Association of second allogeneic hematopoietic cell transplant vs donor lymphocyte infusion with overall survival in patients with acute myeloid leukemia relapse

IMPORTANCE The optimal treatment approach to patients with acutemyeloid leukemia (AML) who relapse after an allogeneic hematopoietic cell transplant (allo-HCT) remains elusive. No randomized clinical trial comparing survival outcomes of a second allo-HCT (allo-HCT2) vs donor lymphocyte infusion (DLI) has been conducted to date. OBJECTIVE To compare overall survival (OS) after an allo-HCT2 or DLI in relapsed AML after a first allo-HCT. DESIGN, SETTING, AND PARTICIPANTS A retrospective registry study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation involving 418 adults who received an allo-HCT2 (n = 137) or DLI (n = 281) for postallograft-relapsed AML. Analysis was assessed on the principle of intent-To-first received intervention. The data were collected from November 21, 2015, to May 15, 2017, and analysis was performed June 1, 2017. MAIN OUTCOMES AND MEASURES Number of patients with relapsed AML who are alive after 2 years and 5 years from receiving an allo-HCT2 or DLI. RESULTS Of the 418 patients, 228 (54.5%) were men; mean age was 46.2 years (interquartile range, 36.5-56.9 years). There was no apparent difference in OS whether an allo-HCT2 or DLI was prescribed (2-year OS with allo-HCT2, 26%; 5-year OS with allo-HCT2, 19%; 2-year OS with DLI, 25%; 5-year OS with DLI, 15%; P = .86). Overall survival was better if either of these procedures was offered when the patient was in complete remission (hazard ratio, 0.55; 95% CI, 0.41-0.74; P < .001). Conversely, OS was low for patients relapsing within less than 6 months after an allo-HCT1, regardless of the treatment prescribed (5-year OS: Allo-HCT2, 9%; 95%CI, 1%-17%vs DLI, 4%; 95%CI, 1%-8%; P = .86). CONCLUSION AND RELEVANCE Heterogeneity of the patient-, disease-, and treatment-related characteristics limit the ability to recommend one approach over another. Findings of this study highlight that best outcomes seem to be achieved in patients relapsing 6 or more months from an allo-HCT1 or those in complete remission at the time of either allo-HCT2 or DLI.