AMP-activated protein kinase and ATP-citrate lyase are two distinct molecular targets for ETC-1002, a novel small molecule regulator of lipid and carbohydrate metabolism

Effects of Bempedoic Acid in Acute Myocardial Infarction in Rats: No Cardioprotection and No Hidden Cardiotoxicity

Lipid-lowering drugs have been shown to have cardioprotective effects but may have hidden cardiotoxic properties. Therefore, here we aimed to investigate if chronic treatment with the novel lipid-lowering drug bempedoic acid (BA) exerts hidden cardiotoxic and/or cardioprotective effects in a rat model of acute myocardial infarction (AMI). Wistar rats were orally treated with BA or its vehicle for 28 days, anesthetized and randomized to three different groups (vehicle + ischemia/reperfusion (I/R), BA + I/R, and positive control vehicle + ischemic preconditioning (IPC)) and subjected to cardiac 30 min ischemia and 120 min reperfusion. IPC was performed by 3 × 5 min I/R cycles before ischemia. Myocardial function, area at risk, infarct size and arrhythmias were analyzed. Chronic BA pretreatment did not influence cardiac function or infarct size as compared to the vehicle group, while the positive control IPC significantly reduced the infarct size. The incidence of reperfusion-induced arrhythmias was significantly reduced by BA and IPC. This is the first demonstration that BA treatment does not show cardioprotective effect although moderately reduces the incidence of reperfusion-induced arrhythmias. Furthermore, BA does not show hidden cardiotoxic effect in rats with AMI, showing its safety in the ischemic/reperfused heart.

Bempedoic acid and its role in contemporary management of hyperlipidemia in atherosclerosis

Atherosclerotic heart disease is the leading cause of mortality and morbidity in the USA. Low density lipoprotein (LDL) has been the target for many hypolipidemic agents to modify atherosclerotic risk. Bempedoic acid is a novel hypolipidemic drug that inhibits the enzymatic activity of ATP citrate lyase in the cholesterol synthesis pathway. CLEAR Harmony, CLEAR Wisdom, CLEAR Tranquillity and CLEAR Serenity have shown safety and efficacy associated with long term administration of this drug. Studies have shown effectiveness in reducing LDL-C in both statin intolerant patients and in patients on maximally tolerated doses of statin. The fixed drug combination of bempedoic acid and ezetimibe in a recent phase III showed significant reduction in LDL compared with placebo, which might be a promising future for LDL reduction among statin intolerant patients. Bempedoic acid also reduced inflammatory markers like hs-CRP. Given these results, bempedoic acid alone and in combination with ezetimibe received the USA FDA approval for adults with heterozygous familial hypercholesterolaemia or established atherosclerotic cardiovascular disease. We present a comprehensive review exploring the underlying mechanism, pre-clinical studies, and clinical trials of bempedoic acid and discuss the potential future role of the drug in treating hyperlipidaemia.

Mechanism of action and therapeutic use of bempedoic acid in atherosclerosis and metabolic syndrome

Bempedoic acid is a new cholesterol-lowering drug, which has recently received US FDA and EMA approval. This drug targets lipid and glucose metabolism as well as inflammation via downregulation of ATP-citrate lyase and upregulation of AMP-activated protein kinase (AMPK). The primary effect is the reduction of cholesterol synthesis in the liver and its administration is generally not associated to unwanted muscle effects. Suppression of hepatic fatty acid synthesis leads to decreased triglycerides and, possibly, improved non-alcoholic fatty liver disease. Bempedoic acid may decrease gluconeogenesis leading to improved insulin sensitivity, glucose metabolism, and metabolic syndrome. The anti-inflammatory action of bempedoic acid is mainly achieved via activation of AMPK pathway in the immune cells, leading to decreased plasma levels of C-reactive protein. Effects of bempedoic acid on atherosclerotic cardiovascular disease, type 2 diabetes and chronic liver disease have been assessed in randomized clinical trials but require further confirmation. Safety clinical trials in phase III indicate that bempedoic acid administration is generally well-tolerated in combination with statins, ezetimibe, or proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors to achieve low-density lipoprotein cholesterol targets. The aim of this narrative review on bempedoic acid is to explore the underlying mechanisms of action and potential clinical targets, present existing evidence from clinical trials, and describe practical management of patients.

Bempedoic Acid: for Whom and When

PURPOSE OF REVIEW

The aim of creating an orally active non-statin cholesterol-lowering drug was achieved with bempedoic acid, a small linear molecule providing both a significant low-density lipoprotein cholesterol (LDL-C) reduction and an anti-inflammatory effect by decreasing high-sensitivity C-reactive protein. Bempedoic acid antagonizes ATP citrate-lyase, a cytosolic enzyme upstream of HMGCoA reductase which is the rate-limiting step of cholesterol biosynthesis. Bempedoic acid is a pro-drug converted to its active metabolite by very-long-chain acyl-CoA synthetase 1 which is present mostly in the liver and absent in skeletal muscles. This limits the risk of myalgia and myopathy. The remit of this review is to give clinical insights on the safety and efficacy of bempedoic acid and to understand for whom it should be prescribed.

RECENT FINDINGS

Bempedoic acid with a single daily dose (180 mg) reduces LDL-C by a mean 24.5% when given alone, by 18% when given on top of a major statin and by 38-40% when given in a fixed-dose combination with ezetimibe. Bempedoic acid does not lead to the risk of new-onset diabetes, and moderately improves the glycaemic profile. The extensive knowledge on bempedoic acid mechanism, metabolism and side effects has led to an improved understanding of the potential benefits of this agent and offers a possible alternative to cardiologists and clinical practitioners somewhat worn out today by the occurrence of the muscular side effects of statins.

Discovery and characterization of novel ATP citrate lyase inhibitors from natural products by a luminescence-based assay

ATP citrate lyase (ACLY) is a key enzyme in glucolipid metabolism with therapeutic prospect for treating hyperlipidemia and various cancers. Much effort has been put into discovering ACLY inhibitors. However, current screening approaches have limitations in sensitivity, portability and high-throughput. To develop a general screening assay, we investigated series of conditions affecting the enzymatic reaction based on the ADP-Glo luminescence assay. Bovine serum albumin (0.001%) added triggered strong and stable fluorescence signal. The optimized assay was validated and applied to screen our natural product library. Two novel inhibitors were identified with IC₅₀ values of 3.86 ± 0.62 μM (2) and 15.48 ± 2.51 μM (4). Their aggregations and target specificities were also examined. 2 was characterized as a noncompetitive inhibitor of ACLY, while 4 was a competitive inhibitor of CoA, which was also elucidated by docking studies. In anticancer activity evaluation, 2 with higher inhibition potency did not exhibit anticancer effect, probably owing to its insufficient cell-permeability. 4 showed moderate inhibition in the proliferation of A549 and PC3 cells. This study not only developed a general approach for ACLY inhibitor discovery, but also identified a new scaffold ACLY inhibitor, which could be served as a hit compound in drug design.

