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Atirmociclib

Small molecule · Inhibitor of CDK4 · developed by Pfizer

Phase 1/2 Most advanced trial

3 Registered trials

What is Atirmociclib?

Atirmociclib is an orally bioavailable CDK4 inhibitor that selectively inhibits cyclin-dependent kinase 4, preventing retinoblastoma protein phosphorylation and blocking G1-S phase transition to arrest cell cycle progression. It is studied in breast cancer.

Summary written with AI from the sources listed at the end of this page.

At a glance

Also known as: PF-07220060
Drug type: Small molecule
Targets: CDK4
Mechanism: Inhibitor of CDK4
Pathways: G1/S cell cycle transition, Rb phosphorylation
Therapy area: Oncology
Developer: Pfizer
In trials of: ARVN, AZN, GILD
FDA status: Investigational, not approved in the US. Most advanced trial: Phase 1/2
UNII: S743GOJ5LJ

🧪 Clinical trials

Trial	Phase	Condition	Status	Sponsor
NCT07427394	Phase 2	Advanced Breast Cancer	Recruiting	AZN
NCT06206837	Phase 1/2	Breast Cancer	Active not recruiting	ARVN
NCT03424005	Phase 1/2	Metastatic Breast Cancer	Recruiting	GILD

Trials of the companies BioRadar tracks, from ClinicalTrials.gov, most advanced phase first.

Conditions studied

Advanced Breast CancerBreast CancerMetastatic Breast Cancer

Other drugs acting on CDK4

Abemaciclib FDA approved Inixaciclib Phase 1/2 Milciclib Phase 2

Sources

Updated Oct 3, 2026.

Data: FDA (Drugs@FDA, Purple Book, DailyMed), NIH (NCI Thesaurus, GSRS, RxNorm), ClinicalTrials.gov • Informational purposes only, not medical or investment advice. • All drugs A–Z