Can Posttransplant Cycloposphamide Reduce the Risk of Graft vs Host Disease for Pediatric Fully Matched Non-Related Stem Cell Transplantation?

Abstract

Abstract Objective Post-transplant cyclophosphamide (postCy) is widely used as prophylaxis for graft-versus-host disease (GvHD) in haploidentical bone marrow transplantation and is being investigated in matched transplants for pediatric patients. The effect of postCy for prophylaxis of GvHD in pediatric, fully-matched, unrelated, peripheral blood stem cell transplantation (PBSCT) is described. Methods This was a retrospective clinical study of 110 pediatric patients diagnosed with malignant and non-malignant diseases who underwent PBSCT from matched unrelated donors (MUD). Fifty patients received 50 mg/kg/d cyclophosphamide on day +3 and +4, designated Group 1, while the remaining 60 (Group 2) did not receive postCy. All patients were given a regimen of standard immunosuppression. Results One hundred and ten patients younger than 18 years (73 males and 37 females) were followed-up for a median of two years after successful PBSCT. The incidence of grade II–IV and grade III–IV acute GvHD was 28% and 18% in Group 2 while in Group 1 these rates were 20% and 10%, respectively. The incidence of chronic GvHD was 8.3% for Group 2 and 4% in Group 1. Survival for >100 days was 87.2% overall, 86% in Group 1 and 89% in Group 2; similarly, overall survival in these three populations was 78%, 76% and 80%, respectively. None of these differences were significant. Conclusion Although postCy-transplant was shown to have advantages for unmatched and haploidentical PBSCT in adult patients, the findings of the present study suggest no effect in fully MUD PBSCT in children. There is a need for larger studies to confirm or refute these findings and, if shown to be robust, to investigate why there is this difference between pediatric and adult transplant patients.