At the San Antonio Breast Cancer Symposium, an exploratory subgroup analysis of the MONALEESA-2 trial was presented, showing a consistent overall survival (OS) benefit for postmenopausal women who received ribociclib in addition to letrozole regardless of the site or number of metastases, and regardless of prior therapy.
In this exclusive 51˶ video, , of the Cleveland Clinic, discusses the data and clinical implications.
Following is a transcript of her remarks:
In a subgroup analysis of the MONALEESA-2 study, which was presented by Joyce O'Shaughnessy, MD [of Texas Oncology-Baylor Charles A. Sammons Cancer Center in Dallas], investigators looked at the overall survival impact of ribociclib added to letrozole by sites of metastatic disease.
In MONALEESA-2, postmenopausal women with previously untreated metastatic hormone receptor (HR)-positive/HER2-negative breast cancer were randomized to receive letrozole plus ribociclib or letrozole plus placebo.
The overall survival results in the study were previously presented, and demonstrated a significant survival benefit to the addition of ribociclib with a 63.9 month survival compared with a 51.4 month survival among those randomized to placebo.
In the exploratory subset analysis, which was presented at the recent San Antonio Breast Cancer Symposium, overall survival was assessed by whether participants had bone-only disease or not, whether they had liver involvement, liver or lung involvement, and also by whether or not there were three or more metastatic sites. The investigators found that the survival benefit to the addition of ribociclib to letrozole was similar across all subsets evaluated.
The implication of these findings is that currently based on site or extent of metastatic disease, we are not able to pick out a group of the first-line hormone receptor-positive/HER2-negative metastatic breast cancer patients that does not benefit from the addition of ribociclib to letrozole.