Acute impact of apheresis on oxidized phospholipids in patients with familial hypercholesterolemia

Clinical practice recommendations on lipoprotein apheresis for children with homozygous familial hypercholesterolaemia: An expert consensus statement from ERKNet and ESPN

Homozygous familial hypercholesterolaemia is a life-threatening genetic condition, which causes extremely elevated LDL-C levels and atherosclerotic cardiovascular disease very early in life. It is vital to start effective lipid-lowering treatment from diagnosis onwards. Even with dietary and current multimodal pharmaceutical lipid-lowering therapies, LDL-C treatment goals cannot be achieved in many children. Lipoprotein apheresis is an extracorporeal lipid-lowering treatment, which is used for decades, lowering serum LDL-C levels by more than 70% directly after the treatment. Data on the use of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia mainly consists of case-reports and case-series, precluding strong evidence-based guidelines. We present a consensus statement on lipoprotein apheresis in children based on the current available evidence and opinions from experts in lipoprotein apheresis from over the world. It comprises practical statements regarding the indication, methods, treatment goals and follow-up of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia and on the role of lipoprotein(a) and liver transplantation.

Oxidized phospholipids in cardiovascular disease

Prolonged or excessive exposure to oxidized phospholipids (OxPLs) generates chronic inflammation. OxPLs are present in atherosclerotic lesions and can be detected in plasma on apolipoprotein B (apoB)-containing lipoproteins. When initially conceptualized, OxPL-apoB measurement in plasma was expected to reflect the concentration of minimally oxidized LDL, but, surprisingly, it correlated more strongly with plasma lipoprotein(a) (Lp(a)) levels. Indeed, experimental and clinical studies show that Lp(a) particles carry the largest fraction of OxPLs among apoB-containing lipoproteins. Plasma OxPL-apoB levels provide diagnostic information on the presence and extent of atherosclerosis and improve the prognostication of peripheral artery disease and first and recurrent myocardial infarction and stroke. The addition of OxPL-apoB measurements to traditional cardiovascular risk factors improves risk reclassification, particularly in patients in intermediate risk categories, for whom improving decision-making is most impactful. Moreover, plasma OxPL-apoB levels predict cardiovascular events with similar or greater accuracy than plasma Lp(a) levels, probably because this measurement reflects both the genetics of elevated Lp(a) levels and the generalized or localized oxidation that modifies apoB-containing lipoproteins and leads to inflammation. Plasma OxPL-apoB levels are reduced by Lp(a)-lowering therapy with antisense oligonucleotides and by lipoprotein apheresis, niacin therapy and bariatric surgery. In this Review, we discuss the role of role OxPLs in the pathophysiology of atherosclerosis and Lp(a) atherogenicity, and the use of OxPL-apoB measurement for improving prognosis, risk reclassification and therapeutic interventions.

Recommendations of the Experts of the Polish Cardiac Society (PCS) and the Polish Lipid Association (PoLA) on the diagnosis and management of elevated lipoprotein(a) levels

Lipoprotein(a) [Lp(a)] is made up of a low-density lipoprotein (LDL) particle and a specific apolipoprotein(a). The blood concentration of Lp(a) is approximately 90% genetically determined, and the main genetic factor determining Lp(a) levels is the size of the apo(a) isoform, which is determined by the number of KIV2 domain repeats. The size of the apo(a) isoform is inversely proportional to the blood concentration of Lp(a). Lp(a) is a strong and independent cardiovascular risk factor. Elevated Lp(a) levels ≥ 50 mg/dl (≥ 125 nmol/l) are estimated to occur in more than 1.5 billion people worldwide. However, determination of Lp(a) levels is performed far too rarely, including Poland, where, in fact, it is only since the 2021 guidelines of the Polish Lipid Association (PoLA) and five other scientific societies that Lp(a) measurements have begun to be performed. Determination of Lp(a) concentrations is not easy due to, among other things, the different sizes of the apo(a) isoforms; however, the currently available certified tests make it possible to distinguish between people with low and high cardiovascular risk with a high degree of precision. In 2022, the first guidelines for the management of patients with elevated lipoprotein(a) levels were published by the European Atherosclerosis Society (EAS) and the American Heart Association (AHA). The first Polish guidelines are the result of the work of experts from the two scientific societies and their aim is to provide clear, practical recommendations for the determination and management of elevated Lp(a) levels.

Clinical practice recommendations on lipoprotein apheresis for children with homozygous familial hypercholesterolemia: an expert consensus statement from ERKNet and ESPN

Homozygous familial hypercholesterolaemia is a life-threatening genetic condition, which causes extremely elevated LDL-C levels and atherosclerotic cardiovascular disease very early in life. It is vital to start effective lipid-lowering treatment from diagnosis onwards. Even with dietary and current multimodal pharmaceutical lipid-lowering therapies, LDL-C treatment goals cannot be achieved in many children. Lipoprotein apheresis is an extracorporeal lipid-lowering treatment, which is well established since three decades, lowering serum LDL-C levels by more than 70% per session. Data on the use of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia mainly consists of case-reports and case-series, precluding strong evidence-based guidelines. We present a consensus statement on lipoprotein apheresis in children based on the current available evidence and opinions from experts in lipoprotein apheresis from over the world. It comprises practical statements regarding the indication, methods, treatment targets and follow-up of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia and on the role of lipoprotein(a) and liver transplantation.

Lipoprotein(a) in clinical practice: A guide for the clinician

Cardiovascular disease (CVD) remains the leading cause of death worldwide. Serum lipoprotein(a) (Lp(a)) has been shown to be an independent and causative risk factor for atherosclerotic CVD and calcific aortic valvular disease. Lp(a) continues to be studied, with emerging insights into the epidemiology of CVD with respect to Lp(a), pathogenic mechanisms of Lp(a) and strategies to mitigate disease. There have been novel insights into genetic polymorphisms of the LPA gene, interactions between concomitant risk factors and Lp(a) based on real-world data, and metabolic pathway targets for Lp(a) reduction. This review highlights these recent advances in our understanding of Lp(a) and discusses management strategies as recommended by cardiovascular professional societies, emerging therapies for lowering Lp(a), and future directions in targeting Lp(a) to reduce CVD.

Recent lipoprotein(a) trials

PURPOSE OF REVIEW

Lipoprotein(a) (Lp(a)) is a genetically determined independent risk factor for cardiovascular disease and calcific aortic stenosis; thus, serum levels are minimally affected by conventional treatments for hypercholesterolemia and hypertriglyceridemia. New RNA therapies directly targeting Lp(a) have demonstrated efficacy in decreasing serum levels. Several recent trials have demonstrated efficacy and safety of these RNA therapeutics.

RECENT FINDINGS

Single-stranded antisense oligonucleotides (ASOs) and small interfering RNA (siRNA) are two classes of RNA-targeted therapeutics that specifically target the LPA gene, which encodes for apolipoprotein(a), a dominant and rate-limiting component in the hepatic synthesis of Lp(a) particle. Pelacarsen (ASO), olpasiran (siRNA) and SLN360 (siRNA) are novel drugs that have demonstrated efficacy in lowering Lp(a) levels and excellent safety profiles.

SUMMARY

Lp(a) is an independent risk factor for cardiovascular disease. RNA-directed therapies, pelacarsen, olpasiran and SLN360, have shown efficacy in dramatically lowering serum Lp(a) levels. Outcomes data will be the next frontier of Lp(a) trials.

