Outcome of L-DEP Regimen for Treatment of Pediatric Chronic Active Epstein-Barr Virus Infection

Purpose We intended to investigate the clinical features of pediatric patients with chronic active Epstein-Barr virus infection (CAEBV) and effectiveness of the L-DEP regimen before HSCT (hematopoietic stem cell transplantation).Methods A retrospective analysis was performed on 35 patients with CAEBV at Beijing Children’s Hospital from January 2016 to January 2020. The efficacy and adverse events of the L-DEP regimen were evaluated.Results The median age of 35 patients was 7.0 years (range 2.5-17.5 years). 28 patients achieved clinical response (80.0%, 22 in clinical CR, 6 in clinical PR) after L-DEP. In terms of virological response, 7 patients (20%) were assessed as virological CR and 23 patients (65.7%) were virological PR. Finally, 29 patients underwent allo-HSCT. Median survival time was 18 months (2-50 months). The 3-year overall survival rates in patients treated with chemotherapy only (n=6), chemotherapy followed by HSCT (n=25) were 33.3% and 75.4%, respectively. After L-DEP 1st treatment, the amount of EBV-DNA loads in blood and plasma were significantly reduced than that before chemotherapy (median: 4.29×105 vs. 1.84×106, Mann-Whitney U：P=0.0004; 5.00×102 vs. 3.17×103, Mann-Whitney U：P=0.003). And, compared with liver and spleen size before chemotherapy, the size of liver and spleen shrank significantly after L-DEP 2nd (median 3.8cm vs. 1.9cm, P=0.003; 3.8cm vs. 0cm, P＜0.008). In addition, after L-DEP treatment, there was no difference in clinical or virological response rate whether HLH was accompanied or not (clinical response: 77.3% vs. 84.6%：P=0.689; virological response: 90.9% vs. 76.9%, P=0.337). Conclusion L-DEP regimen is an effective therapy in treating CAEBV for bridging to allo-HSCT.