Review of extended-release niacin/laropiprant fixed combination in the treatment of mixed dyslipidemia and primary hypercholesterolemia

Lipoprotein apheresis is an optimal therapeutic option to reduce increased Lp(a) levels

BACKGROUND

Lipoprotein(a) (Lp(a)) is a genetic risk factor for cardiovascular disease (CVD) and is associated with the induction and sustaining of atherosclerotic cardiovascular diseases (ASCVD). Since 2008 Lp(a) along with progressive CVD has been approved as an indication for regular lipoprotein apheresis (LA) in Germany. The German Lipoprotein Apheresis Registry (GLAR) has been initiated to provide statistical evidence for the assessment of extracorporeal procedures to treat dyslipidemia for both LDL-cholesterol (LDL-C) and Lp(a). The GLAR now allows prospective investigations over a 5-year period about annual incidence rates of cardiovascular events. Here Lp(a) patients (LDL-C < 100 mg/dl; Lp(a) > 60 mg/dl or >120 nmol/l) showed the same reduction of major coronary (83%) and non-coronary events (63%) as had been formerly shown in the Pro(a)LiFe study. However, Lp(a) is not only an apolipoprotein(a) (apo(a)) and LDL-C containing particle, which is covalently bound to a LDL-C core by a disulphide bridge. The composition of this particle, inter alia containing oxidized phospholipids, gives pro-atherosclerotic, pro-inflammatory, and pro-thrombotic properties, inducing atherosclerotic processes mainly in the arterial wall. However, recent investigations have shown that a reduction of inflammatory settings without LDL-C or Lp(a) reduction may reduce ASCVD events. Lipoprotein apheresis (LA) could not only reduce LDL-C and Lp(a) in parallel, but also different inflammatory and coagulation parameters. In summary lipoprotein apheresis is not only anti-atherosclerotic, but also anti-inflammatory and anti-thrombotic and therefore an ideal treatment option with respect to the shown reduction of major adverse coronary events (MACE) and major adverse non-coronary events (MANCE) by reducing Lp(a) levels.

High-density Lipoprotein and Low-density Lipoprotein Therapeutic Approaches in Acute Coronary Syndromes

BACKGROUND

Low-density lipoprotein cholesterol (LDL), and especially its oxidized form, renders the atherosclerotic plaque vulnerable to rupture in acute coronary syndromes (ACS). On the other hand, high-density lipoprotein (HDL) is considered an anti-atherogenic molecule. The more recent HDL-targeted drugs may prove to be superior to those used before. Indeed, delipidated HDL and HDL mimetics are efficient in increasing HDL levels, while the apoA-I upregulation with RVX-208 appears to offer a clinical benefit which is beyond the HDL related effects. HDL treatment however has not shown a significant improvement in the outcomes of patients with ACS so far, studies have therefore focused again on LDL. In addition to statins and ezetimibe, novel drugs such as PSCK9 inhibitors and apolipoprotein B inhibitors appear to be both effective and safe for patients with hyperlipidemia.

CONCLUSION

Data suggest these could potentially improve the cardiovascular outcomes of patient with ACS. Yet, there is still research to be done, in order to confirm whether ACS patients would benefit from LDL- or HDL-targeted therapies or a combination of both.

Cardiovascular disease risk reduction by raising HDL cholesterol--current therapies and future opportunities

Since the first discovery of an inverse correlation between high-density lipoprotein-cholesterol (HDL-C) levels and coronary heart disease in the 1950s the life cycle of HDL, its role in atherosclerosis and the therapeutic modification of HDL-C levels have been major research topics. The Framingham study and others that followed could show that HDL-C is an independent cardiovascular risk factor and that the increase of HDL-C of only 10 mg·L(-1) leads to a risk reduction of 2-3%. While statin therapy and therefore low-density lipoprotein-cholesterol (LDL-C) reduction could lower coronary heart disease considerably; cardiovascular morbidity and mortality still occur in a significant portion of subjects already receiving therapy. Therefore, new strategies and therapies are needed to further reduce the risk. Raising HDL-C was thought to achieve this goal. However, established drug therapies resulting in substantial HDL-C increase are scarce and their effect is controversial. Furthermore, it is becoming increasingly evident that HDL particle functionality is at least as important as HDL-C levels since HDL particles not only promote reverse cholesterol transport from the periphery (mainly macrophages) to the liver but also exert pleiotropic effects on inflammation, haemostasis and apoptosis. This review deals with the biology of HDL particles, the established and future therapeutic options to increase HDL-C and discusses the results and conclusions of the most important studies published in the last years. Finally, an outlook on future diagnostic tools and therapeutic opportunities regarding coronary artery disease is given.

