Reduced-dose of Posttransplant Cyclophosphamide and Cotransplantation of Peripheral Blood Stem Cells and Human Umbilical Cord-derived Mesenchymal Stem Cells in Severe Aplastic Anemia

Abstract

Background Posttransplant cyclophosphamide (PTCY) as graft-versus-host disease (GVHD) prophylaxis is an effective strategie for patients receiving matched sibling donor hematopoietic stem cell transplantation (MSD-HSCT) and haploidentical HSCT (haplo-HSCT). Methods We evaluated the effectiveness and safety of reduced-dose cyclophosphamide, 20 mg/kg for 13 patients in the MSD-HSCT group and 25 mg/kg for 22 patients in the haplo-HSCT group, on days +3 and +4 combined with cotransplantation of peripheral blood stem cells (PBSCs) and human umbilical cord-derived mesenchymal stem cells (UC-MSCs) for patients with severe aplastic anemia (SAA) retrospectively. Results In the MSD-PTCY group, the times to neutrophil and platelet engraftment were significantly shorter than those in the MSD-control group (P<0.05), 11 (range 10 to 14) days and 12 (range 9 to 15) days. The cumulative incidence of acute GVHD (aGVHD) at day +100 (15.4%) was lower in the MSD-PTCY group than in the MSD-control group(P=0.050). No patient developed chronic GVHD (cGVHD). The 1-year overall survival (OS) and event-free survival (EFS) rates in the MSD-PTCY group were 100% and 92.3%. In the haplo-PTCY group, the times to neutrophil and platelet engraftment were significantly shorter than those in the haplo-control group (P<0.05), 12 (range 9 to 15) days and 11.5 (range 9 to 17) days. The cumulative incidences of aGVHD at day +100 and 1-year cGVHD in the haplo-PTCY group were 31.8% and 18.2%. The 1-year OS and EFS rates in the haplo-PTCY group were 81.8% and 66.9%. Conclusions Reduced-dose PTCY and cotransplantation of PBSCs and UC-MSCs is feasible for patients with SAA, especially for overcoming the high incidences of aGVHD and cGVHD due to PBSCs.