Familial Hypercholesterolaemia Regression Study: a randomised trial of low-density-lipoprotein apheresis

Apheresis: What Should a Clinician Know?

PURPOSE OF REVIEW

Apheresis is a treatment option for severe dyslipidemia which has been introduced approximately 40 years ago to clinical practice. This article reviews recent apheresis research progresses, including apheresis for elevated LDL-cholesterol and elevated lipoprotein(a).

RECENT FINDINGS

While the role of apheresis in treating more common forms of LDL-hypercholesterolemia has been reduced due to the development of new, very potent LDL-lowering drugs, it still plays an important role in treating patients with homozygous familial hypercholesterolemia and patients with severe lipoprotein(a) elevation. One apheresis session can decrease LDL-cholesterol, apoB, and lipoprotein(a) by approximately 65%, which results in a time averaged reduction of 30-50%. Although time-consuming, and expensive regular apheresis is very well tolerated and has been proven safe for decades. Apheresis remains a treatment option for severe dyslipidemia, especially in homozygous familial hypercholesterolemia and elevated lipoprotein(a), if other forms of therapy fail to achieve targets.

Lipoprotein(a) and Atherosclerotic Cardiovascular Disease, the Impact of Available Lipid-Lowering Medications on Lipoprotein(a): An Update on New Therapies

OBJECTIVE

To review evidence of existing and new pharmacological therapies for lowering lipoprotein(a) (Lp[a]) concentrations and their impact on clinically relevant outcomes.

METHODS

We searched for literature pertaining to Lp(a) and pharmacological treatments in PubMed. We reviewed articles published between 1963 and 2020.

RESULTS

We found that statins significantly increased Lp(a) concentrations. Therapies that demonstrated varying degrees of Lp(a) reduction included ezetimibe, niacin, proprotein convertase subtilisin/kexin type 9 inhibitors, lipoprotein apheresis, fibrates, aspirin, hormone replacement therapy, antisense oligonucleotide therapy, and small interfering RNA therapy. There was limited data from large observational studies and post hoc analyses showing the potential benefits of these therapies in improving cardiovascular outcomes.

CONCLUSION

There are multiple lipid-lowering agents currently being used to treat hyperlipidemia that also have a Lp(a)-lowering effect. Two RNA therapies specifically targeted to lower Lp(a) are being investigated in phase 3 clinical trials and, thus far, have shown promising results. However, evidence is lacking to determine the clinical relevance of reducing Lp(a). At present, there is a need for large-scale, randomized, controlled trials to evaluate cardiovascular outcomes associated with lowering Lp(a).

Use of apheresis in the age of new therapies for familial hypercholesterolaemia

PURPOSE OF REVIEW

Lipoprotein apheresis has been first line therapy for homozygous familial hypercholesterolaemia (FH) and other severe and refractory forms of dyslpidaemia for over 40 years but the recent advent of novel and potent LDL-lowering compounds necessitates a reappraisal of its role.

RECENT FINDINGS

During the past decade a substantial amount of evidence has accumulated describing the effect of LDL-lowering with apheresis and conventional drug therapy upon the cardiovascular outcomes associated with homozygous and statin-refractory heterozygous FH. This has necessitated re-defining the target levels of LDL cholesterol needed to arrest progression of atherosclerosis in these situations. At the same time, evidence has accrued regarding the pathogenicity of raised levels of lipoprotein (a) and the promising role of apheresis in mitigating the adverse effects of the latter. The latest advance in treatment has been the introduction of three classes of novel and potent LDL-lowering compounds in the shape of inhibitors of Propertin convertase subtilisin kexin 9 (PCSK9), microsomal triglyceride transfer protein and angiopoietin-like 3.

SUMMARY

These recent developments raise the question of whether these compounds will be used as adjuvants to bolster lipoprotein apheresis in FH homozygotes or whether they will render it obsolete, as is already occurring with PCSK9 inhibitors in FH heterozygotes.

Lipoprotein(a) Lowering-From Lipoprotein Apheresis to Antisense Oligonucleotide Approach

It is well-known that elevated lipoprotein(a)—Lp(a)—levels are associated with a higher risk of cardiovascular (CV) mortality and all-cause mortality, although a standard pharmacotherapeutic approach is still undefined for patients with high CV risk dependent on hyperlipoproteinemia(a). Combined with high Lp(a) levels, familial hypercholesterolemia (FH) leads to a greater CVD risk. In suspected FH patients, the proportion of cases explained by a rise of Lp(a) levels ranges between 5% and 20%. In the absence of a specific pharmacological approach able to lower Lp(a) to the extent required to achieve CV benefits, the most effective strategy today is lipoprotein apheresis (LA). Although limited, a clear effect on Lp(a) is exerted by PCSK9 antagonists, with apparently different mechanisms when given with statins (raised catabolism) or as monotherapy (reduced production). In the era of RNA-based therapies, a new dawn is represented by the use of antisense oligonucleotides APO(a)L_rx, able to reduce Lp(a) from 35% to over 80%, with generally modest injection site reactions. The improved knowledge of Lp(a) atherogenicity and possible prevention will be of benefit for patients with residual CV risk remaining after the most effective available lipid-lowering agents.

