Verzenio

Verzenio (abemaciclib) is an oral targeted therapy used to treat hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer in adults. It belongs to a class of drugs called CDK4/6 inhibitors (cyclin-dependent kinase 4 and 6 inhibitors), which work by blocking enzymes that drive cancer cell growth and division.

Verzenio is used in five settings:

• With endocrine therapy (tamoxifen or an aromatase inhibitor) as adjuvant treatment for node-positive early breast cancer at high risk of coming back
• With an aromatase inhibitor as the first endocrine-based therapy for advanced or metastatic breast cancer
• With fulvestrant for advanced or metastatic breast cancer that has progressed after endocrine therapy
• With imlunestrant for estrogen receptor (ER)-positive, HER2-negative, estrogen receptor-1 (ESR1)-mutated advanced or metastatic breast cancer that has progressed after at least 1 line of endocrine therapy. Your healthcare provider will use an FDA-authorized blood test to check for an ESR1 mutation before you start this combination.
• Alone (monotherapy) for advanced or metastatic breast cancer that has progressed after endocrine therapy and prior chemotherapy in the metastatic setting

Unlike some other CDK4/6 inhibitors, Verzenio is taken twice daily, every day, without a break. It is taken orally with or without food. Verzenio is available as 50 mg, 100 mg, 150 mg, and 200 mg tablets.

Verzenio received FDA approval on September 28, 2017. Its use in combination with imlunestrant (Inluriyo) was approved on September 18, 2026. Verzenio is marketed by Lilly USA, LLC. There is no generic.

Take Verzenio exactly as your healthcare provider tells you to. Follow all directions on your Verzenio Patient Information. Your healthcare provider may change your dose if needed. Do not stop taking Verzenio or change the dose without talking to your healthcare provider.

• Verzenio is usually taken 2 times a day, at about the same times every day.
• Take with or without food.
• Swallow the tablets whole. Do not chew, crush, or split them.
• Do not take tablets that are broken, cracked, or damaged.

When Verzenio is used with fulvestrant, tamoxifen, imlunestrant, or an aromatase inhibitor, also read the Patient Information or Medication Guide for that medicine.

Monitoring during Verzenio treatment

Your healthcare provider will do regular blood tests during Verzenio treatment to check for side effects.

Blood count monitoring (for neutropenia)

• Before starting Verzenio
• Every 2 weeks for the first 2 months
• Monthly for the next 2 months
• As clinically indicated after that

Liver function monitoring (for hepatotoxicity)

• Before starting Verzenio
• Every 2 weeks for the first 2 months
• Monthly for the next 2 months
• As clinically indicated after that

Tell your healthcare provider right away if you develop symptoms of liver problems (extreme tiredness, pain in the upper right abdomen, loss of appetite, or easy bruising or bleeding) or lung problems (new or worsening shortness of breath, cough, or chest pain).

Before taking Verzenio, tell your healthcare provider about all of your medical conditions, including if you:

• have fever, chills, or any other signs of an infection
• have a history of blood clots in your veins
• have lung or breathing problems
• have liver or kidney problems
• are pregnant or plan to become pregnant
• are breastfeeding or plan to breastfeed

Especially tell your healthcare provider if you take a medicine that contains ketoconazole. Know the medicines you take. Keep a list of them to show your healthcare provider or pharmacist when you get a new medicine.

Pregnancy

Verzenio can harm your unborn baby. Females who can become pregnant:

• Your healthcare provider will do a pregnancy test before you start treatment with Verzenio.
• Use effective birth control (contraception) during treatment with Verzenio and for 3 weeks after the last dose.
• If you are taking Verzenio in combination with another medicine, your healthcare provider will tell you how long you should use birth control.
• Tell your healthcare provider right away if you become pregnant or think you are pregnant during treatment with Verzenio.

Verzenio may affect a man's ability to father a child.

Breastfeeding

It is not known if Verzenio passes into your breast milk. Do not breastfeed during treatment with Verzenio and for at least 3 weeks after the last dose. If you are taking Verzenio in combination with another medicine, your healthcare provider will tell you how long you should not breastfeed.

Common side effects

The most common side effects of Verzenio (occurring in 20% or more of patients across clinical trials) include:

• diarrhea
• infections
• low white blood cell counts (neutropenia and leukopenia)
• tiredness (fatigue)
• stomach area (abdominal) pain
• nausea
• low red blood cell counts (anemia)
• vomiting
• decreased appetite
• headache
• hair thinning or hair loss (alopecia)
• low platelet count (thrombocytopenia).

