Therapeutic Potential and Critical Analysis of the PCSK9 Monoclonal Antibodies Evolocumab and Alirocumab

Impact of Berberine or Berberine Combination Products on Lipoprotein, Triglyceride and Biological Safety Marker Concentrations in Patients with Hyperlipidemia: A Systematic Review and Meta-Analysis

Monoclonal antibody Proprotein Convertase Subtilisin/Kexin type 9 (PCSK9) inhibitors reduce total cholesterol (TC), low density lipoproteins (LDL), high density lipoproteins (HDL), and triglycerides (TG). We assessed the ability of berberine, a natural PCSK9 inhibitor, to reduce lipid concentrations either alone or combined with other nutraceuticals. We searched PubMed, Scopus and EMBASE from inception to September 30th, 2022 for randomized controlled trials (RCTs) assessing 8-18 wk of berberine therapy on. A total of 41 RCTs with 4,838 patients met our inclusion criteria. Berberine containing products significantly reduced TC (MD -17.42 mg/dL [95%CI: -22.91 to -11.93]), LDL (MD -14.98 mg/dL [95%CI: -20.67 to -9.28]), and TG (MD -18.67 mg/dL [95%CI: -25.82 to -11.51]) while raising HDL (MD 1.97 mg/dL [95%CI: 1.16 to 2.78]) versus control (I2 > 72% for all analyses). Products with berberine alone had less robust effects on TC (MD -12.08 mg/dL [95%CI: -21.79 to -2.37]), LDL (MD -9.26 mg/dL [95%CI: -20.31 to 1.78]), and HDL (MD 1.38 mg/dL [95%CI: -1.27 to 4.03]) but TG effects were similar (MD -17.40 mg/dL [95%CI: -32.57 to -2.23]). Berberine along with red yeast rice reduced TC (MD -19.62 mg/dL [95%CI: -28.56 to -10.68]) and LDL (MD -18.79 mg/dL [95%CI: -28.03 to -9.54]) as did combination therapy with Silybum maranium for TC (MD -31.81 mg/dL [95%CI: -59.88 to -3.73]) and LDL (MD -30.82 mg/dL [95%CI: -56.48 to -5.16]). Berberine, alone or with other nutraceuticals, can provide a modest positive impact on lipid concentrations.

PCSK9 inhibition-based therapeutic approaches: an immunotherapy perspective

Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors (PCSK9-I) are novel therapeutic tools to decrease cardiovascular risk. These agents work by lowering the low-density lipoprotein cholesterol (LDL-C) in hypercholesterolemic patients who are statin resistant/intolerant. Current clinically approved and investigational PCSK9-I act generally by blocking PCSK9 activity in the plasma or suppressing its expression or secretion by hepatocytes. The most widely investigated method is the disruption of PCSK9/LDL receptor (LDLR) interaction by fully-humanized monoclonal antibodies (mAbs), evolocumab and alirocumab, which have been approved for the therapy of hypercholesterolemia and atherosclerotic cardiovascular disease (CVD). Besides, a small interfering RNA called inclisiran, which specifically suppresses PCSK9 expression in hepatocytes, is as effective as mAbs but with administration twice a year. Because of the high costs of such therapeutic approaches, several other PCSK9-I have been surveyed, including peptide-based anti-PCSK9 vaccines and small oral anti-PCSK9 molecules, which are under investigation in preclinical and phase I clinical studies. Interestingly, anti-PCSK9 vaccination has been found to serve as a more widely feasible and more cost-effective therapeutic tool over mAb PCSK9-I for managing hypercholesterolemia. The present review will discuss LDL-lowering and cardioprotective effects of PCSK9-I, mainly immunotherapy-based inhibitors including mAbs and vaccines, in preclinical and clinical studies.

