Lipoprotein Apheresis

Oral agents for lowering lipoprotein(a)

PURPOSE OF REVIEW

To review the development of oral agents to lower Lp(a) levels as an approach to reducing cardiovascular risk, with a focus on recent advances in the field.

RECENT FINDINGS

Extensive evidence implicates Lp(a) in the causal pathway of atherosclerotic cardiovascular disease and calcific aortic stenosis. There are currently no therapies approved for lowering of Lp(a). The majority of recent therapeutic advances have focused on development of injectable agents that target RNA and inhibit synthesis of apo(a). Muvalaplin is the first, orally administered, small molecule inhibitor of Lp(a), which acts by disrupting binding of apo(a) and apoB, in clinical development. Nonhuman primate and early human studies have demonstrated the ability of muvalaplin to produce dose-dependent lowering of Lp(a). Ongoing clinical trials will evaluate the impact of muvalaplin in high cardiovascular risk and will ultimately need to determine whether this strategy lowers the rate of cardiovascular events.

SUMMARY

Muvalaplin is the first oral agent, developed to lower Lp(a) levels. The ability of muvalaplin to reduce cardiovascular risk remains to be investigated, in order to determine whether it will be a useful agent for the prevention of cardiovascular disease.

Therapeutic Potential of Lipoprotein(a) Inhibitors

Increasing evidence has implicated lipoprotein(a) [Lp(a)] in the causality of atherosclerosis and calcific aortic stenosis. This has stimulated immense interest in developing novel approaches to integrating Lp(a) into the setting of cardiovascular prevention. Current guidelines advocate universal measurement of Lp(a) levels, with the potential to influence cardiovascular risk assessment and triage of higher-risk patients to use of more intensive preventive therapies. In parallel, considerable activity has been undertaken to develop novel therapeutics with the potential to achieve selective and substantial reductions in Lp(a) levels. Early studies of antisense oligonucleotides (e.g., mipomersen, pelacarsen), RNA interference (e.g., olpasiran, zerlasiran, lepodisiran) and small molecule inhibitors (e.g., muvalaplin) have demonstrated effective Lp(a) lowering and good tolerability. These agents are moving forward in clinical development, in order to determine whether Lp(a) lowering reduces cardiovascular risk. The results of these studies have the potential to transform our approach to the prevention of cardiovascular disease.

Acute Increase in Ocular Microcirculation Blood Flow Upon Cholesterol Removal. The Eyes Are the Window of the Heart

BACKGROUND

Lipoprotein apheresis acutely increases coronary microvascular blood flow. However, measurement techniques are time-consuming, costly, and invasive. The ocular vasculature may be an appropriate surrogate and an easily accessible window to investigate the microcirculation. Recent advances in ocular imaging techniques enable quick, noninvasive quantification of ocular microcirculation blood flow. The insights from these techniques represent a significant opportunity to study the short-term changes in optic disk blood flow after lipoprotein apheresis for inherited hypercholesterolemia.

METHODS

This study was performed at the Italian Reference Center for Inherited Dyslipidemias in Tuscany. The study sample was comprised of 22 patients with inherited hypercholesterolemia who were previously studied for coronary microcirculation. Laser speckle flowgraphy (LSFG) was used to measure optic disk blood flow before and after lipoprotein apheresis. The main outcomes measures were average tissue blood flow (referred to as mean tissue) and arteriolar/venular average blood flow (referred to as mean vessel). Eyes were divided into 2 groups based on pre-lipoprotein apheresis optic disk blood flow values. P < .05 was considered statistically significant.

RESULTS

After each lipoprotein apheresis treatment resulting in the reduction of plasma lipids, there was a concurrent increase in all optic disk microcirculatory parameters. The increase was statistically significant in eyes with lower pre-apheresis optic disk blood flow values (mean tissue +7.0%, P < .005; mean vessel +7.2%, P < .05).

CONCLUSIONS

A single lipoprotein apheresis session resulted in a statistically significant short-term increase in optic disk blood flow. These findings together with previous coronary microcirculation data suggest a similar ocular and coronary blood flow response to lipoprotein apheresis. Ocular microcirculation may represent a versatile biomarker for evaluating systemic microcirculatory health, including coronary microcirculation. Hence, it is plausible that plasma lipoprotein levels may influence optic disk blood flow.

