EHA/ELN guidance on blast reporting in acute leukemias

Representatives from the European Hematology Association (EHA) and European LeukemiaNet (ELN) produced consensus guidance on harmonized blast assessment to define response categories in patients with acute leukemia, published by Wang et al. in Haematologica. 

Key data: The panel recommends measurable residual disease (MRD) assays replace morphology as the gold standard to assess bone marrow remission in acute lymphoblastic leukemia (ALL), with minimum validated sensitivity of 0.01%. Morphological blast count ≥5% does not define persistent disease or relapse unless confirmed by appropriate MRD assay. In acute myeloid leukemia (AML), it is strongly recommended to perform MRD using an appropriate assay with a minimum validated threshold of 0.1%. Morphological blast count ≥5% does not define persistent disease or relapse if the MRD assay or other diagnostic test for genetic abnormalities in AML and high-risk myelodysplastic syndrome (MDS) is negative. 

Key learning: Establishing standardized criteria and implementing internationally harmonized procedures are crucial for ensuring uniform response and relapse assessment in acute leukemias. These harmonized criteria should improve the consistency and quality of this data entry across clinical trials and broader clinical practice.