Pharmacogenomic determinants of the cardiovascular effects of dalcetrapib

ADCY9 Genetic Variants and Cardiovascular Outcomes With Evacetrapib in Patients With High-Risk Vascular Disease: A Nested Case-Control Study

Importance

A pharmacogenetic analysis of dalcetrapib, a cholesteryl ester transfer protein inhibitor, reported an association between a single-nucleotide polymorphism (SNP) in the ADCY9 gene (rs1967309) and reduction in major adverse cardiovascular events despite a neutral result for the overall trial.

Objective

To determine whether the association between the SNP in the ADCY9 gene and a reduction in major adverse cardiovascular events could be replicated for another cholesteryl ester transfer protein inhibitor, evacetrapib, in patients with high-risk vascular disease.

Design, Setting, and Participants

A nested case-control study examining the rs1967309 SNP in 1427 cases and 1532 matched controls selected from the 12 092-patient Assessment of Clinical Effects of Cholesteryl Ester Transfer Protein Inhibition with Evacetrapib in Patients at a High Risk for Vascular Outcomes (ACCELERATE) trial, a randomized, double-blind, placebo-controlled phase 3 trial conducted in patients with high-risk vascular disease randomized from October 2012 through December 2013. The genotyping was conducted from January 2017 to March 2017, and the data analyses were conducted from July 2017 to November 2017.

Exposures

Evacetrapib, 130 mg, or matching placebo.

Main Outcomes and Measures

The primary analyses used a conditional logistic regression model to assess the odds ratio (OR) for major adverse cardiovascular events for evacetrapib compared with placebo for each genotype. The basic model included adjustment for age, sex, and the top 5 principal components. An additional model included cardiovascular risk factors to adjust for potential bias in selecting control patients. The primary major adverse cardiovascular event end point was the composite of death from cardiovascular causes, myocardial infarction, stroke, coronary revascularization, or hospitalization for unstable angina.

Results

For patients with the AA genotype reported to demonstrate a beneficial effect from dalcetrapib, the OR for evacetrapib compared with placebo was 0.88 (95% CI, 0.69-1.12). For patients with the AG genotype, the OR was 1.04 (95% CI, 0.90-1.21). For patients with the GG genotype reported to show evidence for a harmful effect from dalcetrapib, the OR for evacetrapib was 1.18 (95% CI, 0.98-1.41). The interaction P value among the 3 genotypes was P = .17 and the trend P value was P = .06. When adjusted for cardiovascular risk factors, the OR for evacetrapib was 0.93 (95% CI, 0.73-1.19) for the AA genotype, 1.05 (95% CI, 0.91-1.22) for the AG genotype, and 1.02 (95% CI 0.85-1.24) for the GG genotype; interaction P = .71 and trend P = .59.

Conclusions and Relevance

Pharmacogenetic analysis did not show a significant association between the ADCY9 SNP (rs1967309) and cardiovascular benefit or harm for the cholesteryl ester transfer protein inhibitor evacetrapib.

New Therapeutic Approaches for Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is a common genetic condition characterized by elevated plasma levels of low-density lipoprotein cholesterol (LDL-C), premature atherosclerotic cardiovascular disease, and considerable unmet medical need with conventional LDL-C-lowering therapies. Between 2012 and 2015, the US Food and Drug Administration approved four novel LDL-C-lowering agents for use in patients with FH based on the pronounced LDL-C-lowering efficacy of these medicines. We review the four novel approved agents, as well as promising LDL-C-lowering agents in clinical development, with a focus on their mechanism of action, efficacy in FH cohorts, and safety.

Impact of ADCY9 Genotype on Response to Anacetrapib

BACKGROUND

Exploratory analyses of previous randomized trials generated a hypothesis that the clinical response to cholesteryl ester transfer protein (CETP) inhibitor therapy differs by ADCY9 genotype, prompting the ongoing dal-GenE trial in individuals with a particular genetic profile. The randomized placebo-controlled REVEAL trial (Randomized Evaluation of the Effects of Anacetrapib through Lipid-Modification) demonstrated the clinical efficacy of the CETP inhibitor anacetrapib among patients with preexisting atherosclerotic vascular disease. In the present study, we examined the impact of ADCY9 genotype on response to anacetrapib in the REVEAL trial.

METHODS

Individuals with stable atherosclerotic vascular disease who were treated with intensive atorvastatin therapy received either anacetrapib 100 mg daily or matching placebo. Cox proportional hazards models, adjusted for the first 5 principal components of ancestry, were used to estimate the effects of allocation to anacetrapib on major vascular events (a composite of coronary death, myocardial infarction, coronary revascularization, or presumed ischemic stroke) and the interaction with ADCY9 rs1967309 genotype.

RESULTS

Among 19 210 genotyped individuals of European ancestry, 2504 (13.0%) had a first major vascular event during 4 years median follow-up: 1216 (12.6%) among anacetrapib-allocated participants and 1288 (13.4%) among placebo-allocated participants. Proportional reductions in the risk of major vascular events with anacetrapib did not differ significantly by ADCY9 genotype: hazard ratio (HR) = 0.92 (95% CI, 0.81-1.05) for GG; HR = 0.94 (95% CI, 0.84-1.06) for AG; and HR = 0.93 (95% CI, 0.76-1.13) for AA genotype carriers, respectively; genotypic P for interaction = 0.96. Furthermore, there were no associations between ADCY9 genotype and the proportional reductions in the separate components of major vascular events or meaningful differences in lipid response to anacetrapib.

CONCLUSIONS

The REVEAL trial is the single largest study to date evaluating the ADCY9 pharmacogenetic interaction. It provides no support for the hypothesis that ADCY9 genotype is materially relevant to the clinical effects of the CETP inhibitor anacetrapib. The ongoing dal-GenE study will provide direct evidence as to whether there is any specific pharmacogenetic interaction with dalcetrapib.

CLINICAL TRIAL REGISTRATION

URL: https://www.

CLINICALTRIALS

gov. Unique identifier: NCT01252953. URL: http://www.isrctn.com. Unique identifier: ISRCTN48678192. URL: https://www.clinicaltrialsregister.eu. Unique identifier: 2010-023467-18.

Opportunities and Challenges in Cardiovascular Pharmacogenomics: From Discovery to Implementation

This review will provide an overview of the principles of pharmacogenomics from basic discovery to implementation, encompassing application of tools of contemporary genome science to the field (including areas of apparent divergence from disease-based genomics), a summary of lessons learned from the extensively studied drugs clopidogrel and warfarin, the current status of implementing pharmacogenetic testing in practice, the role of genomics and related tools in the drug development process, and a summary of future opportunities and challenges.

Lipid transfer to high-density lipoproteins in coronary artery disease patients with and without previous cerebrovascular ischemic events

BACKGROUND

Patients with coronary artery disease (CAD) and previous ischemic cerebrovascular events (ICVE, ischemic stroke, or transitory ischemic attack) constitute a high-risk subgroup for cardiovascular outcomes. High-density lipoprotein cholesterol (HDL-C) levels are correlated with cardiovascular events. Lipid transfer to HDL affects structure size and HDL subclass profile. Impairment of this transfer could influence ischemic risk seen in patients with CAD + ICVE. The objective was to evaluate the HDL ability to receive the lipids in patients with CAD with or without ICVE.