Lipoprotein(a) and Cardiovascular Disease in Chinese Population: A Beijing Heart Society Expert Scientific Statement

Elevated concentration of lipoprotein(a) [Lp(a)] is an independent risk factor for atherosclerotic cardiovascular disease, including coronary artery disease, stroke, peripheral artery disease, and so on. Emerging data suggest that Lp(a) contributes to the increased risk for cardiovascular events even in the setting of effective reduction of plasma low-density lipoprotein cholesterol. Nevertheless, puzzling issues exist covering potential genetic factors, Lp(a) assay, possible individuals for analysis, a cutoff point of increased risk, and clinical interventions. In the Chinese population, Lp(a) exhibited a distinctive prevalence and regulated various cardiovascular diseases in specific ways. Hence, it is valuable to clarify the role of Lp(a) in cardiovascular diseases and explore prevention and control measures for the increase in Lp(a) prevalence in the Chinese population. This Beijing Heart Society experts' scientific statement will present the detailed knowledge concerning Lp(a)-related studies combined with Chinese population observations to provide the key points of reference.

Health-related quality of life in homozygous familial hypercholesterolemia: A systematic review and meta-analysis

BACKGROUND

Homozygous familial hypercholesterolemia (HoFH) is a rare genetic disease characterized by extreme elevations of low-density lipoprotein cholesterol (LDL-C) and extremely premature atherosclerotic cardiovascular disease. To date, impacts of HoFH and its treatment on the psychosocial wellbeing of patients have been poorly characterized.

OBJECTIVES

We performed a systematic review of the association between HoFH and health-related quality of life (HRQL).

METHODS

This review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) consensus guidelines. We searched MEDLINE, Embase, The Cochrane Controlled Register of Trials (CENTRAL), Pubmed, Scopus, AfricaWide (via EBSCO), and six trial registries and grey-literature databases from inception to May 2021 for published English-language literature examining HRQL and its determinants in HoFH. Studies were eligible if they included patients with confirmed HoFH and evaluated HRQL using validated tools. We performed a narrative synthesis of qualitative findings from included studies and, where data permitted, random-effects meta-analysis reporting standardized mean differences (SMD) and 95% confidence intervals (CIs).

RESULTS

Our review identified seven eligible studies examining HRQL in HoFH participants. Pooling data from two included studies, we found that relative to the general population, HoFH patients demonstrated significantly poorer HRQL in multiple dimensions of the 36-item Short-Form Health Survey (SF-36) with lower scores in physical functioning (SMD -0.37; 95% CI: -0.60, -0.15), role limitations due to physical health (SMD -0.63; 95% CI: -1.24, -0.02), social functioning (SMD -0.61; 95% CI: -1.19, -0.03), bodily pain (SMD -0.24; 95% CI: -0.46, -0.01), and general health (SMD -1.55; 95% CI: -1.80, -1.31). No differences were observed in domains of energy and vitality, mental health and emotional well-being, or role limitations due to emotional problems. Patients suffered high treatment burdens related to lipoprotein apheresis that compromised educational attainment and employment. However, few patients received psychological support in navigating their treatment challenges. No studies evaluated the association of HoFH with incident anxiety, depression, or other psychopathology.

CONCLUSIONS

Limited data are available on quality of life for patients with HoFH. The available data suggest that these patients may suffer disease-related impairments in quality of life. Future work should aim to elucidate relationships between HoFH and mental health outcomes and develop interventions to improve quality of life in this population.

Hypertriglyceridaemia: contemporary management of a neglected cardiovascular risk factor

Hypertriglyceridaemia represents one of the most prevalent lipid abnormalities, however it is often eclipsed by focus on LDL cholesterol and is frequently overlooked by clinicians, despite it being an important cardiovascular risk factor. For most patients, hypertriglyceridaemia arises from a combination of environmental factors and multiple genetic variations with small effects. Even in cases with apparent familial clustering of hypertriglyceridaemia, a monogenetic cause is rarely identified. Common secondary causes include obesity, uncontrolled diabetes, alcohol, and various commonly used drugs. Correction of these factors, along with lifestyle optimisation, should be prioritised prior to commencing medication. The goal of drug treatment is to reduce the risk of cardiovascular disease in those with moderate hypertriglyceridaemia and the risk of pancreatitis in those with severe hypertriglyceridaemia. Recent and ongoing trials demonstrate the important role of triglycerides (TG) in determining residual risk in patients with cardiovascular disease (CVD) already established on statin therapy. Novel and emerging data on omega-3 fatty acids (high-dose icosapent ethyl) and the selective PPAR modulator pemafibrate are eagerly awaited and may provide further clarity for clinicians in determining which patients will benefit from TG lowering and help inform clinical guidelines. There are numerous novel therapies on the horizon that reduce TG by decreasing the activity of proteins that inhibit lipoprotein lipase such as apolipoprotein C-III (including Volanesorsen which was recently approved in Germany) and ANGPTL 3/4 which may offer promise for the future.

