Pharmacokinetic Interactions of the Microsomal Triglyceride Transfer Protein Inhibitor, Lomitapide, with Drugs Commonly Used in the Management of Hypercholesterolemia

Research Progress in the Clinical Treatment of Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is an autosomal dominant inheritable disease with severe disorders of lipid metabolism. It is mainly marked by increasing levels of plasma total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C), xanthoma, corneal arch, and early-onset coronary heart disease (CHD). The prevalence of FH is high, and it is dangerous and clinically underdiagnosed. The clinical treatment for FH includes both pharmacological and non-pharmacological treatment, of which non-pharmacological treatment mainly includes therapeutic lifestyle change and dietary therapy, LDL apheresis, liver transplantation and gene therapy. In recent years, many novel drugs have been developed to treat FH more effectively. In addition, the continuous maturity of non-pharmacological treatment techniques has also brought more hope for the treatment of FH. This paper analyzes the pathogenic mechanism and the progress in clinical treatment of FH. Furthermore, it also summarizes the mechanism and structure-activity relationship of FH therapeutic drugs that have been marketed. In a word, this article provides a reference value for the research and development of FH therapeutic drugs.

A quantitative systems pharmacology modeling platform for evaluating triglyceride profiles in patients with high triglycerides receiving evinacumab

A model to quantitatively characterize the effect of evinacumab, an investigational monoclonal antibody against angiopoietin‐like protein 3 (ANGPTL3) on lipid trafficking is needed. A quantitative systems pharmacology (QSP) approach was developed to predict the transient responses of different triglyceride (TG)‐rich lipoprotein particles in response to evinacumab administration. A previously published hepatic lipid model was modified to address specific queries relevant to the mechanism of evinacumab and its effect on lipid metabolism. Modifications included the addition of intermediate‐density lipoprotein and low‐density lipoprotein compartments to address the modulation of lipoprotein lipase (LPL) activity by evinacumab, ANGPTL3 biosynthesis and clearance, and a target‐mediated drug disposition model. A sensitivity analysis guided the creation of virtual patients (VPs). The drug‐free QSP model was found to agree well with clinical data published with the initial hepatic liver model over simulations ranging from 20 to 365 days in duration. The QSP model, including the interaction between LPL and ANGPTL3, was validated against clinical data for total evinacumab, total ANGPTL3, and TG concentrations as well as inhibition of apolipoprotein CIII. Free ANGPTL3 concentration and LPL activity were also modeled. In total, seven VPs were created; the lipid levels of the VPs were found to match the range of responses observed in evinacumab clinical trial data. The QSP model results agreed with clinical data for various subjects and was shown to characterize known TG physiology and drug effects in a range of patient populations with varying levels of TGs, enabling hypothesis testing of evinacumab effects on lipid metabolism.

Abrogation of postprandial triglyceridemia with dual PPAR α/γ agonist in type 2 diabetes mellitus: a randomized, placebo-controlled study

AIMS

Lowering postprandial lipemia may mitigate cardiovascular risk in patients with diabetic dyslipidemia. This study was aimed to investigate whether saroglitazar suppresses postprandial lipemia in patients with diabetes and dyslipidemia.

METHODS

This was a 12-week, prospective, multicenter, randomized, double-blinded, placebo-controlled study of saroglitazar in patients with diabetes and dyslipidemia. Thirty patients were randomized (1:1) to receive saroglitazar 4 mg or placebo orally once daily with metformin for 12 weeks. The primary endpoint was change in plasma triglyceride (TG) area under the curve (AUC) on a standardized 8-h fat tolerance test.

RESULTS

Thirty participants were randomized for interventions and eventually data of 19 participants qualified for per protocol analyses. Mean (SD) age in saroglitazar was 53.1 (8.8) years and 54.9 (7.7) years in placebo group. After 12 weeks, saroglitazar significantly lowered postprandial TG-AUC by - 458.3 (144.0) (- 25.7%, 95% CI - 765.1 to - 151.4) versus an increase of + 10.9 (157.9) (+ 0.5%, 95% CI - 325.6 to 347.3) mg/dL h in placebo group (P < 0.05). Saroglitazar lowered postprandial TG incremental AUC versus placebo: - 329.4 (89.9) (- 59%) versus + 80.4 (99.4) (+ 10%) mg/dL h (P < 0.05). HbA1c (%) decreased by - 0.36 (0.42) in the saroglitazar group as compared to an increase of + 1.26 (0.46) (P < 0.05) with placebo.

CONCLUSIONS

The saroglitazar treatment significantly improved postprandial TGs in people with diabetic dyslipidemia.

TRIAL REGISTRATION

Clinical Trial Registry of India; trial Registration No.: CTRI/2015/06/005845 and Date of registration: June 02, 2015.

