Role of PCSK9 inhibition during the inflammatory stage of SARS-COV-2: an updated review

The potential role of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition in the management of COVID-19 and other medical conditions has emerged as an intriguing area of research. PCSK9 is primarily known for its impact on cholesterol metabolism, but recent studies have unveiled its involvement in various physiological processes, including inflammation, immune regulation, and thrombosis. In this abstract, the authors review the rationale and potential implications of PCSK9 inhibition during the inflammatory stage of SARS-CoV-2 infection. Severe cases of COVID-19 are characterized by an uncontrolled inflammatory response, often referred to as the cytokine storm, which can lead to widespread tissue damage and organ failure. Preclinical studies suggest that PCSK9 inhibition could dampen this inflammatory cascade by reducing the production of pro-inflammatory cytokines. Additionally, PCSK9 inhibition may protect against acute respiratory distress syndrome (ARDS) through its effects on lung injury and inflammation. COVID-19 has been linked to an increased risk of cardiovascular complications, especially in patients with pre-existing cardiovascular conditions or dyslipidemia. PCSK9 inhibitors are known for their ability to lower low-density lipoprotein (LDL) cholesterol levels by enhancing the recycling of LDL receptors in the liver. By reducing LDL cholesterol, PCSK9 inhibition might protect blood vessels from further damage and lower the risk of atherosclerotic plaque formation. Moreover, PCSK9 inhibitors have shown potential antithrombotic effects in preclinical studies, making them a potential avenue to mitigate the increased risk of coagulation disorders and thrombotic events observed in COVID-19. While the potential implications of PCSK9 inhibition are promising, safety considerations and possible risks need careful evaluation. Hypocholesterolemia, drug interactions, and long-term safety are some of the key concerns that should be addressed. Clinical trials are needed to establish the efficacy and safety of PCSK9 inhibitors in COVID-19 patients and to determine the optimal timing and dosing for treatment. Future research opportunities encompass investigating the immune response, evaluating long-term safety, exploring combination therapy possibilities, and advancing personalized medicine approaches. Collaborative efforts from researchers, clinicians, and policymakers are essential to fully harness the therapeutic potential of PCSK9 inhibition and translate these findings into meaningful clinical outcomes.

PCSK9 genetic variants and risk of vascular and non-vascular diseases in Chinese and UK populations

AIM

Lowering low-density lipoprotein cholesterol (LDL-C) through PCSK9 inhibition represents a new therapeutic approach to preventing and treating cardiovascular disease (CVD). Phenome-wide analyses of PCSK9 genetic variants in large biobanks can help to identify unexpected effects of PCSK9 inhibition.

METHODS

In the prospective China Kadoorie Biobank, we constructed a genetic score using three variants at the PCSK9 locus associated with directly-measured LDL-C (PCSK9-GS). Logistic regression gave estimated odds ratios (ORs) for PCSK9-GS associations with CVD and non-CVD outcomes, scaled to 1SD lower LDL-C.

RESULTS

PCSK9-GS was associated with lower risks of carotid plaque (n=8340 cases; OR=0.61 [95%CI: 0.45-0.83]; P=0.0015), major occlusive vascular events (n=15,752; 0.80 [0.67-0.95]; P=0.011), and ischaemic stroke (n=11,467; 0.80 [0.66-0.98]; P=0.029). However, PCSK9-GS was also associated with higher risk of hospitalisation with chronic obstructive pulmonary disease (COPD: n=6836; 1.38 [1.08-1.76]; P=0.0089), and with even higher risk of fatal exacerbations among individuals with pre-existing COPD (n=730; 3.61 [1.71-7.60]; P=7.3x10-4). We also replicated associations for a PCSK9 variant, reported in UK Biobank, with increased risks of acute upper respiratory tract infection (URTI) (pooled OR after meta-analysis of 1.87 ([1.38-2.54]; P=5.4x10-5) and self-reported asthma (pooled OR 1.17 ([1.04-1.30]; P=0.0071). There was no association of a polygenic LDL-C score with COPD hospitalisation, COPD exacerbation, or URTI.

CONCLUSIONS

LDL-C-lowering PCSK9 genetic variants are associated with lower risk of subclinical and clinical atherosclerotic vascular disease, but higher risks of respiratory diseases. Pharmacovigilance studies may be required to monitor patients treated with therapeutic PCSK9 inhibitors for exacerbations of respiratory diseases or respiratory tract infections.

Platelet activation and endothelial dysfunction biomarkers in acute coronary syndrome: the impact of PCSK9 inhibition

AIMS

Platelet activation and endothelial dysfunction contribute to adverse outcomes in patients with acute coronary syndromes (ACS). The goals of this study were to assess the impact of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition on markers of platelet activation and endothelial dysfunction in ACS patients and the interaction among PCSK9, platelets, and endothelial cells (ECs) on left internal mammary artery (LIMA) vascular endothelium using specimens obtained during coronary artery bypass surgery (CABG).

METHODS AND RESULTS

Acute coronary syndromes patients enrolled in the Evolocumab in ACS trials were randomized to placebo or a single dose of 420 mg evolocumab within 24 h of hospitalization. Serum samples for analysis of platelet factor 4 (PF4) and P-selectin, markers of platelet activation, and von Willebrand factor (vWF), a marker of endothelial dysfunction, were obtained at baseline and 30 days. Additionally, LIMA segments obtained during CABG from patients who were and were not receiving evolocumab were immunostained with PCSK9; CD61, a platelet-specific marker; and CD31, an endothelial cell-specific marker. Forty-six participants were randomized to placebo or to evolocumab. Controlling for baseline levels, PF4 and vWF were significantly lower in the evolocumab, than in the placebo, group at 30 days. Immunostaining of LIMA specimens from twelve participants undergoing CABG revealed colocalization of PCSK9, CD61, and CD31 at the vascular endothelium. Administration of evolocumab was associated with decreased overlap of PCSK9, CD61, and CD31.

