Abstract
PD-L1 and PD-1 inhibitors were both developed to combat a huge array of cancers. Both classes of agents block the PD-1/PD-L1 pathway. Unlike PD-1 inhibitors, PD-L1 inhibitors do also block the B-7.1-receptor and leave the PD-L2/PD-1 axis unaffected. Whether these differences enhance efficacy and tolerability is not clear yet. There are three PD-L1 inhibitors approved or in late clinical development: Atezolizumab, approved in 2(nd)-line treatment of non-small cell lung cancer, durvalumab, showing promising results as a consolidation therapy in stage III disease and avelumab, the only drug exploiting antigen-dependent cytotoxicity. Future directions are the combination of these compounds with chemotherapy or other immuno-oncologic drugs.