METHODS

Patients with CAD + ICVE (n = 60) and patients with CAD only (n = 60) were matched by age, sex, acute coronary syndromes (ACS) event type, and time elapsed between the ACS event and inclusion in the study. Lipid transfer to HDL was evaluated by incubating donor lipid nanoparticles labeled with radioactive unesterified cholesterol (UC) and esterified cholesterol (EC), phospholipid (PL), and triglyceride (TG) with whole plasma. After the chemical precipitation of non-HDL fractions and nanoparticles, the supernatant was counted for HDL radioactivity.

RESULTS

CAD + ICVE group presented with impaired lipid transfer to HDL for PL (CAD + ICVE: 21.14 ± 2.7% vs CAD: 21.67 ± 3.1%, P = .03), TG (CAD + ICVE: 4.88 ± 0.97% vs CAD: 5.63 ± 0.92%, P = .002), and UC (CAD + ICVE: 5.55 ± 1.19% vs CAD: 6.16 ± 1.14%, P = .009). Lipid transfer to HDL was similar in both groups for EC. Adjusted models showed similar results.

CONCLUSION

Patients with CAD and ICVE have reduced lipid transfer to HDL compared to those with CAD only. Dysfunctional HDL may account for the higher incidence of ischemic outcomes observed in this population.

Pharmacogenomics

Genomic medicine, which uses DNA variation to individualise and improve human health, is the subject of this Series of papers. The idea that genetic variation can be used to individualise drug therapy-the topic addressed here-is often viewed as within reach for genomic medicine. We have reviewed general mechanisms underlying variability in drug action, the role of genetic variation in mediating beneficial and adverse effects through variable drug concentrations (pharmacokinetics) and drug actions (pharmacodynamics), available data from clinical trials, and ongoing efforts to implement pharmacogenetics in clinical practice.

Is hypertriglyceridemia atherogenic?

PURPOSE OF REVIEW

Hypertriglyceridemia occurs mainly because of metabolic disorders secondary to diabetes, alcohol intake, and/or overweight. Genetic factors have also been clearly identified in most severe cases. Triglycerides are generally considered as 'bystanders' for cardiovascular diseases. However, biological and basic research provides strong data suggesting that triglyceride-rich lipoproteins could be involved in the pathophysiology of cardiovascular diseases.

RECENT FINDINGS

The REDUCE-IT trial recently showed that icosapent ethyl reduces major cardiovascular events and related death.

SUMMARY

For many years, low-density lipoproteins (LDLs) have been considered the Holy Grail for atherosclerotic cardiovascular disease management. New data from basic research in biology, epidemiology, genetics, and preliminary clinical trials support the hypothesis that triglyceride-rich lipoproteins could be the causal factors for atherosclerotic cardiovascular disease; hence, triglyceride should be taken into consideration in the management of these patients. Omega-3-fatty acids used in the REDUCE-IT trial reduced the residual cardiovascular risk efficiently beyond statins. However, its effect has to be completely understood as it seems to be unrelated to LDLc or triglyceride reduction, but linked to pleiotropic effects involving inflammation, platelet adhesion, and plaque instability reduction, paving the way for trials that will target more specific potential pathophysiologic pathways.

Do Cholesteryl Ester Transfer Protein Inhibitors Have a Role in the Treatment of Cardiovascular Disease?

Cholesteryl ester transfer protein (CETP) plays an important role in lipid metabolism and has presented an attractive target for drug development, primarily resting on the hope that CETP inhibition would reduce cardiovascular events through its ability to increase levels of high-density lipoprotein cholesterol (HDL-C). However, clinical development of CETP inhibitors has proven disappointing, with a spectrum of results spanning from evidence of harm, to futility, to only modest benefit in large-scale cardiovascular outcomes trials. A number of additional insights from genomic studies have suggested potential benefits from these agents in specific clinical settings. We review the current state of CETP inhibitors as an approach to targeting cardiovascular risk.

HDL: Fact, fiction, or function? HDL cholesterol and cardiovascular risk

The measurement of high-density lipoprotein cholesterol is highly utilized by clinicians to help predict cardiovascular risk, but this measure is not causally associated with atherosclerotic cardiovascular disease events. The use of Mendelian randomization studies has led to a change in investigative attention from the high-density lipoprotein cholesterol concentration to its physiological functions. High-density lipoprotein plays key roles in important pathways related to the development of atherosclerotic disease including reverse cholesterol transport, oxidation and inflammation, and endothelial function as well as in other physiological systems including immune system modulation, cellular apoptosis, and endothelial progenitor cell homeostasis. The identification of dysfunctional high-density lipoprotein may better predict future cardiovascular events compared to numerical high-density lipoprotein cholesterol and aid in enhanced clinical risk stratification. The emergence of discrete physiological measurements of high-density lipoprotein, such as cholesterol efflux capacity and the high-density lipoprotein inflammatory index, may provide an opportunity for clinical application in the future. However, the validity of these measurements and their commercial availability remain barriers to a realistic transition to clinical medicine.

Tackling Residual Atherosclerotic Risk in Statin-Treated Adults: Focus on Emerging Drugs

Epidemiological studies and meta-analyses have consistently suggested the importance of lowering low-density lipoprotein cholesterol (LDL-C) to reduce cardiovascular (CV) events. However, these studies and mechanistic studies using intracoronary imaging modalities have reported patients who continue to experience CV events or disease progression despite optimal LDL-C levels on statins. These findings, including statin intolerance, have highlighted the importance of exploring additional potential therapeutic targets to reduce CV risk. Genomic insights have presented a number of additional novel targets in lipid metabolism. In particular, proprotein convertase subtilisin/kexin type 9 inhibitors have rapidly developed and recently demonstrated their beneficial impact on CV outcomes. Triglyceride (TG)-rich lipoproteins have been recently reported as a causal factor of atherosclerotic cardiovascular disease (ASCVD). Indeed, several promising TG-targeting therapies are being tested at various clinical stages. In this review, we present the evidence to support targeting atherogenic lipoproteins to target residual ASCVD risk in statin-treated patients.

From HDL-cholesterol to HDL-function: cholesterol efflux capacity determinants

PURPOSE OF REVIEW

The validity of HDL-cholesterol (HDL-C) elevation as a therapeutic target has been questioned, in comparison to enhancing HDL functionality. Cholesterol efflux capacity (CEC) is an in-vitro assay that measures the ability of an individual's HDL to promote cholesterol efflux from cholesterol donor cells such as macrophages. CEC of HDL is a predictor of cardiovascular risk independent of HDL-C levels. However, molecular determinants of CEC and the effects of diseases and therapeutic interventions on CEC have not been completely defined.

RECENT FINDINGS

We review here recent findings on elevated HDL-C and disease risk, as well as determinants of CEC, from genetics and proteomics to pathophysiology and therapeutic interventions that contribute to our understanding of CEC as a biomarker of HDL functionality.

