Dr. Accordino on the Utility of CDK4/6 Inhibitors in HR+/HER2

Melissa K. Accordino, MD, MS, assistant professor of medicine, Division of Hematology/Oncology, Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, discusses the utility of CDK4/6 inhibitors in hormone receptor (HR)—positive, HER2-negative breast cancer.

Three CDK4/6 inhibitors, palbociclib (Ibrance), ribociclib (Kisqali), and abemaciclib (Verzenio) are approved for the frontline treatment of postmenopausal women with HR-positive, HER2-negative advanced or metastatic breast cancer. In July 2018, ribociclib was granted an expanded indication to include pre/perimenopausal women.

As such, CDK4/6 inhibitors have been widely adopted in the first-line setting as well as in the second-line setting for those who received alternative therapy in the first-line setting, explains Accordino.

Regarding efficacy, the trends for hazard ratio for progression-free survival are comparable across the phase III PALOMA-2, MONALEESA-7 and MONARCH 3 studies, says Accordino. The different toxicity profiles between palbociclib, ribociclib, and abemaciclib can help guide treatment selection.

Additionally, data suggest that abemaciclib has central nervous system activity. As such, patients with brain metastases may derive greater benefit with the agent compared with palbociclib or ribociclib, says Accordino.

Finally, abemaciclib can be given as a single agent as opposed to palbociclib and ribociclib, which are given with endocrine therapy, concludes Accordino.