Definition

A humanized immunoglobulin G1 (IgG1) monoclonal antibody directed against the inhibitory T-cell receptor T-cell immunoglobulin and mucin domain-containing protein 3 (TIM-3; TIM3; hepatitis A virus cellular receptor 2; HAVCR2), with potential immune checkpoint inhibitory and antineoplastic activities. Upon administration, surzebiclimab binds to TIM-3 expressed on certain T cells, including tumor-infiltrating lymphocytes (TILs), thereby preventing the engagement of TIM-3 by its ligands, phosphatidylserine (PtdSer) and galectin-9. This abrogates T-cell inhibition, activates antigen-specific T lymphocytes and enhances cytotoxic T-cell-mediated tumor cell lysis, which results in a reduction in tumor cell proliferation. TIM-3, a transmembrane protein and immune checkpoint receptor, is associated with tumor-mediated immune suppression.