ELN 2017 Risk Classification Predicts Survival of AML Patients Receiving Allogeneic Hematopoietic Stem Cell Transplantation

Abstract

European LeukemiaNet (ELN) 2017 updated prognostic system for acute myeloid leukemia (AML), which incorporates both cytogenetic and molecular risks, stratifying patients into 3 distinct genetic risk groups: favorable, intermediate and adverse. While most patients in favorable risk group can be cured with chemotherapy alone, the majority of patients in intermediate and adverse genetic risk groups are considered for curative allogeneic hematopoietic stem cell transplantation (alloHCT). However, the impact of ELN 2017 risk classification on survival of AML patients after alloHCT remains unclear. We examined the prognostic significance of ELN 2017 classification on 503 AML patients in first or second complete remission (373 CR1/ 130 CR2) receiving alloHCT at Moffitt Cancer Center) from 2005-2016. Patients were classified into favorable (n=58, 11.6%), intermediate (n=284, 56.8%) and adverse (n=158, 31.6%) ELN risk groups. The median age at alloHCT for the entire cohort was 55 years (range, 18-76 years) and 29% of all patients had many comorbidities (HCT ≥3) at transplant. Disease risk index (DRI) was low in 38 (7.6%), intermediate in 393 (78.6%) and high in 69 (13.8%) patients, and 22% (n=109) of all patients had secondary AML. Myeloablative conditioning was used in 77% (n=389) of patients, while 23% (n=114) received reduced-intensity conditioning regimen. HLA-matched unrelated donor (47%) was the most commonly used donor type, followed by matched related (27.7%) and mismatched donors (n=75, 9.8%). For the entire cohort, 2-year overall survival (OS) was 56% (52-60%) and leukemia-free survival (LFS) was 51% (47-55%). Patients with CR1 and CR2 status at alloHCT had similar OS (58% vs. 53%, p=0.17). We identified that ELN 2017 genetic risk is prognostic of OS after alloHCT in patients with AML: 72% (61-84%) in favorable risk vs. 60% (54-66%) in intermediate risk vs. 45% (38-53%) in adverse risk groups (p Our findings highlight the prognostic impact of ELN 2017 genetic risk on survival of AML patients undergoing alloHCT in CR1/CR2. Patients in the adverse risk group had higher risk of relapse and worse survival. Thus, ELN 2017 prognostic system can help identify AML patients in CR1/CR2 who can benefit from clinical trials offering relapse reduction strategies in order to improve their survival.