A paradigm shift for the treatment of hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2-) advanced breast cancer: a review of CDK inhibitors.

In the last 3 years, a novel class of targeted therapy has been approved for patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2-) breast cancer. There are currently three approved agents, which are oral cyclin-dependent kinase 4/6 (CDK4/6) inhibitors. All of the approved drugs exhibit progression-free survival benefit when compared to standard of care and generally have less adverse events compared to traditional chemotherapeutic options.