1088P - Impact of donor lymphocyte infusion in relapsing myeloid neoplasms post allogeneic hematopoietic stem cell transplantation

Abstract

BackgroundDonor lymphocyte infusions (DLI) become one of the currently used approaches to treat post-transplant relapses. However, the wide use of the different DLI strategies, its effectivity and toxicity are still unpredictable in many patients. We evaluated the impact of DLI for patients with myeloid neoplasms experienced relapse post hematopoietic stem cell transplantation (HSCT). MethodsThis study included patients with myeloid neoplasms who received DLI post HSCT at the BMT unit, Children Cancer Hospital Egypt (CCHE-57357) from 2009 to 2017. DLI was given for patients with either rising minimal residual disease (MRD) or after systemic chemotherapy for those who experienced frank relapse. ResultsA total of 20 patients received post HSCT DLI were analyzed, with median age of 7 years. About 12 patients (60%) had acute myeloid leukemia (AML), 5 with chronic myeloid leukemia (CML) and 3 cases had myelodysplastic syndrome (MDS). Seven patients had frank relapse and given systemic chemotherapy followed by DLI upon complete remission, while 13 patients received only DLI due to rising MRD. Early relapse (during 1st year) was reported in 14 cases (70%) and 7 patients relapsed beyond 1st year post-transplant. Regarding the graft status at relapse, 15 patients had maintained complete chimera while 5 patients showed mixed chimera. The one-year disease free survival (DFS) and overall survival (OS) post DLI for the whole cohort were 54% and 64%, respectively with one patient had a non-relapse mortality and 6 patients developed graft versus host disease (GvHD) post DLI. According the initial diagnosis, DFS at one year was 80% for CML, 66% for MDS and 41% for AML patients. Also DFS was better for those with late relapse (70% vs 57% for early relapse) and for those who developed GvHD post DLI. ConclusionsDLI was associated with a durable efficacy and low toxicity in pediatric patients with hematologic malignancies. However, larger studies and standardized approaches are required to identify the outcome predictors of this treatment modality. Legal entity responsible for the studyThe authors. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.