Pharmacotherapy for children with elevated levels of lipoprotein(a): future directions

INTRODUCTION

Elevated lipoprotein(a) [Lp(a)] is an independent risk factor for atherosclerotic cardiovascular disease (ASCVD). With the advent of the antisense oligonucleotides (ASOs) and small interfering RNAs (siRNAs) targeted at LPA, the gene encoding apolipoprotein(a), that are highly effective for lowering Lp(a) levels, this risk factor might be managed in the near future. Given that Lp(a) levels are mostly genetically determined and once elevated, present from early age, we have evaluated future directions for the treatment of children with high Lp(a) levels.

AREAS COVERED

In the current review, we discuss different pharmacological treatments in clinical development and provide an in-depth overview of the effects of ASOs and siRNAs targeted at LPA.

EXPERT OPINION

Since high Lp(a) is an important risk factor for ASCVD and given the promising effects of both ASOs and siRNAs targeted at apo(a), there is an urgent need for well-designed prospective studies to assess the impact of elevated Lp(a) in childhood. If the Lp(a)-hypothesis is confirmed in adults, and also in children, the rationale might arise for treating children with high Lp(a) levels. However, we feel that this should be limited to children with the highest cardiovascular risk including familial hypercholesterolemia and potentially pediatric stroke.

Use of Lipoprotein(a) in clinical practice: A biomarker whose time has come. A scientific statement from the National Lipid Association

Lipoprotein(a) [Lp(a)] is a well-recognized, independent risk factor for atherosclerotic cardiovascular disease, with elevated levels estimated to be prevalent in 20% of the population. Observational and genetic evidence strongly support a causal relationship between high plasma concentrations of Lp(a) and increased risk of atherosclerotic cardiovascular disease-related events, such as myocardial infarction and stroke, and valvular aortic stenosis. In this scientific statement, we review an array of evidence-based considerations for testing of Lp(a) in clinical practice and the utilization of Lp(a) levels to inform treatment strategies in primary and secondary prevention.

Oxidized phospholipids and lipoprotein(a): An update

Over the past few years, there has been an undiminished interest in lipoprotein(a) [Lp(a)] and oxidized phospholipids (OxPLs), mainly carried on this lipoprotein. Elevated Lp(a) has been established as an independent causal risk factor for cardiovascular disease. OxPLs play an important role in atherosclerosis. The main questions that remain to be answered, however, is to what extent OxPLs contribute to the atherogenicity of Lp(a), what effect hypolipidaemic medications may have on their levels and the potential clinical benefit of their reduction. This narrative review aimed to summarize currently available data on OxPLs and cardiovascular risk, as well as the effect of established and emerging hypolipidaemic medications on Lp(a)-OxPLs.

Lipoprotein(a), venous thromboembolism and COVID-19: A pilot study

Background and aims

Thrombosis is a major driver of adverse outcome and mortality in patients with Coronavirus disease 2019 (COVID-19). Hypercoagulability may be related to the cytokine storm associated with COVID-19, which is mainly driven by interleukin (IL)-6. Plasma lipoprotein(a) [Lp(a)] levels increase following IL-6 upregulation and Lp(a) has anti-fibrinolytic properties. This study investigated whether Lp(a) elevation may contribute to the pro-thrombotic state hallmarking COVID-19 patients.

Methods

Lp(a), IL-6 and C-reactive protein (CRP) levels were measured in 219 hospitalized patients with COVID-19 and analyzed with linear mixed effects model. The baseline biomarkers and increases during admission were related to venous thromboembolism (VTE) incidence and clinical outcomes in a Kaplan-Meier and logistic regression analysis.

Results

Lp(a) levels increased significantly by a mean of 16.9 mg/dl in patients with COVID-19 during the first 21 days after admission. Serial Lp(a) measurements were available in 146 patients. In the top tertile of Lp(a) increase, 56.2% of COVID-19 patients experienced a VTE event compared to 18.4% in the lowest tertile (RR 3.06, 95% CI 1.61–5.81; p < 0.001). This association remained significant after adjusting for age, sex, IL-6 and CRP increase and number of measurements. Increases in IL-6 and CRP were not associated with VTE. Increase in Lp(a) was strongly correlated with increase in IL-6 (r = 0.44, 95% CI 0.30–0.56, p < 0.001).

Conclusions

Increases in Lp(a) levels during the acute phase of COVID-19 were strongly associated with VTE incidence. The acute increase in anti-fibrinolytic Lp(a) may tilt the balance to VTE in patients hospitalized for COVID-19.

Lipoprotein (a) as a treatment target for cardiovascular disease prevention and related therapeutic strategies: a critical overview

Advances in several fields of cardiovascular (CV) medicine have produced new treatments (e.g. to treat dyslipidaemia) that have proven efficacy in terms of reducing deaths and providing a better quality of life. However, the burden of CV disease (CVD) remains high. Thus, there is a need to search for new treatment targets. Lipoprotein (a) [Lp(a)] has emerged as a potential novel target since there is evidence that it contributes to CVD events. In this narrative review, we present the current evidence of the potential causal relationship between Lp(a) and CVD and discuss the likely magnitude of Lp(a) lowering required to produce a clinical benefit. We also consider current and investigational treatments targeting Lp(a), along with the potential cost of these interventions.

Effect of bariatric surgery on plasma levels of oxidised phospholipids, biomarkers of oxidised LDL and lipoprotein(a)

BACKGROUND

Obesity is associated with adverse cardiovascular outcomes and this is improved following bariatric surgery. Oxidised phospholipids (OxPL) are thought to reflect the pro-inflammatory effects of lipoprotein(a) [Lp(a)], and both are independent predictors of cardiovascular disease.

OBJECTIVE

Our study sought to determine the impact of bariatric surgery on OxPL, biomarkers of oxidised LDL (OxLDL) and Lp(a).

METHODS

This is a prospective, observational study of 59 patients with severe obesity undergoing bariatric surgery. Blood samples were obtained prior to surgery and at 6 and 12 months after. Sixteen patients attending the tertiary medical weight management clinic at the same centre were also recruited for comparison. Lipid and metabolic blood parameters, OxLDL, OxPL on apolipoprotein B-100 (OxPL-apoB), IgG and IgM autoantibodies to MDA-LDL, IgG and IgM apoB-immune complexes and Lp(a) were measured.

RESULTS

Reduction in body mass index (BMI) was significant following bariatric surgery, from median 48 kg/m2 at baseline to 37 kg/m2 at 6 months and 33 kg/m2 at 12 months. OxPL-apoB levels decreased significantly at 12 months following surgery [5.0 (3.2-7.4) to 3.8 (3.0-5.5) nM, p = 0.001], while contrastingly, Lp(a) increased significantly [10.2 (3.8-31.9) to 16.9 (4.9-38.6) mg/dl, p = 0.002]. There were significant post-surgical decreases in IgG and IgM biomarkers, particularly at 12 months, while OxLDL remained unchanged.

CONCLUSIONS

Bariatric surgery results in a significant increase in Lp(a) but reductions in OxPL-apoB and other biomarkers of oxidised lipoproteins, suggesting increased synthetic capacity and reduced oxidative stress. These biomarkers might be clinically useful to monitor physiological effects of weight loss interventions.

