Dr. Hart on Antibody-Drug Conjugates in HER2+ Breast Cancer

Lowell L. Hart, MD, FACP, scientific director of Clinical Research at Florida Cancer Specialists & Research Institute, and associate professor of Internal Medicine at Wake Forest School of Medicine, discusses the utility of antibody-drug conjugates (ADCs) in HER2-positive breast cancer.

In February 2013, ado-trastuzumab emtansine (T-DM1; Kadcyla) was approved to treat patients with metastatic HER2-positive breast cancer who had previously received trastuzumab (Herceptin) and a taxane. The label was updated in May 2019 to include use as adjuvant treatment in patients with HER2-positive early breast cancer who have residual invasive disease after neoadjuvant chemotherapy and trastuzumab (Herceptin)-based treatment.

Historically, patients with residual disease at the time of surgery continued on trastuzumab for the remainder of a year. Now, patients are given T-DM1 rather than trastuzumab according to data from the phase III KATHERINE trial, explains Hart.

Another ADC, trastuzumab deruxtecan (T-DXd; DS-8201), demonstrated an objective response rate of approximately 61% in patients with heavily pretreated advanced disease in the randomized phase II DESTINY-Breast01 trial. Data from the trial were presented at the 2019 San Antonio Breast Cancer Symposium. T-DXd has a higher drug to antibody ratio and a different payload than T-DM1, concludes Hart.