SBIR-STTR Award

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) result from a common pathogenic process: pulmonary injury or infection triggers an overwhelming inflammatory response ("cytokine storm") that results in increased endothelial and epithelial permeability and efflux of inflammatory cells, protein, and water from the vascular system into the alveolar space. The incidence of ALI is estimated to be approximately 79 cases per 100,000 person-years. The treatment for those afflicted remains largely supportive with a mortality rate of approximately 40%. We have demonstrated that the small GTPase, Arf6, is a convergence point in the signaling pathways of several inflammatory mediators and cytokines with demonstrated involvement in ALI/ARDS. Activation of Arf6 into its GTP-bound state induces vascular leak and edema, which play major roles in the pathophysiology of ALI/ARDS. Thus, we hypothesize that pharmacological inhibition of Arf6 provides an opportunity to combat actions of multiple cytokines in ALI/ARDS, an approach which may be more effective than targeting single pathways with highly specific inhibitors. This rationale is supported by the encouraging preliminary in vivo data generated with our small molecule inhibitor of Arf6, NAV-2729, in a murine model of lipopolysaccharide (LPS)- induced ALI. This phase 1 SBIR will improve upon our current NAV-2729 series of Arf6 inhibitors through an in silico molecular modeling effort to identify compounds with improved potency and hydrophilicity. We will determine potency in a biochemical nucleotide exchange assay and verify activity in a mechanism-based cellular Arf6 pulldown assay. Compounds with an optimal mix of potency and hydrophilicity will be screened in vivo to determine pharmacokinetic (PK) parameters. We will then demonstrate proof-of-concept efficacy in the murine LPS-induced ALI model. Successful completion of these activities will accomplish two very important goals. First, it will provide proof- of-concept that inhibiting Arf6 is a promising novel approach for treating ALI/ARDS. Second, it will position us to continue medicinal chemistry optimization of Arf6 inhibitors in Lead Optimization activities in phase 2 (optimization of potency, selectivity, solubility, ADMET properties, patentability). Successful completion of this development program may result in a therapy effective for treating humans with ALI/ARDS.

Public Health Relevance Statement:


Public Health Relevance:
Acute lung injury (ALI) and the more severe acute respiratory distress syndrome (ARDS) result from a common pathogenic process: pulmonary injury or infection triggers an overwhelming inflammatory response ("cytokine storm") that results in increased endothelial and epithelial permeability and efflux of inflammatory cells, protein, and water from the vascular system into the alveolar space. The incidence of ALI is estimated to be approximately 79 cases per 100,000 person-years. Treatment for ALI/ARDS is primarily supportive care and though there have been improvements in outcomes over the past decade due to improved strategies of mechanical ventilation and advances in general supportive measures, the mortality rate of patients with ALI/ARDS is approximately 40%.

Project Terms:
Acute; Adult Respiratory Distress Syndrome; Albumins; Alveolar; Animal Model; Bacterial Pneumonia; base; Biochemical; Biological Assay; Biological Availability; Biological Warfare; Blood; Blood Transfusion; Blood Vessels; Breathing; Bronchoalveolar Lavage Fluid; Burn injury; Cause of Death; Cell Count; Cells; Cellular Assay; Chemical Warfare; Chemicals; combat; compound 30; Computer Simulation; cytokine; Cytokine Signaling; Data; design; Development; Dose; Drug Kinetics; Dyes; Edema; effective therapy; Epithelial; Etiology; Evaluation; Evans blue stain; Extravasation; Functional disorder; Goals; GTP Binding; Half-Life; Human; hydrophilicity; improved; in vivo; Incidence; Infection; Inflammation Mediators; Inflammatory; Inflammatory Response Pathway; inhibitor/antagonist; Injury; Interleukin-6; intraperitoneal; Intravenous; Lead; Lipopolysaccharides; Lung; lung injury; Lung Injury, Acute; Measures; Mechanical ventilation; Modeling; Modification; molecular modeling; Molecular Models; Monomeric GTP-Binding Proteins; Mortality Vital Statistics; mouse model; Mus; neutrophil; novel strategies; Nucleotides; Organ failure; Outcome; Pathway interactions; Patients; Permeability; Persons; Pharmaceutical Chemistry; Pharmacology; pharmacophore; Phase; Play; Positioning Attribute; Preclinical Drug Development; Process; Program Development; Property; Proteins; public health relevance; Relative (related person); Role; Safety; Sepsis; Sepsis Syndrome; Series; Signal Pathway; Small Business Innovation Research Grant; small molecule; Solubility; Structure of parenchyma of lung; Supportive care; Testing; Time; TNF gene; Toxicology; Trauma; Treatment Efficacy; Vascular System; Viral Pneumonia; Water; Weight