CONCLUSIONS

Proprotein Convertase Subtilisin/Kexin 9 inhibition decreases markers of platelet activation and endothelial dysfunction in ACS patients. PCSK9 is associated with platelets and vascular ECs in LIMA segments and PCSK9 inhibition decreases that interaction.

First clinical experiences with inclisiran in a real-world setting

BACKGROUND AND OBJECTIVE

Inclisiran is the first-in-class small interfering RNA (siRNA) proprotein convertase subtilisin kexin type 9 (PCSK9) inhibitor. In clinical trials inclisiran showed effective and sustained low-density lipoprotein cholesterol (LDL-C) reduction of ± 50 %. As data in clinical setting are scarce, we aim to investigate the efficacy and safety in clinical practice.

METHODS

We describe a registry of consecutive patients who started with inclisiran at a lipid clinic of a university hospital. Patients were eligible if they fulfilled the reimbursement criteria in the Netherlands. Patients were included if they started with inclisiran as first line (group 1) or switched from PCSK9 monoclonal antibody (mAbs) to inclisiran (group 2). LDL-C levels were measured at 3 and 9 months after initiation of inclisiran. Median change of LDL-C levels was calculated on an individual and group level.

RESULTS

We analysed 65 patients (36 women), median [25th percentile; 75th percentile] age of 63 [54; 68] years. Of these, 44 patients had both a 3 month and 9 month visit. At 3 months, patients who newly started inclisiran (group 1, n = 45) showed a LDL-C decrease of 38 [-49;-33] %. Patients who used statins as co-medication (n = 15) had a higher median LDL-C decrease compared to those without statin use (n=30; 45 % vs 38 %). However, patients who switched from mAbs to inclisiran (group 2, n = 20) had an increase in LDL-C of 38 [+4; +97] %. Adverse effects associated with inclisiran were mild and consisted of mild injection site reactions. Efficacy was slightly less whereas safety results were similar at 9 months.

CONCLUSION

Our initial experience of inclisiran in a clinical setting showed less reduction in LDL-C levels compared to clinical trials but a similar safety profile. Moreover, patients who switched from PCSK9 mAbs to inclisiran generally showed an increase in LDL-C levels implying that inclisiran is less potent in LDL-C reduction compared to PCSK9 mAbs.

Alirocumab and plaque volume, calf muscle blood flow, and walking performance in peripheral artery disease: A randomized clinical trial

BACKGROUND

The distal superficial femoral artery (SFA) is most commonly affected in peripheral artery disease (PAD). The effects of the proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor alirocumab added to statin therapy on SFA atherosclerosis, downstream flow, and walking performance are unknown.

METHODS

Thirty-five patients with PAD on maximally tolerated statin therapy were recruited. Patients were randomized to alirocumab 150 mg subcutaneously (n = 18) or matching placebo (n = 17) therapy every 2 weeks for 1 year. The primary outcome was change in SFA plaque volume by black blood magnetic resonance imaging (MRI). Secondary outcomes were changes in calf muscle perfusion by cuff/occlusion hyperemia arterial spin labeling MRI, 6-minute walk distance (6MWD), low-density lipoprotein (LDL) cholesterol, and other biomarkers.

RESULTS

Age (mean ± SD) was 64 ± 8 years, 20 (57%) patients were women, 17 (49%) were Black individuals, LDL was 107 ± 36 mg/dL, and the ankle-brachial index 0.71 ± 0.20. The LDL fell more with alirocumab than placebo (mean [95% CI]) (-49.8 [-66.1 to -33.6] vs -7.7 [-19.7 to 4.3] mg/dL; p < 0.0001). Changes in SFA plaque volume and calf perfusion showed no difference between groups when adjusted for baseline (+0.25 [-0.29 to 0.79] vs -0.04 [-0.47 to 0.38] cm3; p = 0.37 and 0.22 [-8.67 to 9.11] vs 3.81 [-1.45 to 9.08] mL/min/100 g; p = 0.46, respectively), nor did 6MWD.

CONCLUSION

In this exploratory study, the addition of alirocumab therapy to statins did not alter SFA plaque volume, calf perfusion or 6MWD despite significant LDL lowering. Larger studies with longer follow up that include plaque characterization may improve understanding of the effects of intensive LDL-lowering therapy in PAD (ClinicalTrials.gov Identifier: NCT02959047).

The Inhibition of Evolocumab on Non-Infarct-Related Artery Disease in Patients with ST-Elevation Myocardial Infarction

Purpose

The effects of combing evolocumab and statin on the clinical outcome and physiological function of coronary arteries in STEMI patients with non-infarct-related artery (NIRA) disease are still unclear.

Methods

A total of 355 STEMI patients with NIRA were enrolled in this study, who underwent combined quantitative flow ratio (QFR) at baseline and after 12 months of treatment with statin monotherapy or statin plus evolocumab.

Results

Diameter stenosis and lesion length were significantly lower in the group undergoing statin plus evolocumab. While the group exhibited significantly higher minimum lumen diameter (MLD), and QFR values. Statin plus evolocumab (OR = 0.350; 95% CI: 0.149-0.824; P = 0.016) and plaque lesion length (OR = 1.223; 95% CI: 1.102-1.457; P = 0.033) were independently associated with rehospitalization for unstable angina (UA) within 12 months.