SUMMARY

Elevated HDL-C levels are not always protective against cardiovascular disease and mortality. CEC is a heritable trait, and genetic polymorphisms in genes involved in HDL and triglycerides metabolism are associated with CEC. Multiple HDL proteins correlate positively with CEC levels and inversely with noncalcified plaque burden. Differences in CEC assays that make comparisons between studies difficult are also emphasized. CEC should be measured in clinical trials of lipid-modifying and anti-inflammatory therapies to determine whether increases are cardioprotective.

HDL and cardiovascular disease

High-density lipoprotein (HDL) has received increasing interest due to observations of an inverse relationship between its systemic levels and cardiovascular risk and targeted interventions in animal models that have had favourable effects on atherosclerotic plaque. In addition to its pivotal role in reverse cholesterol transport, HDL has been reported to possess a range of functional properties, which may exert a protective influence on inflammation, oxidation, angiogenesis and glucose homeostasis. This has led to the development of a range of HDL targeted therapeutics, which have undergone evaluation in clinical trials. The current state of HDL in cardiovascular prevention will be reviewed.

Epigenetics and precision medicine in cardiovascular patients: from basic concepts to the clinical arena

Cardiovascular diseases (CVDs) remain the leading cause of mortality worldwide and also inflict major burdens on morbidity, quality of life, and societal costs. Considering that CVD preventive medications improve vascular outcomes in less than half of patients (often relative risk reductions range from 12% to 20% compared with placebo), precision medicine offers an attractive approach to refine the targeting of CVD medications to responsive individuals in a population and thus allocate resources more wisely and effectively. New tools furnished by advances in basic science and translational medicine could help achieve this goal. This approach could reach beyond the practitioners 'eyeball' assessment or venerable markers derived from the physical examination and standard laboratory evaluation. Advances in genetics have identified novel pathways and targets that operate in numerous diseases, paving the way for 'precision medicine'. Yet the inherited genome determines only part of an individual's risk profile. Indeed, standard genomic approaches do not take into account the world of regulation of gene expression by modifications of the 'epi'genome. Epigenetic modifications defined as 'heritable changes to the genome that do not involve changes in DNA sequence' have emerged as a new layer of biological regulation in CVD and could advance individualized risk assessment as well as devising and deploying tailored therapies. This review, therefore, aims to acquaint the cardiovascular community with the rapidly advancing and evolving field of epigenetics and its implications in cardiovascular precision medicine.

Systematic Review for the 2018 AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Blood Cholesterol: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines

BACKGROUND

The 2013 American College of Cardiology/American Heart Association guidelines for the treatment of blood cholesterol found little evidence to support the use of nonstatin lipid-modifying medications to reduce atherosclerotic cardiovascular disease (ASCVD) events. Since publication of these guidelines, multiple randomized controlled trials evaluating nonstatin lipid-modifying medications have been published.

METHODS

We performed a systematic review to assess the magnitude of benefit and/or harm from additional lipid-modifying therapies compared with statins alone in individuals with known ASCVD or at high risk of ASCVD. We included data from randomized controlled trials with a sample size of >1 000 patients and designed for follow-up >1 year. We performed a comprehensive literature search and identified 10 randomized controlled trials for intensive review, including trials evaluating ezetimibe, niacin, cholesterol-ester transfer protein inhibitors, and PCSK9 inhibitors. The prespecified primary outcome for this review was a composite of fatal cardiovascular events, nonfatal myocardial infarction, and nonfatal stroke.

RESULTS

The cardiovascular benefit of nonstatin lipid-modifying therapies varied significantly according to the class of medication. There was evidence for reduced ASCVD morbidity with ezetimibe and 2 PSCK9 inhibitors. Reduced ASCVD mortality rate was reported for 1 PCSK9 inhibitor. The use of ezetimibe/simvastatin versus simvastatin in IMPROVE-IT (Improved Reduction of Outcomes: Vytorin Efficacy International Trial) reduced the primary outcome by 1.8% over 7 years (hazard ratio: 0.90; 95% CI: 0.84-0.96], 7-year number needed to treat: 56). The PSCK9 inhibitor evolocumab in the FOURIER study (Further Cardiovascular Outcomes Research with PCSK9 Inhibition in Subjects with Elevated Risk) decreased the primary outcome by 1.5% over 2.2 years (hazard ratio: 0.80; 95% CI: 0.73-0.88; 2.2=year number needed to treat: 67). In ODYSSEY OUTCOMES (Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab), alirocumab reduced the primary outcome by 1.6% over 2.8 years (hazard ratio: 0.86; 95% CI: 0.79-0.93; 2.8-year number needed to treat: 63). For ezetimibe and the PSCK9 inhibitors, rates of musculoskeletal, neurocognitive, gastrointestinal, or other adverse event risks did not differ between the treatment and control groups. For patients at high risk of ASCVD already on background statin therapy, there was minimal evidence for improved ASCVD risk or adverse events with cholesterol-ester transfer protein inhibitors. There was no evidence of benefit for the addition of niacin to statin therapy. Direct comparisons of the results of the 10 randomized controlled trials were limited by significant differences in sample size, duration of follow-up, and reported primary outcomes.

CONCLUSIONS

In a systematic review of the evidence for adding nonstatin lipid-modifying therapies to statins to reduce ASCVD risk, we found evidence of benefit for ezetimibe and PCSK9 inhibitors but not for niacin or cholesterol-ester transfer protein inhibitors.

Systematic Review for the 2018 AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Blood Cholesterol: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines

BACKGROUND

The 2013 American College of Cardiology/American Heart Association guidelines for the treatment of blood cholesterol found little evidence to support the use of nonstatin lipid-modifying medications to reduce atherosclerotic cardiovascular disease (ASCVD) events. Since publication of these guidelines, multiple randomized controlled trials evaluating nonstatin lipid-modifying medications have been published.

METHODS

We performed a systematic review to assess the magnitude of benefit and/or harm from additional lipid-modifying therapies compared with statins alone in individuals with known ASCVD or at high risk of ASCVD. We included data from randomized controlled trials with a sample size of >1,000 patients and designed for follow-up >1 year. We performed a comprehensive literature search and identified 10 randomized controlled trials for intensive review, including trials evaluating ezetimibe, niacin, cholesterol-ester transfer protein inhibitors, and PCSK9 inhibitors. The prespecified primary outcome for this review was a composite of fatal cardiovascular events, nonfatal myocardial infarction, and nonfatal stroke.

