Cholesterol trials and mortality

Familial Hypercholesterolaemia as a Predisposing Factor for Atherosclerosis

Lipid metabolism alterations are an important component of the pathogenesis of atherosclerosis. However, it is now clear that the atherogenesis process involves more than one mechanism, and more than one condition can predispose this condition. Multiple risk factors contribute to the atherosclerosis initiation and define its course. Familial hypercholesterolaemia is a disorder of lipid metabolism that often leads to atherosclerosis development. As is clear from the disease name, the hallmark is the increased levels of low-density lipoprotein cholesterol (LDL-C) in blood. This creates favourable conditions for atherogenesis. In this review, we briefly described the familial hypercholesterolaemia and summarized data on the relationship between familial hypercholesterolaemia and atherosclerosis.

Roadmap for translating results from the micronucleus assay into clinical practice: From observational studies to randomized controlled trials

According to the definition delivred by the WHO, a biomarker, independently from its role that may be indicative of exposure, response or effect, is inevitably linked to a clinical outcome or to a disease. The presence of a continuum from early biological events to therapy, and prognosis is the unifying mechanism that justifies this conclusion. Traditionally, the technical and inter-individual variability of the assays, together with the long duration between early pathogenetic events and the disease, prevented clinical applications to these biomarkers. These limitations became less important with the emerging of personalized preventive medicine because of the focus on disease prediction and prevention, and the recommended use of all data concerning measurable patient's features. Several papers have been published on the best validation procedures for translating biomarkers to real life. The history of cholesterol concentration is extensively discussed as a reliable example of a biomarker that - after a long and controversial validation process - is currently used in clinical practice. The frequency of micronucleated cells is a reliable biomarker for the pathogenesis of cancer and other non-communicable diseases, and the link with clinical outcomes is substantiated by epidemiological evidence and strong mechanistic basis. Available literature concerning the use of the micronucleus assay in clinical studies is discussed, and a suitable three-levels road-map driving this biomarker towards clinical practice is presented. Under the perspective of personalized medicine, the use of the micronucleus assays can play a decisive role in addressing preventive and therapeutic strategies of chronic diseases. In many cases the MN assay is either currently used in clinical practice or classified as adequate to consider translation into practice. The roadmap to clinical validation of the micronucleus assay finds inspiration from the history of biomarkers such as cholesterol, which clearly showed that the evidence from prospective studies or RCTs is critical to achieve the required level of trust from the healthcare profession. (307 words).

Atherosclerosis: Conventional intake of cardiovascular drugs versus delivery using nanotechnology - A new chance for causative therapy?

Atherosclerosis is the leading cause of death in developed countries. The pathogenetic mechanism relies on a macrophage-based immune reaction to low density lipoprotein (LDL) deposition in blood vessels with dysfunctional endothelia. Thus, atherosclerosis is defined as a chronic inflammatory disease. A plethora of cardiovascular drugs have been developed and are on the market, but the major shortcoming of standard medications is that they do not address the root cause of the disease. Statins and thiazolidinediones that have recently been recognized to exert specific anti-atherosclerotic effects represent a potential breakthrough on the horizon. But their whole potential cannot be realized due to insufficient availability at the pathological site and severe off-target effects. The focus of this review will be to elaborate how both groups of drugs could immensely profit from nanoparticulate carriers. This delivery principle would allow for their accumulation in target macrophages and endothelial cells of the atherosclerotic plaque, increasing bioavailability where it is needed most. Based on the analyzed literature we conclude design criteria for the delivery of statins and thiazolidinediones with nanoparticles for anti-atherosclerotic therapy. Nanoparticles need to be below a diameter of 100 nm to accumulate in the atherosclerotic plaque and should be fabricated using biodegradable materials. Further, the thiazolidinediones or statins must be encapsulated into the particle core, because especially for thiazolidindiones the uptake into cells is prerequisite for their mechanism of action. For optimal uptake into targeted macrophages and endothelial cells, the ideal particle should present ligands on its surface which bind specifically to scavenger receptors. The impact of statins on the lectin-type oxidized LDL receptor 1 (LOX1) seems particularly promising because of its outstanding role in the inflammatory process. Using this pioneering concept, it will be possible to promote the impact of statins and thiazolidinediones on macrophages and endothelial cells and significantly enhance their anti-atherosclerotic therapeutic potential.

