Recent advances in treating hypertriglyceridemia in patients at high risk of cardiovascular disease with apolipoprotein C-III inhibitors

Identification of Oxidative Stress-Related Genes in Hyperlipidemia Based on Bioinformatic Analysis

Oxidative stress (OS) is thought to mediate the processes of glycolipid disorders of a number of metabolic diseases and recent data suggest that OS may be involved in the pathophysiology of hyperlipidemia. The gene expression profiles of hyperlipidemia samples were downloaded from the Gene Expression Omnibus (GEO) database. Oxidative stress-related genes (ORGs) was the intersection of all valid data of discovery dataset and the ORGs in Genecards. The Differentially expressed genes (DEGs) between hyperlipidemia and control samples were obtained via "limma" R package, and differentially expressed oxidative stress-related genes (DEORGs) associated with hyperlipidemia were screened via OS gene sets. Gene Ontology (GO) and Kyoto encyclopaedia of Genes and Genomes (KEGG) enrichment analyses were performed to study the biological function of DEORGs, and protein-protein interaction (PPI) network analysis was conducted to screen hub genes. Then we constructed microRNA (miRNA), transcription factor (TF) and drug component targets network to explain the regulatory mechanism of ORGs in hyperlipidemia. After screening and evaluating we took GSE1010 as the discovery dataset and the GSE13985 as the validation set. There were 395 ORGs and 14 DEORGs retained from the hyperlipidemia. GO and KEGG results showed that DEORGs were mostly related to OS and lipid metabolism. Then, we used miRNA, TF, and drug component targets network to reveal the regulatory mechanism of hub genes. Finally, we verified expression of DEGs and hub gene in validation set. Our study has further confirmed the relationships between OS and hyperlipidemia, providing oxidative stress-related hub genes with possible function analysis and pathways summarized. These molecules might play a crucial role in the progression of hyperlipidemia and serve as potential biomarkers and therapeutic targets, giving us additional insight into the genes and the mechanism linking the OS system and metabolic disorders. We have not only proved hyperlipidemia is associated with OS but also gave foundation and reference for future researches.

Safety and Efficacy of the Novel RNA Interference Therapies for Hypertriglyceridemia and Mixed Hyperlipidemia Management: A Systematic Review and Meta-analysis

BACKGROUND

No meta-analysis has holistically analyzed and summarized the safety and therapeutic efficacy of the newer RNA interference (RNAi) therapies, olezarsen, plozasiran, and zodasiran, in managing conditions associated with hypertriglyceridemia (HTG).

METHODS

Randomized controlled trials (RCTs) involving patients with HTG or mixed hyperlipidemia (MHL) receiving either olezarsen, plozasiran, or zodasiran in the intervention arm and a placebo in the control arm were searched through electronic databases. The primary outcome was the safety profile of the drugs studied; secondary outcomes included the percent change from baseline (CFB) in the lipid levels, including triglyceride (TG).

RESULTS

Six RCTs with 334 participants were evaluated. Olezarsen, plozasiran, and zodasiran were well-tolerated with no higher risk of serious adverse events or injection-site reactions. After 24 weeks, plozasiran increased alanine aminotransferase and HbA1c more than placebo, although the difference was insignificant at 48 weeks. Plozasiran and zodasiran had little effect on hyperglycemia worsening. Olezarsen increased the likelihood of mild platelet count decreases without clinical harm. At their longest clinical trial follow-up, the highest doses of olezarsen, plozasiran, and zodasiran lowered TG by 55.2%, 50.57%, and 51.2% of baseline levels. All three drugs decreased non-HDL-C and remnant cholesterol. Olezarsen and plozasiran lowered ApoC-III and increased HDL-C, whereas zodasiran reduced HDL-C. Zodasiran decreased LDL-C, whereas olezarsen and plozasiran had no effects on LDL-C. Plozasiran and zodasiran lowered apolipoprotein B, but not olezarsen.

CONCLUSION

The newer RNA interference (RNAi) therapies appear safe and have excellent TG-lowering efficacy in patients with HTG and MHL.