RESULTS

The cardiovascular benefit of nonstatin lipid-modifying therapies varied significantly according to the class of medication. There was evidence for reduced ASCVD morbidity with ezetimibe and 2 PSCK9 inhibitors. Reduced ASCVD mortality rate was reported for 1 PCSK9 inhibitor. The use of ezetimibe/simvastatin versus simvastatin in IMPROVE-IT (Improved Reduction of Outcomes: Vytorin Efficacy International Trial) reduced the primary outcome by 1.8% over 7 years (hazard ratio: 0.90; 95% CI: 0.84-0.96], 7-year number needed to treat: 56). The PSCK9 inhibitor evolocumab in the FOURIER study (Further Cardiovascular Outcomes Research with PCSK9 Inhibition in Subjects with Elevated Risk) decreased the primary outcome by 1.5% over 2.2 years (hazard ratio: 0.80; 95% CI: 0.73-0.88; 2.2=year number needed to treat: 67). In ODYSSEY OUTCOMES (Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab), alirocumab reduced the primary outcome by 1.6% over 2.8 years (hazard ratio: 0.86; 95% CI: 0.79-0.93; 2.8-year number needed to treat: 63). For ezetimibe and the PSCK9 inhibitors, rates of musculoskeletal, neurocognitive, gastrointestinal, or other adverse event risks did not differ between the treatment and control groups. For patients at high risk of ASCVD already on background statin therapy, there was minimal evidence for improved ASCVD risk or adverse events with cholesterol-ester transfer protein inhibitors. There was no evidence of benefit for the addition of niacin to statin therapy. Direct comparisons of the results of the 10 randomized controlled trials were limited by significant differences in sample size, duration of follow-up, and reported primary outcomes.

CONCLUSIONS

In a systematic review of the evidence for adding nonstatin lipid-modifying therapies to statins to reduce ASCVD risk, we found evidence of benefit for ezetimibe and PCSK9 inhibitors but not for niacin or cholesterol-ester transfer protein inhibitors.

Current and Emerging Reconstituted HDL-apoA-I and HDL-apoE Approaches to Treat Atherosclerosis

Atherosclerosis affects millions of people worldwide. However, the wide variety of limitations in the current therapeutic options leaves much to be desired in future lipid-lowering therapies. For example, although statins, which are the first-line treatment for coronary heart disease (CHD), reduce the risk of cardiovascular events in a large percentage of patients, they lead to optimal levels of low density lipoprotein-cholesterol (LDL-C) in only about one-third of patients. A new promising research direction against atherosclerosis aims to improve lipoprotein metabolism. Novel therapeutic approaches are being developed to increase the levels of functional high density lipoprotein (HDL) particles. This review aims to highlight the atheroprotective potential of the in vitro synthesized reconstituted HDL particles containing apolipoprotein E (apoE) as their sole apolipoprotein component (rHDL-apoE). For this purpose, we provide: (1) a summary of the atheroprotective properties of native plasma HDL and its apolipoprotein components, apolipoprotein A-I (apoA-I) and apoE; (2) an overview of the anti-atherogenic functions of rHDL-apoA-I and apoA-I-containing HDL, i.e., natural HDL isolated from transgenic Apoa1^−/− × Apoe^−/− mice overexpressing human apoA-I (HDL-apoA-I); and (3) the latest developments and therapeutic potential of HDL-apoE and rHDL-apoE. Novel rHDL formulations containing apoE could possibly present enhanced biological functions, leading to improved therapeutic efficacy against atherosclerosis.

The use of mechanistic evidence in drug approval

The role of mechanistic evidence tends to be under-appreciated in current evidence-based medicine (EBM), which focusses on clinical studies, tending to restrict attention to randomized controlled studies (RCTs) when they are available. The EBM+ programme seeks to redress this imbalance, by suggesting methods for evaluating mechanistic studies alongside clinical studies. Drug approval is a problematic case for the view that mechanistic evidence should be taken into account, because RCTs are almost always available. Nevertheless, we argue that mechanistic evidence is central to all the key tasks in the drug approval process: in drug discovery and development; assessing pharmaceutical quality; devising dosage regimens; assessing efficacy, harms, external validity, and cost-effectiveness; evaluating adherence; and extending product licences. We recommend that, when preparing for meetings in which any aspect of drug approval is to be discussed, mechanistic evidence should be systematically analysed and presented to the committee members alongside analyses of clinical studies.

Is hypertriglyceridemia atherogenic?

ASCVD reduction is based on LDL reduction, especially by statins. Highly elevated TG could be harmful, especially because of the risk of pancreatitis. Elevation of TG is mainly due to metabolic disorders and diabetes, alcohol intake and overweight. Genetic factors have been clearly identified in the most severe cases. TG have been generally considered as bystanders for cardiovascular diseases (CVD). Both biological and basic research provide strong data suggesting that TG-rich lipoproteins could be involved in the pathophysiology of CVD. Recent epidemiological and genetics studies strongly corroborate the causal role of TG in CVD. This paves the way for new approaches in the management of patients both for primary and secondary prevention.

What have we learnt from the clinical outcomes trials with the cetrapibs?

PURPOSE OF REVIEW

The current review considers what we have learnt from the clinical outcome trials with the cetrapibs; the inhibitors of cholesteryl ester transfer protein that increase HDL cholesterol levels; torcetrapib, dalcetrapib, evacetrapib and anacetrapib.

RECENT FINDINGS

Although an off-target increase in blood pressure may have contributed to the failure of torcetrapib in Investigation of Lipid Level Management to Understand its Impact in Atherosclerotics Events, recent evidence shows that torcetrapib also increased atherogenic apoproteins, and this may have contributed to its failure. Evacetrapib and anacetrapib also increase atherogenic apoproteins. This may have contributed to lack of effect of evacetrapib in Assessment of Clinical Effects of Cholesteryl Ester Transfer Protein Inhibition with Evacetrapib in Patients at a High Risk for Vascular Outcomes. The success of anacetrapib in Randomized Evaluation of the Effects of Anacetrapib through Lipid Modification is more likely to have been due to lowering LDL cholesterol than to increasing HDL cholesterol. The lack of potency in increasing HDL cholesterol was initially considered as a reason for the failure of dalcetrapib in dal-OUTCOMES, but recent genomic studies suggest that dalcetrapib may be effective in subjects with a particular genotype, and this is being clinically tested.

SUMMARY

Collectively, these clinical outcome trials do not support raising HDL cholesterol by inhibiting cholesteryl ester transfer protein, as a mechanism for improving cardiovascular outcomes, in the total population of subjects with coronary artery disease.

Unravelling HDL-Looking beyond the Cholesterol Surface to the Quality Within

High-density lipoprotein (HDL) particles have experienced a turbulent decade of falling from grace with widespread demotion from the most-sought-after therapeutic target to reverse cardiovascular disease (CVD), to mere biomarker status. HDL is slowly emerging from these dark times due to the HDL flux hypothesis wherein measures of HDL cholesterol efflux capacity (CEC) are better predictors of reduced CVD risk than static HDL-cholesterol (HDL-C) levels. HDL particles are emulsions of metabolites, lipids, protein, and microRNA (miR) built on the backbone of Apolipoprotein A1 (ApoA1) that are growing in their complexity due to the higher sensitivity of the respective “omic” technologies. Our understanding of particle composition has increased dramatically within this era and has exposed how our understanding of these particles to date has been oversimplified. Elucidation of the HDL proteome coupled with the identification of specific miRs on HDL have highlighted the “hormonal” characteristics of HDL in that it carries and delivers messages systemically. HDL can dock to most peripheral cells via its receptors, including SR-B1, ABCA1, and ABCG1, which may be a critical step for facilitating HDL-to-cell communication. The composition of HDL particles is, in turn, altered in numerous disease states including diabetes, auto-immune disease, and CVD. The consequence of changes in composition, however, on subsequent biological activities of HDL is currently poorly understood and this is an important avenue for the field to explore in the future. Improving HDL particle quality as opposed to HDL quantity may, in turn, prove a more beneficial investment to reduce CVD risk.