Experimental Therapeutics for Challenging Clinical Care of a Patient with an Extremely Rare Homozygous APOC2 Mutation

Background

Among many causes of hypertriglyceridemia (HTG), familial chylomicronemia syndrome (FCS) is a rare monogenic disorder that manifests as severe HTG and acute pancreatitis. Among the known causal genes for FCS, mutations in APOC2 only account for <2% of cases. Medical nutrition therapy is critical for FCS because usual triglyceride- (TG-) lowering medications are ineffective. Therapeutic plasma exchange (TPE) with fresh frozen plasma (FFP) is an option to urgently reduce TG and pancreatitis episodes. Several novel biologics are under development to treat HTG and may provide therapeutic options for FCS in the future.

Objective

We present the challenging care of a 43-year-old man with FCS with apoC-II deficiency and the results of two types of TPE and of investigational TG-lowering biologic therapies.

Results

The patient's lipid profile was consistent with FCS. A novel homozygous variant was identified in APOC2, and its pathogenicity was confirmed. Even on a fat-restricted diet, his care was tremendously complicated with unremitting bouts of pancreatitis. TPE with FFP replacement lowered TG >90% post-sessions and appeared to reduce pancreatitis episodes. Experimental ANGPTL3 and APOC3 inhibitors each lowered TG by >50%.

Conclusions

Our case demonstrates the importance of delineating and defining the underlying etiology of a rare disorder to optimize therapy and to minimize unfavorable outcomes.

LDL-Cholesterol-Lowering Therapy

The causal relation between elevated levels of LDL-C and cardiovascular disease has been largely established by experimental and clinical studies. Thus, the reduction of LDL-C levels is a major target for the prevention of cardiovascular disease. In the last decades, statins have been used as the main therapeutic approach to lower plasma cholesterol levels; however, the presence of residual lipid-related cardiovascular risk despite maximal statin therapy raised the need to develop additional lipid-lowering drugs to be used in combination with or in alternative to statins in patients intolerant to the treatment. Several new drugs have been approved which have mechanisms of action different from statins or impact on different lipoprotein classes.

Familial hypercholesterolemia treatments: Guidelines and new therapies

Familial hypercholesterolemia (FH) is a genetic disorder resulting from mutations in genes encoding proteins involved in the metabolism of low density lipoproteins (LDL) and characterized by premature cardiovascular disease due to the exposure to high levels of LDL-cholesterol (LDL-C) from birth. Thus, the early identification of FH subjects, followed by appropriate treatment is essential to prevent or at least delay the onset of cardiovascular events. However, FH is largely underdiagnosed; in addition, FH patients are frequently not adequately treated, despite the availability of several pharmacological therapies to significantly reduce LDL-C levels. Current guidelines recommend LDL-C targets for FH (either heterozygotes [HeFH] or homozygotes [HoFH]) <100 mg/dL (<2.6 mmol/L) for adults or <70 mg/dL (<1.8 mmol/L) for adults with CHD or diabetes, and <135 mg/dL (<3.5 mmol/L) for children. With the pharmacological options now available, which include statins as a first approach, ezetimibe, and the recently approved monoclonal antibodies targeting PCSK9, the guideline recommended LDL-C target levels can be achieved in the majority of heterozygous FH subjects, while for the most severe forms of homozygous FH, the addition of therapies such as lomitapide either with or without apheresis may be required.

Lomitapide: a review of its clinical use, efficacy, and tolerability

Lomitapide is an inhibitor of MTP, an enzyme located in the endoplasmic reticulum of hepatocytes and enterocytes. This enzyme is responsible for the synthesis of very low-density lipoproteins in the liver and chylomicrons in the intestine. Lomitapide has been approved by the US Food and Drug Administration, European Medicines Agency, and other regulatory agencies for the treatment of hypercholesterolemia in adult patients with homozygous familial hypercholesterolemia. Clinical trials have shown that lomitapide reduces low-density-lipoprotein cholesterol levels by around 40% in homozygous familial hypercholesterolemia patients on treatment with statins with or without low-density-lipoprotein apheresis, with an acceptable safety and tolerance profile. The most common adverse events are gastrointestinal symptoms that decrease in frequency with long-term treatment, and the increase in liver fat remains stable. This review analyzes the clinical use, efficacy, and tolerability of lomitapide.

Inhibition of Angiopoietin-Like Protein 3 With a Monoclonal Antibody Reduces Triglycerides in Hypertriglyceridemia

Supplemental Digital Content is available in the text.

Background:

Hypertriglyceridemia is associated with increased cardiovascular risk and may be caused by impaired lipoprotein clearance. Angiopoietin-like protein 3 (ANGPTL3) inhibits lipoprotein lipase activity, increasing triglycerides and other lipids. Evinacumab, an ANGPTL3 inhibitor, reduced triglycerides in healthy human volunteers and in homozygous familial hypercholesterolemic individuals. Results from 2 Phase 1 studies in hypertriglyceridemic subjects are reported here.

