Treatment With Ribociclib Dose Modifications Demonstrated Overall Benefit in HR+/HER2- Advanced Breast Cancer

In an exploratory analysis of data from the MONALEESA (ML)-2 trial, overall survival benefit was maintained in patients with HR+/HER2- advanced breast cancer who required modification from a recommended starting dose of ribociclib at 600 mg/d for 3 weeks followed by 1 week off of the treatment, according to a poster presented at the 2022 American Society of Clinical Oncology (ASCO) Annual Meeting.

In addition to the results of the ML-2 trial, the phase 3 ML-3 and ML-7 trials also established consistent and statistically significant overall survival benefit for patients treated with ribociclib at the starting dose of 600 mg/d for 3 weeks on and 1 week off versus patients with HR+/HER2- advanced breast cancer who were given placebo.

During the ML-2 trial, the research team enrolled postmenopausal patients randomized 1:1 to first-line ribociclib plus letrozole or placebo plus letrozole. Analyses of the overall survival (OS) data from the trial were performed to evaluate the association between dose reductions and OS. Additionally, the 2-time dependent variables, dose reduction, and relative dose intensity 2 (RDI2) were included in the respective model as covariates to explore the connection to OS.

At cutoff, 209 of 334 patients had a less than 1 ribociclib dose reduction, and 125 of 334 had no ribociclib dose reduction. In patients with low, medium, and high RDI2, median overall survival was 62.6 months, 63.9 months, and 65.3 months, respectively.

The researchers concluded that there was no relationship between overall survival and ribociclib dose reduction or RDI2, and overall benefit with ribociclib was observed in all groups.

REFERENCE

Impact of ribociclib (RIB) dose modifications (mod) on overall survival (OS) in patients (pts) with HR+/HER2- advanced breast cancer (ABC) in MONALEESA(ML)-2. 2022 ASCO Annual Meeting. Accessed June 7, 2022. 10.1200/JCO.2022.40.16_suppl.1017