Long-term safety and efficacy of anacetrapib in patients with atherosclerotic vascular disease

AIMS

REVEAL was the first randomized controlled trial to demonstrate that adding cholesteryl ester transfer protein inhibitor therapy to intensive statin therapy reduced the risk of major coronary events. We now report results from extended follow-up beyond the scheduled study treatment period.

METHODS AND RESULTS

A total of 30 449 adults with prior atherosclerotic vascular disease were randomly allocated to anacetrapib 100 mg daily or matching placebo, in addition to open-label atorvastatin therapy. After stopping the randomly allocated treatment, 26 129 survivors entered a post-trial follow-up period, blind to their original treatment allocation. The primary outcome was first post-randomization major coronary event (i.e. coronary death, myocardial infarction, or coronary revascularization) during the in-trial and post-trial treatment periods, with analysis by intention-to-treat. Allocation to anacetrapib conferred a 9% [95% confidence interval (CI) 3-15%; P = 0.004] proportional reduction in the incidence of major coronary events during the study treatment period (median 4.1 years). During extended follow-up (median 2.2 years), there was a further 20% (95% CI 10-29%; P < 0.001) reduction. Overall, there was a 12% (95% CI 7-17%, P < 0.001) proportional reduction in major coronary events during the overall follow-up period (median 6.3 years), corresponding to a 1.8% (95% CI 1.0-2.6%) absolute reduction. There were no significant effects on non-vascular mortality, site-specific cancer, or other serious adverse events. Morbidity follow-up was obtained for 25 784 (99%) participants.

CONCLUSION

The beneficial effects of anacetrapib on major coronary events increased with longer follow-up, and no adverse effects emerged on non-vascular mortality or morbidity. These findings illustrate the importance of sufficiently long treatment and follow-up duration in randomized trials of lipid-modifying agents to assess their full benefits and potential harms.

TRIAL REGISTRATION

International Standard Randomized Controlled Trial Number (ISRCTN) 48678192; ClinicalTrials.gov No. NCT01252953; EudraCT No. 2010-023467-18.

Clinical guidelines on hyperlipidaemia: recent developments, future challenges and the need for an Australian review

Large reductions in cardiovascular disease (CVD) mortality have been achieved over the last 50 years in developed countries. The health policies that have contributed so much to this success have largely been coordinated by means of expert guidelines for the management of the classic modifiable risk factors such as blood pressure, diabetes and blood lipids. National and international guidelines for lipid management have demonstrated a high degree of consistency between numerous sets of recommendations. It has been argued that some important components of the consensus that has been established over the past decade have been challenged by the latest guidelines of the American Heart Association - American College of Cardiologists (AHA-ACC). Clinicians can be reassured that continued reliance on extensive scientific evidence has reaffirmed the importance of lipid metabolism as a modifiable risk factor for atherosclerotic cardiovascular disease. On the other hand, the recent AHA-ACC guidelines suggest changes in the strategies by which metabolic risk factors may be modified. This small number of important changes should not be sensationalised because these differences usefully reflect the need for guidelines to evolve to accommodate different contexts and changing perspectives as well as emerging issues and new information for which clinical trial evidence is incomplete. This article will consider the recent policies and responses of national and supranational organisations on topics including components of CVD risk assessment, sources of CVD risk information and re-appraisal of lipid-lowering interventions. Timely review of Australian lipid management guidelines will require consideration of these issues because they are creating a new context within which new guidelines must evolve.