Conclusion

Evolocumab combined with statin therapy can significantly improve the anatomical and physiological function of the coronary arteries and downregulate the re-hospitalization rate due to UA in STEMI patients with NIRA.

PCSK9 Inhibition During the Inflammatory Stage of SARS-CoV-2 Infection

BACKGROUND

The intensity of inflammation during COVID-19 is related to adverse outcomes. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is involved in low-density lipoprotein receptor homeostasis, with potential influence on vascular inflammation and on COVID-19 inflammatory response.

OBJECTIVES

The goal of this study was to investigate the impact of PCSK9 inhibition vs placebo on clinical and laboratory outcomes in patients with severe COVID-19.

METHODS

In this double-blind, placebo-controlled, multicenter pilot trial, 60 patients hospitalized for severe COVID-19, with ground-glass opacity pneumonia and arterial partial oxygen pressure to fraction of inspired oxygen ratio ≤300 mm Hg, were randomized 1:1 to receive a single 140-mg subcutaneous injection of evolocumab or placebo. The primary endpoint was death or need for intubation at 30 days. The main secondary endpoint was change in circulating interleukin (IL)-6 at 7 and 30 days from baseline.

RESULTS

Patients randomized to receive the PCSK9 inhibitor had lower rates of death or need for intubation within 30 days vs placebo (23.3% vs 53.3%, risk difference: -30%; 95% CI: -53.40% to -6.59%). Serum IL-6 across time was lower with the PCSK9 inhibitor than with placebo (30-day decline: -56% vs -21%). Patients with baseline IL-6 above the median had lower mortality with PCSK9 inhibition vs placebo (risk difference: -37.50%; 95% CI: -68.20% to -6.70%).

CONCLUSIONS

PCSK9 inhibition compared with placebo reduced the primary endpoint of death or need for intubation and IL-6 levels in severe COVID-19. Patients with more intense inflammation at randomization had better survival with PCSK9 inhibition vs placebo, indicating that inflammatory intensity may drive therapeutic benefits. (Impact of PCSK9 Inhibition on Clinical Outcome in Patients During the Inflammatory Stage of the COVID-19 [IMPACT-SIRIO 5]; NCT04941105).

PCSK9 is minimally associated with HDL but impairs the anti-atherosclerotic HDL effects on endothelial cell activation

Proprotein Convertase Subtilisin/Kexin type 9 (PCSK9) regulates the cell-surface localization of LDL receptors in hepatocytes and is associated with LDL and lipoprotein(a) [Lp(a)] uptake, reducing blood concentrations. However, the connection between PCSK9 and HDL is unclear. Here, we investigated the association of plasma PCSK9 with HDL subpopulations and examined the effects of PCSK9 on the atheroprotective function of HDL. We examined the association of PCSK9 with HDL in apoB-depleted plasma by ELISA, native PAGE, and immunoblotting. Our analyses showed that upon apoB-depletion, total circulating PCSK9 levels were 32% of those observed in normolipidemic plasma, and only 6% of PCSK9 in the apoB-depleted plasma, including both the mature and furin-cleaved forms, was associated with HDL. We also show human recombinant PCSK9 abolished the capacity of reconstituted HDL to reduce the formation of ROS in endothelial cells, while a PCSK9-blocking antibody enhanced the capacity of human HDL (in apoB-depleted plasma) to reduce ROS formation in endothelial cells and promote endothelial cell migration. Overall, our findings suggest that PCSK9 is only minimally associated with HDL particles, but PCSK9 in apoB-depleted plasma can affect the atheroprotective properties of HDL related to preservation of endothelial function. This study contributes to the elucidation of the pathophysiological role of plasma PCSK9 and highlights further the anti-atherosclerotic effect of PCSK9 inhibition.

Lipid lowering with bempedoic acid added to a proprotein convertase subtilisin/kexin type 9 inhibitor therapy: A randomized, controlled trial

BACKGROUND

Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9is) lower low-density lipoprotein cholesterol (LDL-C) in patients with hypercholesterolemia. However, some patients receiving PCSK9i therapy might require additional lipid-lowering therapy (LLT) to reach LDL-C goals. Bempedoic acid is an oral, once-daily, ATP-citrate lyase inhibitor that significantly lowers LDL-C in patients with hypercholesterolemia when given alone or as add-on therapy to statins and/or ezetimibe.

OBJECTIVE

Assess safety and efficacy of bempedoic acid added to PCSK9i (evolocumab) background therapy in patients with hypercholesterolemia.

METHODS

This phase 2, randomized, double-blind, placebo-controlled study was conducted in three phases: 1.5-month screening/washout period including discontinuation of all LLTs, a 3-month period wherein patients initiated background PCSK9i therapy, and a 2-month treatment period in which patients were randomized 1:1 to receive bempedoic acid 180 mg or placebo once daily while continuing PCSK9i therapy.

RESULTS

Of 59 patients randomized, 57 completed the study. Mean baseline LDL-C after 3 months of PCSK9i background therapy was 103.1 ± ± 30.4 mg/dL. Bempedoic acid added to background PCSK9i therapy significantly lowered LDL-C by 30.3% (P < .001) vs placebo. Compared with placebo, bempedoic acid significantly lowered apolipoprotein B, non-high-density lipoprotein cholesterol, and total cholesterol (nominal P < .001 for all), and high-sensitivity C-reactive protein (P = .029). When added to background PCSK9i therapy, the safety profile of bempedoic acid was comparable to that observed for placebo.