Diarrhea is the most common side effect, occurring in 81% to 90% of patients across clinical trials, and is severe (Grade 3) in 8% to 20%. It usually starts in the first month of treatment, most often within the first 6 to 8 days.

Most side effects are managed with supportive care, temporarily stopping treatment, or lowering the dose. In the EMBER-3 trial of Verzenio with imlunestrant, nausea was more common in patients aged 65 years and older (59%) than in younger patients (44%).

Verzenio can cause an increase in a blood test called serum creatinine, usually within the first month of treatment. This does not mean your kidneys are damaged. It happens because Verzenio blocks the way the kidneys release creatinine into the urine, and levels return to normal after treatment stops. Your healthcare provider may use other blood tests, such as cystatin C or BUN, to check your kidney function during treatment.

Verzenio may cause fertility problems in males, which may affect the ability to father a child.

Serious side effects and warnings

Verzenio (abemaciclib) may cause the following serious side effects:

Diarrhea

Diarrhea is common with Verzenio treatment and may sometimes be severe. Diarrhea may lead to loss of large amounts of fluid and salt, causing you to develop dehydration. The most common time to develop diarrhea is during the first month of Verzenio treatment. If you develop diarrhea during treatment with Verzenio, your healthcare provider may tell you to temporarily stop taking Verzenio, stop your treatment, or decrease your dose.

If you develop any loose stools, start taking an antidiarrheal medicine (such as loperamide), drink more fluids, and tell your healthcare provider right away.

Low white blood cell counts (neutropenia)

Low white blood cell counts are common during treatment with Verzenio and may cause serious infections that can lead to death. Your healthcare provider should check your white blood cell counts before and during treatment. If you develop low white blood cell counts during treatment with Verzenio, your healthcare provider may tell you to temporarily stop taking Verzenio, decrease your dose, or wait before starting your next month of treatment.

Tell your healthcare provider right away if you develop signs or symptoms of an infection, such as fever and chills.

Lung problems

Verzenio may cause severe or life-threatening inflammation of the lungs during treatment that can lead to death. If you develop lung problems during treatment with Verzenio, your healthcare provider may tell you to temporarily stop taking Verzenio, decrease your dose, or stop your treatment. Tell your healthcare provider right away if you develop any new or worsening signs or symptoms, including:

• trouble breathing or shortness of breath
• cough with or without mucus
• chest pain

Liver problems

Verzenio can cause serious liver problems. Your healthcare provider should do blood tests to check your liver before and during treatment with Verzenio. If you develop liver problems during treatment with Verzenio, your healthcare provider may reduce your dose or stop your treatment. Tell your healthcare provider right away if you develop signs and symptoms of liver problems, such as:

• feeling very tired
• pain on the upper right side of your stomach area (abdomen)
• loss of appetite
• bleeding or bruising more easily than normal

Blood clots in your veins, or in the arteries of your lungs

Verzenio may cause serious blood clots that have led to death. If you develop blood clots during treatment with Verzenio, your healthcare provider may tell you to temporarily stop taking Verzenio. Tell your healthcare provider right away if you develop signs or symptoms of a blood clot, such as:

• pain or swelling in your arms or legs
• shortness of breath
• chest pain
• rapid breathing
• rapid heart rate

These are not all of the possible side effects of Verzenio. For more information, ask your healthcare provider or pharmacist. Call your healthcare provider for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Verzenio (abemaciclib) is a targeted therapy that blocks two enzymes, cyclin-dependent kinases 4 and 6 (CDK4 and CDK6). In estrogen receptor-positive breast cancer cells, these enzymes help switch on a protein called retinoblastoma protein (Rb), which allows cells to move through the cell cycle and divide. By blocking CDK4 and CDK6, Verzenio stops cancer cells from moving from the growth phase (G1) into the phase where they copy their DNA (S phase). This causes the cancer cells to stop dividing or die.

Verzenio belongs to a drug class called CDK4/6 inhibitors, also known as kinase inhibitors.

The table below summarizes the main results from the clinical trials that support each use of Verzenio.

HR = hazard ratio. A hazard ratio below 1 means a lower risk of the cancer growing, coming back, or death with Verzenio.

Standard doses

• With fulvestrant, tamoxifen, imlunestrant, or an aromatase inhibitor: 150 mg twice daily
• As monotherapy: 200 mg twice daily

Take at approximately the same times each day, with or without food. Swallow tablets whole. Do not chew, crush, or split them, and do not take a tablet that is broken, cracked, or damaged.

