Profile of abemaciclib and its potential in the treatment of breast cancer.

Hormone-receptor-positive breast cancer is the most common subtype of breast cancer among patients with both early-stage and metastatic disease. Recent advances in the understanding of its pathophysiology have led to the discovery and utilization of targeted inhibitors to cyclin-dependent kinases 4 and 6 (CDK4/6). There are currently three available CDK4/6 inhibitors available for use in USA: palbociclib, ribociclib, and abemaciclib. Their oral administration and tolerable toxicities make this class of agents appealing to both patients and health care providers. Abemaciclib, the most recently approved CDK4/6 inhibitor, has unique pharmacologic properties and potential toxicities. This review highlights the current understanding of abemaciclib and discusses its current and future roles in the treatment of breast cancer.