Does an anticancer drug have to attack the cancer cell itself?
Pembrolizumab takes another approach. It binds PD-1 on immune cells and blocks interaction with PD-L1 and PD-L2, releasing an inhibitory signal that tumors can exploit to suppress T-cell activity.
Instead of poisoning the tumor directly, the drug changes the conversation between cancer and the immune system.
But PD-1 is a brake for a reason: blocking it can also let immune cells damage healthy tissues. Benefit and risk arise from the same act—releasing immune restraint.
Global Chemical Database