CDK4/6 inhibitor + aromatase inhibitor
Checked 2026-09-09
HR-positive, HER2-negative advanced breast cancer, first line (and adjuvant abemaciclib or ribociclib for high-risk early disease)
One cycle
every 28 daysComponents
| Drug | Dose | Route | Days | Note |
|---|---|---|---|---|
Palbociclib 125 mg or ribociclib 400-600 mg once daily Small-molecule CDK4/6 inhibitor | days 1-21 of 28 | Oral | D1-21 | |
Abemaciclib (alternative) Small-molecule CDK4/6 inhibitor | 150 mg twice daily continuously | Oral | D1-28 | |
Letrozole Small-molecule aromatase inhibitor | 2.5 mg once daily | Oral | D1-28 |
Cycles
until progression (adjuvant: 2 years abemaciclib, 3 years ribociclib)
28-day cycle
Emetogenicity
Minimal (<10%)
G-CSF
Not routine
Notes
- Ribociclib: ECG for QTc at baseline, day 14 and cycle 2; avoid QT-prolonging drugs.
- Abemaciclib: diarrhoea in most patients, start loperamide at first loose stool.
Used in
Source
MONALEESA-2, NEJM 2016; NCCN Breast Cancer
Reference doses for a typical adult from the cited protocol or label. Doses are adjusted for renal and hepatic function, age, performance status and prior toxicity, and institutional protocols vary. Verify against the current label and your local protocol before treating. Not medical advice.
Other regimens for these cancers
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every 21 days
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every 21 days × 6-8
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every 21 days