Kisqali (Ribociclib)

• Kisqali is a targeted therapy used in the hormone receptor‑positive, HER2‑negative breast cancer pathway.
• Hormone receptor‑positive, HER2‑negative advanced breast cancer: delays disease progression and extends progression‑free survival.
• Hormone receptor‑positive, HER2‑negative metastatic breast cancer: improves progression‑free survival when combined with endocrine therapy.
• HR‑positive, HER2‑negative breast cancer in combination with endocrine agents: enhances overall treatment efficacy.

• Ribociclib selectively inhibits cyclin‑dependent kinases 4 and 6 (CDK4/6), preventing phosphorylation of the retinoblastoma protein. This blocks cell‑cycle transition from G1 to S phase, leading to cell‑cycle arrest and reduced proliferation of tumor cells that depend on CDK4/6 signaling.

Common Side Effects

• Neutropenia: reduced white blood cell count.
• Nausea and vomiting.
• Fatigue and asthenia.
• Diarrhea.
• Alopecia: hair thinning or loss.
• Elevated liver enzymes.

Serious or Rare Side Effects

• Severe neutropenia or febrile neutropenia.
• QT interval prolongation on ECG.
• Hepatotoxicity: significant liver injury.
• Interstitial lung disease or pneumonitis.
• Thrombocytopenia: low platelet count.
• Severe infections requiring hospitalization.

• Patients should be monitored closely for hematologic and cardiac effects.
• Dose adjustment: modify dose in patients with hepatic impairment.
• Monitor blood counts: perform regular CBC to detect neutropenia.
• Assess cardiac function: obtain baseline ECG and monitor QT interval.
• Avoid strong CYP3A4 inhibitors: concomitant use may increase ribociclib exposure.
• Pregnancy: not recommended; discuss risks with a healthcare professional.
• Store at below 25°C: keep in the original packaging, protect from moisture and light.

Ribociclib may interact with several medications affecting its metabolism and cardiac safety.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole): may markedly increase ribociclib levels.
• Strong CYP3A4 inducers (e.g., rifampin, carbamazepine): may reduce efficacy.
• QT‑prolonging drugs (e.g., certain antiarrhythmics, haloperidol): increase risk of cardiac arrhythmias.

Moderate Interactions (Monitor Closely)

• Moderate CYP3A4 inhibitors (e.g., erythromycin, clarithromycin): may modestly raise exposure.
• Other QT‑prolonging agents (e.g., fluoroquinolones, certain antihistamines): require ECG monitoring.
• Drugs affecting hepatic function (e.g., valproic acid): may alter metabolism.
• Concomitant endocrine therapies: monitor for additive toxicities.