Discovery of Flavonoids as Novel Inhibitors of ATP Citrate Lyase: Structure–Activity Relationship and Inhibition Profiles

ATP citrate lyase (ACLY) is a key enzyme in glucolipid metabolism and its aberrantly high expression is closely associated with various cancers, hyperlipemia and atherosclerotic cardiovascular diseases. Prospects of ACLY inhibitors as treatments of these diseases are excellent. To date, flavonoids have not been extensively reported as ACLY inhibitors. In our study, 138 flavonoids were screened and 21 of them were subjected to concentration–response curves. A remarkable structure–activity relationship (SAR) trend was found: ortho-dihydroxyphenyl and a conjugated system maintained by a pyrone ring were critical for inhibitory activity. Among these flavonoids, herbacetin had a typical structure and showed a non–aggregated state in solution and a high inhibition potency (IC₅₀ = 0.50 ± 0.08 μM), and therefore was selected as a representative for the ligand–protein interaction study. In thermal shift assays, herbacetin improved the thermal stability of ACLY, suggesting a direct interaction with ACLY. Kinetic studies determined that herbacetin was a noncompetitive inhibitor of ACLY, as illustrated by molecular docking and dynamics simulation. Together, this work demonstrated flavonoids as novel and potent ACLY inhibitors with a remarkable SAR trend, which may help design high–potency ACLY inhibitors. In–depth studies of herbacetin deepened our understanding of the interactions between flavonoids and ACLY.

Unmet Need for Further LDL-C Lowering in India despite Statin Therapy: Lipid Association of India Recommendations for the Use of Bempedoic Acid

Lipid-lowering therapy plays a crucial role in reducing adverse cardiovascular (CV) events in patients with established atherosclerotic cardiovascular disease (ASCVD) and familial hypercholesterolemia. Lifestyle interventions along with high-intensity statin therapy are the first-line management strategy followed by ezetimibe. Only about 20-30% of patients who are on maximally tolerated statins reach recommended low-density lipoprotein cholesterol (LDL-C) goals. Several factors contribute to the problem, including adherence issues, prescription of less than high-intensity statin therapy, and de-escalation of statin dosages, but in patients with very high baseline LDL-C levels, including those with familial hypercholesterolemia and those who are intolerant to statins, it is critical to expand our arsenal of LDL-C-lowering medications. Moreover, in the extreme risk group of patients with an LDL-C goal of ≤30 mg/dL according to the Lipid Association of India (LAI) risk stratification algorithm, there is a significant residual risk requiring the addition of non-statin drugs to achieve LAI recommended targets. This makes bempedoic acid a welcome addition to the existing non-statin therapies such as ezetimibe, bile acid sequestrants, and PCSK9 inhibitors. A low frequency of muscle-related side effects, minimal drug interactions, a significant reduction in high-sensitivity C-reactive protein (hsCRP), and a lower incidence of new-onset or worsening diabetes make it a useful adjunct for LDL-C lowering. However, the CV outcomes trial results are still pending. In this LAI consensus document, we discuss the pharmacology, indications, contraindications, advantages, and evidence-based recommendations for the use of bempedoic acid in clinical practice.

Emerging roles of fatty acid metabolism in cancer and their targeted drug development

Metabolic reprogramming is now considered as one of hallmark of tumor cells and provides them with a selective survival/growth advantage to resist harsh micro-environmental stress. Fatty acid (FA) metabolism of tumor cells supports the biosynthetic needs and provides fuel sources for energy supply. Since FA metabolic reprogramming is a critical link in tumor metabolism, its various roles in tumors have attracted increasing interest. Herein, we review the mechanisms through which cancer cells rewire their FA metabolism with a focus on the pathway of FA metabolism and its targeting drug development. The failure and successful cases of targeting tumor FA metabolism are expected to bypass the metabolic vulnerability and improve the efficacy of targeted therapy.

KHK, PNPLA3 and PPAR as Novel Targets for the Anti-Steatotic Action of Bempedoic Acid

Bempedoic acid (BemA) is an ATP-citrate lyase (ACLY) inhibitor used to treat hypercholesterolemia. We studied the anti-steatotic effect of BemA, and the mechanisms involved, in a model of fatty liver in female rats obtained through the administration of a high-fat diet supplemented with liquid fructose (HFHFr) for three months. In the third month, a group of rats was treated with BemA (30 mg/kg/day) by gavage. Plasma analytes, liver histology, adiposity, and the expression of key genes controlling fatty acid metabolism were determined, and PPAR agonism was explored by using luciferase reporter assays. Our results showed that, compared to HFHFr, BemA-treated rats exhibited lower body weight, higher liver/body weight, and reduced hepatic steatosis. In addition to ACLY inhibition, we found three novel mechanisms that could account for the anti-steatotic effect: (1) reduction of liver ketohexokinase, leading to lower fructose intake and reduced de novo lipogenesis; (2) increased expression of patatin-like phospholipase domain-containing protein 3, a protein related to the export of liver triglycerides to blood; and (3) PPARα agonist activity, leading to increased hepatic fatty acid β-oxidation. In conclusion, BemA may represent a novel approach to treat hepatic steatosis, and therefore to avoid progression to advanced stages of non-alcoholic fatty liver disease.

Hydroxycitric Acid Inhibits Chronic Myelogenous Leukemia Growth through Activation of AMPK and mTOR Pathway

Metabolic regulation of cancer cell growth via AMP-activated protein kinase (AMPK) activation is a widely studied strategy for cancer treatment, including leukemias. Recent notions that naturally occurring compounds might have AMPK activity led to the search for nutraceuticals with potential AMPK-stimulating activity. We found that hydroxycitric acid (HCA), a natural, safe bioactive from the plant Garcinia gummi-gutta (cambogia), has potent AMPK activity in chronic myelogenous leukemia (CML) cell line K562. HCA is a known competitive inhibitor of ATP citrate lyase (ACLY) and is widely used as a weight loss inducer. We found that HCA was able to inhibit the growth of K562 cells in in vitro and in vivo xenograft models. At the mechanistic level, we identified a direct interaction between AMPK and ACLY that seems to be sensitive to HCA treatment. Additionally, HCA treatment resulted in the co-activation of AMPK and the mammalian target of rapamycin (mTOR) pathways. Moreover, we found an enhanced unfolded protein response as observed by activation of the eIF2α/ATF4 pathway that could explain the induction of cell cycle arrest at the G2/M phase and DNA fragmentation upon HCA treatment in K562 cells. Overall, these findings suggest HCA as a nutraceutical approach for the treatment of CMLs.

Inhibition of ATP-citrate lyase improves NASH, liver fibrosis, and dyslipidemia

Elevated liver de novo lipogenesis contributes to non-alcoholic steatohepatitis (NASH) and can be inhibited by targeting acetyl-CoA carboxylase (ACC). However, hypertriglyceridemia limits the use of pharmacological ACC inhibitors as a monotherapy. ATP-citrate lyase (ACLY) generates acetyl-CoA and oxaloacetate from citrate, but whether inhibition is effective for treating NASH is unknown. Here, we characterize a new mouse model that replicates many of the pathological and molecular drivers of NASH and find that genetically inhibiting ACLY in hepatocytes reduces liver malonyl-CoA, oxaloacetate, steatosis, and ballooning as well as blood glucose, triglycerides, and cholesterol. Pharmacological inhibition of ACLY mirrors genetic inhibition but has additional positive effects on hepatic stellate cells, liver inflammation, and fibrosis. Mendelian randomization of human variants that mimic reductions in ACLY also associate with lower circulating triglycerides and biomarkers of NASH. These data indicate that inhibiting liver ACLY may be an effective approach for treatment of NASH and dyslipidemia.

Estimated cardiovascular benefits of bempedoic acid in patients with established cardiovascular disease

Background and aims

Cardiovascular outcomes trials have demonstrated that lowering low-density lipoprotein cholesterol (LDL-C) reduces the risk for future cardiovascular events. We assessed the potential cardiovascular benefits of bempedoic acid through a simulation study in patients with atherosclerotic cardiovascular disease (ASCVD) and elevated LDL-C.

