ESMO 2021: Long-Term Overall Survival With Letrozole Plus Ribociclib in Advanced Breast Cancer
Posted: Friday, September 24, 2021
Gabriel N. Hortobagyi, MD, of The University of Texas MD Anderson Cancer Center, Houston, and colleagues presented their overall survival results with more than 6.5 years of follow-up from the MONALEESA-2 trial during the European Society for Medical Oncology (ESMO) Congress 2021 (Abstract LBA17_PR). Previous results from this phase III trial revealed significant progression-free survival improvement with ribociclib plus letrozole compared with letrozole plus placebo in hormone receptor–positive/HER2-negative advanced breast cancer.
“Given these results, the combination of a CDK4/6 inhibitor plus an aromatase inhibitor should be the standard first-line treatment for the majority of patients with advanced hormone receptor–positive breast cancer,” Dr. Hortobagyi stated in an MD Anderson press release. “These findings have the potential to impact most women diagnosed with metastatic breast cancer.”
The intention-to-treat population consisted of 668 patients with hormone receptor–positive, HER2-negative advanced breast cancer who were randomly assigned to receive endocrine therapy (letrozole) with (n = 334) or without (n = 334) ribociclib. The median follow-up was 79.7 months, and 47 patients remained on treatment at data cutoff.
After 400 deaths between both groups, the median overall survival of patients who received ribociclib plus letrozole was revealed to be significantly longer than the survival of those given the placebo plus letrozole (63.9 vs. 51.4 months; P = .004). Additionally, the estimated 6-year overall survival rate for individuals given ribociclib plus letrozole was 44.2%, compared with 32.0% for those given placebo plus letrozole.
Although the time to first chemotherapy was longer among participants who received ribociclib plus letrozole, the median chemotherapy-free survival of both groups was similar (39.9 vs. 30.1 months). Of note, 87.8% versus 90.2% of individuals treated with ribociclib plus letrozole versus placebo plus letrozole who discontinued therapy received subsequent antineoplastic therapy, and 21.7% versus 34.4% received a subsequent CDK4/6 inhibitor.
Disclosure: For full disclosures of the study authors, visit oncologypro.esmo.org.
