In a phase I study in patients with advanced solid tumors, pictilisib demonstrated antitumor activity, particularly in breast cancer models with phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit α (PIK3CA) mutations, and/or human epidermal growth factor receptor 2 (HER2) amplification [36]. This evidence concerns the gene PIK3CA and breast carcinoma.