Methods

The validated SMART prediction model was used to estimate the baseline 10-year risk of three-point major adverse cardiovascular events (cardiovascular death, non-fatal myocardial infarction, and non-fatal stroke) in patients with ASCVD who were enrolled in four Phase 3, randomized, placebo-controlled bempedoic acid studies. The predicted change in 10-year cardiovascular risk associated with bempedoic acid was estimated for each patient based on the Cholesterol Treatment Trialists' model. Data were analyzed in two cohorts: Cohort 1 included mostly patients treated with moderate-high intensity statins, and Cohort 2 included patients who were intolerant of more than low-intensity statin.

Results

A total of 2884 patients were included in Cohort 1 and 226 in Cohort 2. Weighted average baseline 10-year cardiovascular event risk was 26.1% and 31.6% for Cohorts 1 and 2, respectively. The least squares mean percent difference (95% confidence interval (CI) of the predicted absolute change in 10-year cardiovascular event risk with bempedoic acid was -3.3% (-3.7% to -2.9%) for patients in Cohort 1 and -6.0% (-7.7% to -4.3%) for patients in Cohort 2 compared with placebo (p < 0.0001 for both).

Conclusions

Among patients with ASCVD who could potentially benefit from additional LDL-C lowering, our simulation predicted a lower absolute cardiovascular event risk after initiating bempedoic acid as compared with placebo.

Bempedoic Acid: A New Tool for LDL-Cholesterol Control in Patients with Coronary Artery Disease

Nowdays a small proportion of patients with high/very high/extreme atherosclerotic cardiovascular disease risk achieves the optimal target of LDL-cholesterol, because of drug intolerance, poor adherence to the therapy, or inapplicability of the stepwise strategy in lipid lowering therapy, recommended by the current guidelines. The new oral agent bempedoic acid lowers plasma LDL-cholesterol by inhibiting adenosine triphosphate-citrate lyase, an enzyme involved in the synthesis of cholesterol, and, ultimately, by up-regulating the LDL receptors. Several clinical trials in patients with atherosclerotic cardiovascular disease or familial heterozygous hypercholesterolemia demonstrated that bempedoic acid alone or combined with statins and/or ezetimibe significantly reduced LDL-cholesterol and high-sensitivity C-reactive protein. Bempedoic acid is well tolerated with no significant increase in muscle-related symptoms, since it can be activated only in the liver but not in the skeletal muscles. Bempedoic acid provides an effective tool to further reduce LDL-cholesterol as add on therapy in patients unable to reach the target despite maximally tolerated lipid lowering therapy.

Bempedoic acid in patients with type 2 diabetes mellitus, prediabetes, and normoglycaemia: A post hoc analysis of efficacy and glycaemic control using pooled data from phase 3 clinical trials

AIM

To evaluate the effect of bempedoic acid on glycaemic and lipid variables in patients with hypercholesterolaemia.

METHODS

A patient-level pooled analysis of four phase 3, randomized, double-blind, placebo-controlled trials evaluated changes in glycaemia, change from baseline in LDL-C, and adverse events. Patients (N = 3621) on maximally tolerated statins were randomized 2:1 to oral bempedoic acid 180 mg or placebo once daily for 12 to 52 weeks with the results analysed by baseline glycaemic status (diabetes, prediabetes, or normoglycaemia).

RESULTS

The annual rate of new-onset diabetes for bempedoic acid versus placebo in patients with normoglycaemia at baseline (n = 618) was 0.3% versus 0.8%, and for patients with prediabetes at baseline (n = 1868) it was 4.7% versus 5.9%. In patients with diabetes or prediabetes, bempedoic acid significantly (P < .0001) reduced HbA1c by -0.12% and -0.06%, respectively, and did not worsen fasting glucose versus placebo. Bempedoic acid significantly and consistently lowered LDL-C levels versus placebo, regardless of baseline glycaemic status (placebo-corrected difference range, -17.2% to -29.6%; P < .001 for each stratum). The safety of bempedoic acid was comparable with placebo and similar across glycaemic strata.

CONCLUSIONS

Bempedoic acid significantly lowered LDL-C across glycaemic strata and did not worsen glycaemic variables or increase the incidence of new-onset diabetes versus placebo over a median follow-up of 1 year.

New Treatment Targets and Innovative Lipid-Lowering Therapies in Very-High-Risk Patients with Cardiovascular Disease

The effective and fast reduction of circulating low-density lipoprotein cholesterol (LDL-C) is a cornerstone for secondary prevention of atherosclerotic disease progression. Despite the substantial lipid-lowering effects of the established treatment option with statins and ezetimibe, a significant proportion of very-high-risk patients with cardiovascular disease do not reach the recommended treatment goal of <55 mg/dL (<1.4 mmol/L). Novel lipid-lowering agents, including the proprotein convertase subtilisin/kexin type 9 (PCSK9) antibodies alirocumab and evolocumab, the small interfering ribonucleotide acid (si-RNA) inclisiran, as well as the recently approved bempedoic acid, now complete the current arsenal of LDL-C lowering agents. These innovative therapies have demonstrated promising results in clinical studies. Besides a strong reduction of LDL-C by use of highly effective agents, there is still discussion as to whether a very rapid achievement of the treatment goal should be a new strategic approach in lipid-lowering therapy. In this review, we summarize evidence for the lipid-modifying properties of these novel agents and their safety profiles, and discuss their potential pleiotropic effects beyond LDL-C reduction (if any) as well as their effects on clinical endpoints as cardiovascular mortality. In addition to a treatment strategy of “the lower, the better”, we also discuss the concept of “the earlier, the better”, which may also add to the early clinical benefit of large LDL-C reduction after an acute ischemic event.

ATP-citrate lyase (ACLY) inhibitors as therapeutic agents: a patenting perspective

INTRODUCTION

ATP citrate lyase (ACLY) is a key enzyme in cellular metabolism, being the main source of acetyl-Coenzyme A, an important precursor for fatty acid, cholesterol and isoprenoid biosynthesis, and it is also involved in protein acetylation. Its expression changes are related to hyperlipidemia and cardiovascular diseases. Other studies have shown that ACLY is closely related to the occurrence of cancer: the increase in lipid synthesis provides the necessary building blocks for cell growth and division. Therefore, finding effective ACLY inhibitors has very important application prospects for lipid-related pathologies and cancer.

AREAS COVERED

: This review covers patents concerning ACLY inhibitors and alternative strategies to modulate ACLY activity, with their potential therapeutic applications.

EXPERT OPINION

In recent years ACLY as a drug target has become a hot spot in the research of innovative drugs for disorders of glucose and lipid metabolism. Many types of small-molecule ACLY inhibitors have been discovered, but few ACLY inhibitors proved to be highly effective in vitro and in vivo, since their main limitations were low cell penetration and low affinity to ACLY. The search for new effective ACLY inhibitors is of great significance and has broad application prospects for the treatment of hyperlipidemia and cancer.

