Ribociclib Plus Fulvestrant for Advanced Breast Cancer: Update From MONALEESA-3
Posted: Monday, February 3, 2020
The combination of the CDK4/6 inhibitor ribociclib and the hormone therapy fulvestrant improved overall survival in postmenopausal patients with hormone receptor–positive, HER2-negative advanced breast cancer, based on the protocol-specified second interim analysis of overall survival from the MONALEESA-3 trial. According to Dennis J. Slamon, MD, PhD, of the Ronald Reagan UCLA Medical Center, Santa Monica, and colleagues, the benefit was found to be consistent across most subgroups. Their data were published in The New England Journal of Medicine.
“The addition of ribociclib to fulvestrant was associated with a significant benefit with respect to overall survival, with a 28% relative difference in the risk of death as compared with placebo,” concluded the study authors. “These data support the further study of ribociclib, including in the treatment of early breast cancer.”
From June 2015 to June 2016, 726 patients were randomly assigned in a 2:1 ratio to receive either ribociclib (484 patients) or placebo (242 patients) in addition to fulvestrant as first-line or second-line treatment. Initial analysis yielded significantly longer progression-free survival with ribociclib and fulvestrant than with placebo and fulvestrant (20.5 vs. 12.8 months).
This subsequent study reviewed mortality data, following patients until June 2019. Among the 275 total deaths, overall survival at 42 months was 57.8% in the ribociclib group and 45.9% in the placebo group. The median progression-free survival among patients receiving first-line therapy was 33.6 months with ribociclib, exceeding the previously established 28 months of first-line treatment with CDK4/6 inhibitors plus endocrine therapy in postmenopausal patients. The exception to ribociclib-attributed survival benefits was a small subgroup of Asian patients.
Adverse events were consistent with the first report. This subsequent analysis did not reveal any new safety signals.
Disclosure: For full disclosures of the study authors, visit nejm.org.