Desialylation of platelet surface glycans enhances platelet adhesion to adsorbent polymers for lipoprotein apheresis

Background:

Lipoprotein apheresis is an important therapeutic option in homozygous familial hypercholesterolemia, progressive atherosclerosis, or when depletion of lipoprotein(a) is indicated. It is generally regarded as safe, but drops in platelet counts as well as sporadic episodes of thrombocytopenia have been reported. We assessed the influence of platelet desialylation, which may be induced by endogenous or pathogen-derived neuraminidases, on platelet adhesion to polyacrylate-based adsorbents for whole blood lipoprotein apheresis.

Methods:

Medical grade platelet concentrates were incubated with neuraminidase in vitro and were circulated over adsorbent columns downscaled from clinical application.

Results:

Cleavage of terminal sialic residues resulted in platelet activation with significantly elevated expression of platelet factor 4 (PF4) and in enhanced platelet adhesion to the adsorbent, accompanied by a pronounced drop in platelet counts in the column flow-through.

Conclusion:

Alterations in endogenous neuraminidase activity or exogenous (pathogen-derived) neuraminidase may trigger enhanced platelet adhesion in whole blood lipoprotein apheresis.

The Impact of Lipoprotein Apheresis on Oxidative Stress Biomarkers and High-Density Lipoprotein Subfractions

Lipoprotein apheresis (LA) treatment results in a substantial reduction of low-density lipoprotein- (LDL-) cholesterol and lipoprotein(a) concentrations, which consequently decreases the rate of cardiovascular events. The additional benefit of LA may be associated with its impact on the composition and quality of high-density lipoprotein (HDL) particles, inflammation, and oxidative stress condition. To verify the effects of LA procedure, the current study is aimed at analyzing the effect of a single apheresis procedure with direct hemadsorption (DALI) and cascade filtration (MONET) on oxidative stress markers and HDL-related parameters. The study included eleven patients with familial hypercholesterolemia and hyperlipoproteinemia(a) treated with regular LA (DALI or MONET). We investigated the pre- and postapheresis concentration of the lipid-related oxidative stress markers 8-isoPGF2, oxLDL, TBARS, and PON-1. We also tracked potential changes in the main HDL apolipoproteins (ApoA-I, ApoA-II) and cholesterol contained in HDL subfractions. A single session of LA with DALI or MONET techniques resulted in a similar reduction of lipid-related oxidative stress markers. Concentrations of 8-isoPGF2 and TBARS were reduced by ~60% and ~30%, respectively. LA resulted in a 67% decrease in oxLDL levels along with a ~19% reduction in the oxLDL/ApoB ratio. Concentrations of HDL cholesterol, ApoA-I, ApoA-II, and PON-1 activity were also reduced by LA sessions, with more noticeable effects seen in the MONET technique. The quantitative proportions between HDL₂ and HDL₃ cholesterol did not change significantly by both methods. In conclusion, LA treatment with MONET or DALI system has a small nonselective effect on lowering HDL particles without any changes in the protein composition of these particles. Significant reduction in the level of oxidative stress parameters and less oxidation of LDL particles may provide an additional benefit of LA therapy.

Lipoprotein(a) the Insurgent: A New Insight into the Structure, Function, Metabolism, Pathogenicity, and Medications Affecting Lipoprotein(a) Molecule

Lipoprotein(a) [Lp(a)], aka "Lp little a", was discovered in the 1960s in the lab of the Norwegian physician Kåre Berg. Since then, we have greatly improved our knowledge of lipids and cardiovascular disease (CVD). Lp(a) is an enigmatic class of lipoprotein that is exclusively formed in the liver and comprises two main components, a single copy of apolipoprotein (apo) B-100 (apo-B100) tethered to a single copy of a protein denoted as apolipoprotein(a) apo(a). Plasma levels of Lp(a) increase soon after birth to a steady concentration within a few months of life. In adults, Lp(a) levels range widely from <2 to 2500 mg/L. Evidence that elevated Lp(a) levels >300 mg/L contribute to CVD is significant. The improvement of isoform-independent assays, together with the insight from epidemiologic studies, meta-analyses, genome-wide association studies, and Mendelian randomization studies, has established Lp(a) as the single most common independent genetically inherited causal risk factor for CVD. This breakthrough elevated Lp(a) from a biomarker of atherosclerotic risk to a target of therapy. With the emergence of promising second-generation antisense therapy, we hope that we can answer the question of whether Lp(a) is ready for prime-time clinic use. In this review, we present an update on the metabolism, pathophysiology, and current/future medical interventions for high levels of Lp(a).

Familial hypercholesterolemia and elevated lipoprotein(a): double heritable risk and new therapeutic opportunities

There is compelling evidence that the elevated plasma lipoprotein(a) [Lp(a)] levels increase the risk of atherosclerotic cardiovascular disease (ASCVD) in the general population. Like low-density lipoprotein (LDL) particles, Lp(a) particles contain cholesterol and promote atherosclerosis. In addition, Lp(a) particles contain strongly proinflammatory oxidized phospholipids and a unique apoprotein, apo(a), which promotes the growth of an arterial thrombus. At least one in 250 individuals worldwide suffer from the heterozygous form of familial hypercholesterolemia (HeFH), a condition in which LDL-cholesterol (LDL-C) is significantly elevated since birth. FH-causing mutations in the LDL receptor gene demonstrate a clear gene-dosage effect on Lp(a) plasma concentrations and elevated Lp(a) levels are present in 30-50% of patients with HeFH. The cumulative burden of two genetically determined pro-atherogenic lipoproteins, LDL and Lp(a), is a potent driver of ASCVD in HeFH patients. Statins are the cornerstone of treatment of HeFH, but they do not lower the plasma concentrations of Lp(a). Emerging therapies effectively lower Lp(a) by as much as 90% using RNA-based approaches that target the transcriptional product of the LPA gene. We are now approaching the dawn of an era, in which permanent and significant lowering of the high cholesterol burden of HeFH patients can be achieved. If outcome trials of novel Lp(a)-lowering therapies prove to be safe and cost-effective, they will provide additional risk reduction needed to effectively treat HeFH and potentially lower the CVD risk in these high-risk patients even more than currently achieved with LDL-C lowering alone.

Lipoprotein apheresis is an optimal therapeutic option to reduce increased Lp(a) levels

BACKGROUND

Lipoprotein(a) (Lp(a)) is a genetic risk factor for cardiovascular disease (CVD) and is associated with the induction and sustaining of atherosclerotic cardiovascular diseases (ASCVD). Since 2008 Lp(a) along with progressive CVD has been approved as an indication for regular lipoprotein apheresis (LA) in Germany. The German Lipoprotein Apheresis Registry (GLAR) has been initiated to provide statistical evidence for the assessment of extracorporeal procedures to treat dyslipidemia for both LDL-cholesterol (LDL-C) and Lp(a). The GLAR now allows prospective investigations over a 5-year period about annual incidence rates of cardiovascular events. Here Lp(a) patients (LDL-C < 100 mg/dl; Lp(a) > 60 mg/dl or >120 nmol/l) showed the same reduction of major coronary (83%) and non-coronary events (63%) as had been formerly shown in the Pro(a)LiFe study. However, Lp(a) is not only an apolipoprotein(a) (apo(a)) and LDL-C containing particle, which is covalently bound to a LDL-C core by a disulphide bridge. The composition of this particle, inter alia containing oxidized phospholipids, gives pro-atherosclerotic, pro-inflammatory, and pro-thrombotic properties, inducing atherosclerotic processes mainly in the arterial wall. However, recent investigations have shown that a reduction of inflammatory settings without LDL-C or Lp(a) reduction may reduce ASCVD events. Lipoprotein apheresis (LA) could not only reduce LDL-C and Lp(a) in parallel, but also different inflammatory and coagulation parameters. In summary lipoprotein apheresis is not only anti-atherosclerotic, but also anti-inflammatory and anti-thrombotic and therefore an ideal treatment option with respect to the shown reduction of major adverse coronary events (MACE) and major adverse non-coronary events (MANCE) by reducing Lp(a) levels.

