Abstract 17824: Gemcabene and Atorvastatin Alone and Combined Markedly Reduce LDL-C in LDL Receptor-deficient Mice, a Model of Homozygous Familial Hypercholesterolemia
Background: Gemcabene (Gem) is a late-stage Phase 2 clinical candidate being evaluated for the reduction of low-density lipoprotein cholesterol (LDL-C) in homozygous familial hypercholesterolemia (HoFH) patients. Combination therapy includes statins as standard of care to treat this genetic disorder. LDL-deficient (LDLr) mice have been widely used with lipid-lowering agents to demonstrate LDL-C lowering with good translation to clinical efficacy. We have previously shown that atorvastatin (Atorva) reduces LDL-C and apoB in the LDLr deficient mice and in casein-fed (endogenous hypercholesterolemic) rabbits.
Experiment and Results: In the current study, we assessed Gem and Atorva effects alone and in combination on reduction of LDL-C in chow-fed LDLr deficient mice, an animal model of HoFH. Baseline LDL-C and total cholesterol were 246±20 mg/dL and 329±23 mg/dL in these mice Female LDLr deficient mice (n=10) were treated with Atorva alone (60mg/kg/day), Gem alone (60/mg/kg/day) or the agents combined (Atorva + Gem)(each at 60 mg/kg/day) for 14 days. Following treatments with Atorva, Gem, and Atorva+Gem, fasting LDL-C reduced by 22%, 55% and 72%, respectively, and total cholesterol by 21%, 47%, and 58%, respectively; showing additional reduction of 50% LDL-C by Gem on top of Atorva alone. Since LDLr are absent in these mice, similar to HoFH patients, the LDL-C lowering by Gem could be due to reduced VLDL production rates. Indeed, our studies in rat hepatocytes and in apoB100-only mice (apobec-1 knockout) showed reduced radioactivity in cholesterol and triglyceride fractions in the hepatocytes and in the plasma and liver of mice administered 14C acetate, suggesting cholesterol and fatty acid synthesis inhibition as a mechanism of LDL-C lowering. Gem also enhances the clearance of VLDL in normal rats. We propose both mechanisms may contribute to LDL-C reduction in LDLr deficient mice. A more detailed kinetic study of Gem in LDLr deficient models is underway to verify these proposed mechanisms.
Conclusions: Gemcabene alone and combined with atorvastatin significantly (55-72%) reduced LDL-C in this predictive in-vivo HoFH disease model. These findings suggest that treatment with Gem on top of standard of care therapy by statins may benefit HoFH patients.
Author Disclosures: C.L. Bisgaier: Employment; Significant; Gemphire Therapeutics Inc. Ownership Interest; Significant; Gemphire Therapeutics Inc. B.J. Auerbach: Ownership Interest; Significant; Gemphire Therapeutics Inc. Consultant/Advisory Board; Significant; Gemphire Therapeutics Inc.
- © 2015 by American Heart Association, Inc.