rrx-001 and Inflammation

Chronic unresolving inflammation is emerging as a key underlying pathological feature of many if not most diseases ranging from autoimmune conditions to cardiometabolic and neurological disorders. Dysregulated immune and inflammasome activation is thought to be the central driver of unresolving inflammation, which in some ways provides a unified theory of disease pathology and progression. Inflammasomes are a group of large cytosolic protein complexes that, in response to infection- or stress-associated stimuli, oligomerize and assemble to generate a platform for driving inflammation. This occurs through proteolytic activation of caspase-1-mediated inflammatory responses, including cleavage and secretion of the proinflammatory cytokines interleukin (IL)-1β and IL-18, and initiation of pyroptosis, an inflammatory form of cell death. Several inflammasomes have been characterized. The most well-studied is the nucleotide-binding domain (NOD)-like receptor protein 3 (NLRP3) inflammasome, so named because the NLRP3 protein in the complex, which is primarily present in immune and inflammatory cells following activation by inflammatory stimuli, belongs to the family of nucleotide-binding and oligomerization domain (Nod) receptor proteins. Several NLRP3 inflammasome inhibitors are in development, all with multi-indication activity. This review discusses the current status, known mechanisms of action, and disease-modifying therapeutic potential of RRx-001, a direct NLRP3 inflammasome inhibitor under investigation in several late-stage anticancer clinical trials, including a phase 3 trial for the treatment of third-line and beyond small cell lung cancer (SCLC), an indication with no treatment, in which RRx-001 is combined with reintroduced chemotherapy from the first line, carboplatin/cisplatin and etoposide (ClinicalTrials.gov Identifier: NCT03699956). Studies from multiple independent groups have now confirmed that RRx-001 is safe and well tolerated in humans. Additionally, emerging evidence in preclinical animal models suggests that RRx-001 could be effective in a wide range of diseases where immune and inflammasome activation drives disease pathology.

Topics: Animals; Humans; Inflammasomes; Inflammation; NLR Family, Pyrin Domain-Containing 3 Protein; Nucleotides

RRx-001 is a small molecule NLRP3 inflammasome inhibitor with anti-CD47 and antiangiogenic/vascular normalization properties in a Phase 3 clinical trial that has been designated as a drug-device combination by the FDA. In the Phase 1 first-in-man dose escalation clinical trial, where RRx-001 was given by direct intravenous (IV) infusion, the main adverse event was a sterile painful infusion phlebitis (IP). Less pain was experienced when RRx-001 was infused at a slower rate over multiple hours which was impractical on an outpatient basis. In Phase 2, for reasons of convenience and safety, RRx-001 was co-administered with an aliquot of autologous blood from an

Topics: Animals; Azetidines; Hemoglobins; Inflammasomes; Inflammation; Nitro Compounds; NLR Family, Pyrin Domain-Containing 3 Protein; Phlebitis; Rats; Rats, Wistar

The NLRP3 inflammasome plays a crucial role in innate immune-mediated inflammation and contributes to the pathogenesis of multiple autoinflammatory, metabolic and neurodegenerative diseases, but medications targeting the NLRP3 inflammasome are not available for clinical use. RRx-001 is a well-tolerated anticancer agent currently being investigated in phase III clinical trials, but its effects on inflammatory diseases are not known. Here, we show that RRx-001 is a highly selective and potent NLRP3 inhibitor that has strong beneficial effects on NLRP3-driven inflammatory diseases. RRx-001 inhibits the activation of the canonical, noncanonical, and alternative NLRP3 inflammasomes but not the AIM2, NLRC4 or Pyrin inflammasomes. Mechanistically, RRx-001 covalently binds to cysteine 409 of NLRP3 via its bromoacetyl group and therefore blocks the NLRP3-NEK7 interaction, which is critical for the assembly and activation of the NLRP3 inflammasome. More importantly, RRx-001 treatment attenuates the symptoms of lipopolysaccharide (LPS)-induced systemic inflammation, dextran sulfate sodium (DSS)-induced colitis and experimental autoimmune encephalomyelitis (EAE) in mice. Thus, our study identifies RRx-001 as a new potential therapeutic agent for NLRP3-driven diseases.

Topics: Animals; Azetidines; CARD Signaling Adaptor Proteins; Colitis; Cysteine; Dextran Sulfate; Encephalomyelitis, Autoimmune, Experimental; Inflammasomes; Inflammation; Lipopolysaccharides; Macrophages; Mice, Inbred C57BL; NIMA-Related Kinases; Nitro Compounds; NLR Family, Pyrin Domain-Containing 3 Protein; Protein Domains