Alpelisib Plus Fulvestrant in PIK3CA-Altered and PIK3CA-Wild-Type Estrogen Receptor–Positive Advanced Breast Cancer

Abstract

Breast cancer is the most frequently diagnosed cancer in women worldwide, with approximately 75% of metastatic breast cancers being estrogen receptor–positive (ER+).^1,2 The recommended treatment for patients with ER+ advanced breast cancer (ABC) is endocrine therapy, alone or with mammalian target of rapamycin (mTOR) or cyclin-dependent kinase 4/6 inhibitors.^3-5 However, resistance and disease progression eventually occur.⁶