Ribociclib

**Semantic type:** Pharmacologic Substance

**Definition:** An orally available inhibitor of the cyclin-dependent kinases (CDKs) 4 and 6, with antineoplastic activity. Upon oral administration, ribociclib specifically targets, binds to and inhibits CDK4 and CDK6. This inhibits the cyclin D1/CDK4 and cyclin D3/CDK6 cell cycle pathway, which inhibits phosphorylation of the retinoblastoma (Rb) protein. Inhibition of Rb phosphorylation prevents CDK-mediated G1-S phase transition, thereby arresting the cell cycle in the G1 phase, suppressing DNA synthesis and inhibiting cancer cell growth. Overexpression of CDK4/6, as seen in certain types of cancer, causes cell cycle dysregulation.

**Synonyms:** - 7-Cyclopentyl-N,N-dimethyl-2-((5-(piperazin-1-yl)pyridin-2-yl)amino)-7H-pyrrolo[2,3-d]pyrimidine-6-carboxamide - LEE 011 - LEE-011 - LEE011 - RIBOCICLIB