Dr. Williams on the Role of PI3K Inhibitors in HR+/HER2- Breast Cancer

Nicole O. Williams, MD, assistant professor-clinical, director, BreastCARE Program, Cancer and Aging Resiliency Clinic, Division of Medical Oncology, The Ohio State University Comprehensive Cancer Center–James, discusses the role of PI3K inhibitors in hormone receptor (HR)–positive, HER2-negative breast cancer.

Currently, PI3K inhibitors are used for the treatment of patients with HR-positive, HER2-negative breast cancer who progress on CDK4/6 inhibitors, says Williams. The PI3K inhibitor alpelisib (Piqray) was FDA-approved in May 2019 based on findings from the phase 3 SOLAR-1 trial (NCT02437318). The results demonstrated improved progression-free survival with alpelisib plus fulvestrant vs fulvestrant alone.

Genomic testing with next-generation sequencing can be used to identify PIK3CA mutations in patients with metastatic HR-positive, HER2-negative breast cancer, says Williams. In this patient population, approximately 40% of patients harbor these mutations, Williams adds. As such, tumor- or blood-based genomic testing can inform whether a PI3K inhibitor would be an optimal second-line treatment for a patient, concludes Williams.