Target achievement and cardiovascular event rates with Lomitapide in homozygous Familial Hypercholesterolaemia

Hypercholesterolemia: a literature review on management using tafolecimab: a novel member of PCSK9 monoclonal antibodies

Background

Cardiovascular diseases (CVD) persist as the leading cause of mortality globally, with atherosclerotic cardiovascular disease (ASCVD), including hypercholesterolaemia, being a significant contributor. Hyperlipidemia management includes various lipid-lowering drugs, including statins, Bempedoic acid, inclisiran, Lomitapide, ANGPTL3 inhibitors, and PCSK9 inhibitors. Statins have traditionally dominated lipid management therapies; however, a subset of patients remains unresponsive or intolerant to this therapy, necessitating novel therapeutic approaches. Tafolecimab, a promising and novel PCSK9 monoclonal antibody, demonstrated significant LDL-C reduction and a favourable safety profile in clinical trials.

Objective

This review aimed to discuss the role and efficacy of Tafolecimab in the management of hypercholesterolaemia.

Methods

The authors searched online databases, including PubMed, Scopus, and Embase, for articles related to talofecimab.

Discussion

The efficacy of Tafolecimab in diverse patient populations, including those with comorbid conditions and various lipid disorders, has been explored. Ongoing trials, such as CREDIT-1, CREDIT-2, and CREDIT-4, have provided valuable insights into Tafolecimab's potential as a lipid-lowering agent. Moreover, the drug's extended dosing interval may enhance patient compliance and reduce treatment costs. It has also been found that Tafolecimab has more affinity for PCSK9 and a longer duration of LDL-C reduction than other monoclonal antibody drugs such as evolocumab. Thus, this review focuses on Tafolecimab, a novel PCSK9 monoclonal antibody, its mechanism of action, clinical trial outcomes, safety profile, and potential role in hypercholesterolaemia management. Despite its assuring potential, the long-term impact of Tafolecimab on cardiovascular outcomes remains to be fully elucidated, necessitating further research. Regulatory authorities like the FDA and EMA should also evaluate Tafolecimab's risks and benefits.

Conclusion

In conclusion, Tafolecimab shows potential as an innovative therapeutic option for hypercholesterolaemia, particularly in patients with specific risk factors, but warrants additional research.

The Effect of PCSK9 Inhibitors on LDL-C Target Achievement in Patients with Homozygous Familial Hypercholesterolemia: A Retrospective Cohort Analysis

INTRODUCTION

Achieving target low-density lipoprotein-cholesterol (LDL-C) levels remains challenging when treating homozygous familial hypercholesterolemia (HoFH). Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) are prescribed in addition to statins and ezetimibe, but patients' response varies and depends on residual low-density lipoprotein receptor (LDLR) function.

METHODS

A multicenter, retrospective observational analysis evaluated LDL-C target achievement in response to PCSK9i treatment in 28 patients with HoFH from the Middle East/North Africa region. Effect of genotype was investigated. Demographic and clinical information was retrospectively obtained from medical records. Patient response to PCSK9i treatment was assessed by calculating percentage changes in lipid levels from pre-PCSK9i treatment baseline to most recent follow-up visit where patients were recorded as receiving PCSK9i on top of standard of care lipid-lowering therapies (LLTs; i.e., statins/ezetimibe) and assessing European Atherosclerosis Society (EAS) target achievement up to January 31, 2022. Lowest LDL-C level while receiving PCSK9i was identified.

RESULTS

The cohort (n = 28) had a mean age (standard deviation; SD) of 22.8 (9.8) years (n = 28) and was 51% female (n = 27). Baseline LDL-C data were available in 24/28 (85.7%) patients (mean [SD] 14.0 [3.0] mmol/L). Median (interquartile range) duration of PCSK9i treatment was 12.0 months (4.0-19.1) months and mean (SD) % change in LDL-C after PCSK9i treatment was - 8.6% (12.1). LDL-C reduction from baseline was below 15% in 17/24 patients (70.8%). In the full cohort, mean (SD) minimum LDL-C during PCSK9i treatment was 11.9 (2.8; n = 28) mmol/L. No patient achieved EAS target LDL-C while receiving PCSK9i; genotype analysis suggested LDLR-null/null patients were most refractory to PCSK9i.

CONCLUSION

Response to PCSK9i was minimal in this cohort of patients with HoFH. No patients achieved EAS LDL-C targets, and most failed to reach the EAS-recommended 15% LDL-C reduction for PCSK9i therapy continuation. These results suggest additional LLTs are necessary to achieve LDL-C targets in HoFH.