Biologics and their delivery systems: Trends in myocardial infarction

Cardiovascular disease is the leading cause of death around the world, in which myocardial infarction (MI) is a precipitating event. However, current therapies do not adequately address the multiple dysregulated systems following MI. Consequently, recent studies have developed novel biologic delivery systems to more effectively address these maladies. This review utilizes a scientometric summary of the recent literature to identify trends among biologic delivery systems designed to treat MI. Emphasis is placed on sustained or targeted release of biologics (e.g. growth factors, nucleic acids, stem cells, chemokines) from common delivery systems (e.g. microparticles, nanocarriers, injectable hydrogels, implantable patches). We also evaluate biologic delivery system trends in the entire regenerative medicine field to identify emerging approaches that may translate to the treatment of MI. Future developments include immune system targeting through soluble factor or chemokine delivery, and the development of advanced delivery systems that facilitate the synergistic delivery of biologics.

Silibinin A decreases statin‑induced PCSK9 expression in human hepatoblastoma HepG2 cells

Hypercholesterolemia is one of the major risk factors for the occurrence and development of atherosclerosis. The most common drugs used to treat hypercholesterolemia are 3‑hydroxy‑3‑methyl‑glutaryl‑CoA reductase inhibitors, known as statins. Statins induce a beneficial increase in the levels of the low density lipoprotein receptor (LDLR) and additionally upregulate proprotein convertase subtilisin/kexin type 9 (PCSK9), which leads to LDLR degradation. This process causes a negative feedback response that attenuates the lipid lowering effects of statins. Therefore, the development of PCSK9 inhibitors may increase the lipid‑lowering functions of statins. In the present study, a drug‑screening assay was developed using the human PCSK9 promoter, based on data from a dual‑luciferase reporter assay, and the efficacies of various compounds from Traditional Chinese Medicine were examined. Among the compounds examined, SIL was demonstrated to function by targeting PCSK9. It was identified that SIL treatment decreased the expression levels of PCSK9 in HepG2 cells by decreasing the activity of the PCSK9 promoter in a dose‑and time‑dependent manner. Notably, SIL antagonized the statin‑induced phosphorylation of the p38 MAPK signaling pathway. The present study suggested that SIL may be developed as a novel PCSK9 inhibitor that may increase the efficiency of statin treatment.

Molecular aspects of hypercholesterolemia treatment: current perspectives and hopes

Hypercholesterolemia is a pathological condition which has been reported in 39% of the worlds' adult population. We aimed to review molecular aspects of current and novel therapeutic approaches based on low-density lipoprotein cholesterol lowering strategies. Pathogenic mutations in the LDLR, ApoB, PCSK9 and LDLRAP genes cause deficient clearance of circulating low-density lipoprotein cholesterol particles via hepatic LDL receptor. This leads to increased plasma LDL cholesterol levels from birth, which can cause LDL depositions in the arterial walls. Ultimately, it progresses to atherosclerosis and an increased risk of premature cardiovascular diseases. Currently, statins, Ezetimibe, Bile acid sequestrants and PCSK9 inhibitors are the main therapeutic agents for the treatment of hypercholesterolemia. Moreover, novel RNA-based therapy had a strong impact on therapeutic strategies in recent decades. Additional development in understanding of the molecular basis of hypercholesterolemia will provide opportunities for the development of targeted therapy in the near future. Key Messages The most common genes involved in hypercholesterolemia are LDLR, PCSK9 and ApoB. Pharmacogenetic effects are typically constrained to pathways closely related to the pharmacodynamics and pharmacokinetics. Change in lifestyle and diet along with treatment of the underlying disease and drug therapy are the current therapeutic strategies.

The Pharmacologic Role and Clinical Utility of PCSK9 Inhibitors for the Treatment of Hypercholesterolemia

