Allogeneic Hematopoietic Stem Cell Transplantation for Elderly Acute Lymphoblastic Leukemia Patients: A Registry Study From the Société Francophone de Greffe de Moelle et Thérapie Cellulaire (SFGM-TC).

There are very limited data regarding the outcomes of elderly patients with acute lymphoblastic leukemia (ALL) who undergo allogeneic hematopoietic stem cell transplantation (alloHSCT). A total of 316 ALL patients aged ≥ 60 years who underwent alloHSCT between 2010 to 2022 were identified in the SFGM-TC registry. The primary objective was to evaluate progression-free survival (PFS), non-relapse mortality (NRM), relapse incidence (RI), and graft-versus-host disease (GvHD)-free relapse-free survival (GRFS), as well as their risk factors. The median age was 63.8 years (range 60-75.8), 49.8% of patients had Philadelphia-positive B-ALL (Ph + ALL), and 70.9% were in first complete remission (CR1) at transplantation. The donor was an unrelated donor in 52.1%, a matched related donor (MRD) in 26.3%, and a haplo-identical donor in 17.7%. Reduced-intensity conditioning (RIC) was administered to 64.6% of patients, while total body irradiation (TBI) was used in 35.8%. The 3-year overall survival (OS) was 46% (95% CI 40%-53%). The 3-year PFS, NRM, RI, and GRFS were 41% (95% CI 35%-48%), 23% (95% CI 18%-28%), 36% (95% CI 31%-42%), and 30% (95% CI 25%-37%), respectively. Multivariable analyses confirmed poorer OS and PFS in patients with advanced disease, with an HR of 1.79 (95% CI 1.22-2.64), p = 0.0032. Additionally, the ALL subtype significantly impacted outcomes, with an HR of 1.99 (95% CI 1.42-2.79) for non-Ph + ALL. This study suggests that alloHSCT is a viable option for elderly ALL patients, as age itself did not impact outcomes. However, advanced disease and non-Ph + ALL were associated with significantly worse survival.