Efficacy, Safety, and Tolerability of Inclisiran in Patients With Homozygous Familial Hypercholesterolemia: Results From the ORION-5 Randomized Clinical Trial

BACKGROUND

Homozygous familial hypercholesterolemia is a genetic disease characterized by extremely high levels of low-density lipoprotein cholesterol (LDL-C) and a high risk of premature cardiovascular events. The proof-of-concept study ORION-2 (A Study of Inclisiran in Participants With Homozygous Familial Hypercholesterolemia) showed that inclisiran, a small interfering RNA that prevents production of the hepatic PCSK9 protein (proprotein convertase subtilisin/kexin type 9), could lead to durable reductions in LDL-C levels when added to statins and ezetimibe in patients with homozygous familial hypercholesterolemia.

METHODS

ORION-5 was a phase 3, 2-part, multicenter study in 56 patients with homozygous familial hypercholesterolemia and elevated LDL-C levels despite maximum tolerated doses of LDL-C-lowering therapies with or without lipoprotein apheresis. Patients eligible for part 1 (double-blind, 6 months) were randomized 2:1 to receive either 300 mg of inclisiran sodium (equivalent to 284 mg of inclisiran) or placebo. Placebo-treated patients from part 1 were transitioned to inclisiran in part 2 (open-label, 18 months). The primary end point was the percentage change in LDL-C levels from baseline to day 150.

RESULTS

The mean age of the patients was 42.7 years, and 60.7% were women. The mean baseline LDL-C levels were 294.0 mg/dL and 356.7 mg/dL in the inclisiran and placebo groups, respectively. The placebo-corrected percentage change in LDL-C level from baseline to day 150 was -1.68% (95% CI, -29.19% to 25.83%; P=0.90), and the difference was not statistically significant between the inclisiran and placebo groups. The placebo-corrected percentage change in PCSK9 levels from baseline to day 150 was -60.6% with inclisiran treatment (P<0.0001); this was sustained throughout the study, confirming the effect of inclisiran on its biological target of PCSK9. No statistically significant differences between the inclisiran and placebo groups were observed in the levels of other lipids and lipoproteins (apolipoprotein B, total cholesterol, and non-high-density lipoprotein cholesterol). Adverse events and serious adverse events did not differ between the inclisiran and placebo groups throughout the study.

CONCLUSIONS

Inclisiran treatment did not reduce LDL-C levels in patients with homozygous familial hypercholesterolemia despite substantial lowering of PCSK9 levels. Inclisiran was well-tolerated, and the safety findings were consistent with previously reported studies and the overall safety profile.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03851705.

VLDL Biogenesis and Secretion: It Takes a Village

The production and secretion of VLDLs (very-low-density lipoproteins) by hepatocytes has a direct impact on liver fat content, as well as the concentrations of cholesterol and triglycerides in the circulation and thus affects both liver and cardiovascular health, respectively. Importantly, insulin resistance, excess caloric intake, and lack of physical activity are associated with overproduction of VLDL, hepatic steatosis, and increased plasma levels of atherogenic lipoproteins. Cholesterol and triglycerides in remnant particles generated by VLDL lipolysis are risk factors for atherosclerotic cardiovascular disease and have garnered increasing attention over the last few decades. Presently, however, increased risk of atherosclerosis is not the only concern when considering today's cardiometabolic patients, as they often also experience hepatic steatosis, a prevalent disorder that can progress to steatohepatitis and cirrhosis. This duality of metabolic risk highlights the importance of understanding the molecular regulation of the biogenesis of VLDL, the lipoprotein that transports triglycerides and cholesterol out of the liver. Fortunately, there has been a resurgence of interest in the intracellular assembly, trafficking, degradation, and secretion of VLDL by hepatocytes, which has led to many exciting new molecular insights that are the topic of this review. Increasing our understanding of the biology of this pathway will aid to the identification of novel therapeutic targets to improve both the cardiovascular and the hepatic health of cardiometabolic patients. This review focuses, for the first time, on this duality.

New Biological Therapies for Low-Density Lipoprotein Cholesterol

Depressed low-density lipoprotein cholesterol concentration protects against atherosclerotic cardiovascular disease. Natural hypocholesterolemia states can have a monogenic etiology, caused by pathogenic loss of function variants in the PCSK9, ANGPTL3, MTTP, or APOB genes. In this focused review, we discuss development and clinical use of several new therapeutics that inhibit these gene products to target elevated levels of low-density lipoprotein cholesterol. In particular, inhibitors of proprotein convertase subtilisin kexin type 9 (PCSK9) have notably affected clinical practice, followed recently by inhibition of angiopoietin-like 3 (ANGPTL3). Currently used in the clinic are alirocumab and evolocumab, two anti-PCSK9 monoclonal antibodies, inclisiran, a small interfering RNA that prevents PCSK9 translation, evinacumab, an anti-ANGPTL3 monoclonal antibody, and lomitapide, a small-molecule inhibitor of microsomal triglyceride transfer protein. Additional therapies are in preclinical or clinical trial stages of development. These consist of other monoclonal antibodies, antisense oligonucleotides, small-molecule inhibitors, mimetic peptides, adnectins, vaccines, and gene-editing therapies. Vaccines and gene-editing therapies in particular hold great potential to confer active long-term attenuation or provide single-treatment life-long knock-down of PCSK9 or ANGPTL3 activity. Biologic therapies inspired by monogenic hypocholesterolemia states are becoming valuable tools to help protect against atherosclerotic cardiovascular disease.