Assessing Atherosclerotic Cardiovascular Disease Risk with Advanced Lipid Testing: State of the Science

Cardiovascular disease is the number one cause of death and disability worldwide. While substantial gains have been made in reducing cardiovascular mortality, future projections suggest that we have reached a nadir and may be at an inflection point, given the rising tide of obesity and diabetes. Evaluation and management of plasma lipids is central to the prevention of atherosclerotic cardiovascular disease. Although the standard lipid panel represents a well-established platform to assess risk, this test alone can be insufficient and/or misleading. Advances in our understanding of atherosclerosis have led to the development of lipid-based biomarkers that help to discriminate the risk of cardiovascular disease when it is unclear. While these biomarkers provide novel information, their implementation into clinical medicine remains difficult given discrepancies in the literature, lack of assay standardisation, poor accessibility and high cost. However, additional measures of atherogenic lipoproteins or their surrogates may offer insight beyond the standard lipid panel, providing a more precise assessment of risk and more accurate assessment of lipid-lowering therapy.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice - Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Eighth Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating and categorizing indications for the evidence-based use of therapeutic apheresis (TA) in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Eighth Edition of the JCA Special Issue continues to maintain this methodology and rigor in order to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Eighth Edition, like its predecessor, continues to apply the category and grading system definitions in fact sheets. The general layout and concept of a fact sheet that was introduced in the Fourth Edition, has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of TA in a specific disease entity or medical condition. The Eighth Edition comprises 84 fact sheets for relevant diseases and medical conditions, with 157 graded and categorized indications and/or TA modalities. The Eighth Edition of the JCA Special Issue seeks to continue to serve as a key resource that guides the utilization of TA in the treatment of human disease.

Current Role of Lipoprotein Apheresis

Purpose of Review

Lipoprotein apheresis is a very efficient but time-consuming and expensive method of lowering levels of low-density lipoprotein cholesterol, lipoprotein(a)) and other apoB containing lipoproteins, including triglyceride-rich lipoproteins. First introduced almost 45 years ago, it has long been a therapy of “last resort” for dyslipidaemias that cannot otherwise be managed. In recent years new, very potent lipid-lowering drugs have been developed and the purpose of this review is to define the role of lipoprotein apheresis in the current setting.

Recent Findings

Lipoprotein apheresis still plays an important role in managing patients with homozygous FH and some patients with other forms of hypercholesterolaemia and cardiovascular disease. In particular, patients not achieving treatment goals despite modern lipid-lowering drugs, either because these are not tolerated or the response is insufficient. Recently, lipoprotein(a) has emerged as an important cardiovascular risk factor and lipoprotein apheresis has been used to decrease lipoprotein(a) concentrations in patients with marked elevations and cardiovascular disease. However, there is considerable heterogeneity concerning the recommendations by scientific bodies as to which patient groups should be treated with lipoprotein apheresis.

Summary

Lipoprotein apheresis remains an important tool for the management of patients with severe drug-resistant dyslipidaemias, especially those with homozygous FH.

From lipoprotein apheresis to proprotein convertase subtilisin/kexin type 9 inhibitors: Impact on low-density lipoprotein cholesterol and C-reactive protein levels in cardiovascular disease patients

In this observational study, we compared the effect of lipoprotein apheresis and evolocumab or alirocumab on levels of lipoprotein cholesterol, triglycerides and inflammatory markers (C reactive protein and interleukin 6) in cardiovascular patients ( n = 9). Patients were monitored during the last year of lipoprotein apheresis followed by six months of treatment with proprotein convertase subtilisin/kexin type 9 inhibitors. The biochemical parameters were determined pre- and post- every apheresis procedure for 12 months and then after one, three and six months of treatment with evolocumab (140 mg every two weeks [Q2W]) or alirocumab (75 mg or 150 mg every two weeks [Q2W]). Lipoprotein apheresis significantly reduced low-density lipoprotein cholesterol levels from 138 ± 32 mg/dl to 46 ± 16 mg/dl ( p < 0.001), with an inter-apheresis level of 114 ± 26 mg/dl. Lipoprotein(a) was also reduced from a median of 42 mg/dl to 17 mg/dl ( p < 0.01). Upon anti-proprotein convertase subtilisin/kexin type 9 therapy, low-density lipoprotein cholesterol levels were similar to post-apheresis (59 ± 25, 41 ± 22 and 42 ± 21mg/dl at one, three and six months, respectively) as well as those of lipoprotein(a) (18 mg/dl). However, an opposite effect was observed on high-density lipoprotein cholesterol levels: –16.0% from pre- to post-apheresis and +34.0% between pre-apheresis and proprotein convertase subtilisin/kexin type 9 inhibitors. Apheresis significantly reduced high-sensitivity C-reactive protein levels (1.5 ± 1.2 mg/l pre-apheresis to 0.6 ± 0.6 mg/l post-apheresis), while no changes were found upon proprotein convertase subtilisin/kexin type 9 mAbs administration. In conclusion, our study demonstrated that, by switching from lipoprotein apheresis to anti-proprotein convertase subtilisin/kexin type 9 therapies, patients reached similar low-density lipoprotein cholesterol and lipoprotein(a) levels, increased those of high-density lipoprotein cholesterol, and showed no changes on high-sensitivity C-reactive protein.