Potent reduction of plasma lipoprotein (a) with an antisense oligonucleotide in human subjects does not affect ex vivo fibrinolysis

It is postulated that lipoprotein (a) [Lp(a)] inhibits fibrinolysis, but this hypothesis has not been tested in humans due to the lack of specific Lp(a) lowering agents. Patients with elevated Lp(a) were randomized to antisense oligonucleotide [IONIS-APO(a)_Rx] directed to apo(a) (n = 7) or placebo (n = 10). Ex vivo plasma lysis times and antigen concentrations of plasminogen, factor XI, plasminogen activator inhibitor 1, thrombin activatable fibrinolysis inhibitor, and fibrinogen at baseline, day 85/92/99 (peak drug effect), and day 190 (3 months off drug) were measured. The mean ± SD baseline Lp(a) levels were 477.3 ± 55.9 nmol/l in IONIS-APO(a)_Rx and 362.1 ± 89.9 nmol/l in placebo. The mean± SD percentage change in Lp(a) for IONIS-APO(a)_Rx was -69.3 ± 12.2% versus -5.4 ± 6.9% placebo (P < 0.0010) at day 85/92/99 and -15.6 ± 8.9% versus 3.2 ± 12.2% (P = 0.003) at day 190. Clot lysis times and coagulation/fibrinolysis-related biomarkers showed no significant differences between IONIS-APO(a)_Rx and placebo at all time points. Clot lysis times were not affected by exogenously added Lp(a) at concentrations up to 200 nmol/l to plasma with very low (12.5 nmol/l) Lp(a) levels, whereas recombinant apo(a) had a potent antifibrinolytic effect. In conclusion, potent reductions of Lp(a) in patients with highly elevated Lp(a) levels do not affect ex vivo measures of fibrinolysis; the relevance of any putative antifibrinolytic effects of Lp(a) in vivo needs further study.

A monoclonal antibody to assess oxidized cholesteryl esters associated with apoAI and apoB-100 lipoproteins in human plasma

Atherosclerosis is associated with increased lipid peroxidation, leading to generation of multiple oxidation-specific epitopes (OSEs), contributing to the pathogenesis of atherosclerosis and its clinical manifestation. Oxidized cholesteryl esters (OxCEs) are a major class of OSEs found in human plasma and atherosclerotic tissue. To evaluate OxCEs as a candidate biomarker, we generated a novel mouse monoclonal Ab (mAb) specific to an OxCE modification of proteins. The mAb AG23 (IgG1) was raised in C57BL6 mice immunized with OxCE-modified keyhole limpet hemocyanin, and hybridomas were screened against OxCE-modified BSA. This method ensures mAb specificity to the OxCE modification, independent of a carrier protein. AG23 specifically stained human carotid artery atherosclerotic lesions. An ELISA method, with AG23 as a capture and either anti-apoAI or anti-apoB-100 as the detection Abs, was developed to assay apoAI and apoB-100 lipoproteins that have one or more OxCE epitopes. OxCE-apoA or OxCE-apoB did not correlate with the well-established oxidized phospholipid-apoB biomarker. In a cohort of subjects treated with atorvastatin, OxCE-apoA was significantly lower than in the placebo group, independent of the apoAI levels. These results suggest the potential diagnostic utility of a new biomarker assay to measure OxCE-modified lipoproteins in patients with CVD.

Lipoprotein(a) and oxidized phospholipids in calcific aortic valve stenosis

PURPOSE OF REVIEW

As the incidence of calcific aortic valve stenosis increases with the aging of the population, improved understanding and novel therapies to reduce its progression and need for aortic valve replacement are urgently needed.

RECENT FINDINGS

Lipoprotein(a) is the only monogenetic risk factor for calcific aortic stenosis. Elevated levels are a strong, causal, independent risk factor, as demonstrated in epidemiological, genome-wide association studies and Mendelian randomization studies. Lipoprotein(a) is the major lipoprotein carrier of oxidized phospholipids, which are proinflammatory and promote calcification of vascular cells, two key pathophysiological drivers of aortic stenosis. Elevated plasma lipoprotein(a) and oxidized phospholipids predict progression of pre-existing aortic stenosis and need for aortic valve replacement. The failure of statin trials in pre-existing aortic stenosis may be partially due to an increase in lipoprotein(a) and oxidized phospholipid levels caused by statins. Antisense oligonucleotides targeted to apo(a) are in Phase 2 clinical development and shown to lower both lipoprotein(a) and oxidized phospholipids.

SUMMARY

Lipoprotein(a) and oxidized phospholipids are key therapeutic targets in calcific aortic stenosis. Strategies aimed at potent lipoprotein(a) lowering to normalize levels and/or to suppress the proinflammatory effects of oxidized phospholipids may prevent progression of this disease.

Lipoprotein(a)-hyperlipoproteinemia as cause of chronic spinal cord ischemia resulting in progressive myelopathy - successful treatment with lipoprotein apheresis

High concentrations of lipoprotein(a) (Lp(a)) represent an important independent and causal risk factor associated with adverse outcome in atherosclerotic cardiovascular disease (CVD). Effective Lp(a) lowering drug treatment is not available. Lipoprotein apheresis (LA) has been proven to prevent cardiovascular events in patients with Lp(a)-hyperlipoproteinemia (Lp(a)-HLP) and progressive CVD. Here we present the course of a male patient with established peripheral arterial occlusive disease (PAOD) at the early age of 41 and coronary artery disease (CAD), who during follow-up developed over 2 years a progressive syndrome of cerebellar and spinal cord deficits against the background of multifactorial cardiovascular risk including positive family history of CVD. Spastic tetraplegia and dependency on wheel chair and nursing care represented the nadir of neurological deficits. All conventional risk factors including LDL-cholesterol had already been treated and after exclusion of other causes, genetically determined Lp(a)-HLP was considered as the major underlying etiologic factor of ischemic vascular disease in this patient including spinal cord ischemia with vascular myelopathy. Treatment with an intensive regimen of chronic LA over 4.5 years now was successful to stabilize PAOD and CAD and led to very impressive neurologic and overall physical rehabilitation and improvement of quality of life.

Measurement of Lp(a) concentration must be recommended to assess individual cardiovascular risk. Extracorporeal clearance of Lp(a) by LA should be considered as treatment option for select patients with progressive Lp(a)-associated ischemic syndromes.