The effect of niacin on serum phosphorus levels in dialysis patients

Hyperphosphatemia is common in patients with end-stage renal disease. Recent studies have shown that niacinamide and niacin achieve clinically significant reductions in serum phosphate in patients undergoing dialysis. The aim of the present study was to evaluate the serum phosphorus lowering effect of niacin in long-term hemodialysis patients. In this 8-week randomized, double-blind clinical trial, 37 patients were assigned to niacin or placebo with titration from 400 to 1000 mg daily. A 2-week washout preceded the switch from niacin to placebo or vice versa. The mean dose of niacin at the end of the 8-week treatment period was 750±200 mg/day. Serum phosphorus decreased from 6.66±1.40 to 5.96±0.87 mg/dL (P = 0.006) in the niacin-treated group after 8-weeks. However, the main reduction occurred at the beginning of study and seems not to be related to the phosphate-lowering effect of drug. In spite of a sharp increase in phosphorus level between w6 and w8 in patients on placebo, phosphorus values in drug-treated group showed nearly steady trend, presumably due to the inhibitory effect of niacin on phosphate absorption from gut. Niacin also increased the high density lipoprotein (HDL) cholesterol (P = 0.018). Our study suggests that niacin should be considered as adjunctive therapy for patients with hyperphosphatemia despite management with phosphate binders. The modest increase in HDL values may be another beneficial effect of this treatment.

Attenuation of niacin-induced prostaglandin D(2) generation by omega-3 fatty acids in THP-1 macrophages and Langerhans dendritic cells

Niacin, also known as nicotinic acid, is an organic compound that has several cardio-beneficial effects. However, its use is limited due to the induction of a variable flushing response in most individuals. Flushing occurs from a niacin receptor mediated generation of prostaglandins from arachidonic acid metabolism. This study examined the ability of docosahexaenoic acid, eicosapentaenoic acid, and omega-3 polyunsaturated fatty acids (PUFAs), to attenuate niacin-induced prostaglandins in THP-1 macrophages. Niacin induced both PGD₂ and PGE₂ generation in a dose-dependent manner. Niacin also caused an increase in cytosolic calcium and activation of cytosolic phospholipase A₂. The increase in PGD₂ and PGE₂ was reduced by both docosahexaenoic acid and eicosapentaenoic acid, but not by oleic acid. Omega-3 PUFAs efficiently incorporated into cellular phospholipids at the expense of arachidonic acid, whereas oleic acid incorporated to a higher extent but had no effect on arachidonic acid levels. Omega-3 PUFAs also reduced surface expression of GPR109A, a human niacin receptor. Furthermore, omega-3 PUFAs also inhibited the niacin-induced increase in cytosolic calcium. Niacin and/or omega-3 PUFAs minimally affected cyclooxygenase-1 activity and had no effect on cyclooxygenase -2 activity. The effects of niacin on PGD₂ generation were further confirmed using Langerhans dendritic cells. Results of the present study indicate that omega-3 PUFAs reduced niacin-induced prostaglandins formation by diminishing the availability of their substrate, as well as reducing the surface expression of niacin receptors. In conclusion, this study suggests that the regular use of omega-3 PUFAs along with niacin can potentially reduce the niacin-induced flushing response in sensitive patients.

Novel LDL-oriented pharmacotherapeutical strategies

Elevated levels of low-density cholesterol (LDL-C) are highly correlated with increased risk of cardiovascular diseases (CVD). Thus, current guidelines have recommended progressively lower LDL-C for cholesterol treatment and CVD prevention as the primary goal of therapy. Even so, some patients in the high risk category fail to achieve recommended LDL-C targets with currently available medications. Thereby, additional pharmaceutical strategies are urgently required. In the review, we aim to provide an overview of both current and emerging LDL-C lowering drugs. As for current available LDL-C lowering agents, attentions are mainly focused on statins, niacin, bile acid sequestrants, ezetimibe, fibrates and omega-3 fatty acids. On the other hand, the emerging drugs differ from mechanisms are including: intervention of cholesterol biosynthesis downstream enzyme (squalene synthase inhibitors), inhibition of lipoprotein assembly (antisense mRNA inhibitors of apolipoprotein B and microsomal transfer protein inhibitors), enhanced lipoprotein clearance (proprotein convertase subtilisin kexin type 9, thyroid hormone analogues), inhibition of intestinal cholesterol absorption (Niemann-Pick C1-like 1 protein and acyl coenzyme A:cholesterol acyltransferase inhibitors) and interrupting enterohepatic circulation (apical sodium-dependent bile acid transporter inhibitors). Several ongoing agents are in their different stages of clinical trials, in expectation of promising antihyperlipidemic drugs. Therefore, alternative drugs monotherapy or in combination with statins will be sufficient to reduce LDL-C concentrations to optimal levels, and a new era for better LDL-C managements is plausible.

