Design and rationale of the EBBINGHAUS trial: A phase 3, double-blind, placebo-controlled, multicenter study to assess the effect of evolocumab on cognitive function in patients with clinically evident cardiovascular disease and receiving statin background lipid-lowering therapy-A cognitive study of patients enrolled in the FOURIER trial

PCSK-9 inhibitors: a new direction for the future treatment of ischemic stroke

Ischemic stroke, the most prevalent and serious manifestation of cerebrovascular disease, is the main cause of neurological problems that require hospitalization, resulting in disability and death worldwide. Currently, clinical practice focuses on the effective management of blood lipids as a crucial approach to preventing and treating ischemic stroke. In recent years, a great breakthrough in ischemic stroke treatment has been witnessed with the emergence and use of a novel lipid-lowering medication, Proprotein convertase subtilisin kexin type 9 (PCSK9) inhibitor. And its remarkable potential for reducing the occurrence of ischemic stroke is being acknowledged. This article aims to provide a comprehensive review, encompassing the association between PCSK9 and the heightened risk of ischemic stroke, the mechanisms, and the extensive evidence supporting the proven efficacy of PCSK9 inhibitors in clinical practice. Through this present study, we can gain deeper insights into the utilization and impact of PCSK9 inhibitors in treating ischemic stroke.

Targeting proprotein convertase subtilisin/kexin type 9 (PCSK9): from bench to bedside

Proprotein convertase subtilisin/kexin type 9 (PCSK9) has evolved as a pivotal enzyme in lipid metabolism and a revolutionary therapeutic target for hypercholesterolemia and its related cardiovascular diseases (CVD). This comprehensive review delineates the intricate roles and wide-ranging implications of PCSK9, extending beyond CVD to emphasize its significance in diverse physiological and pathological states, including liver diseases, infectious diseases, autoimmune disorders, and notably, cancer. Our exploration offers insights into the interaction between PCSK9 and low-density lipoprotein receptors (LDLRs), elucidating its substantial impact on cholesterol homeostasis and cardiovascular health. It also details the evolution of PCSK9-targeted therapies, translating foundational bench discoveries into bedside applications for optimized patient care. The advent and clinical approval of innovative PCSK9 inhibitory therapies (PCSK9-iTs), including three monoclonal antibodies (Evolocumab, Alirocumab, and Tafolecimab) and one small interfering RNA (siRNA, Inclisiran), have marked a significant breakthrough in cardiovascular medicine. These therapies have demonstrated unparalleled efficacy in mitigating hypercholesterolemia, reducing cardiovascular risks, and have showcased profound value in clinical applications, offering novel therapeutic avenues and a promising future in personalized medicine for cardiovascular disorders. Furthermore, emerging research, inclusive of our findings, unveils PCSK9's potential role as a pivotal indicator for cancer prognosis and its prospective application as a transformative target for cancer treatment. This review also highlights PCSK9's aberrant expression in various cancer forms, its association with cancer prognosis, and its crucial roles in carcinogenesis and cancer immunity. In conclusion, this synthesized review integrates existing knowledge and novel insights on PCSK9, providing a holistic perspective on its transformative impact in reshaping therapeutic paradigms across various disorders. It emphasizes the clinical value and effect of PCSK9-iT, underscoring its potential in advancing the landscape of biomedical research and its capabilities in heralding new eras in personalized medicine.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) in the central nervous system

The gene encoding proprotein convertase subtilisin/kexin type 9 (PCSK9) and its protein product have been widely studied for their role in cholesterol and lipid metabolism. PCSK9 increases the rate of metabolic degradation of low-density lipoprotein receptors, preventing the diffusion of low-density lipoprotein (LDL) from plasma into cells and contributes to high lipoprotein-bound cholesterol levels in the plasma. While most research has focused on the regulation and disease relevance of PCSK9 to the cardiovascular system and lipid metabolism, there is a growing body of evidence that PCSK9 plays a crucial role in pathogenic processes in other organ systems, including the central nervous system. PCSK9's impact on the brain is not yet fully understood, though several recent studies have sought to illuminate its impact on various neurodegenerative and psychiatric disorders, as well as its connection with ischemic stroke. Cerebral PCSK9 expression is low but is highly upregulated during disease states. Among others, PCSK9 is known to play a role in neurogenesis, neural cell differentiation, central LDL receptor metabolism, neural cell apoptosis, neuroinflammation, Alzheimer's Disease, Alcohol Use Disorder, and stroke. The PCSK9 gene contains several polymorphisms, including both gain-of-function and loss-of-function mutations which profoundly impact normal PCSK9 signaling and cholesterol metabolism. Gain-of-function mutations lead to persistent hypercholesterolemia and poor health outcomes, while loss-of-function mutations generally lead to hypocholesterolemia and may serve as a protective factor against diseases of the liver, cardiovascular system, and central nervous system. Recent genomic studies have sought to identify the end-organ effects of such mutations and continue to identify evidence of a much broader role for PCSK9 in extrahepatic organ systems. Despite this, there remain large gaps in our understanding of PCSK9, its regulation, and its effects on disease risk outside the liver. This review, which incorporates data from a wide range of scientific disciplines and experimental paradigms, is intended to describe PCSK9's role in the central nervous system as it relates to cerebral disease and neuropsychiatric disorders, and to examine the clinical potential of PCSK9 inhibitors and genetic variation in the PCSK9 gene on disease outcomes, including neurological and neuropsychiatric disease.

Cost-Effectiveness of Evolocumab in Adult Patients with Atherosclerotic Cardiovascular Disease from Chinese Healthcare Perspective

INTRODUCTION

To assess the cost-effectiveness of evolocumab with statins versus placebo combined with statins in the treatment of adult patients with atherosclerotic cardiovascular disease (ASCVD) and low-density lipoprotein cholesterol (LDL-C) levels > 70 mg/dl after the maximum tolerable dose of statin therapy in China.

METHODS

A Markov model, based on data from the FOURIER trial, claims databases, and published literature, was used to compare the health outcomes of the two therapies from the perspective of Chinese healthcare system. The time horizon in the model was a lifetime, the cycle length was a year, and the discount rate was 5%. The output indicators of the model included direct medical costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs). Sensitivity analyses were conducted on critical parameters such as cost, utility, and incidence of cardiovascular events to evaluate the effect of uncertainty in parameters and the robustness of the model.

RESULTS

In Chinese adult patients with ASCVD and LDL-C levels > 70 mg/dl, evolocumab was associated with incremental QALYs of 1.25 and incremental costs of 18,714 CNY versus placebo, both with a statin therapy, resulting in an ICER of 14,969 CNY/QALY gained, which was less than the willingness to pay (WTP) threshold (80,976 CNY/QALY, a capita GDP of China, 2021). The result of one-way sensitivity analysis indicated that when the effect of evolocumab on myocardial infarction (MI) rate after the first year varied, ICER changed the most. The results of probabilistic sensitivity analysis showed that the probability of evolocumab added to statins being cost-effective at a threshold of 80,976 CNY/QALY was 100%.

