Verzenio: 7 things you should know - (2023)

Medically reviewed by Carmen Fookes, BPharm. Last updated on Dec 21, 2022.

1. How it works

  • Verzenio is a brand (trade) name for abemaciclib which may be used to treat certain types of breast cancer.
  • Verzenio (abemaciclib) works by inhibiting two particular enzymes, called CDK4 and CDK6. CDK stands for cyclin-dependent kinase, and it is an enzyme that is important for cell division. CDK4/6 inhibitors interrupt signals that stimulate the proliferation of malignant (cancerous) cells. Certain cancers, for example, hormone-receptor-positive breast cancer, are more likely to have disturbances in CDK4/6, and CDK 4/6 inhibitors can help to reduce the growth and spread of cancer cells in the body. Verzenio is usually given when cancer has progressed or spread to other parts of the body after treatments such as anti-estrogens or chemotherapy.
  • Verzenio belongs to the class of medicines known as CDK4/6 inhibitors.

2. Upsides

  • May be used to treat adults with HR+ HER2- early breast cancer at high risk of recurrence and a Ki 67 score of at least 20% (by FDA-approved test) in combination with endocrine treatment (tamoxifen or an aromatase inhibitor).
  • May be used with an aromatase inhibitor (such as Arimidex or Femara) as initial endocrine-based therapy for the treatment of postmenopausal women, or men, with hormone receptor-positive, human epidermal growth factor 2-negative (HR+ HER2-) advanced, or metastatic breast cancer.
  • Can be given in combination with fulvestrant (Faslodex) in women or men with HR+ HER2- advanced or metastatic breast cancer whose disease has progressed following endocrine therapy.
  • May be given as monotherapy in adult patients with HR+ HER2- advanced or metastatic breast cancer with disease progression following endocrine therapy and chemotherapy for metastatic disease.
  • Taken orally (by mouth) twice a day, every day.
  • Can be used as monotherapy or in combination with other treatments.
  • Research suggests CDK4/6 inhibitors may increase the time people have before cancer spreads. More evidence is needed to determine their impact on overall survival.
  • Considered a targeted treatment, rather than chemotherapy.
  • No dosage adjustment is needed in mild to moderate liver or kidney disease. Reduce dosage with severe hepatic impairment. The effects of Verzenio in severe kidney disease are unknown.
  • May be taken with or without food.

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

  • Common side effects include fatigue and gastrointestinal disturbances, such as nausea, severe diarrhea, and vomiting. Bone marrow suppression resulting in neutropenia and leukopenia may also occur, although anemia and thrombocytopenia are less common. In general, the side effects associated with CDK4/6 inhibitor therapy are less severe than those experienced with chemotherapy.
  • Gastrointestinal side effects, such as diarrhea, typically occur in the first month of treatment and can affect up to 81% of patients. The average time to onset of diarrhea was 6 to 8 days. Diarrhea can be severe and requires monitoring and proper management.
  • Infections, decreased appetite, headache, and hair thinning or hair loss (alopecia) have also been reported.Diarrhea
  • More likely than Ibrance to cause diarrhea; however, most patients can manage this side effect with the anti-diarrhea medication loperamide.
  • On average, 12% to 27% of patients who received Verzenio experienced hair thinning or loss. Patients taking Verzenio plus an aromatase inhibitor (such as letrozole or anastrozole) experienced the greatest risk of hair thinning or loss at 27% of patients.
  • May affect some laboratory test results such as alanine aminotransferase, aspartate aminotransferase, and creatinine.
  • Verzenio may cause fetal harm if administered during pregnancy and should not be given to pregnant women. Breastfeeding is also not recommended.
  • No generic is available.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

Verzenio (abemaciclib) is a targeted treatment that helps to reduce the growth and spread of cancer cells in the body. It may be used to treat early breast cancer at high risk of recurrence and a Ki 67 score of at least 20% (by FDA-approved test) in adults and also advanced HR+ HER2- metastatic breast cancer. Diarrhea commonly occurs in the first month of treatment and can affect up to 90% of patients, but can usually be treated with antidiarrheals.

