Post‐transplant сyclophosphamide after matched donor hematopoietic stem cell transplantation in children with acute leukemia

Abstract

AbstractIntroductionThe data on post‐transplant cyclophosphamide (PTCy) in pediatric acute leukemia after matched allo‐HSCT are limited to case series. The present study aimed to assess the results of PTCy‐based GVHD prophylaxis in a large cohort of children with acute leukemia after matched allo‐HSCT.MethodsA retrospective analysis of 190 pediatric patients with acute leukemia who had a first allograft between 2008 and 2020 from a matched sibling donor (MSD) or matched unrelated donor (MUD) was carried out. In the MSD setting, GVHD prophylaxis consisted of PTCy alone (n = 28) for the study group, and calcineurin inhibitor (CNI) ± antimetabolite (n = 30) for the control group. In MUD setting, most patients in the study group received GVHD prophylaxis with PTCy+CNI+mycophenolate mofetil (n = 42, 66.7%) or PTCy+CNI+sirolimus (n = 12, 19%). All patients (n = 69) in the control group received ATG+CNI+antimetabolite.ResultsAfter MUD allo‐HSCT, the incidences of acute GVHD grade III‐IV and moderate/severe chronic GVHD were significantly lower in the PTCy group compared to control (6.6% vs. 35.0% and 12.7% vs. 47.1%, respectively, p < .0001). Five‐year GVHD‐free, relapse‐free survival (GRFS) after MUD allo‐HSCT was higher in the PTCy group compared to control (35.1% vs. 7.3%, p < .0001). At the same time, there was no significant difference between both groups after MSD allo‐HSCT.ConclusionsIn pediatric acute leukemia, PTCy‐based GVHD prophylaxis for MUD allo‐HSCT is a feasible and effective option that results in a low incidence of GVHD. Compared to the ATG‐based approach, PTCy provides better control of GVHD in children. In pediatric allo‐HSCT from MSD, PTCy demonstrates comparable effectiveness to conventional GVHD prophylaxis.