Influence of Various Central Moieties on the Hypolipidemic Properties of Long Hydrocarbon Chain Diols and Diacids

Phase 1, Single- and Multiple-Ascending-Dose, Food-Effect, and East Asian Subject Studies to Assess the Pharmacokinetics, Safety, and Tolerability of Bempedoic Acid, a Selective Inhibitor of Adenosine Triphosphate Citrate Lyase

Bempedoic acid is an adenosine triphosphate citrate lyase inhibitor that lowers low-density lipoprotein cholesterol by inhibiting cholesterol synthesis and upregulating hepatic low-density lipoprotein receptor expression. After oral dosing, bempedoic acid was readily absorbed, attaining maximum concentrations with a median time of 3.5 hours, and may be taken without regard to food. Steady-state oral pharmacokinetics in healthy adults receiving bempedoic acid at the approved 180 mg/day dose were characterized by mean maximum concentration of 20.6 µg/mL, area under the concentration-time curve over 24 hours of 289 µg·h/mL, and elimination half-life of 21.1 hours. Multiple-dose pharmacokinetics were linear at bempedoic acid doses of 120-220 mg/day. Circulating concentrations of the active metabolite ESP15228 were 18.0% of bempedoic acid concentrations on average. Comparisons of bempedoic acid 180 mg/day pharmacokinetics after single and multiple dosing revealed no clinically meaningful differences between Japanese, Chinese, and Western subjects. Mean estimates of bempedoic acid elimination half-life in Japanese (25.2 hours) and Chinese (20.0 hours) subjects were comparable to Western subjects (23.9 hours) following 14 days of once-daily dosing. Bempedoic acid was generally safe and well tolerated up to a dose of 220 mg/day across the study populations described herein.

Discovery of analogues of non-β oxidizable long-chain dicarboxylic fatty acids as dual inhibitors of fatty acids and cholesterol synthesis: Efficacy of lead compound in hyperlipidemic hamsters reveals novel mechanism

BACKGROUND AND AIMS

Cholesterol and triglycerides are risk factors for developing cardiovascular disease. Therefore, appropriate cells and assays are required to discover and develop dual cholesterol and fatty acid inhibitors. A predictive hyperlipidemic animal model is needed to evaluate mechanism of action of lead molecule for therapeutic indications.

METHODS AND RESULTS

Primary hepatocytes from rat, hamster, rabbit, and humans were compared for suitability to screen compounds by de novo lipogenesis (DNL) using14C-acetate. Hyperlipidemic hamsters were used to evaluate efficacy and mode of action. In rat hepatocytes DNL assay, both the central moiety and carbon chain length influenced the potency of lipogenesis inhibition. In hyperlipidemic hamsters, ETC-1002 decreased plasma cholesterol and triglycerides by 41% and 49% at the 30 mg/kg dose. Concomitant decreases in non-esterified fatty acids (-34%) and increases in ketone bodies (20%) were associated with induction of hepatic CPT1-α. Reductions in proatherogenic VLDL-C and LDL-C (-71% and -64%) occurred partly through down-regulation of DGAT2 and up-regulation of LPL and PDK4. Activation of PLIN1 and PDK4 dampened adipogenesis and showed inverse correlation with adipose mass. Hepatic concentrations of cholesteryl ester and TG decreased by 67% and 64%, respectively. Body weight decreased with concomitant decreases in epididymal fat. Plasma and liver concentrations of ETC-1002 agreed with the observed dose-response efficacy.

CONCLUSIONS

Taken together, ETC-1002 reduced proatherogenic lipoproteins, hepatic lipids and adipose tissues in hyperlipidemic hamsters via induction of LPL, CPT1-α, PDK4, and PLIN1, and downregulation of DGAT2. These characteristics may be useful in the treatment of fatty livers that causes non-alcoholic steatohepatitis.

ATP-citrate lyase (ACLY) in lipid metabolism and atherosclerosis: An updated review

