Dr. Shiller on the Role of Trastuzumab Deruxtecan in HER2+ Breast Cancer

Michelle Shiller, DO, AP/CP, MGP, member, the Precision Medicine Institute's Advisory Committee, Baylor University Medical Center, discusses the role of fam-trastuzumab deruxtecan-nxki (Enhertu) in patients with HER2-positive breast cancer.

In May 2022, the FDA granted regular approval to trastuzumab deruxtecan for adult patients with unresectable or metastatic HER2-positive breast cancer who have previously received an anti–HER2-based regimen either in the metastatic setting, or in the neoadjuvant or adjuvant setting, and have developed disease recurrence during or within 6 months of therapy completion.

Although HER2 has long been an important biomarker in breast cancer, a deeper understanding of the biomarker is important as new agents continue to emerge, Shiller says. Data from the phase 3 DESTINY-Breast02 (NCT03523585) and DESTINY-Breast03 (NCT03529110) trials have shown that patients who historically have had good responses with trastuzumab (Herceptin) can derive a greater benefit with trastuzumab deruxtecan, Shiller adds.

HER2-positive disease is defined as HER2 overexpression of 3+ with immunohistochemistry (IHC) or HER2 amplification of 2+ with IHC/ fluorescence in situ hybridization assays. These standards are used to identify patients who can benefit from HER2-targeted therapies, Shiller concludes.