Mechanism of Action

Palbociclib is a reversible small molecule cyclin-dependent kinase (CDK) inhibitor which is selective for CDK 4 and 6. CDKs have a role in regulating progression through the cell cycle at the G1/S phase by blocking retinoblastoma (Rb) hyperphosphorylation (Finn 2015). Palbociclib reduces proliferation of breast cancer cell lines by preventing progression from the G1 to the S cell cycle phase.