Whole Blood Selective LDL-Apheresis: A Comparison of Two Different Adsorbers

The effects of LDL-apheresis with whole blood adsorption were compared in five patients with severe familial and ARH hypercholesterolemia, using two different sorbents, polyacrylic acid with the DALI system and dextran sulfate with the DX21 system. The patients were treated bimonthly with both systems at random. For each patient, the same number of procedures with both systems was considered, ranging from 2 to 11 for each technique. During a period of observation of 26 months, a total of 80 LDL-apheresis, 40 with the DALI system and 40 with the DX21, with equivalent volumes of treated whole blood was evaluated (mean blood volume treated: 8151 mL). Total and LDL cholesterol were effectively lowered with both techniques. The mean percentage reduction of total cholesterol and LDL-cholesterol respectively was 54.1±7.7% and 62.3±9% with the DALI system, 52.7±7.8% and 59.2±9.5 with the DX21: t-test for paired data showed p: 0.01 for LDL-cholesterol. The reduced removal of LDL-C with dextran sulfate, either within the same patient or all the patients taken together was of a very limited amount compared to polyacrylic acid. The superiority of one over the other sorbent cannot be affirmed: further studies on a higher number of procedures and patients, together with an evaluation of biocompatibility effects, compared to polyacrylic acid may clarify and make evident a significant difference in efficacy between the two systems.

Retrospective Comparison of 5 different Methods for Long-Term LDL-Apheresis in 20 Patients between 1986 and 2001

Purpose

To compare long-term efficacy and biocompatibility of the 5 most commonly applied LDL-apheresis techniques using a specifically modified calculation method of the area under the curve (AUC) for laboratory parameters.

Design

Retrospective long-term analysis of 20 patients with homozygous or severe heterozygous familial hypercholesterolemia.

Procedures

The following 5 extra-corporeal LDL-apheresis methods were compared: IMAL (Immuno Adsorption of Lipoproteins), DSA (Dextran Sulphate Adsorption), HELP (Heparin Induced Extra-corporeal LDL Precipitation), DALI (Direct Adsorption of Lipoproteins), MDF (Membrane Differential Filtration).

Main outcome measures

AUC derived plasma concentrations (CAUC) of lipoproteins between two apheresis procedures and their long-term course. Comparison of biocompatibility and efficacy concerning the LDL-C target of < 2.6 mmol/L of 5 apheresis techniques. Progression of atherosclerosis in patients with severe hypercholesterolemia.

Main findings

The means of AUC derived average plasma concentrations (CAUC) of all treatment intervals were for LDL-C and the LDL/HDL ratio as follows: IMAL (5.59 mmol/L; ratio 4.1), DSA (3.03 mmol/L; ratio 2.0), HELP (4.06 mmol/L; ratio 2.2), DALI (3.83 mmol/L; ratio 3.3), MDF (3.26 mmol/L; ratio 3.2). Coronary heart disease and cardiac events (myocardial infarction, PTCA/ stent implantation, CABG) progressed in only 2 patients whereas atherosclerosis manifestations (sclerosis abdominal aorta, carotid artery stenosis, peripheral vascular disease) worsened in 13 patients. Mean ergometric capacity improved from 112 to 118 Watt.

Conclusions

All 5 apheresis methods (IMAL, DSA, HELP, DALI, MDF) proved to be safe and suitable for long-term treatment in patients with severe hypercholesterolemia. The introduction of the CAUC revealed that the target of LDL-C < 2.6 mmol/L was not achieved with regard to the time averaged concentration (CAUC).

