Safety and efficacy of colesevelam hydrochloride in combination with fenofibrate for the treatment of mixed hyperlipidemia

Colesevelam - a bile acid sequestrant for treating hypercholesterolemia and improving hyperglycemia

INTRODUCTION

Low density Lipoprotein cholesterol)LDL-C) levels show a clear relationship with cardiovascular disease (CVD). Statins are first line agents to reduce LDL-C and CVD risk. However, combination lipid-lowering therapy is often required to achieve large reductions in LDL-C.

AREA COVERED

Colesevelam HCl is a bile acid sequestrant (BAS), which reduces LDL-C by 16-22% in monotherapy and adds a further 12-14% reduction in LDL-C when combined with other lipid-lowering drugs. Like statins, colesevelam reduces C-reactive protein levels by 16% in monotherapy and additional 6% when added to statins. Colesevelam also reduced HbA_1c by 4mmol/mol (0.5%) when used alone and added to other hypoglycaemic drugs in studies of patients with diabetes .

EXPERT OPINION

Bile acid sequestrants reduce LDL-C and HbA_1c and have some CVD outcome evidence. The uses of these agents are limited in patients with gastrointestinal disease or high triglycerides due to adverse effects on gut function and raising triglycerides and they interfere with the absorption of lipid-soluble drugs. Colesevelam has a higher bile acid binding capacity, and fewer adverse effects than other BAS. Colesevelam may be useful as a third line agent for treatment of hypercholesterolemia with some additional specific benefits on glycemic control.

Hypolipidemic effect of oleanolic acid is mediated by the miR-98-5p/PGC-1β axis in high-fat diet-induced hyperlipidemic mice

Oleanolic acid (OA) is an active component of the traditional Chinese herb Olea europaea L. and has been found to exhibit a significant lipid-lowering effect; however, its direct molecular target is still unknown, which limits its clinical application and the possible structure modification to improve its beneficial functions. In this regard, we carried out the present study to identify potential hepatic targets of OA to mediate its lipid-lowering effect. We found that both acute and chronic OA treatments reduced serum levels of triglycerides, total cholesterol, and LDL cholesterol, and decreased hepatic expression levels of peroxisome proliferator-activated receptor-γ coactivator-1β (PGC-1β), which is an important regulator in maintaining hepatic lipid homeostasis, and its downstream target genes. Of note, liver-specific knockdown of PGC-1β recapitulated the hypolipidemic effects of OA. At the molecular level, OA accelerated mRNA degradation of PGC-1β. Microarray analysis revealed a host of microRNAs that potentially mediate OA-induced PGC-1β mRNA degradation, among which, miR-98-5p significantly inhibited activity of Pgc-1β 3' UTR as well as PGC-1β expression and promoted its mRNA degradation. Conversely, miR-98-5p inhibitors blunted the inhibitory effects of OA on PGC-1β expression. Collectively, our data demonstrated that OA ameliorated hyperlipidemia, likely via regulation of the miR-98-5p/PGC-1β axis.-Chen, S., Wen, X., Zhang, W., Wang, C., Liu, J., Liu, C. Hypolipidemic effect of oleanolic acid is mediated by the miR-98-5p/PGC-1β axis in high-fat diet-induced hyperlipidemic mice.

Expanded colesevelam administration options with oral suspension formulation for patients with diabetes and hypercholesterolemia

INTRODUCTION

Colesevelam HCl (colesevelam) is a bile acid sequestrant initially approved by the US Food and Drug Administration (FDA) in 2000 as an adjunct to diet and exercise to lower elevated low-density lipoprotein cholesterol (LDL-C) levels in adults with primary lipidemia, as monotherapy, or in combination with a statin. More recently, the drug was approved for use in adults with type 2 diabetes mellitus (T2DM) to improve glycemic control. Thus, colesevelam is currently the only single-agent monotherapy approved by the FDA to lower both LDL-C and glycated hemoglobin (A1c) levels in adults with T2DM and elevated LDL-C. Moreover, the formulation options for colesevelam have also expanded since its original approval.

MATERIALS AND METHODS

A Medline search was conducted to provide evidence to support the efficacy and safety for the use of colesevelam tablets or oral suspension preparations when treating patients with lipidemia, T2DM, or both. No limitations were placed on publication date or any other parameter.

RESULTS

Clinical studies have shown that colesevelam is efficacious in lowering LDL-C levels, improving the lipid profile, and improving glycemic control by reducing both A1c and fasting plasma glucose levels in T2DM. Equilibrium and kinetics data show that colesevelam is equivalent in its tablet and oral suspension formulation.

CONCLUSION

Having 2 effective oral routes enhances convenience and improves compliance, both of which contribute to maximal therapeutic outcomes. These compliance benefits are due to the ease and flexibility of preparing the powder in various beverages and the pleasant taste from the inclusion of a low-calorie citrus flavoring.

