- Roche has received approval from the Food and Drug Administration for the first companion diagnostic to identify patients with so-called HER2-low breast cancer.
- U.S. officials first authorized the test in 2000 to help identify HER2-positive breast cancer patients. Now, Roche has added a scoring algorithm to help pathologists identify patients whose tumors express low, but still detectable levels of the protein.
- The approval of Roche’s test comes two months after AstraZeneca and Daiichi Sankyo’s Enhertu became the first therapy in the U.S. authorized to treat HER2-low breast cancer.
About 80% to 85% of the 287,850 new breast cancer cases estimated to occur in the U.S. this year would previously have been considered HER2-negative. Now, a majority of them will be regarded as HER2-low patients, according to the FDA. The distinction, and the ability to find patients with HER2-low tumors, is important because of Enhertu’s recent approval.
Study results showing that Enhertu nearly cut in half the risk of disease progression or death in trial volunteers with HER2-low breast cancer paved the way for the treatment to become the first targeted therapy available to that group of patients.
“Previously, metastatic breast cancer patients with a lower level of HER2 expression were considered to be part of the HER2-negative population and had no HER2-targeted treatment options. Now, they may be eligible for a HER2-targeted therapy, significantly increasing the number of patients who could have improved outcomes,” Thomas Schinecker, CEO of Roche Diagnostics, said in a statement.
Roche’s approval provides physicians with a new way to determine if a patient should receive Enhertu. AstraZeneca and Daiichi used the test to identify patients with low levels of HER2 and thereby determine if an individual was eligible to participate in their trial.
The identification of HER2-low breast cancer patients is enabled by a new scoring algorithm. Using the algorithm, pathologists can identify “low expressors” of HER2 who meet the criteria for treatment with Enhertu.