Current lipid-altering agents that lower low density lipoprotein cholesterol (LDL-C) primarily through increased hepatic LDL receptor activity include statins, bile acid sequestrants/resins and cholesterol absorption inhibitors such as ezetimibe, plant stanols/sterols, polyphenols, as well as nutraceuticals such as oat bran, psyllium and soy proteins; those currently in development include newer statins, phytostanol analogues, squalene synthase inhibitors, bile acid transport inhibitors and SREBP cleavage-activating protein (SCAP) activating ligands. Other current agents that affect lipid metabolism include nicotinic acid (niacin), acipimox, high-dose fish oils, antioxidants and policosanol, whilst those in development include microsomal triglyceride transfer protein (MTP) inhibitors, acylcoenzyme A: cholesterol acyltransferase (ACAT) inhibitors, gemcabene, lifibrol, pantothenic acid analogues, nicotinic acid-receptor agonists, anti-inflammatory agents (such as Lp-PLA(2) antagonists and AGI1067) and functional oils. Current agents that affect nuclear receptors include PPAR-alpha and -gamma agonists, while in development are newer PPAR-alpha, -gamma and -delta agonists, as well as dual PPAR-alpha/gamma and 'pan' PPAR-alpha/gamma/delta agonists. Liver X receptor (LXR), farnesoid X receptor (FXR) and sterol-regulatory element binding protein (SREBP) are also nuclear receptor targets of investigational agents. Agents in development also may affect high density lipoprotein cholesterol (HDL-C) blood levels or flux and include cholesteryl ester transfer protein (CETP) inhibitors (such as torcetrapib), CETP vaccines, various HDL 'therapies' and upregulators of ATP-binding cassette transporter (ABC) A1, lecithin cholesterol acyltransferase (LCAT) and scavenger receptor class B Type 1 (SRB1), as well as synthetic apolipoprotein (Apo)E-related peptides. Fixed-dose combination lipid-altering drugs are currently available such as extended-release niacin/lovastatin, whilst atorvastatin/amlodipine, ezetimibe/simvastatin, atorvastatin/CETP inhibitor, statin/PPAR agonist, extended-release niacin/simvastatin and pravastatin/aspirin are under development. Finally, current and future lipid-altering drugs may include anti-obesity agents which could favourably affect lipid levels.

Pharmacotherapy for dyslipidaemia – current therapies and future agents

OBJECTIVE:To review the efficacy and safety of fenofibrate in the management of hyperlipidemias.DATA SOURCES:A MEDLINE search (1974–October 1998), Current Contents search, additional references from article bibliographies, and the package insert from the manufacturer were used to identify data for evaluation. Studies evaluating fenofibrate (peer-reviewed publications, package insert data) were considered for inclusion. Abstracts and data on file with the manufacturer were not considered for inclusion.STUDY SELECTION:English-language literature was reviewed to evaluate the pharmacology, pharmacokinetics, clinical use, and tolerability of fenofibrate. Data from animals and in vitro systems were included only when necessary to explain the drug's pharmacology.DATA SYNTHESIS:Micronized fenofibrate is a fibric acid derivative approved by the Food and Drug Administration (FDA) in February 1998 for the treatment of types IV and V hyperlipidemia. Data from the peer-reviewed literature also support the use of fenof...

Micronized Fenofibrate: A New Fibric Acid Hypolipidemic Agent

An elevated low-density lipoprotein (LDL) cholesterol level is a strong predictor of coronary heart disease (CHD) risk. Over the past seven years, equally strong evidence has accumulated that lowering LDL cholesterol with HMG-CoA reductase inhibitors or statins reduces CHD risk and there is now widespread use of these agents for the primary and secondary prevention of CHD. Treatment issues remain regarding the appropriate degree of LDL cholesterol reduction and whether, in people with very high levels, it would be preferable to achieve the LDL cholesterol goal with a powerful statin alone or combined with an agent that lowers LDL cholesterol by a different mechanism. The main focus in the development of novel agents is the patient with low high-density lipoprotein (HDL) cholesterol, usually associated with hypertriglyceridaemia. Already prevalent as a risk factor for CHD, this abnormality has been linked with insulin resistance, which is likely to increase greatly over the next decade, along with increasing obesity and diabetes. Agents that have potent HDL cholesterol raising capacity include cholesteryl ester transfer protein (CETP) inhibitors, retinoid X receptor (RXR) selective agonists, specific peroxisome proliferator-activated receptor (PPAR) agonists and oestrogen-like compounds. Another area of development involves agents that will lower both cholesterol and triglyceride levels, such as partial inhibitors of microsomal triglyceride transfer protein (MTP) and perhaps squalene synthase inhibitors and agonists of AMP kinase. Future emphasis will be on correcting all lipid abnormalities for the prevention of CHD, not just lowering LDL cholesterol.

Novel agents for managing dyslipidaemia.