Role of colesevelam in combination lipid-lowering therapy

Hyperlipidemia is associated with an increased risk of cardiovascular events; reducing low-density lipoprotein cholesterol (LDL-C), the primary target for cholesterol-lowering therapy, lowers the risk for such events. Although bile acid sequestrants were the first class of drugs to show a mortality benefit related to LDL-C lowering, statins are now considered first-line pharmacological therapy for reducing LDL-C levels because of their potency and their remarkable record of successful outcomes studies. Nevertheless, a substantial proportion of patients do not achieve LDL-C goals with statin monotherapy. In addition, because of adverse effects (primarily myopathy), some patients may be unwilling to use or unable to tolerate statin therapy at all or may not tolerate a full therapeutic statin dose. Also, statins may increase risk of new-onset diabetes in patients at high risk for diabetes. Thus, there remains a need for other lipid-lowering drugs to be used in combination with or in place of statins. The purpose of this article is to review available data from the literature on the use of colesevelam, a second-generation bile acid sequestrant, in combination with other lipid-lowering agents. Colesevelam has been studied in combination with statins, niacin, fibrates, and ezetimibe (including some three-drug combinations). An additive reduction in LDL-C was seen with all combinations. Other observed effects of colesevelam in combination with other lipid-lowering drugs include reductions in apolipoprotein (apo) B (with statins, fibrates, ezetimibe, statin plus niacin, or statin plus ezetimibe) and high-sensitivity C-reactive protein (with statins), and increases in apo A-I (with statins, ezetimibe, or statins plus niacin). Triglyceride levels remained relatively unchanged when colesevelam was combined with statins, fibrates, ezetimibe, or statin plus ezetimibe, and decreased with the triple combination of colesevelam, statin, and niacin. Colesevelam offset the negative glycemic effects of statins and niacin in subjects with insulin resistance or impaired glucose tolerance. Colesevelam was generally well tolerated when added to other lipid-lowering therapies in clinical trials, with gastrointestinal effects such as constipation being the predominant adverse events. Since colesevelam is not absorbed and works primarily in the intestine, it has a low potential for systemic metabolic drug-drug interactions with other drugs. Colesevelam has been shown to not interact with the lipid-lowering drugs lovastatin and fenofibrate; where interaction may be anticipated, separating dosing times by 4 h reduces the impact of any interaction. Available data confirms that colesevelam has additive cholesterol-lowering effects when used in combination with other lipid-lowering therapies. Furthermore, in some patient populations, the additional glucose-lowering effect of colesevelam may be beneficial in offsetting hyperglycemic effects of other lipid-lowering drugs.

Relative Efficacy of Antilipemic Agents in Non–High-Density Lipoprotein Cholesterol Reduction

The investigators sought to summarize the percentage reduction in non–high-density lipoprotein cholesterol (non-HDL-C) achieved with various antilipemic regimens and to determine whether certain antilipemic regimens have been proven more effective in lowering non-HDL-C. A search of MEDLINE, International Pharmaceutical Abstracts, and Iowa Drug Information Service Database from 1970 to May 2011 was performed. Criteria were used to exclude studies not published in English, studies with methodology limitations, and studies with variables that may affect efficacy beyond the antilipemic agent administered. Only randomized, controlled trials comparing medications approved by the Food and Drug Administration were reviewed to determine whether significant differences in percentage reduction in non-HDL-C had been observed between different medication regimens. A total of 51 trials reported data that could be used to determine the range of percentage reduction in non-HDL-C achieved by select antilipemic regimens. Of these 51 trials, 38 provided head-to-head comparisons of antilipemic regimens. Rosuvastatin and atorvastatin are the most potent 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) in lowering non-HDL-C. Adding ezetimibe, fibric acid derivatives, and omega-3 fatty acids to antilipemic monotherapy may result in further reduction in non-HDL-C. Subjects with certain characteristics (eg, nonwhite) were not prevalent in these studies.

Colesevelam hydrochloride: evidence for its use in the treatment of hypercholesterolemia and type 2 diabetes mellitus with insights into mechanism of action

Colesevelam hydrochloride is a molecularly engineered, second-generation bile acid sequestrant demonstrating enhanced specificity for bile acids which has been approved for use as adjunctive therapy to diet and exercise as monotherapy or in combination with a β-hydroxymethylglutaryl-coenzyme A reductase inhibitor for the reduction of elevated low-density lipoprotein cholesterol in patients with primary hypercholesterolemia. It is also the only lipid-lowering agent currently available in the United States which has been approved for use as adjunctive therapy in patients with type 2 diabetes mellitus whose glycemia remains inadequately controlled on therapy with metformin, sulfonylurea, or insulin. With the recent emphasis upon drug safety by the Food and Drug Administration and various consumer agencies, it is fitting that the role of nonsystemic lipid-lowering therapies such as bile acid sequestrants – with nearly 90 years of in-class, clinically safe experience – should be reexamined. This paper presents information on the major pharmacologic effects of colesevelam, including a discussion of recent data derived from both in vitro and in vivo rodent and human studies, which shed light on the putative mechanisms involved.