Premenopausal and perimenopausal women and men who take Verzenio with an aromatase inhibitor, imlunestrant, or fulvestrant should also receive a gonadotropin-releasing hormone (GnRH) agonist.

How long to take it

• Early breast cancer: For 2 years, or until the cancer returns or side effects become unacceptable
• Advanced or metastatic breast cancer: Until the cancer progresses or side effects become unacceptable

Dose reductions for side effects

Your doctor may lower your dose if side effects become difficult to manage. The dose is lowered in 50 mg steps. Verzenio cannot be reduced below 50 mg twice daily. If this dose is still not tolerated, treatment is stopped.

The general approach for managing side effects is:

• Diarrhea: At the first sign of loose stools, start an antidiarrheal medicine (such as loperamide) and increase fluid intake. If moderate (Grade 2) diarrhea does not improve within 24 hours, or diarrhea is severe or needs a hospital stay, your dose will be paused and possibly reduced.
• Low blood cell counts (neutropenia): Blood counts are checked before treatment starts, every 2 weeks for the first 2 months, then monthly for 2 months. Dose pauses or reductions are made based on severity.
• Liver problems: Liver function tests follow the same monitoring schedule as blood counts. Severe liver enzyme increases may require permanent discontinuation.
• Lung inflammation (ILD/pneumonitis): Grade 3 or 4 cases require permanent discontinuation.
• Blood clots: In early breast cancer, treatment is paused for a clot of any grade until you are clinically stable. In advanced breast cancer, minor clots (Grade 1 or 2) do not require a dose change.

Dose changes for drug interactions

• Ketoconazole: Avoid.
• Other strong CYP3A inhibitors (for example, clarithromycin): Reduce Verzenio to 100 mg twice daily, or to 50 mg twice daily if your dose has already been lowered to 100 mg twice daily because of side effects.
• Moderate CYP3A inhibitors (for example, verapamil and diltiazem): Your healthcare provider will monitor you for side effects and may lower your dose in 50 mg steps if needed.
• Strong or moderate CYP3A inducers (for example, rifampin, efavirenz, bosentan, and modafinil): Avoid. These lower Verzenio levels and may make it work less well.

Severe liver impairment

Patients with severe liver impairment (Child-Pugh C) should take Verzenio once daily instead of twice daily.

If you miss a dose of Verzenio, skip the missed dose and take your next dose at your regular time. If you vomit after taking a dose, do not take another dose. Take your next dose at your regular time. Do not take 2 doses of Verzenio at the same time to make up for a missed dose.

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Verzenio may affect the way other medicines work, and other medicines may affect how Verzenio works, causing serious side effects.

Verzenio is broken down mainly by the liver enzyme CYP3A4. Medicines that affect CYP3A can significantly change Verzenio blood levels and either increase the risk of side effects or reduce how well it works.

Avoid completely

• Ketoconazole. This is predicted to increase Verzenio levels by up to 16-fold.
• Strong or moderate CYP3A inducers, such as rifampin, efavirenz, bosentan, and modafinil. These reduce Verzenio levels.
• Grapefruit and grapefruit-containing products. These may increase Verzenio levels.

May need a lower Verzenio dose

• Other strong CYP3A inhibitors, such as clarithromycin
• Moderate CYP3A inhibitors, such as verapamil and diltiazem

This list is not complete. Other drugs may affect Verzenio, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Store Verzenio at room temperature between 68°F and 77°F (20°C and 25°C). Short periods between 59°F and 86°F (15°C and 30°C) are allowed. Keep out of the reach of children.

Verzenio (abemaciclib) is marketed by Lilly USA, LLC, Indianapolis, IN 46285, USA. For more information, go to www.verzenio.com or call 1-800-545-5979.

Active ingredient: abemaciclib

Inactive ingredients: microcrystalline cellulose 102, microcrystalline cellulose 101, lactose monohydrate, croscarmellose sodium, sodium stearyl fumarate, and silicon dioxide.

Color mixture ingredients: polyvinyl alcohol, titanium dioxide, polyethylene glycol, talc, iron oxide yellow, and iron oxide red.

Verzenio is available as 50 mg, 100 mg, 150 mg, and 200 mg tablets, supplied in blister packs of 14 tablets (a 7-day supply). Verzenio (abemaciclib) is only available as a branded medicine. There is no generic.