Donor Lymphocyte Infusion in the Treatment of First Hematological Relapse After Allogeneic Stem-Cell Transplantation in Adults With Acute Myeloid Leukemia: A Retrospective Risk Factors Analysis and Comparison With Other Strategies by the EBMT Acute Leukemia Working Party

Purpose To evaluate the role of donor lymphocyte infusion (DLI) in the treatment of relapsed acute myeloid leukemia (AML) after allogeneic hematopoietic stem cell transplantation (HSCT). Patients and Methods We retrospectively analyzed the data of 399 patients with AML in first hematological relapse after HSCT whose treatment did (n = 171) or did not (n = 228) include DLI. After correction for imbalances and established risk factors, the two groups were compared with respect to overall survival. Further, a detailed analysis of risk factors for survival among DLI recipients was performed. Results Median follow-up was 27 and 40 months, respectively. Estimated survival at 2 years (± standard deviation) was 21% ± 3% for patients receiving DLI and 9% ± 2% for patients not receiving DLI. After adjustment for differences between the groups, better outcome was associated with age younger than 37 years (P = .008), relapse occurring more than 5 months after HSCT (P < .0001), and use of DLI (P = .04). Among DLI recipients, a lower tumor burden at relapse (< 35% of bone marrow blasts; P = .006), female sex (P = .02), favorable cytogenetics (P = .004), and remission at time of DLI (P < .0001) were predictive for survival in a multivariate analysis. Two-year survival was 56% ± 10%, if DLI was performed in remission or with favorable karyotype, and 15% ± 3% if DLI was given in aplasia or with active disease. Conclusion Although further evidence for a graft-versus-leukemia effect by DLI is provided, our results confirm, that the clinical benefit is limited to a minority of patients. Strategies to reduce tumor burden before DLI, as well as alternative treatment options should be investigated in adults with relapsed AML after HSCT.