Advances in Treatment of Dyslipidemia

Dyslipidemias have emerged as prevalent disorders among patients, posing significant risks for the development and progression of cardiovascular diseases. These conditions are characterized by elevated levels of total cholesterol (TC), triglycerides (TGs), and low-density lipoprotein cholesterol (LDL-C). This review delves into the current treatment approach, focusing on equalizing these parameters while enhancing the overall quality of life for patients. Through an extensive analysis of clinical trials, we identify disorders that necessitate alternative treatment strategies, notably familial hypercholesterolemia. The primary objective of this review is to consolidate existing information concerning drugs with the potential to revolutionize dyslipidemia management significantly. Among these promising pharmaceuticals, we highlight alirocumab, bempedoic acid, antisense oligonucleotides, angiopoietin-like protein inhibitors, apolipoprotein C-III (APOC3) inhibitors, lomitapide, and cholesterol ester transfer protein (CETP) inhibitors. Our review demonstrates the pivotal roles played by each of these drugs in targeting specific parameters of lipid metabolism. We outline the future landscape of dyslipidemia treatment, envisaging a more tailored and effective therapeutic approach to address this widespread medical concern.

Low cholesterol states: clinical implications and management

INTRODUCTION

Hypocholesterolemia results from genetic - both monogenic and polygenic - and non-genetic causes and can sometimes be a source of clinical concern. We review etiologies and sequelae of hypocholesterolemia and therapeutics inspired from genetic hypocholesterolemia.

AREAS COVERED

Monogenic hypocholesterolemia disorders caused by the complete absence of apolipoprotein (apo) B-containing lipoproteins (abetalipoproteinemia and homozygous hypobetalipoproteinemia) or an isolated absence of apo B-48 lipoproteinemia (chylomicron retention disease) lead to clinical sequelae. These include gastrointestinal disturbances and severe vitamin deficiencies that affect multiple body systems, i.e. neurological, musculoskeletal, ophthalmological, and hematological. Monogenic hypocholesterolemia disorders with reduced but not absent levels of apo B lipoproteins have a milder clinical presentation and patients are protected against atherosclerotic cardiovascular disease. Patients with heterozygous hypobetalipoproteinemia have somewhat increased risk of hepatic disease, while patients with PCSK9 deficiency, ANGPTL3 deficiency, and polygenic hypocholesterolemia typically have anunremarkable clinical presentation.

EXPERT OPINION

In patients with severe monogenic hypocholesterolemia, early initiation of high-dose vitamin therapy and a low-fat diet are essential for optimal prognosis. The molecular basis of monogenic hypocholesterolemia has inspired novel therapeutics to help patients with the opposite phenotype - i.e. elevated apo B-containing lipoproteins. In particular, inhibitors of PCSK9 and ANGPTL3 show important clinical impact.

Long-term hepatic safety of lomitapide in homozygous familial hypercholesterolaemia

INTRODUCTION

Lomitapide is a microsomal triglyceride transfer protein inhibitor for patients with homozygous familial hypercholesterolaemia. Due to its mechanism of action, potential hepatic effects of lomitapide are of clinical interest. This study aimed to determine the long-term hepatic safety of lomitapide.

METHODS

Data were aggregated from the pivotal phase 3 and extension phase clinical trial with lomitapide (median 5.1 years; serum total bilirubin, transaminases, cytokeratin-18 [CK-18] and enhanced liver fibrosis [ELF] score, fat-soluble vitamins and essential fatty acids), 8-year data from the Lomitapide Observational Worldwide Evaluation Registry (LOWER) and real-world evidence from a cohort of patients treated with lomitapide in Italy (hepatic elastography, and FIB-4 score for hepatic fibrosis).

RESULTS

In the phase 3 trial and the LOWER registry, any asymptomatic excursions in liver transaminase levels were not associated with elevations in bilirubin, and no Hy's law cases were detected in up to 8 years follow-up. There were no clinically relevant increases among hepatic biomarkers CK-18, CK-18 fragments or ELF score and fat-soluble vitamins and essential fatty acids remained above normal levels. In 34 patients treated in Italy with lomita pide for more than 9  years, elevations in hepatic fat were mild-to-moderate; hepatic stiffness remained normal, and the mean FIB-4 score remained below the fibrosis threshold value of 2.67.