CETP-Inhibition and HDL-Cholesterol: A Story of CV Risk or CV Benefit, or Both

Inhibitors of cholesteryl ester transfer protein (CETP) were developed due to their ability to raise HDL-C levels. Preclinical studies demonstrated favorable effects on atherosclerotic plaque with CETP inhibitory approaches in animal models. While these agents raise HDL-C and lower LDL-C, most have not proven to reduce cardiovascular event rates in large outcome trials. The state of opinion after all of these clinical trials is reviewed.

Acute coronary syndrome remodels the antiplatelet aggregation properties of HDL particle subclasses

Essentials HDL subclasses were studied in acute coronary syndrome (ACS). HDL2 from ACS patients have better antiplatelet potency than HDL from non ACS subjects. ACS remodels the antiplatelet properties of HDL subclasses. Oxidized polyunsaturated fatty acids content of HDL is modified by ACS.

SUMMARY

Background Although HDLs have antithrombotic effects by reducing platelet activation, the relationship between HDL levels and the risk of acute coronary syndrome (ACS) is unclear, as HDL particles are heterogeneous in composition and biological properties. Objective To characterize the effects of HDL2 and HDL3 subclasses from ACS patients and non-coronary artery disease (CAD) subjects on platelet activation. Methods We measured platelet aggregation and ex vivo thrombus formation, analyzed signaling pathways by flow cytometry, and performed a targeted lipidomics analysis on HDL subclasses. Results Analysis of human platelet aggregation in suspension, adhesion on von Willebrand factor and thrombus formation on collagen under arterial shear demonstrated that HDL2 from ACS patients had higher antiplatelet potency than HDL3 from ACS patients and HDL from non-CAD subjects. HDL binding to scavenger receptor class B type I was essential for this effect. A lipidomics analysis revealed that HDL2 from ACS patients had more oxidized polyunsaturated fatty acids (PUFAs). An inverse correlation between the concentrations of 9-hydroxyoctadecadienoic acid (9-HODE), 13-hydroxyoctadecadienoic acid (13-HODE), the eicosapentaenoic acid metabolite 18-hydroxyeicosapentaenoic acid (18-HEPE) and hydroxyeicosatetraenoic acid isomers in HDL2 and platelet aggregation was observed. This relationship was further demonstrated by the direct inhibitory effects of 18-HEPE, 9-HODE, 13-HODE, 17-hydroxydocosahexaenoic acid and 14-hydroxydocosahexaenoic acid on collagen-related peptide-induced platelet aggregation, indicating that oxidized PUFAs contribute to the antithrombotic effect of ACS HDL2. Conclusions Our data shed new light on the antiplatelet effects of HDL subclasses, and suggest physiological adaptation through the modulation of HDL properties in ACS patients that may limit their platelet-dependent thrombotic risk.

Pharmacogenomics of blood lipid regulation

Blood lipids are important modifiable risk factors for coronary heart disease and various drugs have been developed to target lipid fractions. Considerable efforts have been made to identify genetic variants that modulate responses to drugs in the hope of optimizing their use. Pharmacogenomics and new biotechnologies now allow for meaningful integration of human genetic findings and therapeutic development for increased efficiency and precision of lipid-lowering drugs. Polygenic predictors of disease risk are also changing how patient populations can be stratified, enabling targeted therapeutic interventions to patients more likely to derive the highest benefit, marking a shift from single variant to genomic approaches in pharmacogenomics.

No evidence for association of MTHFR 677C>T and 1298A>C variants with placental DNA methylation

Background

5,10-Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in one-carbon metabolism that ensures the availability of methyl groups for methylation reactions. Two single-nucleotide polymorphisms (SNPs) in the MTHFR gene, 677C>T and 1298A>C, result in a thermolabile enzyme with reduced function. These variants, in both the maternal and/or fetal genes, have been associated with pregnancy complications including miscarriage, neural tube defects (NTDs), and preeclampsia (PE), perhaps due to altered capacity for DNA methylation (DNAm). In this study, we assessed the association between MTHFR 677TT and 1298CC genotypes and risk of NTDs, PE, or normotensive intrauterine growth restriction (nIUGR). Additionally, we assessed whether these high-risk genotypes are associated with altered DNAm in the placenta.

Results

In 303 placentas screened for this study, we observed no significant association between the occurrence of NTDs (N = 55), PE (early-onset: N = 28, late-onset: N = 20), or nIUGR (N = 21) and placental (fetal) MTHFR 677TT or 1298CC genotypes compared to healthy pregnancies (N = 179), though a trend of increased 677TT genotype in PE/IUGR together was observed (OR 2.53, p = 0.048). DNAm was profiled in 10 high-risk 677 (677TT + 1298AA), 10 high-risk 1298 (677CC + 1298CC), and 10 reference (677CC + 1298AA) genotype placentas. Linear modeling identified no significantly differentially methylated sites between high-risk 677 or 1298 and reference placentas at a false discovery rate < 0.05 and Δβ ≥ 0.05 using the Illumina Infinium HumanMethylation450 BeadChip. Using a differentially methylated region analysis or separating cytosine-guanine dinucleotides (CpGs) by CpG density to reduce multiple comparisons also did not identify differential methylation. Additionally, there was no consistent evidence for altered methylation of repetitive DNA between high-risk and reference placentas.

Conclusions

We conclude that large-scale, genome-wide disruption in DNAm does not occur in placentas with the high-risk MTHFR 677TT or 1298CC genotypes. Furthermore, there was no evidence for an association of the 1298CC genotype and only a tendency to higher 677TT in pregnancy complications of PE/IUGR. This may be due to small sample sizes or folate repletion in our Canadian population attenuating effects of the high-risk MTHFR variants. However, given our results and the conflicting results in the literature, investigations into alternative mechanisms that may explain the link between MTHFR variants and pregnancy complications, or in populations at risk of folate deficiencies, are warranted.

Electronic supplementary material

The online version of this article (10.1186/s13148-018-0468-1) contains supplementary material, which is available to authorized users.

