Abemaciclib
VERZENIO
What it isCDK4/6 inhibitor; hormone receptor-positive HER2-negative breast cancer.
Why this oneIt is the only CDK4/6 inhibitor with a monotherapy indication and is given continuously rather than cyclically.
What limits itDiarrhea is its dose-limiting signature; treat at the first loose stool. Venous thromboembolism and CYP3A4 interactions also matter.
FDA-approved for
- HR-positive HER2-negative breast cancer (2017)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| HR+/HER2− breast cancer — with endocrine therapy (fulvestrant, tamoxifen, or an aromatase inhibitor) | adult | 150 mg BID | 150 mg BID | 150 mg BID |
| HR+/HER2− breast cancer — monotherapy | adult | 200 mg BID | 200 mg BID | 200 mg BID |
Renal No adjustment for mild–moderate impairment (CLcr ≥30 mL/min); severe/ESRD/dialysis not studied.
Hepatic No adjustment for mild–moderate (Child-Pugh A/B); severe (Child-Pugh C): reduce dosing frequency to once daily.
Instructions
- Take at about the same times every day, with or without food.
- Swallow tablets whole; do not chew, crush, or split; do not ingest broken or cracked tablets.
- If a dose is missed or vomited, take the next dose at its scheduled time.
- At the first sign of loose stools, start an antidiarrheal (e.g., loperamide) and increase oral fluids.
- Discontinue in patients unable to tolerate 50 mg BID.
Cautions
- Diarrhea (can be severe with dehydration and infection)
- Neutropenia (including febrile and fatal neutropenic sepsis)
- Interstitial lung disease/pneumonitis (severe, life-threatening, or fatal)
- Hepatotoxicity (transaminase elevations)
- Venous thromboembolism
- Embryo-fetal toxicity
Adverse reactions
- diarrhea, neutropenia, nausea, abdominal pain, infections, fatigue, anemia, leukopenia, decreased appetite, vomiting, headache, alopecia, thrombocytopenia
Pregnancy Can cause fetal harm (teratogenic in animals); advise effective contraception during treatment and for 3 weeks after the last dose.
Lactation Advise not to breastfeed during treatment and for 3 weeks after the last dose.
NO BOXED WARNINGS
Principal riskDiarrhea, near-universal and dose-limiting
Cost, est. cash$5,000–$30,000+/month or cycle
Generic entry2029 est.
Classes and tags
Clinical profile
Legacy pregnancy categoryNot assigned — PLLR-era drug
Defining liabilityMyelosuppression and agent-specific hepatic, cardiac, pulmonary, neurologic or reproductive toxicity require oncology monitoring.
Mechanism of action: Abemaciclib ballicule
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Memory aids: mascots and interaction avatars
