Is the Revised ELN Classification More Accurate for Acute Myeloid Leukemia?

The revised 2017 European LeukemiaNet (ELN) classification (ELN‐2017) of acute myeloid leukemia (AML) appears to much more accurately distinguish prognosis in younger patients with newly diagnosed AML compared with ELN-2010, according to a new study published in Cancer. However, the prognostic significance of the FMS‐like tyrosine kinase 3 (FLT3)–internal tandem duplication (ITD) allele ratio (AR) (FLT3‐IT AR) needs further evaluation in different treatment settings.

ELN‐2017 classifies patients into one of three prognostic risk categories and assigns other risk stratification factors, such as the FLT3‐IT AR. Prajwal C. Boddu, of The University of Texas MD Anderson Cancer Center in Houston, and colleagues conducted a retrospective study on patients aged younger than 60 years who received idarubicin plus cytarabine (IA)–based induction chemotherapy for newly diagnosed AML.

When employing ELN‐2017 criteria, 27% of the patients were in the favorable risk category (n = 192), 46% were in the intermediate risk category (n = 331), and 27% were in the adverse risk category (n = 192). The researchers found that overall survival probabilities at 5 years were 57% in the favorable risk group, 37% in the intermediate group, and 18% in the adverse risk group.

When the team looked at the ELN‐2010 criteria, they found several differences. The 5‐year overall survival probabilities in the favorable group were 59% (n = 169). The overall survival probabilities were 32% in the intermediate group-1 (n = 80), 40% in intermediate group-2 (n = 306), and 14% in the adverse group (n = 160).

ELN‐2010 historically had distinguished prognosis into the intermediate‐1 and intermediate‐2 categories in younger patients. However, this difference was nullified in the current study cohort. When the researchers looked at patients with a low FLT3‐ITD AR compared with a high FLT3‐ITD AR, they found no significant differences in survival among patients with nucleophosmin 1 (NPM1) –mutated AML (P = .28) or wild‐type NPM1 (P = .35), and in those treated with IA alone (P = .79). The same was true for patients treated with IA and an FLT3 inhibitor (P = .10).

In an interview with Cancer Network, Prapti Patel, MD, an assistant professor of internal medicine at UT Southwestern Medical Center in Dallas, said these findings are of significant interest because they may impact future clinical trial design. Patel said these findings also are relevant because they better inform clinicians on treatment decisions. “It is important to look at this because it helps us decide if patients are going to respond. These risk groups are really important because they predict response and relapse rates in the future,” said Patel.