Efficacy and safety of combination simvastatin and colesevelam in patients with primary hypercholesterolemia

Antihyperlipidemic Treatment Options in Statin Resistance and Intolerance

Cardiovascular disease is the global leading cause of death and hypercholesterolemia is implicated as one of its top contributors. Moreover, there is growing recognition that lower low-density lipoprotein cholesterol levels offer greater protection against cardiovascular disease. Statins are the first-line lipid-lowering agents for both primary and secondary prevention of cardiovascular disease in patients with hypercholesterolemia. However, statin resistance and intolerance lead to undertreatment in patients who would likely derive the most benefit from antihyperlipidemic drugs. Several non-statin therapies are increasingly prescribed to such patients, most commonly ezetimibe and the PCSK9 monoclonal antibodies, but numerous other options have been developed in recent years and investigations into new therapies are ongoing. The use of these non-statin therapies requires the clinician to take a highly personalized approach to cholesterol reduction in complex patients. In this review, we describe current non-statin options for statin-resistant and statin-intolerant patients in addition to areas of active research.

2023 China Guidelines for Lipid Management

Atherosclerotic cardiovascular disease (ASCVD) is the leading cause of death among urban and rural residents in China, and elevated low-density lipoprotein cholesterol (LDL-C) is a risk factor for ASCVD. Considering the increasing burden of ASCVD, lipid management is of the utmost importance. In recent years, research on blood lipids has made breakthroughs around the world, hence a revision of China guidelines for lipid management is imperative, especially since the target lipid levels in the general population vary in respect to the risk of ASCVD. The level of LDL-C, which can be regarded as appropriate in a population without frisk factors, can be considered abnormal in people at high risk of developing ASCVD. As a result, the "Guidelines for the prevention and treatment of dyslipidemia" were adapted into the "China Guidelines for Lipid Management" (henceforth referred to as the new guidelines) by an Experts' committee after careful deliberation. The new guidelines still recommend LDL-C as the primary target for lipid control, with CVD risk stratification to determine its target value. These guidelines recommend that moderate intensity statin therapy in adjunct with a heart-healthy lifestyle, be used as an initial line of treatment, followed by cholesterol absorption inhibitors or/and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, as necessary. The new guidelines provide guidance for lipid management across various age groups, from children to the elderly. The aim of these guidelines is to comprehensively improve the management of lipids and promote the prevention and treatment of ASCVD by guiding clinical practice.

2023 Chinese guideline for lipid management

Atherosclerotic cardiovascular disease (ASCVD) is the leading cause of death among urban and rural residents in China, and elevated low-density lipoprotein cholesterol (LDL-C) is a risk factor for ASCVD. Considering the increasing burden of ASCVD, lipid management is of the utmost importance. In recent years, research on blood lipids has made breakthroughs around the world, hence a revision of Chinese guideline for lipid management is imperative, especially since the target lipid levels in the general population vary in respect to the risk of ASCVD. The level of LDL-C, which can be regarded as appropriate in a population without frisk factors, can be considered abnormal in people at high risk of developing ASCVD. As a result, the "Guidelines for the prevention and treatment of dyslipidemia" were adapted into the "Chinese guideline for Lipid Management" (henceforth referred to as the new guidelines) by an Experts' committee after careful deliberation. The new guidelines still recommend LDL-C as the primary target for lipid control, with cardiovascular disease (CVD) risk stratification to determine its target value. These guidelines recommend that moderate intensity statin therapy in adjunct with a heart-healthy lifestyle, be used as an initial line of treatment, followed by cholesterol absorption inhibitors or/and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, as necessary. The new guidelines provide guidance for lipid management across various age groups, from children to the elderly. The aim of these guidelines is to comprehensively improve the management of lipids and promote the prevention and treatment of ASCVD by guiding clinical practice.

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.

Modulation of Bile Acid Metabolism to Improve Plasma Lipid and Lipoprotein Profiles

New drugs targeting bile acid metabolism are currently being evaluated in clinical studies for their potential to treat cholestatic liver diseases, non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). Changes in bile acid metabolism, however, translate into an alteration of plasma cholesterol and triglyceride concentrations, which may also affect cardiovascular outcomes in such patients. This review attempts to gain insight into this matter and improve our understanding of the interactions between bile acid and lipid metabolism. Bile acid sequestrants (BAS), which bind bile acids in the intestine and promote their faecal excretion, have long been used in the clinic to reduce LDL cholesterol and, thereby, atherosclerotic cardiovascular disease (ASCVD) risk. However, BAS modestly but consistently increase plasma triglycerides, which is considered a causal risk factor for ASCVD. Like BAS, inhibitors of the apical sodium-dependent bile acid transporter (ASBTi’s) reduce intestinal bile acid absorption. ASBTi’s show effects that are quite similar to those obtained with BAS, which is anticipated when considering that accelerated faecal loss of bile acids is compensated by an increased hepatic synthesis of bile acids from cholesterol. Oppositely, treatment with farnesoid X receptor agonists, resulting in inhibition of bile acid synthesis, appears to be associated with increased LDL cholesterol. In conclusion, the increasing efforts to employ drugs that intervene in bile acid metabolism and signalling pathways for the treatment of metabolic diseases such as NAFLD warrants reinforcing interactions between the bile acid and lipid and lipoprotein research fields. This review may be considered as the first step in this process.

A Meta-Analysis Assessing Additional LDL-C Reduction from Addition of a Bile Acid Sequestrant to Statin Therapy

BACKGROUND

Statins are the first-line therapy for reducing low-density lipoprotein cholesterol (LDL-C). However, there are secondary prevention patients who are either intolerant to maximal statin therapy or do not get adequate effects from a high-intensity statin. While data exist for the additional LDL-C-lowering effects of ezetimibe, there are no data on additional LDL-C lowering of bile acid sequestrants when combined with statin therapy. The purpose of this study was to quantify the LDL-C-lowering effects of bile acid sequestrants when added to statin therapy.

