Dr. Hurvitz on Progress Made With Antibody-Drug Conjugates in HER2+ Breast Cancer

Sara A. Hurvitz, MD, associate professor, David Geffen School of Medicine, University of California, Los Angeles (UCLA), medical oncologist, medical director, Jonsson Comprehensive Cancer Center Clinical Research Unit, co-director, Santa Monica-UCLA Outpatient Oncology Practices, director, Breast Cancer Clinical Trials Program, UCLA, discusses progress made in 2021 with antibody-drug conjugates (ADCs) in HER2-positive breast cancer.

During the 2021 ESMO Congress, interim findings from the phase 3 DESTINY-Breast03 trial (NCT03529110) were presented. The results showed that fam-trastuzumab deruxtecan-nxki (Enhertu) improved progression-free survival (PFS) compared with ado-trastuzumab emtansine (T-DM1; Kadcyla) in patients with metastatic HER2-positive breast cancer. Notably, these results were practice changing because they supported the use of trastuzumab deruxtecan vs T-DM1 in the second-line setting for this patient population.

Additionally, findings from the phase 3 TULIP trial (NCT03262935), which were also presented during the 2021 ESMO Congress, demonstrated an improvement in PFS with vic-trastuzumab duocarmazine (SYD985) vs physician’s choice of treatment in patients with metastatic HER2-positive breast cancer who received 2 prior regimens or T-DM1 in the metastatic setting.

Regarding safety with trastuzumab duocarmazine, ocular toxicities were observed as the most prevalent safety event, Hurvitz explains. As such, further research is needed to determine the severity of the ocular toxicities and how to best manage these events in this clinic, Hurvitz says.

In addition to these data regarding ADCs, data from phase 1 studies evaluating novel ADCs are also coming to light, so this will be a continually evolving field in 2022, Hurvitz concludes.