Alpelisib: A Novel Therapy for Patients With Mutated Metastatic Breast Cancer.

In the United States, 1 in 8 women will be diagnosed with invasive breast cancer in her lifetime. Breast cancer death rates are higher for women in the United States than any other cancer, followed by lung cancer (National Cancer Institute, 2019). More than 70% of breast cancers are hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative, and of those patients, 40% have driver mutations in the gene phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha () resulting in damaged phosphatidylinositol 3-kinase (PI3K) and uncontrolled cell growth (Mollon et al.