CONCLUSIONS

These data indicate that the hepatic safety of lomitapide remains favourable with no clinically significant elevations in hepatic biomarkers and hepatic stiffness remained normal for more than 9 years follow-up. PHASE 3 TRIAL: NCT00730236; extension phase: NCT00943306; LOWER: NCT02135705.

Long-Term Efficacy and Safety of Evinacumab in Patients with Homozygous Familial Hypercholesterolemia: Real-World Clinical Experience

Homozygous familial hypercholesterolemia (HoFH) is a rare, genetic condition characterized by markedly elevated plasma low-density lipoprotein cholesterol (LDL-C) concentrations from birth and increased risk of premature atherosclerotic cardiovascular disease. Evinacumab is an inhibitor of angiopoietin-like 3 protein that offers a new approach for correcting high LDL-C in HoFH. Evinacumab was administered intravenously (15 mg/kg Q4W) for 24 months in 7 patients with genetically confirmed HoFH, receiving background lipoprotein apheresis (LA) and/or lipid-lowering treatment (LLT). Assessment of efficacy and safety were carried out before and after 24 months of evinacumab treatment. The LDL-C lowering effect of evinacumab without LA were also investigated in the 7 HoFH patients after a subsequent compassionate extension period. Twenty-four months of treatment with evinacumab against background LA and LLT resulted in a significant reduction in LDL-C (−46.8%; p < 0.001). LDL-C reduction with evinacumab was maintained during the compassionate extensions period in the absence of treatment with LA (−43.4%; mean follow-up of 208 ± 90 days). Evinacumab was well-tolerated, with no major adverse event reported or significant changes in liver and muscle enzyme concentrations. Our findings suggest that evinacumab is a safe and effective treatment for patients with HoFH receiving best standard of care in a routine setting.

Is Liver Transplant Curative in Homozygous Familial Hypercholesterolemia? A Review of Nine Global Cases

INTRODUCTION

Homozygous familial hypercholesterolemia (HoFH) is a rare, life-threatening, inherited condition characterized by extremely elevated levels of low-density lipoprotein cholesterol (LDL-C). Patients are at high risk of atherosclerotic cardiovascular disease, adverse cardiovascular events, and associated early mortality. Liver transplant is sometimes used with curative intent. The objective of the current case series was to evaluate the follow-up of a range of patients who have undergone liver transplant for the treatment of HoFH.

METHODS

Patients with clinical and/or genetic diagnoses of HoFH were treated according to local practices in four units in Europe and the Middle East. All patients underwent liver transplantation. Baseline and long-term follow-up data were collected, including LDL-C levels, DNA mutations, lipid-lowering medications, and complications due to surgery and immunosuppressive therapy.

RESULTS

Nine patients were included with up to 22 years' follow-up (mean ± SD 11.7 ± 11.7 years; range 0.5-28 years). Three of the patients died as a result of complications of transplant surgery (mortality rate 33%). Among the surviving six patients, four required continued lipid-lowering therapy (LLT) to maintain LDL-C levels and two patients show signs of increasing LDL-C levels that require management. One case (11%) required two consecutive transplants to achieve a viable graft and is awaiting a third transplant because of graft failure.

CONCLUSIONS

Liver transplant did not enable attainment of recommended LDL-C targets in most patients with HoFH, and the majority of patients still required post-transplant LLT. Liver transplant was not curative in most of the patients with HoFH followed. Guidelines suggest that transplant is a treatment of last resort if contemporary treatments are not available or possible.

A Case Series Assessing the Effects of Lomitapide on Carotid Intima-Media Thickness in Adult Patients with Homozygous Familial Hypercholesterolaemia in a Real-World Setting

INTRODUCTION

Homozygous familial hypercholesterolaemia (HoFH) is characterised by extremely elevated levels of low-density lipoprotein cholesterol (LDL-C) and results from multiple mutations in genes affecting the LDL receptor pathway. Patients are at risk of premature atherosclerotic cardiovascular disease (ASCVD) and premature death. Lomitapide is a microsomal triglyceride transfer protein inhibitor developed to treat HoFH, but cardiovascular outcome data are lacking.

METHODS

We evaluated detailed data from five HoFH patients and one patient with heterozygous FH (HeFH) and a very severe phenotype. We also analysed confirmatory data from a further 8 HoFH cases. In total, we analysed data from patients in seven global centres in six countries who were all treated with lomitapide with long-term follow-up. Carotid intima-media thickness (CIMT) imaging was recorded on an ad hoc basis to monitor ASCVD in HoFH.

