Palbociclib and Pembrolizumab In Central Nervous System Metastases

Administered orally once per day on days 1-21 of 28-day cycles.

Pembrolizumab is administered via intravenous (IV) infusion at a dose of 200 mg over 30 minutes once every 21 days. Pembrolizumab cycles are 3 weeks (21 days) long in this study, and participants in Cohort 2 can receive pembrolizumab as long as they are receiving study drug palbociclib.