The Riskier Lipid: What Is on the HORIZON for Lipoprotein (a) and Should There Be Lp(a) Screening for All?

PURPOSE OF REVIEW

Despite widespread targeting of cardiovascular risk factors, many patients continue to experience clinical events. This residual risk has stimulated efforts to develop novel therapeutic approaches to target additional factors underscoring cardiovascular disease. This review aimed to summarize existing evidence supporting targeting of Lp(a) as a novel cardioprotective strategy.

RECENT FINDINGS

Increasing evidence has implicated lipoprotein (a) [Lp(a)] in the pathogenesis of both atherosclerotic and calcific aortic valve disease. Therapeutic advances have produced novel agents that selectively lower Lp(a) levels, which have now progressed to evaluate their impact on cardiovascular events in large clinical outcome trials. Evidence continues to accumulate suggesting that targeting Lp(a) may be effective in reducing cardiovascular risk. With advances in Lp(a) targeted therapeutics, clinical trials now have the opportunity to determine whether this strategy will be effective for high-risk patients.

Cardiovascular events in patients with familial hypercholesterolemia and hyperlipoproteinaemia (a): Indications for lipoprotein apheresis in Poland

BACKGROUND

Lipoprotein apheresis (LA) is a safe method of reducing atherogenic lipoproteins and improving cardiovascular (CV) outcomes. We aimed to assess the reductions in low-density lipoprotein cholesterol (LDL-C) and lipoprotein (a) [Lp(a)] levels in patients undergoing regular LA therapy and to evaluate its influence on the incidence rate of adverse cardiac and vascular events (ACVE) and major adverse cardiac events (MACE).

METHODS

A longitudinal study in Poland evaluated the prospective and retrospective observational data of 23 patients with hyperlipoproteinaemia (a) [hyper-Lp(a)] and familial hypercholesterolemia (FH), undergoing 1014 LA sessions between 2013 and 2020. Their pre- and post-apheresis LDL-C and Lp(a) levels were assessed to calculate the acute percent reductions. The time period used to evaluate annual rates of ACVE and MACE before and after initiation of LA was matched in each patient.

RESULTS

The pre-apheresis LDL-C and Lp(a) concentrations were 155 (107-228) (mg/dL) (median and interquartile range) and 0.56 (0.14-1.37) (g/L), respectively. LA therapy resulted in a reduction of LDL-C to 50 (30-73.5) (mg/dL) and of Lp(a) to 0.13 (0.05-0.34) (g/L), representing a percent reduction of 70.0% and 72.7% for LDL-C and Lp(a), respectively. We found a significant reduction in the annual rate of ACVE (0.365[0.0-0.585] vs (0.0[0.0-0.265]; P = .047) and MACE (0.365[0.0-0.585] vs 0.0[0.0-0.265]; P = .031).

CONCLUSIONS

The findings of our study indicate that LA treatment in patients with hyperlipoproteinaemia (a) and FH on maximally tolerated lipid lowering therapies leads to a substantial reduction in LDL-C and Lp(a) concentrations and lowers CV event rates in Polish patients.

Lipid-Lowering Agents

Several new or emerging drugs for dyslipidemia owe their existence, in part, to human genetic evidence, such as observations in families with rare genetic disorders or in Mendelian randomization studies. Much effort has been directed to agents that reduce LDL (low-density lipoprotein) cholesterol, triglyceride, and Lp[a] (lipoprotein[a]), with some sustained programs on agents to raise HDL (high-density lipoprotein) cholesterol. Lomitapide, mipomersen, AAV8.TBG.hLDLR, inclisiran, bempedoic acid, and gemcabene primarily target LDL cholesterol. Alipogene tiparvovec, pradigastat, and volanesorsen primarily target elevated triglycerides, whereas evinacumab and IONIS-ANGPTL3-L_Rx target both LDL cholesterol and triglyceride. IONIS-APO(a)-L_Rx targets Lp(a).