5. Tips

  • Swallow the Verzenio tablet whole. Do not chew, crush, or split the tablets before swallowing them. Take each dose at about the same time every day. May be taken with or without food.
  • Do not stop taking Verzenio or change your dose unless your doctor tells you to. Verzenio is a treatment you will usually continue to take until your breast cancer progresses or side effects become intolerable. Do not stop this treatment unless your doctor tells you to. If you are having severe side effects, call your doctor immediately.
  • If you should vomit or miss a dose for any reason, do not take an additional dose of Verzenio. Take your next dose at the normal time.
  • Diarrhea is a common side effect occurring in 81% to 90% of patients and can sometimes be severe. In most cases, the median time until patients had the first symptoms of diarrhea was about seven to eight days. Moderate to more significant diarrhea lasted between roughly 5 to 11 days but was variable based on studies. However, diarrhea can lead to dehydration or infection. At the first sign of loose stools, tell your doctor. Diarrhea can be managed by your doctor with an anti-diarrhea medication such as loperamide (Imodium). Your doctor may also decide to reduce your dose. About 15% to 25% of patients may need a dose omission or dose lowering due to diarrhea, but this can vary between patients. Be sure you have an over-the-counter anti-diarrhea medicine, such as loperamide (Imodium) available at home before you start taking Verzenio. Work out an action plan with your doctor about how to address diarrhea if it occurs.
  • Tell your doctor if you experience any intolerable side effects, such as shortness of breath, cough, vomiting, abdominal pain, extreme tiredness, bleeding or bruising more easily than normal, pain or swelling in the arms or legs, or any type of infection. Your doctor may decide that a dose interruption or a dose reduction is needed based on how you are tolerating Verzenio treatment. For severe side effects, a dose reduction or interruption may be needed, and your doctor can advise you on the best course of treatment. Certain medications can be used temporarily that may help with some effects, too.
  • Studies have shown that Verzenio may prolong your overall survival or length of time before the disease worsens. Therefore, if you choose treatment, it is important you continue your medication exactly as your doctor has prescribed.
  • Avoid grapefruit products while taking Verzenio. Grapefruit may increase the amount of Verzenio in your blood due to a drug-food interaction.
  • Verzenio may harm a developing fetus and should not be given to pregnant women. Males and women of reproductive potential should use effective contraception during treatment with Verzenio and for at least 3 weeks after the last dose.

6. Response and effectiveness

  • Women taking Verzenio plus aromatase inhibitors experienced a longer progression-free survival than those taking a placebo (28.2 months compared to 14.8 months). 55% of women experienced a complete or partial response to Verzenio plus an aromatase inhibitor.
  • For women taking Verzenio as monotherapy, 19.7% saw their tumors shrink by 30% or more.
  • For women taking Verzenio in combination with fulvestrant fewer women experienced an “event” that impacted their progression-free survival: 49.8% of women taking Verzenio experienced an event compared to 70.4% of those taking the placebo combination
  • Verzenio plus fulvestrant helped women live significantly longer when compared to fulvestrant alone. In a clinical study, women taking Verzenio plus fulvestrant lived for a median of 46.7 months compared to 37.3 months on fulvestrant alone, regardless of menopausal status. In the same study, Verzenio plus fulvestrant delayed disease progression for a median of 16.4 months compared to 9.3 months in the group that received fulvestrant alone.
  • 48.1% of women responded to the Verzenio combination compared with 21% of women taking the placebo combination.
  • For women taking Verzenio as monotherapy, 19.7% of women saw their tumors shrink by 30% or more. The average duration of response was 8.6 months.
  • Verzenio is usually taken twice daily. When taken regularly, consistent blood levels are achieved within five days.
  • Although Verzenio starts inhibiting CDK4/6 enzymes quickly, it may take up to 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.
  • The median duration of response to treatment was 8.6 months (7.2 months by an independent review).
  • Research has shown breast cancer cells can acquire resistance to CDK 4/6 inhibitors by producing higher amounts of CDK6. Laboratory trials showed a “treatment holiday” of 28 days reversed this resistance. Because of this, there may be some benefit of either stopping Verzenio temporarily or switching from Verzenio to Ibrance after a treatment break. Comparative trials comparing Verzenio to Ibrance are currently underway with results expected in 2022.

7. Interactions

Medicines that interact with Verzenio may either decrease its effect, affect how long it works for, increase side effects, or have less of an effect when taken with Verzenio. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with Verzenio include:

  • anticonvulsants such as carbamazepine, phenytoin or phenobarbital
  • antipsychotics, such as clozapine
  • biologics, such as adalimumab or baricitinib
  • chloramphenicol
  • ciprofloxacin or gatifloxacin
  • echinacea
  • grapefruit or grapefruit juice
  • HIV medications, such as amprenavir, atazanavir, fosamprenavir, and ritonavir
  • live vaccines, such as the BCG vaccine, live influenza vaccine, or the measles vaccine
  • metformin
  • rifampin
  • St. John's Wort
  • strong and moderate CYP3A inducers (eg, phenytoin, rifampin, carbamazepine, enzalutamide, and St John's Wort). Avoid coadministration with Verzenio if possible
  • strong and moderate CYP3A inhibitors (eg, clarithromycin, indinavir, itraconazole, ketoconazole, lopinavir/ritonavir, nefazodone, nelfinavir, posaconazole, ritonavir, saquinavir, telaprevir, telithromycin, and voriconazole). Avoid ketoconazole because it can increase the AUC of Verzenio by up to 16-fold. For other CYP3A inhibitors consider a dosage reduction in Verzenio.

Note that this list is not all-inclusive and includes only common medications that may interact with Verzenio. You should refer to the prescribing information for Verzenio for a complete list of interactions.

More about Verzenio (abemaciclib)

  • Check interactions
  • Compare alternatives
  • Reviews (7)
  • Drug images
  • Latest FDA alerts (1)
  • Side effects
  • Dosage information
  • During pregnancy
  • FDA approval history
  • Drug class: CDK 4/6 inhibitors
  • Breastfeeding
  • En español

Patient resources

  • Drug Information

Professional resources

  • Prescribing Information

Related treatment guides

  • Breast Cancer


  • Verzenio (abemaciclib). Updated 10/2021. Eli Lilly and Company.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Verzenio only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Copyright 1996-2023 Revision date: December 21, 2022.

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