Review of cyclin-dependent kinase 4/6 inhibitors in the treatment of advanced or metastatic breast cancer.

CDK 4/6 inhibitors have demonstrated safety and tolerability in HR-positive/HER2-negative breast cancer patients. Real world safety data and out-of-pocket patient costs in addition patient specific comorbidities should be considered when developing a treatment plan that includes a CDK 4/6 inhibitor selection.