Lipoprotein(a) – Link between Atherogenesis and Thrombosis

Lipoprotein(a) – Lp(a) – is an independent risk factor for cardiovascular disease (CVD). Indeed, individuals with plasma concentrations of Lp(a) > 200 mg/l carry an increased risk of developing CVD. Circulating levels of Lp(a) are remarkably resistant to common lipid lowering therapies, currently available treatment for reduction of Lp(a) is plasma apheresis, which is costly and labour intensive. The Lp(a) molecule is composed of two parts: LDL/apoB-100 core and glycoprotein, apolipoprotein(a) – Apo(a), both of them can interact with components of the coagulation cascade, inflammatory pathways and blood vessel cells (smooth muscle cells and endothelial cells). Therefore, it is very important to determine the molecular pathways by which Lp(a) affect the vascular system in order to design therapeutics for targeting the Lp(a) cellular effects. This paper summarises the cellular effects and molecular mechanisms by which Lp(a) participate in atherogenesis, thrombogenesis, inflammation and development of cardiovascular diseases.

NHLBI Working Group Recommendations to Reduce Lipoprotein(a)-Mediated Risk of Cardiovascular Disease and Aortic Stenosis

Pathophysiological, epidemiological, and genetic studies provide strong evidence that lipoprotein(a) [Lp(a)] is a causal mediator of cardiovascular disease (CVD) and calcific aortic valve disease (CAVD). Specific therapies to address Lp(a)-mediated CVD and CAVD are in clinical development. Due to knowledge gaps, the National Heart, Lung, and Blood Institute organized a working group that identified challenges in fully understanding the role of Lp(a) in CVD/CAVD. These included the lack of research funding, inadequate experimental models, lack of globally standardized Lp(a) assays, and inadequate understanding of the mechanisms underlying current drug therapies on Lp(a) levels. Specific recommendations were provided to facilitate basic, mechanistic, preclinical, and clinical research on Lp(a); foster collaborative research and resource sharing; leverage expertise of different groups and centers with complementary skills; and use existing National Heart, Lung, and Blood Institute resources. Concerted efforts to understand Lp(a) pathophysiology, together with diagnostic and therapeutic advances, are required to reduce Lp(a)-mediated risk of CVD and CAVD.

Lipoprotein(a): An independent, genetic, and causal factor for cardiovascular disease and acute myocardial infarction

Lipoprotein(a) [Lp(a)] is a circulating lipoprotein, and its level is largely determined by variation in the Lp(a) gene (LPA) locus encoding apo(a). Genetic variation in the LPA gene that increases Lp(a) level also increases coronary artery disease (CAD) risk, suggesting that Lp(a) is a causal factor for CAD risk. Lp(a) is the preferential lipoprotein carrier for oxidized phospholipids (OxPL), a proatherogenic and proinflammatory biomarker. Lp(a) adversely affects endothelial function, inflammation, oxidative stress, fibrinolysis, and plaque stability, leading to accelerated atherothrombosis and premature CAD. The INTER-HEART Study has established the usefulness of Lp(a) in assessing the risk of acute myocardial infarction in ethnically diverse populations with South Asians having the highest risk and population attributable risk. The 2018 Cholesterol Clinical Practice Guideline have recognized elevated Lp(a) as an atherosclerotic cardiovascular disease risk enhancer for initiating or intensifying statin therapy.

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.

Familial Hypercholesterolemia: New Horizons for Diagnosis and Effective Management

Familial hypercholesterolemia (FH) is a common genetic cause of premature cardiovascular disease (CVD). The reported prevalence rates for both heterozygous FH (HeFH) and homozygous FH (HoFH) vary significantly, and this can be attributed, at least in part, to the variable diagnostic criteria used across different populations. Due to lack of consistent data, new global registries and unified guidelines are being formed, which are expected to advance current knowledge and improve the care of FH patients. This review presents a comprehensive overview of the pathophysiology, epidemiology, manifestations, and pharmacological treatment of FH, whilst summarizing the up-to-date relevant recommendations and guidelines. Ongoing research in FH seems promising and novel therapies are expected to be introduced in clinical practice in order to compliment or even substitute current treatment options, aiming for better lipid-lowering effects, fewer side effects, and improved clinical outcomes.