Translating the dose response into risk and benefit

When choosing a medicine two aspects determine the balance between benefit and harm (risk-benefit), matching the medicine to the individual and the choice of dose. Knowing the relationship between dose and response allows a calculation of the dose that causes 50% of the maximal effect, the ED₅₀ . Rational drug dosing depends on defining the ratio of the dose to the ED₅₀ . The ED₅₀ of each drug has two scales, whether the effect measured is for efficacy, or safety. Quantifying efficacy is comparatively straightforward. A fall in blood pressure, combined with a statistical and clinically significant reduction in cardiovascular events, might justify the efficacy of an antihypertensive. Measuring a drug's effect on safety is more complex, as this is so often a subjective assessment of a collection of adverse events. Though a science-based therapeutic window defined from in vitro efficacy and safety dose response curves is reassuring, this review discusses how to translate this into dose-dependent risk-benefit based on clinical trial data. Some of the limitations of our knowledge about the choice of dose that optimizes an individual's risk-benefit, or whether no drug is a better option, are discussed. It is important to define these limitations when educating the consumer/patient about the clinical pharmacology that justifies their treatment dose options.

The pharmacodynamic and clinical trial evidence for statin dose

Statin doses around estimated effective dose 50 (ED50) can reduce myocardial infarction by over 25% and mortality by around 10%. Being a competitive enzyme inhibitor, statin efficacy plateaus at doses that are multiples above the ED50, whilst on- and off-target adverse events increase in number and severity with increasing dose. For example, myopathy has been shown to increase by up to 29-fold and liver dysfunction by up to nine-fold as statin dose is increased. Doses of up to 40-fold ED50 have been promoted, but above five-fold ED50, for example 10 mg of atorvastatin, there is no randomized controlled clinical trial evidence that coronary mortality is lowered, or that survival is increased.

Disconnect Between Genes Associated With Ischemic Heart Disease and Targets of Ischemic Heart Disease Treatments

Background

Development of pharmacological treatments to mitigate ischemic heart disease (IHD) has encompassed disappointing results and expensive failures, which has discouraged investment in new approaches to prevention and control. New treatments are most likely to be successful if they act on genetically validated targets. We assessed whether existing pharmacological treatments for IHD reduction are acting on genetically validated targets and whether all such targets for IHD are currently being exploited.

Methods

Genes associated with IHD were obtained from the loci of single nucleotide polymorphisms reported in either of two recent genome wide association studies supplemented by a gene-based analysis (accounting for linkage disequilibrium) of CARDIoGRAMplusC4D 1000 Genomes, a large IHD case (n = 60,801)-control (n = 123,504) study. Treatments targeting the products of these IHD genes and genes with products targeted by current IHD treatments were obtained from Kyoto Encyclopedia of Genes and Genomes and Drugbank. Cohen's kappa was used to assess agreement.

Results

We identified 173 autosomal genes associated with IHD and 236 autosomal genes with products targeted by current IHD treatments, only 8 genes (PCSK9, EDNRA, PLG, LPL, CXCL12, LRP1, CETP and ADORA2A) overlapped, i.e. were both associated with IHD and had products targeted by current IHD treatments. The Cohen's kappa was 0.03. Interventions related to another 29 IHD genes exist, including dietary factors, environmental exposures and existing treatments for other indications.

Conclusions

Closer alignment of IHD treatments with genetically validated physiological targets may represent a major opportunity for combating a leading cause of global morbidity and mortality through repurposing existing interventions.

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Pharmacological treatments for ischemic heart disease (IHD) target < 5% (8/173) of genes strongly predicting IHD.

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Treatments or nutraceuticals targeting products of another 17% (29/173) of genes strongly predicting IHD exist.

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Repurposing represents a major opportunity to prevent and treat a leading cause of global morbidity and mortality.

Development of drugs to mitigate ischemic heart disease, a leading cause of global morbidity and mortality, has stalled. We examined the relation between the physiological targets of current drugs for ischemic heart disease and the genetic predictors of ischemic heart disease. We found little correspondence between the genes with products targeted by current ischemic heart disease drugs and the genes associated with ischemic heart disease, but found several drugs for other purposes relevant to ischemic heart disease genes. Refocusing ischemic heart disease drug development on genetically valid targets and repurposing existing drugs represents a major opportunity to improve population health.

