Efficacy and safety of PCSK9 monoclonal antibodies

Failure of lipid control by PCSK9 inhibitors in compound heterozygous familial hypercholesterolemia complicated with premature myocardial infarction: A case report

Key Clinical Message

A certain level of low-density lipoprotein receptor activity is crucial for the efficacy of PCSK9i. Therapeutic strategies for familial hypercholesterolemia patients should consider drug efficacy, and genetic testing will be helpful.

Abstract

Familial hypercholesterolemia (FH) is a serious autosomal dominant disorder. Managing blood lipids in FH patients poses greater challenges for clinicians. Drug therapy may not always yield satisfactory results, particularly in individuals with low-density lipoprotein receptor (LDLR) negative mutations. Herein, we report a young female harboring an LDLR frameshift mutation. This patient developed xanthomas at 7 months old and underwent several years of treatment involving four classes of lipid-lowering drugs, including PCSK9i. However, the response to drug therapy was limited in this patient and eventually culminated in premature myocardial infarction. The efficacy of PCSK9i depends on the activity of LDLR. The inefficacy of PCSK9i may arise from the extensive mutations which leading to loss of LDLR activity. Therapy plans for these patients should take into account the efficacy of drug therapy. Early genetic testing is crucial for clinicians to make informed decisions regarding therapy options.

Does Genotype Affect the Efficacy of PCSK9 Inhibitors in the Treatment of Familial Hypercholesterolemia?

PURPOSE OF REVIEW

This review discusses whether patients' genotype affects the efficacy of PCSK9 inhibitors in treating familial hypercholesterolemia and how this might influence clinical management.

RECENT FINDINGS

Currently, available evidence consistently demonstrates and is in good agreement that, in general, the LDL-C-lowering effect of PCSK9 inhibitors is similar across genotypes, except for compound heterozygous and homozygous familial hypercholesterolemia (FH). However, it remains to be seen whether the comparable therapeutic effect in lowering LDL-C level also leads to a comparable degree of cardiovascular risk reduction with different genotypes. Generally, the level of LDL-C reduction following PCSK9 inhibitor treatment is similar within different genotypes. Hence, genotype is a less reliable predictor for further LDL-C level reduction on PCSK9 inhibitor therapy, and attention should be given to other external influences, especially for heterozygous FH.

Current Insights on Dyslipidaemia Management for Prevention of Atherosclerotic Cardiovascular Disease: A Malaysian Perspective

Dyslipidaemia is highly prevalent in the Malaysian population and is one of the main risk factors for atherosclerotic cardiovascular disease (ASCVD). Low-density lipoprotein cholesterol (LDL-C) is recognised as the primary target of lipid-lowering therapy to reduce the disease burden of ASCVD. Framingham General CV Risk Score has been validated in the Malaysian population for CV risk assessment. The Clinical Practice Guidelines (CPG) on the management of dyslipidaemia were last updated in 2017. Since its publication, several newer randomised clinical trials have been conducted with their results published in research articles and compared in meta-analysis. This underscores a need to update the previous guidelines to ensure good quality care and treatment for the patients. This review summarises the benefits of achieving LDL-C levels lower than the currently recommended target of < 1.8mmol/L without any safety concerns. In most high and very high-risk individuals, statins are the first line of therapy for dyslipidaemia management. However, certain high-risk individuals are not able to achieve the LDL-C goal as recommended in the guideline even with high-intensity statin therapy. In such individuals, lower LDL-C levels can be achieved by combining the statins with non-statin agents such as ezetimibe and PCSK9 inhibitors. Emerging non-statin lipid-lowering therapies and challenges in dyslipidaemia management are discussed in this article. The review also summarises the recent updates on local and international guidelines for dyslipidaemia management.