CONCLUSION

Compared with placebo and statin therapy combination, evolocumab added to statin therapy for adult patients with ASCVD and LDL-C > 70 mg/dl in China is cost-effective.

Comparing the Relationships of Genetically Proxied PCSK9 Inhibition With Mood Disorders, Cognition, and Dementia Between Men and Women: A Drug‐Target Mendelian Randomization Study

Background

PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitors are important therapeutic options for reducing cardiovascular disease risk; however, questions remain regarding potential differences in the neuropsychiatric impact of long‐term PCSK9 inhibition between men and women.

Methods and Results

Using PCSK9 gene single‐nucleotide polymorphisms from European ancestry–based genome‐wide association studies of low‐density lipoprotein cholesterol (N=1 320 016), circulating PCSK9 protein levels (N=10 186), tissue‐specific PCSK9 gene expression, sex‐specific genome‐wide association studies of anxiety, depression, cognition, insomnia, and dementia (ranging from 54 321 to 194 174), we used drug‐target inverse variance–weighted Mendelian randomization (MR) and complementary MR methods (MR Egger, weighted median, and weighted mode) to investigate potential neuropsychiatric consequences of genetically proxied PCSK9 inhibition in men and women. We failed to find evidence surpassing correction for multiple comparisons of relationships between genetically proxied PCSK9 inhibition and the risk for the 12 neuropsychiatric end points in either men or women. Drug‐target analyses were generally well‐powered to detect effect estimates at several hypothesized thresholds for both combined‐sex and sex‐specific end points, especially analyses using PCSK9 instruments derived from protein and expression quantitative trait loci. Further, MR estimates across complementary MR methods and additional models using genetic instruments derived from circulating PCSK9 protein levels and tissue‐specific PCSK9 expression were in alignment, strengthening causal inference.

Conclusions

Genetically proxied PCSK9 inhibition showed a neutral neuropsychiatric side effect profile with no major sex‐specific differences. Given statistical power considerations, replication with larger samples, as well as data from other ancestral populations, are necessary. These findings may have important clinical implications for lipid‐lowering drug‐prescribing practices and side effect monitoring of approved and future PCSK9 therapies.

Mendelian Randomization Study of PCSK9 and HMG-CoA Reductase Inhibition and Cognitive Function

BACKGROUND

Lipid-lowering therapy with statins and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition are effective strategies in reducing cardiovascular disease risk; however, concerns remain about potential long-term adverse neurocognitive effects.

OBJECTIVES

This genetics-based study aimed to evaluate the relationships of long-term PCSK9 inhibition and statin use on neurocognitive outcomes.

METHODS

We extracted single-nucleotide polymorphisms in 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) and PCSK9 from predominantly European ancestry-based genome-wide association studies summary-level statistics of low-density lipoprotein cholesterol and performed drug-target Mendelian randomization, proxying the potential neurocognitive impact of drug-based PCSK9 and HMGCR inhibition using a range of outcomes to capture the complex facets of cognition and dementia.

RESULTS

Using data from a combined sample of ∼740,000 participants, we observed a neutral cognitive profile related to genetic PCSK9 inhibition, with no significant effects on cognitive performance, memory performance, or cortical surface area. Conversely, we observed several adverse associations for HMGCR inhibition with lowered cognitive performance (beta: -0.082; 95% CI: -0.16 to -0.0080; P = 0.03), reaction time (beta = 0.00064; 95% CI: 0.00030-0.00098; P = 0.0002), and cortical surface area (beta = -0.18; 95% CI: -0.35 to -0.014; P = 0.03). Neither PCSK9 nor HMGCR inhibition impacted biomarkers of Alzheimer's disease progression or Lewy body dementia risk. Consistency of findings across Mendelian randomization methods accommodating different assumptions about genetic pleiotropy strengthens causal inference.

CONCLUSIONS

Using a wide range of cognitive function and dementia endpoints, we failed to find genetic evidence of an adverse PCSK9-related impact, suggesting a neutral cognitive profile. In contrast, we observed adverse neurocognitive effects related to HMGCR inhibition, which may well be outweighed by the cardiovascular benefits of statin use, but nonetheless may warrant pharmacovigilance.

Lipids, Lipid-Lowering Therapy, and Neuropathy: A Narrative Review

Statins, or 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, are the mainstay of treatment for hypercholesterolemia as they effectively reduce LDL-C levels and risk of atherosclerotic cardiovascular disease. Apart from hyperglycemia, dyslipidemia and HDL dysfunction are known risk factors for neuropathy in people with obesity and diabetes. Although there are case reports of statin-induced neuropathy, ad hoc analyses of clinical trials and observational studies have shown that statins may improve peripheral neuropathy. However, large randomized controlled trials and meta-analyses of cardiovascular outcome trials with statins and other lipid-lowering drugs have not reported on neuropathy outcomes. Because neuropathy was not a prespecified outcome in major cardiovascular trials, one cannot conclude whether statins or other lipid-lowering therapies increase or decrease the risk of neuropathy. The aim of this review was to assess if statins have beneficial or detrimental effects on neuropathy and whether there is a need for large well-powered interventional studies using objective neuropathy end points.

PoLA/CFPiP/PCS/PSLD/PSD/PSH guidelines on diagnosis and therapy of lipid disorders in Poland 2021

In Poland there are still nearly 20 million individuals with hypercholesterolaemia, most of them are unaware of their condition; that is also why only ca. 5% of patients with familial hypercholesterolaemia have been diagnosed; that is why other rare cholesterol metabolism disorders are so rarely diagnosed in Poland. Let us hope that these guidelines, being an effect of work of experts representing 6 main scientific societies, as well as the network of PoLA lipid centers being a part of the EAS lipid centers, certification of lipidologists by PoLA, or the growing number of centers for rare diseases, with a network planned by the Ministry of Health, improvements in coordinated care for patients after myocardial infarction (KOS-Zawał), reimbursement of innovative agents, as well as introduction in Poland of an effective primary prevention program, will make improvement in relation to these unmet needs in diagnostics and treatment of lipid disorders possible.

Metabolic Syndrome and Cognitive Function

PURPOSE OF REVIEW

Metabolic syndrome (MetS) is a cluster of cardiovascular disease risk factors that are related to several adverse health outcomes, including poor cognitive function. This review seeks to summarize and critically review select recent findings on the association between MetS and cognition.