Usefulness of measuring both body mass index and waist circumference for the estimation of visceral adiposity and related cardiometabolic risk profile (from the INSPIRE ME IAA study)

Despite its well-documented relation with visceral adiposity (VAT) and cardiometabolic risk (CMR), whether waist circumference (WC) should be measured in addition to body mass index (BMI) remains debated. This study tested the relevance of adding WC to BMI for the estimation of VAT and CMR. In the International Study of Prediction of Intra-abdominal Adiposity and Its Relationship with Cardiometabolic Risk/Intra-abdominal Adiposity, 297 physicians recruited 4,504 patients (29 countries). Both BMI and WC were measured, whereas VAT and liver fat were assessed by computed tomography. A composite CMR score was calculated. From the 4,109 patients included in the present analyses (20 ≤ BMI < 40 kg/m(2), 47% women), about 30% displayed discordant values for WC and BMI quintiles, despite a strong correlation between the 2 anthropometric variables (r = 0.87 and r = 0.84 for men and women, respectively, p <0.001). Within each single BMI unit, VAT and WC showed substantial variability between subjects (mean difference between 90th and 10th percentiles: 175 cm(2)/16 cm and 137 cm(2)/18 cm for VAT/WC in men and women, respectively). Within each BMI category, increasing gender-specific WC tertiles were associated with significantly higher VAT, liver fat, and with a more adverse CMR profile. In conclusion, this large international cardiometabolic study highlights the frequent discordance between BMI and WC, driven by the substantial variability in VAT for a given BMI. Within each BMI category, WC was cross-sectionally associated with VAT, liver fat, and CMR factors. Thus, WC allows a further refinement of the CMR related to any given BMI.

A genome-wide association study reveals variants in ARL15 that influence adiponectin levels

The adipocyte-derived protein adiponectin is highly heritable and inversely associated with risk of type 2 diabetes mellitus (T2D) and coronary heart disease (CHD). We meta-analyzed 3 genome-wide association studies for circulating adiponectin levels (n = 8,531) and sought validation of the lead single nucleotide polymorphisms (SNPs) in 5 additional cohorts (n = 6,202). Five SNPs were genome-wide significant in their relationship with adiponectin (P< or =5x10(-8)). We then tested whether these 5 SNPs were associated with risk of T2D and CHD using a Bonferroni-corrected threshold of P< or =0.011 to declare statistical significance for these disease associations. SNPs at the adiponectin-encoding ADIPOQ locus demonstrated the strongest associations with adiponectin levels (P-combined = 9.2x10(-19) for lead SNP, rs266717, n = 14,733). A novel variant in the ARL15 (ADP-ribosylation factor-like 15) gene was associated with lower circulating levels of adiponectin (rs4311394-G, P-combined = 2.9x10(-8), n = 14,733). This same risk allele at ARL15 was also associated with a higher risk of CHD (odds ratio [OR] = 1.12, P = 8.5x10(-6), n = 22,421) more nominally, an increased risk of T2D (OR = 1.11, P = 3.2x10(-3), n = 10,128), and several metabolic traits. Expression studies in humans indicated that ARL15 is well-expressed in skeletal muscle. These findings identify a novel protein, ARL15, which influences circulating adiponectin levels and may impact upon CHD risk.

Effects of long-term fenofibrate therapy on cardiovascular events in 9795 people with type 2 diabetes mellitus (the FIELD study): randomised controlled trial

BACKGROUND

Patients with type 2 diabetes mellitus are at increased risk of cardiovascular disease, partly owing to dyslipidaemia, which can be amenable to fibrate therapy. We designed the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study to assess the effect of fenofibrate on cardiovascular disease events in these patients.

METHODS

We did a multinational, randomised controlled trial with 9795 participants aged 50-75 years, with type 2 diabetes mellitus, and not taking statin therapy at study entry. After a placebo and a fenofibrate run-in phase, we randomly assigned patients (2131 with previous cardiovascular disease and 7664 without) with a total-cholesterol concentration of 3.0-6.5 mmol/L and a total-cholesterol/HDL-cholesterol ratio of 4.0 or more or plasma triglyceride of 1.0-5.0 mmol/L to micronised fenofibrate 200 mg daily (n=4895) or matching placebo (n=4900). Our primary outcome was coronary events (coronary heart disease death or non-fatal myocardial infarction); the outcome for prespecified subgroup analyses was total cardiovascular events (the composite of cardiovascular death, myocardial infarction, stroke, and coronary and carotid revascularisation). Analysis was by intention to treat. The study was prospectively registered (number ISRCTN 64783481).