Methods:

Subjects with triglycerides >150 but ≤450 mg/dL and low-density lipoprotein cholesterol ≥100 mg/dL (n=83 for single ascending dose study [SAD]; n=56 for multiple ascending dose study [MAD]) were randomized 3:1 to evinacumab:placebo. SAD subjects received evinacumab subcutaneously at 75/150/250 mg, or intravenously at 5/10/20 mg/kg, monitored up to day 126. MAD subjects received evinacumab subcutaneously at 150/300/450 mg once weekly, 300/450 mg every 2 weeks, or intravenously at 20 mg/kg once every 4 weeks up to day 56 with 6 months of follow-up. The primary outcomes were incidence and severity of treatment-emergent adverse events. Efficacy analyses included changes in triglycerides and other lipids over time.

Results:

In the SAD, 32 (51.6%) versus 9 (42.9%) subjects on evinacumab versus placebo reported treatment-emergent adverse events. In the MAD, 21 (67.7%) versus 9 (75.0%) subjects on subcutaneously evinacumab versus placebo and 6 (85.7%) versus 1 (50.0%) on intravenously evinacumab versus placebo reported treatment-emergent adverse events. No serious treatment-emergent adverse events or events leading to death or treatment discontinuation were reported. Elevations in alanine aminotransferase (7 [11.3%] SAD), aspartate aminotransferase (4 [6.5%] SAD), and creatinine phosphokinase (2 [3.2%) SAD, 1 [14.3%] MAD) were observed with evinacumab (none in the placebo groups), which were single elevations and were not dose-related. Dose-dependent reductions in triglycerides were observed in both studies, with maximum reduction of 76.9% at day 3 with 10 mg/kg intravenously (P<0.0001) in the SAD and of 83.1% at day 2 with 20 mg/kg intravenously once every 4 weeks (P=0.0003) in the MAD. Significant reductions in other lipids were observed with most evinacumab doses versus placebo.

Conclusion:

Evinacumab was well-tolerated in 2 Phase 1 studies. Lipid changes in hypertriglyceridemic subjects were similar to those observed with ANGPTL3 loss-of-function mutations. Because the latter is associated with reduced cardiovascular risk, ANGPTL3 inhibition may improve clinical outcomes.

Clinical Trial Registration:

https://www.clinicaltrials.gov. Unique identifiers: NCT01749878 and NCT02107872.

Treatment Strategy for Dyslipidemia in Cardiovascular Disease Prevention: Focus on Old and New Drugs

Prevention and treatment of dyslipidemia should be considered as an integral part of individual cardiovascular prevention interventions, which should be addressed primarily to those at higher risk who benefit most. To date, statins remain the first-choice therapy, as they have been shown to reduce the risk of major vascular events by lowering low-density lipoprotein cholesterol (LDL-C). However, due to adherence to statin therapy or statin resistance, many patients do not reach LDL-C target levels. Ezetimibe, fibrates, and nicotinic acid represent the second-choice drugs to be used in combination with statins if lipid targets cannot be reached. In addition, anti-PCSK9 drugs (evolocumab and alirocumab) provide an effective solution for patients with familial hypercholesterolemia (FH) and statin intolerance at very high cardiovascular risk. Recently, studies demonstrated the effects of two novel lipid-lowering agents (lomitapide and mipomersen) for the management of homozygous FH by decreasing LDL-C values and reducing cardiovascular events. However, the costs for these new therapies made the cost–effectiveness debate more complicated.

Unmet Needs in LDL-C Lowering: When Statins Won't Do!

The use of low-density lipoprotein cholesterol (LDL-C)-lowering medications has led to a significant reduction of cardiovascular risk in both primary and secondary prevention. Statin therapy, one of the cornerstones for the prevention and treatment of cardiovascular disease (CVD), has been demonstrated to be effective in lowering LDL-C levels and in reducing the risk for CVD and is generally well-tolerated. However, compliance with statins remains suboptimal. One of the main reasons is limitations by adverse events, notably myopathies, which can lead to non-compliance with the prescribed statin regimen. Reducing the burden of elevated LDL-C levels is critical in patients with CVD as well as in patients with very high baseline levels of LDL-C (e.g. patients with familial hypercholesterolaemia), as statin therapy is insufficient for optimally reducing LDL-C below target values. In this review, we discuss alternative treatment options after maximally tolerated doses of statin therapy, including ezetimibe, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, and cholesteryl ester transfer protein (CETP) inhibitors. Difficult-to-treat patients may benefit from combination therapy with ezetimibe or a PCSK9 inhibitor (evolocumab or alirocumab, which are now available). Updates of treatment guidelines are needed to guide the management of patients who will best benefit from these new treatments.