RECENT FINDINGS

MetS was associated with lower domain-specific and global cognitive function in most cross-sectional studies, but findings from longitudinal studies are not consistent. The associations varied depending on age, sex, cognitive test, genetic susceptibility, and the duration of follow-up in prospective studies. MetS was associated with a higher risk of mild cognitive impairment (MCI) and progression from MCI to dementia, particularly vascular dementia. Among MetS components, high blood pressure, high waist circumference, and hyperglycemia were the strongest predictors of cognitive function. MetS is associated with higher risk of cognitive impairment. Research is needed on how preventing or treating MetS affects cognition.

Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) in the Brain and Relevance for Neuropsychiatric Disorders

Proprotein convertase subtilisin/kexin type 9 (PCSK9) has long been studied in the liver due to its regulation of plasma low-density lipoprotein cholesterol (LDL-C) and its causal role in familial hypercholesterolemia. Although PCSK9 was first discovered in cerebellar neurons undergoing apoptosis, its function in the central nervous system (CNS) is less clear. PCSK9 has been shown to be involved in neuronal differentiation, LDL receptor family metabolism, apoptosis, and inflammation in the brain, but in vitro and in vivo studies offer contradictory findings. PCSK9 expression in the adult brain is low but is highly upregulated during disease states. Cerebral spinal fluid (CSF) PCSK9 concentrations are correlated with neural tube defects and neurodegenerative diseases in human patients. Epigenetic studies reveal that chronic alcohol use may modulate methylation of the PCSK9 gene and genetic studies show that patients with gain-of-function PCSK9 variants have higher LDL-C and an increased risk of ischemic stroke. Early safety studies of the PCSK9 inhibitors evolocumab and alirocumab, used to treat hypercholesterolemia, hinted that PCSK9 inhibition may negatively impact cognition but more recent, longer-term clinical trials found no adverse neurocognitive events. The purpose of this review is to elucidate the role of PCSK9 in the brain, particularly its role in disease pathogenesis.

Egyptian Association of Vascular Biology and Atherosclerosis (EAVA) consensus on the usage of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors

Background

The current expert view of the PCSK9 inhibitors’ use in Egypt is still ambiguous.

Main body

Hyperlipidemia is an important, if not the most important, risk factor for the occurrence of atherosclerosis worldwide. Egypt is the most populous country in the Middle East and North Africa and has > 15% of the cardiovascular deaths in the region. The burden of dyslipidemia as seen in the recently published CardioRisk project conducted throughout Egypt shows a high prevalence of dyslipidemia as a risk factor that is still reaching up to 71% in female participants. Reaching the targets for LDL lowering, and thus control of hyperlipidemia, is quite often very difficult especially with the update of the last ESC guidelines. With the advent of PCSK9 inhibitors, the control rate of patients, reduction of cardiac major adverse events, and mortality have been improved. However, Egypt is not considered a rich country on the grounds of annual income, and this raises a concern on which patients would benefit from these expensive medications. Revising the randomized control trials, we analyzed the data that would enable us to control LDL in those patients, at risk, to obtain simple clear indications for the use of these rather expensive medications.

Conclusion

We recommend the use of PCSK9 inhibitors in addition to statins ± ezetimibe in patients with ASCVD, by definition at very high risk; patients with ASCVD at very high risk who do not tolerate appropriate doses of at least three statins; and familial hypercholesterolaemia patients with clinically diagnosed ASCVD, at very high cardiovascular risk.

PCSK9 inhibitors: clinical evidence and implementation

The gene encoding PCSK9 was first identified and linked to the phenotype of familial hypercholesterolaemia approximately 15 years ago. Soon after, studies uncovered the role of PCSK9 in the regulation of LDL-receptor recycling and identified loss-of-function variants of PCSK9 that were associated with low circulating levels of LDL cholesterol (LDL-C) and a reduced risk of coronary artery disease. With amazing rapidity, monoclonal antibodies against PCSK9 were developed and studied in large clinical programmes. These PCSK9 inhibitors lowered plasma LDL-C levels by approximately 60%, even in patients already receiving maximum-dose statin therapy. In the past year, three cardiovascular outcome trials were completed and showed that PCSK9 inhibitors significantly reduce the risk of major vascular events. Reassuringly, this benefit comes with no major offsetting adverse events, such as an excess of myalgias, elevation of hepatic aminotransferases levels in the plasma, incident diabetes mellitus or neurocognitive adverse events. The clinical benefit of PCSK9 inhibitors seen in these trials occurred in the setting of reducing LDL-C levels to unprecedentedly low levels, suggesting that more aggressive LDL-C targets should be adopted. New technologies to inhibit PCSK9 are now being harnessed and might further revolutionize our treatment of dyslipidaemia.

A Review of PCSK9 Inhibitors and their Effects on Cardiovascular Diseases

BACKGROUND

Cardiovascular diseases remain the leading cause of morbidity and mortality in the world, with elevated Low-Density Lipoprotein-Cholesterol (LDL-C) levels as the major risk factor. Lower levels of LDL-C can effectively reduce the risk of cardiovascular diseases. Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays an important role in regulating the degradation of hepatic LDL receptors that remove LDL-C from the circulation. PCSK9 inhibitors are a new class of agents that are becoming increasingly important in the treatment to reduce LDL-C levels. Two PCSK9 inhibitors, alirocumab and evolocumab, have been approved to treat hypercholesterolemia and are available in the United States and the European Union. Through the inhibition of PCSK9 and increased recycling of LDL receptors, serum LDL-C levels can be significantly reduced.

OBJECTIVE

This review will describe the chemistry, pharmacokinetics, and pharmacodynamics of PCSK9 inhibitors and their clinical effects.

Large-Scale Phenome-Wide Association Study of PCSK9 Variants Demonstrates Protection Against Ischemic Stroke

BACKGROUND

PCSK9 inhibition is a potent new therapy for hypercholesterolemia and cardiovascular disease. Although short-term clinical trial results have not demonstrated major adverse effects, long-term data will not be available for some time. Genetic studies in large biobanks offer a unique opportunity to predict drug effects and provide context for the evaluation of future clinical trial outcomes.

METHODS

We tested the association of the PCSK9 missense variant rs11591147 with predefined phenotypes and phenome-wide, in 337 536 individuals of British ancestry in the UK Biobank, with independent discovery and replication. Using a Bayesian statistical method, we leveraged phenotype correlations to evaluate the phenome-wide impact of PCSK9 inhibition with higher power at a finer resolution.

