Allo-HCT refined ELN 2022 risk classification: validation of the Adverse-Plus risk group in AML patients undergoing allogeneic hematopoietic cell transplantation within the Spanish Group for Hematopoietic Cell Transplantation (GETH-TC).

This multicenter retrospective study by GETH-TC validates the prognostic value of the Allo-HCT Refined ELN 2022 risk classification in allografted AML patients. The new classification refines the ELN 2022 risk classification, dividing adverse-risk patients into two subgroups: Adv-Plus (AdvP), including those with complex karyotype, MECOM (EVI1) rearrangement, or TP53 mutations/del(17p), and an additional adverse group (Adv*). The study included 651 AML patients treated with at least one line of anthracycline-based induction therapy and in complete remission. According to the Allo-HCT Refined ELN 2022 risk classification, 19.4% (n = 126) patients were classified into the Favorable (Fav) risk, 38.1% (n = 248) into the Intermediate (Int) risk, 27.2% (n = 177) in the Adv* and 15.4% (n = 100) in the AdvP. Outcomes were significantly poorer for patients allocated in the AdvP risk group (5-year OS rate: 32.3%, 5-year LFS rate: 24.3%, both p < 0.001 with the rest of subgroups) and a higher CIR (5-year CIR: 64.3%, p < 0.001). Patients in the Adv* risk group had similar outcomes than patients in the Int risk group (5-year OS rate: 70.2% vs. 66.7%, p = 0.69, 5-year LFS rate: 63.8% vs. 55.9%, p = 0.33). Multivariate analysis confirmed the dismal outcomes for AdvP patients for OS: Hazard Ratio (HR) = 3.05, and LFS: HR = 2.66, both p < 0.001. Our findings validate the Allo-HCT Refined ELN 2022 classification as a robust prognostic tool, particularly highlighting the poor outcomes for the AdvP subgroup.