Olezarsen, a liver-directed APOC3 ASO therapy for hypertriglyceridemia

INTRODUCTION

Apolipoprotein (apo)C-III, a key regulator of plasma triglyceride (TG) levels, is a prime candidate for the treatment of hypertriglyceridemia (HTG), prevention of acute pancreatitis, and reduction of future atherosclerotic cardiovascular disease (ASCVD) events.

AREAS COVERED

We discuss the role of apoC-III as a therapeutic target for HTG, describe the pharmacodynamics, pharmacokinetics, and metabolism of olezarsen, as well as report on the findings of recent clinical trials with this liver-directed APOC3 antisense oligonucleotide (ASO).

EXPERT OPINION

Olezarsen, a GalNac-conjugated ASO targeting apoC-III, can reduce TG levels by ~ 50% in patients with extreme HTG due to familial chylomicronemia syndrome, as well as in patients with moderate HTG. Attention is now focused on whether olezarsen reduces ASCVD risk in patients with moderate and severe HTG. While olezarsen does cause elevations in liver enzymes, these changes are not clinically meaningful, and are not associated with thrombocytopenia, an issue with its predecessor, volanesorsen. The need for 4-weekly administration puts olezarsen at a disadvantage to competing injectables. Results from the CORE, CORE2, and ESSENCE phase III clinical trials in patients with severe HTG, expected in the second half of 2025, will help determine the requirement for a larger cardiovascular outcomes trial.

Hypertriglyceridemia Therapy: Past, Present and Future Perspectives

Hypertriglyceridemia therapy is essential for preventing cardiovascular diseases. Fibrates belong to an important class of lipid-lowering drugs useful for the management of dyslipidaemia. By acting on the peroxisome proliferator-activated receptor (PPAR)-α, these drugs lower serum triglyceride levels and raise high-density lipoprotein cholesterol. Fibrate monotherapy is associated with a risk of myopathy and this risk is enhanced when these agents are administered together with statins. However, whereas gemfibrozil can increase plasma concentrations of statins, fenofibrate has less influence on the pharmacokinetics of statins. Pemafibrate is a new PPAR-α-selective drug considered for therapy, and clinical trials are ongoing. Apart from this class of drugs, new therapies have emerged with different mechanisms of action to reduce triglycerides and the risk of cardiovascular diseases.

Expanding therapeutic options: overview of novel pharmacotherapies for dyslipidemia

INTRODUCTION

Dyslipidemia plays a crucial role in the development of atherosclerotic cardiovascular diseases.

AREAS COVERED

This article explores the emerging therapeutic targets for the treatment of dyslipidemia and provides novel insights into this field. Thus, it aims to contribute to the understanding and advancement of therapeutic options for managing dyslipidemia.

EXPERT OPINION

Optimizing the use of available first- and second-line lipid-lowering drugs allows us to adequately control low-density lipoprotein cholesterol (LDL-C) levels, even in statin-intolerant individuals and in patients at high and very high risk of developing cardiovascular diseases who must reach more aggressive LDL-C targets. The drugs under development will further improve our ability to manage the overall lipid-related cardiovascular disease risk and target other dyslipidemia biomarkers.

Etiology and emerging treatments for familial chylomicronemia syndrome

INTRODUCTION

Familial chylomicronemia syndrome (FCS) is a rare autosomal recessive condition. Effective treatment is important as patients are at risk for severe and potentially fatal acute pancreatitis. We review recent developments in pharmacologic treatment for FCS, namely biological inhibitors of apolipoprotein (apo) C-III and angiopoietin-like protein 3 (ANGPTL3).

AREAS COVERED

FCS follows a biallelic inheritance pattern in which an individual inherits two pathogenic loss-of-function alleles of one of the five causal genes - LPL (in 60-80% of patients), GPIHBP1, APOA5, APOC2, and LMF1 - leading to the absence of lipolytic activity. Patients present from childhood with severely elevated triglyceride (TG) levels >10 mmol/L. Most patients with severe hypertriglyceridemia do not have FCS. A strict low-fat diet is the current first-line treatment, and existing lipid-lowering therapies are minimally effective in FCS. Apo C-III inhibitors are emerging TG-lowering therapies shown to be efficacious and safe in clinical trials. ANGPTL3 inhibitors, another class of emerging TG-lowering therapies, have been found to require at least partial lipoprotein lipase activity to lower plasma TG in clinical trials. ANGPTL3 inhibitors reduce plasma TG in patients with multifactorial chylomicronemia but not in patients with FCS who completely lack lipoprotein lipase activity.

