Dr. O'Regan on the RIGHT Choice Trial in HR+/HER2- Breast Cancer

Ruth M. O’Regan, MD, professor, chair, Charles Ayrault Dewey Professorship of Medicine, Department of Medicine, the University of Rochester, physician-in-chief, Strong Memorial Hospital, associate director, Education and Mentoring, the Wilmot Cancer Institute at University of Rochester, discusses how results from the phase 2 RIGHT Choice trial (NCT03839823) could influence the treatment paradigm in hormone receptor (HR)–positive, HER2-negative breast cancer.

The randomized, open-label, multi-center study was designed to compare ribociclib (Kisqali) plus endocrine therapy vs combination chemotherapy in premenopausal or perimenopausal patients with locally advanced or metastatic HR-positive, HER2-negative breast cancer, O’Regan begins. To be eligible for enrollment, patients had to display high-volume disease and either visceral metastases or impending visceral crisis, she states. A total of 223 patients entered the study. Patients were randomized to ribociclib plus goserelin acetate and either letrazole (Femara) or anastrozole (Arimidex) vs the physician’s choice of a chemotherapy doublet, O’Regan details.

Patients treated with the ribociclib combination had a superior progression-free survival compared with those who received the chemotherapy regimen, O’Regan states. However, both response rates and time to response were similar between both treatment arms, she adds. Notably, the experimental regimen was also associated with a lower incidence of serious drug-related adverse effects and treatment discontinuation rate.

This indicates that the regimen may produce quick and durable responses and antitumor activity that is comparable with standard-of-care chemotherapy, O’Regan says. This could alleviate concerns that a patient’s disease will worsen before the agent begins to work, she explains.

Accordingly, results from this study confirm the benefit of CDK4/6 inhibitors in patients with aggressive breast cancer and may lead to decreased use of chemotherapy approaches in the first-line setting, O’Regan concludes.

Editor's note: Dr. O’Regan reports relationships with Biotheranostics, Novartis, AstraZeneca, and Pfizer.