H-151 is an irreversible antagonist of the stimulator of interferon genes (STING) protein, a central signalling component of the cytosolic DNA sensing pathway. Although STING is a vital component of the innate immune pathways, it has also been shown to have a pathogenic role in some inflammatory diseases. H-151 is a potent and selective STING antagonist with inhibitory activity both in human cells and in vivo in mice. Given as a pretreatment, H-151 was shown to attenuate pathological features of autoinflammatory disease in mouse models, reducing systemic cytokine responses in mice treated with the STING agonist 10-carboxymethyl-9-acridanone (CMA)