Familial hypercholesterolaemia

Familial hypercholesterolaemia is a common inherited disorder characterized by abnormally elevated serum levels of low-density lipoprotein (LDL) cholesterol from birth, which in time can lead to cardiovascular disease (CVD). Most cases are caused by autosomal dominant mutations in LDLR, which encodes the LDL receptor, although mutations in other genes coding for proteins involved in cholesterol metabolism or LDLR function and processing, such as APOB and PCSK9, can also be causative, although less frequently. Several sets of diagnostic criteria for familial hypercholesterolaemia are available; common diagnostic features are an elevated LDL cholesterol level and a family history of hypercholesterolaemia or (premature) CVD. DNA-based methods to identify the underlying genetic defect are desirable but not essential for diagnosis. Cascade screening can contribute to early diagnosis of the disease in family members of an affected individual, which is crucial because familial hypercholesterolaemia can be asymptomatic for decades. Clinical severity depends on the nature of the gene that harbours the causative mutation, among other factors, and is further modulated by the type of mutation. Lifelong LDL cholesterol-lowering treatment substantially improves CVD-free survival and longevity. Statins are the first-line therapy, but additional drugs, such as ezetimibe, bile acid sequestrants, PCSK9 inhibitors and other emerging therapies, are often required.

Emerging Therapeutic Options for Lowering of Lipoprotein(a): Implications for Prevention of Cardiovascular Disease

PURPOSE OF REVIEW

Elevated plasma concentrations of lipoprotein(a) (Lp(a)) are an independent and causal risk factor for cardiovascular diseases including coronary artery disease, ischemic stroke, and calcific aortic valve stenosis. This review summarizes the rationale for Lp(a) lowering and surveys relevant clinical trial data using a variety of agents capable of lowering Lp(a).

RECENT FINDINGS

Contemporary guidelines and recommendations outline populations of patients who should be screened for elevated Lp(a) and who might benefit from Lp(a) lowering. Therapies including drugs and apheresis have been described that lower Lp(a) levels modestly (∼20 %) to dramatically (∼80 %). Existing therapies that lower Lp(a) also have beneficial effects on other aspects of the lipid profile, with the exception of Lp(a)-specific apheresis and an antisense oligonucleotide that targets the mRNA encoding apolipoprotein(a). No clinical trials conducted to date have managed to answer the key question of whether Lp(a) lowering confers a benefit in terms of ameliorating cardiovascular risk, although additional outcome trials of therapies that lower Lp(a) are ongoing. It is more likely, however, that Lp(a)-specific agents will provide the most appropriate approach for addressing this question.

Lipoprotein apheresis to treat elevated lipoprotein (a)

An elevated plasma concentration of lipoprotein (a) [Lp(a)] is an independent risk factor for cardiovascular disease. Life style modification and currently available drugs either fail to effectively lower plasma Lp(a) levels or do not result in clinical benefit. However, lipoprotein apheresis is very efficient in decreasing Lp(a) concentrations. A single apheresis session can acutely decrease Lp(a) by approximately 60-75%, and apheresis performed weekly or biweekly results in considerably decreased mean interval concentrations (approximately 25-40% reduction). While most apheresis systems (heparin-induced extracorporeal LDL precipitation, direct adsorption of lipoproteins, lipoprotein apheresis with dextran-sulfate, lipid filtration, immunoadsorption) decrease LDL and Lp(a), Lipopac is specific and only decreases Lp(a). Lp(a) apheresis is expensive and time consuming, but associated with very few side effects. Two randomized controlled trials give conflicting consults with respect to the effect on angiographic changes. Retrospective analyses indicate that regular apheresis translates into clinical benefit in patients with elevated Lp(a), but adequate randomized controlled trials are lacking.

Usefulness of lipid apheresis in the treatment of familial hypercholesterolemia

Lipid apheresis is used to treat patients with severe hyperlipidemia by reducing low-density lipoprotein cholesterol (LDL-C). This study examines the effect of apheresis on the lipid panel and cardiac event rates before and after apheresis. An electronic health record screen of ambulatory patients identified 11 active patients undergoing lipid apheresis with 10/11 carrying a diagnosis of FH. Baseline demographics, pre- and postapheresis lipid levels, highest recorded LDL-C, cardiac events, current medications, and first apheresis treatment were recorded. Patients completed a questionnaire and self-reported risk factors and interest in alternative treatment. There were significant reductions in mean total cholesterol (−58.4%), LDL-C (−71.9%), triglycerides (−51%), high-density lipoprotein (HDL) cholesterol (−9.3%), and non-HDL (−68.2%) values. Thirty-four cardiac events were documented in 8 patients before apheresis, compared with 9 events in 5 patients after apheresis. Our survey showed a high prevalence of statin intolerance (64%), with the majority (90%) of participants indicating an interest in alternative treatment options. Our results have shown that lipid apheresis primary effect is a marked reduction in LDL-C cholesterol levels and may reduce the recurrence of cardiac events. Apheresis should be compared to the newer alternative treatment modalities in a randomized fashion due to patient interest in alternative options.