The impact of citrate concentration on adhesion of platelets and leukocytes to adsorbents in whole blood lipoprotein apheresis

Lipoprotein apheresis is applied to deplete low density lipoprotein and other apolipoprotein B containing lipoproteins in patients with severe familial hypercholesterolemia, hypertriglyceridemia associated pancreatitis, or lipoprotein (a)-hyperlipoproteinemia. Anticoagulation of the extracorporeal circuit may influence cellular activation, as evidenced by a reduction of inflammatory parameters during regional citrate anticoagulation with acid citrate dextrose A (ACD-A) commonly used in whole blood lipid apheresis. While the citrate concentration in the extracorporeal circuit has to ensure efficient anticoagulation, citrate infusion into the patient should be limited to avoid citrate overload. We assessed the influence of citrate concentration on cellular activation during in vitro circulation of whole blood containing 2.8 mM citrate (ACD-A 1:40), 5.6 mM citrate (ACD-A 1:20), or 13 mM citrate over polyacrylate-based adsorbents for lipoprotein apheresis. We found increased platelet adhesion for anticoagulation with 2.8 mM citrate as compared to 5.6 or 13 mM citrate, as shown by cell counting and confirmed by scanning electron microscopy of adsorbent beads as well as by elevated levels of platelet activation markers and of platelet-derived microvesicles. Leukocytes showed an equivalent adhesion pattern, while red blood cells remained unaffected at all citrate concentrations. Passage of blood over two consecutive columns resulted in enhanced platelet adhesion to the second column, presumably due to upstream preactivation. In conclusion, citrate influences activation and adhesion of platelets and leukocytes in a concentration-dependent manner, and ACD-A 1:20, equivalent to a citrate concentration of 5.6 mM in whole blood, ensures minimal cellular activation during passage of whole blood over polyacrylate-based adsorbents.

Antisense oligonucleotides targeting apolipoprotein(a) in people with raised lipoprotein(a): two randomised, double-blind, placebo-controlled, dose-ranging trials

BACKGROUND

Elevated lipoprotein(a) (Lp[a]) is a highly prevalent (around 20% of people) genetic risk factor for cardiovascular disease and calcific aortic valve stenosis, but no approved specific therapy exists to substantially lower Lp(a) concentrations. We aimed to assess the efficacy, safety, and tolerability of two unique antisense oligonucleotides designed to lower Lp(a) concentrations.

METHODS

We did two randomised, double-blind, placebo-controlled trials. In a phase 2 trial (done in 13 study centres in Canada, the Netherlands, Germany, Denmark, and the UK), we assessed the effect of IONIS-APO(a)_Rx, an oligonucleotide targeting apolipoprotein(a). Participants with elevated Lp(a) concentrations (125-437 nmol/L in cohort A; ≥438 nmol/L in cohort B) were randomly assigned (in a 1:1 ratio in cohort A and in a 4:1 ratio in cohort B) with an interactive response system to escalating-dose subcutaneous IONIS-APO(a)_Rx (100 mg, 200 mg, and then 300 mg, once a week for 4 weeks each) or injections of saline placebo, once a week, for 12 weeks. Primary endpoints were mean percentage change in fasting plasma Lp(a) concentration at day 85 or 99 in the per-protocol population (participants who received more than six doses of study drug) and safety and tolerability in the safety population. In a phase 1/2a first-in-man trial, we assessed the effect of IONIS-APO(a)-L_Rx, a ligand-conjugated antisense oligonucleotide designed to be highly and selectively taken up by hepatocytes, at the BioPharma Services phase 1 unit (Toronto, ON, Canada). Healthy volunteers (Lp[a] ≥75 nmol/L) were randomly assigned to receive a single dose of 10-120 mg IONIS-APO(a)L_Rx subcutaneously in an ascending-dose design or placebo (in a 3:1 ratio; single-ascending-dose phase), or multiple doses of 10 mg, 20 mg, or 40 mg IONIS-APO(a)L_Rx subcutaneously in an ascending-dose design or placebo (in an 8:2 ratio) at day 1, 3, 5, 8, 15, and 22 (multiple-ascending-dose phase). Primary endpoints were mean percentage change in fasting plasma Lp(a) concentration, safety, and tolerability at day 30 in the single-ascending-dose phase and day 36 in the multiple-ascending-dose phase in participants who were randomised and received at least one dose of study drug. In both trials, the randomised allocation sequence was generated by Ionis Biometrics or external vendor with a permuted-block randomisation method. Participants, investigators, sponsor personnel, and clinical research organisation staff who analysed the data were all masked to the treatment assignments. Both trials are registered with ClinicalTrials.gov, numbers NCT02160899 and NCT02414594.

FINDINGS

From June 25, 2014, to Nov 18, 2015, we enrolled 64 participants to the phase 2 trial (51 in cohort A and 13 in cohort B). 35 were randomly assigned to IONIS-APO(a)_Rx and 29 to placebo. At day 85/99, participants assigned to IONIS-APO(a)_Rx had mean Lp(a) reductions of 66·8% (SD 20·6) in cohort A and 71·6% (13·0) in cohort B (both p<0·0001 vs pooled placebo). From April 15, 2015, to Jan 11, 2016, we enrolled 58 healthy volunteers to the phase 1/2a trial of IONIS-APO(a)-L_Rx. Of 28 participants in the single-ascending-dose phase, three were randomly assigned to 10 mg, three to 20 mg, three to 40 mg, six to 80 mg, six to 120 mg, and seven to placebo. Of 30 participants in the multiple-ascending-dose phase, eight were randomly assigned to 10 mg, eight to 20 mg, eight to 40 mg, and six to placebo. Significant dose-dependent reductions in mean Lp(a) concentrations were noted in all single-dose IONIS-APO(a)-L_Rx groups at day 30. In the multidose groups, IONIS-APO(a)-L_Rx resulted in mean reductions in Lp(a) of 66% (SD 21·8) in the 10 mg group, 80% (SD 13·7%) in the 20 mg group, and 92% (6·5) in the 40 mg group (p=0·0007 for all vs placebo) at day 36. Both antisense oligonucleotides were safe. There were two serious adverse events (myocardial infarctions) in the IONIS-APO(a)_Rx phase 2 trial, one in the IONIS-APO(a)_Rx and one in the placebo group, but neither were thought to be treatment related. 12% of injections with IONIS-APO(a)_Rx were associated with injection-site reactions. IONIS-APO(a)-L_Rx was associated with no injection-site reactions.

INTERPRETATION

IONIS-APO(a)-L_Rx is a novel, tolerable, potent therapy to reduce Lp(a) concentrations. IONIS-APO(a)-L_Rx might mitigate Lp(a)-mediated cardiovascular risk and is being developed for patients with elevated Lp(a) concentrations with existing cardiovascular disease or calcific aortic valve stenosis.

FUNDING

Ionis Pharmaceuticals.

Lipoprotein apheresis in the management of severe hypercholesterolemia and of elevation of lipoprotein(a): current perspectives and patient selection

This review reports the current situation with respect to therapeutic options (lifestyle and drugs) reducing the concentrations of atherogenic low-density lipoprotein cholesterol (LDL-C) and lipoprotein(a) (Lp[a]). Three lipoprotein apheresis (LA) principles have been realized: precipitation, filtration, and adsorption. Available LA methods are herein described in detail - major components, pumps, extracorporeal volume, treated volume, and anticoagulation. General features of all LA methods as well as pleotropic effects are elaborated. Indications for LA therapy are quoted: homozygous familial hypercholesterolemia (HCH), severe HCH, and isolated elevation of Lp(a) and progress of atherosclerotic disease. A major focus is on the evidence of the effect of LA on cardiovascular outcome data, and the most important publications are cited in this context. The best studies have been performed in patients with elevated Lp(a) in whom cardiovascular events were reduced by more than 80%. Major adverse effects and contraindications are listed. The impact of an LA therapy on patient quality of life and the requirements they have to fulfill are also highlighted. Finally, the future role of LA in treating high-risk patients with high LDL-C and/or high Lp(a) is discussed. It is probable that the significance of LA for treating patients with elevated LDL-C will decrease (with the exception of homozygous familial HCH) due to the application of PCSK9 inhibitors. The antisense oligonucleotide against apolipoprotein(a) could replace LA in patients with high Lp(a), provided positive outcome data are generated.

