USA: Recent data from MONALEESA-2 revealed that first-line therapy with a combination of ribociclib plus letrozole showed a significant overall survival benefit versus placebo plus letrozole in patients with HR-positive, HER2-negative advanced breast cancer, according to a recent study. With ribociclib, median overall survival was more than 12 months than with placebo. The study was published in the New England Journal of Medicine on March 10, 2022.

In a previous analysis of the phase 3 trial, first-line ribociclib plus letrozole was shown to be associated with longer progression-free survival than letrozole alone among postmenopausal patients with hormone receptor (HR)–positive, human epidermal growth factor receptor 2 (HER2)–negative advanced breast cancer. However, it was not known if overall survival would also be longer with ribociclib.
In the study, Gabriel N. Hortobagyi and the team report the results of the protocol-specified final analysis of overall survival, a key secondary endpoint. Patients were randomly assigned in a ratio of 1:1 to receive either ribociclib or placebo in combination with letrozole. The use of a stratified log-rank test was used to assess overall survival and summarized with the use of Kaplan–Meier methods after 400 deaths had occurred. For the analysis of progression-free survival and overall survival, a hierarchical testing strategy was used to ensure the validity of the findings.
The study revealed the following findings:
After a median follow-up of 6.6 years, 181 deaths had occurred among 334 patients (54.2%) in the ribociclib group and 219 among 334 (65.6%) in the placebo group.
Ribociclib plus letrozole showed a significant overall survival benefit as compared with placebo plus letrozole.
Median overall survival was 63.9 months with ribociclib plus letrozole and 51.4 months with placebo plus letrozole (hazard ratio for death, 0.76).
No new safety signals were observed.
The authors concluded, "In patients with HR-positive, HER2-negative advanced breast cancer, first-line therapy with ribociclib plus letrozole showed a significant overall survival benefit as compared with placebo plus letrozole."
Reference:
The study titled, "Overall Survival with Ribociclib plus Letrozole in Advanced Breast Cancer," was published in the New England Journal of Medicine.
DOI: 10.1056/NEJMoa2114663
KEYWORDS: NEJM, ribociclib, letrozole, breast cancer, cancer drugs, cancer treatment, cancer survival, overall survival, HR-positive, HER2-negative, advanced breast cancer, Gabriel N Hortobagyi, first line therapy