Question: is atezolizumab a checkpoint inhibitor?
Answer: One drug called ipilimumab (Yervoy®) blocks a checkpoint protein called CTLA-4. Two additional drugs, pembrolizumab (Keytruda®) and nivolumab (Opdivo®), target another checkpoint protein called PD-1. A third drug, atezolizumab (Tecentriq®), targets one called PD-L1.