Novel Pharmaceutical and Nutraceutical-Based Approaches for Cardiovascular Diseases Prevention Targeting Atherogenic Small Dense LDL

Compelling evidence supports the causative link between increased levels of low-density lipoprotein cholesterol (LDL-C) and atherosclerotic cardiovascular disease (CVD) development. For that reason, the principal aim of primary and secondary cardiovascular prevention is to reach and sustain recommended LDL-C goals. Although there is a considerable body of evidence that shows that lowering LDL-C levels is directly associated with CVD risk reduction, recent data shows that the majority of patients across Europe cannot achieve their LDL-C targets. In attempting to address this matter, a new overarching concept of a lipid-lowering approach, comprising of even more intensive, much earlier and longer intervention to reduce LDL-C level, was recently proposed for high-risk patients. Another important concern is the residual risk for recurrent cardiovascular events despite optimal LDL-C reduction, suggesting that novel lipid biomarkers should also be considered as potential therapeutic targets. Among them, small dense LDL particles (sdLDL) seem to have the most significant potential for therapeutic modulation. This paper discusses the potential of traditional and emerging lipid-lowering approaches for cardiovascular prevention by targeting sdLDL particles.

New insights into the role of bempedoic acid and ezetimibe in the treatment of hypercholesterolemia

PURPOSE OF REVIEW

A number of new cholesterol-lowering drugs have been recently developed and approved, enriching the pharmacological armamentarium beyond and above statins. Ezetimibe, available since two decades, and bempedoic acid, a new drug inhibiting the same biosynthetic pathway targeted by statins but at an early step, represent valuable tools for the treatment of hypercholesterolemia, particularly in specific groups of patients.

RECENT FINDINGS

Bempedoic acid, either alone or in combination with ezetimibe, appears to reduce significantly LDL-C levels, an effect that has been observed also in patients with statin intolerance. A Mendelian randomization study has anticipated a protective cardiovascular effect of bempedoic acid; a randomized clinical trial is currently assessing whether the pharmacological control of hypercholesterolemia with bempedoic acid translates into a clinical benefit. Bempedoic acid, as well as ezetimibe, does not appear to induce adverse events in muscles; moreover, whereas statins are associated with a modest, although significant, increased risk of new-onset diabetes, bempedoic acid does not, at least based on the available evidence.

SUMMARY

On the basis of available data, and while awaiting the results of the outcome trial, bempedoic acid appears to represent a valuable approach for the treatment of hypercholesterolemia, either alone or in combination in ezetimibe.

A Nutrient-Based Cellular Model to Characterize Acetylation-Dependent Protein-Protein Interactions

Cellular homeostasis requires the orderly expression of thousands of transcripts. Gene expression is regulated by numerous proteins that recognize post-translational modifications—in particular, the acetylation of lysine residues (Kac) on histones. In addition to affecting the general condensation state of the chromatin, acetylated histones act as anchor points for bromodomain (BRD)-containing adapter proteins. BRDs are the primary Kac reader domains in humans, and proteins containing them act as chromatin scaffolds that organize large networks of interactions to regulate transcription. To characterize BRD-dependent interaction networks, we established cell lines in which histone acetylation is dependent on acetate supplementation. To do this, we used genome editing to knock out ATP citrate lyase (ACLY), the enzyme responsible for converting citrate to oxaloacetate and acetyl-CoA in the cytoplasm and nucleus. In our cellular model, removing acetate from the culture medium resulted in the rapid catabolism of acetylated histones to restore the nucleocytoplasmic acetyl-CoA pool. Here we report the use of our new model in functional proteomics studies to characterize BRD-dependent interaction networks on the chromatin.

Bempedoic acid as a PPARα activator: new perspectives for hepatic steatosis treatment in a female rat experimental model

INTRODUCTION

In its initial stages, nonalcoholic fatty liver disease presents hypertriglyceridemia and accumulation of lipids in the liver (hepatic steatosis). Bempedoic acid is an ATP:citrate lyase inhibitor that promotes a dual inhibition of the synthesis of cholesterol and fatty acids. However, its effect in the prevention / treatment of hepatic steatosis and hypertriglyceridemia has not been investigated. The aim of our work has been to elucidate whether bempedoic acid, through a mechanism other than ATP:citrate lyase inhibition, reverses these metabolic alterations.

EXPERIMENTAL DESIGN

The study was carried out in female Sprague-Dawley rats fed, for three months, with a high fat diet supplemented with fructose (10% w/v) in drinking water. During the last month, bempedoic acid (30mg/kg/day) was administered to a group of animals. Zoometric and plasmatic parameters were analyzed, gene and protein expression analysis were performed in liver samples and PPAR-PPRE binding activity was determined.

RESULTS

Our interventional model developed hepatic steatosis and hypertriglyceridemia. Despite an increase in total caloric intake, there was no increase in body weight of the animals. The administration of bempedoic acid significantly reduced hepatic steatosis and promoted a marked hepatocyte hypertrophy. There was a 66% increase in the liver weight of the animals treated with the drug that was not accompanied by modifications in the markers of inflammation, oxidative stress, or endoplasmic reticulum stress. Bempedoic acid activated the peroxisome proliferator activated nuclear receptor (PPARα) and its target genes.

CONCLUSIONS

Bempedoic acid could be an effective therapy for the treatment of fatty liver and associated cardiovascular risk. Bempedoic acid has other mechanisms of action besides the inhibition of ATP: citrate lyase, such as the activation of PPARα, which could explain the reduction in hepatic steatosis and the increase in liver weight observed in animals treated with the drug.

Role of Lipogenesis Rewiring in Hepatocellular Carcinoma

Metabolic rewiring is one of the hallmarks of cancer. Altered de novo lipogenesis is one of the pivotal metabolic events deregulated in cancers. Sterol regulatory element-binding transcription factor 1 (SREBP1) controls the transcription of major enzymes involved in de novo lipogenesis, including ACLY, ACACA, FASN, and SCD. Studies have shown the increased de novo lipogenesis in human hepatocellular carcinoma (HCC) samples. Multiple mechanisms, such as activation of the AKT/mechanistic target of rapamycin (mTOR) pathway, lead to high SREBP1 induction and the coordinated enhanced expression of ACLY, ACACA, FASN, and SCD genes. Subsequent functional analyses have unraveled these enzymes' critical role(s) and the related de novo lipogenesis in hepatocarcinogenesis. Importantly, targeting these molecules might be a promising strategy for HCC treatment. This paper comprehensively summarizes de novo lipogenesis rewiring in HCC and how this pathway might be therapeutically targeted.

The dawn of a new era of targeted lipid-lowering therapies

Lipid risk factors for cardiovascular disease depend in part on lifestyle, but optimum control of lipids often demands additional measures. Low-density lipoprotein (LDL) doubtless contributes causally to atherosclerosis. Recent human genetic findings have substantiated a number of novel targets for lipid-lowering therapy including apolipoprotein C-III, angiopoietin-like protein 3 and 4, apolipoprotein V, and ATP citrate lyase. These discoveries coupled with advances in biotechnology development afford new avenues for management of LDL and other aspects of lipid risk. Beyond LDL, new treatments targeting triglyceride-rich lipoproteins and lipoprotein(a) have become available and have entered clinical development. Biological and RNA-directed agents have joined traditional small-molecule approaches, which themselves have undergone considerable refinement. Innovative targeting strategies have increased efficacy of some of these novel interventions and markedly improved their tolerability. Gene-editing approaches have appeared on the horizon of lipid management. This article reviews this progress offering insight into novel biological and therapeutic discoveries, and places them into a practical patient care perspective.

Lipogenesis inhibitors: therapeutic opportunities and challenges

Fatty acids are essential for survival, acting as bioenergetic substrates, structural components and signalling molecules. Given their vital role, cells have evolved mechanisms to generate fatty acids from alternative carbon sources, through a process known as de novo lipogenesis (DNL). Despite the importance of DNL, aberrant upregulation is associated with a wide variety of pathologies. Inhibiting core enzymes of DNL, including citrate/isocitrate carrier (CIC), ATP-citrate lyase (ACLY), acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS), represents an attractive therapeutic strategy. Despite challenges related to efficacy, selectivity and safety, several new classes of synthetic DNL inhibitors have entered clinical-stage development and may become the foundation for a new class of therapeutics.