Lipoprotein(a)-cholesterol levels estimated by vertical auto profile correlate poorly with Lp(a) mass in hyperlipidemic subjects: Implications for clinical practice interpretation of Lp(a)-mediated risk

BACKGROUND

Lipoprotein(a) [Lp(a)] is generally measured as total mass of the entire particle or as apolipoprotein(a) particle number.

OBJECTIVE

The cholesterol content of Lp(a) [Lp(a)-C)] can be estimated by the vertical auto profile (VAP) method. We assessed whether this is an accurate surrogate measurement of Lp(a) mass.

METHODS

VAP-Lp(a)-C and VAP-high density lipoprotein cholesterol (HDL-C) estimated by the VAP technique, Lp(a) mass, oxidized phospholipids on apolipoprotein B-100 (OxPL-apoB) that primarily reflect OxPL on Lp(a), and HDL-C measured by enzymatic methods were measured in 552 hypercholesterolemic patients at baseline and 24 weeks after therapy with niacin monotherapy (N = 118), ezetimibe/simvastatin monotherapy (n = 155), or ezetimibe/simvastatin (10/20 mg) + niacin (to 2 g) (N = 279) in a randomized, double-blind trial.

RESULTS

VAP-Lp(a)-C correlated only modestly with Lp(a) mass at baseline (r = 0.56, P < .001) and 24 weeks (r = 0.56, P < .001), explaining only 31% of the association. VAP-Lp(a)-C correlated with HDL-C at baseline (r = 0.34, P < .001) and 24 weeks (r = 0.30, P < .001) and with VAP-HDL-C at baseline (r = 39, P < .001) and 24 weeks (r = 0.33, P < .001). In contrast, Lp(a) mass did not correlate with HDL-C at baseline (r = 0.06, P = .12) and 24 weeks (r = -0.01 P = .91). Lp(a) mass correlated strongly with oxidized phospholipids on apolipoprotein B-100 at baseline (r = 0.81, P < .001) and 24 weeks (r = 0.79, P < .001). VAP-Lp(a)-C levels increased linearly with HDL-C and VAP-HDL-C quartiles (P < .001 for both) but Lp(a) mass did not. Quantitating the percent of cholesterol present on Lp(a) by dividing VAP-Lp(a)-C by Lp(a) mass revealed that 25% of patients had a percentage >100, which is not possible.

CONCLUSIONS

VAP-Lp(a)-C is a poor estimate for Lp(a) mass and likely reflects the content of HDL-C in the overlapping density spectrum of Lp(a) and HDL. These data suggest that patients with prior VAP-Lp(a)-C measurements may have misclassification of Lp(a)-related risk.

Lipoprotein Apheresis for Lipoprotein(a)-Associated Cardiovascular Disease

Objective—

Lipoprotein(a)-hyperlipoproteinemia (Lp(a)-HLP) along with progressive cardiovascular disease has been approved as indication for regular lipoprotein apheresis (LA) in Germany since 2008. We aimed to study the long-term preventive effect of LA and to assess hypothetical clinical correlations of apolipoprotein(a) (apo(a)) by analyzing genotypes and phenotypes.

Approach and Results—

This prospective observational multicenter study included 170 patients with Lp(a)-HLP and progressive cardiovascular disease (48.9 years median age at diagnosis) despite other cardiovascular risk factors, including low-density lipoprotein cholesterol had maximally been treated (mean baseline low-density lipoprotein cholesterol: measured, 2.56 mmol/L [98.9 mg/dL] and corrected, 1.72 mmol/L [66.3 mg/dL]). Patients were prospectively investigated during a 5-year period about annual incidence rates of cardiovascular events. In addition, apo(a) isoforms and polymorphisms at the apo(a) gene ( LPA ) were characterized. One hundred fifty-four patients (90.6%) completed 5 years of follow-up. Mean Lp(a) concentration before commencing regular LA was 108.1 mg/dL. This was reduced by a single LA treatment by 68.1% on average. Significant decline of the mean annual cardiovascular event rate was observed from 0.58±0.53 2 years before regular LA to 0.11±0.15 thereafter ( P <0.0001); 95.3% of patients expressed at least 1 small apo(a) isoform. Small apo(a) isoform (35.2%) carrying phenotypes were not tagged by single-nucleotide polymorphisms rs10455872 or rs3798220.

Conclusions—

Results of 5 years of prospective follow-up confirm that LA has a lasting effect on prevention of cardiovascular events in patients with Lp(a)-HLP. Patients clinically selected by progressive cardiovascular disease were characterized by a highly frequent expression of small apo(a) isoforms. Only Lp(a) concentration seemed to comprehensively reflect Lp(a)-associated cardiovascular risk, however.

The re-emergence of lipoprotein(a) in a broader clinical arena

Lipoprotein(a) [Lp(a)] is a genetic, independent and likely causal risk factor for cardiovascular disease (CVD) and calcific aortic valve stenosis (CAVS). Lp(a) levels are primarily genetically determined and tend to fluctuate only mildly around a pre-determined level. In primary care settings, one Lp(a) measurement can reclassify up to 40% of patients in intermediate risk score categories. In secondary care settings, recent data from the JUPITER and AIM-HIGH trials demonstrate that elevated Lp(a) remains part of the "residual risk" despite achievement of low-density lipoprotein cholesterol levels <70 mg/dL. Recent reports suggest that statins can increase Lp(a) levels, potentially further contributing to this residual risk. Current therapies to lower Lp(a) are limited to niacin, mipomersen and proprotein convertase subtilisin kexin-type 9 inhibitors, but these drugs are limited by weak efficacy and not specifically approved for Lp(a) lowering. Emerging therapies to lower Lp(a) may shed new light into the potential clinical benefit of lowering Lp(a) in CVD and CAVS.

Long-term mipomersen treatment is associated with a reduction in cardiovascular events in patients with familial hypercholesterolemia

BACKGROUND

Familial hypercholesterolemia (FH) is characterized by severely elevated LDL-cholesterol and up to a 20-fold increase in premature cardiovascular disease (CVD).

OBJECTIVE

Mipomersen has been shown to lower the levels of these atherogenic lipoproteins, but whether it lowers major adverse cardiac events (MACEs) has not been addressed.

METHODS

This post hoc analysis of prospectively collected data of three randomized trials and an open-label extension phase included patients that were exposed to ≥12 months of mipomersen. MACE rates that occurred during 24 months before randomization in the mipomersen group were compared to MACE rates after initiation of mipomersen. Data from the trials included in this report are registered in Clinicaltrials.gov (NCT00607373, NCT00706849, NCT00794664, NCT00694109). The occurrence of MACE events, defined as cardiovascular death, nonfatal acute myocardial infarction, hospitalization for unstable angina, coronary revascularization and nonfatal ischemic stroke, was obtained from medical history data pre-treatment and adjudicated by an independent adjudication committee for events occurring post-treatment with mipomersen.

