Favorable preliminary results using TLI/ATG‐based immunomodulatory conditioning for matched unrelated donor allogeneic hematopoietic stem cell transplantation in pediatric severe aplastic anemia

Pillai A, Hartford C, Wang C, Pei D, Yang J, Srinivasan A, Triplett B, Dallas M, Leung W. Favorable preliminary results using TLI/ATG‐based immunomodulatory conditioning for matched unrelated donor allogeneic hematopoietic stem cell transplantation in pediatric severe aplastic anemia.
Pediatr Transplantation 2011: 15: 628–634. © 2011 John Wiley & Sons A/S. Abstract: To assess whether a tolerance‐induction regimen could be applied for unrelated (MUD) HCT in SAA, we retrospectively reviewed our HCT experience using unmanipulated 10/10 HLA‐matched bone marrow grafts from MSD vs. MUD donors. Conditioning was CTX 200 mg/kg (CTX) + rabbit ATG 10 mg/kg (ATG) for MSD (n = 9) and TLI (800 cGy) + CTX/ATG for MUD HCT (n = 5). Immunoprophylaxis was CSA and short‐course MTX. Median patient age was 14.7 yr, median time to HCT 1.5 yr, and median follow‐up 3 yr. Outcome measures included EFS, time to engraftment, and cumulative incidence of GVHD (CIN of GVHD) for MSD and MUD cohorts. EFS and stable engraftment rate were 100%. CIN of acute GVHD was: MSD, Grade I–II: 1 (11%), Grade III–IV: 0%; MUD, Grade I–II: 1 (20%), Grade III–IV: 1 (20%). CIN of chronic GVHD was: MSD, limited: 1 (11%), extensive: 0%; MUD, limited: 0%, extensive: 0%. All immunosuppressive‐compliant patients successfully weaned immunosuppression. Although in limited patients, our results suggest that immunomodulatory TLI added to backbone CTX/ATG conditioning is a promising option for MUD HCT in SAA patients, which we will examine in a prospective clinical trial.