Potential Toxicities Associated With CDK4/6 Inhibitors in Breast Cancer
Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors such as palbociclib, ribociclib, and abemaciclib are changing the treatment paradigm for women with metastatic hormone receptor–positive breast cancer. According to a comprehensive review of potential toxicities and drug interactions associated with this class of drugs by Laura M. Spring, MD, and colleagues published in The Oncologist, CDK4/6 inhibitors generally are well-tolerated oral agents. The authors offer practical management strategies for oncologists on the safe use of CDK4/6 inhibitors.
“Given the excitement with these drugs, there has been considerable uptake in clinical practice for management of patients with metastatic breast cancer,” shared Aditya Bardia, MD, MPH, of the Massachusetts General Hospital Cancer Center in Boston, the senior author of this article, in a recent press release. “However, these agents are different from endocrine therapies and have a unique set of side effects.”
Based on their review of all the publicly available studies on these three CDK4/6 inhibitors, the most common adverse events linked to palbociclib and ribociclib are hematologic, particularly neutropenia. However, unlike chemotherapy-induced neutropenia, the impact of these newer agents on white blood cells appears to be temporary and dose-dependent. As for abemaciclib, fatigue and gastrointestinal side effects are more common, with cytopenias being less prevalent with this agent.