[Clinical significance of and treatment options for increased lipoprotein(a)]

Lipoprotein(a) has been shown to be associated with an increased incidence of cardiovascular diseases for decades. However, only recent research revealed more about its physiological function and its role in the development of cardiovascular diseases. The authors summarize the physiological role of lipoprotein(a), causes and treatment of elevated lipoprotein(a) level, and the association between lipoprotein(a) and cardiovascular diseases.

Lipoprotein apheresis and new therapies for severe familial hypercholesterolemia in adults and children

Familial hypercholesterolemia (FH), the most common and severe monogenic form of hypercholesterolemia, is an autosomal co-dominant disease characterized by an increased plasma low density lipoprotein (LDL)-cholesterol concentration and premature coronary heart disease (CHD). The clinical phenotype depends on the gene involved and severity of mutation (or mutations) present. Patients with homozygous or compound heterozygous FH have severe hypercholesterolemia (LDL-cholesterol >13 mmol/L) due to a gene dosing effect and without treatment have accelerated atherosclerotic CHD from birth, and frequently die of CHD before age 30. Cholesterol-lowering therapies have been shown to reduce both mortality and major adverse cardiovascular events in individuals with FH. Lipoprotein apheresis concomitant with lipid-lowering therapy is the treatment of choice for homozygous FH. This article describes the rationale and role of lipoprotein apheresis in the treatment of severe FH and outlines the recent advances in new pharmacotherapies for this condition.

New therapies to reduce low-density lipoprotein cholesterol

PURPOSE OF REVIEW

Lipid-lowering is an intervention that reduces atherosclerosis and its complications. Statins currently form the standard of care but are not able to reduce low-density lipoprotein cholesterol (LDL-C) adequately in all patients - particularly those with familial hypercholesterolaemia and those with statin intolerance.

RECENT FINDINGS

Combination therapy with statins is well established and ezetimibe is often used as an additional LDL-C-lowering agent reducing LDL-C by 20%. However, its clinical efficacy still remains controversial. Newer, more potent methods of LDL-C reduction are in development. Both lomitapide, a microsomal transfer protein inhibitor (MTPI), and mipomersen, an antisense oligonucleotide (ASO), have been shown to improve LDL-C levels by 25-50% in patients with homozygous familial hypercholesterolaemia. In patients with heterozygous familial hypercholesterolaemia or statin intolerance antibody-based inhibitors of preprotein convertase subtilisin/kexin 9 (PCSK9) produce reductions in LDL-C of 30-65%. Cholesterol ester transfer protein inhibitors (CETPIs) reduce LDL-C by 30-40% as well as raising levels of high-density lipoprotein cholesterol (HDL-C) and may also have a role as additional LDL-C-reducing drugs.

SUMMARY

Surrogate outcome trials will be required with lomitapide or mipomersen to confirm their effects in homozygous familial hypercholesterolaemia and clinical endpoint trials will be needed for PCSK9 and CETPIs if these are to be used widely.

Current Treatment of Familial Hypercholesterolaemia

Familial hypercholesterolaemia is an autosomal-dominant disorder associated with mutations in the LDL receptor gene resulting in markedly elevated plasma low-density lipoprotein cholesterol levels. FH is significantly underrecognised with as many as 1 in 300 having the heterozygous form and 1 in 1 million having the homozygous form of the disease. Early diagnosis and treatment of FH is paramount to reduce the risk of premature atherosclerotic cardiovascular disease and death. The goal of treatment is to reduce LDL-C by 50 % from baseline levels with lifestyle modification, pharmacologic lipid-lowering therapy, LDL apheresis and in rare cases, liver transplantation. Pharmacologic treatment ranges from statin medications to newer agents such as lomitapide, mipomersin and PCSK9 inhibitors. Combination therapy is frequently required to achieve goal lipoprotein level reductions and prevent complications.

Lipoprotein(a) for risk assessment in patients with established coronary artery disease

OBJECTIVES

The purpose of this study was to assess the prognostic utility of lipoprotein(a) [Lp(a)] in individuals with coronary artery disease (CAD).

BACKGROUND

Data regarding an association between Lp(a) and cardiovascular (CV) risk in secondary prevention populations are sparse.

METHODS

Plasma Lp(a) was measured in 6,708 subjects with CAD from 3 studies; data were then combined with 8 previously published studies for a total of 18,978 subjects.

RESULTS

Across the 3 studies, increasing levels of Lp(a) were not associated with the risk of CV events when modeled as a continuous variable (odds ratio [OR]: 1.03 per log-transformed SD, 95% confidence interval [CI]: 0.96 to 1.11) or by quintile (Q5:Q1 OR: 1.05, 95% CI: 0.83 to 1.34). When data were combined with previously published studies of Lp(a) in secondary prevention, subjects with Lp(a) levels in the highest quantile were at increased risk of CV events (OR: 1.40, 95% CI: 1.15 to 1.71), but with significant between-study heterogeneity (p = 0.001). When stratified on the basis of low-density lipoprotein (LDL) cholesterol, the association between Lp(a) and CV events was significant in studies in which average LDL cholesterol was ≥130 mg/dl (OR: 1.46, 95% CI: 1.23 to 1.73, p < 0.001), whereas this relationship did not achieve statistical significance for studies with an average LDL cholesterol <130 mg/dl (OR: 1.20, 95% CI: 0.90 to 1.60, p = 0.21).