PCSK9 inhibition and cholesterol homeostasis in insulin producing β-cells

Low-density lipoprotein cholesterol (LDL-C) plays a central role in the pathology of atherosclerotic cardiovascular disease. For decades, the gold standard for LDL-C lowering have been statins, although these drugs carry a moderate risk for the development of new-onset diabetes. The inhibitors of proprotein convertase subtilisin/kexin type 9 (PCSK9) have emerged in the last years as potential alternatives to statins due to their high efficiency and safety without indications for a diabetes risk so far. Both approaches finally eliminate LDL-C from bloodstream by upregulation of LDL receptor surface expression. Due to their low antioxidant capacity, insulin producing pancreatic β-cells are sensitive to increased lipid oxidation and related generation of reactive oxygen species. Thus, PCSK9 inhibition has been argued to promote diabetes like statins. Potentially, the remaining patients at risk will be identified in the future. Otherwise, there is increasing evidence that loss of circulating PCSK9 does not worsen glycaemia since it is compensated by local PCSK9 expression in β-cells and other islet cells. This review explores the situation in β-cells. We evaluated the relevant biology of PCSK9 and the effects of its functional loss in rodent knockout models, carriers of LDL-lowering gene variants and PCSK9 inhibitor-treated patients.

Blood lipid levels and treatment following an acute coronary syndrome or coronary intervention – Journey from hospital to cardiac rehabilitation

Background

A significant number of coronary artery disease patients do not attain guideline recommended LDL levels. Participating in a cardiac rehabilitation (CR) program has been shown to improve adherence to medical therapy.

Objectives

Evaluate the specific lipid lowering therapy (LLT) prescribed and percent of subjects achieving LDL levels of <70 mg/dL before and after 3 months following CR program initiation.

Methods

From May 2017 to April 2019, we prospectively recruited patients referred to our CR program and compared 1015 of them at 4 time points; (P1) just prior to the index hospitalization, (P2) during the index hospitalization, (P3) upon entering the CR program, roughly 3 months after the index hospitalization, and (P4) 3 months into the CR program. Included in the analysis were parameters of lipid levels, the dispensed medication given, as well as patient adherence to treatment. Results: At CR intake, LDL goals were partially achieved with 57% of patients below 70 mg/dL. After completion of 3 months of CR, 63% of patients had LDL levels below 70 mg/dL, despite the fact that the majority (95%) were prescribed high-dose potent statins. Aside from the LDL levels at CR intake, we found no other independent predictors for not attaining the lipid goals at 6 months.

Conclusions

A significant treatment gap is present even in a selected population participating in CR, with the vast majority receiving guideline recommended LLT. In order to improve goals, we need to intensify LLT treatment, and increase patient adherence to therapy.

ALERT-LDL: adherence to guidelines in the treatment of patients with dyslipidemia

The association between LDL-c levels and cardiovascular outcomes suggests tailoring lipid-lowering therapies according to total cardiovascular risk. We aimed to evaluate the adherence to guidelines-oriented dyslipidaemia's treatment in an outpatient population referring to ARCA cardiologists, and assess the efficacy of treatment's optimization for each specific level of risk. Three thousand seventy-five patients enrolled in this prospective study were classified according to cardiovascular risk category, and their therapies were optimized. At the beginning and the 3 month follow-up visit, LDL-c data were collected, and further therapies were prescribed to the patients that did not reach the target. A significant LDL-c reduction was observed in all subgroups at different cardiovascular risk at the end of the study (p < 0.05). The number of patients assuming statins, both in monotherapy and in combination with ezetimibe, increased during the follow-up (63% at the enrollment vs 89% after 12 months). At the enrollment, only 1.4% of patients were treated with PCSK-9 inhibitors while after 12 months the percentage increased both in high (5.8%) and very high-risk (18.4%) patients. At the beginning of the study, only 698/3075 patients (22.7%) reached lipid targets. At the end of the study, carried out by the referring cardiologists in the pertaining healthcare districts and specifically aimed to control the lipid profile, the percentage of patients on target increased in all risk categories (68.5%). Our results suggest carefully implementing measures that encourage outpatients and their cardiologists to achieve the targeted lipid profile according to cardiovascular risk.

