Clinical Management of Potential Toxicities and Drug Interactions Related to Cyclin-Dependent Kinase 4/6 Inhibitors in Breast Cancer: Practical Considerations and Recommendations

The emergence of modern cyclin-dependent kinase (CDK) inhibitors has changed the treatment paradigm for metastatic hormone receptor (HR)-positive breast cancer. Palbociclib, ribociclib, and abemaciclib are highly selective reversible inhibitors of CDK4 and CDK6. Palbociclib is U.S. Food and Drug Administration (FDA)-approved in the first- and second-line settings in combination with endocrine therapy for HR-positive metastatic breast cancer. Ribociclib is FDA-approved in the first-line setting. Abemaciclib has received FDA Breakthrough Therapy designation status. This review focuses on the clinical management of potential toxicities and drug interactions seen with the use of CDK4/6 inhibitors in breast cancer.