In addition to monoclonal antibodies against proprotein convertase subtilisin-kexin type 9 (PCSK9), vaccines against PCSK9 and smaller molecule inhibitors as well as RNA inhibitors of PCSK9 production have been created. The monoclonal antibodies against PCSK9 and the PCSK9 RNA inhibitors can reduce low-density lipoproteins (LDLs) by over 50%, non-high-density lipoprotein (HDL) cholesterol and triglycerides, and increasing HDL. Although effective in several homozygous familial hypercholesterolemia patient types, PCSK9 inhibitors does not work in all patient types. Outcome trials show no effects on mortality but do show reductions in atherosclerotic events such as myocardial infarctions, strokes, and need for coronary revascularization. PCSK9 inhibitors have a very attractive safety profile with no significant elevations in measures of muscle or liver damage. The current and more advanced experimental agents all require subcutaneous dosing, and injection site reactions are among the most common adverse events. Therapy for the Food and Drug Administration (FDA) approved agents is markedly expensive, and this is the primary barrier to utilization. However, it is possible to identify patients with a number needed to treat to prevent an atherosclerotic event low enough to render it cost-effective and one such factor is whether or not you require a 50% reduction in LDL in order to achieve your LDL goal.

Evolving targets for the treatment of atherosclerosis

Atherosclerosis is a progressive disease of large arteries and a leading cause of cardiovascular diseases and stroke. Chronic inflammation, aberrant immune response, and disturbances to key enzymes involved with lipid metabolism are characteristic features of atherosclerosis. Apart from targeting the derangements in lipid metabolism, therapeutic modulation to regulate chronic inflammation and the immune system response may prove to be very promising strategies in the management of atherosclerosis. In recent years, various targets have been studied for the treatment of atherosclerosis. PCSK9, a serine protease, actively targets the LDL-R and causes lysosomal degradation, which leads to excessive accumulation of LDL-C. Regulatory T cells (Tregs) and Triggering Receptor Expressed on Myeloid cells-1 (TREM-1) affects the adaptive and innate immune response, respectively, and thus, therapeutic intervention of either of these targets would directly modulate disease progression. Advanced atherosclerotic lesions are characterized by an accumulation of apoptotic cells. Cluster of differentiation-47 (CD47), an anti-phagocytic known as the "don't eat me" signaling molecule, inhibits efferocytosis, which causes accumulation of cell debris in plaque. ADAMTS and Notch signaling potentially affect the formation of neointima by modulation of extracellular matrix components such as macrophages and vascular smooth muscle cells. This review provides insights on the molecular targets for therapeutic intervention of atherosclerosis, their effect at various stages of atherosclerosis development, and the therapies that have been designed and currently being evaluated in clinical trials.

Differential Expression of PCSK9 Modulates Infection, Inflammation, and Coagulation in a Murine Model of Sepsis

INTRODUCTION

Proprotein convertase subtilisin/kexin type 9 (PCSK9) targets lipoprotein receptors for degradation, thereby reducing hepatic lipid clearance. PCSK9 inhibition reduces mortality in septic mice, presumably through increased hepatic clearance of pathogen lipids due to increased lipoprotein receptor concentrations. However, PCSK9 overexpression in vivo has not been studied in sepsis. Therefore, this study aimed to evaluate the effects of differential PCSK9 expression on systemic infection, inflammation, and coagulation in sepsis.

METHODS

Wild-type, PCSK9 knockout (KO), and transgenic (Tg) mice that overexpress PCSK9 were subjected to sham surgery or cecal ligation and puncture (CLP). Bacterial loads were measured in lungs, peritoneal cavity fluid, and blood. Organ pathology was assessed in lungs, liver, and kidneys. Lung myeloperoxidase activity, and plasma concentrations of alanine aminotransferase (ALT), creatinine, cell-free DNA (cfDNA), protein C, thrombin-antithrombin (TAT) complexes, interleukin (IL)-6, and IL-10 were also measured 6 h postoperatively. Morbidity was assessed for 16 h following CLP.

RESULTS

Overexpression of PCSK9 in mice increased liver and kidney pathology, plasma IL-6, ALT, and TAT concentrations during sepsis, whereas PCSK9 KO mice exhibited reduced bacterial loads, lung and liver pathology, myeloperoxidase activity, plasma IL-10, and cfDNA during CLP-induced sepsis. All septic mice had reduced plasma levels of protein C, but the protein C ratio relative to normal was significantly decreased in PCSK9 Tg mice. Dyspnea, cyanosis, and overall grimace scores were greatest in septic mice overexpressing PCSK9, whereas PCSK9 KO mice retained core body temperature during sepsis.

