Hope S. Rugo, MD, FASCO, gave an overview of ribociclib plus aromatase inhibitor use vs abemaciclib plus aromatase inhibitors for patients with hormone receptor-positive, HER2-negative advanced breast cancer.
Hope S. Rugo, MD, director of Breast Oncology and Clinical Trials Education and professor of medicine in the Division of Hematology and Oncology at the University of California San Francisco (UCSF) Helen Diller Family Comprehensive Cancer Center, spoke with CancerNetwork® at the 2022 American Society of Clinical Oncology (ASCO) Annual Meeting about a matched-adjusted indirect comparison study which analyzed aromatase inhibitors (AIs) plus ribociclib (Kisqali) or abemaciclib (Verzenio) for patients with hormone receptor–positive, HER2-negative advanced breast cancer.1 Results from the study showed that ribociclib plus AI in the first-line setting produced better quality of life outcomes. She also spoke about past findings with ribociclib from several MONALEESA trials.
There are many clinical findings with ribociclib and endocrine therapy, and a number of different trials in pre-and peri-menopausal women, like MONALEESA-7 [NCT02278120], MONALEESA-2 [NCT01958021], and MONALEESA-3 [NCT02422615]. In MONALEESA-2, [treatment was used] in the first-line population with an aromatase inhibitor. In MONALEESA-3, [treatment was ribociclib plus] fulvestrant was in 2 different groups of patients. In the first-line, [patients were treated if they did] not progress on a prior aromatase inhibitor or endocrine therapy within a year; the second-line patients [were included who] already progressed on an AI and had progression of disease. In all of these trials, ribociclib demonstrated improved progression-free survival and overall survival.
Interestingly, the first trial to present an overall survival benefit was MONALEESA-7 in the pre-and peri-menopausal women. Then we saw overall survival data in the MONALEESA-3 populations. These were patients who were being treated with fulvestrant, but the trial combined the first- and second-line patients and then was able to gradually separate them out as they had enough events. It most recently showed in the first-line population an improvement in survival at [the 2022 European Society of Clinical Oncology Breast Symposium].2 The first-line study with aromatase inhibitors also showed an improvement in overall survival. It’s the only first-line study with an aromatase inhibitor to have presented survival data. There’s also the first-line combination with fulvestrant that showed survival data as a subset of the larger trial.
There had been a lot of concerns about QT prolongation and other issues. There’s been no fatal or even life-threatening arrhythmia events in patients taking ribociclib. We do the EKGs, but we don’t use the data. The most important thing for patients taking ribociclib is to make sure that they’re not taking drugs that prolong the QT interval. Other than that, it’s really a question of what the right dose is for individual patients. [A dose of] 600 mg causes a lot of neutropenia, so most patients reduce the dose to 400 mg.