ATP citrate lyase (ACLY) is an important enzyme linking carbohydrate to lipid metabolism by generating acetyl-CoA from citrate for fatty acid and cholesterol biosynthesis. Mendelian randomization of large human cohorts has validated ACLY as a promising target for low-density-lipoprotein-cholesterol (LDL-C) lowering and cardiovascular protection. Among current ACLY inhibitors, Bempedoic acid (ETC-1002) is a first-in-class, prodrug-based direct competitive inhibitor of ACLY which regulates lipid metabolism by upregulating hepatic LDL receptor (LDLr) expression and activity. ACLY deficiency in hepatocytes protects from hepatic steatosis and dyslipidemia. In addition, pharmacological inhibition of ACLY by bempedoic acid, prevents dyslipidemia and attenuates atherosclerosis in hypercholesterolemic ApoE^-/- mice, LDLr^-/- mice, and LDLr^-/- miniature pigs. Convincing data from clinical trials have revealed that bempedoic acid significantly lowers LDL-C as monotherapy, combination therapy, and add-on with statin therapy in statin-intolerant patients. More recently, a phase 3 CLEAR Harmony clinical trial ("Safety and Efficacy of Bempedoic Acid to Reduce LDL Cholesterol") has shown that bempedoic acid reduces the level of LDL-C in hypercholesterolemic patients receiving guideline-recommended statin therapy with a good safety profile. Hereby, we provide a updated review of the expression, regulation, genetics, functions of ACLY in lipid metabolism and atherosclerosis, and highlight the therapeutic potential of ACLY inhibitors (such as bempedoic acid, SB-204990, and other naturally-occuring inhibitors) to treat atherosclerotic cardiovascular diseases. It must be pointed out that long-term large-scale clinical trials in high-risk patients, are warranted to validate whether ACLY represent a promising therapeutic target for pharmaceutic intervention of dyslipidemia and atherosclerosis; and assess the safety and efficacy profile of ACLY inhibitors in improving cardiovascular outcome of patients.

Bempedoic acid: effects on lipoprotein metabolism and atherosclerosis

PURPOSE OF REVIEW

Bempedoic acid has emerged as a potent inhibitor of ATP-citrate lyase (ACLY), a target for the reduction of LDL cholesterol (LDL-C). We review the impact of bempedoic acid treatment on lipoprotein metabolism and atherosclerosis in preclinical models and patients with hypercholesterolemia.

RECENT FINDINGS

The liver-specific activation of bempedoic acid inhibits ACLY, a key enzyme linking glucose catabolism to lipogenesis by catalyzing the formation of acetyl-CoA from mitochondrial-derived citrate for de novo synthesis of fatty acids and cholesterol. Adenosine monophosphate-activated protein kinase activation by bempedoic acid is not required for its lipid-regulating effects in vivo. Mendelian randomization of large human study cohorts has validated ACLY inhibition as a target for LDL-C lowering and atheroprotection. In rodents, bempedoic acid decreases plasma cholesterol and triglycerides, and prevents hepatic steatosis. In apolipoprotein E-deficient (Apoe) mice, LDL receptor-deficient (Ldlr) mice and LDLR-deficient miniature pigs, bempedoic acid reduces LDL-C and attenuates atherosclerosis. LDLR expression and activity are increased in primary human hepatocytes and in Apoe mouse liver treated with bempedoic acid suggesting a mechanism for LDL-C lowering, although additional pathways are likely involved. Phase 2 and 3 clinical trials revealed that bempedoic acid effectively lowers LDL-C as monotherapy, combined with ezetimibe, added to statin therapy and in statin-intolerant hypercholesterolemic patients. Treatment does not affect plasma concentrations of triglyceride or other lipoproteins.

SUMMARY

The LDL-C-lowering and attenuated atherosclerosis in animal models and reduced LDL-C in hypercholesterolemic patients has validated ACLY inhibition as a therapeutic strategy. Positive results from phase 3 long-term cardiovascular outcome trials in high-risk patients are required for bempedoic acid to be approved for prevention of atherosclerosis.

Bempedoic Acid Lowers Low-Density Lipoprotein Cholesterol and Attenuates Atherosclerosis in Low-Density Lipoprotein Receptor–Deficient ( LDLR +/− and LDLR −/− ) Yucatan Miniature Pigs

Objective—

Bempedoic acid (BemA; ETC-1002) is a novel drug that targets hepatic ATP-citrate lyase to reduce cholesterol biosynthesis. In phase 2 studies, BemA lowers elevated low-density lipoprotein cholesterol (LDL-C) in hypercholesterolemic patients. In the present study, we tested the ability of BemA to decrease plasma cholesterol and LDL-C and attenuate atherosclerosis in a large animal model of familial hypercholesterolemia.