CONCLUSION

These findings demonstrate that PCSK9 deficiency confers protection against systemic bacterial dissemination, organ pathology, and tissue inflammation, particularly in the lungs and liver, while PCSK9 overexpression exacerbates multi-organ pathology as well as the hypercoagulable and pro-inflammatory states in early sepsis.

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.

Current insights into the German lipoprotein apheresis standard: PCSK9-inhibitors, lipoprotein apheresis or both?

According to current European guidelines, lipid lowering therapy for progressive cardiovascular disease including cardiovascular events has to be focused on a target level for LDL-C. In contrast for Lp(a) a threshold has to be defined with respect to the method of measurement. However, due to new lipid lowering drug developments like PCSK9-inhibitors (PCSK-9-I) a therapeutic algorithm for patients with severe hypercholesterolemia or isolated Lipoprotein(a)-hyperlipoproteinemia with progressive cardiovascular disease may be necessary to manage the use of PCSK9-I, lipoprotein apheresis (LA) or both. The therapeutic approach for patients with homozygous familial hypercholesterolemia is unambiguous: In addition to LA, in order to improve LDL-C reduction, PCSK9-I could be applied. In patients with heterozygous familial hypercholesterolemia, PCSK9-I is to be applied first. If in addition to a pronounced LDL-C elevation, cardiovascular complications exist or if imaging techniques documented atherosclerotic changes pre-disposing for a cardiovascular event while LDL-C reduction is insufficiently reduced (LDL-C > 100 mg/dl (2.6 mmol/l)), LA treatment should then be applied as last resort. In patients with elevated Lp(a) concentrations (Lp(a) > 60 mg/dl (>120 nmol/l)) and established cardiovascular disease, therapy should rely primarily on LA methods. If in addition to high Lp(a) levels insufficiently treated LDL-C concentrations (LDL-C > 100 mg/dl (2.6 mmol/l)) exist, in rare cases PCSK9-I can supplement the lipid lowering concept.

Austrian Lipid Consensus on the management of metabolic lipid disorders to prevent vascular complications: A joint position statement issued by eight medical societies. 2016 update

In 2010, eight Austrian medical societies proposed a joint position statement on the management of metabolic lipid disorders for the prevention of vascular complications. An updated and extended version of these recommendations according to the current literature is presented, referring to the primary and secondary prevention of vascular complications in adults, taking into consideration the guidelines of other societies. The "Austrian Lipid Consensus - 2016 update" provides guidance for individualized risk stratification and respective therapeutic targets, and discusses the evidence for reducing vascular endpoints with available lipid-lowering therapies. Furthermore, specific management in key patient groups is outlined, including subjects presenting with coronary, cerebrovascular, and/or peripheral atherosclerosis; diabetes mellitus and/or metabolic syndrome; nephropathy; and familial hypercholesterolemia.

PCSK9 inhibitors in the current management of atherosclerosis

The history of proprotein convertase subtilisin/kexin type 9 (PCSK9) in medical science is fascinating and the evolution of knowledge of its function has resulted in new medications of major importance for the cardiovascular (CV) patient. PCSK9 functions as a negative control or feedback for the cell surface receptors for low-density lipoprotein including its component of cholesterol (LDL-C). The initial and key findings were that different abnormalities of PCSK9 can result in an increase or a decrease of LDL-C because of more or less suppression of cell surface receptors. These observations gave hints and awoke interest that it might be possible to prepare monoclonal antibodies to PCSK9 and decrease its activity, after which there should be more active LDL-C cell receptors. The rest is a fascinating story that currently has resulted in two PCSK9 inhibitors, alirocumab and evolocumab, which, on average, decrease LDL-C approximately 50%. Nevertheless, if there are no contraindications, statins remain the standard of prevention for the high-risk CV patient and this includes both secondary and primary prevention. The new inhibitors are for the patient that does not attain the desired target for LDL-C reduction while taking a maximum statin dose or who does not tolerate any statin dose whatsoever. Atherosclerosis can be considered a metabolic disease and the clinician needs to realize this and think more and more of CV prevention. These inhibitors can contribute to both the stabilization and regression of atherosclerotic plaques and thereby avoid or delay major adverse cardiac events. (United States).

