Anti-Claudin Therapeutic Programs in Oncology – 2026 Database Available

Claudins are a family of tight-junction proteins that seal the space between epithelial cells and govern what crosses the barrier. In healthy tissue, their extracellular loops sit buried inside intact junctions, largely inaccessible to antibodies. As tumors break down normal epithelial architecture, cancer disrupts the normal arrangement of cells and exposes claudins on the surface, leaving them vulnerable to therapeutic targeting — and several claudins are also re-expressed or mislocalized in cancer. The result is a therapeutic window that spares normal tissue.

That window is now clinically validated. CLDN18.2, normally restricted to gastric mucosa, became the first claudin target to reach approval: zolbetuximab (Vyloy) was approved by the FDA in October 2024 for HER2-negative, CLDN18.2-positive gastric and gastroesophageal junction adenocarcinoma, the first and only CLDN18.2-targeted therapy. CLDN6, an oncofetal antigen silent in most adult tissue, is being pursued in ovarian, testicular, and lung tumors, while CLDN1 and CLDN4 are drawing earlier-stage interest. Behind these targets sits a fast-growing pipeline of monoclonal antibodies, bispecifics, antibody-drug conjugates, and CAR T cells.