The PIKHER2 trial demonstrated a clinical benefit rate (CBR) of 29% when Buparlisib was combined with lapatinib in patients with advanced HER2+ BC who were resistant to trastuzumab and had PIK3CA mutations, with one patient (4%) achieving a complete response (CR), indicating the feasibility of this combination regimen [143]. The gene discussed is ERBB2; the disease is breast cancer.