CDK4/6 inhibitor
- Prevents RB (retinoblastoma protein) phosphorylation
- Arrests the cell cycle at G1 → ↓ hormone-receptor-positive breast cancer growth
- Bone-marrow cell-cycle arrest → neutropenia, reversible by design
- Neutropenia is dose limiting
Drugs with this mechanism (3)
- Abemaciclib — CDK4/6 inhibitor dosed continuously; more diarrhea, less neutropenia than palbociclib.
- Palbociclib — CDK4/6 inhibitor for HR-positive breast cancer; dose-limiting neutropenia.
- Ribociclib — CDK4/6 inhibitor for hormone-receptor-positive breast cancer.
Self-check
- At which cell-cycle phase do CDK4/6 inhibitors arrest cells?
G1. - What adverse effect limits CDK4/6 inhibitor dosing?
Neutropenia.
All mechanisms · Open CDK4/6 inhibitor in the interactive console ↗