TY - JOUR T1 - A Pan-Cyclophilin Inhibitor, CRV431, Decreases Fibrosis and Tumor Development in Chronic Liver Disease Models JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther DO - 10.1124/jpet.119.261099 SP - jpet.119.261099 AU - Joseph Kuo AU - Michael Bobardt AU - Udayan Chatterji AU - Patrick R Mayo AU - Daniel J Trepanier AU - Robert T Foster AU - Philippe Gallay AU - Daren R Ure Y1 - 2019/01/01 UR - http://jpet.aspetjournals.org/content/early/2019/08/12/jpet.119.261099.abstract N2 - Previous studies show that cyclophilins contribute to many pathological processes, and cyclophilin inhibitors demonstrate therapeutic activities in many experimental models. However, no drug with cyclophilin inhibition as the primary mode of action has advanced completely through clinical development to market. Here we present findings on the cyclophilin inhibitor, CRV431, that highlight its potential as a drug candidate for chronic liver diseases. CRV431 was found to potently inhibit all cyclophilin isoforms tested - A, B, D, and G. Inhibitory constant or IC50 values ranged from 1-7 nM which was up to 13 times more potent than the parent compound, cyclosporine A (CsA), from which CRV431 was derived. Other CRV431 advantages over CsA as a non-transplant drug candidate were significantly diminished immunosuppressive activity, less drug transporter inhibition, and reduced cytotoxicity potential. Oral dosing to mice and rats led to good blood exposures and a 5-15-fold accumulation of CRV431 in liver compared to blood concentrations across a wide range of CRV431 dosing levels. Most importantly, CRV431 decreased liver fibrosis in a 6-week carbon tetrachloride model and in a mouse model of non-alcoholic steatohepatitis (NASH). Additionally, CRV431 administration during a late, oncogenic stage of the NASH disease model resulted in a 50% reduction in the number and size of liver tumors. These findings are consistent with CRV431 targeting fibrosis and cancer through multiple, cyclophilin-mediated mechanisms and support the development of CRV431 as a safe and effective drug candidate for liver diseases.SIGNIFICANCE STATEMENT Cyclophilin inhibitors have demonstrated therapeutic activities in many disease models, but no drug candidates have yet advanced completely through development to market. Here CRV431 is shown to potently inhibit multiple cyclophilin isoforms, possess several optimized pharmacological properties, and decrease liver fibrosis and tumors in mouse models of chronic liver disease, which highlights its potential to be the first approved drug primarily targeting cyclophilin isomerases. ER -