What to Know About Verzenio (Abemaciclib) for Early Breast Cancer

There are many types of breast cancer. Hormone receptor-positive/human epidermal growth factor receptor 2-negative breast cancer, also known as HR+/HER2- breast cancer, is the most common.

There are also several breast cancer stages. In most cases, the earlier a cancer is found, the easier it is to treat. This is called early breast cancer (EBC). Thankfully, more than 90% of breast cancers are found in an early stage. 

While this is good news, some cases of EBC are more aggressive than others. Even after receiving treatments such as surgery or chemotherapy, some people are at a higher risk of their cancer coming back.

If you’ve been diagnosed with HR+/HER2- EBC and you are in this higher-risk category, you may be wondering if treatments are available to increase your chances of living cancer-free. Verzenio (abemaciclib) is one option your cancer specialist may recommend. It's the first medication of its kind to be approved for EBC.

Here, we’ll cover how Verzenio works, what it treats, and what side effects to expect.

What is Verzenio?

Verzenio is an oral medication used to treat people with HR+/HER2- EBC who are at higher risk of their cancer coming back after surgery. It’s also approved to treat HR+/HER2- advanced breast cancer. Verzenio is a type of targeted therapy, which means that it targets proteins in the body that help cancer grow.

Verzenio is available in tablet form and comes as 50 mg, 100 mg, 150 mg, and 200 mg tablets. In most cases, the recommended starting dosage is 150 mg taken by mouth twice a day. If Verzenio is taken by itself, however, the recommended starting dose is 200 mg by mouth twice a day.

For EBC, Verzenio is often taken in combination with a hormone therapy medication. Tamoxifen (Soltamox) or an aromatase inhibitor like anastrozole (Arimidex) are two common choices.

How does Verzenio work?

Verzenio works by blocking proteins called cyclin-dependent kinases (CDKs) — specifically CDK4 and CDK6. Other common CDK4 and CDK6 inhibitors are Ibrance (palbociclib) and Kisqali (ribociclib).

Normally, CDKs help cells divide. When CDK4 and CDK6 are blocked in hormone-receptor positive (HR+) breast cancer, cells stop dividing. This prevents the cancer from growing.

In the case of EBC, this means that Verzenio may reduce the chances of the cancer coming back. In advanced breast cancer, it helps reduce the size of the tumor.

Verzenio FDA approval history

Verzenio was initially FDA approved in 2017. It has obtained additional approved uses since then. 

Verzenio’s first approval was for HR+/HER2- breast cancer that is advanced or has spread (metastasized) to other organs. It can be used by itself or in combination with other hormone therapies, depending on the situation.

In 2021, Verzenio was approved to treat EBC in people who have a high risk of their cancer coming back. At that time, it was only approved to treat people whose breast cancer also had a Ki-67 score of 20% or higher. A high score indicates that breast cancer cells are multiplying quickly. This suggests a higher risk of cancer coming back.

In March 2023, the FDA expanded Verzenio’s approval for EBC. It can now treat people with high-risk EBC regardless of their Ki-67 score. This allowed more people to qualify to receive treatment with Verzenio.

How effective is Verzenio for early breast cancer?

Even after treatment with surgery, chemotherapy, or radiation therapy, breast cancer cells can still be left behind in the body. This raises the risk of cancer coming back. Verzenio is effective at killing EBC cells left behind after these treatments.

Verzenio was studied in a clinical trial of over 5,000 people with high risk, HR+/HER2- EBC who had received previous treatment. Some people in this study received Verzenio in combination with hormone therapy, while others received hormone therapy by itself. The study found that people who took Verzenio and hormone therapy had a 35% lower risk of their breast cancer coming back than those who only received hormone therapy. 

After 4 years, about 86% of people who took Verzenio with hormone therapy remained cancer-free. Only about 79% of people who took hormone therapy alone remained cancer-free. 

What are common Verzenio side effects?

Like all medications, Verzenio has a number of possible side effects. Verzenio’s common side effects include:

• Low red blood cell count (anemia)

• Low white blood cell count 

• Low platelet count

• Diarrhea

• Headache

• Change in appetite

• Nausea and vomiting

• Upset stomach 

• Tiredness

• Hair thinning

Are there any serious Verzenio risks or side effects?

Although having a low number of white blood cells is common with Verzenio, it may lead to a serious condition called neutropenia. Neutropenia refers to having a very low number of neutrophils — a type of white blood cell — in your body. These cells are part of your immune system.

People with neutropenia are more likely than others to develop an infection. This is why it is important to monitor for any fever or chills if you are neutropenic. You should also look out for other symptoms of infection — like sore throat, cough, shortness of breath, or skin rashes. If you’re experiencing any of these, contact a healthcare provider right away.

Verzenio may possibly cause pneumonitis or interstitial lung disease. These conditions can cause scarring or inflammation of the lungs. Contact a healthcare provider if you are experiencing symptoms such as:

• Cough

• Shortness of breath

• Chest pain

• Tiredness

• Weight loss

Verzenio may rarely lead to liver damage. Symptoms to look out for include:

• Dark urine

• Nausea and vomiting

• Upper right-side stomach pain

• Yellowing of skin and eyes (jaundice)

• New swelling in the abdomen or legs

Lastly, Verzenio is linked to a risk of blood clots. Contact your healthcare provider if you notice these symptoms in your legs or arms, especially if it’s only on one side:

• Pain

• Redness

• Swelling

• Tenderness

How to save on Verzenio

There are ways to save on Verzenio, which is only available as a brand-name medication. GoodRx can help you navigate patient assistance programs and copay savings cards to save money on your prescription.

• Save with patient assistance programs. If you’re uninsured or underinsured, you may be eligible for Verzenio’s patient assistance program, which offers the medication free of cost.

• Save with a copay savings card. If you have commercial insurance, you may be eligible to pay as little as $0 for Verzenio using a savings card from the manufacturer.

Why trust our experts?

Written by:

Sonja Jacobsen, PharmD, BCPS, BCOP

Sonja Jacobsen, PharmD, BCPS, BCOP,  is a clinical oncology pharmacy specialist currently practicing in Seattle. She has been practicing as a pharmacist since 2015 and is licensed to practice in Washington state and North Carolina.

Edited by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

Reviewed by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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