Dr. Hurvitz on the Clinical Implications of the SUMMIT Trial in HER2-Mutated 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 the clinical implications of the ongoing phase 2 SUMMIT trial (NCT01953926) in HER2-mutated breast cancer.

Updated results from the SUMMIT trial, which were presented during the 2021 San Antonio Breast Cancer Symposium, demonstrated that the combination of neratinib (Nerlynx), fulvestrant (Faslodex), and trastuzumab (Herceptin) elicited encouraging clinical activity in patients with heavily pretreated hormone receptor (HR)–positive, HER2-mutated metastatic breast cancer who received prior CDK4/6 inhibitors. The overall objective response rate (ORR) was 42.4% and the median progression-free survival (PFS) was 7 months. Additionally, the combination demonstrated promising clinical activity in patients with HER2-mutated triple-negative breast cancer (TNBC). Here, the ORR was 33.3% and the median PFS was 6.2 months.

Additional research with a larger study is needed to further evaluate the utility of neratinib in patients with HER2-mutated breast cancer. Many patients have HER2 mutations in the absence of HER2 amplification, so this regimen provides another therapeutic option for patients with HR-positive breast cancer or TNBC that harbor HER2 mutations, Hurvitz concludes.