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FDA Approves Verzenio (Abemaciclib) for Early Breast Cancer

Ross Phan

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This post was originally published on the GoodRx website.

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Key takeaways:

  • Many people treated for HR+/HER2- early breast cancer (EBC) will live cancer-free. But some people have certain traits that raise the chances of their cancer coming back in the future.

  • The FDA recently approved Verzenio (abemaciclib) to treat certain people with high-risk HR+/HER2- EBC.

  • Before this approval, Verzenio was already FDA-approved to treat advanced breast cancer.

Breast cancer in women is very common. In 2021, breast cancer is estimated to affect almost 300,000 U.S. women. Additionally, this year, it’s estimated that breast cancer will cause over 43,000 deaths in the U.S. 

Out of all types of breast cancer, a type called HR+/HER2- is the most common. It makes up close to 70% of all breast cancers. Plus, over 90% of breast cancer cases are found in an early stage and called early breast cancer (EBC). 

In October 2021, the FDA added a new approval for Verzenio (abemaciclib). Previously, Verzenio was used to treat advanced HR+/HER2- breast cancers. It is now also approved to treat people with HR+/HER2- EBC who are at high risk of their cancer coming back after surgery. Verzenio is the first medication of its class to be approved for EBC. 

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

What is Verzenio?

Verzenio is a medication used to treat breast cancer. There are many different types of medications that can treat breast cancer. Verzenio is a type of targeted therapy, which means that it targets proteins in the body that help cancer grow.

How does Verzenio work?

Verzenio works by blocking proteins called cyclin-dependent kinases (CDKs), specifically CDK4 and CDK6. Other CDK4 and CDK6 inhibitors you might have heard of are Ibrance (palbociclib) and Kisqali (ribociclib).

Normally, CDKs are proteins that help cells divide. When CDK4 and CDK6 are blocked in hormone-receptor positive (HR+) breast cancer, cells stop dividing. 

That means in advanced breast cancer, taking a targeted therapy like Verzenio would prevent cancer cells from multiplying and reduce the size of tumors. In early breast cancer, taking Verzenio may prevent cancer cells from multiplying and reduce the chance of the cancer coming back.

What does Verzenio treat?

First, let’s recap the main receptors in breast cancer. Receptors (chemical binding sites) are proteins that bind to substances in the body. But what does this mean?

  • Hormone receptors (HR) include both estrogen receptors (ER) and progesterone receptors (PR). Estrogen and progesterone are fuel sources that can make breast cancer grow. If these hormone receptors are present on breast cancer cells, it’s called HR+ breast cancer.

  • Human epidermal growth factor receptor 2 (HER2) is a protein that can help breast cells grow. A high level HER2 is linked to abnormal changes in breast cells that may lead to a more aggressive cancer. If a breast cancer has a lot of HER2, it’s called HER2+ breast cancer. If breast cancer cells have little or no HER2, it’s called HER2-.

Verzenio treats HR+/HER2- breast cancer. In cases of EBC, the medication is used with endocrine (or hormone) therapy after surgery to prevent tumors from coming back.

Endocrine therapy works by blocking the effects of estrogen — a breast cancer fuel source — on hormone receptors in breast tissue. 

There are two types of endocrine therapies that can be used with Verzenio in HR+/HER2- EBC: 

1) Tamoxifen works by blocking the effects of estrogen in breast tissue. Tamoxifen belongs to a class of medications called selective estrogen receptor modulators (SERMs). It blocks estrogen in breast tissue while acting like estrogen in other tissues like bone. 

2) Aromatase inhibitors work by lowering the amount of estrogen. These include Arimidex (anastrozole) or Femara (letrozole). 

It’s common to use hormone therapies for 5 to 10 years after surgery to prevent breast cancer from coming back. Tap or click here for a detailed review of these medications.

What is HR+/HER2- early stage breast cancer?

EBC means that the cancer has not spread to other parts of the body. Since the cancer is only in one location, it can often be removed with surgery. Surgery can also be combined with radiation or chemotherapy to treat the cancer and reduce the risk of it coming back.

But remember, HR+ EBC means that a tumor has either estrogen or progesterone receptors. That means after surgery, tumors that are HR+ can also be treated with endocrine therapy — tamoxifen, anastrozole, or letrozole. But cancers that are HER2- can’t be treated with targeted HER2 medications. 

Many people with HR+/HER2- EBC will live cancer-free for most or all of their lives after receiving treatment. But, sadly, up to 20% of people treated for HR+/HER2- EBC may have their breast cancer come back. Some people have high-risk characteristics that raise the chances of the cancer coming back. More on this next.

What worsens the risk of HR+/HER2- early breast cancer getting worse?

Some people with HR+/HER2- EBC are at high risk of their cancer coming back. People at higher risk have some of the following traits:

  • Large tumor size: If the tumor is at least 5 cm or larger, there is a higher risk of the cancer coming back.

