In hormone positive, human epidermal growth factor receptor 2 (HER2)-negative advanced and metastatic breast cancer, the cyclin-dependent kinase (CDK) 4/6 inhibitors palbociclib, ribociclib and abemaciclib, in combination with endocrine therapy have shown superior progression free and overall survival rates compared with endocrine therapy only. All three agents are approved for women with advanced and metastatic hormone positive, HER-2 negative breast cancer in the first- and second-line settings [1].
