AB-CD40L

AB-CD40L is a preclinical-stage oral small-molecule inhibitor developed by Arcus Biosciences, in collaboration with Gilead Sciences, targeting the CD40 ligand (CD40L, also known as CD154). CD40L is a critical costimulatory protein expressed on T cells that interacts with CD40 on B cells and other antigen-presenting cells, playing a central role in immune activation and the pathogenesis of autoimmune diseases. By inhibiting this pathway, AB-CD40L aims to provide a potent, orally bioavailable alternative to existing injectable therapies for inflammatory and autoimmune conditions, specifically multiple sclerosis and systemic lupus erythematosus. The program is part of Arcus's inflammation and immunology (I&I) portfolio, with the first clinical study planned for 2026.