RESULTS

MACEs were identified in 61.5% of patients (64 patients with 146 events [39 myocardial infarctions, 99 coronary revascularizations, 5 unstable angina episodes, 3 ischemic strokes]) during 24 months before mipomersen treatment, and in 9.6% of patients (10 patients with 13 events [1 cardiovascular death, 2 myocardial infarctions, 6 coronary interventions, 4 unstable angina episodes]) during a mean of 24.4 months after initiation of mipomersen (MACE rate 25.7 of 1000 patient-months vs 3.9 of 1000 patient-months, OR = 0.053 [95% CI, 0.016-0.168], P < .0001 by the exact McNemar test). The reduction in MACE coincided with a mean absolute reduction in LDL-C of 70 mg/dL (-28%) and of non-HDL cholesterol of 74 mg/dL (-26%) as well as reduction in Lp(a) of 11 mg/dL (-17%).

CONCLUSION

Long-term mipomersen treatment not only lowers levels of atherogenic lipoproteins but may also lead to a reduction in cardiovascular events in FH patients.

Long-term therapeutic efficacy of lipoprotein apheresis on circulating oxidative stress parameters--A comparison of two different apheresis techniques

BACKGROUND

A chronic lipoprotein apheresis therapy leads to an expressed reduction in the incidence of cardiovascular events in high-risk patients. In addition to the elimination of atherogenic lipoproteins such as LDL and lipoprotein(a), an antioxidative effect of lipoprotein apheresis has been suspected.

OBJECTIVES AND METHODS

We investigated long-term biochemical effects in sixteen patients undergoing lipoprotein apheresis - lipid filtration (LF, n = 7) or dextran sulfate adsorption (DSA, n = 9). Systemic oxidative stress markers (blood phagocyte chemiluminescence, levels of oxidized LDL and antioxLDL antibodies) were examined at the 1st, 40th and 80th apheresis sessions.

RESULTS

In DSA patients, the 80th apheresis session was associated with significantly higher LDL cholesterol removal and lower HDL cholesterol deprivation as compared to LF patients. In contrast to LF patients, DSA patients showed a long-term progressive decrease in circulating oxidant generating activity as evaluated by whole blood chemiluminescence (p < 0.05). Moreover, a single LF apheresis session was associated with higher systemic generation of reactive oxygen species over time.

CONCLUSION

Compared to LF, long-term DSA apheresis is associated with a gradual reduction of circulating oxidative burden and may be considered a beneficial molecular mechanism of this technique.

Current therapies for lowering lipoprotein (a)

Lipoprotein (a) [Lp(a)] is a human plasma lipoprotein with unique structural and functional characteristics. Lp(a) is an assembly of two components: a central core with apoB and an additional glycoprotein, called apo(a). Ever since the strong association between elevated levels of Lp(a) and an increased risk for CVD was recognized, interest in the therapeutic modulation of Lp(a) levels has increased. Here, the past and present therapies aiming to lower Lp(a) levels will be reviewed, demonstrating that these agents have had varying degrees of success. The next challenge will be to prove that Lp(a) lowering also leads to cardiovascular benefit in patients with elevated Lp(a) levels. Therefore, highly specific and potent Lp(a)-lowering strategies are awaited urgently.

Lipoprotein apheresis: present and future uses

PURPOSE OF REVIEW

For the past 40 years, apheresis, in particular, lipoprotein apheresis, has been the therapy of choice to lower LDL-C for familial hypercholesterolemia patients with uncontrolled dyslipidemia and cardiovascular disease. With the advent of recent and future lipid-modifying agents and their ability to lower LDL-C, the question arises on what will be the future of lipoprotein apheresis.

RECENT FINDINGS

Lipoprotein apheresis lowers not only plasma levels of apolipoprotein B lipoproteins but also markers of vascular inflammation and blood rheology. Other vascular diseases, not necessarily associated with familial hypercholesterolemia, such as nephrotic syndrome and peripheral arterial disease have profited from lipoprotein apheresis therapy. In 2013, the Food and Drug Administration approved lipoprotein apheresis therapy for patients with focal segmental glomerulosclerosis. Since 2010, the German healthcare ministry has approved lipoprotein apheresis therapy for patients with an elevated lipoprotein(a) and ongoing cardiovascular disease irrespective of LDL-C levels.

SUMMARY

Recent and future lipid-modifying therapies will most likely reduce the practice of lipoprotein apheresis therapy for familial hypercholesterolemia patients. Future implications for lipoprotein apheresis will involve vascular diseases that are at present lacking clinically effective therapy, whereas acute and chronic reductions of lipids, vascular inflammation, and/or rheology may improve the clinical outcome.

Antisense therapy targeting apolipoprotein(a): a randomised, double-blind, placebo-controlled phase 1 study

BACKGROUND

Lipoprotein(a) (Lp[a]) is a risk factor for cardiovascular disease and calcific aortic valve stenosis. No effective therapies to lower plasma Lp(a) concentrations exist. We have assessed the safety, pharmacokinetics, and pharmacodynamics of ISIS-APO(a)Rx, a second-generation antisense drug designed to reduce the synthesis of apolipoprotein(a) (apo[a]) in the liver.

METHODS

In this randomised, double-blind, placebo-controlled, phase 1 study at the PAREXEL Clinical Pharmacology Research Unit (Harrow, Middlesex, UK), we screened for healthy adults aged 18-65 years, with a body-mass index less than 32·0 kg/m(2), and Lp(a) concentration of 25 nmol/L (100 mg/L) or more. Via a randomisation technique, we randomly assigned participants to receive a single subcutaneous injection of ISIS-APO(a)Rx (50 mg, 100 mg, 200 mg, or 400 mg) or placebo (3:1) in the single-dose part of the study or to receive six subcutaneous injections of ISIS-APO(a)Rx (100 mg, 200 mg, or 300 mg, for a total dose exposure of 600 mg, 1200 mg, or 1800 mg) or placebo (4:1) during a 4 week period in the multi-dose part of the study. Participants, investigators, and study staff were masked to the treatment assignment, except for the pharmacist who prepared the ISIS-APO(a)Rx or placebo. The primary efficacy endpoint was the percentage change from baseline in Lp(a) concentration at 30 days in the single-dose cohorts and at 36 days for the multi-dose cohorts. Safety and tolerability was assessed 1 week after last dose and included determination of the incidence, severity, and dose relation of adverse events and changes in laboratory variables, including lipid panel, routine haematology, blood chemistry, urinalysis, coagulation, and complement variables. Other assessments included vital signs, a physical examination, and 12-lead electrocardiograph. This trial is registered with European Clinical Trials Database, number 2012-004909-27.

