Development of a Small Molecule Inhibitor of Fortilin for Atherosclerosis Treatment and Prevention

Project Summary Project Title: Development of a Small Molecule Inhibitor of Fortilin for Atherosclerosis Treatment and Prevention. Atherosclerosis affects more than 18 million Americans and is a major cause of cardiovascular diseases and acute cardiovascular events, such as heart attack and stroke. Current interventions include changes to diet and exercise, smoking cessation, and treatment with statins, but many patients struggle to adhere to lifestyle interventions and can experience significant side effects while taking statins. Although lipid lowering drugs have benefited patients with atherosclerosis, the idea that lipid lowering halts the progression of atherosclerosis is not valid because factors other than hypercholesterolemia have been shown to promote atherosclerosis. Therefore, there is a clear need for novel therapeutics that can directly inhibit plaque formation through a mechanism other than lipid lowering. Fortiscience, Inc. is developing an alternative therapeutic approach that inhibits fortilin, a key protein involved in atherosclerotic plaque formation. Fortilin protects macrophages against apoptosis in atherosclerotic intima, allowing them to proliferate and produce inflammatory cytokines. Strikingly, global knockdown of fortilin protects hypercholesterolemic mice against atherosclerosis without lowering cholesterol. Three small molecular weight compounds identified in preliminary work at the University of Washington have been shown to have activity in relevant in vitro and in vivo models, and these compounds have been used as the basis for designing and synthesizing 52 additional compounds with higher binding affinity through a medicinal chemistry approach. In this Phase I STTR project, to be conducted in collaboration with the University of Washington and the University of Notre Dame, 10 prioritized compounds will be evaluated using cell-based fortilin degradation and foam cell formation assays to assess activity (measuring the EC50) and cell death assays to determine cytotoxicity (LC50). Based on an analysis of the structure–activity relationship for these compounds, computational virtual docking assays will be performed to design and produce 3-5 new compounds with improved fortilin binding affinity. The binding affinity, activity, toxicity, and stability of these compounds will then be measured, and the data will be used to select a lead compound with a single-nanomolar dissociation constant, a lower EC50 value than the previous best-performing compound, and low clearance in liver microsome assays (CLint below 15 mL min-1kg-1). Further, pharmacokinetic and toxicity profiles will be determined for the lead compound in a 15-day oral dose range finding study in C57BL/6 mice. Finally, the anti-atherosclerotic activity of the lead compound will be determined in the aortae of hypercholesterolemic mice following 12 weeks of oral administration, with the goal of achieving a 50% reduction in atherosclerosis. This work is designed to provide the necessary proof-of-concept data to support further pre-clinical studies in Phase II and a future first-in-human clinical trial to establish the safety of the drug.