CONCLUSIONS

Lp(a) is significantly associated with the risk of CV events in patients with established CAD; however, there exists marked heterogeneity across trials. In particular, the prognostic value of Lp(a) in patients with low cholesterol levels remains unclear.

The evidence-base for the efficacy of lipoprotein apheresis in combating cardiovascular disease

OBJECTIVE

To review the evidence supporting the use of lipoprotein apheresis to treat severe forms of dyslipidaemia that predispose to cardiovascular disease and are refractory to conventional therapy.

METHODS

Review of relevant publications based on personal knowledge and a search of the literature from the past 10 years using PubMed.

RESULTS

There is good evidence that drastic lowering of LDL by lipoprotein apheresis increases longevity in homozygous familial hypercholesterolaemia (FH) and decreases cardiovascular morbidity in FH heterozygotes refractory to or intolerant of statins. Lipoprotein apheresis may also decrease cardiovascular events in patients with raised levels of Lp(a) but further data are needed.

CONCLUSIONS

Lipoprotein apheresis currently provides a therapeutic life-line for a small number of very high risk patients. It remains to be seen what effect the recent emergence of several novel and powerful lipid-lowering drugs will have on its future role in that respect.

Differences in the atherogenic risk of patients treated by lipoprotein apheresis according to their lipid pattern

In high-risk patients who are already on a maximal lipid-lowering therapy, a lipoprotein apheresis is an important therapeutic option in preventing further progress of vascular complications as it may decrease both LDL-cholesterol (LDL-C) and lipoprotein(a) (Lp(a)) levels. We looked at the occurrence of cardiovascular events before apheresis and during apheresis in three groups defined by their lipid patterns at the start of an apheresis treatment: Group 1 (LDL-C ≥ 3.4 mmol/l and Lp(a) ≤ 600 mg/l; n = 35), Group 2 (LDL-C ≤ 3.4 mmol/l and Lp(a) ≥ 600 mg/l n = 37) and Group 3 (LDL-C ≥ 3.4 mmol/l and Lp(a) ≥ 600 mg/l; n = 15). Group 2 shows a time period of about 10 years from the first event until the start of apheresis treatment (compared to 2-6 years in the other two groups). Before the start of apheresis treatment 2.1 events per patient had occurred in Group 1, 3.4 events per patient in Group 2 and 1.8 events per patient in Group 3. Under apheresis therapy just 0.9 events per patient occurred in Group 1, 0.5 in Group 2 and 0.5 in Group 3. When comparing the two years before the start of apheresis treatment with the first two years under apheresis we saw the following reduction rates of cardiovascular events: Group 1-54%; Group 2-83%; Group 3-83.5%. Our results show that the reduction of cardiovascular events due to lipoprotein apheresis is especially high in patients with elevated levels of Lp(a) compared to patients with elevated LDL-C only indicating that physicians should be more focused on the risk factor elevated Lp(a).

Lomitapide: a review of its use in adults with homozygous familial hypercholesterolemia

Lomitapide (Juxtapid(TM)), an orally administered inhibitor of the microsomal triglyceride transfer protein, inhibits the synthesis of chylomicrons and very low-density lipoprotein, thereby reducing plasma levels of low-density lipoprotein cholesterol (LDL-C). Lomitapide is used to lower lipid levels in adults with homozygous familial hypercholesterolemia, a rare, potentially life-threatening genetic disease that is commonly caused by mutations in the LDL receptor gene or other genes that affect the function of the LDL receptor. In a multinational single-arm, open-label, 78-week, phase III trial, lomitapide reduced mean plasma LDL-C levels by 50 % from baseline in 23 evaluable adults with homozygous familial hypercholesterolemia over a 26 week treatment period. Reductions from baseline in LDL-C levels were sustained for up to 78 weeks with continued lomitapide treatment. In this study, the initial dosage of lomitapide was 5 mg once daily for two weeks, with upward titration thereafter to 10, 20, 40, and 60 mg at weeks 2, 6, 10, and 14, respectively, or until an individually assessed maximum dosage was achieved. Prior to the start of treatment with lomitapide, other lipid-lowering therapy (including LDL apheresis) was stabilized over a 6-week period, and then continued throughout the lomitapide treatment phase. Lomitapide was generally well tolerated; the most common adverse events in the phase III trial were gastrointestinal events.

