The US Food and Drug Administration (FDA) issued a warning today that the commonly prescribed breast cancer therapies known as cyclin-dependent kinase 4/6 (CDK 4/6) inhibitors may cause rare but severe inflammation of the lungs. The related products include palbociclib (Ibrance, Pfizer), ribociclib (Kisqali, Novartis), and abemaciclib (Verzenio, Eli Lilly), which are approved for use in patients with hormone receptor (HR)-positive, human epidermal growth factor 2 (HER2)-negative advanced or metastatic breast cancer. Healthcare professionals are advised to monitor patients on these drugs regularly for pulmonary symptoms indicative of interstitial lung disease (ILD) and/or pneumonitis, such as hypoxia, cough, dyspnea, or interstitial infiltrates on radiologic exams in patients. Professionals should interrupt CDK 4/6 inhibitor treatment in patients who have new or worsening respiratory symptoms, and permanently discontinue treatment in patients with severe ILD and/or pneumonitis. Specific risk factors for severe lung inflammation among patients on these drugs have not been identified. The FDA has approved new warnings about this risk to the prescribing information and patient package insert for this entire class of these kinase inhibitors. The overall benefit of CDK 4/6 inhibitors is still greater than the risks when used as prescribed, the FDA says. CDK 4/6 inhibitors have been shown to improve patients' progression-free survival. Source
