On September 13, the U.S. Food and Drug Administration (FDA) issued a drug safety communication warning that palbociclib, ribociclib, and abemaciclib—used to treat some patients with advanced breast cancer—may cause rare but severe inflammation of the lungs. The agency approved new warnings about this risk to the prescribing information and patient package insert for the entire class of these cyclin-dependent kinase 4/6 (CDK4/6) inhibitors. The overall benefit of CDK4/6 inhibitors still outweighs the risks when used as prescribed.
CDK4/6 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 approved palbociclib in 2015 and both ribociclib and abemaciclib in 2017. CDK4/6 inhibitors have been shown to improve progression-free survival.
According to the FDA, patients should notify their health-care professional right away if they have any new or worsening symptoms involving their lungs, as they may indicate a rare but life-threatening condition. Symptoms to watch for include difficulty or discomfort with breathing and shortness of breath while at rest or with low activity.
Specific risk factors to determine how likely it is that a person will experience severe lung inflammation when taking palbociclib, ribociclib, and abemaciclib have not been identified.
Health-care professionals should monitor patients regularly for pulmonary symptoms indicative of interstitial lung disease and/or pneumonitis, recommended the FDA. 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. The agency recommends interrupting CDK4/6 inhibitor treatment in patients who have new or worsening respiratory symptoms and permanently discontinuing treatment in patients with severe interstitial lung disease and/or pneumonitis.
The FDA reviewed CDK4/6 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. Across the entire drug class, there were reports of serious cases, including fatalities.
Read more about the safety communication at www.fda.gov/drugs/drug-safety-and-availability/fda-warns-about-rare-severe-lung-inflammation-ibrance-kisqali-and-verzenio-breast-cancer. ■
