Inappropriate activation of the NLRP3 inflammasome has been implicated in multiple inflammatory and autoimmune diseases. Herein, we aimed to develop novel NLRP3 inhibitors that could minimize the risk of drug-induced liver injury. Lipophilic ligand efficiency was used as a guiding metric to identify a series of 6,7-dihydro-5H-pyrazolo­[5,1-b]­[1,3]­oxazinesulfonylureas. A leading compound from this series was advanced into safety studies in cynomolgus monkeys, and renal toxicity, due to compound precipitation, was observed. To overcome this obstacle, we focused on improving the solubility of our compounds, specifically by introducing basic amine substituents into the scaffold. This led to the identification of GDC-2394, a potent and selective NLRP3 inhibitor, with an in vitro and in vivo safety profile suitable for advancement into human clinical trials.

The NLRP3 inflammasome is an intracellular, multiprotein complex that promotes the auto-catalytic activation of caspase-1 and the subsequent maturation and secretion of the pro-inflammatory cytokines, IL-1β and IL-18. Persistent activation of the NLRP3 inflammasome has been implicated in the pathophysiology of a number of inflammatory and autoimmune diseases, including neuroinflammation, cardiovascular disease, non-alcoholic steatohepatitis, lupus nephritis and severe asthma. Here we describe the preclinical profile of JT002, a novel small molecule inhibitor of the NLRP3 inflammasome. JT002 potently reduced NLRP3-dependent proinflammatory cytokine production across a number of cellular assays and prevented pyroptosis, an inflammatory form of cell death triggered by active caspase-1. JT002 demonstrated in vivo target engagement at therapeutically relevant concentrations when orally dosed in mice and prevented body weight loss and improved inflammatory and fibrotic endpoints in a model of Muckle-Wells syndrome (MWS). In two distinct models of neutrophilic airway inflammation, JT002 treatment significantly reduced airway hyperresponsiveness and airway neutrophilia. These results provide a rationale for the therapeutic targeting of the NLRP3 inflammasome in severe asthma and point to the use of JT002 in a variety of inflammatory disorders.