Dr. Hurvitz on the Lack of Predictive Biomarkers in HER2+ Breast Cancer

Sara A. Hurvitz, MD, associate professor at the David Geffen School of Medicine, University of California, Los Angeles (UCLA) medical director of the Jonsson Comprehensive Cancer Center Clinical Research Unit, co-director of the Santa Monica-UCLA Outpatient Oncology Practices, and director, Breast Cancer Clinical Trials Program, UCLA, discusses the lack of predictive biomarkers in HER2-positive breast cancer.

Biomarkers such as tumor-infiltrating lymphocytes, PD-L1 expression, hormone receptor (HR) co-expression, and PIK3CA mutations have been evaluated in HER2-positive breast cancer, explains Hurvitz.

However, no biomarkers have emerged that can determine whether a patient is likely to respond to HER2-targeted therapy, Hurvitz says.

Factors such as nodal status and HR co-expression are used to determine which therapies should be given in addition to trastuzumab, says Hurvitz.

Moreover, during the 2020 ASCO Virtual Scientific Program, biomarker analyses from the phase 3 KATHERINE study revealed that patients responded to adjuvant ado-trastuzumab emtansine (Kadcyla; T-DM1), irrespective of HR status, PIK3CA mutational status, nodal status, or burden of residual disease at the time of surgery, Hurvitz concludes.