Definition

A recombinant, human Fc-inert monoclonal antibody targeting lymphocyte-activation gene 3 protein (LAG-3; LAG3), with potential immune checkpoint inhibitory and antineoplastic activities. Upon intravenous administration, monoclonal antibody Sym022 binds to human LAG-3 and blocks the interaction between LAG-3 and major histocompatibility complex class II (MHCII) molecules on the surface of antigen-presenting cells (APCs) and tumor cells. This prevents the negative regulation of T-cell activity that occurs via LAG-3-MHCII binding and enhances a cytotoxic T-lymphocyte (CTL)-mediated immune response against tumor cells. Additionally, Sym022 decreases LAG-3 surface levels through internalization and shredding. LAG-3 plays a key role in the activation of T cells and natural killer (NK) cells.