Expert: Selective inhibitor of cyclin-dependent kinases 4 and 6, inducing G1 cell cycle arrest in Rb-positive tumor cells. Continuous dosing maintains sustained target inhibition.

Everyday: Blocks proteins that help cancer cells divide, slowing tumor growth in hormone-receptor positive breast cancer.

Targets: ["CDK4/6"]

Abemaciclib, a CDK4/6 inhibitor for HR+/HER2- breast cancer. Most potent and selective CDK4 inhibitor in class; only CDK4/6 inhibitor with continuous daily dosing and single-agent activity in breast cancer.