The Clinical Importance of Differentiating Monogenic Familial Hypercholesterolemia from Polygenic Hypercholesterolemia

PURPOSE OF REVIEW

The current review discusses the importance and significance of differentiating monogenic familial hypercholesterolemia (FH) from polygenic hypercholesterolemia for clinical purpose.

RECENT FINDINGS

Consistent scientific evidence have demonstrated that, compared to polygenic hypercholesterolemia, monogenic FH patients are at significantly higher risk for premature coronary heart disease (CHD). This is despite both disease entities having a comparable low-density-lipoprotein cholesterol (LDLC) level. Monogenic FH also has poorer therapeutic response compared to its polygenic counterpart. However, there are no current available clinical management guidelines that stratify hypercholesterolemia patients based on genotype. Monogenic FH patients are at higher risk for CHD with poorer therapeutic response. Thus, genotype testing should be performed when available. There is also an urgency to develop genotype-based clinical guideline that stratify patients on genotype and not only based on traditionally known cardiovascular risk factors.

PCSK9 Imperceptibly Affects Chemokine Receptor Expression In Vitro and In Vivo

Proprotein convertase subtilin/kexin type 9 (PCSK9) is a protease secreted mainly by hepatocytes and in lesser quantities by intestines, pancreas, and vascular cells. Over the years, this protease has gained importance in the field of cardiovascular biology due to its regulatory action on the low-density lipoprotein receptor (LDLR). However, recently, it has also been shown that PCSK9 acts independent of LDLR to cause vascular inflammation and increase the severity of several cardiovascular disorders. We hypothesized that PCSK9 affects the expression of chemokine receptors, major mediators of inflammation, to influence cardiovascular health. However, using overexpression of PCSK9 in murine models in vivo and PCSK9 stimulation of myeloid and vascular cells in vitro did not reveal influences of PCSK9 on the expression of certain chemokine receptors that are known to be involved in the development and progression of atherosclerosis and vascular inflammation. Hence, we conclude that the inflammatory effects of PCSK9 are not associated with the here investigated chemokine receptors and additional research is required to elucidate which mechanisms mediate PCSK9 effects independent of LDLR.

Lipids and peripheral neuropathy

PURPOSE OF REVIEW

Hyperlipidaemia is associated with the development of neuropathy. Indeed, a mechanistic link between altered lipid metabolism and peripheral nerve dysfunction has been demonstrated in a number of experimental and clinical studies. Furthermore, post hoc analyses of clinical trials of cholesterol and triglyceride-lowering pharmacotherapy have shown reduced rates of progression of diabetic neuropathy. Given, there are currently no FDA approved disease-modifying therapies for diabetic neuropathy, modulation of lipids may represent a key therapeutic target for the treatment of diabetic nerve damage. This review summarizes the current evidence base on the role of hyperlipidaemia and lipid lowering therapy on the development and progression of peripheral neuropathy.

RECENT FINDINGS

A body of literature supports a detrimental effect of dyslipidaemia on nerve fibres resulting in somatic and autonomic neuropathy. The case for an important modulating role of hypertriglyceridemia is stronger than for low-density lipoprotein cholesterol (LDL-C) in relation to peripheral neuropathy. This is reflected in the outcomes of clinical trials with the different therapeutic agents targeting hyperlipidaemia reporting beneficial or neutral effects with statins and fibrates. The potential concern with the association between proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor therapy and cognitive decline raised the possibility that extreme LDL-C lowering may result in neurodegeneration. However, studies in murine models and data from small observational studies indicate an association between increased circulating PCSK9 levels and small nerve fibre damage with a protective effect of PCSK9i therapy against small fibre neuropathy. Additionally, weight loss with bariatric surgery leads to an improvement in peripheral neuropathy and regeneration of small nerve fibres measured with corneal confocal microscopy in people with obesity with or without type 2 diabetes. These improvements correlate inversely with changes in triglyceride levels.