Bile acid sequestrants: more than simple resins

PURPOSE OF REVIEW

Bile acid sequestrants (BAS) have been used for more than 50 years in the treatment of hypercholesterolemia. The last decade, bile acids are emerging as integrated regulators of metabolism via induction of various signal transduction pathways. Consequently, BAS treatment may exert unexpected side-effects. We discuss a selection of recently published studies that evaluated BAS in several metabolic diseases.

RECENT FINDINGS

Recently, an increasing body of evidence has shown that BAS in addition to ameliorating hypercholesterolemia are also effective in improving glycemic control in patients with type 2 diabetes, although the mechanism is not completely understood. Furthermore, some reports suggested using these compounds to modulate energy expenditure. Many of these effects have been related to the local effects of BAS in the intestine by directly binding bile acids in the intestine or indirectly by interfering with signaling processes.

SUMMARY

A substantial effort is being made by researchers to fully define the mechanism by which BAS improve glycemic control in type 2 diabetic patients. A new challenge will be to confirm in clinical trials the recent discoveries coming from animal experiments suggesting a role for bile acids in energy metabolism.

Fenofibrate: a review of its use in dyslipidaemia

Fenofibrate is a fibric acid derivative indicated for the treatment of severe hypertriglyceridaemia and mixed dyslipidaemia in patients who have not responded to nonpharmacological therapies. The lipid-modifying effects of fenofibrate are mediated by the activation of peroxisome proliferator-activated receptor-α. Fenofibrate also has nonlipid, pleiotropic effects (e.g. reducing levels of fibrinogen, C-reactive protein and various pro-inflammatory markers, and improving flow-mediated dilatation) that may contribute to its clinical efficacy, particularly in terms of improving microvascular outcomes. Fenofibrate improves the lipid profile (particularly triglyceride [TG] and high-density lipoprotein-cholesterol [HDL-C] levels) in patients with dyslipidaemia. Compared with statin monotherapy, fenofibrate monotherapy tends to improve TG and HDL-C levels to a significantly greater extent, whereas statins improve low-density lipoprotein-cholesterol (LDL-C) and total cholesterol levels to a significantly greater extent. Fenofibrate is also associated with promoting a shift from small, dense, atherogenic LDL particles to larger, less dense LDL particles. Combination therapy with a statin plus fenofibrate generally improves the lipid profile to a greater extent than monotherapy with either agent in patients with dyslipidaemia and/or type 2 diabetes mellitus or the metabolic syndrome. In the pivotal FIELD and ACCORD trials in patients with type 2 diabetes, fenofibrate did not significantly reduce the risk of coronary heart disease events to a greater extent than placebo, and simvastatin plus fenofibrate did not significantly reduce the risk of major cardiovascular (CV) events to a greater extent than simvastatin plus placebo. However, the risk of some nonfatal macrovascular events and the incidence of certain microvascular outcomes were reduced significantly more with fenofibrate than with placebo in the FIELD trial, and in the ACCORD trial, patients receiving simvastatin plus fenofibrate were less likely to experience progression of diabetic retinopathy than those receiving simvastatin plus placebo. Subgroup analyses in the FIELD and ACCORD Lipid trials indicate that fenofibrate is of the greatest benefit in decreasing CV events in patients with atherogenic dyslipidaemia. Fenofibrate is generally well tolerated when administered alone or in combination with a statin. Thus, in patients with dyslipidaemia, particularly atherogenic dyslipidaemia, fenofibrate is a useful treatment option either alone or in combination with a statin.

Clinical Efficacy of Colesevelam in Type 2 Diabetes Mellitus

Purpose: The clinical experience and role in therapy of colesevelam in type 2 diabetes mellitus (T2DM) is discussed. Summary: Colesevelam HCl is a bile acid sequestrant (BAS) with proven efficacy in reducing elevated low-density lipoprotein cholesterol (LDL-C) in patients with primary hyperlipidemia. Colesevelam HCl gained food and drug administration (FDA) approval in 2008 as an adjunct to diet and exercise to improve glycemic control in adults with T2DM. In randomized controlled studies, colesevelam (add-on therapy with metformin, sulfonylureas, and insulin) has shown significant percentage reductions in glycosylated hemoglobin A1c (HbA1c) ranging from 0.5% to 0.54%. Reductions in LDL-C and non-high-density lipoprotein cholesterol (non-HDL-C) ranging from –12.8% to –16.7% and –4.0% to –10.3%, respectively, were also observed. Although no direct comparisons have been made, the safety and tolerability profile of this agent appears to be better than other BAS, with the most common side effects being gastrointestinal related. Conclusion: Colesevelam is effective as an adjunct to diet and exercise to improve glycemic control in adults with T2DM. Due to its effects upon LDL-C and glycemic parameters and favorable safety profile, colesevelam can play a role in an array of T2DM patients.