De novo lipogenesis (DNL) is vital for the maintenance of whole-body and cellular homeostasis, but aberrant upregulation of the pathway is associated with a broad range of conditions, including cardiovascular disease, metabolic disorders and cancers. Here, Steinberg and colleagues provide an overview of the physiological and pathological roles of the core DNL enzymes and assess strategies and agents currently in development to therapeutically target them.

Atherosclerosis: Pathogenesis and Key Cellular Processes, Current and Emerging Therapies, Key Challenges, and Future Research Directions

Atherosclerosis is the principal cause of cardiovascular disease that continues to be a substantial drain on healthcare systems, being responsible for about 31% of all global deaths. Atherogenesis is influenced by a range of factors, including oxidative stress, inflammation, hypertension, and hyperlipidemia, and is ultimately driven by the accumulation of low-density lipoprotein cholesterol within the arterial wall of medium and large arteries. Lipoprotein accumulation stimulates the infiltration of immune cells (such as monocytes/macrophages and T-lymphocytes), some of which take up the lipoprotein, leading to the formation of lipid-laden foam cells. Foam cell death results in increased accumulation of dead cells, cellular debris and extracellular cholesterol, forming a lipid-rich necrotic core. Vascular smooth muscle cells from the arterial media also migrate into the intima layer and proliferate, taking up the available lipids to become foam cells and producing extracellular matrix proteins such as collagen and elastin. Plaque progression is characterized by the formation of a fibrous cap composed of extracellular matrix proteins and smooth muscle cells, which acts to stabilize the atherosclerotic plaque. Degradation, thinning, and subsequent rupture of the fibrous cap leads to lumen-occlusive atherothrombosis, most commonly resulting in heart attack or stroke. This chapter describes the pathogenesis of atherosclerosis, current and emerging therapies, key challenges, and future directions of research.

Clinical evaluation of bempedoic acid for the treatment of hyperlipidaemia

Bempedoic acid (BA) is a novel first-in-class oral lipid-lowering therapy. BA has been approved by the European Medicinal Agency and Food and Drug Administration and has been commercialised throughout Europe since the end of 2020 as an add-on therapy in patients at high/very-high cardiovascular risk that are not at LDL-C goals with current lipid-lowering treatments. Recently, Italian lipid management experts gathered to discuss several open questions on BA characteristics and BArelated practical clinical issues. The panel permitted collection of its opinions in a ten Q&A format.

AIM

The aim of this viewpoint is to discuss and answer several open questions on BA characteristics and BA-related practical clinical issues.

DATA SYNTHESIS

The data includes main phase III studies, subanalysis and meta-analysis on BA.

CONCLUSIONS

The panel permitted collection of its opinions in a ten Q&A format.

Key Roles of Inflammation in Atherosclerosis: Mediators Involved in Orchestrating the Inflammatory Response and Its Resolution in the Disease Along with Therapeutic Avenues Targeting Inflammation

Inflammation is a critical driver of all stages of atherosclerosis, from lesion development to plaque rupture. Cytokines are mediators of the immune response and in atherosclerosis, the balance of anti- and pro-inflammatory cytokines is tipped in favor of the latter, resulting in persistent and unresolved inflammation. Although reducing plasma cholesterol levels mainly via the use of statins has positively impacted patient outcomes and reduced mortality rates, the presence of significant residual inflammation and cardiovascular risk posttherapy emphasizes the prevailing risk of primary and secondary events driven by inflammation independently of hyperlipidemia. Given the dominant role of inflammation in driving pathogenesis, alternative therapeutic avenues beyond targeting lowering of plasma lipids are required. This chapter will discuss the role of inflammation and pro-inflammatory cytokines in driving atherogenesis and disease progression, the therapeutic potential of targeting cytokines for atherosclerosis and promising avenues in this area.

ATP citrate lyase inhibitor Bempedoic Acid alleviate long term HFD induced NASH through improvement in glycemic control, reduction of hepatic triglycerides & total cholesterol, modulation of inflammatory & fibrotic genes and improvement in NAS score

Non-alcoholic fatty liver disease (NAFLD) and Non-alcoholic steatohepatitis (NASH) are chronic liver disorders, the prevalence of which is increasing worldwide. Long term High Fat Diet (HFD) induced NASH animal models closely mimic the characteristics of human NASH and hence used by investigators as a model system for studying the mechanism of action of new drugs. Bempedoic acid (ETC-1002), a ATP citrate lyase (ACLY) inhibitor that lowers the LDL cholesterol was recently approved by US FDA for the treatment of heterozygous familial hypercholesterolemia (HeFH) and established atherosclerotic cardiovascular disease (ASCVD). ACLY is one of the genes modulated in NASH patients and hence we studied the effect of ACLY inhibitor Bempedoic acid in long term HFD induced NASH animal model to understand the pharmacological benefits and the associated mechanism of action of this newly approved drug in NASH. Mice fed with 60% Kcal High Fat Diet for 32 weeks were used for the study and the animals were given Bempedoic acid for 5 weeks at doses of 10 ​mg ​kg⁻¹, po, qd, and 30 ​mg ​kg⁻¹, po, qd. Bempedoic acid treatment resulted in inhibition of body weight gain and improved the glycemic control. Bempedoic acid treated group showed statistically significant reduction in plasma ALT, AST, hepatic triglycerides (TG) and total cholesterol (TC), along with statistically significant reduction in steatosis score by histological analysis. Hepatic gene expression analysis showed significant reduction in inflammatory and fibrotic genes such as Mcp-1/Ccl2, Timp-1 & Col1α1. Histological analysis showed significant improvement in NAS score. Overall, Bempedoic acid alleviated HFD induced Non-Alcoholic Steatohepatitis through inhibition of body weight gain, improvement in glycemic control, reduction of hepatic triglycerides & total cholesterol, modulation of inflammatory & fibrotic genes, and improvement in NAS score. Hence, Bempedoic acid can be a potential therapeutic option for metabolic syndrome and NASH.

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Bempedoic acid alleviated HFD induced Non-Alcoholic Steatohepatitis in a long term HFD induced NASH animal model.

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Mechanism of action includes modulation of lipid profile, inflammatory & fibrotic genes and inhibition of body weight gain.

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Overall improvement in NAS score was observed with Bempedoic acid treatment.

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Our study shows a promising role for Bempedoic acid in amelioration of metabolic disorders and NASH.

Targeting cancer metabolism in the era of precision oncology

One hundred years have passed since Warburg discovered alterations in cancer metabolism, more than 70 years since Sidney Farber introduced anti-folates that transformed the treatment of childhood leukaemia, and 20 years since metabolism was linked to oncogenes. However, progress in targeting cancer metabolism therapeutically in the past decade has been limited. Only a few metabolism-based drugs for cancer have been successfully developed, some of which are in - or en route to - clinical trials. Strategies for targeting the intrinsic metabolism of cancer cells often did not account for the metabolism of non-cancer stromal and immune cells, which have pivotal roles in tumour progression and maintenance. By considering immune cell metabolism and the clinical manifestations of inborn errors of metabolism, it may be possible to isolate undesirable off-tumour, on-target effects of metabolic drugs during their development. Hence, the conceptual framework for drug design must consider the metabolic vulnerabilities of non-cancer cells in the tumour immune microenvironment, as well as those of cancer cells. In this Review, we cover the recent developments, notable milestones and setbacks in targeting cancer metabolism, and discuss the way forward for the field.