CONCLUSIONS

When added to a background of PCSK9i therapy, bempedoic acid significantly lowered LDL-C levels with a safety profile comparable to placebo in patients with hypercholesterolemia.

Effect of alirocumab on major adverse cardiovascular events according to renal function in patients with a recent acute coronary syndrome: prespecified analysis from the ODYSSEY OUTCOMES randomized clinical trial

Aims

Statins reduce cardiovascular risk in patients with acute coronary syndrome (ACS) and normal-to-moderately impaired renal function. It is not known whether proprotein convertase subtilisin-kexin type 9 (PCSK9) inhibitors provide similar benefit across a range of renal function. We determined whether effects of the PCSK9 inhibitor alirocumab to reduce cardiovascular events and death after ACS are influenced by renal function.

Methods and results

ODYSSEY OUTCOMES compared alirocumab with placebo in patients with recent ACS and dyslipidaemia despite intensive statin treatment. Estimated glomerular filtration rate (eGFR) <30 mL/min/1.73 m² was exclusionary. In 18 918 patients, baseline eGFR was 82.8 ± 17.6 mL/min/1.73 m², and low-density lipoprotein cholesterol (LDL-C) was 92 ± 31 mg/dL. At 36 months, alirocumab decreased LDL-C by 48.5% vs. placebo but did not affect eGFR (P = 0.65). Overall, alirocumab reduced risk of the primary outcome (coronary heart disease death, non-fatal myocardial infarction, ischaemic stroke, or unstable angina requiring hospitalization) with fewer deaths. There was no interaction between continuous eGFR and treatment on the primary outcome or death (P = 0.14 and 0.59, respectively). Alirocumab reduced primary outcomes in patients with eGFR ≥90 mL/min/1.73 m² (n = 7470; hazard ratio 0.784, 95% confidence interval 0.670–0.919; P = 0.003) and 60 to <90 (n = 9326; 0.833, 0.731–0.949; P = 0.006), but not in those with eGFR < 60 (n = 2122; 0.974, 0.805–1.178; P = 0.784). Adverse events other than local injection-site reactions were similar in both groups across all categories of eGFR.

Conclusions

In patients with recent ACS, alirocumab was associated with fewer cardiovascular events and deaths across the range of renal function studied, with larger relative risk reductions in those with eGFR > 60 mL/min/1.73 m².

Effects of evolocumab in individuals with type 2 diabetes with and without atherogenic dyslipidemia: An analysis from BANTING and BERSON

Background

Atherogenic dyslipidemia (AD), characterized by increased concentrations of apolipoprotein B (ApoB)-containing particles, is often present in individuals with type 2 diabetes mellitus (T2DM). Non-high-density lipoprotein cholesterol (non-HDL-C), cholesterol transported by apolipoprotein B (ApoB)-containing particles), and total apoB are considered secondary goals of lipid-lowering therapy to guide treatment of residual cardiovascular risk. The BANTING and BERSON studies demonstrated that evolocumab added to statin therapy reduced atherogenic lipid and lipoproteins concentrations in patients with T2DM.

Methods

This post-hoc analysis combined data from two randomized, placebo-controlled trials, BANTING and BERSON, to investigate the effect of evolocumab (140 mg every two weeks [Q2W] or 420 mg monthly [QM]) on atherogenic lipid (LDL-C, non-HDL-C, VLDL-C, remnant cholesterol) and lipoproteins (ApoB, lipoprotein(a) (Lp[a])), and achievement of 2019 European Society of Cardiology/European Atherosclerosis Society lipid treatment goals in individuals with and without AD.

Results

In individuals with high TGs with (n = 389) and without (n = 196) AD receiving background statin therapy, evolocumab, compared with placebo, substantially reduced the cholesterol levels from all ApoB atherogenic lipoproteins (least squares (LS) mean LDL-C by 66.7% to 74.3%, non-HDL-C by 53.4% to 65.8%, median remnant cholesterol by 28.9% to 34.2%, VLDL-C by 16.1% to 19.6%) and median TGs levels (by 17.5% to 19.6%) at the mean of weeks 10 and 12. LS mean ApoB was significantly reduced by 41.5% to 56.6% at week 12. Results were consistent in diabetic individuals with normal TGs (n = 519). Evolocumab was also associated with a significant reduction in median Lp(a) by 35.0% to 53.9% at the mean of weeks 10 and 12. A majority (74.7% to 79.8%) of evolocumab-treated individuals achieved the goal of both an LDL-C < 1.4 mmol/L and an LDL-C reduction of at least 50%, > 75% achieved non-HDL-C < 2.2 mmol/L at the mean of weeks 10 and 12, and > 67% achieved ApoB < 65 mg/dL at week 12.

Conclusions

Evolocumab effectively reduced LDL-C, non-HDL-C, ApoB, Lp(a), and remnant cholesterol in individuals with T2DM with and without AD. Evolocumab Q2W or QM enabled most individuals at high/very-high cardiovascular disease risk to achieve their LDL-C, non-HDL-C, and ApoB recommended goals.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-021-01287-6.