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.

Colesevelam: an improved bile acid sequestrant for treating hypercholesterolemia and improving diabetes

There is a well-established association between serum cholesterol and coronary heart disease. Statins are the first-line agents for the treatment of hypercholesterolemia, yet combination therapy is required to achieve the desired reduction in low-density lipoprotein cholesterol (LDL-C). Niacin and bile acid sequestrants were among the first lipid-lowering drugs developed to lower LDL-C and have been established to be effective both in monotherapy and in combination therapy. However, tolerability and compliance issues have limited their use. Colesevelam HCl is the newest bile acid sequestrant and reduces LDL-C by 16-22% in monotherapy and adds 12-14% in combination dual therapy with statins, fibrates and ezetimibe or in triple therapy with statin and ezetimibe. It reduces C-reactive protein levels by 16-19% in monotherapy or by 23% in combination with statins and other lipid-lowering therapies. In addition, it consistently reduces hemoglobin A_1c by 0.5% in addition to other hypoglycemic drugs in studies of patients with diabetes. Compared with other bile acid sequestrants it has a higher bile acid-binding capacity, reduced adverse effects and, therefore, has better compliance. Colesevelam HCl is thus a useful addition to the lipid-lowering formulary as a second-line agent, particularly for patients with metabolic syndrome requiring extra reduction in LDL-C.

The Role of Colesevelam Hydrochloride in Hypercholesterolemia and Type 2 Diabetes Mellitus

Objective:

To evaluate the safety and efficacy of colesevelam hydrochloride for the treatment of hypercholesterolemia and type 2 diabetes mellitus.

Data Sources:

Literature retrieval was accessed through MEDLINE/PubMed (1950–March 2010), Web of Science (1980–March 2010), and International Pharmaceutical Abstracts (1977–March 2010) using the terms colesevelam, dyslipidemia, hypercholesterolemia, and type 2 diabetes mellitus. References from publications identified were reviewed for additional resources. In addition, abstracts presented at the most recent (2009) American Diabetes Association, American Association of Clinical Endocrinologists, and European Association for the Study of Diabetes annual meetings were searched for relevant original research.

Study Selection and Data Extraction:

All articles in English identified from the data sources were evaluated. All relevant studies evaluating the safety and efficacy of colesevelam in hypercholesterolemia and/or type 2 diabetes mellitus were included. Priority was placed on data obtained from human randomized controlled trials.

Data Synthesis:

Seventeen clinical trials were reviewed and evaluated. Of the clinical trials evaluating colesevelam in hypercholesterolemia, 3 evaluated monotherapy, 4 evaluated combination therapy with hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, and 6 evaluated combination therapy with other lipid-lowering therapies. In the type 2 diabetes mellitus trials, colesevelam was evaluated in combination with metformin, sulfonylureas, insulin, and rosiglitazone and sitagliptin. A review of the clinical trials provided evidence that colesevelam monotherapy effectively reduces low-density lipoprotein cholesterol (LDL-C). Additionally, the use of colesevelam in combination with other lipid-lowering therapies further reduces LDL-C. Colesevelam also effectively reduces hemoglobin A1c in patients with type 2 diabetes mellitus. The safety and tolerability of colesevelam appear to be improved from that of older-generation bile acid sequestrants, with adverse effects similar to those with placebo in monotherapy and type 2 diabetes mellitus trials.

Conclusions:

Colesevelam is a safe and effective option for the treatment of hypercholesterolemia and type 2 diabetes mellitus. It can fulfill a useful role in combination with HMG-CoA reductase inhibitors for hypercholesterolemia and should be considered in patients with type 2 diabetes mellitus with concomitant hypercholesterolemia.

