T-cell–engaging bispecific antibodies are designed to bind to T cells and tumor-associated antigens, leading to T-cell activation and tumor cell death.1 These molecules directly engage T cells without requiring an antigen-specific immune response and may be able to counter the immune evasion capabilities of tumor cells.2 These antibodies rely upon unedited endogenous T cells rather than engineered T cells.3
Genentech is developing T-cell–engaging antibody structures that leverage both monovalent and bivalent binding.
- Antibodies with monovalent binding have 1 Fab arm that binds to CD3 on T cells, while the other Fab arm binds to a tumor cell surface
antigen4-6 - Antibodies with bivalent binding have a 2:1 structure: 1 Fab arm binds to CD3, while 2 Fab arms bind to tumor antigens. Bivalent binding is designed for high-avidity binding to tumor antigens1,2