Ofirnoflast: A First-in-Class NEK7-Targeted Inhibitor of the NLRP3 Inflammasome

Ofirnoflast is a first-in-class, orally bioavailable NEK7 inhibitor currently undergoing Phase 2 clinical evaluation. It disrupts NLRP3 inflammasome assembly by targeting NEK7's scaffolding function-blocking complex formation independently of NLRP3 activation status, upstream of both caspase activation, and inflammatory cytokine release. This unique mechanism offers a novel approach to treating chronic inflammatory diseases as demonstrated in a colitis model. Unlike NSAIDs, corticosteroids, cytokine-neutralizing biologics, and NLRP3-directed small molecules-which are frequently limited by off-target effects, immunosuppression, or incomplete efficacy-ofirnoflast provides a targeted approach with fewer anticipated liabilities.We demonstrate that ofirnoflast engages a conserved allosteric site adjacent to NEK7's ATP-binding pocket, inducing conformational shifts that impair its scaffolding function. In THP-1 macrophages and human iPSC-derived microglia, ofirnoflast dose-dependently suppresses ASC specks, IL-1β release, and pyroptotic cell death. Biophysical assays, including differential scanning fluorimetry and limited proteolysis, confirm that ofirnoflast stabilizes NEK7 in a unique conformation, which is supported by molecular dynamics simulations, indicative of a type-2 kinase-inhibitor binding mode.In vivo, ofirnoflast exhibits favorable oral bioavailability, achieving systemic exposures well above cellular potency thresholds. In a DSS-induced colitis model, treatment significantly reduces cytokine levels and improves clinical and histopathological outcomes. These data identify NEK7 as a novel, druggable target in NLRP3 inflammasome signaling and support ofirnoflast's potential as a differentiated therapeutic agent for certain chronic inflammatory diseases.