FDA Approves Roche’s PATHWAY HER2 Test for HER2-Ultralow Metastatic Breast Cancer

The FDA has approved a label expansion for Roche's PATHWAY anti-HER2/neu (4B5) Rabbit Monoclonal Primary Antibody test to identify patients with HR-positive, HER2-ultralow metastatic breast cancer57.

This test is now the first companion diagnostic approved to assess HER2-ultralow status in metastatic breast cancer patients, potentially making them eligible for treatment with Enhertu (trastuzumab deruxtecan)57.

Approximately 20-25% of hormone receptor-positive, HER2-negative breast cancer patients may be considered HER2-ultralow5.

The DESTINY-Breast06 trial showed that Enhertu improved median progression-free survival to 13.2 months compared to 8.1 months with standard chemotherapy in patients with HER2-low and HER2-ultralow metastatic breast cancer57.

This approval expands on the test's previous indication for HER2-low status, which was first approved in 202259.

The new HER2-ultralow classification represents patients with very low levels of HER2 expression, even lower than the existing HER2-low category57.

This advancement in HER2 diagnostics may provide new treatment options for patients who previously had limited targeted therapy options57.

The FDA has also approved Enhertu for the treatment of adult patients with unresectable or metastatic, hormone receptor-positive, HER2-low or HER2-ultralow breast cancer that has progressed on endocrine therapy in the metastatic setting4.

Sources:

4. https://www.onclive.com/view/fda-approves-trastuzumab-deruxtecan-for-pretreated-her2-low-and--ultralow-metastatic-breast-cancer

5. https://www.biospace.com/press-releases/roche-receives-fda-approval-for-the-first-companion-diagnostic-to-identify-patients-with-her2-ultralow-metastatic-breast-cancer-eligible-for-enhertu

7. https://www.roche.com/media/releases/med-cor-2025-01-31

9. https://diagnostics.roche.com/us/en/news-listing/2022/roche-receives-fda-approval-for-first-companion-diagnostic-to-id.html