Fenofibric acid: a new fibrate approved for use in combination with statin for the treatment of mixed dyslipidemia

The last two to three decades have seen an explosive growth in interest and information regarding cardiovascular disease (CVD) risk assessment and treatment. Evidence for the role of low-density lipoprotein (LDL) in risk has led to a series of clinical guidelines/recommendations on the importance of LDL lowering with statin treatment. There is also substantial evidence on a number of lipoproteins in the initiation and progression of atherosclerosis and CV events. Health care professionals have not embraced easily novel approaches to identifying those at increased risk and more aggressive treatment. This is especially true for non-LDL factors. The use of non-statin drugs such as fibrates has been modest and many health care professionals avoid consideration of combination therapy due to an inordinate fear of toxicity. This review will attempt to provide appropriate background information on lipids/lipoproteins, including non-high density lipoprotein and risk, as well as data available on fibrates and combination pharmacologic therapy. We will review a new agent, TriLipix^® (fenofibric acid), and its potential role in treatment.

Colesevelam hydrochloride for the treatment of type 2 diabetes mellitus

BACKGROUND

Colesevelam hydrochloride is a bile acid sequestrant approved in January 2008 by the US Food and Drug Administration (FDA) for the treatment of adult patients with type 2 diabetes mellitus (DM) in combination with a sulfonylurea, metformin, and/or insulin therapy.

OBJECTIVE

The purpose of this article was to review the pharmacology, pharmacokinetics, efficacy, adverse effects and tolerability, drug-drug interactions, contraindications/precautions, dosage and administration, pharmacoeconomics, and the overall role of colesevelam in the management of adult patients with type 2 DM.

METHODS

A literature search using MEDLINE (1966-October 27, 2008), PubMed (1950-October 27, 2008), Science Direct (1994-October 27, 2008), Web of Science (1980-October 27, 2008), American Diabetes Association Scientific Abstracts (2004-2008), and International Pharmaceutical Abstracts (1970-October 27, 2008) was performed using the term colesevelam. English-language, original research and review articles were examined, and citations from these articles were assessed. Manufacturer prescribing information and the FDA review of the new drug application for colesevelam were also examined.

RESULTS

Colesevelam is a hydrophilic, water-insoluble polymer, with negligible absorption and systemic distribution, that is excreted primarily in the feces. Through a mechanism still under investigation, colesevelam effectively lowers glycosylated hemoglobin (HbA(1c)) when used in combination with a sulfonylurea, metformin, and/or insulin therapy. Three completed, published Phase III clinical trials investigating colesevelam for the treatment of type 2 DM were evaluated for information, data, and conclusions. At dosing of 1.875 g BID or 3.75 g once daily in combination with one of the aforementioned agents versus placebo, reductions in HbA(1c) in all 3 Phase III clinical trials of colesevelam ranged from 0.5% to 0.7% (P < 0.02). In clinical trials, colesevelam was well tolerated, with hypoglycemia occurring in approximately 3% of studied patients.

CONCLUSIONS

When used in combination with a sulfonylurea, metformin, and/or insulin therapy, colesevelam has been reported to significantly reduce HbA(1c) in adult patients with type 2 DM. Colesevelam's role in the management of type 2 DM remains undefined, however; further investigation into its mechanism of action and long-term efficacy and safety should be performed.

Improving glycemic and cholesterol control through an integrated approach incorporating colesevelam - a clinical perspective

Bile sequestrants have been used for almost 50 years to lower low density lipoprotein cholesterol (LDL-C). The advent of colesevelam in 2000 provided a more tolerable add-on LDL-C-lowering agent with an excellent safety record and with likely benefit for coronary heart disease events. Colesevelam lowers LDL-C approximately 15%, and has an additive effect when combined with statin or non-statin lipid-modifying agents. It also tends to increase triglyceride levels. The discovery that bile sequestrants also lower glucose levels led to definitive large-scale clinical trials testing the effect of colesevelam as a dual antihyperglycemic agent with LDL-C-lowering properties in type 2 diabetic subjects on metformin-, sulfonylurea- or insulin-based therapy with inadequate glycemic control. Colesevelam was found to lower hemoglobin A1c (HbA1c) by approximately 0.5% compared to placebo over the 16- to 26-week period, and had similar effects on the lipid profile in these diabetic subjects, as had previously been demonstrated in non-diabetic individuals. Colesevelam was well tolerated, with constipation being the most common adverse effect, and did not cause weight gain or excessive hypoglycemia. Colesevelam thus combines antihyperglycemic action with LDL-C-lowering properties, and should be useful in the management of type 2 diabetes.

Update on the clinical utility of fenofibrate in mixed dyslipidemias: mechanisms of action and rational prescribing

Mixed dyslipidemia is a common lipid disorder characterized by the presence of an atherogenic lipoprotein phenotype due to abnormalities in various atherogenic and anti-atherogenic lipoproteins. Despite the link between the decrease of LDL-cholesterol by statin treatment and the prevention of cardiovascular disease, a high residual risk is observed in statin trials. This residual risk is partly explained by lipoprotein abnormalities other than LDL. Fenofibrate exerts a favorable effect on the atherogenic lipid profile of mixed dyslipidemia and can effectively reduce cardiovascular disease in patients with mixed dyslipidemia. Fenofibrate may offer important treatment alternatives as a second-line therapy in several circumstances: in combination with a statin for patients with mixed dyslipidemias not at goals on statin mono-therapy; in monotherapy for patients intolerant or with contraindication to statin therapy; and in combination with other drugs (ezetimibe, colesevelam) for patients with mixed dyslipidemias, known intolerance, or contraindication to statin and not at goals on fenofibrate monotherapy. However, the role of fenofibrate-statin therapy and of other therapies involving fenofibrate in cardiovascular risk reduction strategies remains to be established.

