Ribociclib: CDK4/6 Inhibitor for HR+/HER2- Breast Cancer
Ribociclib is an innovative, orally active targeted therapy classified as a CDK4/6 (cyclin-dependent kinase 4 and 6) inhibitor. It is a cornerstone treatment for advanced hormone-driven breast cancer.
By specifically inhibiting the CDK4/6 enzymes, Ribociclib blocks the progression of cancer cells from the G1 into the S phase of the cell cycle. This effectively hits the "pause button" on tumor growth and cellular division.
It is prescribed exclusively in combination with endocrine therapy (such as an aromatase inhibitor or fulvestrant) because the synergistic effect significantly delays disease progression and extends overall survival compared to hormone therapy alone.
Indications
- Advanced Breast Cancer: Indicated for the treatment of pre/perimenopausal or postmenopausal women, and men, with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic breast cancer.
- Used in combination with an aromatase inhibitor as initial endocrine-based therapy, or with fulvestrant as initial therapy or following disease progression on endocrine therapy.
Dosage and administration
Ribociclib is administered orally in a 28-day cycle.
- Recommended Dose: 600 mg (three 200 mg tablets) taken orally once daily for 21 consecutive days.
- Rest Period: Followed by 7 days off treatment. (The co-administered endocrine therapy is usually taken continuously for the entire 28-day cycle).
- Administration: Take at approximately the same time each day, with or without food. Swallow tablets whole; do not chew, crush, or split them prior to swallowing. Avoid grapefruit or grapefruit juice.
- Cardiac Issues: Patients with a baseline QTcF interval >450 ms, or those at significant risk for QT prolongation.
- Drug Interactions: Concurrent use of strong CYP3A4 inhibitors or inducers.
- Pregnancy and breastfeeding (embryo-fetal toxicity risk).
- Known hypersensitivity to Ribociclib or any of the excipients.
Frequent clinical and laboratory monitoring (CBC, liver function, ECG) is mandatory.
- Hematologic: Neutropenia (most common), leukopenia, anemia.
- Hepatic: Hepatotoxicity with elevated AST/ALT levels.
- Cardiac: Dose-dependent QT interval prolongation.
- Gastrointestinal & General: Nausea, fatigue, diarrhea, alopecia (hair thinning), vomiting.
