Palbociclib (Ibrance®), ribociclib (Kisqali®), and abemaciclib (Verzenio®) used to treat some patients with advanced breast cancers may cause rare but severe inflammation of the lungs, the U.S. Food and Drug Administration (FDA) announced in a drug safety communication on September 13, 2019. It approved new warnings about the risk on the prescribing information and package insert for the entire class of cyclin-dependent kinase 4/6 (CDK 4/6) inhibitor medicines. However, “the overall benefit of CDK 4/6 inhibitors is still greater than the risks when used as prescribed,” the agency wrote.

FDA recommended that providers monitor patients regularly for pulmonary symptoms indicative of interstitial lung disease (ILD) or pneumonitis, including hypoxia, cough, dyspnea, and interstitial infiltrates on radiologic exams in patients in whom infectious, neoplastic, and other causes have been excluded. For patients who have new or worsening respiratory symptoms, treatment should be interrupted. Permanently discontinue treatment in those with severe ILD or pneumonitis. 

Oncology nurses should instruct patients to notify the healthcare team if they experience any new or worsening lung symptoms, including difficulty or discomfort with breathing or shortness of breath while at rest or with low activity. If patients ask about the increased risk for lung inflammation, nurses can explain that the benefits of treatment outweigh the rare risk and that no specific risk factors for the development of lung symptoms have been identified.

Healthcare professionals and patients should report adverse events or side effects related to the use of the CDK 4/6 inhibitors to FDA’s MedWatch Reporting System or by calling 800-FDA-1088.