Principal Investigators for Small Business: DiscoveryBioMed, Inc. (DBM) and Nitor Therapeutics, Inc. (Nitor) Project Summary Abstract The over-arching commercial goal for this Nitor Therapeutics, Inc. (Nitor) and DiscoveryBioMed, Inc. (DBM) collaboration is to discover and validate Stimulator of Interferon Genes or ?STING? inhibitor ligands in a novel high-throughput screening (HTS) and validation-based Critical Path of bioassays. Aberrant activation of the STING pathway by self DNA and ?gain of function? mutations in the STING protein dimer can lead to autoimmune disease. Therefore, we hypothesize that STING inhibitory ligands may be a promising new strategy for the treatment of autoimmune and inflammatory diseases in which suppression of the type I IFN pathway may show therapeutic benefit. The Nitor and DBM collaboration has designed a Critical Path of cell- based bioassays with HTS and validation bioassay steps so as to discover STING inhibitor ligands from a de novo screen of a diverse small molecule library derived from 8 different commercial vendors and from a targeted screen of nucleosides/nucleotides from our collaborators at TheraChem. Preliminary data is presented from a pilot screen of approximately 2,000 compounds and from early validation steps scripted within our Critical Path. Milestone 1 focuses on optimizing and cementing our STING Inhibitor HTS and Validation Critical Path. Later efforts in Milestone 1 will validate these STING inhibitors on additional reporter cell lines with more physiological relevance (a THP-1 monocytic cell line stably expressing the STING reporter) and on more relevant diseased human PBMCs isolated from lupus patients. Our validated STING inhibitor ligands will be evaluated by assessing the effect of the inhibitor ligand on the production and secretion of interferon-? (IFN-?) and other secreted inflammatory mediators in response to cGAMP. Milestone 2 will focus on the full HTS campaign to discover and validate novel small molecule STING inhibitors. Chemoinformatics analysis of the validated hits will be performed throughout the HTS campaign so as to identify emerging hit chemical series rapidly. We will then re-profile ?best in class? small molecules from each chemical series of family where a common scaffold has been identified. Phase 2 SBIR-driven work is envisioned where STING inhibitor ligand chemical series where medicinal and formulation chemistry optimization is performed on the best hit-to-lead chemical series, where in vitro ADME and in vivo PK/PD are performed, and where in vivo proof-of-concept studies are performed in lupus animal models and mouse models of interferonapathies with key lead small molecules. PHS 398/2590 (Rev. 09/04, re-issued 4/2006) Page Continuation Format Page
Principal Investigators for Small Business: DiscoveryBioMed, Inc. (DBM) and Nitor Therapeutics, Inc. (Nitor) Public Health Relevance Statement Autoimmune diseases are syndromes or disorders in which the body inappropriately targets its own organs, tissues or cells as being foreign or ?non-self.? DiscoveryBioMed, Inc. (DBM) and Nitor Therapeutics (Nitor) are focused on discovering novel ?Stimulator of Interferon Genes? or ?STING? inhibitors for autoimmune diseases. Among these autoimmune or ?autoinflammatory? diseases, it has become apparent that a recently discovered modulatory protein in immunity signaling called ?Stimulator of Interferon Genes? or ?STING? is affected directly or indirectly. The most common autoimmune disease is ?Lupus? (known formally as systemic lupus erythematosus or SLE). There is no cure for SLE, and it is mainly treated with medicines that suppress the immune system with the aim of keeping symptoms under control. These medicines have many debilitating side effects. As such, the ultimate goal and unmet clinical need is to discover and develop a more focused therapeutic for the ?Lupus umbrella of diseases.? Lupus falls under the mandate of the NIAID at the NIH and is a focus of Nitor Therapeutics. In addition, we are focused on more specific rare or niche autoimmune diseases within the Lupus umbrella. DBM is interested particularly in Respiratory and Renal Diseases therapeutic areas. Importantly, gain-of-function mutations in the STING gene cause early-onset lung vasculopathy and pulmonary inflammation in human patients, now categorized as ?SAVI? or ?STING-associated vasculopathy with onset in infancy.? These newly categorized diseases are hyperinflammatory in nature and affect mainly the lung, blood vessels within the lung and the skin. Patients with SAVI can also develop widespread lung damage that leads to pulmonary fibrosis and difficulty in breathing. The SAVI diseases fall under the NHLBI mission. Gain-of- function mutations in the gene encoding STING render the protein constitutively active or more sensitive to stimulation by cGAMP, which results in elevated production of interferons by a variety of cells. There are also other rare autoimmune disorders and syndromes that display a prominent interferon-response-gene signature that may be treated with a STING inhibitor. Of importance to DBM, STING inhibitors may also be beneficial in the treatment of lupus nephritis (LN). LN falls under the mission of the NIDDK. As such, Nitor Therapeutics, Inc. and DiscoveryBioMed, Inc. have formed a synergistic collaboration so as to discover novel and innovative STING inhibitor ligands from a high-throughput screening program using intact, living reporter cell lines. We will validate these inhibitors on primary leukocytes (PBMCs) isolated from Lupus patients monitoring for potential therapeutic effects in vitro. The ultimate commercial goal is to develop orally bioavailable and/or inhaled small molecule STING inhibitors for common and rare autoimmune diseases. PHS 398/2590 (Rev. 09/04, re-issued 4/2006) Page Continuation Format Page