RESULTS

The T allele of rs11591147 showed a protective effect on hyperlipidemia (odds ratio, 0.63±0.04; P=2.32×10^-38), coronary heart disease (odds ratio, 0.73±0.09; P=1.05×10^-6), and ischemic stroke (odds ratio, 0.61±0.18; P=2.40×10^-3) and was associated with increased type 2 diabetes mellitus risk adjusted for lipid-lowering medication status (odds ratio, 1.24±0.10; P=1.98×10^-7). We did not observe associations with cataracts, heart failure, atrial fibrillation, and cognitive dysfunction. Leveraging phenotype correlations, we observed evidence of a protective association with cerebral infarction and vascular occlusion. These results explore the effects of direct PCSK9 inhibition; off-target effects cannot be predicted using this approach.

CONCLUSIONS

This result represents the first genetic evidence in a large cohort for the protective effect of PCSK9 inhibition on ischemic stroke and corroborates exploratory evidence from clinical trials. PCSK9 inhibition was not associated with variables other than those related to LDL (low-density lipoprotein) cholesterol, atherosclerosis, and type 2 diabetes mellitus, suggesting that other effects are either small or absent.

Long-term Low-Density Lipoprotein Cholesterol-Lowering Efficacy, Persistence, and Safety of Evolocumab in Treatment of Hypercholesterolemia: Results Up to 4 Years From the Open-Label OSLER-1 Extension Study

Importance

The Open-Label Study of Long-term Evaluation Against LDL-C (OSLER-1) evaluated the durability of long-term efficacy and safety during long-term therapy with evolocumab, a monoclonal antibody against proprotein convertase subtilisin/kexin type 9 (PCSK9).

Objective

To determine whether LDL-C level reductions with evolocumab persist across different populations. Secondary objectives included assessment of adverse events, antidrug antibodies, and factors contributing to treatment discontinuation.

Design, Setting, and Participants

This ongoing, randomized open-label extension trial (OSLER-1) was conducted at 192 sites in 18 countries. A total of 1324 of 1666 patients randomized into 1 of 5 12-week double-blind phase 2 parent studies completed a parent study and chose to participate in OSLER-1; 1255 received 1 or more evolocumab doses. As of August 2016, 812 of 1324 (61%) had 208 weeks of follow-up. This current study was conducted from October 2011 to August 2016, with a data cutoff of August 26, 2016.

Interventions

During year 1, patients were randomized to evolocumab, 420 mg, plus standard of care (SOC) or SOC alone. After year 1, all patients continuing the study received evolocumab, 420 mg, plus SOC.

Main Outcomes and Measures

Lipids, safety, and tolerability every 12 weeks. A multivariate model identified factors associated with discontinuation of evolocumab.

Results

At parent study baseline, the mean (SD) age of the population was 57.1 (11.6) years, with 52.9% being women. The median LDL-C level was 133 mg/dL (to convert to millimoles per liter, multiply by 0.0259). After 52 weeks, evolocumab plus SOC was associated with a significant reduction in LDL-C level by 61% (95% CI, -63% to -60%) vs 2% (95% CI, -5% to -0.2%) with SOC alone (P < .001). At approximately 2, 3, and 4 years of study follow-up, the median LDL-C level was reduced by 59% (95% CI, -60% to -57%), 59% (95% CI, -61% to -58%), and 57% (95% CI, -59% to -55%), respectively, from parent study baseline. For patients receiving statin therapy unchanged from baseline, at week 208, the median LDL-C level reduction was 58%. No neutralizing antibodies to evolocumab were detected. The annualized incidence of new-onset diabetes was 4% in the SOC alone group and, adjusting for duration of evolocumab exposure, 2.8% in the evolocumab plus SOC group. Neurocognitive event rates were 0% (SOC alone) and 0.4% (evolocumab plus SOC). A total of 79% of patients persisted with evolocumab treatment, with a mean exposure duration of 44 months.

Conclusions and Relevance

In the longest clinical trial exposure to a PCSK9 inhibitor to date, evolocumab produced sustained reductions in LDL-C levels. The annual frequency of adverse events did not occur more frequently with cumulative exposure during open-label observation.

Trial Registration

clinicaltrials.gov Identifier: NCT01439880.

Proprotein Convertase Subtilisin/Kexin Type 9, Brain Cholesterol Homeostasis and Potential Implication for Alzheimer's Disease

Alzheimer’s disease (AD) has been associated with dysregulation of brain cholesterol homeostasis. Proprotein convertase subtilisin/kexin type 9 (PCSK9), beyond the known role in the regulation of plasma low-density lipoprotein cholesterol, was first identified in the brain with a potential involvement in brain development and apoptosis. However, its role in the central nervous system (CNS) and in AD pathogenesis is still far from being understood. While in vitro and in vivo evidence led to controversial results, genetic studies apparently did not find an association between PCSK9 loss of function mutations and AD risk or prevalence. In addition, a potential impairment of cognitive performances by the treatment with the PCSK9 inhibitors, alirocumab and evolocumab, have been excluded, although ongoing studies with longer follow-up will provide further insights. PCSK9 is able to affect the expression of neuronal receptors involved in cholesterol homeostasis and neuroinflammation, and higher PCSK9 concentrations have been found in the cerebrospinal fluid (CSF) of AD patients. In this review article, we critically examined the science of PCSK9 with respect to its modulatory role of the mechanisms underlying the pathogenesis of AD. In addition, based on literature data, we made the hypothesis to consider brain PCSK9 as a negative modulator of brain cholesterol homeostasis and neuroinflammation and a potential pharmacological target for treatment.

The emerging role of proprotein convertase subtilisin/kexin type-9 inhibition in secondary prevention: from clinical trials to real-world experience

PURPOSE OF REVIEW

The recent advent of a highly efficacious class of low-density lipoprotein cholesterol (LDL-C) lowering agents, the proprotein convertase subtilisin/kexin type-9 (PCSK9) inhibitors, has transformed dyslipidaemia management in patients with cardiovascular disease as well as those with familial hypercholesterolemia.

RECENT FINDINGS

Recent positive results of the landmark Further Cardiovascular Outcomes Research with PCSK9 Inhibition in Subjects with Elevated Risk cardiovascular outcome trial with evolocumab as an add-on to statin therapy demonstrate further reduction of cardiovascular events. Additional safety outcomes from this large randomized trial, as well as the EBBINGHAUS substudy, allay fears of neurocognitive disorder as an adverse effect of achieving very low LDL-C levels with these agents.

SUMMARY AND IMPLICATIONS

Widespread clinical adoption of PCSK9 inhibitors will depend on the results from ongoing and planned cardiovascular efficacy and safety trials with PCSK9 inhibitors. In addition, understanding the practical challenges and barriers to usage of these injectable agents by high cardiovascular risk patients will also affect clinical adoption of this class of agents. Analysis of cost-benefit models, along with anticipated updates to practice guidelines for dyslipidaemia management are likely to strengthen the clinical utility of PCSK9 inhibitors. Importantly, the potency of this new class of agents provides a huge opportunity to extend further the 'lower LDL-C is better' hypothesis in an effort to reduce rates of cardiovascular morbidity and mortality on a population level.