FINDINGS

Vital status was confirmed on all but 22 patients. Averaged over the 5 years' study duration, similar proportions in each group discontinued study medication (10% placebo vs 11% fenofibrate) and more patients allocated placebo (17%) than fenofibrate (8%; p<0.0001) commenced other lipid treatments, predominantly statins. 5.9% (n=288) of patients on placebo and 5.2% (n=256) of those on fenofibrate had a coronary event (relative reduction of 11%; hazard ratio [HR] 0.89, 95% CI 0.75-1.05; p=0.16). This finding corresponds to a significant 24% reduction in non-fatal myocardial infarction (0.76, 0.62-0.94; p=0.010) and a non-significant increase in coronary heart disease mortality (1.19, 0.90-1.57; p=0.22). Total cardiovascular disease events were significantly reduced from 13.9% to 12.5% (0.89, 0.80-0.99; p=0.035). This finding included a 21% reduction in coronary revascularisation (0.79, 0.68-0.93; p=0.003). Total mortality was 6.6% in the placebo group and 7.3% in the fenofibrate group (p=0.18). Fenofibrate was associated with less albuminuria progression (p=0.002), and less retinopathy needing laser treatment (5.2%vs 3.6%, p=0.0003). There was a slight increase in pancreatitis (0.5%vs 0.8%, p=0.031) and pulmonary embolism (0.7%vs 1.1%, p=0.022), but no other significant adverse effects.

INTERPRETATION

Fenofibrate did not significantly reduce the risk of the primary outcome of coronary events. It did reduce total cardiovascular events, mainly due to fewer non-fatal myocardial infarctions and revascularisations. The higher rate of starting statin therapy in patients allocated placebo might have masked a moderately larger treatment benefit.

Comparison of rosuvastatin with atorvastatin, simvastatin and pravastatin in achieving cholesterol goals and improving plasma lipids in hypercholesterolaemic patients with or without the metabolic syndrome in the MERCURY I trial

AIM

The metabolic syndrome (MS) increases the risk of coronary heart disease, yet few data are available on the effects of statin treatment in improving lipid measures in patients with the syndrome. This analysis compares the effects of statin therapy on plasma low-density lipoprotein cholesterol (LDL-C) goal achievement and lipid levels in hypercholesterolaemic patients with or without the MS.

METHODS

The Measuring Effective Reductions in Cholesterol Using Rosuvastatin TherapY I (MERCURY I) trial compared rosuvastatin 10 mg with atorvastatin 10 mg and 20 mg, simvastatin 20 mg and pravastatin 40 mg over 8 weeks in patients with coronary or other atherosclerotic diseases or diabetes who had fasting levels of LDL-C of >or=2.99 mmol/l and triglycerides of <4.52 mmol/l. Modified National Cholesterol Education Program Adult Treatment Panel III (ATP III) criteria for the MS were met by 1342 (43%) of 3140 patients.

RESULTS

LDL-C goal achievement rates and reductions in LDL-C, total cholesterol and non-high-density lipoprotein cholesterol (HDL-C) were similar in patients with and without the MS within statin treatment groups; triglycerides were reduced more and HDL-C tended to be increased more in patients with the MS, as expected. Treatment with rosuvastatin 10 mg was more effective in allowing patients with and without the MS to reach European and ATP III LDL-C goals, compared to atorvastatin 10 mg, simvastatin 20 mg and pravastatin 40 mg (p < 0.0001 for all comparisons); consistently produced greater reductions in LDL-C, total cholesterol and non-HDL-C, compared to these treatments; and produced similar or greater reductions in triglycerides and increases in HDL-C, compared to the other treatments.