Protein convertase subtilisin/kexin type 9 biology in nephrotic syndrome: implications for use as therapy

Low-density lipoprotein cholesterol (LDL-C) levels almost constantly increased in patients with nephrotic syndrome (NS). Protein convertase subtilisin/kexin type 9 (PCSK9) [accelerates LDL-receptor (LDL-R) degradation] is overexpressed by liver cells in NS. Their levels, correlated inversely to LDL-R expression and directly to LDL-C, seem to play a central role in hypercholesterolaemia in NS. Hypersynthesis resulting from sterol regulatory element-binding protein dysfunction, hyperactivity induced by c-inhibitor of apoptosis protein expressed in response to stimulation by tumour necrosis factor-α produced by damaged podocytes and hypo-clearance are the main possible mechanisms. Increased LDL-C may damage all kidney cell populations (podocytes, mesangial and tubular cells) in a similar manner. Intracellular cholesterol accumulation produces oxidative stress, foam cell formation and apoptosis, all favoured by local inflammation. The cumulative effect of cellular lesions is worsened proteinuria and kidney function loss. Accordingly, NS patients should be considered high risk and treated by lowering LDL-C. However, there is still not enough evidence determining whether lipid-lowering agents are helpful in managing dyslipidaemia in NS. Based on good efficacy and safety proved in the general population, therapeutic modulation of PCSK9 via antibody therapy might be a reasonable solution. This article explores the established and forthcoming evidence implicating PCSK9 in LDL-C dysregulation in NS.

A Comparison of Ezetimibe and Evolocumab for Atherogenic Lipid Reduction in Four Patient Populations: A Pooled Efficacy and Safety Analysis of Three Phase 3 Studies

INTRODUCTION

Clinicians, payers, guideline committees, and policymakers support the use of high-intensity statins in patients at high risk for complications of cardiovascular disease (CVD). Guidelines and recommendations provide guidance on next steps for patients with inadequate low-density lipoprotein cholesterol (LDL-C) control on maximally tolerated statin or for those who are statin-intolerant. Ezetimibe and evolocumab improve CV outcomes when added to statins in high-CV-risk populations. The aim of the study was to compare evolocumab and ezetimibe for lipid-lowering efficacy and safety.

METHODS

We summarized data from 1427 patients from three phase 3 evolocumab studies comparing double-blinded evolocumab vs. ezetimibe. These studies evaluated four distinct populations: those free of CVD receiving each agent as monotherapy, patients with CVD receiving add-on therapy to low- or high-intensity statin, and statin-intolerant patients. Lipid efficacy and safety were reported at week 12.

RESULTS

Across the studies, evolocumab reduced LDL-C by a mean 55-61% from baseline to week 12; ezetimibe lowered LDL-C by 18-20% from baseline (mean difference = 38-43% favoring evolocumab; p < 0.0001). This corresponded to absolute reductions in LDL-C of 60-104 mg/dL with evolocumab vs. 17-35 mg/dL with ezetimibe. Evolocumab also significantly improved other lipids and led to a higher percentage of patients achieving LDL-C goals vs. ezetimibe. Adverse events and discontinuation rates (oral and parenteral therapy) were balanced across groups, suggesting good tolerance and acceptance of both treatments.

CONCLUSIONS

Evolocumab outperformed ezetimibe in efficacy and lipid goal attainment. Both products demonstrated good safety/tolerability. These data may help guide access decisions for high-risk patients with inadequate treatment response or intolerance to statin therapy.

New Pharmacological Approaches to Target PCSK9

PURPOSE OF REVIEW

Proprotein convertase subtilisin kexin 9 (PCSK9) plays a crucial role in regulating circulating levels of LDL-C as a consequence of its ability to inhibit LDL receptor recycling in the liver. Loss of function variants in the PCSK9 gene result in low LDL-C levels and associate with reduced cardiovascular risk, whereas gain of-function variants associate with hypercholesterolemia and increased risk of early cardiovascular events. Thus, PCSK9 inhibition has been established as an additional approach for the treatment of hypercholesterolemia. The aim of this review is to provide a brief overview of current strategies targeting PCSK9 and discuss clinical results of the emerging approaches.

RECENT FINDINGS

Two monoclonal antibodies targeting circulating PCSK9 (evolocumab and alirocumab) have been approved for the treatment of hypercholesterolemia and cardiovascular disease. Later, a gene silencing approach (inclisiran), which inhibits hepatic PCSK9 synthesis, was shown to be as effective as monoclonal antibodies but with a twice a year injection and is currently under evaluation for approval. Due to the elevated costs of such therapies, several other approaches have been explored, including peptide-based anti PCSK9 vaccination, and small oral PCSK9 inhibitors, which are still in preclinical phase. In the coming years, we will assist to a progressive introduction of novel anti-PCSK9 approaches in the clinical practice for the treatment of patients with hypercholesterolemia as well as patients at high cardiovascular risk.

Discordant responses of plasma low-density lipoprotein cholesterol and lipoprotein(a) to alirocumab: A pooled analysis from 10 ODYSSEY Phase 3 studies

AIMS

Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors consistently reduce low-density lipoprotein cholesterol (LDL-C) by 50-60% and lipoprotein(a) (Lp(a)) by 20-30%, but the mechanism of Lp(a) lowering remains unclear. If Lp(a) is cleared by the LDL receptor, similar to LDL-C, then one would expect PCSK9 inhibition to induce a concordant LDL-C/Lp(a) response in an approximately 2:1 ratio. We aim to determine the prevalence of discordant plasma LDL-C/Lp(a) response to the PCSK9 inhibitor alirocumab.