Current Role of Lipoprotein Apheresis in the Treatment of High-Risk Patients

Lipoprotein apheresis (LA) is a therapeutic approach to save the lives of patients who are at an extremely high risk of developing cardiovascular events (CVE), especially after all other therapeutic options were not tolerated, or appeared not to be effective enough. Homozygous familial hypercholesterolemia represents a clear indication to start LA therapy. Another recognized indication is a severe hypercholesterolemia, which induced CVE, often in association with other risk factors. In the last years, an expressive elevation of lipoprotein(a) (Lp(a)) emerged as an indication for LA. In Germany, progress of atherosclerosis should have been documented before the permission to start LA therapy is given in these patients. Usually, all LA methods acutely decrease both LDL-C and Lp(a). However, specific columns which reduce only Lp(a) are available. Case reports and prospective observations comparing the situation before and during LA therapy clearly show a high efficiency with respect to the reduction of CVE, especially in patients with high Lp(a) levels. PCSK9 inhibitors may reduce the need for LA in patients with heterozygous or polygenetic hypercholesterolemia, but in some patients, a combination of these drugs with LA will be necessary. In the future, an antisense oligonucleotide against apolipoprotein(a) may offer an alternative therapeutic approach.

PCSK9 inhibition for LDL lowering and beyond – implications for patients with peripheral artery disease

Abstract. Low-density lipoprotein cholesterol (LDL-C) has been proven to be a causal factor of atherosclerosis and, along with other triggers like inflammation, the most frequent reason for peripheral arterial disease. Moreover, a linear correlation between LDL-C concentration and cardiovascular outcome in high-risk patients could be established during the past century. After the development of statins, numerous randomized trials have shown the superiority for LDL-C reduction and hence the decrease in cardiovascular outcomes including mortality. Over the past decades it became evident that more intense LDL-C lowering, by either the use of highly potent statin supplements or by additional cholesterol absorption inhibitor application, accounted for an even more profound cardiovascular risk reduction. Proprotein convertase subtilisin/kexin type 9 (PCSK9), a serin protease with effect on the LDL receptor cycle leading to its degradation and therefore preventing continuing LDL-C clearance from the blood, is the target of a newly developed monoclonal antibody facilitating astounding LDL-C reduction far below to what has been set as target level by recent ESC/EAS guidelines in management of dyslipidaemias. Large randomized outcome trials including subjects with PAD so far have been able to prove significant and even more intense cardiovascular risk reduction via further LDL-C debasement on top of high-intensity statin medication. Another approach for LDL-C reduction is a silencing interfering RNA muting the translation of PCSK9 intracellularly. Moreover, PCSK9 concentrations are elevated in cells involved in plaque composition, so the potency of intracellular PCSK9 inhibition and therefore prevention or reversal of plaques may provide this mechanism of action on PCSK9 with additional beneficial effects on cells involved in plaque formation. Thus, simultaneous application of statins and PCSK9 inhibitors promise to reduce cardiovascular event burden by both LDL-C reduction and pleiotropic effects of both agents.

PCSK9 Inhibitors in Hyperlipidemia: Current Status and Clinical Outlook

The clinical reality of residual risk despite statin (HMG-CoA reductase inhibitor) therapy and emergence of statin intolerance support the need to develop additional lipid-lowering strategies. Proprotein convertase subtilisin kexin type 9 (PCSK9) has received considerable attention by virtue of genetic and clinical studies that have revealed its pivotal role in the regulation of cholesterol homeostasis. Monoclonal antibodies have been developed targeting PCSK9, which have been demonstrated to produce profound low-density lipoprotein cholesterol (LDL-C) lowering when provided as monotherapy or in combination with statins. With the reports that the PCSK9 inhibitor evolocumab has a favorable impact on both plaque progression and cardiovascular outcomes, these findings begin to translate the benefits of PCSK9 inhibition from lipids to the vessel wall and ultimately to clinical outcomes. The clinical implications for the use of these agents are reviewed in this article.

PCSK9 in context: A contemporary review of an important biological target for the prevention and treatment of atherosclerotic cardiovascular disease

The identification of the critical role of proprotein convertase subtilisin/kexin type 9 (PCSK9) has rapidly led to the development of PCSK9 inhibition with monoclonal antibodies (mAbs). PCSK9 mAbs are already in limited clinical use and are the subject of major cardiovascular outcomes trials, which, if universally positive, could see much wider clinical application of these agents. Patients with familial hypercholesterolaemia are the most obvious candidates for these drugs, but other patients with elevated cardiovascular risk, statin intolerance or hyperlipoproteinaemia(a) may also benefit. PCSK9 mAbs, administered once or twice monthly, reduce LDL cholesterol levels by 50% to 70%, and appear to be safe and acceptable to patients over at least 2 years of treatment; however, treatment-emergent adverse effects are not always identified in clinical trials, as well-evidenced by statin myopathy. Inclisiran is a promising RNA-based therapy that promotes the degradation of PCSK9 mRNA transcripts and has similar efficacy to mAbs, but with a much longer duration of action. The cost-effectiveness and long-term safety of therapies targeted at inhibiting PCSK9 remain to be demonstrated if they are to be used widely in coronary prevention.

Effect of PCSK9 Inhibitors on Clinical Outcomes in Patients With Hypercholesterolemia: A Meta-Analysis of 35 Randomized Controlled Trials

BACKGROUND

We sought to examine the efficacy and safety of 2 PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitors: alirocumab and evolocumab.

METHODS AND RESULTS

We performed a systematic review and meta-analysis of randomized controlled trials comparing treatment with and without PCSK9 inhibitors; 35 randomized controlled trials comprising 45 539 patients (mean follow-up: 85.5 weeks) were included. Mean age was 61.0±2.8 years, and mean baseline low-density lipoprotein cholesterol was 106±22 mg/dL. Compared with no PCSK9 inhibitor therapy, treatment with a PCSK9 inhibitor was associated with a lower rate of myocardial infarction (2.3% versus 3.6%; odds ratio [OR]: 0.72 [95% confidence interval (CI), 0.64-0.81]; P<0.001), stroke (1.0% versus 1.4%; OR: 0.80 [95% CI, 0.67-0.96]; P=0.02), and coronary revascularization (4.2% versus 5.8%; OR: 0.78 [95% CI, 0.71-0.86]; P<0.001). Overall, no significant change was observed in all-cause mortality (OR: 0.71 [95% CI, 0.47-1.09]; P=0.12) or cardiovascular mortality (OR: 1.01 [95% CI, 0.85-1.19]; P=0.95). A significant association was observed between higher baseline low-density lipoprotein cholesterol and benefit in all-cause mortality (P=0.038). No significant change was observed in neurocognitive adverse events (OR: 1.12 [95% CI, 0.88-1.42]; P=0.37), myalgia (OR: 0.95 [95% CI, 0.75-1.20]; P=0.65), new onset or worsening of preexisting diabetes mellitus (OR: 1.05 [95% CI, 0.95-1.17]; P=0.32), and increase in levels of creatine kinase (OR: 0.84 [95% CI, 0.70-1.01]; P=0.06) or alanine or aspartate aminotransferase (OR: 0.96 [95% CI, 0.82-1.12]; P=0.61).

