SOLAR-1 study demonstrated a significant prolongation of progression-free survival (PFS) and 7.9-month improvement in median overall survival (OS) when alpelisib, an orally bioavailable, α-selective PI3K inhibitor and degrader, was added to fulvestrant treatment of patients with PIK3CA-mutated, hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced BC (Andre et al., 2019[2], 2021[3]). This evidence concerns the gene ERBB2 and breast cancer.