Fenofibrate: treatment of hyperlipidemia and beyond

Fenofibrate is a PPAR-alpha agonist indicated for the treatment of hypertriglyceridemia and mixed dyslipidemia, and is approved for the treatment of hypercholesterolemia, lipid abnormalities commonly observed in patients at high risk of cardiovascular disease, including Type 2 diabetes and/or metabolic syndromes. Treatment with fenofibrate lowers triglycerides, raises HDL-cholesterol and decreases concentrations of small LDL-cholesterol particles and apolipoprotein B. Fenofibrate is particularly effective for reducing postprandial VLDL and LDL particle concentrations, and the increased oxidative stress and inflammatory response that occurs after a fatty meal. In addition, nonlipid pleiotropic effects mediated by PPAR-alpha are likely to contribute to the reduction in atherosclerosis progression and cardiovascular events, and have beneficial effects on diabetes-related microvascular diseases. While current approaches to treating dyslipidemia to prevent cardiovascular diseases focus on statin therapy, it is increasingly clear that substantial residual risk persists. The clinical significance of combination therapy with fenofibrate and a statin to macrovascular and microvascular risk is being evaluated in a large outcomes study.

Treatment of hyperlipidaemia with fenofibrate and related fibrates

BACKGROUND

Fenofibrate is the most widely used fibrate. Its efficacy and tolerability in the treatment of hypertriglyceridaemia and combined hyperlipidaemia have been demonstrated in several clinical trials.

OBJECTIVE

To review the pharmacology, lipid-lowering and extra-lipid effects of fenofibrate and to preview ABT-335, an investigational new fenofibric acid molecule.

RESULTS

The effects of fenofibrate are mediated through the active metabolite fenofibric acid, and are described in detail in the paper. ABT-335 is a salt of fenofibric acid and, unlike fenofibrate, does not require first pass metabolism to the active moiety. ABT-335 is being developed for combination use with statins, and has recently completed three large Phase III randomised controlled trials in which the efficacy and safety of ABT-335 in combination with the three most commonly prescribed statins, atorvastatin, simvastatin and rosuvastatin, was evaluated in patients with mixed dyslipidaemia.

CONCLUSION

ABT-335 in combination with statins may provide a safe and efficacious treatment modality that enables achievement of several therapeutic goals in patients with mixed dyslipidaemia who have high cardiovascular risk.

Safety considerations with gastrointestinally active lipid-lowering drugs

Gastrointestinally active agents such as cholesterol absorption inhibitors (CAIs) (eg, ezetimibe) and bile acid sequestrants (BAS) (the resins cholestyramine and colestipol, or colesevelam, a nonabsorbable polymer) offer important options for lipid-lowering therapy. Ezetimibe is a novel CAI that inhibits the absorption of dietary and biliary cholesterol without affecting the absorption of triglycerides or fat-soluble vitamins. In clinical trials, there has been no evidence of increased rates of myopathy or rhabdomyolysis associated with ezetimibe, whether in use as monotherapy or in a combination with statin therapy, although there exist case reports of possible ezetimibe-associated myopathy. Ezetimibe alone does not appear to increase liver transaminase levels significantly, but the coadministration of a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) with ezetimibe marginally increases this risk. However, reported increases in liver enzymes have not been associated with clinically meaningful symptoms and often return to baseline levels after the discontinuation of therapy or with continued treatment. To date, no cases of liver failure, liver transplantation, or death have been reported. BAS have been used clinically since the 1960s for lowering low-density lipoprotein cholesterol. Because they are not absorbed from the gastrointestinal tract into the blood, these agents do not contact most body organs and are therefore systemically safe. However, case reports and pharmacokinetic data disclose 3 kinds of adverse effects: (1) the decreased absorption of concomitant medications and sometimes of certain vitamins; (2) the physicochemical alteration of intestinal contents leading to constipation and, very rarely, intestinal obstruction; and (3) modest increases in plasma triglyceride levels due to the alteration of hepatic lipid metabolism. The newest BAS, colesevelam, has greater specificity for bile acids compared with the older agents cholestyramine and colestipol, eliminating most drug interactions and reducing the tendency for constipation. Overall, CAIs and BAS have excellent systemic safety profiles when used alone or in combination with other lipid-lowering drugs.

