Ariella B. Hanker, PhD, of UT Southwestern Medical Center, discusses data showing that breast cancers expressing co-occurring HER2 and HER3 mutations may require the addition of a phosphoinositide 3-kinase alpha inhibitor to a HER2 tyrosine kinase inhibitor (Abstract GS6-04).
Hope S. Rugo, MD, of the University of California San Francisco Comprehensive Cancer Center, discusses trial data on margetuximab plus chemotherapy, which improved progression-free survival in patients with previously treated HER2-positive metastatic breast cancer when compared with trastuzumab plus chemotherapy. Maturing data comparing overall survival also provides new insights (Abstract GS1-02).
Ian E. Krop, MD, PhD, of Dana-Farber Cancer Institute, discusses phase II trial findings on trastuzumab deruxtecan, a HER2-targeting antibody-drug conjugate, in patients with HER2-positive metastatic breast cancer who were previously treated with trastuzumab emtansine (Abstract GS1-03).
Javier Cortes, MD, PhD, of the IOB Institute of Oncology, discusses study findings that suggested pembrolizumab offered a prolonged survival benefit compared to chemotherapy for a subset of patients with previously treated metastatic triple-negative breast cancer. In the trial, high tumor-infiltrating lymphocytes were significantly associated with better clinical outcomes with the checkpoint inhibitor.
Miguel Martín, MD, PhD, of the Gregorio Marañón Institute and GEICAM, discusses phase III study findings that showed no improvement in progression-free survival with palbociclib plus endocrine therapy vs capecitabine in patients with hormone receptor–positive/HER2-negative metastatic breast cancer whose disease progressed on aromatase inhibitors—although the drug combination was generally better tolerated than capecitabine (Abstract GS2-07).
Marie-Jeanne T.F.D. Vrancken Peeters, MD, PhD, of the Netherlands Cancer Institute, discusses an interim study analysis showing that ultrasound-guided core biopsies of the breast in patients with excellent response on MRI after neoadjuvant systemic therapy may not be accurate enough to safely select patients with pathologic complete response for omission of surgery (Abstract GS5-06).
