Roche announced the approval of the CE Mark for the VENTANA HER2 (4B5) Rabbit Monoclonal Primary Antibody RxDx to identify metastatic breast cancer patients with low HER2 expression for whom ENHERTU (trastuzumab deruxtecan) may be considered as a targeted treatment.

The test, which is branded PATHWAY in the United States, received US Food and Drug Administration (FDA) approval in October 2022. ENHERTU is a specifically engineered HER2-directed antibody drug conjugate (ADC) being jointly developed and commercialised by Daiichi Sankyo and AstraZeneca.

HER2 is a receptor protein that helps cancer cells grow quickly. To determine a patient's HER2 status, pathologists evaluate, or score, the level of HER2 protein expressed in breast cancer tissue samples. If a patient's tumour expresses high levels of HER2, the patient is identified as HER2-positive and may be considered for HER2-targeted treatment. However, half of all patients with metastatic breast cancer express low levels of HER2 which historically classified them as HER2-negative.

"We are proud to continue our innovation in breast cancer diagnostics through critical tests like this one, which helps identify patients with HER2-low status," said Jill German, Head of Pathology Lab at Roche Diagnostics. "With this expanded approval of our test, we're pleased that more metastatic breast cancer patients across the world may be correctly identified and potentially eligible for this targeted therapy."