Fenofibrate

Fenofibrate is a fibric acid derivative indicated for use in the treatment of primary hypercholesterolaemia, mixed dyslipidaemia and hypertriglyceridaemia in adults who have not responded to nonpharmacological measures. Its lipid-modifying effects are mediated by activation of peroxisome proliferator-activated receptor-alpha. Fenofibrate also has nonlipid (i.e. pleiotropic) effects (e.g. it reduces fibrinogen, C-reactive protein and uric acid levels and improves flow-mediated dilatation). Fenofibrate improves lipid levels (in particular triglyceride [TG] and high-density lipoprotein-cholesterol [HDL-C] levels) in patients with primary dyslipidaemia. Its lipid-lowering profile means that fenofibrate is particularly well suited for use in atherogenic dyslipidaemia (characterised by high TG levels, low HDL-C levels and small, dense low-density lipoprotein [LDL] particles), which is commonly seen in patients with the metabolic syndrome and type 2 diabetes mellitus. Indeed, fenofibrate improves the components of atherogenic dyslipidaemia in patients with these conditions, including a shift from small, dense LDL particles to larger, more buoyant LDL particles. Greater improvements in lipid levels are seen when fenofibrate is administered in combination with an HMG-CoA reductase inhibitor (statin) or in combination with ezetimibe, compared with monotherapy with these agents. In the DAIS study, fenofibrate significantly slowed the angiographic progression of focal coronary atherosclerosis in patients with type 2 diabetes. In terms of clinical outcomes, although no significant reduction in the risk of coronary events was seen with fenofibrate in the FIELD trial in patients with type 2 diabetes, treatment was associated with a significantly reduced risk of total cardiovascular disease (CVD) events, primarily through the prevention of non-fatal myocardial infarction and coronary revascularisation. Subgroup analyses revealed significant reductions in total CVD events and coronary heart disease events in patients with no previous CVD, suggesting a potential role for primary prevention with fenofibrate in patients with early type 2 diabetes. Improvements were also seen in microvascular outcomes with fenofibrate in the FIELD trial. Fenofibrate is generally well tolerated, both as monotherapy and when administered in combination with a statin. Combination therapy with fenofibrate plus a statin appears to be associated with a low risk of rhabdomyolysis; no cases of rhabdomyolysis were reported in patients receiving such therapy in the FIELD trial. Thus, fenofibrate is a valuable lipid-lowering agent, particularly in patients with atherogenic dyslipidaemia.

Lipoprotein effects of combined ezetimibe and colesevelam hydrochloride versus ezetimibe alone in hypercholesterolemic subjects: a pilot study

Two drug classes act in the intestine to lower cholesterol. Ezetimibe inhibits cholesterol absorption, whereas bile acid-binding resins enhance cholesterol excretion via enhanced conversion to bile acids. Combining these 2 classes may be beneficial, but cholestyramine binds ezetimibe, and the combined effect of colesevelam hydrochloride and ezetimibe was little studied. The aim of the study was to determine if adding colesevelam HCl to ezetimibe provides additional lowering of low-density lipoprotein- and apolipoprotein B-containing lipoproteins or alters ezetimibe levels. Twenty subjects with low-density lipoprotein cholesterol (LDL-C) levels of 130 mg/dL or higher were enrolled and taught a National Cholesterol Education Program Step I diet. At a second baseline visit, lipoproteins were measured and subjects were randomly allocated to (1) ezetimibe 10 mg daily with placebo colesevelam HCl twice daily (E) or (2) ezetimibe 10 mg daily with 1.875 g colesevelam HCl twice daily (E + C). Lipoproteins were measured 6 and 12 weeks after initiating treatment. Baseline characteristics (mean +/- SD) were statistically indistinguishable in E vs E + C: LDL-C (mg/dL), 167 +/- 26 and 158 +/- 27; triglyceride, 134 +/- 75 and 140 +/- 67; and BMI, 29.4 +/- 4.9 and 27.8 +/- 6.6 kg/m(2), respectively. Percent changes after 12 weeks in E vs E + C were as follows: LDL-C, -24 +/- 12 vs -30 +/- 11 (P = .102); triglyceride, -19 +/- 34 vs 36 +/- 85 (P = .054; at 6 weeks, P = .009); total cholesterol, -19 +/- 9 vs -15 +/- 8 (P = .50); non-high-density lipoprotein cholesterol, -25 +/- 10 vs -21 +/- 11 (P = .70); apolipoprotein B, -31 +/- 14 vs -22 +/- 14 (P = .41). Plasma ezetimibe levels at 12 weeks were 21% lower in E + C vs E, a nonsignificant difference (P = .54). In conclusion, in the short term, colesevelam HCl may not consistently add cholesterol-lowering benefit to ezetimibe. This observation requires confirmation.