Fibrates are used in patients with dyslipidemia and high cardiovascular risk. However, information regarding drug response to fibrate has been highly limited. We investigated treatment results and factors associated with triglyceride reduction after fenofibrate therapy using large-scale real-world data. Patients with one or more cardiovascular risk factors, at low-density lipoprotein-cholesterol goal but with triglyceride level ≥150 mg/dL, and undergoing treatment with fenofibrate 135-160 mg for the first time were included in this retrospective observational study. The outcome variable was the percentage changes of TG levels. The achievement rate of triglyceride <150 mg/dL was additionally analyzed. Factors associated with treatment results were also analyzed. Among 2546 patients who were initially screened, 1113 patients were enrolled (median age: 61 years; male: 71%). After median follow-up of 4 months, the median change in triglyceride was -60%, and 49% of the patients reached triglyceride <150 mg/dL. After adjusting for confounding variables, female sex, non-diabetic status, coronary artery disease, lower baseline triglyceride, and no statin use were identified to be independently associated with achievement of triglyceride <150 mg/dL. Among them, female sex, non-diabetic status, and coronary artery disease were also related to median or greater percentage reduction of triglyceride. In conclusion, only half of the study patients reached triglyceride levels <150 mg/dL after real-world fenofibrate therapy. This study indicates that more attention is needed on some subgroups to obtain optimal triglyceride levels when treating with fenofibrate.

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Effect of fenofibrate in 1113 patients at low-density lipoprotein cholesterol goal but high triglyceride levels: Real-world results and factors associated with triglyceride reduction.

Management of dyslipoproteinaemia is one of the key strategies in the prevention of cardiovascular disease. The major target of hypolipidaemic drugs is the reduction of low density lipoprotein (LDL) cholesterol. Lifibrol, a novel lipid-lowering agent, is highly potent in reducing total cholesterol, LDL cholesterol, and apolipoprotein B. Its efficacy in lowering serum triglycerides, lipoprotein(a) and fibrinogen implies additional benefit in the prophylaxis and treatment of coronary heart disease. Thus, lifibrol appears to be a multivalent anti-atherosclerotic agent. The hypolipidaemic properties of lifibrol have been examined in several clinical trials and in various animal models. The mode of action of lifibrol involves at least three mechanisms: lifibrol enhances LDL catabolism by sterol-independent stimulation of LDL receptor activity, reduces cholesterol absorption from the intestine, and slightly decreases hepatic cholesterol biosynthesis. Lifibrol’s lipid-lowering profile and putative mode of action...

Lifibrol: first member of a new class of lipid-lowering drugs?

Objective : We studied possible sex differences of the effect of fenofibrate on serum lipoproteins. Twenty-three patients with primary hypercholesterolaemia (10 postmenopausal women and 13 aged-matched men) were treated with slow-release fenofibrate for 96 weeks. Results : Steady state lipoprotein concentrations were reached after 12 and 24 weeks of treatment in women and men, respectively. During the subsequent follow-up the lipoprotein concentrations remained constant. In women total and low-density lipoprotein (LDL) cholesterol decreased from 299 to 234 mg.dl -1 and from 210 to 151 mg.dl -1 , respectively, and in men from 265 to 233 mg.dl -1 and from 192 to 160 mg.dl -1 . The decrease in triglycerides was also more pronounced in women (-42%) than in men (-18%). High-density lipoprotein (HDL) cholesterol increased significantly in women from 53 to 63 mg.dl -1 but not in men (45 to 50 mg.dl -1 ). Since the changes in LDL and HDL cholesterol occurred in opposite directions, the decrease in LDL/HDL cholesterol ratio was accentuated in both groups. However, this ratio was decreased almost twofold in women (-41%) compared to men (-23%). Although the serum concentrations of fenofibric acid were 1.3-fold higher in women than in men, which was probably due to the higher body weight in men (1.2-fold), this difference can hardly explain the favorable effect on lipoproteins in women. Conclusion : The present study indicates that fenofibrate might be very effective by reducing the concentrations of atherogenic lipoproteins in postmenopausal women.

Differences in the response of serum lipoproteins to fenofibrate between women and men with primary hypercholesterolaemia

Lifibrol is a powerful cholesterol-lowering drug of unknown mechanism of action This investigation was carried out to determine whether the major action of lifibrol is to enhance clearance of low density lipoproteins (LDL) through the LDL-receptor pathway, and if so, whether the drug exerts its action by altering the excretion of bile acids (acidic steroids), the absorption of cholesterol, or the synthesis of cholesterol In a first study, in two patients with complete absence of LDL receptors, lifibrol therapy had essentially no effect on plasma LDL concentrations; in two others who had a marked reduction in LDL-receptor activity, response to the drug was attenuated These findings suggest that lifibrol requires an intact LDL-receptor pathway to exert its action In a second study, in patients with primary moderate hypercholesterolemia, isotope kinetic studies showed that lifibrol enhanced the fractional catabolic rate of LDL-apolipoprotein B (apo B), but had no effect on transport rates of LDL; these observations likewise support the probability that lifibrol acts mainly to increase the activity of the LDL-receptor pathway However, in a third study in hypercholesterolemic patients, lifibrol therapy failed to increase acidic steroid excretion, inhibit cholesterol absorption, or reduce net cholesterol balance Furthermore, lifibrol treatment did not significantly reduce urinary excretion of mevalonic acid In contrast, in a parallel study, simvastatin therapy, which is known to inhibit cholesterol synthesis, gave the expected decrease in net cholesterol balance and reduction in urinary excretion of mevalonic acid Thus, lifibrol, like statins, appears to increase the activity of LDL receptors; but in contrast to findings with statins, it was not possible to detect a significant decreased synthesis of cholesterol, either from balance studies or from urinary excretion of mevalonic acid This finding raises the possibility that lifibrol activates the LDL-receptor pathway through a different mechanisms which remains to be determined

J. von Bergmann

Papers

Differences in the response of serum lipoproteins to fenofibrate between women and men with primary hypercholesterolaemia

Effect of lifibrol on the metabolism of low density lipoproteins and cholesterol

Lifibrol, a potent cholesterol-lowering drug with unknown mechanism(s) of action