Systematic review of published Phase 3 data on anti-PCSK9 monoclonal antibodies in patients with hypercholesterolaemia

AIMS

Two anti-proprotein convertase subtilisin/kexin type 9 (PCSK9) monoclonal antibodies, alirocumab and evolocumab, have been approved for the treatment of hypercholesterolaemia in certain patients. We reviewed data from Phase 3 studies to evaluate the efficacy and safety of these antibodies.

METHODS

We systematically reviewed Phase 3 English-language studies in patients with hypercholesterolaemia, published between 1 January 2005 and 20 October 2015. Congress proceedings from 16 November 2012 to 16 November 2015 were also reviewed.

RESULTS

We identified 12 studies of alirocumab and nine of evolocumab, including over 10 000 patients overall. Most studies enrolled patients with hypercholesterolaemia and used anti-PCSK9 antibodies with statins. The ODYSSEY FH I, FH II and HIGH FH alirocumab studies and the RUTHERFORD-2 evolocumab study exclusively recruited patients with heterozygous familial hypercholesterolaemia. Two evolocumab studies focused mainly on homozygous familial hypercholesterolaemia (HoFH): TESLA Part B and TAUSSIG (a TESLA sub-study); only those data for HoFH are reported here. All comparator studies demonstrated a reduction in LDL cholesterol (LDL-C) with the anti-PCSK9 antibodies. No head-to-head studies were conducted between alirocumab and evolocumab. Up to 87% of patients receiving alirocumab and up to 98% receiving evolocumab reached LDL-C goals. Both antibodies were effective and well tolerated across a broad population of patients and in specific subgroups, such as those with type 2 diabetes.

CONCLUSIONS

Using anti-PCSK9 antibodies as add-on therapy to other lipid-lowering treatments or as monotherapy for patients unable to tolerate statins may help patients with high cardiovascular risk to achieve their LDL-C goals.

Effects of MAT9001 containing eicosapentaenoic acid and docosapentaenoic acid, compared to eicosapentaenoic acid ethyl esters, on triglycerides, lipoprotein cholesterol, and related variables

BACKGROUND

Long-chain omega-3 fatty acid concentrate pharmaceuticals are used in the United States for treatment of severe hypertriglyceridemia (≥500 mg/dL) and are under investigation as adjuncts to statins for lowering cardiovascular risk in patients with high triglycerides (TGs; 200-499 mg/dL).

OBJECTIVE

To evaluate MAT9001, an investigational prescription-only omega-3 fatty acid agent containing predominantly eicosapentaenoic acid (EPA) and docosapentaenoic acid, in 42 men and women with fasting TG 200 to 400 mg/dL.

METHODS

In this open-label, crossover trial, subjects received MAT9001 and EPA ethyl esters (EPA-EE) in random order. They were housed in a clinical research unit for 2 14-day treatment periods, separated by a ≥35-day washout. Lipoprotein lipids, apolipoproteins (Apos) and proprotein convertase subtilisin kexin type 9 levels were measured before and at the end of each treatment period.

RESULTS

MAT9001, compared with EPA-EE, resulted in significantly (P < .05) larger reductions from pretreatment levels for TG (-33.2% vs -10.5%), total cholesterol (-9.0% vs -6.2%), non-high-density lipoprotein cholesterol (-8.8% vs -4.6%), very low-density lipoprotein cholesterol (-32.5% vs -8.1%), Apo C3 (-25.5% vs -5.0%), and proprotein convertase subtilisin kexin type 9 (-12.3% vs +8.8%). MAT9001 also produced a significantly (P = .003) larger reduction in Apo A1 (-15.3% vs -10.2%), but responses for high-density lipoprotein cholesterol (-11.3% vs -11.1%), low-density lipoprotein cholesterol (-2.4% vs -4.3%), and Apo B (-3.8% vs -0.7%), respectively, were not significantly different relative to EPA-EE.