EXPERT OPINION

Apo C-III inhibitors currently in development are promising treatments for FCS.

Genetic variation in apolipoprotein A-V in hypertriglyceridemia

PURPOSE OF REVIEW

While biallelic rare APOA5 pathogenic loss-of-function (LOF) variants cause familial chylomicronemia syndrome, heterozygosity for such variants is associated with highly variable triglyceride phenotypes ranging from normal to severe hypertriglyceridemia, often in the same individual at different time points. Here we provide an updated overview of rare APOA5 variants in hypertriglyceridemia.

RECENT FINDINGS

Currently, most variants in APOA5 that are considered to be pathogenic according to guidelines of the American College of Medical Genetics and Genomics are those resulting in premature termination codons. There are minimal high quality functional data on the impact of most rare APOA5 missense variants; many are considered as variants of unknown or uncertain significance. Furthermore, particular common polymorphisms of APOA5 , such as p.Ser19Trp and p.Gly185Cys in Caucasian and Asian populations, respectively, are statistically overrepresented in hypertriglyceridemia cohorts and are sometimes misattributed as being causal for chylomicronemia, when they are merely risk alleles for hypertriglyceridemia.

SUMMARY

Both biallelic and monoallelic LOF variants in APOA5 are associated with severe hypertriglyceridemia, although the biochemical phenotype in the monoallelic state is highly variable and is often exacerbated by secondary factors. Currently, with few exceptions, the principal definitive mechanism for APOA5 pathogenicity is through premature truncation. The pathogenic mechanisms of most missense variants in APOA5 remain unclear and require additional functional experiments or family studies.

Apolipoprotein C3: form begets function

Increased circulating levels of apolipoprotein C3 (APOC3) predict cardiovascular disease (CVD) risk in humans, and APOC3 promotes atherosclerosis in mouse models. APOC3's mechanism of action is due in large part to its ability to slow the clearance of triglyceride-rich lipoproteins (TRLs) and their remnants when APOC3 is carried by these lipoproteins. However, different pools and forms of APOC3 exert distinct biological effects or associations with atherogenic processes. Thus, lipid-free APOC3 induces inflammasome activation in monocytes whereas lipid particle-bound APOC3 does not. APOC3-enriched LDL binds better to the vascular glycosaminoglycan biglycan than does LDL depleted of APOC3. Patterns of APOC3 glycoforms predict CVD risk differently. The function of APOC3 bound to HDL is largely unknown. There is still much to learn about the mechanisms of action of different forms and pools of APOC3 in atherosclerosis and CVD, and whether APOC3 inhibition would prevent CVD risk in patients on LDL-cholesterol lowering medications.

New Biological Therapies for Low-Density Lipoprotein Cholesterol

Depressed low-density lipoprotein cholesterol concentration protects against atherosclerotic cardiovascular disease. Natural hypocholesterolemia states can have a monogenic etiology, caused by pathogenic loss of function variants in the PCSK9, ANGPTL3, MTTP, or APOB genes. In this focused review, we discuss development and clinical use of several new therapeutics that inhibit these gene products to target elevated levels of low-density lipoprotein cholesterol. In particular, inhibitors of proprotein convertase subtilisin kexin type 9 (PCSK9) have notably affected clinical practice, followed recently by inhibition of angiopoietin-like 3 (ANGPTL3). Currently used in the clinic are alirocumab and evolocumab, two anti-PCSK9 monoclonal antibodies, inclisiran, a small interfering RNA that prevents PCSK9 translation, evinacumab, an anti-ANGPTL3 monoclonal antibody, and lomitapide, a small-molecule inhibitor of microsomal triglyceride transfer protein. Additional therapies are in preclinical or clinical trial stages of development. These consist of other monoclonal antibodies, antisense oligonucleotides, small-molecule inhibitors, mimetic peptides, adnectins, vaccines, and gene-editing therapies. Vaccines and gene-editing therapies in particular hold great potential to confer active long-term attenuation or provide single-treatment life-long knock-down of PCSK9 or ANGPTL3 activity. Biologic therapies inspired by monogenic hypocholesterolemia states are becoming valuable tools to help protect against atherosclerotic cardiovascular disease.