RESULTS

Lomitapide resulted in marked decreases in LDL-C of 56.8-93.9% [77.7-93.9% in the 6 initial cases (mean nadir 64.8 ± 30.1 mg/dL); 56.8-86.0% in the 8 confirmatory cases (mean nadir 131.4 ± 38.2 mg/dL)]. CIMT regressed in 50% of cases (mean follow-up 5.0 ± 3.1 years in initial six cases, and 4.4 ± 1.4 years in confirmatory cases). In the remaining patients, CIMT showed little further change. In patients where assessments of plaque area were available, regression or stabilisation in CIMT was accompanied by clinically significant regression of plaque area.

CONCLUSIONS

Lomitapide reduces LDL-C levels in patients with HoFH and severe LDL-C phenotypes, and results in stabilisation and/or regression of CIMT, which is an established marker of ASCVD risk. Additional data are needed to determine if this confers a survival benefit in these very high-risk patients.

The Role of Non-statin Lipid-Lowering Medications in Youth with Hypercholesterolemia

PURPOSE OF REVIEW

Lifestyle modification is additive to lipid-lowering medications in the treatment of heterozygous familial hypercholesterolemia (HeFH), which does not respond sufficiently to statin therapy. While both are also important in homozygous familial hypercholesterolemia (HoFH), additional measures such as apheresis may be needed. The purpose of this review is to identify non-statin medications to lower cholesterol that are available for children and adolescents as adjunctive therapy.

RECENT FINDINGS

Ezetimibe is commonly used as second-line pharmacotherapy for treatment of HeFH and HoFH. Colesevelam, a bile acid sequestrant, may be considered for adjunct therapy. Since 2015, the PCSK9 inhibitor evolocumab has been available for adolescents, and its FDA approval has now expanded to age 10 years. The ANGPTL3 inhibitor evinacumab has been approved for children age 12 years and older. A clinical trial for lomitapide is in progress. Approvals for PCSK9 and ANGPTL3 inhibitors have expanded opportunities for children and adolescents with HeFH and HoFH to achieve lower LDL-C levels.

Vaccine targeting ANGPTL3 ameliorates dyslipidemia and associated diseases in mouse models of obese dyslipidemia and familial hypercholesterolemia

Dyslipidemia is a risk factor for cardiovascular disease (CVD), a major cause of death worldwide. Angiopoietin-like protein 3 (ANGPTL3), recognized as a new therapeutic target for dyslipidemia, regulates the metabolism of low-density lipoprotein-cholesterol (LDL-C) and triglycerides. Here, we design 3 epitopes (E1-E3) for use in development of a peptide vaccine targeting ANGPTL3 and estimate effects of each on obesity-associated dyslipidemia in B6.Cg-Lepob /J (ob/ob) mice. Vaccination with the E3 (32EPKSRFAMLD41) peptide significantly reduces circulating levels of triglycerides, LDL-C, and small dense (sd)-LDL-C in ob/ob mice and decreases obese-induced fatty liver. Moreover, E3 vaccination does not induce cytotoxicity in ob/ob mice. Interestingly, the effect of E3 vaccination on dyslipidemia attenuates development of atherosclerosis in B6.KOR/StmSlc-Apoeshl mice fed a high-cholesterol diet, which represent a model of severe familial hypercholesterolemia (FH) caused by ApoE loss of function. Taken together, ANGPTL3 vaccination could be an effective therapeutic strategy against dyslipidemia and associated diseases.

PoLA/CFPiP/PCS/PSLD/PSD/PSH guidelines on diagnosis and therapy of lipid disorders in Poland 2021

In Poland there are still nearly 20 million individuals with hypercholesterolaemia, most of them are unaware of their condition; that is also why only ca. 5% of patients with familial hypercholesterolaemia have been diagnosed; that is why other rare cholesterol metabolism disorders are so rarely diagnosed in Poland. Let us hope that these guidelines, being an effect of work of experts representing 6 main scientific societies, as well as the network of PoLA lipid centers being a part of the EAS lipid centers, certification of lipidologists by PoLA, or the growing number of centers for rare diseases, with a network planned by the Ministry of Health, improvements in coordinated care for patients after myocardial infarction (KOS-Zawał), reimbursement of innovative agents, as well as introduction in Poland of an effective primary prevention program, will make improvement in relation to these unmet needs in diagnostics and treatment of lipid disorders possible.