CONCLUSIONS

MAT9001 produced significantly larger reductions than EPA-EE in several lipoprotein-related variables that would be expected to favorably alter cardiovascular disease risk in men and women with hypertriglyceridemia.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors: Present perspectives and future horizons

AIMS

Our comprehensive review highlights the drug development and pharmacogenomics leading to the recent approval of PCSK9 inhibitors. We also review the anticipated future advances into the uses of PCSK9 inhibition.

BACKGROUND

Despite the present advances in pharmacotherapy, atherosclerotic cardiovascular disease (ASCVD) remains the leading cause of mortality worldwide. Low density lipoprotein-cholesterol (LDL-C) lowering is the primary target for ASCVD risk reduction, showing demonstrable benefits in mortality. However, 70% of events occur even in the presence of statins. This residual risk may be approached with additional LDL-C reduction. Statin intolerance is a common clinical concern affecting adherence and the benefit with statins. There is also significant variation of individual lipid-lowering. Following rapid development, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors have progressed from genetic observations, to mechanistic studies, to closer realization of the goal of CVD risk reduction. This review discusses the science behind PCSK9 inhibition, evidence of trials involving efficacy and safety, and reflections of its present and future role in clinical care, especially in high-risk patients with ASCVD, persons with suboptimal responses to statins and familial hyperlipidemia. Monoclonal antibodies have demonstrated LDL-C lowering of up to 57% as monotherapy and up to 73% when added to statins. Statins have limited efficacy in reduction of LDL-C due to an increased number of LDL-receptors. Elevated lipoprotein (a) levels may also be significantly lowered by PCSK9i. The journey from discovery to PSCK9 target validation took less than five years, and development and approval of therapeutic modalities for PCSK9 inhibitors happened over the next seven. This review highlights the drug development and pharmacogenomics leading to the recent approval of two agents, alirocumab and evolocumab, with a third bococizumab, and other novel approaches to the pathway pending.

DATA SYNTHESIS

We searched MEDLINE database via Pubmed for reviews, research publications and relevant trials available on PCSK9 inhibition.

CONCLUSION

Despite decades of medical advances, ASCVD remains one of the major causes of morbidity and mortality worldwide. Statin use has multiplied since the validation of LDL hypothesis, however, it is undeniable a more effective and well-tolerated agent is needed in significant number or patients. With the arrival of the era of unprecedented CV protection with PCSK9 inhibition, this exciting new therapy holds a pivotal promise as the future of lipid management. The data available already indicate safety, tolerability and superb efficacy of these agents, which are already changing contemporary cholesterol management. The rapid translation of innovative basic science research into drug development may lead to CV outcomes reduction and confirm that this pathway will become prominently utilized.

Managing the lipid profile of coronary heart disease patients

INTRODUCTION

Lipid profile management is even more critical in patients treated for secondary prevention, since patients with established coronary heart disease are at higher risk of developing events. Current guidelines encourage lifestyle modification and patient engagement in disease prevention. However, the American College of Cardiology/American Heart Association guidelines seem to differ considerably from their predecessors, having an impact on clinical practice of lipid management. Area covered: This review article discusses and provides a summary of the current recommendations for lipid profile management in patients with coronary heart disease, with a view to present lifestyle modification and novel treatment strategies, and to indicate areas of dispute among recent guidelines. Expert commentary: Existing controversies between current guidelines concerning treatment goals and therapeutic decisions may have potential implications on the clinical management of patients. In the meantime, we eagerly wait for the results of randomized controlled trials evaluating promising, potent, safe and prolonged drugs that are in progress.

Efficacy and Safety of Alirocumab in Japanese Patients With Heterozygous Familial Hypercholesterolemia or at High Cardiovascular Risk With Hypercholesterolemia Not Adequately Controlled With Statins - ODYSSEY JAPAN Randomized Controlled Trial

BACKGROUND

The ODYSSEY Japan study was designed to demonstrate the reduction in low-density lipoprotein cholesterol (LDL-C) by alirocumab as add-on to existing lipid-lowering therapy in Japanese patients with heterozygous familial hypercholesterolemia (heFH) or non-FH at high cardiovascular risk who require additional pharmacological management to achieve their LDL-C treatment goal (<2.6 or <3.1 mmol/L, depending on risk category).

