Multinational phase 2 trial of alpelisib plus fulvestrant in PIK3CA-mutated, HR-positive advanced breast cancer after a CDK4/6 inhibitor

Cohort A of the multinational phase 2 BYLieve trial evaluated the combination of alpelisib and fulvestrant for HR-positive, HER2-negative PIK3CA-mutated advanced breast cancer with progression on or after a CDK4/6 inhibitor plus an aromatase inhibitor as immediate previous treatment. The primary endpoint was the proportion of patients alive without disease progression at 6 months. Among 119 patients with centrally confirmed PIK3CA mutation, 64 (53.8%; 95% CI 44.4-63.0) were alive without disease progression at 6 months. The toxicity was manageable and there were no treatment-related deaths. The authors conclude that BYLieve found activity of alpelisib plus fulvestrant for PIK3CA-mutated, HR-positive, HER2-negative advanced breast cancer after progression on a CDK4/6 inhbitor plus an aromatase inhibitor.