Ribociclib

What it is and how it works

Mechanism of Action Ribociclib is an inhibitor of cyclin-dependent kinase (CDK) 4 and 6. These kinases are activated upon binding to D-cyclins and are downstream of signaling pathways which lead to cell cycle progression and cellular proliferation. The cyclin D-CDK4/6 complex regulates cell cycle progression through phosphorylation of the retinoblastoma protein (pRb). In vitro , ribociclib decreased pRb phosphorylation, resulting in arrest in the G1 phase of the cell cycle and reduced proliferation in breast cancer-derived models.

Indications

is a kinase inhibitor indicated: 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. for the treatment of adults with HR-positive, HER2-negative advanced or metastatic breast cancer in combination with: an aromatase inhibitor as initial endocrine-based therapy; or fulvestrant as initial endocrine-based therapy or following disease progression on endocrine therapy. Early Breast Cancer KISQALI is indicated 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. Advanced or Metastatic Breast Cancer KISQALI is indicated for the treatment of adults with HR-positive, HER2-negative advanced or metastatic breast cancer in combination with: an aromatase inhibitor as initial endocrine-based therapy.

Dosage and administration (summary)

tablets are taken orally with or without food in combination with an aromatase inhibitor or fulvestrant. Early Breast Cancer Recommended starting dose: 400 mg orally (two 200 mg tablets) taken once daily with or without food for 21 consecutive days followed by 7 days off treatment. Advanced or Metastatic Breast Cancer Recommended starting dose: 600 mg orally (three 200 mg tablets) taken once daily with or without food for 21 consecutive days followed by 7 days off treatment. Dose interruption, reduction, and/or discontinuation may be required based on individual safety and tolerability. Recommended Dosage Important Administration Instructions KISQALI can be taken with or without food .

Contraindications

None. None.

Warnings and precautions

Interstitial Lung Disease (ILD)/Pneumonitis: Severe, life threatening, or fatal ILD/pneumonitis can occur with KISQALI treatment. Monitor for pulmonary symptoms indicative of ILD/pneumonitis. Interrupt and evaluate patients with new or worsening respiratory symptoms suspected to be due to ILD/pneumonitis. Permanently discontinue KISQALI in patients with recurrent symptomatic or severe ILD/pneumonitis.

Pregnancy

Pregnancy Risk Summary Based on findings from animal studies and the mechanism of action, KISQALI can cause fetal harm when administered to a pregnant woman . There are no available human data informing the drug-associated risk.

Storage and supply

(ribociclib) Tablets Each film-coated tablet contains 200 mg of ribociclib free base. Light greyish violet, round, curved with beveled edge, debossed with “RIC” on one side and “NVR” on the other side.

Source: Ribociclib (Kisqali) — US FDA prescribing information, 2026-07-01, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.