The Pharmacological Profile of Cyclin-dependent Kinase (CDK) 4/6 Inhibitors: Clinical Management of Toxicity and Drug Interactions Related to CDK 4/6 Inhibitor-based Treatment in Advanced/Metastatic Breast Cancer

The emergence of cyclin-dependent kinase (CDK) 4 and 6 inhibitors has brought a new approach in the treatment of advanced hormone receptor (HR) positive breast cancer and human epidermal growth factor (HER) 2 negative breast cancer. To date, three CDK 4/6 inhibitors, palbociclib, ribociclib, and abemaciclib, are approved by the Food and Drug Administration (FDA); the first two agents are approved by the European Medicines Agency (EMA) as well. The family of CDKs consists of key regulatory enzymes that play a significant role in cell cycle progression. The aim of this review is to give an overview of the mechanism of action and the efficacy of CDK4/6 inhibitors and to highlight the most serious adverse events and the drug interactions related to these agents.