CONCLUSIONS

Treatment with a PCSK9 inhibitor is well tolerated and improves cardiovascular outcomes. Although no overall benefit was noted in all-cause or cardiovascular mortality, such benefit may be achievable in patients with higher baseline low-density lipoprotein cholesterol.

Clinical efficacy and safety of achieving very low LDL-cholesterol concentrations with the PCSK9 inhibitor evolocumab: a prespecified secondary analysis of the FOURIER trial

BACKGROUND

LDL cholesterol is a well established risk factor for atherosclerotic cardiovascular disease. How much one should or safely can lower this risk factor remains debated. We aimed to explore the relationship between progressively lower LDL-cholesterol concentrations achieved at 4 weeks and clinical efficacy and safety in the FOURIER trial of evolocumab, a monoclonal antibody to proprotein convertase subtilisin-kexin type 9 (PCSK9).

METHODS

In this prespecified secondary analysis of 25 982 patients from the randomised FOURIER trial, the relationship between achieved LDL-cholesterol concentration at 4 weeks and subsequent cardiovascular outcomes (primary endpoint was the composite of cardiovascular death, myocardial infarction, stroke, coronary revascularisation, or unstable angina; key secondary endpoint was the composite of cardiovascular death, myocardial infarction, or stroke) and ten prespecified safety events of interest was examined over a median of 2·2 years of follow-up. We used multivariable modelling to adjust for baseline factors associated with achieved LDL cholesterol. This trial is registered with ClinicalTrials.gov, number NCT01764633.

FINDINGS

Between Feb 8, 2013, and June 5, 2015, 27 564 patients were randomly assigned a treatment in the FOURIER study. 1025 (4%) patients did not have an LDL cholesterol measured at 4 weeks and 557 (2%) had already had a primary endpoint event or one of the ten prespecified safety events before the week-4 visit. From the remaining 25 982 patients (94% of those randomly assigned) 13 013 were assigned evolocumab and 12 969 were assigned placebo. 2669 (10%) of 25 982 patients achieved LDL-cholesterol concentrations of less than 0·5 mmol/L, 8003 (31%) patients achieved concentrations between 0·5 and less than 1·3 mmol/L, 3444 (13%) patients achieved concentrations between 1·3 and less than 1·8 mmol/L, 7471 (29%) patients achieved concentrations between 1·8 to less than 2·6 mmol/L, and 4395 (17%) patients achieved concentrations of 2·6 mmol/L or higher. There was a highly significant monotonic relationship between low LDL-cholesterol concentrations and lower risk of the primary and secondary efficacy composite endpoints extending to the bottom first percentile (LDL-cholesterol concentrations of less than 0·2 mmol/L; p=0·0012 for the primary endpoint, p=0·0001 for the secondary endpoint). Conversely, no significant association was observed between achieved LDL cholesterol and safety outcomes, either for all serious adverse events or any of the other nine prespecified safety events.

INTERPRETATION

There was a monotonic relationship between achieved LDL cholesterol and major cardiovascular outcomes down to LDL-cholesterol concentrations of less than 0·2 mmol/L. Conversely, there were no safety concerns with very low LDL-cholesterol concentrations over a median of 2·2 years. These data support further LDL-cholesterol lowering in patients with cardiovascular disease to well below current recommendations.

FUNDING

Amgen.

A safety evaluation of evolocumab

INTRODUCTION

Evolocumab is an injectable, fully human monoclonal antibody and a member of the newest class of low density lipoprotein cholesterol (LDL-C) lowering agents called proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors. The PCSK9 inhibitors are the most significant advance in lipid therapy since the introduction of the first statin 30 years ago. Areas covered: The PCSK9 monoclonal antibodies have demonstrated a consistently high LDL-C lowering efficacy with and without statins and/or other lipid lowering therapies (LLT). LDL-C levels achieved with these agents are lower than has ever been possible before. This review will focus on the overall safety of evolocumab including cognitive impairment, very low LDL-C levels, new onset diabetes and glucose abnormalities, effect on vitamin E and steroid hormones, liver and muscle abnormalities, and immunogenicity and injection site reactions. The phase II and III clinical trials had relatively low patient-years of exposure, but the open label extension studies and the recently published outcomes trial, FOURIER, will be the focus of this paper. The safety profile of evolocumab to date is remarkable and extremely encouraging as will be demonstrated. Expert opinion: The PCSK9 inhibitors will be responsible for a new era in lipid therapy that will expand our knowledge of lipid levels and cardiovascular disease (CVD) prevention with an efficacy and safety profile not previously available in clinical practice.

Effects of Evolocumab on Cardiovascular Events

BACKGROUND

Evolocumab is a potent lipid-lowering drug that decreases plasma levels of lowdensity lipoprotein cholesterol (LDL-C) by 50-60%. FOURIER is a landmark randomized trial involving 27,564 patients with established cardiovascular disease already on statins and plasma LDLC levels > 70 mg/dl.

OBJECTIVE

The main objective of FOURIER was to examine the effects of evolocumab on cardiovascular events.

RESULTS

After a mean follow-up of 2.2 years, evolocumab significantly decreased the primary endpoint (composite of cardiovascular death, myocardial infarction, stroke, hospitalization for unstable angina, or coronary revascularization) by 15% compared to placebo [hazard ratio 0.85 (95% CI, 0.79-0.92)], but no significant effect was found on mortality. The most common adverse effect of evolocumab was mild injection site reaction occurring in 2.1% of patients versus 1.6% of patients receiving placebo.

CONCLUSION

These results support the use of evolocumab as add-on therapy to statins for high cardiac- risk patients not achieving optimal goals of LDL-C. Longer-term studies are needed to further clarify the efficacy and safety of evolocumab.

