NEW YORK – Roche announced on Friday that its Pathway Anti-HER2/neu (4B5) Rabbit Monoclonal Primary Antibody has received a label expansion from the US Food and Drug Administration as a companion diagnostic for Daiichi Sankyo and AstraZeneca's Enhertu (trastuzumab deruxtecan).
The test can now be used to identify a new metastatic breast cancer patient population designated as HER2-ultralow, which refers to patients who have very low levels of HER2 expression. Before 2022, patients were categorized as HER2-positive or HER2-negative based on the level of HER2 expression, and in 2022 the designation of HER2-low status was introduced. Patients with HER2-ultralow status have even lower levels of expression than HER2-low, Roche noted in a statement.
The Pathway HER2 test was approved as a companion diagnostic for assessing HER2-low status in 2022.
Enhertu received FDA approval for previously treated patients with unresectable or metastatic hormone receptor (HR)-positive, HER2-low or HER2-ultralow breast cancer earlier this week. The drug was used in the DESTINY-Breast06 trial to treat HER2-low and HER2-ultralow metastatic breast cancer patients.
"The rising incidence of metastatic breast cancer, particularly among younger populations, underscores the urgent need for new diagnostic options," Roche Diagnostics CEO Matt Sause said in a statement. "The approval of our test for determining HER2-ultralow status offers new hope to patients by providing a possible path to HER2-targeted treatment where none existed before, helping clinicians transform outcomes for many facing this challenging disease."
The assay is used in combination with Roche's BenchMark IHC/ISH slide staining instrument and standardizes all immunohistochemistry processes from baking through staining.