The combination of ribociclib and endocrine therapy improved PFS in the first-line setting for premenopausal patients with aggressive ER-positive, HER2-negative advanced breast cancer.

In the randomized phase II, RIGHT Choice trial, presented in SABCS-2022, 222 patients with visceral metastases, rapid disease progression, or symptomatic non-visceral disease with no prior systemic treatment for advanced breast cancer were randomized to receive ribociclib plus endocrine therapy or combination chemotherapy. The primary end point was PFS.

After a median follow-up of 24.1 months, the median PFS was 24 months with ribociclib versus 12.3 months with chemotherapy ( HR, 0.54, P = .0007). In addition the response rate was 65.5% with ribociclib and vs 60.0% with chemotherapy. As expected, adverse events were less frequent with endocrine therapy plus ribociclib compared to chemotherapy.