An update on emerging drugs for the treatment of hypercholesterolemia

INTRODUCTION

Elevated levels of low-density lipoprotein (LDL) cholesterol have been unequivocally demonstrated to play a causal role in atherosclerotic cardiovascular disease. The last thirty years have witnessed a generation of clinical trials that have demonstrated a reduction in cardiovascular risk with the use of increasing intensive lipid lowering regimens involving statin therapy in combination with other agents. However, many patients fail to achieve treatment mandated LDL cholesterol goals. This highlights the need to develop additional approaches to lower LDL cholesterol levels.

AREAS COVERED

(i) Contemporary data highlighting the atherogenicity of LDL cholesterol and cardiovascular benefits of current lipid lowering therapies. (ii) Importance of statin intolerance and inability to achieve LDL cholesterol goals in driving ongoing cardiovascular risk. (iii) Emergence of new therapeutic agents designed to achieve more effective lowering of LDL cholesterol.

EXPERT OPINION

Effective lowering of LDL cholesterol plays a critical role in approaches to the prevention of cardiovascular disease. A greater number of patients will require combinations of agents to achieve optimal lipid control. Accordingly, new agents will be required to provide sufficient choice for patients at high cardiovascular risk.

Role of Vitamin B12 and Folate in Metabolic Syndrome

Metabolic syndrome (MS) is a collection of pathological metabolic conditions that includes insulin resistance, central or abdominal obesity, dyslipidemia, and hypertension. It affects large populations worldwide, and its prevalence is rising exponentially. There is no specific mechanism that leads to the development of MS. Proposed hypotheses range from visceral adiposity being a key factor to an increase in very-low-density lipoprotein and fatty acid synthesis as the primary cause of MS. Numerous pharmaceutical therapies are widely available in the market for the treatment of the individual components of MS. The relationship between MS and vitamin B complex supplementation, specifically folic acid and vitamin B12, has been a subject of investigation worldwide, with several trials reporting a positive impact with vitamin supplementation on MS.

In this study, an all-language literature search was conducted on Medline, Cochrane, Embase, and Google Scholar till September 2021. The following search strings and Medical Subject Headings (MeSH) terms were used: “Vitamin B12,” “Folate,” “Metabolic Syndrome,” and “Insulin Resistance.” We explored the literature on MS for its epidemiology, pathophysiology, newer treatment options, with a special focus on the effectiveness of supplementation with vitamins B9 and B12.

According to the literature, vitamin B12 and folate supplementation, along with a host of novel therapies, has a considerable positive impact on MS. These findings must be kept in mind while designing newer treatment protocols in the future.

Liver Fibrosis and MAFLD: From Molecular Aspects to Novel Pharmacological Strategies

Metabolic-associated fatty liver disease (MAFLD) is a new disease definition, and this nomenclature MAFLD was proposed to renovate its former name, non-alcoholic fatty liver disease (NAFLD). MAFLD/NAFLD have shared and predominate causes from nutrition overload to persistent liver damage and eventually lead to the development of liver fibrosis and cirrhosis. Unfortunately, there is an absence of effective treatments to reverse MAFLD/NAFLD-associated fibrosis. Due to the significant burden of MAFLD/NAFLD and its complications, there are active investigations on the development of novel targets and pharmacotherapeutics for treating this disease. In this review, we cover recent discoveries in new targets and molecules for antifibrotic treatment, which target pathways intertwined with the fibrogenesis process, including lipid metabolism, inflammation, cell apoptosis, oxidative stress, and extracellular matrix formation. Although marked advances have been made in the development of antifibrotic therapeutics, none of the treatments have achieved the endpoints evaluated by liver biopsy or without significant side effects in a large-scale trial. In addition to the discovery of new druggable targets and pharmacotherapeutics, personalized medication, and combinatorial therapies targeting multiple profibrotic pathways could be promising in achieving successful antifibrotic interventions in patients with MAFLD/NAFLD.

Oral Lipid-Lowering Treatments Beyond Statins: Too Old and Outdated or Still Useful?

Purpose of Review

For many years, the lipid-lowering armamentarium consisted of statins and/or ezetimibe and/or bile acid sequestrants and/or fibrates. Now, with the availability of new drugs mostly injectables, the field has changed and the role of oral non-statin drugs (including bempedoic acid) must be reevaluated.

Recent Findings

Ezetimibe remains a very important combination partner for statins with continuously increasing treatment numbers. Bempedoic acid is another interesting combination partner for statin/ezetimibe or ezetimibe alone but lacks in contrast to ezetimibe evidence from outcome trials. The role of fibrates is less clear as they have shown disappointing results in outcome trials but may still be used in selected, high-risk patients with combined dyslipidemia. Bile acid sequestrants are now rarely used as there are stronger, better tolerable ways to lower LDL-cholesterol.

Summary

With the introduction of new injectable lipid-lowering drugs, some oral drugs such as ezetimibe and bempedoic acid still have an important spot in our treatment algorithm others such as fibrates have a less clear role while again others are now rarely used.

The multifaceted therapeutic value of targeting ATP-citrate lyase in atherosclerosis

ATP-citrate lyase (Acly) is the target of the new class low-density lipoprotein-cholesterol (LDL-C)-lowering drug bempedoic acid (BA). Acly is a key metabolic enzyme synthesizing acetyl-CoA as the building block of cholesterol and fatty acids. Treatment with BA lowers circulating lipid levels and reduces systemic inflammation, suggesting a dual benefit of this drug for atherosclerosis therapy. Recent studies have shown that targeting Acly in macrophages can attenuate inflammatory responses and decrease atherosclerotic plaque vulnerability. Therefore, it could be beneficial to extend the application of Acly inhibition from solely lipid-lowering by liver-specific inhibition to also targeting macrophages in atherosclerosis. Here, we outline the possibilities of targeting Acly and describe the future needs to translate these findings to the clinic.

Bempedoic Acid: A New Non-statin Drug for the Treatment of Dyslipidemia

Statins are currently the first-line drugs for managing dyslipidemia due to their substantial clinical efficacy in reducing low-density lipoprotein cholesterol (LDL-C) and the risk of atherosclerotic cardiovascular disease (ASCVD). However, many patients do not reach their LDL-C target despite taking high-dose statins and some patients are intolerant of these drugs. Therefore, an additional or alternative pharmacological intervention may be required. Bempedoic acid is a novel lipid-lowering drug recently approved for the treatment of dyslipidemia. This review describes the pharmacology of bempedoic acid and its clinical role in patients with dyslipidemia. Bempedoic acid, via its active coenzyme A (CoA) form, inhibits adenosine triphosphate (ATP)-citrate lyase, and reduces hepatic cholesterol synthesis through the mevalonate pathway. The reduction in plasma LDL-C by bempedoic acid is approximately 20%. In addition, this drug is able to lower the level of high-sensitivity C-reactive protein (hs-CRP) by 20%, which suggests anti-inflammatory activity. Bempedoic acid is well tolerated by the majority of patients. Possible common adverse drug reactions include upper respiratory tract infection, urinary tract infection and arthralgia. Serum creatinine and uric acid should be monitored since increased creatinine and hyperuricemia-associated new onset of gout and gout flares have been reported in patients taking bempedoic acid. Decreased hemoglobin levels and rare tendon ruptures have also been observed. Due to its efficacy and good safety profile, bempedoic acid might serve as a potential therapeutic alternative for the management of dyslipidemia.

