GSK2831781 is a monoclonal antibody being developed by GlaxoSmithKline (GSK) for autoimmune diseases. The antibody targets the T cell activation marker LAG-3, which is mainly expressed in inflamed tissues. In GSK's March 2015 Product development pipeline document the antibody is listed under 'Immuno-inflammation' candidates. GSK2831781 entered a Phase I clinical trial in psoriasis early in 2015.