CONCLUSIONS

Statin therapy is effective in allowing LDL-C goal achievement and improving the lipid profile in hypercholesterolaemic high-risk patients with the MS. Rosuvastatin 10 mg presents significant advantages in goal achievement and lipid lowering over other statins at commonly used doses in patients both with and without the MS.

Treatment of dyslipidaemia in high-risk patients: too little, too late

Evidence that lowering low-density cholesterol (LDL-C) reduces coronary events and mortality is now overwhelming and is reflected in treatment guidelines from around the world. The Joint European Guidelines recommend an LDL-C goal of <3.0 mmol/l in high-risk subjects. The National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP)-III guidelines suggest an even more aggressive approach in high-risk individuals, with a recommended LDL-C goal of <2.6 mmol/l. Large numbers of high-risk patients are still not achieving the more conservative goals recommended in the Joint European Guidelines, let alone the more aggressive LDL-C target recommended in the new NCEPATP-III guidelines. The recognition in the NCEP ATP-III guidelines that a high-density lipoprotein cholesterol (HDL-C) level <1.0 mmol/l represents an important risk factor highlights the emergence of HDL-C as a key player in the genesis of coronary heart disease (CHD) and as a potential target for therapy. This may be especially important in people with insulin resistance with or without type 2 diabetes. There is evidence from the Helsinki Heart Study and the more recent Veterans Affairs HDL Intervention Trial (VA-HIT), both of which used gemfibrozil as the active agent, that the observed reduction in coronary events was correlated with the magnitude of the increase in HDL-C. The challenge for future management of high-risk individuals will be not only to reduce the level of LDL-C to below 2.6 mmol/l but also to increase HDL-C to levels above 1.0 mmol/l.

Regulation of leucocyte-endothelial interactions of special relevance to atherogenesis

1. The cellular events underlying atherosclerosis include the accumulation of lipid-laden monocytes in the neointima. This process is associated with the expression of adhesion proteins and chemokines by the endothelium, in a manner similar to that seen after the administration of pro-inflammatory cytokines to endothelial cells. 2. The processes that limit endothelial responses to proinflammatory cytokines are, therefore, the subject of this paper. Evidence is presented that the cytokine TGF-beta exerts a tonic inhibitory influence on endothelial responses. Furthermore, the smooth muscle cells adjacent to endothelial cells have a similar effect to exogenous TGF-beta and this suggests that these two cells form a functional interactive unit. Finally, the atheroprotective lipid fraction, high-density lipoproteins (HDL), also inhibits endothelial activation. The mechanism of effect of HDL that appears separate from its traditional role in cholesterol transport may yield novel insights into atheroprotection.

A comparative study of the efficacy of simvastatin and gemfibrozil in combined hyperlipoproteinemia: prediction of response by baseline lipids, apo E genotype, lipoprotein(a) and insulin

Combined hyperlipoproteinemia (CHL) can be difficult to treat because of the heterogeneous nature of the lipoprotein abnormalities. We compared the relative efficacies of simvastatin and gemfibrozil and sought predictors of responsiveness in terms of the baseline lipids and other potential metabolic determinants (plasma insulin, Lp(a) and apo E genotype). Sixty-six subjects entered a cross-over, randomized trial involving 12 weeks on each drug. Efficacy was assessed after 6 and 12 weeks on each treatment. Simvastatin lowered total cholesterol 24%, triglycerides 12%, LDL cholesterol 33%, raised HDL cholesterol 13% and substantially reduced the cholesterol:triglyceride ratio in VLDL and IDL. Gemfibrozil lowered total cholesterol 5%, triglycerides 44%, raised HDL 26% and reduced VLDL and IDL lipids more than simvastatin did. LDL size increased with both treatments and HDL size increased with simvastatin. Responsiveness (25% fall in cholesterol or 40% fall in triglycerides) was shown by 31/61 subjects when taking simvastatin (cholesterol-lowering) and by 44/60 taking gemfibrozil (triglyceride-lowering). Responsiveness was greatest in those with apo E2 genotype with both drugs (P < 0.05). Unexpectedly, responders to simvastatin tended to have lower baseline total cholesterol but higher triglyceride levels than those whose cholesterol or triglyceride was lowered by gemfibrozil. Nevertheless, more hypercholesterolemic subjects responded to simvastatin and more hypertriglyceridemic subjects to gemfibrozil. Lp(a) (P = 0.04) and plasma insulin concentrations (P = 0.03) were negative predictors of percentage triglyceride-lowering with gemfibrozil. The difference between the two drugs in triglyceride-lowering lessened with rising insulin and falling HDL cholesterol. Thus, the responsiveness to the two major classes of lipid lowering drugs can be partly predicted from baseline lipids and related metabolic parameters.

