Guideline: FDA issues warning on CDK inhibitors

This article is most relevant for:
People currently taking a CDK inhibitor

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Checked Breast cancer survivors

Checked ER/PR +

Checked Men with breast cancer

Checked Metastatic cancer

Checked People with a genetic mutation linked to cancer risk

Checked Women under 45

Checked Women over 45

Checked Special populations: People taking CDK inhibitors

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Research Timeline: Post Approval

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The U.S. Food and Drug Administration issued a safety alert for CDK inhibitors, including Ibrance (palbociclib), Kisqali (ribociclib), and Verzenio (abemaciclib). (9/24/19)


At a glance Questions for your doctor
Findings                              Resources and reference             


This study is about:

The U.S. Food and Drug Administration’s (FDA) safety alert warning that Ibrance (palbociclib), Kisqali (ribociclib), and Verzenio (abemaciclib) may cause a rare but severe inflammation of the lungs.

Why is this study important?

The FDA approved Ibrance in 2015, and both Kisqali and Verzenio in 2017 to treat some patients with advanced breast cancer. These drugs, called CDK 4/6 inhibitors have been shown to significantly improve the amount of time a cancer does not grow and the patient is alive.  However, in some patients they may cause rare but severe lung inflammation

FDA findings:

CDK 4/6 inhibitors are a class of prescription medicines that are used in combination with hormone therapies to treat adults with hormone receptor-positive, HER2-negative advanced or metastatic breast cancer.

The FDA reviewed cases of lung disease associated with use of CDK 4/6 inhibitors.  Cases were identified from both ongoing and completed clinical trials. Cases were also identified from the FDA’s drug safety database.

The FDA found that, although rare, there were serious cases and/or deaths with Ibrance (palbociclib), Verzenio (abemaciclib), and Kisqali (ribociclib).

  • Across clinical trials of these three CDK 4/6 inhibitors, 1 to 3 percent of patients had lung inflammation of any grade.
    • Less than 1 percent of these patients had fatal outcomes.
  • Among patients who developed lung inflammation, including fatal cases, there were patients who had no risk factors for lung disease, but some patients had at least one risk factor.


The FDA recommends that anyone taking these CDK inhibitors notify their health care provider if they have any new or worsening symptoms involving their lungs.

Symptoms to watch for include:

  • Difficulty or discomfort with breathing
  • Shortness of breath while at rest or with low activity

What does this mean for me?

Rarely, CDK 4/6 inhibitors can cause severe lung inflammation. However, the benefits of taking these medicines may outweigh this risk. The FDA is urging patients to not stop taking a CDK 4/6 inhibitors without first talking to their health care provider. 

It is important to know:

  • All medicines have side effects even when used correctly as prescribed.
  • People respond differently to all medicines depending on their health, the diseases they have, genetic factors, other medicines they are taking, and many other factors.

Experts do not yet know the factors that make a patient high-risk for severe lung inflammation when taking Ibrance, Kisqali, or Verzenio.

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Posted 9/24/19

Questions To Ask Your Health Care Provider

  • Is it safe for me to continue to take my medication (CDK4/6 inhibitors)?
  • I am worried I am risk for lung disease, should I continue to take my medication (CDK 4/6 inhibitor)?
  • Are there other medications that are as effective for me as a CDK 4/6 inhibitor?
  • What signs or symptoms of lung disease should I be looking for?
  • Should I have a chest XRAY or other scan for lung disease?

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