SUMMARY

Hyperlipidaemia, particularly hypertriglyceridemia, is associated with the development and progression of neuropathy. Lipid modifying agents may represent a potential therapeutic option for peripheral neuropathy. Post hoc analyses indicate that lipid-lowering therapies may halt the progression of neuropathy or even lead to regeneration of nerve fibres. Well designed randomized controlled trials are needed to establish if intensive targeted lipid lowering therapy as a part of holistic metabolic control leads to nerve fibre regeneration and improvement in neuropathy symptoms.

PCSK9: A Multi-Faceted Protein That Is Involved in Cardiovascular Biology

Pro-protein convertase subtilisin/kexin type 9 (PCSK9) is secreted mostly by hepatocytes and to a lesser extent by the intestine, pancreas, kidney, adipose tissue, and vascular cells. PCSK9 has been known to interact with the low-density lipoprotein receptor (LDLR) and chaperones the receptor to its degradation. In this manner, targeting PCSK9 is a novel attractive approach to reduce hyperlipidaemia and the risk for cardiovascular diseases. Recently, it has been recognised that the effects of PCSK9 in relation to cardiovascular complications are not only LDLR related, but that various LDLR-independent pathways and processes are also influenced. In this review, the various LDLR dependent and especially independent effects of PCSK9 on the cardiovascular system are discussed, followed by an overview of related PCSK9-polymorphisms and currently available and future therapeutic approaches to manipulate PCSK9 expression.

2021 Canadian Cardiovascular Society Guidelines for the Management of Dyslipidemia for the Prevention of Cardiovascular Disease in Adults

The 2021 guidelines primary panel selected clinically relevant questions and produced updated recommendations, on the basis of important new findings that have emerged since the 2016 guidelines. In patients with clinical atherosclerosis, abdominal aortic aneurysm, most patients with diabetes or chronic kidney disease, and those with low-density lipoprotein cholesterol ≥ 5 mmol/L, statin therapy continues to be recommended. We have introduced the concept of lipid/lipoprotein treatment thresholds for intensifying lipid-lowering therapy with nonstatin agents, and have identified the secondary prevention patients who have been shown to derive the largest benefit from intensification of therapy with these agents. For all other patients, we emphasize risk assessment linked to lipid/lipoprotein evaluation to optimize clinical decision-making. Lipoprotein(a) measurement is now recommended once in a patient's lifetime, as part of initial lipid screening to assess cardiovascular risk. For any patient with triglycerides ˃ 1.5 mmol/L, either non-high-density lipoprotein cholesterol or apolipoprotein B are the preferred lipid parameter for screening, rather than low-density lipoprotein cholesterol. We provide updated recommendations regarding the role of coronary artery calcium scoring as a clinical decision tool to aid the decision to initiate statin therapy. There are new recommendations on the preventative care of women with hypertensive disorders of pregnancy. Health behaviour modification, including regular exercise and a heart-healthy diet, remain the cornerstone of cardiovascular disease prevention. These guidelines are intended to provide a platform for meaningful conversation and shared-decision making between patient and care provider, so that individual decisions can be made for risk screening, assessment, and treatment.

Effectiveness, Safety, and Adherence to Treatment of Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitors in Real Practice

PURPOSE

To evaluate the effectiveness, adverse reactions, and adherence to treatment of hypolipidemic inhibitors of proprotein convertase subtilisin/kexin type 9 (PCSK9is) in a context of real clinical practice.