Cholesteryl ester transfer protein: its role in plasma lipid transport

1. The cholesteryl ester transfer protein (CETP) is a hydrophobic glycoprotein which acts in plasma to redistribute cholesteryl esters and triglyceride between plasma lipoproteins. 2. CETP also plays an important role in determining the composition and particle size distribution of high density lipoproteins (HDL). 3. Activity of CETP may be regulated in four ways: By factors which influence the concentration of CETP in plasma; by the activity of CETP inhibitor proteins; by variations in the concentrations and compositions of donor and acceptor lipoproteins and by factors which influence the interaction of CETP with plasma lipoproteins. 4. The mechanism of action of CETP is uncertain. Two models have been proposed: (i) a shuttle model in which CETP physically transports lipids between lipoprotein particles and (ii) a ternary complex model in which CETP forms a bridge between two lipoprotein particles, enabling them to exchange lipids. 5. Evidence is accumulating that CETP may be a pro-atherogenic factor.

Cholesterol and cardiovascular disease: basic science

Cholesterol is a normal constituent of blood plasma and of cell membranes in every tissue of the body. It is transported in plasma as a component of lipoproteins. Increased concentrations of specific lipoprotein fractions, namely low density lipoproteins (LDL) and intermediate density lipoproteins (IDL), have been implicated both in vitro and in vivo as causes of atherosclerosis. The mechanism by which these lipoproteins initiate atherosclerosis is unknown, although there is growing evidence that it involves interactions between lipoproteins and cells within the artery wall, setting in train complex, reactions which lead ultimately to the fully developed lesions.

Application of reversed-phase high-performance liquid chromatography to the separation of apolipoproteins A-IV, A-I and E from rat high-density lipoprotein

Apolipoproteins A-IV, A-I and E from rat high-density lipoprotein (HDL) were successfully purified by reversed-phase high-performance liquid chromatography (RP-HPLC), using a method which we have previously developed for the separation of apolipoproteins A-IV, A-I and E from human lymph chylomicrons [T. Tetaz, E. Kecorius, B. Grego and N. Fidge, J. Chromatogr., 511 (1990) 147]. Since analytical-scale RP-HPLC indicated that the C apolipoproteins from rat HDL coeluted with both apo A-IV and apo A-I, delipidated rat HDL was first subjected to preparative-scale size-exclusion HPLC (HPSEC) on a Serva Si300 column, which effectively separated the C apolipoproteins from all but apolipoprotein E. Fractions from HPSEC which were enriched for apolipoproteins A-IV, A-I or E were directly applied to RP-HPLC on a TSK Phenyl-5PW column. This procedure yielded fractions containing apolipoproteins A-IV, A-I or E which were pure as assessed by N-terminal sequencing and silver staining of sodium dodecyl sulphate-polyacrylamide gels.

