Atirmociclib

**Semantic type:** Pharmacologic Substance

**Definition:** An orally bioavailable inhibitor of cyclin-dependent kinase 4 (CDK4), with potential antineoplastic activity. Upon administration, atirmociclib selectively inhibits CDK4, which inhibits the phosphorylation of retinoblastoma protein (Rb) early in the G1 phase, prevents CDK-mediated G1-S-phase transition and leads to cell cycle arrest. This suppresses DNA replication and inhibits tumor cell proliferation. CDK4, a serine/threonine kinase, is upregulated in many tumor cell types and plays a key role in the regulation of both cell cycle progression from the G1-phase into the S-phase and tumor cell proliferation.

**Synonyms:** - ATIRMOCICLIB - CDK4 Inhibitor PF-07220060 - PF 07220060 - PF-07220060 - PF07220060