A recent study published in The New England Journal of Medicine found that combination ribociclib/fulvestrant improved overall survival in hormone-receptor–positive, HER2-negative advanced breast cancer compared with fulvestrant plus placebo. 

Dennis J. Slamon, MD, PhD, of the David Geffen School of Medicine at UCLA, and colleagues conducted a second interim analysis of previous clinical trial results, focusing on overall survival benefit. 

Breast cancer cells. Source: Getty

“In an earlier analysis of this phase 3 trial, ribociclib plus fulvestrant showed a greater benefit with regard to progression-free survival than fulvestrant alone in postmenopausal patients with hormone-receptor–positive, human epidermal growth factor receptor 2 (HER2)–negative advanced breast cancer,” Slamon and colleagues wrote.

In the clinical trial, researchers randomized patients 2:1, with 484 patients receiving ribociclib with fulvestrant and 242 patients receiving placebo with fulvestrant. Treatments were administered as either first-line or second-line therapy. Statistical analysis was used to determine the comparative overall survival benefit.

Among the 275 patient deaths recorded during the clinical trial, 167 occurred in the combo therapy group and 108 occurred in the placebo group. 

The overall survival benefit was greater in the combo therapy group, with a 57% OS at 42 months compared to 45.9% in the placebo group (P = .00455). The difference in relative risk of death was 28% between the two study groups.

Additionally, the researchers observed no new adverse event signals. 

“Ribociclib plus fulvestrant showed a significant overall survival benefit over placebo plus fulvestrant in patients with hormone-receptor–positive, HER2-negative advanced breast cancer,” Slamon and colleagues concluded.

Disclosure: This study was supported by Novartis. The research team reported numerous industry disclosures. Please see the study for a full list of disclosures.