Novel treatment options for the management of heterozygous familial hypercholesterolemia

INTRODUCTION

Even though statins represent the mainstay of treatment of heterozygous familial hypercholesterolemia (FH), their low-density lipoprotein cholesterol (LDL-C) lowering efficacy is finite and most patients with FH will not achieve LDL-C targets with statin monotherapy. Addition of ezetimibe with or without bile acid sequestrants will also not lead to treatment goals in many of these patients, particularly in those with established cardiovascular disease. In this selected subgroup of the FH population, proprotein convertase subtilisin-kexin type 9 (PCSK9) inhibitors provide substantial reductions in LDL-C levels, reduce cardiovascular morbidity and appear to be safe. Mipomersen, an antisense single-strand oligonucleotide that inhibits the production of apoB by binding to the mRNA that encodes the synthesis of apoB, and lomitapide, an inhibitor of microsomal triglyceride transfer protein, also reduce LDL-C levels but are currently indicated only for the management of homozygous FH. Areas covered: In the present review, the role of PCSK9 inhibitors, mipomersen and lomitapide in the management of FH is briefly discussed. Other LDL-C-lowering agents under evaluation include inclisiran, a small interference RNA molecule that induces long-term inhibition of PSCK9 synthesis, anacetrapib, a cholesterol ester-transfer protein inhibitor, ETC-1002 (bempedoic acid), an inhibitor of adenosine triphosphate citrate lyase, and gemcabene, which reduces hepatic apolipoprotein C-III mRNA. The safety and efficacy of these agents are also reviewed. Expert Commentary: Even though several novel treatment options for heterozygous FH are under development, it remains to be shown whether these treatments will also reduce cardiovascular morbidity in these high-risk patients.

Incorporation of PCSK9 inhibitors into prevention of atherosclerotic cardiovascular disease

Primary and secondary prevention of atherosclerotic cardiovascular disease (ASCVD) has become recently more complex than ever, leaving the clinicians perplexed with outdated guidelines and emerging evidence about new LDL-C lowering therapies. 2013 American College of Cardiology (ACC)/American Heart Association (AHA) guidelines have focused on high intensity statin therapy for specific groups of patients, while abandoning long established LDL-C goals, a strategy which no longer seems valid. PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitors have emerged as the add-on therapy on top of statins and/or ezetimibe for the treatment of hypercholesterolemia and ASCVD prevention. In several clinical trials, PCSK9 inhibitors have demonstrated their safety and robust LDL-C-lowering power. One completed cardiovascular (CV) outcomes trial (FOURIER; Further Cardiovascular Outcomes Research with PCSK9 Inhibitions in Subjects with Elevated Risk) has demonstrated that PCSK9 inhibition reduces rates of CV death as well as non-fatal stroke and MI, while another major CV outcome trial is under way (ODYSSEY-OUTCOMES). Several trials studying CV benefits of novel LDL-C-lowering therapies are also being conducted. Prompt revision of ACC/AHA guidelines is necessary. In the meantime, physicians need to use clinical judgment integrating the most recent evidence into their practice.

2017 Focused Update of the 2016 ACC Expert Consensus Decision Pathway on the Role of Non-Statin Therapies for LDL-Cholesterol Lowering in the Management of Atherosclerotic Cardiovascular Disease Risk: A Report of the American College of Cardiology Task Force on Expert Consensus Decision Pathways

In 2016, the American College of Cardiology published the first expert consensus decision pathway (ECDP) on the role of non-statin therapies for low-density lipoprotein (LDL)-cholesterol lowering in the management of atherosclerotic cardiovascular disease (ASCVD) risk. Since the publication of that document, additional evidence and perspectives have emerged from randomized clinical trials and other sources, particularly considering the longer-term efficacy and safety of proprotein convertase subtilisin/kexin 9 (PCSK9) inhibitors in secondary prevention of ASCVD. Most notably, the FOURIER (Further Cardiovascular Outcomes Research with PCSK9 Inhibition in Subjects with Elevated Risk) trial and SPIRE-1 and -2 (Studies of PCSK9 Inhibition and the Reduction of Vascular Events), assessing evolocumab and bococizumab, respectively, have published final results of cardiovascular outcomes trials in patients with clinical ASCVD and in a smaller number of high-risk primary prevention patients. In addition, further evidence on the types of patients most likely to benefit from the use of ezetimibe in addition to statin therapy after acute coronary syndrome has been published. Based on results from these important analyses, the ECDP writing committee judged that it would be desirable to provide a focused update to help guide clinicians more clearly on decision making regarding the use of ezetimibe and PCSK9 inhibitors in patients with clinical ASCVD with or without comorbidities. In the following summary table, changes from the 2016 ECDP to the 2017 ECDP Focused Update are highlighted, and a brief rationale is provided. The content of the full document has been changed accordingly, with more extensive and detailed guidance regarding decision making provided both in the text and in the updated algorithms. Revised recommendations are provided for patients with clinical ASCVD with or without comorbidities on statin therapy for secondary prevention. The ECDP writing committee judged that these new data did not warrant changes to the decision pathways and algorithms regarding the use of ezetimibe or PCSK9 inhibitors in primary prevention patients with LDL-C <190 mg/dL with or without diabetes mellitus or patients without ASCVD and LDL-C ≥190 mg/dL not due to secondary causes. Based on feedback and further deliberation, the ECDP writing committee down-graded recommendations regarding bile acid sequestrant use, recommending bile acid sequestrants only as optional secondary agents for consideration in patients intolerant to ezetimibe. For clarification, the writing committee has also included new information on diagnostic categories of heterozygous and homozygous familial hypercholesterolemia, based on clinical criteria with and without genetic testing. Other changes to the original document were kept to a minimum to provide consistent guidance to clinicians, unless there was a compelling reason or new evidence, in which case justification is provided.

Cognitive Function in a Randomized Trial of Evolocumab

Background Findings from clinical trials of proprotein convertase subtilisin-kexin type 9 (PCSK9) inhibitors have led to concern that these drugs or the low levels of low-density lipoprotein (LDL) cholesterol that result from their use are associated with cognitive deficits. Methods In a subgroup of patients from a randomized, placebo-controlled trial of evolocumab added to statin therapy, we prospectively assessed cognitive function using the Cambridge Neuropsychological Test Automated Battery. The primary end point was the score on the spatial working memory strategy index of executive function (scores range from 4 to 28, with lower scores indicating a more efficient use of strategy and planning). Secondary end points were the scores for working memory (scores range from 0 to 279, with lower scores indicating fewer errors), episodic memory (scores range from 0 to 70, with lower scores indicating fewer errors), and psychomotor speed (scores range from 100 to 5100 msec, with faster times representing better performance). Assessments of cognitive function were performed at baseline, week 24, yearly, and at the end of the trial. The primary analysis was a noninferiority comparison of the mean change from baseline in the score on the spatial working memory strategy index of executive function between the patients who received evolocumab and those who received placebo; the noninferiority margin was set at 20% of the standard deviation of the score in the placebo group. Results A total of 1204 patients were followed for a median of 19 months; the mean (±SD) change from baseline over time in the raw score for the spatial working memory strategy index of executive function (primary end point) was -0.21±2.62 in the evolocumab group and -0.29±2.81 in the placebo group (P<0.001 for noninferiority; P=0.85 for superiority). There were no significant between-group differences in the secondary end points of scores for working memory (change in raw score, -0.52 in the evolocumab group and -0.93 in the placebo group), episodic memory (change in raw score, -1.53 and -1.53, respectively), or psychomotor speed (change in raw score, 5.2 msec and 0.9 msec, respectively). In an exploratory analysis, there were no associations between LDL cholesterol levels and cognitive changes. Conclusions In a randomized trial involving patients who received either evolocumab or placebo in addition to statin therapy, no significant between-group difference in cognitive function was observed over a median of 19 months. (Funded by Amgen; EBBINGHAUS ClinicalTrials.gov number, NCT02207634 .).