Extended release niacin-laropiprant in patients with hypercholesterolemia or mixed dyslipidemias improves clinical parameters

The progression of atherosclerosis remains a major cause of morbidity and mortality. Plaque formation is an immunological response driven by a number of risk factors, and reduction of risk is the primary goal of treatment. The role of LDL-C is well established and statins have proved effective drugs, although the relative risk reduction is only around 30%. The importance of other factors-notably low HDL-C and high TGs-has become increasingly clear and the search for alternative strategies continues. Niacin is particularly effective in achieving normalization of HDL-C but is clinically underutilized due to the side effect of cutaneous flushing. The discovery that flushing is mediated by mechanisms distinct from the lipid-lowering effects has led to the development of combination drugs with reduced side effects. This review considers the evidence regarding the clinical efficacy of extended-release niacin and the DP1 antagonist laropiprant in the treatment of hypercholesterolemia and mixed dyslipidemias.

Combination of niacin and fenofibrate with lifestyle changes improves dyslipidemia and hypoadiponectinemia in HIV patients on antiretroviral therapy: results of "heart positive," a randomized, controlled trial

CONTEXT

HIV patients on antiretroviral therapy (ART) have a unique dyslipidemia [elevated triglycerides and non-high-density lipoprotein-cholesterol (HDL-C), low HDL-C] with insulin resistance (characterized by hypoadiponectinemia).

OBJECTIVE

The aim was to test a targeted, comprehensive, additive approach to treating the dyslipidemia.

DESIGN AND SETTING

We conducted a randomized, double-blind, placebo-controlled, 24-wk trial of lifestyle modification, fenofibrate, and niacin in multiethnic HIV clinics at an academic center.

PARTICIPANTS

Hypertriglyceridemic adult patients were stratified on three combinations of ART classes. Subjects retained at the first measurement (2 wk) after entry were included in the analysis (n = 191).

INTERVENTIONS

Subjects were randomized into five treatment groups: usual care (group 1); low-saturated-fat diet and exercise (D/E; group 2); D/E + fenofibrate (group 3); D/E + niacin (group 4); or D/E + fenofibrate + niacin (group 5).

MAIN OUTCOME MEASURES

We measured changes in fasting triglycerides, HDL-C, and non-HDL-C (primary), and in insulin sensitivity, glycemia, adiponectin, C-reactive protein, energy expenditure, and body composition (secondary). Data were analyzed as a factorial set of treatment combinations using a mixed repeated measures model, last observation carried forward, and complete case approaches (groups 2-5), and as an unstructured set of treatments (groups 1-5).

RESULTS

Fenofibrate improved triglycerides (P = 0.002), total cholesterol (P = 0.02), and non-HDL-C (P = 0.003), whereas niacin improved HDL-C (P = 0.03), and both drugs decreased the total cholesterol-to-HDL-C ratio (P = 0.005-0.01). The combination of D/E, fenofibrate, and niacin provided maximal benefit, markedly reducing triglycerides (-52% compared to usual care; P = 0.003), increasing HDL-C (+12%; P < 0.001), and decreasing non-HDL-C (-18.5%; P = 0.003) and total cholesterol-to-HDL-C ratio (-24.5%; P < 0.001). Niacin doubled adiponectin levels.

CONCLUSIONS

A combination of fenofibrate and niacin with low-saturated-fat D/E is effective and safe in increasing HDL-C, decreasing non-HDL-C and hypertriglyceridemia, and ameliorating hypoadiponectinemia in patients with HIV/ART-associated dyslipidemia.

Combination lipid therapy in type 2 diabetes mellitus

INTRODUCTION

A significant drop in cardiovascular risk has been seen in patients with type 2 diabetes treated with statins. However, this cardiovascular risk remains high, compared with nondiabetic individuals. This is partly due to the typical abnormalities of diabetic dyslipidemia - hypertriglyceridemia and decreased high-density lipoprotein cholesterol (HDL-C) - that are uncontrolled by statins. For this reason, combination lipid therapy may be considered in patients with type 2 diabetes.