FINDINGS

Between Feb 27, 2013, and July 15, 2013, 47 (23%) of 206 screened volunteers were randomly assigned to receive ISIS-APO(a)Rx as a single-dose or multi-dose of ascending concentrations or placebo. In the single-dose study, we assigned three participants to receive 50 mg ISIS-APO(a)Rx, three participants to receive 100 mg ISIS-APO(a)Rx, three participants to receive 200 mg ISIS-APO(a)Rx, three participants to receive 400 mg ISIS-APO(a)Rx, and four participants to receive placebo. All 16 participants completed treatment and follow-up and were included in the pharmacodynamics, pharmacokinetics, and safety analyses. For the multi-dose study, we assigned eight participants to receive six doses of 100 mg ISIS-APO(a)Rx, nine participants to receive six doses of 200 mg ISIS-APO(a)Rx, eight participants to receive six doses of 300 mg ISIS-APO(a)Rx, and six participants to receive six doses of placebo. Whereas single doses of ISIS-APO(a)Rx (50-400 mg) did not decrease Lp(a) concentrations at day 30, six doses of ISIS-APO(a)Rx (100-300 mg) resulted in dose-dependent, mean percentage decreases in plasma Lp(a) concentration of 39·6% from baseline in the 100 mg group (p=0·005), 59·0% in the 200 mg group (p=0·001), and 77·8% in the 300 mg group (p=0·001). Similar reductions were observed in the amount of oxidized phospholipids associated with apolipoprotein B-100 and apolipoprotein(a). Mild injection site reactions were the most common adverse events.

INTERPRETATION

ISIS-APO(a)Rx results in potent, dose-dependent, selective reductions of plasma Lp(a). The safety and tolerability support continued clinical development of ISIS-APO(a)Rx as a potential therapeutic drug to reduce the risk of cardiovascular disease and calcific aortic valve stenosis in patients with elevated Lp(a) concentration.

FUNDING

Isis Pharmaceuticals.

'LDL-C' = LDL-C + Lp(a)-C: implications of achieved ultra-low LDL-C levels in the proprotein convertase subtilisin/kexin type 9 era of potent LDL-C lowering

PURPOSE OF REVIEW

The measurement that is termed 'LDL-cholesterol' (LDL-C) includes the cholesterol content of lipoprotein(a) [Lp(a)-C], which can contribute approximately 30-45% to measured LDL-C levels as a percentage of its mass. We review the implications of achieved very low LDL-C levels in patients treated with potent LDL-C-lowering agents in the context of varying Lp(a) levels.

RECENT FINDINGS

Combination therapy with statins, ezetimibe, and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors can lower LDL-C to unprecedentedly low levels. Recent PCSK9 trials have shown that routine achievement of mean LDL-C less than 50 mg/dl is feasible, along with the modest reductions in Lp(a). Many patients will achieve LDL-C less than 25 mg/dl with concomitantly elevated Lp(a) levels that contribute substantially to the measured 'LDL-C'. Therefore, it is possible that some of these patients may have little to no circulating LDL-C.

SUMMARY

As the new era of ultralow LDL-C levels ensues, it is imperative to understand the contribution of Lp(a)-C to measured LDL-C and the consequences of achieving ultralow or potentially absent LDL-C in the setting of elevated Lp(a) levels and possibly free apo(a). We review this concept and suggest avenues of research, including analyses of existing datasets in current clinical trials and new research studies, to understand its pathophysiological and clinical significance.

Homozygous autosomal dominant hypercholesterolaemia: prevalence, diagnosis, and current and future treatment perspectives

PURPOSE OF REVIEW

Homozygous autosomal dominant hypercholesterolemia (hoADH) is a rare genetic disorder caused by mutations in LDL receptor, apolipoprotein B, and/or proprotein convertase subtilisin-kexin type 9. Both the genetic mutations and the clinical phenotype vary largely among individual patients, but patients with hoADH are typically characterized by extremely elevated LDL-cholesterol (LDL-C) levels, and a very high-risk for premature cardiovascular disease. Current lipid-lowering therapies include bile acid sequestrants, statins, and ezetimibe. To further decrease LDL-C levels in hoADH, lipoprotein apheresis is recommended, but this therapy is not available in all countries.

RECENT FINDINGS

Recently, the microsomal triglyceride transfer protein inhibitor lomitapide and the RNA antisense inhibitor of apolipoprotein B mipomersen were approved by the Food and Drug Administration/European Medicine Agency and the Food and Drug Administration, respectively. Several other LDL-C-lowering strategies and therapeutics targeting the HDL-C pathway are currently in the clinical stage of development.

SUMMARY

Novel therapies have been introduced for LDL-C-lowering and innovative drug candidates for HDL-C modulation for the treatment of hoADH. Here, we review the current available literature on the prevalence, diagnosis, and therapeutic strategies for hoADH.

What is the ultimate test that lowering lipoprotein(a) is beneficial for cardiovascular disease and aortic stenosis?

PURPOSE OF REVIEW

Lipoprotein(a) [Lp(a)] is a risk factor for cardiovascular disease (CVD) and calcific aortic valve stenosis. We review recent studies that highlight Lp(a) in CVD and calcific aortic valve stenosis and propose pathways to clinical registration of Lp(a)-lowering agents.

RECENT FINDINGS

Over the last few years, almost irrefutable evidence has accumulated that Lp(a) is a causal, independent, genetic risk factor for CVD. Most recently, new data have emerged that elevated Lp(a) is causally associated with calcific aortic valve stenosis and the need for aortic valve replacement. Three levels of evidence to support these findings: epidemiological studies, Mendelian randomization studies and genetic association studies. A dedicated Lp(a)-lowering trial has not been performed to date. Emerging Lp(a)-lowering therapies with specific and potent lowering of Lp(a) are in phase II clinical trials and provide a tool to test the hypothesis that lowering Lp(a) plasma levels will lead to clinical benefit.

SUMMARY

We provide a rationale for the potential clinical use of Lp(a)-lowering therapies in high-risk patients or patients with established CVD whose major risk factor is elevated Lp(a) levels and propose clinical studies and trials to demonstrate that lowering Lp(a) levels will effectively reduce the risk of calcific aortic valve stenosis and CVD.

The severe hypercholesterolemia phenotype: clinical diagnosis, management, and emerging therapies

The severe hypercholesterolemia phenotype includes all patients with marked elevation of low-density lipoprotein cholesterol (LDL-C) levels. The most common cause is autosomal dominant hypercholesterolemia, an inherited disorder caused by mutations either in LDL receptor, apolipoprotein B (APOB), or proprotein convertase subtilisin kexin type 9 (PCSK9) genes. However, it is now known that many subjects with severe inherited hypercholesterolemia have no defects in these genes. These cases are caused either by mutations in genes yet to be identified or are consequences of polygenic, epigenetic, or acquired defects. Because the clinical consequences of extreme hypercholesterolemia are the same no matter the cause, the focus should be on the identification of subjects with severe hypercholesterolemia, followed by phenotypic screening of family members. Genetic screening is not necessary to diagnose or initiate treatment for the severe hypercholesterolemia phenotype. Management of severe hypercholesterolemia is based on risk factor modification and use of multiple lipid-lowering medications. Lipoprotein apheresis is indicated for coronary artery disease (CAD) patients taking maximally tolerated therapy and with LDL-C levels >200 mg/dl (>300 mg/dl if without CAD). A microsomal triglyceride transfer protein inhibitor and an antisense oligonucleotide against APOB have recently been approved for use in subjects with clinically diagnosed homozygous familial hypercholesterolemia. PCSK9 inhibitors, currently in phase II and III trials, lower LDL-C up to an additional 70% in the setting of maximally tolerated medical therapy and have the potential to reduce LDL-C to <70 mg/dl in most patients. Early identification of affected individuals and aggressive treatment should significantly reduce the burden of cardiovascular disease in society.