Roche’s breast cancer companion diagnostic receives CE Mark

Roche has received the CE Mark for the first companion diagnostic test to identify patients with HER2-low metastatic breast cancer who may be eligible for Enhertu, a type of targeted cancer drug.

Enhertu (trastuzumab deruxtecan), jointly developed and commercialised 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, companion diagnostic test approved to aid in the assessment of metastatic breast cancer patients who may be eligible for treatment with Enhertu, which could significantly improve their outcome.

The test, which is branded PATHWAY in the US, received US Food and Drug Administration (FDA) approval in October 2022.

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.

According to Roche, the VENTANA HER2 (4B5) test includes a scoring algorithm that helps pathologists to identify “low expressors” of HER2, assigning a HER2 low status to this group of patients. With this lower cutoff, the test could identify patients who may benefit from Enhertu as a treatment option.

Breast cancer has surpassed lung cancer as the most commonly diagnosed cancer, with more than two million new cases diagnosed worldwide each year. More than 685,000 people die from breast cancer every year.

Jill German, head of pathology lab at Roche Diagnostics, said: “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.

“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.”