Novel therapeutic targets and agents for pediatric dyslipidemia

Landmark studies have convincingly demonstrated that atherosclerosis begins in youth. While generally asymptomatic, an increasing number of youth with disorders of lipid and lipoprotein metabolism, such as familial hypercholesterolemia, are being identified through selective and universal screening. While a heart healthy lifestyle is the foundation of treatment for all youth with dyslipidemia, lipid-lowering therapy may be required by some to prevent morbidity and premature mortality, especially when initiated at a young age. When appropriate, use of statins has become standard of care for reducing low-density lipoprotein cholesterol, while fibrates may be beneficial in helping to lower triglycerides. Many therapeutic options commonly used in adults are not yet approved for use in youth less than 18 years of age. Although currently available lipid-lowering therapy is well tolerated and safe when administered to youth, response to treatment may vary and some conditions lack an efficient therapeutic option. Thus, newer agents are needed to aid in management. Many are in development and clinical trials in youth are currently in progress but will require FDA approval before becoming commercially available. Many utilize novel approaches to favorably alter lipid and lipoprotein metabolism. In the absence of long-term outcome data of youth who were treated beginning at an early age, clinical registries may prove to be useful in monitoring safety and efficacy and help to inform clinical decision-making. In this manuscript, we review currently available and novel therapeutic agents in development for the treatment of elevated cholesterol and triglycerides.

Management of Familial Hypercholesterolemia: Current Status and Future Perspectives

Familial hypercholesterolemia (FH) is the most common monogenic disorder associated with premature atherosclerotic cardiovascular disease. Early diagnosis and effective treatment can significantly improve prognosis. Recent advances in the field of lipid metabolism have shed light on the molecular defects in FH and new therapeutic options have emerged. A search of PubMed database up to March 2020 was performed for this review using the following keywords: “familial hypercholesterolemia,” “diagnosis,” “management,” “guideline,” “consensus,” “genetics,” “screening,” “lipid lowering agents.” The prevalence rate of heterozygous FH is approximately 1 in 200 to 250 and FH is underdiagnosed and undertreated in many parts of the world. Diagnostic criteria have been developed to aid the clinical diagnosis of FH. Genetic testing is now available but not widely used. Cascade screening is recommended to identify affected family members, and the benefits of early interventions are clear. Treatment strategy and target is currently based on low-density lipoprotein (LDL) cholesterol levels as the prognosis of FH largely depends on the magnitude of LDL cholesterol-lowering that can be achieved by lipid-lowering therapies. Statins with or without ezetimibe are the mainstay of treatment and are cost-effective. Addition of newer medications like PCSK9 inhibitors is able to further lower LDL cholesterol levels substantially, but the cost is high. Lipoprotein apheresis is indicated in homozygous FH or severe heterozygous FH patients with inadequate response to cholesterol-lowering therapies. In conclusion, FH is a common, treatable genetic disorder, and although our understanding of this disease has improved, many challenges still remain for its optimal management.

Evinacumab for Homozygous Familial Hypercholesterolemia

BACKGROUND

Homozygous familial hypercholesterolemia is characterized by premature cardiovascular disease caused by markedly elevated levels of low-density lipoprotein (LDL) cholesterol. This disorder is associated with genetic variants that result in virtually absent (null-null) or impaired (non-null) LDL-receptor activity. Loss-of-function variants in the gene encoding angiopoietin-like 3 (ANGPTL3) are associated with hypolipidemia and protection against atherosclerotic cardiovascular disease. Evinacumab, a monoclonal antibody against ANGPTL3, has shown potential benefit in patients with homozygous familial hypercholesterolemia.

METHODS

In this double-blind, placebo-controlled, phase 3 trial, we randomly assigned in a 2:1 ratio 65 patients with homozygous familial hypercholesterolemia who were receiving stable lipid-lowering therapy to receive an intravenous infusion of evinacumab (at a dose of 15 mg per kilogram of body weight) every 4 weeks or placebo. The primary outcome was the percent change from baseline in the LDL cholesterol level at week 24.

RESULTS

The mean baseline LDL cholesterol level in the two groups was 255.1 mg per deciliter, despite the receipt of maximum doses of background lipid-lowering therapy. At week 24, patients in the evinacumab group had a relative reduction from baseline in the LDL cholesterol level of 47.1%, as compared with an increase of 1.9% in the placebo group, for a between-group least-squares mean difference of -49.0 percentage points (95% confidence interval [CI], -65.0 to -33.1; P<0.001); the between-group least-squares mean absolute difference in the LDL cholesterol level was -132.1 mg per deciliter (95% CI, -175.3 to -88.9; P<0.001). The LDL cholesterol level was lower in the evinacumab group than in the placebo group in patients with null-null variants (-43.4% vs. +16.2%) and in those with non-null variants (-49.1% vs. -3.8%). Adverse events were similar in the two groups.

CONCLUSIONS

In patients with homozygous familial hypercholesterolemia receiving maximum doses of lipid-lowering therapy, the reduction from baseline in the LDL cholesterol level in the evinacumab group, as compared with the small increase in the placebo group, resulted in a between-group difference of 49.0 percentage points at 24 weeks. (Funded by Regeneron Pharmaceuticals; ELIPSE HoFH ClinicalTrials.gov number, NCT03399786.).