Progress in the care of common inherited atherogenic disorders of apolipoprotein B metabolism

Familial hypercholesterolaemia, familial combined hyperlipidaemia (FCH) and elevated lipoprotein(a) are common, inherited disorders of apolipoprotein B metabolism that markedly accelerate the onset of atherosclerotic cardiovascular disease (ASCVD). These disorders are frequently encountered in clinical lipidology and need to be accurately identified and treated in both index patients and their family members, to prevent the development of premature ASCVD. The optimal screening strategies depend on the patterns of heritability for each condition. Established therapies are widely used along with lifestyle interventions to regulate levels of circulating lipoproteins. New therapeutic strategies are becoming available, and could supplement traditional approaches in the most severe cases, but their long-term cost-effectiveness and safety have yet to be confirmed. We review contemporary developments in the understanding, detection and care of these highly atherogenic disorders of apolipoprotein B metabolism.

Clinical experience of lomitapide therapy in patients with homozygous familial hypercholesterolaemia

The microsomal triglyceride transfer protein (MTP) inhibitor lomitapide is a licenced adjunct to a low-fat diet and other lipid-lowering medication, with or without low-density lipoprotein apheresis, for the treatment of adults with homozygous familial hypercholesterolaemia (HoFH). In a recently published phase 3 study, patients with HoFH received lomitapide in addition to maximally tolerated lipid-lowering therapy. Treatment with lomitapide resulted in a mean approximate 50% reduction in LDL-C levels after 26 weeks compared with baseline levels (p < 0.0001). This decrease in LDL-C was maintained at Weeks 56 and 78 (44% [p < 0.0001] and 38% [p = 0.0001], respectively). This paper offers clinical perspectives based on selected case histories of patients participating in the phase 3 lomitapide study. These cases provide illustrative examples of the efficacy of lomitapide, with or without apheresis, and show that the effective management of adverse effects can enable patients to remain on effective treatment.

Microsomal transfer protein (MTP) inhibition-a novel approach to the treatment of homozygous hypercholesterolemia

Homozygous familial hypercholesterolemia (HoFH) represents the most severe lipoprotein disorder, generally attributable to mutation(s) of the low-density lipoprotein receptor (LDL-R), i.e. autosomal dominant hypercholesterolemia type 1 (ADH1). Much lower percentages are due to alterations of apolipoprotein B (ADH2), or gain-of-function mutations of proprotein convertase subtilisin/kexin type 9 (PCSK9) (ADH3). In certain geographical areas a significant number of patients may be affected by an autosomal recessive hypercholesterolemia (ARH). Mutations may be also combined (two mutations of the same gene, compound heterozygosity), or two in different genes (double heterozygosity). Among the most innovative therapeutic approaches made available recently, inhibitors of the microsomal transfer protein (MTP) system have shown a high clinical potential. MTP plays a critical role in the assembly/secretion of very-low-density lipoproteins (VLDL), and its absence leads to apo B deficiency. MTP antagonists dramatically lower LDL-cholesterol (LDL-C) in animals, although a reported increase of liver fat delayed their clinical development. Lomitapide, the best-studied MTP inhibitor, reduces LDL-C by 50% or more in HoFH patients, with modest, reversible, liver steatosis. Recent US approval has confirmed an acceptable tolerability, provided patients adhere to a strictly low-fat regimen. There are no clinical data on atherosclerosis reduction/regression, but animal models provide encouraging results.

Long-term clinical results of microsomal triglyceride transfer protein inhibitor use in a patient with homozygous familial hypercholesterolemia

We report the case of a 49-year-old woman with homozygous familial hypercholesterolemia and a complicated cardiovascular history, treated for 5 years with a microsomal triglyceride transfer protein inhibitor in addition to her other lipid-lowering therapy.

Current Treatment of Familial Hypercholesterolaemia

Familial hypercholesterolaemia is an autosomal-dominant disorder associated with mutations in the LDL receptor gene resulting in markedly elevated plasma low-density lipoprotein cholesterol levels. FH is significantly underrecognised with as many as 1 in 300 having the heterozygous form and 1 in 1 million having the homozygous form of the disease. Early diagnosis and treatment of FH is paramount to reduce the risk of premature atherosclerotic cardiovascular disease and death. The goal of treatment is to reduce LDL-C by 50 % from baseline levels with lifestyle modification, pharmacologic lipid-lowering therapy, LDL apheresis and in rare cases, liver transplantation. Pharmacologic treatment ranges from statin medications to newer agents such as lomitapide, mipomersin and PCSK9 inhibitors. Combination therapy is frequently required to achieve goal lipoprotein level reductions and prevent complications.