AREAS COVERED

This review presents the main reasons for a combination lipid therapy in type 2 diabetes and the effects of several drugs, including fibrates, pioglitazone, niacin and omega 3, on diabetic dyslipidemia and the prevention of cardiovascular events. The real cardiovascular benefit of fibrates in patients with type 2 diabetes is not totally clear, but they may produce a significant benefit in patients with type 2 diabetes and diabetic dyslipidemia (hypertriglyceridemia, low HDL-C). Pioglitazone, which reduces triglycerides and increases HDL-C, has been shown to reduce the risk for major cardiovascular events in type 2 diabetes. Niacin and omega 3 fatty acids have a positive effect on diabetic dyslipidemia, but warrants clinical trials to demonstrate a clear cardiovascular benefit in type 2 diabetes.

EXPERT OPINION

Although combination lipid therapy seems to be useful to control diabetic dyslipidemia, the efficacy of such combined therapies on significantly reducing cardiovascular risk has still to be confirmed by additional clinical trials.

Add-on-Statin Extended Release Nicotinic Acid/Laropiprant but Not the Switch to High-Dose Rosuvastatin Lowers Blood Pressure: An Open-Label Randomized Study

Introduction. Nicotinic acid (NA) and statins have been associated with reductions in blood pressure (BP). Patients and Methods. We recruited 68 normotensive and hypertensive dyslipidemic patients who were treated with a conventional statin dose and had not achieved lipid targets. Patients were randomized to switch to high-dose rosuvastatin (40 mg/day) or to add-on current statin treatment with extended release (ER) NA/laropiprant (1000/20 mg/day for the first 4 weeks followed by 2000/40 mg/day for the next 8 weeks) for 3 months. Results. Switching to rosuvastatin 40 mg/day was not associated with significant BP alterations. In contrast, the addition of ER-NA/laropiprant to current statin treatment resulted in a 7% reduction of systolic BP (from 134 ± 12 to 125 ± 10 mmHg, P < .001 versus baseline and P = .01 versus rosuvastatin group) and a 5% reduction of diastolic BP (from 81 ± 9 to 77 ± 6 mmHg, P = .009 versus baseline and P = .01 versus rosuvastatin group). These reductions were significant only in the subgroup of hypertensives and were independent of the hypolipidemic effects of ER-NA/laropiprant. Conclusions. Contrary to the switch to high-dose rosuvastatin, the addition of ER-NA/laropiprant to statin treatment was associated with significant reductions in both systolic and diastolic BP.

Emerging options in the treatment of dyslipidemias: a bright future?

INTRODUCTION

Hypercholesterolemia is a major risk factor for cardiovascular disease (CVD). Low-density lipoprotein cholesterol (LDL-C) reduction has been demonstrated to decrease CVD-related morbidity and mortality. However, several patients do not reach LDL-C target levels with the currently available lipid lowering agents, particularly statins. Lipid and non-lipid parameters other than LDL-C may account for the residual CVD risk after adequate LDL-C lowering with statins.

AREAS COVERED

This review focuses on the efficacy and safety of emerging drugs aiming at high-density lipoprotein cholesterol (HDL-C) elevation (i.e., recombinant or plasma-derived wild-type apolipoprotein (apo) A-I, apo A-I mimetic peptides, reconstituted mutant HDL, partially delipidated HDL and cholesterol ester transfer protein inhibitors), microsomal triglyceride transfer protein inhibitors and antisense oligonucleotides.

EXPERT OPINION

Several lipid modifying agents in development may potently reduce the residual CVD risk. Ongoing and future studies with clinical outcomes will clarify their efficacy in clinical practice.

Optimizing lipid-lowering therapy in the prevention of coronary heart disease

Optimized lipid-lowering therapy is laid out in guidelines from national and international bodies. Statins are first-line treatment and instituted early in secondary prevention. The challenge in primary prevention is identification of the person at risk. This can be achieved by using scoring systems that assess classical risk factors, and then by adding information from predictive panels of biomarkers related to atherogenic pathways and by noninvasive imaging of vascular beds. At present, outcome trials validate the widespread use of statins in the population but studies of other agents have not generated proof of efficacy. Levels of high-density lipoprotein are related inversely to coronary heart disease risk but, so far, it is unclear if increasing high-density lipoprotein leads to a reduction in risk. Clinical trials on the utility of high-density lipoprotein raising on a background of statin therapy are underway.