RU.521

RU.521 is a potent and selective small molecule inhibitor of cyclic GMP–AMP synthase (cGAS), an enzyme that plays a central role in the innate immune response by sensing cytosolic double-stranded DNA and triggering type I interferon production[1][2][4]. By inhibiting cGAS activity, RU.521 suppresses cGAS-mediated interferon upregulation and downstream inflammatory signaling[3][6]. It is more potent against murine cGAS than human cGAS but shows activity in both species[4][7]. The compound has been used primarily as a research tool to study the role of the cGAS–STING pathway in autoimmune diseases such as Aicardi-Goutières syndrome and kidney fibrosis models[5]. Its development status remains preclinical with no current clinical trials or approvals for therapeutic use.

Other names

3-[1-(6,7-Dichloro-1H-benzimidazol-2-yl)-5-hydroxy-3-methylpyrazol-4-yl]-3H-isobenzofuran-1-one