Outcomes with Preemptive Donor Lymphocyte Infusions after Allogeneic Hematopoietic Stem Cell Transplantation for Acute Myeloid Leukemia and Myelodysplastic Syndromes: A Systematic Review and Meta-Analysis.

e19014 Background: Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative therapy for acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) but relapse and graft versus host disease (GVHD) remain the most common challenges. Donor lymphocyte infusion (DLI) is the infusion in which lymphocytes from the original stem cell donor are infused, after the transplant, to augment an anti-tumor response or to ensure that the donor stem cells remain engrafted. In this systematic review and meta-analysis, we focused at outcomes of preemptive DLI in AML and MDS. Methods: Following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines (PRISMA) PubMed, CINAHL, Cochrane, and Clinical trials.gov were searched. We included 8 out of 214 articles, excluding duplicates and non-relevant articles. The quality of the included studies was evaluated using NIH quality assessment tool. Proportions along with 95% Confidence Interval (CI) were extracted to compute pooled analysis using the ‘meta’ package by Schwarzer et al. in the R programming language (version 4.16-2) to report the efficacy of preemptive DLI. We pooled the experimental arms results of the included trials using the inverse variance method and logit transformation. Between studies, the variance was calculated using Der Simonian-Laird Estimator. Results: We identified 222 patients who received preemptive DLI. Median age, time since transplant and DLI dose were 48 (32-58) years, 82 (7-160) days and 1.4 million cells/kg respectively. CR and PR were 43% (95%CI 0.14-0.78, I293%, n= 127) and 61% (95%CI 0.40-0.78, I262%, n= 81) respectively. After median follow up of 46 months, non-relapsed mortality (NRM) was 52% (95%CI 0.38-0.65, I249%, n = 121). OS was reported 72% (95%CI 0.62-0.80, I20%, n= 100). Acute and chronic GVHD incidence after DLI was 20% (95% CI 0.13-0.29, I24%, n= 105) and 25% (95% CI 0.08-0.56, I2=79%, n=101) respectively (Table). Conclusions: Preemptive DLI significantly improves OS with a low incidence of acute and chronic GVHD. However, NRM was seen in more than half of all the patients and prospective studies are needed to evaluate safety of preemptive DLI. Outcomes with preemptive DLI (n= 222).[Table: see text]