Is there a role for any of the CDK4/6 inhibitors in ER+/HER2+ or ER-/HER2+ metastatic breast cancer?  

This question is being addressed in clinical trials of CDK4/6 inhibitors. In preclinical studies, CDK4/6 inhibition induces senescence in HER2 positive breast cancer cell lines and there is synergistic anti-tumor activity with combined HER2 targeted agents and CDK4/6 inhibitors. As a downstream targ...