ribociclib succinate

The succinate salt form of ribociclib, 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.