Approach and Results—

Gene targeting has been used to generate Yucatan miniature pigs heterozygous ( LDLR +/− ) or homozygous ( LDLR −/− ) for LDL receptor deficiency (ExeGen). LDLR +/− and LDLR −/− pigs were fed a high-fat, cholesterol-containing diet (34% kcal fat; 0.2% cholesterol) and orally administered placebo or BemA for 160 days. In LDLR +/− pigs, compared with placebo, BemA decreased plasma cholesterol and LDL-C up to 40% and 61%, respectively. In LDLR −/− pigs, in which plasma cholesterol and LDL-C were 5-fold higher than in LDLR +/− pigs, BemA decreased plasma cholesterol and LDL-C up to 27% and 29%, respectively. Plasma levels of triglycerides and high-density lipoprotein cholesterol, fasting glucose and insulin, and liver lipids were unaffected by treatment in either genotype. In the aorta of LDLR +/− pigs, BemA robustly attenuated en face raised lesion area (−58%) and left anterior descending coronary artery cross-sectional lesion area (−40%). In LDLR −/− pigs, in which lesions were substantially more advanced, BemA decreased aortic lesion area (−47%) and left anterior descending coronary artery lesion area (−48%).

Conclusions—

In a large animal model of LDLR deficiency and atherosclerosis, long-term treatment with BemA reduces LDL-C and attenuates the development of aortic and coronary atherosclerosis in both LDLR +/− and LDLR −/− miniature pigs.

ATP-citrate lyase: genetics, molecular biology and therapeutic target for dyslipidemia

PURPOSE OF REVIEW

ATP-citrate lyase (ACLY) has re-emerged as a drug target for LDL cholesterol (LDL-C) lowering. We review ACLY as a therapeutic strategy, its genetics, its molecular and cellular biology, and also its inhibition.

RECENT FINDINGS

ACLY is a critical enzyme linking glucose catabolism to lipogenesis by providing acetyl-CoA from mitochondrial citrate for fatty acid and cholesterol biosynthesis. Human genetic variants have been associated with enhanced growth and survival of several cancers, and with attenuated plasma triglyceride responses to dietary fish oil. In mice, liver-specific Acly deficiency protects from hepatic steatosis and dyslipidemia, whereas adipose tissue-specific Acly deletion has no phenotype, supporting therapeutic inhibition of ACLY. A lipid-regulating compound, bempedoic acid, was discovered to potently inhibit ACLY, and in animal models, it prevents dyslipidemia and attenuates atherosclerosis. Phase 2 clinical trials revealed that bempedoic acid effectively lowers LDL-C as monotherapy, combined with ezetimibe, added to statin therapy and in statin-intolerant hypercholesterolemic patients.

SUMMARY

The efficacy of bempedoic acid as an LDL-C-lowering agent has validated ACLY inhibition as a therapeutic strategy. Positive results of phase 3 patient studies, together with long-term cardiovascular disease outcome trials, are required to establish ACLY as a major new target in cardiovascular medicine.

Effects of acute combined serotonin and dopamine depletion on cue-induced drinking intention/desire and cognitive function in patients with alcohol dependence

BACKGROUND

Alcohol cues can precipitate the desire to drink and cause relapse in recovering alcohol-dependent patients. Serotonin and dopamine may play a role in alcohol cue-induced craving. Acute combined tryptophan (Trp), tyrosine (Tyr), and phenylalanine (Phe) depletion (CMD) in the diet attenuates the synthesis of serotonin and dopamine in the human brain. However, no study of the effects of acute CMD has been previously conducted. Therefore, we investigated whether the attenuation of serotonin and dopamine synthesis changes cue-induced alcohol craving in recently abstinent alcoholics.

METHODS

In this double-blind, randomized, placebo-controlled, crossover design, 12 male patients who met the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, criteria for alcohol dependence were divided into two conditions: (1) monoamine depletion (i.e., consumption of a concentrated amino acid beverage that resulted in a rapid and significant decrease in plasma-free Tyr/Phe/Trp) and (2) balanced condition (i.e., consumption of a similar beverage that contained Tyr/Phe/Trp). The participants were scheduled for two experimental sessions, with an interval of ≥7 days. The cue-induced craving test session was conducted 6h after each amino acid beverage administration. Drinking urge, blood pressure, heart rate, working memory, and attention/psychomotor performance were assessed before and after administration.

RESULTS

Compared with the balanced condition, the monoamine depletion condition significantly increased drinking intention/desire and diastolic blood pressure. Cognitive performance was not different between the two conditions.

CONCLUSIONS

Acute combined serotonin and dopamine depletion may increase drinking intention/desire and diastolic blood pressure without influencing cognitive function.

Mild decarboxylative activation of malonic acid derivatives by 1,1'-carbonyldiimidazole

Malonic acid derivatives undergo unusually mild decarboxylation when treated with N,N'-carbonyldiimidazole (CDI) at room temperature to generate the carbonyl imidazole moiety in high yield, which can be reacted further with a variety of nucleophiles in an efficient one-pot process.