What protein is the target of pembrolizumab's binding?

What does pembrolizumab bind to?

Pembrolizumab binds to the programmed death-1 (PD-1) protein on T cells, blocking the PD-1 pathway. This helps T cells remain active against cancer cells. [1]

Is the target PD-L1 or PD-1?

Pembrolizumab’s binding target is PD-1, not PD-L1. (Other immunotherapies may target PD-L1, but pembrolizumab specifically binds PD-1.) [1]

Where is this described in drug information?

Drug labeling and references describing pembrolizumab’s mechanism of action identify PD-1 as its binding target. [1]

Sources

[1] https://www.drugs.com/pembrolizumab.html