On Sept. 13, 2019, the U.S. Food and Drug Administration (FDA) released a statement warning that Ibrance (chemical name: palbociclib), Kisqali (chemical name: ribociclib), and Verzenio (chemical name: abemaciclib) may cause rare but severe inflammation in the lungs.
Ibrance, Kisqali, and Verzenio are used to treat advanced-stage or metastatic hormone-receptor-positive, HER2-negative breast cancer.
Advanced-stage breast cancer is breast cancer that has spread to tissue near the breast. Metastatic breast cancer is breast cancer that has spread to parts of the body away from the breast, such as the bones or liver. Metastatic breast cancer is considered advanced-stage disease.
About Ibrance, Kisqali, and Verzenio
Ibrance, Kisqali, and Verzenio are cyclin-dependent kinase 4/6 inhibitors, commonly called CDK4/6 inhibitors. A kinase is a type of protein in the body that helps control cell division. CDK4/6 inhibitors work by stopping cancer cells from dividing and growing.
Ibrance, Kisqali, and Verzenio are used in combination with a type of hormonal therapy called an aromatase inhibitor as the first hormonal therapy to treat advanced-stage or metastatic, hormone-receptor-positive, HER2-negative breast cancer in postmenopausal women. Arimidex (chemical name: anastrozole), Aromasin (chemical name: exemestane), and Femara (chemical name: letrozole) are aromatase inhibitors.
Ibrance, Kisqali, and Verzenio also are used in combination with the hormonal therapy Faslodex (chemical name: fulvestrant) to treat advanced-stage or metastatic hormone-receptor-positive, HER2-negative breast cancer that has grown while being treated with a different hormonal therapy, in postmenopausal women.
Ibrance also may be used to treat men diagnosed with advanced-stage or metastatic hormone-receptor-positive, HER2-negative breast cancer.
Kisqali also may be used to treat premenopausal and perimenopausal women. Premenopausal and perimenopausal women treated with Kisqali also should be treated with a luteinizing hormone-releasing hormone agonist, such as Zoladex (chemical name: goserelin), to suppress ovarian function.
Verzenio also may be used alone to treat men or women diagnosed with hormone-receptor-positive, HER2-negative metastatic or advanced-stage breast cancer if the cancer has grown after hormonal therapy treatment and earlier chemotherapy for metastatic disease.
All three CDK4/6 inhibitors are pills taken by mouth.
About the FDA warning
The FDA said that its experts reviewed results from completed and ongoing studies on CDK4/6 inhibitors and found a link between the medicines and rare but severe lung inflammation.
The agency said that warnings have been added to the medicines’ packages. People diagnosed with breast cancer taking a CDK4/6 inhibitor should be monitored for symptoms of pneumonia or interstitial lung disease. Interstitial lung disease describes a large group of conditions that cause scarring of the lungs. The scarring makes the lungs stiff, which makes it difficult to breathe.
The FDA advised people being treated with a CDK4/6 inhibitor to contact their doctors right away if they have any new or worsening lung symptoms, including:
- difficulty breathing
- discomfort when breathing
- shortness of breath while resting or doing an activity that requires little exertion
The FDA emphasized that, “The overall benefit of CDK4/6 inhibitors is still greater than the risks when used as prescribed,” and that people should not stop taking a CDK4/6 inhibitor without talking to their doctor.
We don’t yet know the factors that make someone more likely to develop severe lung disease while taking a CDK4/6 inhibitor.
What this means for you
If you’ve been diagnosed with advanced-stage or metastatic hormone-receptor-positive, HER2-negative breast cancer and are being treated with Ibrance, Kisqali, or Verzenio, it makes sense to talk to your doctor about the FDA warning. Ask how you will be monitored for lung inflammation. You also may want to talk to your doctor about any symptoms that you should watch out for.
Editor’s Note: On Oct. 12, 2021, the FDA approved Verzenio in combination with either tamoxifen or an aromatase inhibitor after surgery to treat early-stage hormone-receptor-positive HER2-negative node-positive breast cancer with a high risk of recurrence (the cancer coming back) and a Ki-67 score of 20% or higher. Node-positive means cancer cells have been found in one or more lymph nodes. Ki-67 is a protein in cells that increases as they prepare to divide into new cells. A staining process can measure the percentage of tumor cells that are positive for Ki-67. The more positive cells there are, the more quickly they are dividing and forming new cells.
Written by: Jamie DePolo, senior editor
Reviewed by: Brian Wojciechowski, M.D., medical adviser
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