A retrospective comparative study of haplo-cord HCT versus IST in patients with SAA identified haplo-cord HCT as the sole independent predictor for superior health-related quality of life (HRQoL) (P \< 0.0001). Based on existing research and clinical experience, this study plans to investigate and further evaluate the safety and efficacy of haplo-cord HCT in the treatment of aplastic anemia. Primary endpoints will include overall survival, engraftment rate, disease-free survival, incidence of GVHD, CMV/EBV reactivation rate, donor chimerism dynamics, and immune reconstitution.