What type of drug is Verzenio?
Verzenio (abemaciclib) is a small molecule drug and kinase inhibitor used in the treatment of both early breast cancer, and advanced or metastatic (cancer that has spread) breast cancer. Verzenio is used to treat both men and women. It works as an ATP-competitive inhibitor of cyclin-dependent kinases 4 and 6 (CDK4 and CDK6), which play a key role in cancer cell growth.
Is Verzenio Chemotherapy or Targeted Therapy?
Verzenio is not classified as chemotherapy; instead, it belongs to a newer group of cancer drugs called targeted therapies known as CDK4/6 inhibitors. Chemotherapy works by broadly killing fast-growing cells, which explains its potential for wide-ranging side effects. By contrast, Verzenio targets specific proteins involved in cell division, aiming to block cancer growth without the widespread cell death seen in chemotherapy.
FDA-Approved Uses of Verzenio
Verzenio is approved for the treatment of:
1. Early breast cancer:
- For patients at high risk of it coming back who have hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative, node-positive cancer.
- Used in combination with endocrine therapy (tamoxifen or an aromatase inhibitor).
2. Advanced or Metastatic Breast Cancer
- First-line therapy: In combination with an aromatase inhibitor for HR-positive, HER2-negative breast cancer that has worsened or spread.
- After endocrine therapy failure: In combination with fulvestrant (Faslodex) for HR-positive, HER2-negative breast cancer that has progressed.
- Monotherapy: For HR-positive, HER2-negative breast cancer that has progressed after both endocrine therapy and prior chemotherapy.
Related questions
- How long do you take Verzenio for?
- Is Verzenio better than Ibrance?
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Administration
Verzenio comes as an oral tablet that is taken with or without food. It is usually taken by mouth twice a day, but dose interruptions or reductions may be required at times. This medication comes in the following doses:
- 50 mg
- 100 mg
- 150 mg
- 200 mg
The dose depends on your condition and how well you tolerate the medication.
Side Effects and Safety Considerations
Verzenio’s most frequent side effect is diarrhea, which is typically manageable but can be severe and should be treated quickly to prevent dehydration. Other common adverse reactions include nausea, neutropenia (low white blood cells), fatigue, and loss of appetite. Patients are advised to report serious side effects to their healthcare provider or the FDA’s MedWatch program.
Special precautions include avoiding grapefruit products, monitoring for drug interactions (e.g., St. John's Wort), and ensuring effective birth control during treatment due to the risk of harming a fetus.
Summary
Verzenio helps slow the progression of breast cancer by inhibiting key enzymes involved in tumor growth. Consult your healthcare provider for specific treatment recommendations.
References
- Food and Drug Administration (FDA). Verzenio. Available from: https://www.accessdata.fda.gov/drugsatfda_docs/label/2023/208716s010s011lbl.pdf [Accessed March 20, 2023].
- Gelbert LM, Cai S, Lin X, et al. Preclinical characterization of the CDK4/6 inhibitor LY2835219: in-vivo cell cycle-dependent/independent anti-tumor activities alone/in combination with gemcitabine. Invest New Drugs. 2014;32(5):825-837. doi:10.1007/s10637-014-0120-7.
- MedlinePlus. (n.d.). Abemaciclib: MedlinePlus Drug Information. MedlinePlus. Accessed on September 5, 2025, from https://medlineplus.gov/druginfo/meds/a617049.html
- National Cancer Institute (NCI). (2017, October 26). Abemaciclib Approved by FDA for Advanced or Metastatic Breast Cancer. National Cancer Institute. Accessed on September 5, 2025 at https://www.cancer.gov/news-events/cancer-currents-blog/2017/fda-abemaciclib-breast-cancer
Read next
How long does it take Verzenio to work?
Although Verzenio starts inhibiting CDK4/6 enzymes quickly, it may take up two to four months before any change in outcomes, such as progression-free survival, are noted. Side effects, such as diarrhea usually occur within the first week or month of treatment. Verzenio reaches consistent blood levels within five days of taking it twice a day.
Continue reading
Is Verzenio (abemaciclib) a chemo drug?
Verzenio is considered a targeted treatment, rather than being a chemo drug, but it may be used to treat certain types of breast cancer. Verzenio belongs to the class of medicines known as CDK 4/6 inhibitors which help to reduce the growth and spread of cancer cells in the body. Continue reading
How effective is Verzenio?
Trials have indicated that Verzenio plus endocrine therapy (ET) is more effective than ET alone at decreasing the risk of breast cancer recurrence and death by improving rates of invasive disease-free survival (IDFS). 4-year data from the monarchE trial showed 85.5% of patients remained recurrence-free after 4 years compared to 78.6% of those assigned ET alone (an absolute difference of 6.9%). Verzenio plus ET reduces the risk of recurrence by 35% compared to ET alone. Continue reading
See also:
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Drug information
- Verzenio Information for Consumers
- Verzenio prescribing info & package insert (for Health Professionals)
- Side Effects of Verzenio (detailed)
- Verzenio user reviews (37)
Related support groups
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