METHODS

This is a post hoc, pooled analysis of 10 randomized controlled trials from the ODYSSEY Phase 3 clinical trial program for alirocumab. Patients enrolled in the trials were high cardiovascular risk and/or with heterozygous familial hypercholesterolemia. The primary end point was prevalence of discordant LDL-C/Lp(a) response to alirocumab at 24 weeks. Discordant response was defined as LDL-C reduction >35% and Lp(a) reduction ≤10%, or LDL-C reduction ≤35% and Lp(a) reduction >10%.

RESULTS

Of the 1709 patients in the pooled study cohort, 62.4% were male, and the mean age was 59.2 (SD: 11.0) years. Baseline mean LDL-C was 126.5 (SD: 46.3) mg/dL and baseline median Lp(a) was 46.9 (interquartile range: 21.8-89.0) mg/dL. Total prevalence of discordant LDL-C/Lp(a) response was 21.5% (12.6% with LDL-C >35% reduction and Lp(a) ≤10% reduction; 8.9% with LDL-C ≤35% reduction and Lp(a) >10% reduction). Baseline Lp(a) and familial hypercholesterolemia status did not affect discordance.

CONCLUSION

A high prevalence of discordant LDL-C/Lp(a) response was observed with alirocumab, further suggesting that PCSK9 inhibitor therapy with alirocumab reduces plasma Lp(a) through alternative pathways to LDL receptor clearance.

PCSK9 Inhibition and Atherosclerosis: Current Therapeutic Option and Prospection

Low-density lipoprotein cholesterol (LDL-C) is a pivotal factor in atherosclerotic cardiovascular disease (ASCVD), the leading cause of worldwide mortality. The limitations of statin therapy require alternative treatment strategies to achieve target LDL-C level. Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays an important role in LDLR recycling, consequently regulating plasma cholesterol levels. Monoclonal antibodies targeting PCSK9 increased expression of LDLRs at the cell surface and therefore decreased circulating LDL-C. PCSK9 inhibitors have shown great efficacy in reducing plasma LDL-C levels, which needs to inject once or twice monthly. Though SPIRE sponsors concern the immunogenicity and terminate trials early, FOURIER and ODYSSER OUTCOME trials improved the efficacy of PCSK9 inhibitors in LDL-C reduction. Inclisiran actually is a small interfering RNA (siRNA) developed to inhibit PCSK9 messenger RNA, leading to reduced concentrations of the PCSK9 protein and thereby lower concentrations of LDL-C. Inclisiran is a latest alternative treatment to cholesterol-lowering therapeutics. Twice injections of inclisiran durably reduced LDL-C levels over 1 year. siRNA therapeutics provided a simple, novel, and less frequent approach to LDL-C reduction in phase I and II trials, which may be used either as in combination with statin therapeutics or a stand-alone therapy in the future.

PCSK9 inhibition and inflammation: A narrative review

Atherosclerotic cardiovascular disease (ASCVD) remains a leading cause of morbidity and mortality despite excellent pharmacological and revascularization approaches. Low-density lipoproteins (LDL) are undoubtedly the most significant biochemical variables associated with atheroma, however, compelling data identify inflammation as critical for the maintenance of the atherosclerotic process, underlying some of the most feared vascular complications. Although its causal role is questionable, high-sensitivity C-reactive protein (hs-CRP) represents a major biomarker of inflammation and associated risk in CVD. While statin-associated reduced risk may be related to the lowering of both LDL-C and hs-CRP, PCSK9 inhibitors leading to dramatic LDL-C reductions do no alter hs-CRP levels. On the other hand, hs-CRP levels identify groups of patients with a high risk of CV disease achieving better ASCVD prevention in response to PCSK9 inhibition. In the FOURIER study, even in patients with extremely low levels of LDL-C, there was a stepwise risk increment according to the values of hs-CRP: +9% (<1 mg/L), +10.8% (1-3 mg/L) and +13.1% (>3 mg/L). Likewise, in the SPIRE-1 and -2 studies, bococizumab patients with hs-CRP> 3 mg/L had a 60% greater risk of future CV events. Most of the patients enrolled in the PCSK9 trials were on maximally tolerated statin therapy at baseline, and an elevated hs-CRP may reflect residual inflammatory risk after standard LDL-C lowering therapy. Moreover, data on changes in inflammation markers in carriers of PCSK9 loss-of-function mutations are scanty and not conclusive, thus, evidence from the effects of anti-inflammatory molecules on PCSK9 levels might help unravel this hitherto complex tangle.

Efficacy and safety of evolocumab in individuals with type 2 diabetes mellitus: primary results of the randomised controlled BANTING study

AIMS/HYPOTHESIS

The study aimed to examine the efficacy of 12 weeks of monthly evolocumab or placebo in lowering LDL-cholesterol (LDL-C) in individuals with type 2 diabetes and hypercholesterolaemia or mixed dyslipidaemia and on a maximum-tolerated statin of at least moderate intensity.

METHODS

For this randomised, placebo-controlled outpatient study, eligible individuals were ≥18 years old with type 2 diabetes, HbA_1c <10% (86 mmol/mol), had been on stable pharmacological therapy for diabetes for ≥6 months and were taking a maximum-tolerated statin dose of at least moderate intensity. Lipid eligibility criteria varied by history of clinical cardiovascular disease. Participants were randomised 2:1 to evolocumab 420 mg s.c. or placebo. Randomisation was performed centrally via an interactive web-based or voice recognition system. Allocation was concealed using the centralised randomisation process. Treatment assignment was blinded to the sponsor study team, investigators, site staff and patients throughout the study. Co-primary endpoints were mean percentage change in LDL-C from baseline to week 12 and to the mean of weeks 10 and 12. Additional endpoints included LDL-C <1.81 mmol/l, LDL-C reduction ≥50% and other lipids. Exploratory analyses included percentage changes in fasting and post mixed-meal tolerance test (MMTT) lipoproteins and lipids, glucose metabolism variables and inflammatory biomarkers.