METHODS

Databases (Medline via PubMed, Embase, and the Cochrane Library) were searched for randomized controlled trials comparing statin therapy to statin therapy with the addition of bile acid sequestrants. Nine studies were included in the meta-analysis. A meta-regression was performed to estimate the mean difference in LDL-C between the 2 groups.

RESULTS

Without controlling for other variables, data suggest that combining statin with bile acid sequestrant increases the percentage change in LDL-C by 16.2 points, on average, compared with statin use alone.

CONCLUSION

In patients unable to tolerate an adequate statin dosage, bile acid sequestrants offer a viable alternative with additional LDL-C-lowering benefit.

Lipoproteins and lipids in cardiovascular disease: from mechanistic insights to therapeutic targeting

With cardiovascular disease being the leading cause of morbidity and mortality worldwide, effective and cost-efficient therapies to reduce cardiovascular risk are highly needed. Lipids and lipoprotein particles crucially contribute to atherosclerosis as underlying pathology of cardiovascular disease and influence inflammatory processes as well as function of leukocytes, vascular and cardiac cells, thereby impacting on vessels and heart. Statins form the first-line therapy with the aim to block cholesterol synthesis, but additional lipid-lowering drugs are sometimes needed to achieve low-density lipoprotein (LDL) cholesterol target values. Furthermore, beyond LDL cholesterol, also other lipid mediators contribute to cardiovascular risk. This review comprehensively discusses low- and high-density lipoprotein cholesterol, lipoprotein (a), triglycerides as well as fatty acids and derivatives in the context of cardiovascular disease, providing mechanistic insights into their role in pathological processes impacting on cardiovascular disease. Also, an overview of applied as well as emerging therapeutic strategies to reduce lipid-induced cardiovascular burden is provided.

Berberine Promotes OATP1B1 Expression and Rosuvastatin Uptake by Inducing Nuclear Translocation of FXR and LXRα

Berberine, a quinoline alkaloid, can be used in combination with statins to enhance hypolipidemic effects and reduce the dose and side effects of statins. The hypolipidemic effects of statins in the liver are mainly regulated by organic anion transporting polypeptides (OATPs), and the expression of OATPs is regulated by nuclear receptors. Berberine has been reported to affect nuclear receptors. However, whether berberine affects the uptake of statins by regulating nuclear receptor-mediated expression of OATPs remains to be determined. The aim of this study was to investigate the effects of berberine on the expression of OATP1B1 in HepG2 and explore the underlying mechanism. In HepG2 cells, 10-50 μM berberine significantly increased the uptake of rosuvastatin by inducing the expression of OATP1B1 mRNA and protein. Dual-Luciferase reporter assay showed that luciferase activity of hFXR and hLXRα activated OATP1B1 promoter was increased by 2.5-50 μM berberine in a concentration-dependent manner, with half-maximal effective concentration (EC₅₀) of 12.19 ± 0.86 and 32.15 ± 2.32 μM, respectively. In addition, after silencing FXR or LXRα by small interfering RNA (siRNA), berberine-induced OATP1B1 expression was significantly attenuated. Western blot analysis of FXR and LXRα protein levels in the cytoplasm and nucleus of HepG2 cells after treatment with berberine showed that berberine induced nuclear translocation and activation of FXR and LXRα. In conclusion, berberine-induced nuclear translocation of FXR and LXRα could activate OATP1B1 promoter, resulting in enhanced expression of OATP1B1 and increased uptake of rosuvastatin.

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY GUIDELINES FOR MANAGEMENT OF DYSLIPIDEMIA AND PREVENTION OF CARDIOVASCULAR DISEASE

OBJECTIVE

The development of these guidelines is mandated by the American Association of Clinical Endocrinologists (AACE) Board of Directors and American College of Endocrinology (ACE) Board of Trustees and adheres with published AACE protocols for the standardized production of clinical practice guidelines (CPGs).

METHODS

Recommendations are based on diligent reviews of the clinical evidence with transparent incorporation of subjective factors, according to established AACE/ACE guidelines for guidelines protocols.

RESULTS

The Executive Summary of this document contains 87 recommendations of which 45 are Grade A (51.7%), 18 are Grade B (20.7%), 15 are Grade C (17.2%), and 9 (10.3%) are Grade D. These detailed, evidence-based recommendations allow for nuance-based clinical decision-making that addresses multiple aspects of real-world medical care. The evidence base presented in the subsequent Appendix provides relevant supporting information for Executive Summary Recommendations. This update contains 695 citations of which 203 (29.2 %) are EL 1 (strong), 137 (19.7%) are EL 2 (intermediate), 119 (17.1%) are EL 3 (weak), and 236 (34.0%) are EL 4 (no clinical evidence).

CONCLUSION

This CPG is a practical tool that endocrinologists, other health care professionals, health-related organizations, and regulatory bodies can use to reduce the risks and consequences of dyslipidemia. It provides guidance on screening, risk assessment, and treatment recommendations for a range of individuals with various lipid disorders. The recommendations emphasize the importance of treating low-density lipoprotein cholesterol (LDL-C) in some individuals to lower goals than previously endorsed and support the measurement of coronary artery calcium scores and inflammatory markers to help stratify risk. Special consideration is given to individuals with diabetes, familial hypercholesterolemia, women, and youth with dyslipidemia. Both clinical and cost-effectiveness data are provided to support treatment decisions.