METHODS AND RESULTS

This randomized, double-blind, parallel-group, 52-week study was conducted in Japan. Patients (n=216) with heFH, non-FH at high cardiovascular risk with coronary disease, or classified as category III were enrolled. The prespecified safety analysis was done after the last patient completed 52 weeks. Patients were randomized (2:1, alirocumab:placebo) with stratification for heFH to s.c. alirocumab (75 mg every 2 weeks [Q2 W] with increase to 150 mg if week 8 LDL-C ≥2.6/3.1 mmol/L) or placebo for 52 weeks plus stable statin therapy. At week 24, mean±SE change in LDL-C from baseline was -62.5±1.3% in the alirocumab group and 1.6±1.8% in the placebo group (difference, -64.1±2.2%; P<0.0001); the reduction was sustained to week 52 (alirocumab, -62.5±1.4%; placebo, -3.6±1.9%). No patterns were evident between treatment groups for adverse events at 52 weeks.

CONCLUSIONS

In high-risk Japanese patients with hypercholesterolemia on stable statin therapy, alirocumab markedly reduced LDL-C vs. placebo and was well tolerated over 52 weeks. (Circ J 2016; 80: 1980-1987).

New developments in proprotein convertase subtilisin-kexin 9's biology and clinical implications

PURPOSE OF REVIEW

High levels of LDL-cholesterol (LDL-C) are directly associated with devastating cardiovascular complications. Statins downregulate cholesterol synthesis and upregulate hepatic mRNA levels of LDL receptor (LDLR) and proprotein convertase subtilisin-kexin 9 (PCSK9), a validated enhancer of LDLR protein degradation. Herein, we summarize recent discoveries of the biological properties of PCSK9 in both health and disease states.

RECENT FINDINGS

PCSK9 downregulation of the LDLR protein likely explains the observed protective effect of the loss of PCSK9 in reducing lipoprotein(a) and incidence of septic shock. Injectable inhibitory PCSK9 monoclonal antibodies are now prescribed to hypercholesterolemic patients that do not reach target levels of LDL-C with available drugs. PCSK9 also reduces the levels of other receptors, for example, VLDL receptor (VLDLR), ApoER2, CD36, and CD81. The efficacy of the upregulation of LDLR and VLDLR cell surface levels in the absence of PCSK9 is both tissue and sex dependent. As LDLR, CD81, and VLDLR are hepatitis C receptors, PCSK9 may protect against certain viral infections.

SUMMARY

New functions of PCSK9 and other receptor targets are beginning to emerge to explain the observed changes in LDL-C and triglycerides. The effect of PCSK9 loss-of-function on glucose metabolism, factors that regulate the expression of PCSK9, and the roles of PCSK9 in other tissues, for example, intestine, kidney, and brain require further investigations.

[Introduction of PCSK9 inhibitors : New perspectives in treatment and practical implementation]

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is of critical importance in the regulation of the low-density lipoprotein (LDL) receptor-mediated metabolism of cholesterol. The discovery of mutations in the gene encoding PCSK9 in families with an autosomal dominant form of familial hypercholesterolemia (FH), which were later shown to be "gain-of-function" mutations, led to the development of antibodies against PCSK9. The efficacy in markedly reducing levels of LDL-cholesterol and preliminary evidence for benefits in the prevention of cardiovascular diseases indicated that special groups of patients can be more effectively treated. This includes forms of hypercholesterolemia refractory to conventional treatment as well as patients with FH and/or statin intolerance. Further information on long-term efficacy, tolerability and cost-effectiveness of PCSK9 inhibition and possibilities of implementation in the healthcare system are awaited from ongoing clinical outcome trials, such as FOURIER, ODYSSEY OUTCOMES, SPIRE 1 and 2 involving more than 70,000 high-risk patients.