RESULTS

In total, 421 individuals were randomised and analysed, having received evolocumab (280 participants) or placebo (141 participants) (mean [SD] age 62 [8] years; 44% women; 77% white). Evolocumab decreased LDL-C by 54.3% (1.4%) at week 12 (vs 1.1% [1.9%] decrease with placebo; p < 0.0001) and by 65.0% (1.3%) at the mean of weeks 10 and 12 (vs 0.8% [1.8%] decrease with placebo; p < 0.0001); it also decreased non-HDL-cholesterol (HDL-C) by 46.9% (1.3%) at week 12 (vs 0.6% [1.8%] decrease with placebo) and by 56.6% (1.2%) at the mean of weeks 10 and 12 (vs 0.1% [1.6%] decrease with placebo). Evolocumab significantly improved levels of other lipids and allowed more participants to reach LDL-C <1.81 mmol/l or a reduction in LDL-C levels ≥50%. After an MMTT (120 min), there were favourable changes (p < 0.05; nominal, post hoc, no multiplicity adjustment) in chylomicron triacylglycerol (triglycerides), chylomicron cholesterol, VLDL-C and LDL-C. Evolocumab had no effect on glycaemic variables and was well tolerated.

CONCLUSIONS/INTERPRETATION

In statin-treated individuals with type 2 diabetes and hypercholesterolaemia or mixed dyslipidaemia, evolocumab significantly reduced LDL-C and non-HDL-C. Favourable changes (p < 0.05) were observed in postprandial levels of chylomicrons, VLDL-C and LDL-C.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02739984 FUNDING: This study was funded by Amgen Inc.

DATA AVAILABILITY

Qualified researchers may request data from Amgen clinical studies. Complete details are available at www.amgen.com/datasharing .

12-Week Effectiveness and Safety of Low-Density Lipoprotein Cholesterol-Lowering Therapy by Proprotein Convertase Subtilisin/Kexin Type 9 Inhibition in Patients With Familial Hypercholesterolemia and Hypercholesterolemia - Data From a Real-World Observational Study of Evolocumab in Japan

Background: Evolocumab is the first monoclonal antibody against proprotein convertase subtilisin/kexin type 9 (PCSK9) approved in Japan for the treatment of patients with familial hypercholesterolemia (FH) and hypercholesterolemia (HC). This study assessed the 12-week effectiveness and safety of low-density lipoprotein cholesterol (LDL-C)-lowering therapy by PCSK9 inhibition in patients with FH (homozygous [HoFH] or heterozygous [HeFH]) and HC by analyzing evolocumab data collected in the real-world setting in Japan.

Methods and Results: Overall, 427 patients (mean±SD age, 61.6±13.8 years; female, 38.4%; 28 HoFH, 320 HeFH, 79 HC), enrolled from 299 clinical sites, were included in the safety analysis set. The major cardiovascular risk factors were coronary artery disease (77.3%), diabetes mellitus/impaired glucose tolerance (38.6%), and hypertension (65.1%). Median follow-up duration was 85.0 days. After 12 weeks of evolocumab treatment, the mean±SD percent change from baseline in LDL-C was −45.5%±27.0% (n=23) in HoFH (P<0.001 vs. baseline; t-test), −54.2%±29.0% (n=280) in HeFH (P<0.001), and −64.6%±22.4% (n=72) in HC (P<0.001) patients. The incidence of adverse drug reactions was 5.4% (23/427).

Conclusions: Results suggest that patients receiving evolocumab treatment in the real-world setting were predominantly those with FH and HC in the secondary prevention group. LDL-C-lowering effectiveness with evolocumab was observed in FH (both HoFH and HeFH) and HC patients.

Lipid management in ACS: Should we go lower faster?

Low-density lipoprotein-cholesterol (LDL-C) is a well-accepted causal risk factor for athero-thrombotic cardiovascular disease, as demonstrated in large epidemiological studies, including Mendelian randomization data. Several randomized controlled trials and meta-analyzes have shown that lipid lowering therapies, such as statins and more recently the non-statin agents ezetimibe and Proprotein Convertase Subtilisin Kexin type 9 (PCSK9) monoclonal antibodies (mAb), reduce cardiovascular events across a broad range of baseline LDL-C levels. Over time, the recommended target for LDL-C has become more stringent, moving from 2.6 mmol/l to 1.8 mmol/l in very high-risk patients. It is currently recommended to start high intensity statin treatment immediately after acute coronary syndromes (ACS) to maximally and rapidly reduce LDL-C. The novel treatment options enable the achievement of very low LDL-C levels below 1 mmol/l, with no reported safety issues, in particular with regard to neurocognitive events. However, current evidence supports the use of PCSK9 mAb treatment in ACS patients only after an initial 2-3 month run-up treatment adaptation period with maximally tolerated statin. The use of PCSK9 mAb immediately in the acute phase of ACS (<1 month) remains to be studied. Some data suggest that circulating PCSK9 increases coronary plaque vulnerability, inflammation as well as platelet aggregation in the acute phase of ACS, potentially justifying earlier PSCK9 mAb treatment initiation. As the use of novel treatment combinations in ACS is further explored to widen the perspectives of a more personalized approach for the management of ACS based on individual patient risk profile and baseline LDL-C values, their relative cost-effectiveness will also need to be assessed.