Lomitapide-a Microsomal Triglyceride Transfer Protein Inhibitor for Homozygous Familial Hypercholesterolemia

PURPOSE OF REVIEW

Homozygous familial hypercholesterolemia (HoFH) is a rare, genetic condition characterized by high levels of Low density lipoprotein cholesterol (LDL-C); overt, early-onset atherosclerotic cardiovascular disease (ASCVD); and premature cardiovascular events and mortality. Lomitapide is a first-in-class microsomal triglyceride transfer protein inhibitor for the treatment of HoFH. This review provides an update on data emerging from real-world studies of lomitapide following on from its pivotal phase 3 clinical trial in HoFH.

RECENT FINDINGS

Recent registry data have confirmed that HoFH is characterized by delayed diagnosis, with many patients not receiving effective therapy until they are approaching the age when major adverse cardiovascular events may occur. Data from case series of varying sizes, and from a 163-patient registry of HoFH patients receiving lomitapide, have demonstrated that lomitapide doses are lower and adverse events less severe than in the phase 3 study. Lomitapide enables many patients to reach European Atherosclerosis Society LDL-C targets. Some patients are able to reduce frequency of lipoprotein apheresis or, in some cases, stop the procedure altogether-unless there is significant elevation of lipoprotein (a). Modelling analyses based on historical and clinical trial data indicate that lomitapide has the potential to improve cardiovascular outcomes and survival in HoFH. Real-world clinical experience with lomitapide has shown the drug to be effective with manageable, less marked adverse events than in formal clinical studies. Event modelling data suggest a survival benefit with lomitapide in HoFH.

Homozygous familial hypercholesterolemia in a young woman with dual gene mutations of low-density lipoprotein receptor and proprotein convertase subtilisin/kexin type 9

A 28-year-old woman with a rare combination of homozygous LDLR and heterozygous PCSK9 mutations had a phenotype consistent with homozygous familial hypercholesterolemia. She reported a clinical history of coronary and extracoronary atherosclerosis treated with 3 coronary stenting procedures, one coronary bypass, and aortic and mitral valve replacements. Because the patient refused lipoprotein apheresis, lipid-lowering therapy with statins, ezetimibe, and evolocumab was started. The desired low-density lipoprotein cholesterol target was not achieved. Dose-escalated lomitapide therapy (up to 30 mg/d) was added, enabling achievement of low-density lipoprotein cholesterol levels of 45 mg/dL during 24 months' follow-up. During this period, no cardiovascular events or clinical evidence of side effects occurred. In this case, lomitapide has been used in combination with maximum-tolerated statin therapy to successfully treat a patient with a rare combination of mutations in both LDLR and PCSK9 genes.

Case Report: Cardiac Surgery and Combined Lipid-Lowering Drug Therapy for Homozygous Familial Hypercholesterolemia

Homozygous familial hypercholesterolemia (HoFH) is a rare, autosomal dominant, hereditary, metabolic disease. HoFH patients exhibit severe coronary stenosis and valvular disease, which may result in sudden death, even during adolescence. The challenges faced during surgery and the poor curative effect of conventional lipid-lowering therapy create a treatment bottleneck. We report a rare case of HoFH in a 12-years-old boy with acute myocardial infarction, severe mitral insufficiency, and moderate aortic insufficiency. Coronary artery bypass grafting and valvuloplasty resulted in improved heart function. Postoperative combined lipid-lowering drug therapy was able to reduce low-density lipoprotein cholesterol level from 15.37 mm/L to 6.41 mmol/L. Thus, the combination of medical and surgical treatment was considered effective and can be used to inform treatment guidelines for HoFH with severe complications.

Lomitapide and Mipomersen-Inhibiting Microsomal Triglyceride Transfer Protein (MTP) and apoB100 Synthesis

PURPOSE OF REVIEW

The goal of this review is to evaluate the role of inhibiting the synthesis of lipoproteins when there is no or little residual LDL-receptor function as in patients with homozygous familial hypercholesterolaemia. Lomitapide is administered orally once a day while mipomersen is given by subcutaneous injection once a week. Lomitapide inhibits microsomal triglyceride transfer protein while mipomersen is an antisense oligonucleotide directed against apoB100.

