Peripheral Blood Versus Bone Marrow Plus Peripheral Blood Grafts for Haploidentical Transplantation in Severe Aplastic Anemia

Severe aplastic anemia is a life-threatening bone marrow failure disorder. Haploidentical hematopoietic stem cell transplantation has become an important curative treatment option for patients who do not have an HLA-matched sibling donor. Traditionally, haploidentical transplantation for severe aplastic anemia uses a graft composed of granulocyte colony-stimulating factor-primed bone marrow plus peripheral blood stem cells. However, bone marrow collection is invasive and may increase donor burden. Peripheral blood stem cell collection is simpler and less invasive, but it remains unclear whether using peripheral blood stem cells alone provides similar clinical outcomes without increasing the risk of graft-versus-host disease. This multicenter, randomized, open-label, non-inferiority trial will compare granulocyte colony-stimulating factor-primed peripheral blood stem cells alone with granulocyte colony-stimulating factor-primed bone marrow plus peripheral blood stem cells as graft sources for haploidentical transplantation in patients with severe or very severe aplastic anemia. Participants will be randomly assigned in a 1:1 ratio to either graft source group. The primary outcome is the cumulative incidence of grade II-IV acute graft-versus-host disease within 100 days after transplantation. Secondary outcomes include engraftment, chronic graft-versus-host disease, infections, immune reconstitution, survival, and donor safety.