Evolocumab for the treatment of hypercholesterolemia

INTRODUCTION

Evolocumab is a fully human monoclonal immunoglobulin G2 directed against human proprotein convertase subtilisin/kexin type 9 (PCSK9). It is administered by subcutaneous injection every 2 weeks or once monthly. Area covered: Herein, the authors discuss the rationale for inhibiting PCSK9 and describe the pharmacodynamics, pharmacokinetics and clinical trials with evolocumab. Evolocumab reduces low density lipoprotein cholesterol (LDL-C) levels by 50 to 60% in most patients with and without background treatment with statins or other lipid lowering agents. The safety profile appears satisfactory from the completed clinical studies and concerns regarding the risk of neurocognitive events have largely been dispelled. Expert opinion: The reduction of LDL-C with evolocumab to previously unattainable levels has resulted in a reduction in the composite cardiovascular event endpoint in the FOURIER trial and this is likely to impact on future lipid management guidelines. The clinical outcome data and excellent tolerability profile clearly support the use of evolocumab in patients at high cardiovascular risk, including those with heterozygous or homozygous familial hypercholesterolemia, who are unable to achieve LDL-C targets with statins with or without other lipid-lowering drugs. The high cost of evolocumab will restrict its use, however.

Key Recent Advances in Atherosclerosis Treatment with Modern Lipid-lowering Drugs: The New Frontier with PCSK9 Inhibitors

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PCSK9 Inhibitors: Treating the Right Patients in Daily Practice

PURPOSE OF REVIEW

Monoclonal antibodies that inhibit proprotein convertase subtilisin/kexin type 9 (PCSK9) have emerged as a novel approach to low-density lipoprotein cholesterol (LDL-C) lowering. The potential role of PCSK9 inhibitors in clinical practice will be reviewed.

RECENT FINDINGS

Clinical trials have demonstrated that PCSK9 inhibitors produce robust LDL-C lowering when administered either as monotherapy or in combination with statins. This provides the opportunity to achieve effective lipid lowering in familial hypercholesterolemia, patients with either established atherosclerotic cardiovascular disease or high risk primary prevention and an important opportunity to treat patients with statin intolerance. The findings from plaque imaging and patients with established atherosclerotic cardiovascular disease suggest that PCSK9 inhibition has favorable outcomes beyond improving lipid profiles, which has the opportunity to expand their use. PCSK9 inhibitors represent a new approach to achieving effective cardiovascular risk reduction in a broader number of patients. How these agents will be taken up in clinical practice remains to be determined.

Physiological and therapeutic regulation of PCSK9 activity in cardiovascular disease

Ischemic heart disease is the main cause of death worldwide and is accelerated by increased levels of low-density lipoprotein cholesterol (LDL-C). Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a potent circulating regulator of LDL-C through its ability to induce degradation of the LDL receptor (LDLR) in the lysosome of hepatocytes. Only in the last few years, a number of breakthroughs in the understanding of PCSK9 biology have been reported illustrating how PCSK9 activity is tightly regulated at several levels by factors influencing its transcription, secretion, or by extracellular inactivation and clearance. Two humanized antibodies directed against the LDLR-binding site in PCSK9 received approval by the European and US authorities and additional PCSK9 directed therapeutics are climbing up the phases of clinical trials. The first outcome data of the PCSK9 inhibitor evolocumab reported a significant reduction in the composite endpoint (cardiovascular death, myocardial infarction, or stroke) and further outcome data are awaited. Meanwhile, it became evident that PCSK9 has (patho)physiological roles in several cardiovascular cells. In this review, we summarize and discuss the recent biological and clinical data on PCSK9, the regulation of PCSK9, its extra-hepatic activities focusing on cardiovascular cells, molecular concepts to target PCSK9, and finally briefly summarize the data of recent clinical studies.

Design and rationale of the EBBINGHAUS trial: A phase 3, double-blind, placebo-controlled, multicenter study to assess the effect of evolocumab on cognitive function in patients with clinically evident cardiovascular disease and receiving statin background lipid-lowering therapy-A cognitive study of patients enrolled in the FOURIER trial

Some observational studies raised concern that statins may cause memory impairment, leading to a US Food and Drug Administration warning. Similar questions were raised regarding proprotein convertase subtilisin/kexin-type 9 inhibitors (PCSK9i) and neurocognitive function. No prospectively designed study has evaluated the relationship between long-term PCSK9i use and cognition changes. Patients with prior cardiovascular disease treated with maximally tolerated statin enrolled in FOURIER (the randomized, double-blind, placebo-controlled cardiovascular outcome study of the PCSK9i evolocumab) could participate in this prospective assessment of cognitive function (EBBINGHAUS). Key additional exclusion criteria for EBBINGHAUS were dementia, cognitive impairment, or other significant mental or neurological disorder. Cognitive testing was performed using the Cambridge Neuropsychological Test Automated Battery, a tablet-based tool assessing executive function, working memory, memory function, and psychomotor speed at baseline, weeks 24 and 48, every 48 weeks thereafter, and study end. The primary endpoint was spatial working memory strategy index of executive function (SWMSI). The primary hypothesis was that evolocumab would be noninferior to placebo in the mean change from baseline over time in SWMSI. Fifteen hundred cognitively normal patients completing the assessments provided approximately 97% power to demonstrate that the upper 95% confidence interval for the treatment difference in mean change from baseline in SWMSI over time is <20% of the SD of the mean change in the placebo group. An exploratory analysis will compare neurocognitive function in patients with post-baseline low-density lipoprotein cholesterol <25 mg/dL. EBBINGHAUS will evaluate whether the addition of evolocumab to statin therapy affects cognitive function over time in patients with stable cardiovascular disease.