Updates in Small Interfering RNA for the Treatment of Dyslipidemias

PURPOSE OF REVIEW

Atherosclerotic cardiovascular disease (ASCVD) is still the leading cause of death worldwide. Despite excellent pharmacological approaches, clinical registries consistently show that many people with dyslipidemia do not achieve optimal management, and many of them are treated with low-intensity lipid-lowering therapies. Beyond the well-known association between low-density lipoprotein cholesterol (LDL-C) and cardiovascular prevention, the atherogenicity of lipoprotein(a) and the impact of triglyceride (TG)-rich lipoproteins cannot be overlooked. Within this landscape, the use of RNA-based therapies can help the treatment of difficult to target lipid disorders.

RECENT FINDINGS

The safety and efficacy of LDL-C lowering with the siRNA inclisiran has been documented in the open-label ORION-3 trial, with a follow-up of 4 years. While the outcome trial is pending, a pooled analysis of ORION-9, ORION-10, and ORION-11 has shown the potential of inclisiran to reduce composite major adverse cardiovascular events. Concerning lipoprotein(a), data of OCEAN(a)-DOSE trial with olpasiran show a dose-dependent drop in lipoprotein(a) levels with an optimal pharmacodynamic profile when administered every 12 weeks. Concerning TG lowering, although ARO-APOC3 and ARO-ANG3 are effective to lower apolipoprotein(apo)C-III and angiopoietin-like 3 (ANGPTL3) levels, these drugs are still in their infancy. In the era moving toward a personalized risk management, the use of siRNA represents a blossoming armamentarium to tackle dyslipidaemias for ASCVD risk reduction.

Updates in Drug Treatment of Severe Hypertriglyceridemia

PURPOSE OF REVIEW

To provide an insight into the new pharmacological options for the treatment of severe hypertriglyceridemia (sHTG).

RECENT FINDINGS

sHTG is difficult to treat. The majority of the traditional pharmacological agents available have limited success in both robustly decreasing triglyceride levels and/or in reducing the incidence of acute pancreatitis (AP), the most severe complication of sHTG. Therapeutic options with novel mechanisms of action have been developed, such as antisense oligonucleotides (ASO) and small interfering RNA (siRNA) targeting APOC3 and ANGPTL3. The review discusses also 2 abandoned drugs for sHTG treatment, evinacumab and vupanorsen. The ASO targeting APOC3, volanesorsen, is approved for use in patients with familial chylomicronemia syndrome (FCS) in Europe. Olezarsen, an N-acetylgalactosamine (GalNAc)-conjugated ASO with the same target, seems to have a better safety and efficacy profile. siRNA targeting APOC3 and ANGPTL3, namely ARO-APOC3 and ARO-ANG3, are also promising for the treatment of sHTG. However, the ultimate clinical goal of any sHTG treatment, the decrease in the risk of AP, has not been definitively achieved till now by any pharmacotherapy, either approved or in development.

Advances in Treatment of Dyslipidemia

Dyslipidemias have emerged as prevalent disorders among patients, posing significant risks for the development and progression of cardiovascular diseases. These conditions are characterized by elevated levels of total cholesterol (TC), triglycerides (TGs), and low-density lipoprotein cholesterol (LDL-C). This review delves into the current treatment approach, focusing on equalizing these parameters while enhancing the overall quality of life for patients. Through an extensive analysis of clinical trials, we identify disorders that necessitate alternative treatment strategies, notably familial hypercholesterolemia. The primary objective of this review is to consolidate existing information concerning drugs with the potential to revolutionize dyslipidemia management significantly. Among these promising pharmaceuticals, we highlight alirocumab, bempedoic acid, antisense oligonucleotides, angiopoietin-like protein inhibitors, apolipoprotein C-III (APOC3) inhibitors, lomitapide, and cholesterol ester transfer protein (CETP) inhibitors. Our review demonstrates the pivotal roles played by each of these drugs in targeting specific parameters of lipid metabolism. We outline the future landscape of dyslipidemia treatment, envisaging a more tailored and effective therapeutic approach to address this widespread medical concern.