Efficacy of allogeneic hematopoietic stem cell transplantation with cocktail conditioning regimen for the treatment of pediatric patients with chronic active Epstein-Barr virus: A retrospective observational study.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) was considered as an only therapeutic strategy for chronic active Epstein-Barr virus (CAEBV) infection with few exceptions, while efficacy of various allo-HSCT conditioning regimens for CAEBV has not been fully investigated yet. This study aimed to compare the effectiveness of cocktail conditioning regimen (CCR)-allo-HSCT with reduced-intensity conditioning regimen (RICR)-allo-HSCT for pediatric patients with CAEBV. Data of a total of 54 children with CAEBV from July 2015 to December 2020, were retrospectively analyzed. Among them, 32 patients received VP16, total body irradiation (TBI), busulfan, fludarabine, cyclophosphamide, and anti-thymocyte globulin (ATG) (CCR1 group), 10 patients received VP16, ara-C, TBI, busulfan, fludarabine, cyclophosphamide, and ATG (CCR2 group), and the remaining 12 patients received VP16, busulfan or melphalan, fludarabine, and ATG with or without ara-C (RICR group). The overall survival (OS), hematopoietic engraftment, the incidence of severe graft-versus-host disease (GVHD), and other parameters were analyzed. After adjusting for potential confounders, CCR1 (hazard ratio (HR): 0.023; 95% confidence interval (CI): 0.001-0.448; P=0.013) and CCR2 (HR: 0.028; 95%CI: 0.002-0.457; P=0.012) were associated with a longer OS than RICR. The use of CCR could markedly improve the engraftment success rate and OS rate compared with RICR for pediatric patients with CAEBV.