Kisqali (Ribociclib)

Kisqali acts on the cyclin‑dependent kinase pathway to control growth of certain breast cancers.

• Hormone receptor‑positive, HER2‑negative advanced breast cancer: improves progression‑free survival when combined with endocrine therapy.
• Hormone receptor‑positive, HER2‑negative metastatic breast cancer: delays disease progression in combination with letrozole.
• Post‑menopausal women with HR‑positive, HER2‑negative disease: used with fulvestrant to extend treatment benefit.

• Ribociclib selectively inhibits CDK4 and CDK6, key enzymes that drive cell‑cycle transition from G1 to S phase. By blocking these kinases, the drug induces G1‑phase arrest, reducing tumor cell proliferation and contributing to antitumor activity in hormone‑driven breast cancer.

Ribociclib may cause a range of adverse reactions.

Common Side Effects

• Neutropenia: reduced neutrophil count, increasing infection risk.
• Nausea: feeling of sickness, may be mild to moderate.
• Fatigue: persistent tiredness affecting daily activities.
• Diarrhoea: loose stools, can lead to dehydration.

Serious or Rare Side Effects

• QT interval prolongation: may cause cardiac arrhythmias.
• Severe liver injury: elevated transaminases or hepatitis.
• Interstitial lung disease: inflammation of lung tissue, potentially life‑threatening.

Before initiating therapy, clinicians should assess several safety parameters.

• Blood count monitoring: perform regular CBC to detect neutropenia.
• Liver function tests: evaluate ALT, AST, bilirubin before and during treatment.
• Cardiac assessment: obtain baseline ECG and monitor QT interval.
• Drug interaction review: avoid strong CYP3A4 inhibitors and QT‑prolonging agents.
• Contraception: advise women of child‑bearing potential to use effective contraception.
• Store at room temperature: keep in the original pack, protect from moisture.

Ribociclib can interact with several medicines, requiring careful management.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin): may increase ribociclib exposure.
• Potent QT‑prolonging drugs (e.g., sotalol, quinidine): raise risk of cardiac arrhythmia.
• CYP3A inducers (e.g., rifampin, carbamazepine): markedly reduce ribociclib levels.

Moderate Interactions (Monitor Closely)

• Moderate CYP3A4 inhibitors (e.g., fluconazole): may modestly raise ribociclib concentrations.
• Antacids containing aluminium or magnesium: can affect absorption, advise spacing of doses.