CDK4 and breast carcinoma: In another phase II study, alpelisib plus fulvestrant proved their antitumor activity and manageable toxicity in patients with PI3KCA‐mutated, HR‐positive, HER2‐negative advanced breast cancer after progression on a CDK4/6 inhibitor plus an aromatase inhibitor, which offered a choice for these kinds of patients (NCT03056755).334