Dr. Bhatt on the Investigation of Trastuzumab Deruxtecan in HER2-Low Breast Cancer

Ruchi Bhatt, DO, Jersey Shore University Medical Center, Ocean University Medical Center, Hackensack Meridian Health, discusses the investigation of fam-trastuzumab deruxtecan-nxki (Enhertu) in HER2-low breast cancer.

The phase 3 DESTINY-Breast04 trial (NCT03734029) compared the safety and efficacy of trastuzumab deruxtecan with physician's choice treatment in patients with HER2-low, unresectable or metastatic breast cancer who received 1 to 2 lines of prior chemotherapy in the metastatic setting.

Previously, HER2-targeted therapies were utilized for patients with HER2-positive breast cancer, classified as HER2 3+ with immunohistochemistry (IHC) or HER2 2+ with IHC and fluorescence in situ hybridization (FISH) assays, Bhatt says, adding that all other patients were considered HER2-negative. However, patients with HER2-low breast cancer, defined as HER2 1+ IHC or HER2 2+ IHC that is not FISH amplified, have emerged as another subgroup within the disease instead of being considered HER2-negative, Bhatt explains.

Defining HER2-low disease has allowed investigators to study targeted agents in new subsets of patients, Bhatt concludes.