MUC16 x CD3

Class

MUC16xCD3 bispecific T-cell engaging antibody (Regeneron REGN4018). NOTE: input modality field 'small molecule' is incorrect — this is a bispecific antibody.

Pathway

T-cell engagement/redirection against MUC16-expressing tumor cells

MUC16 (also known as CA-125) is a large mucin protein expressed on the surface of certain epithelial cancers, most notably ovarian carcinoma, where it is markedly overexpressed compared with normal tissue. CD3 is a signaling component of the T-cell receptor complex present on essentially all mature T lymphocytes. A MUC16 x CD3 bispecific antibody is engineered with two different binding arms: one recognizes MUC16 on tumor cells, and the other recognizes CD3 on T cells. By binding both simultaneously, the molecule physically bridges a T cell to a tumor cell, forming an artificial immune synapse that triggers the T cell to become activated and kill the attached tumor cell, regardless of the T cell's normal antigen specificity. This approach, known as T-cell engagement or redirection, exploits the potent killing capacity of cytotoxic T cells without requiring pre-existing tumor-specific immunity. It is a strategy relevant to solid tumors that often evade endogenous immune surveillance, and MUC16-directed engagers are studied primarily in ovarian cancer and other malignancies where this mucin is highly expressed on the cell surface.