Effects of colesevelam hydrochloride (WelChol) on biomarkers of inflammation in patients with mild hypercholesterolemia

Inflammation is pivotal in atherogenesis. High-sensitivity C-reactive protein (hs-CRP), the prototypic marker of inflammation, has been shown to predict cardiovascular events. Colesevelam hydrochloride (HCl) (WelChol, Sankyo Pharma Incorporated, Parsippany, New Jersey), a specifically engineered bile acid sequestrant, has been shown to be effective in lowering low-density lipoprotein (LDL) cholesterol levels in monotherapy and in combination with statins or fenofibrate. Previously, we have shown that statins lower hs-CRP levels; however, a paucity of data is available examining the effect of colesevelam HCl on hs-CRP levels. The aim of this study was to examine the effect of colesevelam HCl therapy (3.75 g/day for 6 weeks) on hs-CRP in patients with mild hypercholesterolemia in a randomized, double-blind, placebo-controlled study. Twenty-five subjects on colesevelam HCl and 23 subjects on placebo completed the study. The median baseline hs-CRP levels for the treatment and placebo groups are 3.4 and 3.1 mg/L, respectively. Colesevelam HCl therapy resulted in a significant reduction in LDL cholesterol levels (p < 0.001). No significant changes were found in total triglyceride or high-density lipoprotein cholesterol levels between the 2 groups. Furthermore, colesevelam HCl therapy resulted in a significant reduction in hs-CRP levels compared with baseline and placebo (15.9% and 18.7% median reduction, respectively, p < 0.025). No correlation was found between LDL cholesterol lowering and hs-CRP lowering (r = 0.3). In conclusion, our results show that colesevelam HCl monotherapy significantly lowered hs-CRP levels in a double-blind, placebo-controlled study.

Clinical utility of bile acid sequestrants in the treatment of dyslipidemia: a scientific review

Bile acid sequestrants (BAS) continue to command a position in the treatment of dyslipidemias 25 years after their introduction. Partial diversion of the enterohepatic circulation using BAS depletes the endogenous bile acid pool by approximately 40%, thus stimulating an increase in bile acid synthesis from cholesterol, which lowers low-density lipoprotein cholesterol (LDL-C) by 15 to 26%. Three BAS are currently used for treating hypercholesterolemia in the United States: the conventional sequestrants, cholestyramine and colestipol, and the specifically engineered BAS, colesevelam hydrochloride (HCl). Compared with conventional BAS, colesevelam HCl has enhanced specificity, greater affinity, and higher capacity for binding bile acids, due to its polymer structure engineered for bile acid sequestration. BAS are not absorbed by the intestine and thus have no systemic drug-drug interactions, but may interfere with the absorption of some drugs. Although BAS monotherapy effectively lowers LDL-C, combination therapy, especially with BAS and statins, is becoming increasingly common due to complementary mechanisms of action. Low-dose statin plus BAS combinations lead to greater or similar LDL-C reductions compared with high-dose statin monotherapy and may have a better safety profile. Combinations of BAS with nonstatin lipid-lowering agents, including niacin, fibrates, and cholesterol absorption inhibitors, may be useful in those patients who require intensive lipid-lowering, but are statin intolerant. BAS treatment can significantly reduce coronary artery disease (CAD) progression and the risk of CAD-associated outcomes. It is also becoming clear that BAS and other therapies that manipulate the bile acid synthetic pathway may have clinically useful therapeutic effects on other metabolic disorders including type 2 diabetes.

Fenofibrate: a novel formulation (Triglide) in the treatment of lipid disorders: a review

Cardiovascular disease is the major cause of mortality worldwide and accounts for approximately 40% of all deaths. Dyslipidemia is one of the primary causes of atherosclerosis and effective interventions to correct dyslipidemia should form an integral component of any strategy aimed at preventing cardiovascular disease. Fibrates have played a major role in the treatment of hyperlipidemia for more than two decades. Fenofibrate is one of the most commonly used fibrates worldwide. Since fenofibrate was first introduced in clinical practice, a major drawback has been its low bioavailability when taken under fasting conditions. Insoluble Drug Delivery-Microparticle fenofibrate is a new formulation that has an equivalent extent of absorption under fed or fasting conditions. In this review, we will discuss the clinical pharmacology of fenofibrate, with particular emphasis on this novel formulation, as well as its lipid-modulating and pleiotropic actions. We will also analyze the major trial that evaluated fibrates for primary and secondary prevention of cardiovascular disease, the safety and efficacy profile of fibrate-statin combination treatment, and the current recommendations regarding the use of fibrates in clinical practice.