Is there any data to support the combination of a CDK 4/6 inhibitor with tamoxifen?   

The best data for this combination comes from MONALEESA-7, which combined tamoxifen or an AI (+ ovarian suppression in all patients) with ribociclib or placebo in premenopausal women with advanced HR+, HER2 negative breast cancer.  This was presented at SABCS 2017.  Tamoxifen treatment was...