RECENT FINDINGS

The pivotal registration trials for lomitapide and mipomersen were published in 2013 and 2010, respectively. More recently published data from extension trials and cohort studies provides additional information on long-term safety and efficacy. The mean LDL cholesterol reduction was 50% with lomitapide in its single-arm open-label registration trial. Mipomersen reduced LDL cholesterol by approximately 25% in its double-blind, placebo-controlled registration study. Both lomitapide and mipomersen therapy are associated with variable increases in hepatic fat content. The long-term safety of increased hepatic fat content in patients receiving these therapies is uncertain and requires further study. Both drugs may cause elevated transaminase in some patients, but no cases of severe liver injury have been reported. Lomitapide may also cause gastrointestinal discomfort and diarrhoea, especially if patients consume high-fat meals and patients are advised to follow a low-fat diet supplemented with essential fatty acids and fat-soluble vitamins. Mipomersen may cause injection-site and influenza-like reactions. The effect of lomitapide and mipomersen on cardiovascular outcomes has not been studied, but circumstantial evidence suggests that the LDL cholesterol lowering achieved with these two agents may reduce cardiovascular event rates.

Microsomal triglyceride transfer protein inhibitor (lomitapide) efficacy in the treatment of patients with homozygous familial hypercholesterolaemia

Aims

The aim of this study was to evaluate the effect of microsomal triglyceride transfer protein inhibitor (lomitapide) in patients with homozygous familial hypercholesterolaemia.

Methods and results

In 12 homozygous familial hypercholesterolaemia patients treated with lipid-lowering drugs ± biweekly lipoprotein apheresis sessions (nine patients), daily lomitapide was added. The lipid profile (total cholesterol, low-density lipoprotein cholesterol, triglycerides, high-density lipoprotein cholesterol) before and after lomitapide treatment was evaluated. The follow-up period with lomitapide treatment was 3–24 months (13.8 ± 7.9). The median baseline low-density lipoprotein cholesterol level was 900 mg/dl (348–1070), after lipid-lowering drugs therapy was 383.5 mg/dl (214–866) and after lipid-lowering drugs + time-averaged level was 288 mg/dl (183.7–716.6). The addition of lomitapide lowered low-density lipoprotein cholesterol levels further by 56.8% compared to lipid-lowering drugs alone (mean reduction 262, 95% confidence interval (105.5–418.7), p = 0.005) and by 54% (mean reduction 182.9, 95% confidence interval (−342 – −23), p = 0.031) comparing to lipid-lowering drugs + lipoprotein apheresis (time-averaged level). The time-averaged level of low-density lipoprotein cholesterol in lipid-lowering drugs + lipoprotein apheresis patients compared with lipid-lowering drugs + lomitapide was 54% in favour of lomitapide ( p = 0.031).

Conclusions

Treatment with lomitapide in homozygous familial hypercholesterolaemia patients has a beneficial effect with a constant decrease of low-density lipoprotein cholesterol by 57% compared with classical lipid-lowering therapy and by 54% compared with classical lipid-lowering therapy and time-averaged level of low-density lipoprotein cholesterol.

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.

Real-World Outcomes with Lomitapide Use in Paediatric Patients with Homozygous Familial Hypercholesterolaemia

INTRODUCTION

Homozygous familial hypercholesterolaemia (HoFH) is a rare, autosomal disease affecting the clearance of low-density lipoprotein cholesterol (LDL-C) from circulation, and leading to early-onset atherosclerotic cardiovascular disease (ASCVD). Treatment consists mainly of statins, lipoprotein apheresis (LA) and, more recently, the microsomal triglyceride transfer protein inhibitor lomitapide. Lomitapide is not licensed for use in children, but has been made available through an expanded access programme or on a named patient basis.

METHODS

This case series includes 11 HoFH patients in 10 different centres in eight countries, less than 18 years of age (mean 11.6 ± 1.1 years, 64% male), with signs of ASCVD, and who have received treatment with lomitapide (mean dose 24.5 ± 4.3 mg/day; mean exposure 20.0 ± 2.9 months). Background lipid-lowering therapy was given according to local protocols. Lomitapide was commenced with a stepwise dose escalation from 2.5 mg or 5 mg/day; dietary advice and vitamin supplements were provided as per the product label for adults. Laboratory analysis was conducted as part of regular clinical care.

RESULTS

In the 11 cases, mean baseline LDL-C was 419 ± 74.6 mg/dL and was markedly reduced by lomitapide to a nadir of 176.7 ± 46.3 mg/dL (58.4 ± 6.8% decrease). Six patients achieved recommended target levels for children below 135 mg/dL, five of whom had LA frequency reduced. In one case, LDL-C levels were close to target when lomitapide was started but remained stable despite 75% reduction in LA frequency (from twice weekly to biweekly). Adverse events were mainly gastrointestinal in nature, occurred early in the treatment course and were well managed. Three patients with excursions in liver function tests were managed chiefly without intervention; two patients had decreases in lomitapide dose.

CONCLUSIONS

Lomitapide demonstrated promising effectiveness in paediatric HoFH patients. Adverse events were manageable, and the clinical profile of the drug is apparently similar to that in adult patients.

FUNDING

Amryt Pharma.