Role of Bempedoic Acid in Clinical Practice

Many patients do not achieve optimal low-density lipoprotein cholesterol (LDL-C) levels with statins alone; others are unable to tolerate statin therapy. Additional non-statin treatment options including ezetimibe, proprotein convertase subtilisin/kexin type 9 inhibitors, and bile acid sequestrants are often necessary to further reduce the risk of atherosclerotic cardiovascular disease. This review provides practical guidance as to the use of bempedoic acid to lower LDL-C and includes direction as to which patients may benefit and advice for safety monitoring during treatment. Bempedoic acid, a new class of agent, is a prodrug converted to bempedoyl-CoA by very long-chain acyl-CoA synthetase 1, an enzyme with high expression in the liver but that is undetectable in the skeletal muscle. Bempedoic acid inhibits the enzyme adenosine triphosphate (ATP)-citrate lyase, which lies two steps upstream from β-hydroxy β-methylglutaryl-CoA reductase in the cholesterol biosynthesis pathway. In clinical trials conducted in patients with or at risk for atherosclerotic cardiovascular disease or familial heterozygous hypercholesterolemia, bempedoic acid in combination with statins and/or ezetimibe significantly reduced LDL-C, apolipoprotein B, and high-sensitivity C-reactive protein compared with placebo. Bempedoic acid is generally well tolerated with no clinically meaningful increase in muscle-related symptoms relative to placebo, even in patients taking maximally tolerated statins. A small increase in serum uric acid (mean increase 0.8 mg/dL) is the most noteworthy adverse effect. Bempedoic acid provides an effective and generally well-tolerated medication to further reduce LDL-C in patients taking maximally tolerated statins or manage LDL-C levels in those who are unable to take statins. The potential for a reduced incidence of major cardiovascular events with bempedoic acid is being investigated in the CLEAR Outcomes trial, with results expected in 2023.

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.

Bempedoic Acid: The New Kid on the Block for the Treatment of Dyslipidemia and LDL Cholesterol: A Narrative Review

Diabetes is a major risk factor for atherosclerotic cardiovascular disease (ASCVD) in which dyslipidaemia plays a crucial role. Statins are first line therapy for primary and secondary prevention of ASCVD; however, adverse events include reversible musculoskeletal and liver side effects in addition to a diabetogenic association. In this short review, we provide a succinct narrative of the future role and current trial data of a novel first-in-class molecule, bempedoic acid. The authors provide their expert insight with a focus on Phase III randomised controlled trials (RCT) of bempedoic acid. Bempedoic acid was approved by the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) in February and March 2020, respectively, and is a novel molecule which inhibits cholesterol biosynthesis in the same mechanistic pathway as statins. It is a first-in-class small molecule, delivered as a prodrug and administered as an oral, once-daily dose that decreases low-density lipoprotein cholesterol (LDL-C) levels. Phase II and III RCTs have demonstrated efficacy with adequate safety data as mono- or combination therapy with statins and ezetimibe. Bempedoic acid is hepatically converted to the active drug with a lack of activation in skeletal muscle. Due to this novel mechanism, musculoskeletal-related adverse events exhibit a lower prevalence providing an alternative pharmacotherapy in statin-intolerant patients. Bempedoic acid may be used as an adjunct to diet and maximally tolerated statin therapy or in statin-intolerant patients for the treatment of dyslipidaemia. The recent National Institute of Health and Care Excellence (NICE) (UK) technology appraisal guidance [TA694] published in April 2021 recommended bempedoic acid with ezetimibe as a treatment option for primary hypercholesterolaemia or mixed dyslipidaemia if statins are not tolerated or contraindicated and if there is inadequate control of LDL-C with ezetimibe alone. Additionally, outcomes trials evaluating 'hard' endpoints in statin-intolerant patients or those with ASCVD are currently underway.

Lipid lowering with bempedoic acid added to a proprotein convertase subtilisin/kexin type 9 inhibitor therapy: A randomized, controlled trial

BACKGROUND

Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9is) lower low-density lipoprotein cholesterol (LDL-C) in patients with hypercholesterolemia. However, some patients receiving PCSK9i therapy might require additional lipid-lowering therapy (LLT) to reach LDL-C goals. Bempedoic acid is an oral, once-daily, ATP-citrate lyase inhibitor that significantly lowers LDL-C in patients with hypercholesterolemia when given alone or as add-on therapy to statins and/or ezetimibe.

OBJECTIVE

Assess safety and efficacy of bempedoic acid added to PCSK9i (evolocumab) background therapy in patients with hypercholesterolemia.

METHODS

This phase 2, randomized, double-blind, placebo-controlled study was conducted in three phases: 1.5-month screening/washout period including discontinuation of all LLTs, a 3-month period wherein patients initiated background PCSK9i therapy, and a 2-month treatment period in which patients were randomized 1:1 to receive bempedoic acid 180 mg or placebo once daily while continuing PCSK9i therapy.

RESULTS

Of 59 patients randomized, 57 completed the study. Mean baseline LDL-C after 3 months of PCSK9i background therapy was 103.1 ± ± 30.4 mg/dL. Bempedoic acid added to background PCSK9i therapy significantly lowered LDL-C by 30.3% (P < .001) vs placebo. Compared with placebo, bempedoic acid significantly lowered apolipoprotein B, non-high-density lipoprotein cholesterol, and total cholesterol (nominal P < .001 for all), and high-sensitivity C-reactive protein (P = .029). When added to background PCSK9i therapy, the safety profile of bempedoic acid was comparable to that observed for placebo.

CONCLUSIONS

When added to a background of PCSK9i therapy, bempedoic acid significantly lowered LDL-C levels with a safety profile comparable to placebo in patients with hypercholesterolemia.

Bempedoic Acid for Heterozygous Familial Hypercholesterolemia: From Bench to Bedside

Bempedoic acid is a first-in-class, oral, inhibitor of cholesterol biosynthesis that is approved for use in patients with atherosclerotic cardiovascular disease (ASCVD) and for primary prevention in individuals with heterozygous familial hypercholesterolemia (HeFH) by the United States Food and Drug Administration. Pooled data from the phase III clinical trials, CLEAR Harmony and CLEAR Wisdom, have demonstrated the safety and efficacy of bempedoic acid with regard to lowering of low-density lipoprotein cholesterol (LDL-C) in patients with HeFH as an adjunct or alternative to currently existing lipid-lowering therapies. CLEAR Outcomes is a cardiovascular outcomes trial that is currently underway that will provide additional insight as to where bempedoic acid will fit into treatment regimens among the non-statin lipid-lowering therapy options. Patients who might particularly benefit from bempedoic acid are those with HeFH and those unable to take adequate doses of statins or take any statin therapy altogether who need additional LDL-C lowering. In this review, we will discuss the profile of bempedoic acid from its design, development, and its place in therapy for the management of LDL-C for the purposes of ASCVD prevention.

Lipid metabolism in cancer: New perspectives and emerging mechanisms

Tumors undergo metabolic transformations to sustain uncontrolled proliferation, avoid cell death, and seed in secondary organs. An increased focus on cancer lipid metabolism has unveiled a number of mechanisms that promote tumor growth and survival, many of which are independent of classical cellular bioenergetics. These mechanisms include modulation of ferroptotic-mediated cell death, support during tumor metastasis, and interactions with the cells of the tumor microenvironment. As such, targeting lipid metabolism for anti-cancer therapies is attractive, with recent work on small-molecule inhibitors identifying compounds to target lipid metabolism. Here, we discuss these topics and identify open questions.