Why Drugs Fail in Late Stages of Development: Case Study Analyses from the Last Decade and Recommendations

New drug development is both resource and time intensive, where later clinical stages result in significant costs. We analyze recent late-stage failures to identify drugs where failures result from inadequate scientific advances as well as drugs where we believe pitfalls could have been avoided. These can be broadly classified into two categories: 1) where science is mature and the failures can be avoided through rigorous and prospectively determined decision-making criteria, scientific curiosity, and discipline to follow up on emerging findings; and 2) where problems encountered in Phase 3 failures cannot be explained at this time, as the science is not sufficiently advanced and companies/investigators need to recognize the possibility of deficiency of our knowledge. Through these case studies, key themes critical for successful drug development emerge-understanding the therapeutic pathway including receptor and signaling biology, pharmacological responses related to safety and efficacy, pharmacokinetics of the drug and exposure at target site, optimum dose, and dosing regimen; and identification of patient sub-populations likely to respond and will have a favorable benefit-risk profile, design of clinical trials, and a quantitative framework that can guide data-driven decision making. It is essential that the right studies are conducted early in the development process to answer the key questions, with the emphasis on learning in the early stages of development, whereas Phase 3 should be reserved for confirming the safety and efficacy. Utilization of innovative technology in identifying patients based on molecular signature of their disease, rapid assessment of pharmacological response, mechanistic modeling of emerging data, seamless operational processes to reduce start-up and wind-down time for clinical trials through use of electronic health records and data mining, and development of novel and objective clinical efficacy endpoints are some concepts for improving the success rate.

A critical appraisal of pharmacogenetic inference

In essence, pharmacogenetic research is aimed at discovering variants of importance to gene-treatment interaction. However, epidemiological studies are rarely set up with this goal in mind. It is therefore of great importance that researchers clearly communicate which assumptions they have had to make, and which inherent limitations apply to the interpretation of their results. This review discusses considerations of, and the underlying assumptions for, utilizing different response phenotypes and study designs popular in pharmacogenetic research to infer gene-treatment interaction effects, with a special focus on those dealing with of clinical effects of drug treatment.

Dyslipidemia and Risk of Cardiovascular Events in Patients With Atrial Fibrillation Treated With Oral Anticoagulation Therapy: Insights From the ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation) Trial

BACKGROUND

Dyslipidemia is a major risk factor for cardiovascular events. The prognostic importance of lipoproteins in patients with atrial fibrillation is not well understood. We aimed to explore the association between apolipoprotein A1 (ApoA1) and B (ApoB) and cardiovascular events in patients with atrial fibrillation receiving oral anticoagulation.

METHODS AND RESULTS

Using data from the ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation) trial, ApoA1 and ApoB plasma levels were measured at baseline in 14 884 atrial fibrillation patients. Median length of follow-up was 1.9 years. Relationships between continuous levels of ApoA1 and ApoB and clinical outcomes were evaluated using Cox models adjusted for cardiovascular risk factors, medication including statins, and cardiovascular biomarkers. A composite ischemic outcome (ischemic stroke, systemic embolism, myocardial infarction, and cardiovascular death) was used as the primary end point. Median (25th, 75th) ApoA1 and ApoB levels were 1.10 (0.93, 1.30) and 0.70 g/L (0.55, 0.85), respectively. In adjusted analyses, higher levels of ApoA1 were independently associated with a lower risk of the composite ischemic outcome (hazard ratio, 0.81; P<0.0001). Similar results were observed for the individual components of the composite outcome. ApoB was not significantly associated with the composite ischemic outcome (P=0.8240). Neither apolipoprotein was significantly associated with major bleeding. There was no interaction between lipoproteins and randomized treatment for the primary outcome (both P values ≥0.2448).

CONCLUSIONS

In patients with atrial fibrillation on oral anticoagulation, higher levels of ApoA1 were independently associated with lower risk of ischemic cardiovascular outcomes. Investigating therapies targeting dyslipidemia may thus be useful to improve cardiovascular outcomes in patients with atrial fibrillation.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00412984.

Elevated Adenylyl Cyclase 9 Expression Is a Potential Prognostic Biomarker for Patients with Colon Cancer

Background

Adenylyl cyclase 9 (ADCY9) is an enzyme that modulates signal transduction by producing the second messenger, cyclic adenosine monophosphate (cAMP). The aim of the present study was to investigate the association of ADCY9 expression with clinicopathological features and disease-free survival of colon cancer patients.

Material/Methods

Immunohistochemistry staining with ADCY9 antibody was performed on a tissue microarray. Immunoreactivity scores (IRS) were recorded and applied for association analysis. ADCY9 mRNA expression and clinicopathological information were also extracted from the TCGA colon cancer dataset and analyzed using univariate and multivariate Cox proportional hazards models.

Results

ADCY9 IRS was significantly higher (P=0.002) in tumor tissues (6.40±1.26, n=200) than in adjacent normal samples (4.13±0.83, n=8). The IRS and mRNA expression of ADCY9 were correlated to colon cancer TNM staging. Longer disease-free survival was observed in patients with lower ADCY9 expression (P=0.001). In the multivariate models, ADCY9 expression level (hazard ratio [HR] 5.495, 95% confidence interval [CI] 1.753–17.227, P=0.003), and distant metastasis (HR 4.329, 95% CI 1.374–13.636, P=0.012) were still associated with disease-free survival.

Conclusions

High ADCY9 expression is a poor prognostic factor for disease-free survival in colon cancer.

Present therapeutic role of cholesteryl ester transfer protein inhibitors

Therapeutic interventions aimed at increasing high-density lipoprotein (HDL) levels in order to reduce the residual cardiovascular (CV) risk of optimally drug treated patients have not provided convincing results, so far. Transfer of cholesterol from extrahepatic tissues to the liver appears to be the major atheroprotective function of HDL, and an elevation of HDL levels could represent an effective strategy. Inhibition of the cholesteryl ester transfer protein (CETP), raising HDL-cholesterol (HDL-C) and apolipoprotein A-I (apoA-I) levels, reduces low-density lipoprotein-cholesterol (LDL-C) and apoB levels, thus offering a promising approach. Despite the beneficial influence on cholesterol metabolism, off-target effects and lack of reduction in CV events and mortality (with torcetrapib, dalcetrapib and evacetrapib) highlighted the complex mechanism of CETP inhibition. After the failure of the above mentioned inhibitors in phase III clinical development, possibly due to the short duration of the trials masking benefit, the secondary prevention REVEAL trial has recently shown that the inhibitor anacetrapib significantly raised HDL-C (+104%), reduced LDL-C (-18%), with a protective effect on major coronary events (RR, 0.91; 95%CI, 0.85-0.97; p = 0.004). Whether LDL-C lowering fully accounts for the CV benefit or if HDL-C-rise is a crucial factor still needs to be determined, although the reduction of non-HDL (-18%) and Lp(a) (-25%), should be also taken into account. In spite of the positive results of the REVEAL Study, Merck decided not to proceed in asking regulatory approval for anacetrapib. Dalcetrapib (Dal-GenE study) and CKD-519 remain the two molecules within this area still in clinical development.

Anacetrapib as a potential cardioprotective strategy

Cholesteryl ester transfer protein (CETP) facilitates movement of esterified cholesterol between high-density lipoproteins (HDLs) and apolipoprotein B-containing lipoproteins. By virtue of their ability to raise HDL cholesterol and lower low-density lipoprotein cholesterol, pharmacological inhibitors of CETP have received considerable attention as potential new agents in cardiovascular prevention. While early studies of CETP inhibitors have demonstrated a lack of clinical efficacy and potential toxicity, development of the potent CETP inhibitor, anacetrapib, has moved forward, with emerging evidence suggesting a role in reducing cardiovascular events. The experience with anacetrapib and its potential for use in clinical practice are reviewed here.