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) result from a common pathogenic process: pulmonary injury or infection triggers an overwhelming inflammatory response (“cytokine storm”) that results in increased endothelial and epithelial permeability and efflux of inflammatory cells, protein, and water from the vascular system into the alveolar space. The further release of inflammatory agents from damaged lung tissue often triggers systemic inflammatory response syndrome (SIRS) and end organ failure, the main cause of death in ALI/ARDS. ALI and ARDS are precipitated by diverse etiologies including aspiration, inhalation injury, bacterial and viral pneumonias, trauma, burn injury, blood transfusion, sepsis, and other factors. In fact, biologic and chemical warfare agents are often selected for their ability to cause the devastating effects of ALI/ARDS. The incidence of ALI is estimated to be approximately 79 cases per 100,000 person-years. Improvements in outcome have come about over the past decade due to improved strategies of mechanical ventilation and advances in general supportive measures. Unfortunately, even today, the treatment for those afflicted remains largely supportive with a mortality rate of approximately 40%. Navigen’s objective is to develop a small molecule ARF6 inhibitor as a treatment for ALI/ARDS. In Phase I, we presented ARF6 as a target for treatment of ALI/ARDS, and we shared data establishing the potential therapeutic value of inhibiting ARF6 to treat ALI/ARDS. The specific aims of our Phase I application were to identify a number of ARF6 inhibitors with required potency and solubility, to characterize the pharmacokinetic (PK) properties of a small number of these compounds, and to obtain convincing in vivo proof-of-concept efficacy in a mouse model of LPS-induced ALI, exploring both dose-response relationships and time-of-treatment effects. We accomplished these goals and identified five compounds of interest. Since submitting our Phase II application in January, 2016, we have made significant progress and have identified a lead candidate, NAV-5093, to carry forward into Phase II. NAV-5093 is a water-soluble lysine prodrug (dihydrochloride salt) of NAV-4424, itself one of the leading 5 candidates identified in Phase I. NAV-5093 has the advantage of high water solubility, making it amenable to formulation for intravenous (IV) administration in the hospital setting for treatment of ALI/ARDS. NAV-5093 is cleaved rapidly to release parent NAV-4424 in vivo, and is effective in the mouse model of LPS- induced ALI as well as in Acinetobacter baumannii (AB)-induced pneumonia in neutropenic mice. Over the next two years in Phase II, we propose to accomplish the following: (1) demonstrate efficacy of NAV-5093 in two rat models of ALI using accepted outcome measures, (2) characterize the in vitro ADME and in vivo PK properties of NAV-5093, (3) conduct initial toxicity studies of NAV-5093 in rats, (4) manufacture NAV-5093 and optimize an aqueous formulation of NAV-5093 for IV administration, and (5) hold a pre-IND meeting with the FDA.

Public Health Relevance Statement:
PROJECT NARRATIVE Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are life-threatening conditions precipitated by diverse etiologies including aspiration, inhalation injury, bacterial and viral pneumonias, trauma, burn injury, blood transfusion, sepsis, and other factors. Treatment for those afflicted remains largely supportive with a mortality rate of approximately 40%. We are advancing our lead small molecule inhibitor of ARF6, NAV-5093, as treatment for ALI/ARDS.

Project Terms:
Acinetobacter baumannii; Acute Lung Injury; ADME Study; Adult Respiratory Distress Syndrome; Alveolar; analytical method; animal efficacy; aqueous; Area Under Curve; Bacterial Pneumonia; Binding Proteins; Biological Assay; Biological Sciences; Biological Warfare; Blood Transfusion; Breathing; Burn injury; Canis familiaris; Cause of Death; Cells; Chemical Warfare Agents; Cleaved cell; Clinical; cytokine; Data; Development; Dose; Drug Kinetics; Epithelial; Esters; Etiology; experience; Feedback; Formulation; Funding; Goals; Hepatocyte; Hospitals; Hour; Human; improved; In Vitro; in vivo; Incidence; Infection; Inflammatory; Inflammatory Response; inhibitor/antagonist; Injury; interest; intraperitoneal; Intraperitoneal Injections; Intravenous; irritation; Lead; Life; Liver Microsomes; Lung; Lysine; Measures; Mechanical ventilation; meetings; metabolic profile; method development; Modeling; mortality; mouse model; Mus; Organ failure; Oryctolagus cuniculus; Outcome; Outcome Measure; Parents; Pathogenicity; Permeability; Persons; Pharmacology Study; Phase; Plasma; Plasma Proteins; Pneumonia; Polymorph; Process; Prodrugs; programs; Property; Proteins; Pseudomonas aeruginosa; Rattus; Research Design; response; Rodent; Running; Safety; safety study; screening; Sepsis; Sepsis Syndrome; sharing data; small molecule; small molecule inhibitor; Sodium Chloride; Solubility; Structure of parenchyma of lung; Testing; Therapeutic; Time; Toxic effect; Toxicology; Trauma; treatment effect; United States National Institutes of Health; Vascular System; Viral Pneumonia; Water; water solubility