ABBREVIATIONS

4S = Scandinavian Simvastatin Survival Study A1C = glycated hemoglobin AACE = American Association of Clinical Endocrinologists AAP = American Academy of Pediatrics ACC = American College of Cardiology ACE = American College of Endocrinology ACS = acute coronary syndrome ADMIT = Arterial Disease Multiple Intervention Trial ADVENT = Assessment of Diabetes Control and Evaluation of the Efficacy of Niaspan Trial AFCAPS/TexCAPS = Air Force/Texas Coronary Atherosclerosis Prevention Study AHA = American Heart Association AHRQ = Agency for Healthcare Research and Quality AIM-HIGH = Atherothrombosis Intervention in Metabolic Syndrome With Low HDL/High Triglycerides trial ASCVD = atherosclerotic cardiovascular disease ATP = Adult Treatment Panel apo = apolipoprotein BEL = best evidence level BIP = Bezafibrate Infarction Prevention trial BMI = body mass index CABG = coronary artery bypass graft CAC = coronary artery calcification CARDS = Collaborative Atorvastatin Diabetes Study CDP = Coronary Drug Project trial CI = confidence interval CIMT = carotid intimal media thickness CKD = chronic kidney disease CPG(s) = clinical practice guideline(s) CRP = C-reactive protein CTT = Cholesterol Treatment Trialists CV = cerebrovascular CVA = cerebrovascular accident EL = evidence level FH = familial hypercholesterolemia FIELD = Secondary Endpoints from the Fenofibrate Intervention and Event Lowering in Diabetes trial FOURIER = Further Cardiovascular Outcomes Research with PCSK9 Inhibition in Subjects With Elevated Risk trial HATS = HDL-Atherosclerosis Treatment Study HDL-C = high-density lipoprotein cholesterol HeFH = heterozygous familial hypercholesterolemia HHS = Helsinki Heart Study HIV = human immunodeficiency virus HoFH = homozygous familial hypercholesterolemia HPS = Heart Protection Study HPS2-THRIVE = Treatment of HDL to Reduce the Incidence of Vascular Events trial HR = hazard ratio HRT = hormone replacement therapy hsCRP = high-sensitivity CRP IMPROVE-IT = Improved Reduction of Outcomes: Vytorin Efficacy International Trial IRAS = Insulin Resistance Atherosclerosis Study JUPITER = Justification for the Use of Statins in Primary Prevention: An Intervention Trial Evaluating Rosuvastatin LDL-C = low-density lipoprotein cholesterol Lp-PLA2 = lipoprotein-associated phospholipase A2 MACE = major cardiovascular events MESA = Multi-Ethnic Study of Atherosclerosis MetS = metabolic syndrome MI = myocardial infarction MRFIT = Multiple Risk Factor Intervention Trial NCEP = National Cholesterol Education Program NHLBI = National Heart, Lung, and Blood Institute PCOS = polycystic ovary syndrome PCSK9 = proprotein convertase subtilisin/kexin type 9 Post CABG = Post Coronary Artery Bypass Graft trial PROSPER = Prospective Study of Pravastatin in the Elderly at Risk trial QALY = quality-adjusted life-year ROC = receiver-operator characteristic SOC = standard of care SHARP = Study of Heart and Renal Protection T1DM = type 1 diabetes mellitus T2DM = type 2 diabetes mellitus TG = triglycerides TNT = Treating to New Targets trial VA-HIT = Veterans Affairs High-Density Lipoprotein Cholesterol Intervention Trial VLDL-C = very low-density lipoprotein cholesterol WHI = Women's Health Initiative.

Effectiveness and safety of combinational therapy compared with intensified statin monotherapy in patients with coronary heart disease

Reducing the plasma levels of low-density lipoprotein-cholesterol (LDL-C) is critical for patients with coronary heart disease (CHD). Conventional treatment with statins alone may not achieve the goal of lowering LDL-C due to drug intolerance or resistance. The present study evaluated the effectiveness and safety of combining statin with another lipid-lowering agent in the management of dyslipidemia in CHD patients. A total of 180 patients with CHD were divided into three therapeutic groups (n=60 in each): Statin/colesevelam group (20 mg atorvastatin and 10 mg colesevelam daily), statin/ezetimibe group (20 mg atorvastatin and 10 mg ezetimibe daily) and high-intensity statin monotherapy group (30 mg atorvastatin daily). The baseline plasma lipid levels were measured. The duration of the treatment was eight weeks and the side effects were noted at one year's follow-up. After eight weeks' treatment, the mean plasma level of LDL-C was reduced by 45.2, 44.8 and 30.0% in the statin/colesevelam, statin/ezetimibe and statin monotherapy group, respectively. The reduction of LDL-C in the combinational therapy groups was greater than that in the statin monotherapy group (P<0.05). The proportion of patients achieving the goal of lowering LDL-C in the combinational therapy groups was higher than that in the statin monotherapy group. The effectiveness of reducing lipids was similar in the two combinational statin/colesevelam and statin/ezetimibe groups. Rates of adverse events were not significantly different among the three groups. In conclusion, statins combined with colesevelam or ezetimibe were more effective in reducing plasma LDL-C levels than high-intensity statin monotherapy. This combinational therapeutic strategy may be an alternative for patients that are resistant or intolerant to statins.

The effects of additional ezetimibe treatment to baseline rosuvastatin on circulating PCSK9 among patients with stable angina

BACKGROUND

Blood lipid management is one of the effective strategies for coronary heart disease, and statins are the first-line lipid-lowering drugs. Low density lipoprotein cholesterol (LDL-C) drop brings about cardioprotective effects. Proprotein convertase subtilisin kexin type 9 (PCSK9) is known to increase LDL-C, thus hazarding LDL-C reduction-induced benefits. To date, how PCSK9 responds to various lipid-lowering strategies has not been fully clarified.

METHODS

This study involves patients with stable angina and aims to explore and clarify the short-term impacts of rosuvastatin and ezetimibe, alone or in combination, on circulating PCSK9. A total of 68 patients with stable angina were enrolled and 60 eligible patients were randomly assigned into 3 groups (20 subjects in each). Patients in different groups were treated for a period of 14 days with rosuvastatin 10 mg/d, ezetimibe 10 mg/d, and rosuvastatin 10 mg/d plus ezetimibe 10 mg/d, respectively. Concentrations of blood LDL-C and PCSK9 levels were measured at baseline and at the 14^th day after treatment.

RESULTS

Both rosuvastatin and ezetimibe could reduce the LDL-C levels, and rosuvastatin displayed a stronger cholesterol-lowering effect than ezetimibe. Moreover, when combined, they yielded even greater efficacy in lowering LDL-C, as compared with either rosuvastatin or ezetimibe mono-treatment (P<0.05). Rosuvastatin therapy (alone or combined with ezetimibe) caused significant rise in circulating PCSK9. Nevertheless, no significant growth of PCSK9 levels (P=0.558) was observed during ezetimibe treatment. At the 14^th day, no difference in PCKS9 levels was observed between the rosuvastatin group and the combination-therapy group (P=0.906).

CONCLUSIONS

Rosuvastatin plus ezetimibe therapy is more effective in reducing LDL-C levels as compared with either rosuvastatin or ezetimibe mono-medication. Meanwhile, such combination strategy does not further increase the levels of circulating PCSK9 compared to rosuvastatin mono-intervention, thus maintaining maximal clinical benefits from lipid-lowering.

Nonstatin therapies for management of dyslipidemia: a review

PURPOSE

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in the United States. Recently published cholesterol treatment guidelines emphasize the use of statins as the preferred treatment strategy for both primary and secondary prevention of CVD. However, the optimal treatment strategy for patients who cannot tolerate statin therapy or those who need additional lipid-lowering therapy is unclear in light of recent evidence that demonstrates a lack of improved cardiovascular outcomes with combination therapy. The purpose of this review is to summarize and interpret evidence that evaluates nonstatin drug classes in reducing cardiovascular outcomes, to provide recommendations for use of nonstatin therapies in clinical practice, and to review emerging nonstatin therapies for management of dyslipidemia.

METHODS

Relevant articles were identified through searches of PubMed, International Pharmaceutical Abstracts, and the Cochrane Database of Systematic Reviews by using the terms niacin, omega-3 fatty acids (FAs), clofibrate, fibrate, fenofibrate, fenofibric acid, gemfibrozil, cholestyramine, colestipol, colesevelam, ezetimibe, proprotein convertase subtilisin/kexin 9 (PCSK9), cholesteryl ester transfer protein (CETP), and cardiovascular outcomes. Only English language, human clinical trials, meta-analyses, and systematic reviews were included. Additional references were identified from citations of published articles.

FINDINGS

Niacin may reduce cardiovascular events as monotherapy; however, recent trials in combination with statins have failed to show a benefit. Trials with omega-3 FAs have failed to demonstrate significant reductions in cardiovascular outcomes. Fibrates may improve cardiovascular outcomes as monotherapy; however, trials in combination with statins have failed to show a benefit, except in those with elevated triglycerides (>200 mg/dL) or low HDL-C (<40 mg/dL). There is a lack of data that evaluates bile acid sequestrant in combination with statin therapy on reducing cardiovascular events. Ezetimibe-statin combination therapy can reduce cardiovascular outcomes in those with chronic kidney disease and following vascular surgery or acute coronary syndrome. Long-term effects of emerging nonstatin therapies (CETP and PCSK9 inhibitors) are currently being evaluated in ongoing Phase III trials.

IMPLICATIONS

Nonstatin therapies have a limited role in reducing cardiovascular events in those maintained on guideline-directed statin therapy. In certain clinical situations, such as patients who are unable to tolerate statin therapy or recommended intensities of statin therapy, those with persistent severe elevations in triglycerides, or patients with high cardiovascular risk, some nonstatin therapies may be useful in reducing cardiovascular events. Future research is needed to evaluate the role of nonstatin therapies in those who are unable to tolerate guideline-directed statin doses.

Nonstatin Low-Density Lipoprotein-Lowering Therapy and Cardiovascular Risk Reduction-Statement From ATVB Council

Pharmacological reduction of low-density lipoprotein (LDL) cholesterol using statin drugs is foundational therapy to reduce cardiovascular disease (CVD) risk. Here, we consider the place of nonstatin therapies that also reduce LDL cholesterol in prevention of CVD. Among conventional nonstatins, placebo-controlled randomized clinical trials showed that bile acid sequestrants, niacin, and fibrates given as monotherapy each reduce CVD end points. From trials in which patients' LDL cholesterol was already well controlled on a statin, adding ezetimibe incrementally reduced CVD end points, whereas adding a fibrate or niacin showed no incremental benefit. Among emerging nonstatins, monoclonal antibodies against proprotein convertase subtilisin kexin type 9 added to a statin and given for ≤78 weeks showed preliminary evidence of reductions in CVD outcomes. Although these promising early findings contributed to the recent approval of these agents in Europe and in North America, much larger and longer duration outcomes studies are ongoing for definitive proof of CVD benefits. Other nonstatin agents recently approved in the United States include lomitapide and mipomersen, which both act via distinctive LDL receptor independent mechanisms to substantially reduce LDL cholesterol in homozygous familial hypercholesterolemia. We also address some unanswered questions, including measuring alternative biochemical variables to LDL cholesterol, evidence for treating children with monitoring of subclinical atherosclerosis, and potential risks of extremely low LDL cholesterol. As evidence for benefit in CVD prevention accumulates, we anticipate that clinical practice will shift toward more assertive LDL-lowering treatment, using both statins and nonstatins initiated earlier in appropriately selected patients.

Effect of Bile Acid Sequestrants on the Risk of Cardiovascular Events: A Mendelian Randomization Analysis

BACKGROUND

Statins lower low-density lipoprotein cholesterol (LDL-C) and risk of coronary artery disease (CAD), but they may be ineffective or not tolerated. Bile acid sequestrants (BAS) reduce LDL-C, yet their clinical efficacy on CAD remains controversial.

METHODS AND RESULTS

We conducted a systematic review and meta-analysis of randomized controlled trials to assess the effect of cholestyramine and colesevelam. We then used Mendelian randomization to estimate the effect of BAS on reducing the risk of CAD. First, we quantified the effect of rs4299376 (ABCG5/ABCG8), which affects the intestinal cholesterol absorption pathway targeted by BAS and then we used these estimates to predict the effect of BAS on CAD. Nineteen randomized controlled trials with a total of 7021 study participants were included. Cholestyramine 24 g/d was associated with a reduction in LDL-C of 23.5 mg/dL (95% confidence interval [CI] -26.8,-20.2; N=3806) and a trend toward reduced risk of CAD (odds ratio 0.81, 95% CI 0.70-1.02; P=0.07; N=3806), whereas colesevelam 3.75 g/d was associated with a reduction in LDL-C of 22.7 mg/dL (95% CI -28.3, -17.2; N=759). Based on the findings that rs4299376 was associated with a 2.75 mg/dL decrease in LDL-C and a 5% decrease in risk of CAD outcomes, we estimated that cholestyramine was associated with an odds ratio for CAD of 0.63 (95% CI 0.52-0.77; P=6.3×10(-6)) and colesevelam with an odds ratio of 0.64 (95% CI 0.52-0.79, P=4.3×10(-5)), which were not statistically different from BAS clinical trials (P>0.05).

CONCLUSIONS

The cholesterol lowering effect of BAS may translate into a clinically relevant reduction in CAD.

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.

Effects of lipid-lowering drugs on high-density lipoprotein subclasses in healthy men-a randomized trial

CONTEXT AND OBJECTIVE

Investigating the effects of lipid-lowering drugs on HDL subclasses has shown ambiguous results. This study assessed the effects of ezetimibe, simvastatin, and their combination on HDL subclass distribution.

DESIGN AND PARTICIPANTS

A single-center randomized parallel 3-group open-label study was performed in 72 healthy men free of cardiovascular disease with a baseline LDL-cholesterol of 111±30 mg/dl (2.9±0.8 mmol/l) and a baseline HDL-cholesterol of 64±15 mg/dl (1.7±0.4 mmol/l). They were treated with ezetimibe (10 mg/day, n = 24), simvastatin (40 mg/day, n = 24) or their combination (n = 24) for 14 days. Blood was drawn before and after the treatment period. HDL subclasses were determined using polyacrylamide gel-tube electrophoresis. Multivariate regression models were used to determine the influence of treatment and covariates on changes in HDL subclass composition.

RESULTS

Baseline HDL subclasses consisted of 33±10% large, 48±6% intermediate and 19±8% small HDL. After adjusting for baseline HDL subclass distribution, body mass index, LDL-C and the ratio triglycerides/HDL-C, there was a significant increase in large HDL by about 3.9 percentage points (P<0.05) and a decrease in intermediate HDL by about 3.5 percentage points (P<0.01) in both simvastatin-containing treatment arms in comparison to ezetimibe. The parameters obtained after additional adjustment for the decrease in LDL-C indicated that about one third to one half of these effects could be explained by the extent of LDL-C-lowering.

CONCLUSIONS

In healthy men, treatment with simvastatin leads to favorable effects on HDL subclass composition, which was not be observed with ezetimibe. Part of these differential effects may be due to the stronger LDL-C-lowering effects of simvastatin.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00317993.

The severe hypercholesterolemia phenotype: clinical diagnosis, management, and emerging therapies

The severe hypercholesterolemia phenotype includes all patients with marked elevation of low-density lipoprotein cholesterol (LDL-C) levels. The most common cause is autosomal dominant hypercholesterolemia, an inherited disorder caused by mutations either in LDL receptor, apolipoprotein B (APOB), or proprotein convertase subtilisin kexin type 9 (PCSK9) genes. However, it is now known that many subjects with severe inherited hypercholesterolemia have no defects in these genes. These cases are caused either by mutations in genes yet to be identified or are consequences of polygenic, epigenetic, or acquired defects. Because the clinical consequences of extreme hypercholesterolemia are the same no matter the cause, the focus should be on the identification of subjects with severe hypercholesterolemia, followed by phenotypic screening of family members. Genetic screening is not necessary to diagnose or initiate treatment for the severe hypercholesterolemia phenotype. Management of severe hypercholesterolemia is based on risk factor modification and use of multiple lipid-lowering medications. Lipoprotein apheresis is indicated for coronary artery disease (CAD) patients taking maximally tolerated therapy and with LDL-C levels >200 mg/dl (>300 mg/dl if without CAD). A microsomal triglyceride transfer protein inhibitor and an antisense oligonucleotide against APOB have recently been approved for use in subjects with clinically diagnosed homozygous familial hypercholesterolemia. PCSK9 inhibitors, currently in phase II and III trials, lower LDL-C up to an additional 70% in the setting of maximally tolerated medical therapy and have the potential to reduce LDL-C to <70 mg/dl in most patients. Early identification of affected individuals and aggressive treatment should significantly reduce the burden of cardiovascular disease in society.

Colesevelam hydrochloride in the management of dyslipidemia

Dyslipidemia is a highly heterogeneous group of disorders strongly influenced by both genetic and environmental factors. Dyslipidemia significantly increases risk for atherosclerotic disease and all of its various clinical manifestations. Identifying patients with dyslipidemia and initiating therapies aimed at normalizing the lipid profile has been demonstrated to significantly reduce the risk for myocardial infarction, stroke and cardiovascular mortality in both the primary and secondary prevention settings. Guidelines in Europe, Canada and the USA emphasize the need to reduce the burden of atherogenic lipoproteins in serum and to raise levels of high-density lipoproteins in patients at risk for cardiovascular events. Statins have emerged as front-line therapy for managing dyslipidemia, especially in patients with elevated serum levels of low-density lipoprotein cholesterol. As guidelines emphasize the need to reduce serum low-density lipoprotein cholesterol to lower levels, goal attainment can be challenging. The use of combination therapy increases the likelihood of therapeutic success for many patients. Furthermore, a significant percentage of patients with dyslipidemia either cannot achieve goals on statin monotherapy, choose not to take a statin or do not tolerate these drugs due to adverse side effects, such as myalgias, weakness or hepatotoxicity. This article summarizes the pharmacology, clinical efficacy and safety of colesevelam hydrochloride, a bile acid-binding resin. Bile acid-binding resins are orally administered anion-exchange resins that are not absorbed systemically. These agents bind bile acids and reduce their reabsorption at the level of the terminal ileum and prevent their enterohepatic recirculation. Colesevelam has a favorable side effect and toxicity profile and significantly impacts serum levels of lipoproteins when used as monotherapy or when used in combination with either statins or ezetimibe.

Combination therapy with ezetimibe and simvastatin to achieve aggressive LDL reduction

A low-density lipoprotein (LDL) cholesterol goal of less than 100 mg/dl is recommended for patients at moderate to high risk of cardiovascular disease with an optional LDL goal of less than 70 mg/dl for patients at a very high risk of cardiovascular disease. Most patients will require reductions in LDL of more than 50% in order to achieve these more aggressive goals. Only a few agents will lower LDL by at least 50%. This review will focus on the efficacy and safety ezetimibe/simvastatin coadministered as a therapy with enhanced LDL-lowering efficacy, while minimizing the adverse effects of statins in a wide range of patients. Ezetimibe 10 mg/simvastatin 80 mg lowers LDL by approximately 60% and has been demonstrated to be superior to the highest doses of atorvastatin and rosuvastatin for lowering LDL and raising high-density lipoprotein.

Colesevelam in the treatment of hypercholesterolemia and hyperglycemia: a retrospective analysis from an ambulatory care medical network

OBJECTIVE

To examine outcomes associated with colesevelam treatment among patients with hypercholesterolemia in real-world clinical practice.

METHODS

This analysis was conducted as a retrospective, observational cohort study in an ambulatory-care medical network in Northern California. Patients with orders for colesevelam were identified in the electronic health record between January 2004 and December 2011. The date of the first order during the study period was designated the index date. Patients were evaluated for the following eligibility criteria: a diagnosis of hypercholesterolemia, ≥18 years of age at index date, baseline laboratory values ≤3 months before the index date, ≥12 months of treatment and follow-up, and no prior orders for colesevelam ≤12 months before the index date. Patients who were pregnant during the study period were excluded. Changes in LDL-C and percentage of patients at LDL-C goal were examined. Among patients with diabetes mellitus (DM), changes in glycated hemoglobin (HBA1C) and percentage of patients at HBA1C goal were also examined.

RESULTS

Overall, 468 and 181 patients with hypercholesterolemia met the predefined inclusion criteria with treatment and follow-up through 12 and 24 months, respectively. LDL-C decreased significantly from baseline by a mean of 11.4 mg/dL and 15.7 mg/dL (P < 0.0001, for each) at 12 and 24 months, respectively, and the percentages of patients at LDL-C goal increased by 13.9% and 21.0%. Among patients with DM and a baseline HBA1C ≥8%, 113 and 39 had treatment and follow-up through 12 and 24 months, respectively. HBA1C decreased significantly by a mean of 0.72% (P = 0.0001) and 0.75% (P = 0.010) and 11.5% and 12.8% were at HBA1C goal at 12 and 24 months, respectively. This study is limited by its retrospective and observational study design.

CONCLUSIONS

Colesevelam treatment in a real-world setting was associated with improvements in LDL-C and HBA1C through 24 months of follow-up.

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.

Dyslipidemia in patients with chronic and end-stage kidney disease

In this review, we discuss the physiology, diagnosis and treatment of dyslipidemia in patients with chronic and end-stage renal disease. The recent important clinical trials in patients with chronic kidney disease and dyslipidemia are reviewed. Because of the lack of evidence in treating lipid abnormalities in this specific patient population, we propose that future studies should focus on the pathophysiological mechanisms and treatment of dyslipidemia in this special patient population.

Ezetimibe and bile acid sequestrants: impact on lipoprotein metabolism and beyond

PURPOSE OF REVIEW

Several lines of evidence indicate that the enterocyte plays a pivotal role in cholesterol homeostasis. The development of the selective inhibitor of cholesterol absorption ezetimibe and bile acid sequestrants (BAS) interrupting the enterohepatic circulation of bile salts has expanded the options for preventing and treating cardiovascular disease. We discuss here a selection of recently published studies that evaluated the effects of ezetimibe and BAS on lipoprotein metabolism.

RECENT FINDINGS

Although significant progress has been made in recent years in elucidating the impacts of ezetimibe and BAS on lipoprotein metabolism, underlying mechanisms are not completely understood. Important new insights have been provided by using in-vivo kinetic studies of apolipoproteins labelled with a stable isotope. Other reports indicated that ezetimibe and BAS modulate the expression of several key genes involved in intestinal lipoprotein metabolism. Many of these effects have been related to the local effects of ezetimibe and BAS on intestinal cholesterol homeostasis.

SUMMARY

A substantial effort is being made by researchers to fully understand the mechanisms by which ezetimibe and BAS improve lipid profile. The efficacy of combination therapy of statins with ezetimibe or BAS for the prevention of cardiovascular disease remains to be confirmed in clinical endpoint studies.

Evidence from a randomized trial that simvastatin, but not ezetimibe, upregulates circulating PCSK9 levels

Background

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a secreted inhibitor of the low-density lipoprotein (LDL) receptor and an important regulator of LDL metabolism. Elevated PCSK9 levels have been associated with cardiovascular risk. The purpose of this study was to investigate how ezetimibe and simvastatin, alone and in combination, affect PCSK9 circulating concentrations.

Methods

A single center, randomized, open-label parallel 3-group study in healthy men (mean age 32±9 years, body mass index 25.7±3.2 kg/m²) was performed. Each group of 24 subjects was treated for 14 days with either simvastatin 40 mg/d, ezetimibe 10 mg/d, or with both drugs. Multivariate analysis was used to investigate parameters influencing the change in PCSK9 concentrations under treatment.

Results

The baseline plasma PCSK9 concentrations in the total cohort were 52±20 ng/mL with no statistically significant differences between the groups. They were increased by 68±85% by simvastatin (P = 0.0014), by 10±38% by ezetimibe (P = 0.51) and by 67±91% by simvastatin plus ezetimibe (P = 0.0013). The increase in PCSK9 was inversely correlated with baseline PCSK9 concentrations (Spearman’s R = –0.47, P<0.0001) and with the percent change in LDL cholesterol concentrations (Spearman’s R = –0.30, P<0.01). In multivariate analyses, only baseline PCSK9 concentrations (β = –1.68, t = –4.04, P<0.0001), percent change in LDL cholesterol from baseline (β = 1.94, t = 2.52, P = 0.014), and treatment with simvastatin (P = 0.016), but not ezetimibe (P = 0.42), significantly influenced changes in PCSK9 levels. Parameters without effect on PCSK9 concentration changes were age, body mass index, body composition, thyroid function, kidney function, glucose metabolism parameters, adipokines, markers of cholesterol synthesis and absorption, and molecular markers of cholesterol metabolism.

Conclusions

Ezetimibe does not increase circulating PCSK9 concentrations while simvastatin does. When added to simvastatin, ezetimibe does not cause an incremental increase in PCSK9 concentrations. Changes in PCSK9 concentrations are tightly regulated and mainly influenced by baseline PCSK9 levels and changes in LDL cholesterol.

Trial Registration

ClinicalTrials.gov NCT00317993

Established and emerging approaches for the management of dyslipidaemia

The key role of dyslipidaemia in determining cardiovascular disease (CVD) has been proved beyond reasonable doubt, and therefore several dietary and pharmacological approaches have been developed. The discovery of statins has provided a very effective approach in reducing cardiovascular risk as documented by the results obtained in clinical trials and in clinical practice. The current efficacy of statins or other drugs, however, comes short of providing the benefit that could derive from a further reduction of LDL cholesterol (LDL-C) in high-risk and very high risk patients. Furthermore, experimental data clearly suggest that other lipoprotein classes beyond LDL play important roles in determining cardiovascular risk. For these reasons a number of new potential drugs are under development in this area. Aim of this review is to discuss the available and the future pharmacological strategies for the management of dyslipidemia.

Is combination therapy an effective way of reaching lipid goals in type 2 diabetes mellitus?

Type 2 diabetes mellitus is associated with a specific pattern of plasma lipid and lipoprotein abnormalities. Lipid goals are often not attained with statins alone, and combination lipid-lowering strategies may need to be considered in an attempt to further reduce the residual cardiovascular risk. Combination therapy utilizes various classes of lipid-lowering medications with different mechanisms of action and different effects on lipid levels. Clinical trial data support the efficacy of combining statins with fibrates, niacin, ezetimibe (cholesterol absorption inhibitor) and colesevelam (bile acid sequestrant) with the caveat that there are insufficient clinical trial data to show a further robust benefit on cardiovascular outcomes. Of the different combination therapy options to potentiate low-density lipoprotein cholesterol lowering in combination with a statin, colesevelam provides additional beneficial effects by further reducing hemoglobin A1c levels in Type 2 diabetes mellitus.

Glucose and low-density lipoprotein cholesterol lowering in elderly patients with type 2 diabetes: focus on combination therapy with colesevelam HCl

The prevalence of type 2 diabetes mellitus is high among the elderly population. Treatment of elderly patients with type 2 diabetes presents challenges because of co-morbidities and the potential increase in the risk of adverse effects. Hyperlipidaemia is also common in the elderly population. Glucose-and lipid-lowering treatment in elderly patients should be individualized on the basis of the patient’s life expectancy, health status and cardiovascular risk factors, and evidence-based guideline recommendations. Because elderly patients often have impaired renal and hepatic function, careful considerations must be made when selecting appropriate glucose- and lipid-lowering therapy. There are a number of potential safety issues associated with various glucose- and lipid-lowering therapies that are relevant to elderly patients, including increased risk of heart failure exacerbations, weight loss, increased risk of hypoglycaemia, increased risk of myopathy, and contraindications of some agents in patients with hepatic or renal impairment. The bile acid sequestrant colesevelam HCl is unique compared with other glucose- and lipid-lowering therapies because it is the only product approved by the US Food and Drug Administration, as an adjunct to diet and exercise, to lower both glucose and low-density lipoprotein cholesterol (LDL-C) in adults with type 2 diabetes and primary hyperlipidaemia, respectively. Furthermore, colesevelam has been shown to have similar glucose- and lipid-lowering efficacy in patients aged <65 years and those aged ≥65 years. Colesevelam was not associated with weight gain, was associated with a low incidence of hypoglycaemia, and can be safely combined with a broad range of glucose-lowering agents (metformin, sulfonylureas and insulin) and lipid-lowering statins. Currently, colesevelam is available in tablet form and as a powder for oral suspension formulation; the latter may be of benefit to elderly patients with swallowing difficulties. As colesevelam has both glucose- and lipid-lowering effects, its use may reduce the drug burden in elderly patients receiving multiple agents for glucose and lipid lowering. Colesevelam may be a valuable treatment option as an add-on to existing glucose- and/or lipid-lowering therapy to help improve haemoglobin A_1c and to lower LDL-C levels in elderly patients with type 2 diabetes and primary hyperlipidaemia.

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.

Management of patients with type 2 diabetes

BACKGROUND

The number of treatment options in the diabetes arena has grown dramatically in a short period of time, with a corresponding increase in the breadth and depth of literature from which physicians and diabetes organizations make evidence-based decisions. Thus, the purpose of this article is to provide an up-to-date review of the literature describing current treatment options and guidelines available for the management of type 2 diabetes and prevention of its complications.

METHODS

Pubmed searches were conducted for recent literature pertaining to the prevention of complications in type 2 diabetes. Comprehensive search terms were devised to identify articles describing micro- and macrovascular complications including nephropathy, neuropathy, retinopathy, and cardiovascular disease associated with type 2 diabetes.

CONCLUSIONS

The current body of literature demonstrates that a significant reduction in the incidence of diabetic complications is achievable with early initiation and long-term maintenance of controlled blood glucose and cardiovascular risk factors. Screening for diabetic complications should be initiated early and continued at regular intervals to ensure early pharmacological intervention.

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 bile acid sequestrants in the management of type 2 diabetes mellitus

The prevalence of type 2 diabetes (T2DM) and cardiovascular disease (CVD) continues to escalate globally. There is now abundant clinical trial evidence that the optimal treatment of CVD risk factors, with lifestyle changes aimed at weight loss in most patients, and pharmacologic management of dyslipidemia and hyperglycemia, can help mitigate the CVD burden. Yet more than 50% of patients are still not achieving glycosylated hemoglobin (HbA1c) and low-density lipoprotein cholesterol (LDL-C) goals. Over the past 15 years, many novel and emerging drugs have made it possible to achieve optimal glycemic control, generally in combination therapy, without untoward effects of weight gain, hypoglycemia, and other adverse effects with traditional agents. Although the long-term efficacy and safety of some of the newer classes of agents are yet to be determined, bile acid sequestrants represent a unique long-standing class of agents. These drugs have the dual efficacy in glycemic control and LDL-C reduction, and an established record of long-term safety. Colesevelam HCl is the only drug approved for this dual indication and is an adjunct in the treatment of both hyperglycemia and hypercholesterolemia that frequently co-exist in adults with T2DM.

Drug treatment of hyperlipidaemia: a guide to the rational use of lipid-lowering drugs

Mammalian sterol and lipid metabolism depends on a large number of highly evolved biochemical and histological processes responsible for the absorption, distribution and steady-state anabolic/catabolic handling of these substances. Lipoproteins are complex polymolecular assemblies comprising phospholipids, cholesterol and cholesterol esters, triglycerides and a variety of apolipoproteins. The primary function of lipoproteins is to facilitate the systemic distribution of sterols and lipids. Abnormalities in lipoprotein metabolism are quite common and are attributable to a large number of genetic mutations, metabolic derangements such as insulin resistance or thyroid dysfunction, and excess availability of cholesterol and fat from dietary sources. Dyslipidaemic states facilitate endothelial dysfunction and atherogenesis. Dyslipidaemia is recognized as a risk factor for cardiovascular disease in both men and women, and people of all racial and ethnic groups throughout the world. Dyslipidaemia is modifiable with dietary change and the use of medications that impact on lipid metabolism through a variety of mechanisms. Reducing atherogenic lipoprotein burden in serum is associated with significant and meaningful reductions in risk for a variety of cardiovascular endpoints, including myocardial infarction, ischaemic stroke, development of peripheral arterial disease and mortality. This review provides an overview on how to best position lipid-lowering drugs when attempting to normalize serum lipid profiles and reduce risk for cardiovascular disease. HMG-CoA reductase inhibitors (statins) are widely accepted to be the agents of choice for reducing serum levels of low-density lipoprotein cholesterol (LDL-C) in both the primary and secondary prevention settings. Ezetimibe and bile acid sequestrants are both effective agents for reducing LDL-C, either used alone or in combination with statins. The statins, fibric acid derivatives (fibrates) and niacin raise high-density lipoprotein cholesterol to different extents depending upon genetic and metabolic background. Fibrates, niacin and omega-3 fish oils are efficacious therapies for reducing serum triglycerides. Combinations of these drugs are frequently required for normalizing mixed forms of dyslipidaemia.