Metabolism of high density lipoproteins by the perfused rabbit liver

The role of the liver in the catabolism of high density lipoproteins (HDL) was examined in isolated perfused rabbit livers. Using 125I-labeled rabbit HDL the disappearance of labeled apolipoproteins from the perfusate was biphasic with 7% of the label removed after 20 min and a further 6% between 20 and 90 min. In contrast, with HDL labeled with [3H]cholesteryl esters 35% of label had been removed after 90 min. The effect of liver perfusion on HDL size and composition was further studied by recirculating rabbit HDL for 120 min. In control experiments HDL was incubated at 37 degrees C for 120 min with nonperfused media and with media that had been liver perfused. The added HDL was predominantly particles of 4.8-4.9-mm radius, and incubation with nonperfused and preperfused media produced no significant change in size. However, liver perfusion resulted in particles predominantly 4.2-4.3-mm radius. Hepatic perfusion also significantly reduced HDL cholesteryl ester composition as a percentage of lipoproteins mass from 13.3 +/- 2.2% in control incubations to 10.7 +/- 3.1% (p less than 0.001), and cholesteryl ester:protein mass ratio was reduced from 0.31 +/- 0.06 in control to 0.24 +/- 0.10 (p less than 0.001) after 120 min of liver perfusion. Thus interaction of rabbit HDL with rabbit liver results in smaller HDL particles significantly depleted of core cholesteryl esters.

High density lipoprotein subpopulations in chronic liver disease

Severe liver disease may be associated with a reduction in plasma concentration of high density lipoprotein and an impairment of plasma cholesterol esterification. These changes were confirmed in two patients with severe acute on chronic alcoholic liver disease. In five additional patients with biopsy-proven clinically compensated cirrhosis, there was minimal reduction in concentration of plasma cholesteryl esters; there was, however a reduction of the plasma high density lipoprotein concentration to only 48 to 66% of normal. The particle size distribution of high density lipoprotein in these five patients was determined by gradient gel electrophoresis. The high density lipoprotein2 subfraction was preserved. The high density lipoprotein3 subfraction, however, was markedly changed with a reduction in the normal particles of radius 4.3 m and an accentuation of smaller particles of radius 3.9 m; in two patients, these smaller particles were the major high density lipoprotein subpopulation. Further investigations of this finding of a distinctive distribution of high density lipoprotein subpopulations in patient with chronic liver disease may provide new insights into high density lipoprotein metabolism.

Metabolism of cholesteryl esters of very low density lipoproteins in the guinea pig

Very low density lipoproteins from guinea pig plasma, endogenously labeled with 3H in both the esterified and free cholesterol moieties, were obtained from serum collected 20 hr after the intravenous injection of 3H-cholesterol into donor animals. When these lipoproteins were injected into recipient guinea pigs, the esterified 3H-cholesterol was rapidly cleared from the plasma; 24% was in the liver in 5 min and 54% in 15 min. A smaller fraction of the esterified cholesterol appeared in other plasma lipoprotein fractions, with 3H in the low density lipoproteins reaching a peak of 9%-18% of the injected esterified 3H-cholesterol between 30 and 60 min after the injection. The results indicate that most of the esterified cholesterol in very low density lipoproteins of guinea pig plasma is removed directly by the liver and a minor fraction is transferred to low density lipoproteins. The pattern of labeling of cholesteryl esters of high density lipoproteins in these experiments suggests that their low concentration in the guinea pig is accompanied by a rapid turnover rate.

Metabolism of palmitic and linoleic acids in man: differences in turnover and conversion to glycerides

1. The metabolism of palmitic acid (a saturated fatty acid) and linoleic acid (a polyunsaturated fatty acid) was compared in seven subjects during constant infusions of the radioactive tracers.

2. The studies were repeated in some subjects after the turnover of the free fatty acids and the size of the fatty acid and glyceride pools had been altered with sucrose or polyunsaturated fat diets.

3. The fractional turnover of linoleic acid was nearly always greater than that of palmitic acid, though its total turnover rate was less.

4. A lesser proportion of the turnover of linoleate than of palmitate was incorporated into plasma triglyceride over a range of turnover rates of free fatty acids and glyceride fatty acid pools. This may be a factor in the lowering of plasma triglyceride concentrations with diets rich in polyunsaturated fatty acids.