Long-term efficacy and safety of proprotein convertase subtilisin/kexin 9 monoclonal antibodies: A meta-analysis of 11 randomized controlled trials

BACKGROUND

Monoclonal antibodies targeting proprotein convertase subtilisin/kexin type 9 (PCSK9) have been shown to significantly reduce low-density lipoprotein cholesterol (LDL-C) levels.

OBJECTIVE

The purpose of this study was to assess the long-term efficacy and safety of PCSK9 antibodies.

METHODS

PubMed, EMBASE, the Cochrane Library, and ClinicalTrials.gov were searched for relevant studies.

RESULTS

A total of 11 studies including 38,235 participants who were treated for at least 48 weeks were included in this meta-analysis. The results suggested that PCSK9 antibody treatment significantly decreased LDL-C levels (mean difference, -50.23% [95% confidence interval {CI}, -56.65% to -43.82%]) compared with no PCSK9 antibody treatment and also decreased other atherogenic lipid fractions. PCSK9 antibody treatment also elicited a significant reduction in cardiovascular event rates compared with no antibody treatment (relative risk [RR], 0.86 [95% CI, 0.81-0.92]). This reduction consisted of separate significant reductions in the rates of myocardial infarction (RR, 0.73 [95% CI, 0.65-0.82]), coronary revascularization (RR, 0.79 [95% CI, 0.73-0.87]), and stroke (RR, 0.81 [95% CI, 0.68-0.96]). There were no clear differences in the incidences of treatment-emergent adverse events (TEAEs), serious TEAEs, or TEAEs of interest between the 2 groups; moreover, no differences between the 2 groups were found for other laboratory parameters.

CONCLUSION

PCSK9 antibodies have significant effects on reducing LDL-C levels and improve cardiovascular outcomes. These antibodies have a satisfactory safety profile, which suggests that they are suitable for use as a long-term treatment.

Statins and mortality: the untold story

Statins are first-line evidence-based drugs for the management of dyslipidaemias and to reduce the risk of cardiovascular events. However, statin clinical trials have shown marginally significant benefits on mortality, especially in the primary prevention setting. A major limitation of those trials is their relatively short follow-up. A reduced number of fatal events within a 5-year follow-up make mortality benefits unlikely to arise. This is particularly relevant for the primary prevention trials, where the risk of cardiovascular death is low. The short follow-up is a limitation for safety assessments too. However, extended major statin trials failed to detect any major safety concerns. Safety and efficacy assessments are even more complicated considering the differences of cardiovascular risk status in primary prevention individuals, and also given some potential ethnic and inter-individual genetic variations in response to statin treatment. Considerable evidence suggests a favourable risk-benefit balance for statin treatment. It can be assumed that statins reduce mortality in the long term by preventing cardiovascular events with complications that reduce lifespan. Unfortunately, this hypothesis cannot be proven as there is no current ethical basis on designing long-term placebo-controlled statin trials. Nevertheless, by effectively reducing disabilities related to cardiovascular events, statins have major benefits for public health. Therefore, clinicians should not withhold statin treatment awaiting proof of mortality benefits, as this may remain an 'untold story'.

Cholesterol trials and mortality

An overview of clinical trials can reveal a class effect on mortality that is not apparent from individual trials. Most large trials of lipid pharmacotherapy are not powered to detect differences in mortality and instead assess efficacy with composite cardiovascular endpoints. We illustrate the importance of all-cause mortality data by comparing survival in three different sets of the larger controlled lipid trials that underpin meta-analyses. These trials are for fibrates and statins. Fibrate treatment in five of the six main trials was associated with a decrease in survival, one fibrate trial showed a non-significant reduction in mortality that can be explained by a different target population. In secondary prevention, statin treatment increased survival in all five of the main trials, absolute mean increase ranged from 0.43% to 3.33%, the median change was 1.75%, which occurred in the largest trial. In primary prevention, statin treatment increased survival in six of the seven main trials, absolute mean change in survival ranged from -0.09% to 0.89%, median 0.49%. Composite safety endpoints are rare in these trials. The failure to address composite safety endpoints in most lipid trials precludes a balanced summary of risk-benefit when a composite has been used for efficacy. Class effects on survival provide informative summaries of the risk-benefit of lipid pharmacotherapy. We consider that the presentation of key mortality/survival data adds to existing meta-analyses to aid personal treatment decisions.