Atezolizumab Biosimilar, Human PD-L1 mAb

Atezolizumab is a humanized IgG1-kappa monoclonal antibody specific for human PD-L1, also known as B7-H1 or CD274. PD-L1 is a ligand for PD-1, a checkpoint protein expressed on activated T cells. PD-L1 binding to PD-1 causes the T cell to suppress its functions, a necessary event after the infectious agent has been eradicated or to prevent unwanted immune responses, e.g. during pregnancy. A number of cancers express PD-L1, suppressing anti-tumor T cell responses, and overexpression of PD-L1 is correlated with increased tumor aggressiveness and poorer prognosis. Atezolizumab binds directly and selectively to PD-L1, preventing it from binding to PD-1 and thereby relieving the suppression on the anti-tumor T cells. This Atezolizumab biosimilar has the same amino acid sequence as Atezolizumab, including the N297A mutation in the Fc domain that reduces binding to Fc receptors.