Roche on Wednesday announced that it has received the CE Mark for the first companion diagnostic (CDx) test to identify patients with HER2-low metastatic breast cancer who may be eligible for treatment with Enhertu.
Enhertu (trastuzumab deruxtecan), jointly developed and commercialized by Daiichi Sankyo and AstraZeneca, is a HER2-directed antibody drug conjugate.
Roche's Ventana HER2 (4B5) Rabbit Monoclonal Primary Antibody RxDx test is the first, and thus far only, CDx test approved to aid in the assessment of metastatic breast cancer patients who may be eligible for treatment with the HER2-targeted treatment, which could significantly improve their outcome.
Typically, if a patient's tumor expresses high levels of HER2, the patient is identified as HER2-positive and may be considered eligible for HER2-targeted treatment. However, half of all patients with metastatic breast cancer express low levels of HER2, which historically has classified them as HER2-negative.
The Roche CDx test now includes a scoring algorithm that helps identify these "low expressors" of HER2, assigning a HER2-low status to this patient group. The lower cutoff allows the assay to identify patients who may benefit from Enhertu, Roche said in a statement.
The Roche test, which is marketed under the brand name Pathway in the U.S., received U.S. Food and Drug Administration approval in October 2022.
