Randomized phase 2 trial of ribociclib plus endocrine therapy vs combination chemotherapy for premenopausal aggressive HR+/HER- aBC

A multinational randomized phase 2 trial compared first-line ribocicib plus endocrine therapy (ET) versus combination chemotherapy (CT) of investigator’s choice for clinically aggressive HR-positive/HER2-negative advanced breast cancer (HR+HER2- aBC) in premenopausal women. Median duration of follow-up was 37.0 months. The mediane progression-free survival was 21.8 months in the ribociclib-ET group versus 12.8 months in the combination CT group (HR 0.61; p=0.003).The overall response rates were 66.1% in the ribociclib-ET group versus 61.8% in the combination CT group, and the median time to response was 4.9 months versus 3.2 months, respectively. Lower rates of symptomatic adverse events were observed in the ribociclib-ER group. The authors conclude that first-line ribociclib plus ET showed a significant PFS benefit, similar response rates, and better tolerability over combination CT in clinically aggressive HR+HER2- aBC in premenopausal patients.