Clinical Outcomes in Trials Evaluating Lipid-Lowering Drugs

While statins have formed the cornerstone of strategies for cardiovascular prevention, the residual risk related to low-density lipoprotein cholesterol (LDL-C) and other lipoprotein factors provides a landscape for development of new therapies. However, a number of lipid-modifying therapies have failed to reduce cardiovascular event rates in contemporary clinical trials of statin-treated patients. The factors considered in outcome measure selection for clinical trials of novel lipid-lowering therapies are reviewed. Evaluation of lipid-modifying drugs in clinical trials spans a spectrum from their effects on conventional circulating lipid parameters through to their impact on atherosclerotic plaque and ultimately clinical outcomes. The design of these trials has an important impact on the result and ultimate interpretation of these studies.

Design, Synthesis and Biological Evaluation of N,N-Substituted Amine Derivatives as Cholesteryl Ester Transfer Protein Inhibitors

N,N-Substituted amine derivatives were designed by utilizing a bioisosterism strategy. Consequently, twenty-two compounds were synthesized and evaluated for their inhibitory activity against CETP. Structure-activity relationship (SAR) studies indicate that hydrophilic groups at the 2-position of the tetrazole and 3,5-bistrifluoromethyl groups on the benzene ring provide important contributions to the potency. Among these compounds, compound 17 exhibited excellent CETP inhibitory activity (IC₅₀ = 0.38 ± 0.08 μM) in vitro. Furthermore, compound 17 was selected for an in vitro metabolic stability study.

Pharmacogenetics of Lipid-Lowering Agents: an Update Review on Genotype-Dependent Effects of HDL-Targetingand Statin Therapies

PURPOSE OF REVIEW

High-density lipoproteins (HDL) are involved in reverse cholesterol transport. Results from randomized trials of HDL-targeting therapies, including cholesteryl ester transfer protein (CETP) inhibitors, have shown a lack of benefit in unsegmented populations. These observations could be explained by inter-individual variability of clinical responses to such agents depending on the patients' genotypes. In parallel, although lowering of LDL cholesterol (LDL-c) with statin therapy reduces the risk of vascular events in a wide range of individuals, inter-individual variability exists with regard to LDL-c-lowering response as well as efficacy in reducing major cardiovascular events.

RECENT FINDINGS

Pharmacogenomic analyses were performed in the dal-OUTCOMES and dal-PLAQUE-2 studies. Beneficial and concordant results were observed in patients with the favorable genotype when treated with the CETP inhibitor dalcetrapib. Similarly, previous studies revealed genetic variants associated with differential LDL-c response to statin therapy. In this review, we discuss the pharmacogenetic determinants of HDL-targeting and statin therapy responses in light of the latest available published data, and their potential therapeutic applications.

Recent developments and future directions for the use of pharmacogenomics in cardiovascular disease treatments

INTRODUCTION

Cardiovascular disease is still the leading cause of death worldwide. There are many environmental and genetic factors that play a role in the development of cardiovascular disease. The treatment of cardiovascular disease is beginning to move in the direction of personalized medicine by using biomarkers from the patient's genome to design more effective treatment plans. Pharmacogenomics have already uncovered many links between genetic variation and response of many different drugs. Areas covered: This article will focus on the main polymorphisms that impact the risk of adverse effects and response efficacy of statins, clopidogrel, aspirin, β-blockers, warfarin dalcetrapib and vitamin E. The genes discussed include SLCO1B1, ABCB1, CYP3A4, CYP3A5, CYP2C19, PTGS1, PTGS2, ADRB1, ADCY9, CYP2C19, PON1, CES1, PEAR1, GPIIIa, CYP2D6, CKORC1, CYP2C9 and Hp. Expert opinion: Although there are some convincing results that have already been incorporated in the labelling treatment guidelines, most gene-drug relationships have been inconsistent. A better understanding of the relationships between genetic factors and drug response will provide more opportunities for personalized diagnosis and treatment of cardiovascular disease.

Mendelian randomisation in cardiovascular research: an introduction for clinicians

Understanding the causal role of biomarkers in cardiovascular and other diseases is crucial in order to find effective approaches (including pharmacological therapies) for disease treatment and prevention. Classical observational studies provide naïve estimates of the likely role of biomarkers in disease development; however, such studies are prone to bias. This has direct relevance for drug development as if drug targets track to non-causal biomarkers, this can lead to expensive failure of these drugs in phase III randomised controlled trials. In an effort to provide a more reliable indication of the likely causal role of a biomarker in the development of disease, Mendelian randomisation studies are increasingly used, and this is facilitated by the availability of large-scale genetic data. We conducted a narrative review in order to provide a description of the utility of Mendelian randomisation for clinicians engaged in cardiovascular research. We describe the rationale and provide a basic description of the methods and potential limitations of Mendelian randomisation. We give examples from the literature where Mendelian randomisation has provided pivotal information for drug discovery including predicting efficacy, informing on target-mediated adverse effects and providing potential new evidence for drug repurposing. The variety of the examples presented illustrates the importance of Mendelian randomisation in order to prioritise drug targets for cardiovascular research.

Dalcetrapib and anacetrapib differently impact HDL structure and function in rabbits and monkeys

Inhibition of cholesteryl ester transfer protein (CETP) increases HDL cholesterol (HDL-C) levels. However, the circulating CETP level varies and the impact of its inhibition in species with high CETP levels on HDL structure and function remains poorly characterized. This study investigated the effects of dalcetrapib and anacetrapib, the two CETP inhibitors (CETPis) currently being tested in large clinical outcome trials, on HDL particle subclass distribution and cholesterol efflux capacity of serum in rabbits and monkeys. New Zealand White rabbits and vervet monkeys received dalcetrapib and anacetrapib. In rabbits, CETPis increased HDL-C, raised small and large α-migrating HDL, and increased ABCA1-induced cholesterol efflux. In vervet monkeys, although anacetrapib produced similar results, dalcetrapib caused opposite effects because the LDL-C level was increased by 42% and HDL-C decreased by 48% (P < 0.01). The levels of α- and preβ-HDL were reduced by 16% (P < 0.001) and 69% (P < 0.01), resulting in a decrease of the serum cholesterol efflux capacity. CETPis modulate the plasma levels of mature and small HDL in vivo and consequently the cholesterol efflux capacity. The opposite effects of dalcetrapib in different species indicate that its impact on HDL metabolism could vary greatly according to the metabolic environment.

