Comparable survival outcomes in HLA-Matched and haploidentical hematopoietic stem cell transplantation for severe aplastic anemia patients aged 40-50: A CBMTR Registry-based propensity score matching analysis over the last decade

Our study includes 278 patients aged between 40 and 50 years from 29 centers who received allogeneic hematopoietic stem cell transplantation (allo-HSCT) from matched sibling donors (MSDs) (n = 106) and haploidentical donors (HIDs) (n = 172) over the last decade. Univariate analysis revealed that HID recipients was associated with more serious disease severity, a delayed allo-HSCT after diagnosis, a higher pretransplant transfusion burden and poor performance status pre-transplant than MSD recipients in clinical settings. After these pretransplant clinical factors were well balanced following propensity score-matching (PSM), 80 matched pairs were selected for further analysis. Following PSM, the cumulative incidences of neutrophil were comparable between two matched groups (P = 0.14), while the 100-day engraftment rates of platelet were significant lower in HID-HCT (P < 0.001); The HID cohort showed higher cumulative incidence of grade II-IV acute graft-versus-host disease (GVHD) compared with MSD group (P = 0.04). In contrast, the incidence of severe (grade III-IV) acute GVHD and chronic GVHD were not statistically significant (severe acute GVHD P = 0.10; chronic GVHD P = 0.28). Our study observed comparable overall survival (OS) (P = 0.14); failure free survival (FFS) (P = 0.23); GVHD-free/relapse-free survival (GRFS) (P = 0.26) between matched HID and MSD recipients. In conclusion, our data indicates that allo-HSCT from an HID could be considered for SAA patients between 40 and 50 years old who do not have an MSD.