One-Year Efficacy and Safety of Evolocumab in Japanese Patients - A Pooled Analysis From the Open-Label Extension OSLER Studies

BACKGROUND

Evolocumab, a fully human monoclonal antibody against PCSK9, significantly reduced low-density lipoprotein-cholesterol (LDL-C) levels in Japanese patients by up to 76% when administered with a statin. We evaluated the efficacy and safety of 1 year of evolocumab in a pooled analysis of patients from the 12-week YUKAWA studies who continued into the open-label extension (OLE) OSLER studies.Methods and Results:YUKAWA-1 and YUKAWA-2 were conducted in hypercholesterolemic, high-cardiovascular-risk Japanese patients who were receiving statin therapy. Patients completing these studies were eligible for an OLE study. At OLE entry, patients were re-randomized 2:1 to evolocumab+standard of care (SOC) or SOC alone (OSLER-1: evolocumab 420 mg monthly; OSLER-2: evolocumab 140 mg biweekly or 420 mg monthly). A 1-year analysis was performed on patients enrolled from the YUKAWA studies into OSLER. At parent-study baseline (YUKAWA-1 or YUKAWA-2 patients continuing into OSLER), mean (SD) age was 61 (10) years; 39% were female; mean (SD) baseline LDL-C (on statin) was 119.7 (33.0) mg/dL. Overall rates of adverse events were comparable between evolocumab+SOC and SOC alone. In YUKAWA patients receiving evolocumab+SOC, mean (SE) reductions in LDL-C from parent-study baseline to OLE 1 year were 69.1% (1.2%; OSLER-1) and 65.1% (2.2%; OSLER-2).

CONCLUSIONS

In a pooled 1-year analysis of Japanese patients in the ongoing OSLER studies, treatment with evolocumab+SOC was well tolerated and resulted in sustained LDL-C reductions at 1 year.

Estimated burden of cardiovascular disease and value-based price range for evolocumab in a high-risk, secondary-prevention population in the US payer context

AIM

To estimate real-world cardiovascular disease (CVD) burden and value-based price range of evolocumab for a US-context, high-risk, secondary-prevention population.

MATERIALS AND METHODS

Burden of CVD was assessed using the UK-based Clinical Practice Research Datalink (CPRD) in order to capture complete CV burden including CV mortality. Patients on standard of care (SOC; high-intensity statins) in CPRD were selected based on eligibility criteria of FOURIER, a phase 3 CV outcomes trial of evolocumab, and categorized into four cohorts: high-risk prevalent atherosclerotic CVD (ASCVD) cohort (n = 1448), acute coronary syndrome (ACS) (n = 602), ischemic stroke (IS) (n = 151), and heart failure (HF) (n = 291) incident cohorts. The value-based price range for evolocumab was assessed using a previously published economic model. The model incorporated CPRD CV event rates and considered CV event reduction rate ratios per 1 mmol/L reduction in low-density lipoprotein-cholesterol (LDL-C) from a meta-analysis of statin trials by the Cholesterol Treatment Trialists Collaboration (CTTC), i.e. CTTC relationship.

RESULTS

Multiple-event rates of composite CV events (ACS, IS, or coronary revascularization) per 100 patient-years were 12.3 for the high-risk prevalent ASCVD cohort, and 25.7, 13.3, and 23.3, respectively, for incident ACS, IS, and HF cohorts. Approximately one-half (42%) of the high-risk ASCVD patients with a new CV event during follow-up had a subsequent CV event. Combining these real-world event rates and the CTTC relationship in the economic model, the value-based price range (credible interval) under a willingness-to-pay threshold of $150,000/quality-adjusted life-year gained for evolocumab was $11,990 ($9,341-$14,833) to $16,856 ($12,903-$20,678) in ASCVD patients with baseline LDL-C levels ≥70 mg/dL and ≥100 mg/dL, respectively.

CONCLUSION

Real-world CVD burden is substantial. Using the observed CVD burden in CPRD and the CTTC relationship, the cost-effectiveness analysis showed that, accounting for uncertainties, the expected value-based price for evolocumab is higher than its current annual cost, as long as the payer discount off list price is greater than 20%.

Evolocumab lowers LDL-C safely and effectively when self-administered in the at-home setting

Evolocumab has been shown to consistently reduce low-density lipoprotein cholesterol (LDL-C) across populations. The phase 3 studies included administration in the home-use and in-clinic settings but did not specifically evaluate the feasibility of home-use administration. Two clinical studies enrolled patients with hypercholesterolemia or mixed dyslipidemia on statin therapy and with/without ezetimibe received evolocumab in the home-use setting. Patients were randomized to self-administer evolocumab using one of two injection devices biweekly over 6 weeks (autoinjector or prefilled syringe; n = 149; ClinicalTrials.gov, NCT01849497) or monthly over 12 weeks (autoinjector or automated minidoser; n = 164; NCT01879319). The first self-administration occurred in the in-clinic setting, and two more were performed in the at-home setting. Patients were successful in self-administering evolocumab in the home-use setting in approximately 95 % of attempts and experienced LDL-C reductions from baseline to week 6 or the mean of weeks 10 and 12 of approximately 65 %. Rates of successful self-administration and LDL-C reduction were similar across dosing schedules and study devices. Adverse events were similar between randomized groups and generally mild in severity. In two clinical studies, therefore, patients were able to successfully self-administer evolocumab in both the in-clinic and at-home settings regardless of which dosing schedule or device they used.