International Union of Basic and Clinical Pharmacology. CI. Structures and Small Molecule Modulators of Mammalian Adenylyl Cyclases

Adenylyl cyclases (ACs) generate the second messenger cAMP from ATP. Mammalian cells express nine transmembrane AC (mAC) isoforms (AC1-9) and a soluble AC (sAC, also referred to as AC10). This review will largely focus on mACs. mACs are activated by the G-protein Gαs and regulated by multiple mechanisms. mACs are differentially expressed in tissues and regulate numerous and diverse cell functions. mACs localize in distinct membrane compartments and form signaling complexes. sAC is activated by bicarbonate with physiologic roles first described in testis. Crystal structures of the catalytic core of a hybrid mAC and sAC are available. These structures provide detailed insights into the catalytic mechanism and constitute the basis for the development of isoform-selective activators and inhibitors. Although potent competitive and noncompetitive mAC inhibitors are available, it is challenging to obtain compounds with high isoform selectivity due to the conservation of the catalytic core. Accordingly, caution must be exerted with the interpretation of intact-cell studies. The development of isoform-selective activators, the plant diterpene forskolin being the starting compound, has been equally challenging. There is no known endogenous ligand for the forskolin binding site. Recently, development of selective sAC inhibitors was reported. An emerging field is the association of AC gene polymorphisms with human diseases. For example, mutations in the AC5 gene (ADCY5) cause hyperkinetic extrapyramidal motor disorders. Overall, in contrast to the guanylyl cyclase field, our understanding of the (patho)physiology of AC isoforms and the development of clinically useful drugs targeting ACs is still in its infancy.

Evidence-based goals in LDL-C reduction

The evidence from trials of statin therapy suggests that benefits in cardiovascular disease (CVD) event reduction are proportional to the magnitude of low-density lipoprotein cholesterol (LDL-C) lowering. The lack of a threshold at which LDL-C lowering is not beneficial, in terms of CVD prevention observed in these trials, is supported by epidemiological and genetic studies reporting the cardio-protective effects of lifelong low exposure to atherogenic cholesterol in a graded fashion. Providing that intensive LDL-C lowering is safe, these observations suggest that many individuals even at current LDL-C treatment targets could benefit. Here, we review recent safety and efficacy data from trials of adjunctive therapy, with LDL-C lowering beyond that achieved by statin therapy, and their potential implications for current guideline targets. Finally, the application of current guidance in the context of pre-treatment LDL-C concentration and deployment of statin therapy is also discussed. The number of patients requiring treatment to prevent a CVD event with statin treatment has been shown to differ markedly according to the pre-treatment LDL-C concentration even when absolute CVD risk is similar. It produces more likelihood of benefit when absolute LDL-C reduction is greater which is largely dependent on pre-treatment LDL-C concentration. This also has to be taken in consideration when deploying new agents like proprotein convertase subtilisin/kexin type 9 monoclonal antibodies. Patients with highest LDL-C concentration despite maximum statin and ezetimibe therapy will attain most absolute LDL-C reduction when treated with proprotein convertase subtilisin/kexin type 9 monoclonal antibodies, hence benefit most in term of CVD risk reduction.

CETP

High-density lipoproteins are involved in reverse cholesterol transport and possess anti-inflammatory and antioxidative properties. Paradoxically, CETP (cholesteryl ester transfer protein) inhibitors have been shown to increase inflammation as revealed by a raised plasma level of high-sensitivity C-reactive protein. CETP inhibitors did not improve clinical outcomes in large-scale clinical trials of unselected patients with coronary disease. Dalcetrapib is a CETP modulator for which effects on cardiovascular outcomes were demonstrated in the dal-OUTCOMES trial to be influenced by correlated polymorphisms in the ADCY9 (adenylate cyclase type 9) gene ( P =2.4×10 −8 for rs1967309). Patients with the AA genotype at rs1967309 had a relative reduction of 39% in the risk of presenting a cardiovascular event when treated with dalcetrapib compared with placebo (95% confidence interval, 0.41–0.92). In contrast, patients with the GG genotype had a 27% increase in risk, whereas heterozygotes (AG) presented a neutral result. Supporting evidence from the dal-PLAQUE-2 study using carotid ultrasonography revealed that the polymorphisms tested in the ADCY9 linkage disequilibrium block were associated with disease regression for patients with the protective genotype, progression for the harmful genotype, and no effect in heterozygotes ( P ≤0.05 and ≤0.01 for 10 and 3 polymorphisms, respectively) when comparing dalcetrapib to placebo. Strikingly concordant and significant genotype-dependent effects of dalcetrapib were also obtained for changes in high-sensitivity C-reactive protein and cholesterol efflux capacity. The Dal-GenE randomized trial is currently being conducted in patients with a recent acute coronary syndrome bearing the AA genotype at rs1967309 in the ADCY9 gene to confirm the effects of dalcetrapib on hard cardiovascular outcomes.

Personalized Management of Cardiovascular Disorders

Personalized management of cardiovascular disorders (CVD), also referred to as personalized or precision cardiology in accordance with general principles of personalized medicine, is selection of the best treatment for an individual patient. It involves the integration of various "omics" technologies such as genomics and proteomics as well as other new technologies such as nanobiotechnology. Molecular diagnostics and biomarkers are important for linking diagnosis with therapy and monitoring therapy. Because CVD involve perturbations of large complex biological networks, a systems biology approach to CVD risk stratification may be used for improving risk-estimating algorithms, and modeling of personalized benefit of treatment may be helpful for guiding the choice of intervention. Bioinformatics tools are helpful in analyzing and integrating large amounts of data from various sources. Personalized therapy is considered during drug development, including methods of targeted drug delivery and clinical trials. Individualized recommendations consider multiple factors - genetic as well as epigenetic - for patients' risk of heart disease. Examples of personalized treatment are those of chronic myocardial ischemia, heart failure, and hypertension. Similar approaches can be used for the management of atrial fibrillation and hypercholesterolemia, as well as the use of anticoagulants. Personalized management includes pharmacotherapy, surgery, lifestyle modifications, and combinations thereof. Further progress in understanding the pathomechanism of complex cardiovascular diseases and identification of causative factors at the individual patient level will provide opportunities for the development of personalized cardiology. Application of principles of personalized medicine will improve the care of the patients with CVD.

Inflammation and beyond: new directions and emerging drugs for treating atherosclerosis

INTRODUCTION

Cardiovascular (CV) atherosclerotic disease remains the leading cause of morbidity and mortality worldwide, despite the advances in contemporary therapies. Inflammation is an important process in atherosclerosis, leading to plaque rupture and acute coronary syndrome. Although statin therapy has substantially reduced CV events in primary and secondary prevention, many treated patients will have recurrent adverse CV events despite the standard of care. Thus, drug development aiming to target inflammatory pathways seems a promising avenue for novel therapies in atherosclerosis. Areas covered: Statins have been extensively studied and are the most effective lipid-lowering drugs available for CV prevention. Novel anti-inflammatory drugs are being tested in Phase II and III trials, targeting pathways like interleukin-1, leukotrienes, TNF-α, P-selectin, CCL2-CCR2 and MAP Kinase. Expert opinion: Novel anti-inflammatory therapies seem promising additions to address the residual CV risk present despite the current standard of care, but large clinical trials have not yet shown beneficial effects on clinical events. PCSK9 inhibitors have been shown to substantially reduce LDL-C, however their long-term safety and effects on CV risk are currently being investigated. Pharmacogenomics holds great potential in future lipid trials, enabling the identification of patients who will respond with greater benefits and smaller risk to therapies and to decrease failure rates in drug development, as genotype-dependent effects of the CETP inhibitor dalcetrapib were shown in the dal-OUTCOMES and dal-PLAQUE-2 trials.