Claudin‐targeted drug development using anti‐claudin monoclonal antibodies to treat hepatitis and cancer

The 27‐member family of tetraspan membrane proteins known as claudins (CLDNs) is a major component of tight junctions. A series of studies elucidating the relationship between CLDNs and various pathological conditions has provided new insights into drug development. For instance, CLDN‐1 may be a potent target for epidermal absorption of drugs and for treating hepatitis C virus (HCV) infection. CLDN‐4 may be a target for treating cancer. Because CLDNs are also expressed in various normal tissues, safety and efficacy evaluations are critical for translational research. We previously developed several anti‐CLDN antibodies and have established proof of concept for CLDN‐targeted drug development using these reagents. Here, we provide an overview of CLDN‐1 as a target for improving epidermal drug absorption and preventing HCV infection and of CLDN‐4 as a target for anticancer therapeutics.