NECTIN4 defines a subtype-dependent tumor state coupling enfortumab vedotin targetability to antitumor immunity in bladder cancer

NECTIN4 is the target of enfortumab vedotin (EV), but its biological role in bladder cancer (BC) and its relationship to EV plus PD-1 blockade remain unclear. Integrating clinical multi-omics, spatial and single-cell immune profiling, and experimental models, we identify NECTIN4 as a subtype-dependent determinant of tumor state and antitumor immunity. In basal BC cells, NECTIN4 suppressed inflammatory and mesenchymal programs. Consistently, NECTIN4-high basal/squamous muscle-invasive BCs showed favorable survival, higher checkpoint inhibitor response rates, and a coordinated CD8+ T cell-inflamed microenvironment with no comparable associations in luminal papillary tumors. In orthotopic models, murine Nectin4 promoted CD8+ T cell-dependent tumor control, whereas human NECTIN4 conferred EV sensitivity. EV also attenuated NECTIN4-dependent TIGIT binding. Conversely, NECTIN4-low models were preferentially sensitive to HDAC inhibition. NECTIN4 therefore couples antibody-drug conjugate targetability to a subtype-specific tumor-immune state permissive for checkpoint blockade, whereas the NECTIN4-low state defines a distinct inflammatory-mesenchymal state with an alternative therapeutic vulnerability.