METHODS

We present an observational, retrospective, descriptive, multicenter study of patients with hypercholesterolemia who began treatment with PCSK9is between January 2017 and December 2019, with a minimum treatment period of 3 months. The main variable we recorded was the frequency of cardiovascular events (cardiovascular death, myocardial infarction, stroke, coronary revascularization, and hospitalization for unstable angina) in patients treated with PCSK9is. We recorded patient demographic characteristics and cardiovascular risk factors at onset of treatment as well as LDL-C levels and their reductions at 3, 6, 12, and 24 months. We calculated adherence to treatment and recorded the adverse reactions during treatment.

FINDINGS

A total of 154 patients were studied, 64 (41.6%) of whom were treated with alirocumab and 90 (58.4%) with evolocumab. The initial dose of alirocumab was 75 mg every 14 days in 48 patients (75%) and 150 mg eery 14 days in 16 (25%). All patients who in the evolocumab group received a dose of 140 mg every 14 days. The mean (SD) basal LDL-C level was 159.6 (50.1) mg/dL, the level at 3 months was 87.9 (49.9) mg/dL (mean [SD] decrease, 44.5% [28.2%]), the level at 6 months was 86.7 (49.2) mg/dL (mean [SD] decrease, 46.3% [25.6%]), and the level at 12 months was 80.5 (41.4) (mean [SD] decrease, 48.9% [23.0%]). These values were maintained at 24 months (mean [SD], 80.3 [41.8] mg/dL; mean [SD] decrease, 47.9% [27.8%]). The percentage decrease of LDL-C for both drugs was approximately 50%, which was maintained until 24 months after treatment. Six patients (3.9%) presented with some cardiovascular event: acute myocardial infarction (2 [1.3%]), stroke (1 [0.65%]), coronary revascularization (1 [0.65%]), and hospitalization for unstable angina (2 [1.3%]). We did not see any adverse reactions related to PCSK9i treatment in 76.5% of patients. In the first 6 months, adherence to treatment with PCSK9is, measured as the possession ratio, was a mean (SD) of 99.4% (3.9%). In the rest of the study period (6-24 months), the mean (SD) adherence to treatment was 99.2% (4.7%).

IMPLICATIONS

The frequency of cardiovascular events in patients treated with PCSK9is was low and occurred despite adequate adherence to treatment (100% possession ratio) with PCSK9is and concomitant treatment with other hypolipidemics. The effectiveness of PCSK9is is similar to that referred to in other published studies with PCSK9is, and this was maintained in the long term (24 months) with few adverse events, all of which were mild.

Management of Familial Hypercholesterolemia: Current Status and Future Perspectives

Familial hypercholesterolemia (FH) is the most common monogenic disorder associated with premature atherosclerotic cardiovascular disease. Early diagnosis and effective treatment can significantly improve prognosis. Recent advances in the field of lipid metabolism have shed light on the molecular defects in FH and new therapeutic options have emerged. A search of PubMed database up to March 2020 was performed for this review using the following keywords: "familial hypercholesterolemia," "diagnosis," "management," "guideline," "consensus," "genetics," "screening," "lipid lowering agents." The prevalence rate of heterozygous FH is approximately 1 in 200 to 250 and FH is underdiagnosed and undertreated in many parts of the world. Diagnostic criteria have been developed to aid the clinical diagnosis of FH. Genetic testing is now available but not widely used. Cascade screening is recommended to identify affected family members, and the benefits of early interventions are clear. Treatment strategy and target is currently based on low-density lipoprotein (LDL) cholesterol levels as the prognosis of FH largely depends on the magnitude of LDL cholesterol-lowering that can be achieved by lipid-lowering therapies. Statins with or without ezetimibe are the mainstay of treatment and are cost-effective. Addition of newer medications like PCSK9 inhibitors is able to further lower LDL cholesterol levels substantially, but the cost is high. Lipoprotein apheresis is indicated in homozygous FH or severe heterozygous FH patients with inadequate response to cholesterol-lowering therapies. In conclusion, FH is a common, treatable genetic disorder, and although our understanding of this disease has improved, many challenges still remain for its optimal management.