Autologous or Allogeneic Hematopoietic Stem Cell Transplantation as Front-Line Treatment for Adult Secondary Acute Myeloid Leukemia Patients: The PETHEMA Registry Experience

It is widely accepted that allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the sole potentially curative option available for secondary acute myeloid leukemia (sAML). However, clinical factors impacting outcomes after allo-HSCT and the potential role of autologous HSCT (auto-HSCT) in real-life series are needed. Previously, the PETHEMA group reported a series of 2310 patients with sAML in the nationwide registry. Of these, 876 were candidates to receive chemotherapy and 274 underwent HSCT (55 auto-HSCT and 219 allo-HSCT). In this study, we analyzed the role of auto-HSCT or allo-HSCT as front-line treatment for sAML patients included in the Spanish PETHEMA AML registry. Here we report an analysis of outcomes as well as prognostic variables in this series of patients undergoing auto-HSCT or allo-HSCT as part of the front-line treatment for sAML. We used the multinational PETHEMA AML registry (Clincial Trials.gov identifier NCT02607059) to identify adult patients (age ≥18 years) with a diagnosis of sAML who underwent auto- or allo-HSCT as front-line treatment in Spanish and Portuguese institutions between August, 1, 1992, and July, 31, 2020. Patient characteristics, diagnostic findings, and management, including treatments, characteristics of HSCT, and outcomes, were retrieved from the PETHEMA AML registry in this retrospective multicenter analysis. With a median follow-up of 32.7 months, better 5-year overall survival (OS) and leukemia-free survival (LFS) were obtained with allo-HSCT in first complete response (CR) (44.5% and 39.9%, respectively) compared with auto-HSCT in CR1 (30% and 20.5%, respectively) but without reaching statistical differences for OS (P = .22 and .03, respectively). The higher incidence of relapse in auto-HSCT is counterbalanced with the significantly lower nonrelapse mortality rate. For allo-HSCT recipients, 5-year outcomes were significantly influenced by the cytogenetic/genetic risk. In multivariate analysis, the adverse cytogenetic/genetic risk group retained statistical significance for all endpoints. We confirmed the role of allo-HSCT as a potential curative option for patients and report that auto-HSCT in CR can still provide a 5-year LFS of 20% in sAML patients. Finally, our results confirm adverse cytogenetic/genetic risk category as an independent negative factor in sAML patients undergoing HSCT.