Adding Ribociclib to Letrozole Prolongs Survival in Advanced Breast Cancer

THURSDAY, March 10, 2022 (HealthDay News) -- For postmenopausal patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer, the addition of ribociclib to letrozole as first-line therapy prolongs overall survival, according to a study published in the March 10 issue of the New England Journal of Medicine.

Gabriel N. Hortobagyi, M.D., from the University of Texas M.D. Anderson Cancer Center in Houston, and colleagues reported the results of the protocol-specified final analysis of overall survival in a phase 3 trial in which postmenopausal patients with HR-positive, HER2-negative advanced breast cancer were randomly assigned to receive either ribociclib or placebo in combination with letrozole.

The researchers found that 181 deaths among 334 patients and 219 deaths among 334 patients occurred in the ribociclib group and placebo group, respectively (54.2 versus 65.6 percent) after a median follow-up of 6.6 years. Significant overall survival benefit was seen for ribociclib plus letrozole versus placebo plus letrozole. The median overall survival was 63.9 versus 51.4 months with ribociclib plus letrozole versus placebo plus letrozole (hazard ratio for death, 0.76). There were no new safety signals.

"In our trial, the addition of ribociclib significantly prolonged overall survival as compared with letrozole alone when given to postmenopausal patients with HR-positive, HER2-negative advanced breast cancer exclusively as first-line therapy, with a risk of death that was 24 percent lower than that with placebo," the authors write.

The study was funded by Novartis; ribociclib was discovered by Novartis Institutes for BioMedical Research in collaboration with Astex Pharmaceuticals.

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