  • Grade 3 breast cancer: There are three grades of breast cancer that describe how abnormal cells look under a microscope. Grade 3 is a high-grade tumor. High-grade tumor cells don’t look normal, and they grow quickly. Cancer grades are different from cancer stages.

  • Lymph node involvement: Lymph nodes are small structures in the immune system — the part of the body that helps fight infections. If breast cancer cells have spread to your lymph nodes, you’re at a higher risk of the cancer coming back.

  • High Ki-67 score (20% or higher): Ki-67 is a protein that is found in dividing cells. If 20% or more of your cancer cells have Ki-67, then breast cancer cells are multiplying quickly. A high Ki-67 score is linked to a high risk of the cancer coming back.

If your HR+/HER2- EBC has some of the characteristics listed above, you may be eligible to receive Verzenio. 

Was Verzenio already FDA approved?

Yes, Verzenio was initially approved in 2017. The first approval was for HR+/HER2- breast cancer that is advanced or has spread (metastasized) to other organs. In more advanced cancers, the way Verzenio is used depends on what treatments you have already received.  Verzenio can be used:

  • In combination with endocrine therapy, if you have not received any breast cancer therapy: Verzenio can be used with an aromatase inhibitor in HR+/HER2- advanced or metastatic breast cancer that has never been treated.

  • In combination with fulvestrant, after treatment with endocrine therapy: Verzenio can be used with fulvestrant in HR2+/HER2- advanced or metastatic breast cancer that worsens after taking endocrine therapy.

  • By itself, after treatment with both endocrine therapy and prior chemotherapy: If HR+/HER2- breast cancer has spread after being treated with endocrine therapy and prior chemotherapy, then Verzenio can be used alone.

Verzenio is available as 50 mg, 100 mg, 150 mg, and 200 mg tablets. In most cases, the recommended starting dose is 150 mg by mouth 2 times a day. If Verzenio is taken by itself, however, the recommended starting dose is 200 mg by mouth 2 times a day.

What does the new clinical trial data suggest?

A study called the monarchE trial provided information that showed Verzenio can be used for this new purpose. 

In this study, people with high-risk HR+/HER- EBC were given either endocrine therapy alone or endocrine therapy with Verzenio. Results suggest that people with high-risk HR+/HER2- EBC can benefit from the addition of Verzenio to standard endocrine therapy. 

The combination treatment lowered the risk of a new cancer event by 25%. This means a lower risk of the cancer coming back, any new cancer developing, or death. 

What are Verzenio’s common side effects?

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

  • Low number of red blood cells (anemia)

  • Low number of white blood cells (WBCs)

  • Low number of platelets in your blood

  • Diarrhea

  • Headache

  • Change in appetite

  • Nausea and vomiting

  • Upset stomach

  • Tiredness

  • Hair thinning

Are there any serious risks or side effects?

Although having a low number of WBCs 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 WBC — in your body. WBCs are part of your immune system. 

People with neutropenia are more likely than others to develop an infection. Symptoms to look out for if you are neutropenic include fever and chills, especially if you have diarrhea, burning with urination, or sore throat. If you think this is happening, 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

  • Tiredness

  • Weight loss

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

  • Dark urine

  • Nausea and vomiting

  • Upper right-sided stomach pain

  • Yellowing of skin and eyes (jaundice)

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

  • Pain

  • Redness

  • Swelling

  • Tenderness

How much does it cost?

Verzenio is a brand-name medication. Additionally, it is a limited-distribution drug that is not usually available at your local retail pharmacy. It’s usually filled at specialty pharmacies and is expensive if not covered by your insurance.

However, the manufacturer — Eli Lilly and Company — offers a support program to help with insurance copays. If cost is a concern, consider calling Eli Lilly at 1-844-837-9364.

The bottom line

The FDA recently approved an additional use for Verzenio. This medication is the first CDK 4/6 inhibitor that can be used in people with high-risk HR+/HER2- EBC to lower the chances of the cancer coming back. Although effective, Verzenio has some serious side effects. If you have any questions or concerns about Verzenio, please talk with your healthcare provider.

ABOUT THE AUTHOR:

Ross earned her doctorate in pharmacy (PharmD) at The University of Texas at Austin (UT Austin). Her years of experience practicing in various pharmacy settings also lead to multiple board certifications, including ambulatory care, geriatrics, and pharmacotherapy. She currently serves as the director of the PharmacyChecker international verification program.

Ross also founded Off Script Consults, a pharmacy consulting business. She strives to combine her passion for pharmacy, education, and writing to improve the quality of life and financial outcomes for people with chronic medical conditions, caregivers, and healthcare providers.

She particularly enjoys creating relatable and helpful content for her readers and viewers. For writing samples, please visit her Muck Rack portfolio. For videos, please visit her “Off Script Consults” YouTube channel.

Ross currently resides with her husband and two dogs in her home state of Texas to be closer to family. She also tries to find time for hobbies, which include rock climbing, running, and playing pickle ball.

Find out more about Ross via phone, e-mail, or social media (LinkedIn, TikTok, Instagram, Twitter, Facebook, and Pinterest).