Lipoprotein apheresis affects lipoprotein particle subclasses more efficiently compared to the PCSK9 inhibitor evolocumab, a pilot study

Lipoprotein apheresis and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors are last therapeutic resorts in patients with familial hypercholesterolemia (FH). We explored changes in lipoprotein subclasses and high-density lipoprotein (HDL) function when changing treatment from lipoprotein apheresis to PCSK9 inhibition. We measured the levels of low-density lipoprotein (LDL) and HDL particle subclasses, serum amyloid A1 (SAA1), paraoxonase-1 (PON1) activity and cholesterol efflux capacity (CEC) in three heterozygous FH patients. Concentrations of all LDL particle subclasses were reduced during apheresis (large 68.0 ± 17.5 to 16.3 ± 2.1 mg/dL, (p = 0.03), intermediate 38.3 ± 0.6 to 5.0 ± 3.5 mg/dL (p = 0.004) and small 5.0 ± 2.6 to 0.2 ± 0.1 mg/dL (p = 0.08)). There were non-significant reductions in the LDL subclasses during evolocumab treatment. There were non-significant reductions in subclasses of HDL particles during apheresis, and no changes during evolocumab treatment. CEC was unchanged throughout the study, while the SAA1/PON1 ratio was unchanged during apheresis but decreased during evolocumab treatment. In conclusion, there were significant reductions in large and intermediate size LDL particles during apheresis, and a non-significant reduction in small LDL particles. There were only non-significant reductions in the LDL subclasses during evolocumab treatment.

A Test in Context: Lipoprotein(a): Diagnosis, Prognosis, Controversies, and Emerging Therapies

Evidence that elevated lipoprotein(a) (Lp[a]) levels contribute to cardiovascular disease (CVD) and calcific aortic valve stenosis (CAVS) is substantial. Development of isoform-independent assays, in concert with genetic, epidemiological, translational, and pathophysiological insights, have established Lp(a) as an independent, genetic, and likely causal risk factor for CVD and CAVS. These observations are consistent across a broad spectrum of patients, risk factors, and concomitant therapies, including patients with low-density lipoprotein cholesterol <70 mg/dl. Statins tend to increase Lp(a) levels, possibly contributing to the "residual risk" noted in outcomes trials and at the bedside. Recently approved proprotein convertase subtilisin/kexin-type 9 inhibitors and mipomersen lower Lp(a) 20% to 30%, and emerging RNA-targeted therapies lower Lp(a) >80%. These approaches will allow testing of the "Lp(a) hypothesis" in clinical trials. This review summarizes the current landscape of Lp(a), discusses controversies, and reviews emerging therapies to reduce plasma Lp(a) levels to decrease risk of CVD and CAVS.

Serum lipoprotein(a) level as long-term predictor of cardiovascular mortality in a large sample of subjects in primary cardiovascular prevention: data from the Brisighella Heart Study

BACKGROUND

High lipoprotein(a) [Lp(a)] levels have been re-evaluated as an independent risk factor for atherosclerotic vascular diseases.

METHODS

We assessed whether serum Lp(a) levels can significantly influence long-term survival in subjects with an equal general cardiovascular (CV) risk profile. We prospectively evaluated a sample of 1215 adult subjects from the Brisighella Heart Study cohort (M: 608; F: 607; aged 40-69) who had no cardiovascular disease at enrolment. According to the CUORE project risk-charts (Italian-specific risk-charts), individuals were stratified into a low-(n=865), an intermediate-(n=275) and a high-(n=75) cardiovascular risk groups. Kaplan-Meier 25-year survival analysis was carried out examining apart each class of risk and the log-rank statistic was used to estimate, when statistically possible, the survival time of the subjects stratified into quartiles of Lp(a).

RESULTS

Subjects at high and intermediate CV risk aged 56-69years (regardless of gender) and women aged 40-55years with a low CV risk profile who had lower Lp(a) levels showed a significant benefit on CV mortality (P<0.05 always) and, indicatively, on the estimated survival time (even P<0.05). The ROC curves constructing for each CV risk group using Lp(a) as test-variable and death as state-variable identified serum Lp(a) as an independent long-term CV mortality prognosticator for subjects at high CV risk (AUC=0.63, 95%CI [0.50-0.76], P=0.049) and women with an intermediate CV risk profile (AUC=0.7, 95%CI [0.52-0.79], P=0.034).

CONCLUSIONS

In the light of our finding and at the best of the previous knowledge, dosing Lp(a) is confirmed as important in subjects at high or medium risk (even if in primary prevention for CV diseases), especially in women.