Dr. Han on the Differences Between CDK 4/6 Inhibitors in ER+ Breast Cancer

Heather S. Han, MD, research director, medical oncologist, Department of Breast Oncology, Moffitt Cancer Center, discusses the differences between CDK 4/6 inhibitors and their efficacy as both single- and combination agents.

The efficacy of CDK 4/6 inhibitors are fairly similar. All 3 inhibitors improve progression-free survival in the first- and second-line settings in hormone receptor-positive metastatic breast cancer. The toxicity profiles, however, are slightly different. Abemaciclib (Verzenio) is commonly associated with diarrhea, gastrointestinal toxicity, and fatigue. Riboclicib (Kisqali) and palbociclib (Ibrance) are more similar in that they can lead to neutropenia.

Abemaciclib is the only therapy to be approved as a single-agent at a slightly higher continuous dosing schedule of 200 mg. Its approval was based on the data from the MONARCH 1 trial. Abemaciclib can be used continuously at either 150 mg or 200 mg twice a day, or in combination with endocrine therapy, she says.