Your Guide to Verzenio for Metastatic Breast Cancer

Overview of Verzenio

Verzenio (abemaciclib) is a prescription medicine used to treat a type of breast cancer called HR+/HER2- (hormone receptor-positive/human epidermal growth factor receptor 2-negative) breast cancer, when it has spread (metastasized) from the breast to other parts of the body.

Metastatic breast cancer, which means the cancer has spread from the breast to other parts of the body, is also known as advanced breast cancer and typically affects the bones, lungs, liver, and brain. The National Institutes of Health estimates that there were 168,000 women in the United States living with metastatic breast cancer as of 2020.

In HR+/HER2- breast cancer, the cancer cells have hormone receptors on their surface, but do not have HER2 receptors. HR+/HER2- breast cancer accounts for 69% of all breast cancer cases, according to the National Cancer Institute.

Since the hormones estrogen and progesterone act like fuel for HR+ cancer cells, metastatic breast cancer therapy frequently involves hormone therapy with medications called aromatase inhibitors and fulvestrant. Aromatase inhibitors work by reducing the estrogen available to tumor cells, while fulvestrant works by blocking estrogen from binding to cancer cells, explains the National Cancer Institute.

Verzenio is prescribed in combination with an aromatase inhibitor, in combination with fulvestrant, or by itself. It works by blocking specific proteins responsible for the growth of cancer cells.

The U.S. Food and Drug Administration (FDA) approved Verzenio to be given in combination with fulvestrant or alone for the treatment of metastatic HR+/HER2- breast cancer in September 2017. In February 2018, the FDA approved the use of Verzenio in combination with an aromatase inhibitor as an initial treatment for metastatic HR+/HER2- breast cancer.

Verzenio is also used to treat early-stage HR+/HER2- breast cancer along with hormone therapy.

Verzenio can be taken by adult patients with HR+/HER2- advanced or metastatic breast cancer. It is prescribed in three situations:

• When metastatic breast cancer has just been diagnosed (Verzenio taken with an aromatase inhibitor)

• If metastatic breast cancer progresses after initial hormone therapy (Verzenio taken with fulvestrant)

• If metastatic breast cancer progresses after both hormone therapy and chemotherapy (Verzenio taken by itself)

In healthy cells, specific proteins called CDK4 and CDK6 help control how fast cells grow. Along with hormones like estrogen and progesterone, the proteins CDK4 (cyclin-dependent kinase 4) and CDK6 (cyclin-dependent kinase 6) play an important role in the growth and division process of normal cells.

In HR+/HER2-negative breast cancer, CDK4 and CDK6 proteins become overactive, causing the cancer cells to grow and divide uncontrollably, which makes the tumor grow. This can lead to cancer cells spreading to other parts of the body.

Verzenio works by blocking specific CDK4 and CDK6 proteins when cancer cells are about to divide. This helps to stop the growth of cancer cells, so they may eventually die.

Verzenio exists in the form of tablets with different strengths: 50 milligrams (mg), 100 mg, 150 mg and 200 mg. Your doctor will prescribe one of these doses based on other medications you may be taking and how you tolerate the drug.

If you are taking an aromatase inhibitor or fulvestrant, the recommended dose for Verzenio is a 150 mg tablet twice a day, one in the morning and one at night, as close to 12 hours apart.

If you are taking Verzenio by itself, the recommended dose is a 200 mg tablet twice a day, one in the morning and one at night, as close to 12 hours apart.

You can take Verzenio with or without food, but avoid food or drink containing grapefruit. Do not chew, crush or split the pill.

The approval of Verzenio in combination with an aromatase inhibitor was based on the MONARCH 3 study, published in npj Breast Cancer. In the study, 493 postmenopausal women with HR+/HER2- metastatic breast cancer were randomly assigned to receive 150 mg of Verzenio or placebo twice daily, plus an aromatase inhibitor (letrozole or anastrozole, as decided by the physician). Patients who took Verzenio had longer progression-free survival (28.2 months) compared to those who took placebo (14.8 months).

The approval of Verzenio in combination with fulvestrant was based on the MONARCH 2 study, published in the Journal of Clinical Oncology. The study recruited 669 women with HR+/HER2- metastatic breast cancer that had continued to progress despite hormone therapy. Participants were randomly assigned to receive 150 mg of Verzenio or placebo twice daily, plus fulvestrant. Patients who took Verzenio had longer progression-free survival (16.4 months) compared to those who took placebo (9.3 months).

Finally, the approval of Verzenio as a monotherapy was based on the MONARCH 1 study, published in Clinical Cancer Research. The study recruited women with HR+/HER2- metastatic breast cancer that had continued to progress despite hormone therapy and chemotherapy. In the study, 132 patients took 200 mg of Verzenio orally twice every day, either until their cancer worsened or until side effects from treatment became severe. In the study, 19.7% of the patients had a positive response to the treatment.

Based on evidence from clinical trials, the FDA deemed the benefits of Verzenio to outweigh the risks for people with HR+/HER2-metastatic breast cancer. However, side effects may occur, some of them serious.

The most common side effects of Verzenio (occurring in more than 20% of patients) are:

• Abdominal pain

• A decrease in a type of white blood cells called neutrophils (neutropenia)

• Decreased appetite

• Decrease in the total number of white blood cells (leukopenia)

• Diarrhea

• Fatigue

• Hair thinning or hair loss (alopecia)

• Headache

• Infections

• Low blood platelet count (thrombocytopenia)

• Low red blood cell count (anemia)

• Nausea

• Vomiting