FDA issues warning for CDK 4/6 inhibitors


The Food and Drug Administration is warning that the entire class of the cyclin-dependent kinase 4/6 (CDK 4/6) inhibitors used to treat advanced breast cancer may cause rare but severe inflammation of the lungs.

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“We reviewed CDK 4/6 inhibitors cases from completed and ongoing clinical trials undertaken by manufacturers and their postmarket safety databases that described specific types of inflammation of the lungs, called interstitial lung disease and pneumonitis. Across the entire drug class, there were reports of serious cases, including fatalities,” the FDA said in a press statement.

The overall benefit of CDK 4/6 inhibitors, however, is still greater than the risks when used as prescribed, the agency said.

CDK 4/6 inhibitors are used in combination with hormone therapies to treat adults with hormone receptor–positive, human epidermal growth factor 2–negative advanced or metastatic breast cancer that has spread to other parts of the body. The FDA approved the CDK 4/6 inhibitors palbociclib (Ibrance) in 2015 and ribociclib (Kisqali) and abemaciclib (Verzenio) in 2017, based on improvements in progression-free survival.

Health care professionals should monitor patients regularly for pulmonary symptoms indicative of interstitial lung disease and/or pneumonitis. Signs and symptoms may include hypoxia, cough, dyspnea, or interstitial infiltrates on radiologic exams in patients in whom infectious, neoplastic, and other causes have been excluded. Interrupt CDK 4/6 inhibitor treatment in patients who have new or worsening respiratory symptoms, and permanently discontinue treatment in patients with severe interstitial lung disease and/or pneumonitis, the FDA said.

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