Prophylactic donor lymphocyte infusion after haploidentical hematopoietic cell transplantation and post‐transplant cyclophosphamide for treatment of high‐risk myeloid neoplasms in children: A retrospective study

Abstract

AbstractBackgroundPost‐transplant cyclophosphamide (PTCy) has been recommended for prevention of graft‐versus‐host disease (GvHD) following haploidentical hematopoietic cell transplantation (haplo‐HCT) for treatment of malignant blood diseases, but disease relapse remains a problem. Although donor lymphocyte infusion (DLI) is reported to be effective for treating post‐transplantation relapse, the efficacy and safety of prophylactic‐DLI (pro‐DLI) post haplo‐HCT, and PTCy in pediatric patients with hematological malignancies is unknown.MethodsWe retrospectively analyzed the outcomes of 54 pediatric patients with high‐risk myeloid neoplasms who received a PTCy regimen for GvHD prophylaxis and pro‐DLI after haploidentical peripheral blood stem cell transplantation. The high‐risk myeloid neoplasms in this cohort included acute myeloid leukemia (n = 46) and myelodysplastic syndromes (n = 8).ResultsMedian follow‐up was for 19.7 (range: 3.4–46.6) months. The cumulative incidences of grade II–IV and III–IV acute GvHD were 37.0% (95% CI: 22.7%–48.7%) and 16.7% (95% CI: 6.1%–26.0%), respectively. There were no graft‐failure events, and the 2‐year rate of moderate/severe chronic GvHD was 8.1% (95% CI: 0%–16.7%). The 2‐year non‐relapse mortality, relapse, disease‐free survival, GvHD‐free relapse‐free survival, and overall survival rates were 5.1% (95% CI: 0%–11.7%), 16.6% (95% CI: 5.3%–26.6%), 78.9% (95% CI: 68.0%–91.6%), 62.2% (95% CI: 49.4%–78.3%), and 87.3% (95% CI: 78.3%–97.4%), respectively.ConclusionsProphylactic donor lymphocyte infusion in the setting of haploidentical hematopoietic cell transplantation with post‐transplant cyclophosphamide appears to be effective and safe in pediatric patients with high‐risk myeloid neoplasms.