Guidelines for the management of familial hypercholesterolemia

Familial hypercholesterolemia (FH) is a highly prevalent autosomal dominant hereditary disease, generally characterized by three major signs, hyper-low-density-lipoprotein (LDL) cholesterolemia, tendon/skin xanthomas and premature coronary artery disease (CAD). Because the risk of CAD is very high in these patients, they should be identified at an early stage of their lives and started on intensive treatment to control LDL-cholesterol. We here introduce a new guideline for the management of FH patients in Japan intending to achieve better control to prevent CAD. Diagnostic criteria for heterozygous FH are 2 or more of 1) LDL-cholesterol ≥180 mg/dL, 2) tendon/skin xanthoma(s), and 3) family history of FH or premature CAD within second degree relatives, for adults; and to have both 1) LDL-cholesterol ≥140 mg/dL and 2) family history of FH or premature CAD within second degree relatives, for children. For the treatment of adult heterozygous FH, intensive lipid control with statins and other drugs is necessary. Other risks of CAD, such as smoking, diabetes mellitus, hypertension etc., should also be controlled strictly. Atherosclerosis in coronary, carotid, or peripheral arteries, the aorta and aortic valve should be screened periodically. FH in children, pregnant women, and women who wish to bear a child should be referred to specialists. For homozygotes and severe heterozygotes resistant to drug therapies, LDL apheresis should be performed. The treatment cost of homozygous FH is authorized to be covered under the program of Research on Measures against Intractable Diseases by the Japanese Ministry of Health, Labour, and Welfare.

Lipid apheresis techniques: current status in Germany

For long-term lipid apheresis therapy, several different technical systems have been developed which enable effective reduction of LDL cholesterol and other atherogenic lipoproteins, such as Lp(a), with sufficient selectivity and good clinical tolerance. Suitable techniques include whole blood adsorption with polyacrylamide and dextran sulfate cellulose, while primary plasma separation is used for cascade filtration, heparin-induced precipitation, immunoadsorption, silicate gel adsorption, and dextran sulfate cellulose (both techniques).

The technical features are described. Only intensive training and experience of the medical personnel guarantees reliable treatment safety of all systems at a very low rate of minor side effects.

Role of lipid apheresis in changing times

During the last decades, LDL-apheresis was established as an extracorporeal treatment option for patients with severe heterozygous or homozygous familial hypercholesterolemia (FH) that is resistant to conventional treatment strategies such as diet, drugs, and changes in lifestyle. Nearly half a century ago, the first LDL-apheresis treatment was performed by plasma exchange in a child with homozygous FH. At the beginning of the 1970s, the clinical advantage of regular extracorporeal LDL-elimination was demonstrated in siblings suffering from homozygous FH. These findings encouraged researchers especially from Germany and Japan to develop extracorporeal devices to selectively eliminate LDL-cholesterol in the 1980s. Although the selectivity of the currently available LDL-apheresis devices is different, the efficacy of LDL-elimination during a single treatment is rather similar and ranges between 55 and 65 % of the pretreatment LDL plasma concentration.In the 1990s, the patients regularly treated by extracorporeal LDL-elimination, diet, and drugs were included in regression studies assessed by angiography. It was shown that the combined treatment with LDL-apheresis, diet, and drugs resulted in less progression of coronary lesions than drugs and/or diet alone. However, although a tendency was evident, results did not reach criteria for significance. During the last decade, apheresis registries were established to collect data on efficiency, safety, and clinical outcome of regular long-term LDL-apheresis. The evaluation of registry data will certainly permit further insights in the therapeutic benefit of this expensive and time-consuming therapeutic approach. Furthermore, the future of LDL-apheresis will depend upon the availability of highly efficient new drugs and molecular genetic approaches such as RNA silencing of the apoB gene, whereas the liver transplantation and gene therapy of the LDL-receptor deficiency will not replace LDL-apheresis in severe familial hypercholesterolemia in the near future.

Treatment of symptomatic HyperLp(a)lipoproteinemia with LDL-apheresis: a multicentre study