The interaction between the gut microbiota and dietary carbohydrates in nonalcoholic fatty liver disease

Imbalance between fat production and consumption causes various metabolic disorders. Nonalcoholic fatty liver disease (NAFLD), one such pathology, is characterized by abnormally increased fat synthesis and subsequent fat accumulation in hepatocytes1,2. While often comorbid with obesity and insulin resistance, this disease can also be found in lean individuals, suggesting specific metabolic dysfunction2. NAFLD has become one of the most prevalent liver diseases in adults worldwide, but its incidence in both children and adolescents has also markedly increased in developed nations3,4. Progression of this disease into nonalcoholic steatohepatitis (NASH), cirrhosis, liver failure, and hepatocellular carcinoma in combination with its widespread incidence thus makes NAFLD and its related pathologies a significant public health concern. Here, we review our understanding of the roles of dietary carbohydrates (glucose, fructose, and fibers) and the gut microbiota, which provides essential carbon sources for hepatic fat synthesis during the development of NAFLD.

Rationale and design of the CLEAR-outcomes trial: Evaluating the effect of bempedoic acid on cardiovascular events in patients with statin intolerance

Although statins play a pivotal role in the prevention of atherosclerotic cardiovascular disease, many patients fail to achieve recommended lipid levels due to statin-associated muscle symptoms. Bempedoic acid is an oral pro-drug that is activated in the liver and inhibits cholesterol synthesis in hepatocytes, but is not activated in skeletal muscle which has the potential to avoid muscle-related adverse events. Accordingly, this agent effectively lowers atherogenic lipoproteins in patients who experience statin-associated muscle symptoms. However, the effects of bempedoic acid on cardiovascular morbidity and mortality have not been studied. STUDY DESIGN: Cholesterol Lowering via Bempedoic acid, an ACL-Inhibiting Regimen (CLEAR) Outcomes is a randomized, double-blind, placebo-controlled clinical trial. Included patients must have all of the following: (i) established atherosclerotic cardiovascular disease or have a high risk of developing atherosclerotic cardiovascular disease, (ii) documented statin intolerance, and (iii) an LDL-C ≥100 mg/dL on maximally-tolerated lipid-lowering therapy. The study randomized 14,014 patients to treatment with bempedoic acid 180 mg daily or matching placebo on a background of guideline-directed medical therapy. The primary outcome is a composite of the time to first cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, or coronary revascularization. The trial will continue until 1620 patients experience a primary endpoint, with a minimum of 810 hard ischemic events (cardiovascular death, nonfatal myocardial infarction or nonfatal stroke) and minimum treatment duration of 36 months and a projected median treatment exposure of 42 months. CONCLUSIONS: CLEAR Outcomes will determine whether bempedoic acid 180 mg daily reduces the incidence of adverse cardiovascular events in high vascular risk patients with documented statin intolerance and elevated LDL-C levels.

Bempedoic acid. Mechanism of action and pharmacokinetic and pharmacodynamic properties

Bempedoic acid acts by inhibiting adenosine triphosphate-citrate lyase (ACL) and consequently cholesterol biosynthesis, leading to increased expression of LDL receptors and increasing low-density lipoproteins (LDL-C) plasma clearence. It is a prodrug for oral administration with intracellular activation. It is activatedin liver cells and to a lesser extent in kidney cells, being absent in adipose tissue and muscle cells. Therefore, unlike statins, its potential myotoxic effect is very limited. It has recently been approved as a lipid-lowering drug in combination with diet, with statins, or with other lipid-lowering drugs in patients with hypercholesterolaemia, mixed dyslipidaemia, statin intolerance, or when these are contraindicated. The marketing of bempedoic acid implies, in clinical practice, having a new family of lipid-lowering drugs.

Clinical development of bempedoic acid: phase 2 and phase 3 clinical trials

We review all the phase II and III studies carried out with bempedoic acid at the dose of 180mg, alone or in combination with different lipid-lowering drugs and in different subgroups of patients that unequivocally show the efficacy and safety of the drug. We point out some of the potential advantages of its use in clinical practice in patients with statin intolerance and the efficacy in reducing LDL-c when combined with statins, and with statins and ezetimibe, as well as in reducing inflammation markers pending the results of the CV Clear Outcomes trial that will end in 2022.

AMPK activator C24 inhibits hepatic lipogenesis and ameliorates dyslipidemia in HFHC diet-induced animal models

Dyslipidemia is a chronic metabolic disease characterized by elevated levels of lipids in plasma. Recently, various studies demonstrate that the increased activity of adenosine 5'-monophosphate-activated protein kinase (AMPK) causes health benefits in energy regulation. Thus, great efforts have been made to develop AMPK activators as a metabolic syndrome treatment. In the present study, we investigated the effects of the AMPK activator C24 on dyslipidemia and the potential mechanisms. We showed that C24 (5-40 μM) dose-dependently increased the phosphorylation of AMPKα and acetyl-CoA carboxylase (ACC), and inhibited lipogenesis in HepG2 cells. Using compound C, an AMPK inhibitor, or hepatocytes isolated from liver tissue-specific AMPK knockout AMPKα1α2fl/fl;Alb-cre mice (AMPK LKO), we demonstrated that the lipogenesis inhibition of C24 was dependent on hepatic AMPK activation. In rabbits with high-fat and high-cholesterol diet-induced dyslipidemia, administration of C24 (20, 40, and 60 mg · kg-1· d-1, ig, for 4 weeks) dose-dependently decreased the content of TG, total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C) in plasma and played a role in protecting against hepatic dysfunction by decreasing lipid accumulation. A lipid-lowering effect was also observed in high-fat and high-cholesterol diet-fed hamsters. In conclusion, our results demonstrate that the small molecular AMPK activator C24 alleviates hyperlipidemia and represents a promising compound for the development of a lipid-lowering drug.

Updated clinical evidence and place in therapy of bempedoic acid for hypercholesterolemia: ANMCO position paper

The central role of high low-density lipoprotein cholesterol levels in atherosclerotic cardiovascular disease has led to research focused on lipid-lowering agents for cardiovascular risk reduction. Bempedoic acid is an emerging treatment for hypercholesterolemia that has recently been approved for marketing in the United States and Europe. This review focuses on its mechanism of action and summarizes the main preclinical study findings. Furthermore, we report the clinical evidence supporting and guiding its use in hypercholesterolemia management.

Recent insights into low-density lipoprotein metabolism and therapy

PURPOSE OF REVIEW

Elevated levels of low-density lipoprotein cholesterol (LDL-C) are causal to atherosclerosis and, thus, the reduction of LDL-C represents a major objective for the prevention of cardiovascular disease. Aim of this review is to provide an overview on novel strategies to lower LDL-C.

RECENT FINDINGS

Although inhibiting liver cholesterol biosynthesis by statins is used as the main therapeutic approach to increase hepatic LDL-receptor expression and lower plasma cholesterol levels, novel insights into lipid and lipoprotein biology have led to the development of additional lipid-lowering therapies that can be used in combination with or as an alternative to statins in patients with statin-intolerance. New approaches include bempedoic acid, proprotein convertase subtilisin/kexin type 9 inhibitors, and angiopoietin-like protein 3 inhibitors.

SUMMARY

In the last decade, several novel therapeutic approaches have been tested and some of them have been approved as lipid-lowering agents. Some drugs are already available in clinical practice, whereas others are at late stages of development.