New standards in HER2-low testing: the CASI-01 comparative methods study.

ABSTRACT:

Background

The introduction of Trastuzumab deruxtecan (T-Dxd) has exposed clinically significant limitations in accurately detecting HER2-low expression testing when using immunohistochemistry (IHC) assays originally developed to detect HER2 over-expression. While HER2 testing is widely used to determine T-Dxd eligibility, no HER2-low assay was ever validated against HER2 protein expression.

Methods

To address this pressing need, the Consortium for Analytic Standardization in Immunohistochemistry (CASI) conducted the CASI-01 study, involving 54 IHC laboratories across Europe and the U.S. The study aimed to identify optimal assay conditions for accurate HER2 testing, differentiating between HER2 overexpression (3+) for Trastuzumab eligibility and HER2-low expression (1+ or ul

SUBMITTER: Dabbs DJ 

PROVIDER: S-EPMC12571579 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature