The oral adenosine triphosphate-citrate lyase (ACL) inhibitor bempedoic acid was approved by the FDA in 2020 for use alone (Nexletol – Esperion) and in a fixed-dose combination with the cholesterol absorption inhibitor ezetimibe (Nexlizet) as an adjunct to maximally tolerated statin therapy in adults with heterozygous familial hypercholesterolemia (HeFH) or established atherosclerotic cardiovascular disease (ASCVD) who require additional LDL-cholesterol (LDL-C) lowering. The indication has now been expanded to include reducing the risk of myocardial infarction (MI) and coronary revascularization in adults with established cardiovascular disease (CVD) or at high risk for a CVD event who are unable to take recommended statin therapy.

Since our initial review of the oral lipid-lowering adenosine triphosphate-citrate lyase (ACL) inhibitor bempedoic acid (Nexletol – Esperion) in 2020, cardiovascular outcomes data in statin-intolerant patients have become available.

View the Comparison Table: Some Lipid-Lowering Drugs

The FDA has approved inclisiran (Leqvio – Novartis), a small interfering RNA (siRNA) directed to proprotein convertase subtilisin/kexin type 9 (PCSK9) mRNA, as an adjunct to diet and maximally tolerated statin therapy for subcutaneous (SC) treatment of adults with heterozygous familial hypercholesterolemia (HeFH) or clinical atherosclerotic cardiovascular disease (ASCVD) who require additional lowering of low-density lipoprotein cholesterol (LDL-C). Inclisiran is the first FDA-approved PCSK9-directed siRNA therapeutic agent.

The FDA has approved evinacumab-dgnb (Evkeeza – Regeneron), an angiopoietin-like 3 (ANGPTL3) inhibitor, for adjunctive IV treatment of homozygous familial hypercholesterolemia (HoFH) in patients ≥12 years old. Evinacumab is the first ANGPTL3 inhibitor to be approved in the US.

The FDA has approved the oral adenosine triphosphate-citrate lyase (ACL) inhibitor bempedoic acid for use alone (Nexletol – Esperion) and in a fixed-dose combination with the cholesterol absorption inhibitor ezetimibe (Nexlizet) as an adjunct to diet and maximally tolerated statin therapy in adults with heterozygous familial hypercholesterolemia (HeFH) or established atherosclerotic cardiovascular disease (ASCVD) who require additional lowering of LDL-cholesterol (LDL-C). Bempedoic acid is the first ACL inhibitor to be approved in the US.

Cholesterol management guidelines from the American College of Cardiology/American Heart Association Task Force have recently been published. See Table 1 for a brief summary of their recommendations.

View the Expanded Table: Lipid-Lowering Drugs

The results of the recently published FOURIER trial have shown a reduction in cardiovascular events with addition of the PCSK9 inhibitor evolocumab (Repatha) to statin therapy in patients with atherosclerotic cardiovascular disease (ASCVD).

Lipid-lowering drugs should be taken indefinitely; when they are stopped, plasma lipoproteins return to pretreatment levels. HMG-CoA reductase inhibitors (statins) remain the drugs of choice for treatment of most patients who require lipid-lowering therapy.

The FDA has approved the subcutaneously injected PCSK9 (proprotein convertase subtilisin kexin type 9) inhibitor alirocumab (Praluent – Sanofi/Regeneron) as an adjunct to diet and maximally tolerated statin therapy for adults with heterozygous familial hypercholesterolemia (HeFH) or clinical atherosclerotic cardiovascular disease who require additional lowering of LDL-cholesterol (LDL-C). It was not approved for general use in statin-intolerant patients. Alirocumab is the first PCSK9 inhibitor to be approved in the US. Evolocumab (Repatha – Amgen), another PCSK9 inhibitor, was recently approved in Europe and has been recommended for approval for the same indications in the US by an FDA Advisory Committee.

Combining a statin with another drug that lowers low-density lipoprotein cholesterol (LDL-C), such as colesevelam (Welchol), niacin (Niaspan, and others), or ezetimibe (Zetia), can reduce LDL-C levels more than a statin alone, but studies convincingly demonstrating that such combinations improve clinical outcomes have been lacking. The results of a long-term randomized, double-blind clinical trial (IMPROVE-IT) recently presented at the American Heart Association's Scientific Sessions 2014 indicate that addition of ezetimibe to simvastatin in high-risk patients reduces cardiovascular events.1

IMPROVE-IT compared the efficacy of simvastatin 40 mg plus placebo with that of simvastatin 40 mg plus ezetimibe 10 mg (Vytorin) in preventing the primary endpoint, a composite of cardiovascular events (cardiovascular death, MI, hospital admission for unstable angina, coronary revascularization, or stroke) in patients with acute coronary syndrome and normal LDL-C levels (≤125 mg/dL; mean 95 mg/dL). After one year, mean LDL-C was reduced further with the addition of ezetimibe (to 53.2 vs. 69.9 mg/dL with simvastatin alone). After 7 years, 2742 events had occurred among the 9077 patients taking simvastatin plus placebo and 2572 among the 9067 taking simvastatin plus ezetimibe (event rate: 34.7% vs. 32.7%; p = 0.016). There was no significant difference between the 2 groups in noncardiovascular adverse events, including gallbladder-related events, myopathy, or cancer.

1. C Cannon et al. IMProved Reduction of Outcomes: Vytorin Efficacy International Trial. Available at www.timi.org. Accessed November 21, 2014.

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HMG-CoA reductase inhibitors (statins) inhibit the enzyme that catalyzes the rate-limiting step in cholesterol synthesis. The subsequent reduction in hepatic cholesterol leads to increased expression of LDL receptors, which in turn increases uptake and clearance of LDL-C from the blood. Statins also lower very low-density lipoprotein cholesterol (VLDL-C) and triglycerides. Most statins increase high-density lipoprotein cholesterol (HDL-C), but only modestly.

The FDA has approved a fixed-dose combination of the cholesterol absorption inhibitor ezetimibe and the HMG-CoA reductase inhibitor (statin) atorvastatin as Liptruzet (Merck) for treatment of hyperlipidemia. Ezetimibe is also available in a fixed-dose combination with simvastatin (Vytorin).

The FDA has approved mipomersen (Kynamro – Genzyme) and lomitapide (Juxtapid – Aegerion), each in addition to a low-fat diet and other lipid-lowering medications, to reduce cholesterol levels in patients with homozygous familial hypercholesterolemia (HoFH).

Drugs that lower low-density lipoprotein cholesterol (LDL-C) concentrations can prevent formation, slow progression and cause regression of atherosclerotic lesions. Lipid-regulating drugs must be taken indefinitely; when they are stopped, plasma lipoproteins return to pretreatment levels in 2-3 weeks.

Readers have asked us to update our 2004 article on tablet splitting. Breaking drug tablets in half is a common practice, but the FDA recently advised consumers against it (FDA Consumer Health Information, July 2009).

The National Cholesterol Education Program recommends that LDL-C be lowered to less than 100 mg/dL (2.6 mmol/L) and considers a value <70 mg/dL (1.8 mmol/L) a reasonable goal for patients at very high risk.

In recent months, both the lay media and some medical experts have raised concerns about the effectiveness and safety of ezetimibe, a widely used drug that prevents absorption of cholesterol from the GI tract. Ezetimibe is available alone as Zetia and in combination with 10, 20, 40 and 80 mg of simvastatin (Zocor, and others) as Vytorin.

Drugs that lower low-density lipoprotein cholesterol (LDL-C) concentrations can prevent formation, slow progression and cause regression of atherosclerotic lesions. They should not be used as a substitute for lifestyle changes; a combination of diet, exercise and lipid-lowering drugs is optimal for prevention of coronary disease. Lipid-regulating drugs must be taken indefinitely; when they are stopped, plasma lipoprotein levels return to pretreatment levels in 2-3 weeks.

An unpublished 2-year randomized study (ENHANCE) on the effect of adding ezetimibe 10 mg to simvastatin 80 mg in 720 patients with heterozygous familial hypercholesterolemia has been in the news recently. About 80% of these patients had previously been treated with statins. The primary endpoint was the change in the intima-media thickness (IMT) of the carotid artery (baseline 0.68 and 0.69 mm); the IMT increased by 0.0111 mm with ezetimibe plus simvastatin and 0.0058 mm with simvastatin 80 mg alone (p=0.29). The ezetimibe- simvastatin combination lowered LDL-C by 58% compared to 41% lowering with simvastatin alone (p<0.01). The study was not powered to assess cardiovascular events; cardiovascular deaths occurred in 2 patients treated with both drugs and 1 on simvastatin alone.

Ezetimibe, an inhibitor of cholesterol absorption, is available both alone (Zetia) and in combination with 10, 20, 40 and 80 mg of simvastatin (Vytorin). No data have been published on the effect of ezetimibe on cardiovascular events with or without simvastatin. Whether addition of ezetimibe to a statin is as effective as raising the dose of the statin in decreasing the number of cardiovascular events remains to be determined in larger studies that are underway.

Neither Zetia or Vytorin is recommended for initial treatment of hypercholesterolemia.

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Drugs that lower low-density lipoprotein cholesterol (LDL-C) concentrations can prevent formation, slow progression and cause regression of atherosclerotic lesions. In controlled trials in patients with coronary disease, some of these drugs have reduced mortality by 20% to 30%.

Health Canada, the Canadian equivalent of the FDA, recently issued a public advisory about postmarketing reports of myalgia, rhabdomyolysis, hepatitis, pancreatitis and thrombocytopenia associated with use of ezetimibe (Zetia in the US; Ezetrol in Canada). Ezetimibe is often added to a statin to increase LDL cholesterol lowering (Drugs for Lipids, Treat Guidel Med Lett 2005; 3:15). The advisory did not specify whether these patients were also taking a statin, but according to the Canadian manufacturer Merck Frosst/Schering (Merck/Schering-Plough in the US), some of the patients who developed rhabdomyolysis were taking ezetimibe without a statin. In the US, ezetimibe is also available in a combination with simvastatin (Vytorin - Med Lett Drugs Ther 2004; 46:73). Recently, a few patients already taking a statin developed myalgia when ezetimibe was added (R Fux et al, Ann Intern Med 2004; 140:671). The possibility that adding ezetimibe to a statin could increase the risk of rhabdomyolysis should be kept in mind.

Vytorin, a fixed-dose combination of the cholesterol absorption inhibitor ezetimibe (Zetia - Merck/Schering Plough) and the HMG-CoA reductase inhibitor ("statin") simvastatin (Zocor - Merck), has been approved by the FDA for treatment of hypercholesterolemia. It is available as tablets containing 10 mg of ezetimibe combined with 10, 20, 40 or 80 mg of simvastatin.

The recent "PROVE IT" trial in patients with coronary heart disease showed clinical benefits associated with reducing LDL cholesterol concentrations lower than the 100 mg/dL (2.59 mmol/L) or less that had been considered optimal.

Drugs that lower low-density lipoprotein (LDL) cholesterol concentrations can prevent formation, slow progression and cause regression of atherosclerotic lesions, and also improve vasodilatation. In controlled trials in patients with coronary disease, they have reduced mortality by 30% to 40%. Lipid-regulating drugs must be taken indefinitely; when they are stopped, plasma lipid levels return to pretreatment levels in 2-3 weeks.

The FDA recently approved three new drugs for treatment of hyperlipidemia. Ezetimibe (ez et' i mibe; Zetia) is the first in a new class of drugs that inhibit intestinal absorption of cholesterol. Extended-release lovastatin (Altocor) is a new formulation of lovastatin (Mevacor, and others). Extended-release niacin plus (immediate-release) lovastatin (Advicor) is the first fixed-dose combination of lipid-lowering drugs.