B7-H4

Class

B7-H4-directed antibody-drug conjugate (anti-B7-H4 IgG1, MMAE payload, DAR4, glucuronidase-cleavable linker)

Pathway

targets B7-H4, an immune-evasion checkpoint ligand overexpressed on solid tumors

B7-H4 (also called VTCN1) is a protein belonging to the B7 family of immune checkpoint ligands. Normally, B7 family members help regulate T-cell activity by delivering inhibitory signals that prevent excessive immune responses. Many solid tumors, including certain breast, ovarian, and endometrial cancers, express B7-H4 at high levels on their cell surface while healthy tissues express little of it. This pattern makes B7-H4 useful less as a target for direct immune checkpoint blockade and more as a homing beacon for targeted drug delivery. An antibody-drug conjugate (ADC) exploits this selectivity: an antibody that recognizes B7-H4 is chemically linked to a potent cytotoxic payload, in this case MMAE, a microtubule-disrupting agent. The antibody binds tumor cells displaying B7-H4, is taken inside the cell, and releases its payload after the linker is cleaved, killing the cancer cell from within while sparing tissues that lack the target. This strategy broadly matters in solid tumor oncology, where achieving tumor selectivity is a persistent challenge, and B7-H4's restricted normal-tissue expression combined with tumor overexpression offers a route to concentrate cytotoxic activity where it is needed most.