PD-L1 inhibitors in the pipeline: Promise and progress.

Checkpoint inhibitors have improved survival for patients with melanoma, non-small-cell lung cancer (NSCLC), bladder, head and neck and other cancers. Antibodies against PD-L1, including atezolizumab, avelumab and durvalumab, are also being developed and have been approved for various cancers. Compared with anti-CTLA-4 drugs, studies with anti-PD-1/PD-L1 agents have suggested higher response rates and improved survival. Targeting PD-L1 rather than PD-1 may also theoretically offer further benefit, with the potential for improved efficacy and reduced toxicity, although this has not been clearly shown by clinical experience to date. Anti-PD-L1 agents have shown good efficacy and manageable toxicity in several tumor types.