Cycling Toward Progress: Ribociclib, a CDK 4/6 Inhibitor for Breast Cancer.

Ribociclib is an orally active, highly selective inhibitor of cyclin-dependent kinase (CDK) 4 and 6. It is the second CDK 4/6 inhibitor approved for hormone receptor-positive breast cancer. The addition of ribociclib to an aromatase inhibitor has resulted in marked improvements in progression-free survival for patients with metastatic breast cancer. Clin Cancer Res; 24(13); 2981-3. ©2018 AACRSee related article by Shah et al., p. 2999. ©2018 American Association for Cancer Research.