LDL-apheresis (LDLa) efficacy in the treatment of symptomatic HyperLp(a)lipoproteinemia -HyperLp(a)- has been studied in a multicentre trial. After 3.1+/-2.7 years of weekly and biweekly treatment, the data from 19 patients (males:12; females:7; aged 53.8+/-9.3 years; mean body mass index: 24.6+/-2.3 Kg/m²) were evaluated. Data were collected using the same questionnaire shared by 5 participating centres. A total of 2331 procedures were performed. A mean of 3593.7+/-800.3 ml of plasma or 8115.3+/-2150.1 ml of blood, depending upon the technique used (H.E.L.P., D.A.LI., Dextransulphate, Lipocollect 200), was regularly treated on average every 10.1+/-2.6 days. Baseline mean Lp(a) levels were 172.3+/-153.8 mg/dL. The mean pre-/post-apheresis Lp(a) levels decreased from 124.5+/-107.2 mg/dL (p<0.001 vs baseline) to 34.2+/-40.6 mg/dL (p<0.001 vs pre-). Baseline mean LDL-cholesterol (LDLC) levels were 152.3+/-74.6 mg/dL. The mean pre-/post-apheresis LDLC levels decreased from 130.4+/-61.1 mg/dL (p<0.004 vs baseline) to 41.2+/-25.1 mg/dL (p<0.001 vs pre-). The hypolipidemic drugs given to the patients during LDLa were: ezetimibe+simvastatin, atorvastatin, rosuvastatin, pravastatin, acipimox, and omega-3 fatty acids. 58% of the patients had arterial hypertension. Cigarette smokers were 5.3%. Alcohol intake was present in 21%. 52.6% were physically active. Patients with coronary artery disease (CAD) submitted to coronary catheterization before LDLa were 95%. In 5.5% (#1) CAD recurred despite treatment with LDLa. 79% were submitted to coronary revascularization before LDLa. CAD was: monovasal in 8 patients (42.1%), bivasal in 5 (26.4%), trivasal in 4 (21%), plurivasal in 2 (10.5%). In 94.5% of the sample the lesions were stable (< 0% deviation) over 3.1+/-2.7 years. 37% had both CAD and extra-coronary artery disease. This multicentre study confirmed that long-term treatment with LDLa was at least able to stabilize CAD in the majority of the individuals with symptomatic HyperLp(a).

Mipomersen, an antisense apolipoprotein B synthesis inhibitor

INTRODUCTION

mipomersen is a second-generation antisense oligonucleotide (ASO) targeted to human apolipoprotein (apo) B-100, a large protein synthesized by the liver that plays a fundamental role in human lipoprotein metabolism. Mipomersen predominantly distributes to the liver and decreases the production of apoB-100, the primary structural protein of the atherogenic lipoproteins including low density lipoprotein (LDL), thereby reducing plasma LDL-cholesterol and apoB-100 concentrations.

AREAS COVERED

the mode of action, preclinical development and clinical trials of mipomersen, an antisense apoB synthesis inhibitor. The paper provides an understanding of the pharmacokinetic and pharmacodynamic characteristics of mipomersen and insight into its clinical efficacy and safety. In clinical trials, mipomersen produced dose-dependent and prolonged reductions in LDL-cholesterol and other apoB-containing lipoproteins, including lipoprotein (a) [Lp(a)] in healthy volunteers and in patients with mild to moderate hypercholesterolemia. Mipomersen has been shown to decrease apoB, LDL-cholesterol and Lp(a) in patients with heterozygous and homozygous familial hypercholesterolemia on maximally tolerated lipid-lowering therapy.

EXPERT OPINION

mipomersen shows promise as an adjunctive agent by reducing apoB-containing lipoproteins in patients at high risk of atherosclerotic cardiovascular disease who are not at target or are intolerant of statins. Although the short-term efficacy and safety of mipomersen has been established, concern exists regarding the long-term potential for hepatic steatosis with this ASO.

Gene therapy in a humanized mouse model of familial hypercholesterolemia leads to marked regression of atherosclerosis

Background

Familial hypercholesterolemia (FH) is an autosomal codominant disorder caused by mutations in the low-density lipoprotein receptor (LDLR) gene. Homozygous FH patients (hoFH) have severe hypercholesterolemia leading to life threatening atherosclerosis in childhood and adolescence. Mice with germ line interruptions in the Ldlr and Apobec1 genes (Ldlr^−/−Apobec1^−/−) simulate metabolic and clinical aspects of hoFH, including atherogenesis on a chow diet.

Methods/Principal Findings

In this study, vectors based on adeno-associated virus 8 (AAV8) were used to deliver the gene for mouse Ldlr (mLDLR) to the livers of Ldlr^−/−Apobec1^−/− mice. A single intravenous injection of AAV8.mLDLR was found to significantly reduce plasma cholesterol and non-HDL cholesterol levels in chow-fed animals at doses as low as 3×10⁹ genome copies/mouse. Whereas Ldlr^−/−Apobec1^−/− mice fed a western-type diet and injected with a control AAV8.null vector experienced a further 65% progression in atherosclerosis over 2 months compared with baseline mice, Ldlr^−/−Apobec1^−/− mice treated with AAV8.mLDLR realized an 87% regression of atherosclerotic lesions after 3 months compared to baseline mice. Immunohistochemical analyses revealed a substantial remodeling of atherosclerotic lesions.

Conclusions/Significance

Collectively, the results presented herein suggest that AAV8-based gene therapy for FH may be feasible and support further development of this approach. The pre-clinical data from these studies will enable for the effective translation of gene therapy into the clinic for treatment of FH.