ribociclib
Kisqali (ribociclib) is an oral CDK4/6 inhibitor from Novartis for hormone receptor-positive, HER2-negative breast cancer. With endocrine therapy it is used for high-risk early breast cancer after surgery and for advanced or metastatic disease, blocking the cell-cycle machinery cancer cells use to multiply.
This page is based on FDA prescribing information and the EMA medicine record for ribociclib, cross-checked with DailyMed, MedlinePlus, and the National Cancer Institute dictionary; the mechanism is explained in plain language, and analogies are used only where they stay accurate.
How it works
Explains what the medicine does in the body, not dosing, side effects, or safety.
An analogy
A hormone-driven breast cancer is a factory with the divide button pressed down, and CDK4/6 are the two switches that keep it running. Ribociclib flips both switches off. The factory freezes at the checkpoint before copying its DNA, so no new cancer cells come off the line, and endocrine therapy meanwhile cuts the hormone supply the factory runs on.
In simple terms
Certain breast cancers depend on hormones and on the enzymes CDK4 and CDK6 to keep their division cycle turning. Ribociclib, taken by mouth, specifically binds and inhibits CDK4 and CDK6, which prevents phosphorylation of the retinoblastoma protein and arrests the cell cycle in the G1 phase. DNA synthesis is suppressed and cancer cell growth slows. Combined with endocrine therapy such as an aromatase inhibitor or fulvestrant, it helps control hormone receptor-positive, HER2-negative breast cancer in both early and advanced settings.
In depth
Ribociclib succinate is an orally available inhibitor of the cyclin-dependent kinases CDK4 and CDK6. Upon oral administration it specifically targets, binds to, and inhibits CDK4 and CDK6, blocking the cyclin D1/CDK4 and cyclin D3/CDK6 cell cycle pathways and inhibiting phosphorylation of the retinoblastoma (Rb) protein. Inhibition of Rb phosphorylation prevents CDK-mediated G1-S phase transition, arresting the cell cycle in G1, suppressing DNA synthesis, and inhibiting cancer cell growth. Overexpression of CDK4/6, as seen in certain types of cancer, causes cell cycle dysregulation that this inhibition corrects.
See it in motion
A schematic animation of the mechanism — simplified for clarity, not drawn to scale.
How ribociclib blocks the cyclin D1/CDK4 and cyclin D3/CDK6 pathways
- Ribociclib succinate is an orally available inhibitor of the cyclin-dependent kinases CDK4 and CDK6.
- Upon oral administration it specifically targets, binds to, and inhibits CDK4 and CDK6, blocking the cyclin D1/CDK4 and cyclin D3/CDK6 cell cycle pathways and inhibiting phosphorylation of the retinoblastoma (Rb) protein.
- Inhibition of Rb phosphorylation prevents CDK-mediated G1-S phase transition, arresting the cell cycle in G1, suppressing DNA synthesis, and inhibiting cancer cell growth.
- Overexpression of CDK4/6, as seen in certain types of cancer, causes cell cycle dysregulation that this inhibition corrects.
Target: Cyclin-dependent kinases 4 and 6 (CDK4, CDK6)
Kinases that drive cells past the early checkpoint of the division cycle via the cyclin D1/CDK4 and cyclin D3/CDK6 pathways; overexpression in certain cancers causes cell cycle dysregulation, so blocking them stalls division.
Approved uses
Approved uses differ by country and change over time. Always follow your local prescribing information.
Approved uses in United States
FDA- In combination with an aromatase inhibitor, for the adjuvant treatment of adults with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative stage II and III early breast cancer at high risk of recurrence
- In combination with an aromatase inhibitor as initial endocrine-based therapy, or with fulvestrant as initial endocrine-based therapy or following disease progression on endocrine therapy, for the treatment of adults with HR-positive, HER2-negative advanced or metastatic breast cancer
Approved uses in European Union
EMA- In combination with an aromatase inhibitor, for the adjuvant treatment of patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative early breast cancer at high risk of recurrence, with the aromatase inhibitor combined with a luteinising hormone-releasing hormone (LHRH) agonist in pre- or perimenopausal women or in men
- In combination with an aromatase inhibitor or fulvestrant as initial endocrine-based therapy, or in women who have received prior endocrine therapy, for the treatment of women with HR-positive, HER2-negative locally advanced or metastatic breast cancer, with endocrine therapy combined with an LHRH agonist in pre- or perimenopausal women
Official sources
The statements on this page trace back to these records.
- Kisqali (ribociclib) — Summary of product characteristics and package leaflet, English version
European Medicines Agency
- DailyMed: KISQALI (ribociclib) official US label
U.S. National Library of Medicine, DailyMed
- U.S. Food and Drug Administration: ribociclib prescribing information
U.S. Food and Drug Administration
- MedlinePlus: ribociclib
MedlinePlus, U.S. National Library of Medicine
- National Cancer Institute: ribociclib succinate
National Cancer Institute
This page explains how the medicine works — it isn’t the patient leaflet. For anything that applies to you, read the leaflet that came with your medicine or ask your pharmacist.
MedUnfold provides educational content and is not medical advice. Always follow your local prescribing information and healthcare professional.