Improved lipid-lowering treatment and reduction in cardiovascular disease burden in homozygous familial hypercholesterolemia: The SAFEHEART follow-up study

AIM

We aimed to describe clinical and genetic characteristics, lipid-lowering treatment and atherosclerotic cardiovascular disease (ASCVD) outcomes over a long-term follow-up in homozygous familial hypercholesterolemia (HoFH).

METHODS

SAFEHEART (Spanish Familial Hypercholesterolaemia Cohort Study) is a long-term study in molecularly diagnosed FH. Data analyzed in HoFH were prospectively obtained from 2004 until 2022. ASCVD events, lipid profile and lipid-lowering treatment were determined.

RESULTS

Thirty-nine HoFH patients were analyzed. The mean age was 42 ± 20 years and nineteen (49%) were women. Median follow-up was 11 years (IQR 6,18). Median age at genetic diagnosis was 24 years (IQR 8,42). At enrolment, 33% had ASCVD and 18% had aortic valve disease. Patients with new ASCVD events and aortic valve disease at follow-up were six (15%), and one (3%), respectively. Median untreated LDL-C levels were 555 mg/dL (IQ 413,800), and median LDL-C levels at last follow-up was 122 mg/dL (IQR 91,172). Most patients (92%) were on high intensity statins and ezetimibe, 28% with PCSK9i, 26% with lomitapide, and 23% with lipoprotein-apheresis. Fourteen patients (36%) attained an LDL-C level below 100 mg/dL, and 10% attained an LDL-C below 70 mg/dL in secondary prevention. Patients with null/null variants were youngers, had higher untreated LDL-C and had the first ASCVD event earlier. Free-event survival is longer in patients with defective variant compared with those patients with at least one null variant (p=0.02).

CONCLUSIONS

HoFH is a severe life threating disease with a high genetic and phenotypic variability. The improvement in lipid-lowering treatment and LDL-C levels have contributed to reduce ASCVD events.

Modern approaches to the management of homozygous familial hypercholesterolemia in the Middle East and North Africa

Homozygous familial hypercholesterolaemia (HoFH) is a severe form of FH in which inheritance of two defective or null mutations in genes associated with metabolism of low-density lipoprotein cholesterol (LDL-C) results in extremely high LDL-C, premature atherosclerotic cardiovascular disease (ASCVD) and mortality. Treatment of HoFH comprises a multi-modal approach of statins, ezetimibe, lipoprotein apheresis; and inhibitors of proprotein convertase subtilisin/kexin type, angiopoietin-like protein 3 (ANGPTL3) and microsomal triglyceride transfer protein. These treatments are generally costly, and patients also often require treatment for ASCVD consequent to HoFH. Therefore, in the interests of both economics and preservation of life, disease prevention via genetic screening and counselling is rapidly becoming a key element in the overall management of HoFH. Guidelines are available to assist diagnosis and treatment of HoFH; however, while advancements have been made in the management of the disease, there has been little systematic attention paid to prevention. Additionally, the Middle East/North Africa (MENA) region has a higher prevalence of HoFH than most other regions - chiefly due to consanguinity. This has led to the establishment of regional lipid clinics and awareness programs that have thrown education and awareness of HoFH into sharp focus. Incorporation of principles of prevention, education, awareness, and data from real-world use of existing therapeutics will significantly enhance the effectiveness of future guidelines for the management of HoFH, particularly in the MENA region.

Sex differences in the presentation, treatment and outcomes of patients with homozygous familial hypercholesterolemia

BACKGROUND

Homozygous familial hypercholesterolemia (HoFH) is a rare, autosomal semi-dominant lipid metabolism disorder characterized by extremely high low-density lipoprotein cholesterol (LDL-C) levels and premature cardiovascular disease. The objective of this study was to investigate sex-differences in the treatment and outcomes of patients with HoFH.

METHODS

We examined clinical characteristics, lipid-lowering therapy (LLT), and cardiovascular events using descriptive statistics of patients in the Canadian HoFH registry. Major adverse cardiovascular events (MACE) were defined as the composite of cardiovascular death, non-fatal myocardial infarction, and stroke. Sex differences between continuous and categorical variables were analyzed using Mann-Whitney U test and Fisher's Exact test, respectively.

RESULTS

This study included 48 patients (27 (56%) female). The median age at diagnosis in females was 14.0 (interquartile range (IQR) 9.0-30.0) and in males was 8.0 (IQR 2.0-23.0) (p = 0.07). Baseline clinical characteristics were comparable between both sexes. The median baseline LDL-C was 12.7 mmol/L (10.0-18.3) in females and 15.3 (10.5-20.0) in males (p = 0.51). Follow up LDL-C levels were 7.6 mmol/L (IQR 4.8-11.0) in females and 6.3 (IQR 4.6-7.5) in males (p = 0.1). Most patients were taking 3 or more LLTs, with comparable proportions in both sexes (p = 0.26). Apheresis was similar in both sexes, 14 (51.8%) vs. 10 (47.6%) (p = 0.2). Over a mean of 10 years of follow-up, MACE occurred in 3 females (11.1%) and 4 males (19.1%) (p = 0.2).

CONCLUSION

Lipid levels and treatment were similar between sexes. MACE occurred in similar proportions between sexes, indicating that HoFH offsets the inherently lower cardiovascular risk in pre-menopausal females. Further investigation into sex-differences in HoFH in larger sample sizes is warranted.

High density lipoprotein infusion therapy: A review

Increased cholesterol-rich, low-density, non-calcified atheromas as assessed by computer coronary tomography angiography (CCTA) analyses have been shown to predict myocardial infarction significantly better than coronary artery calcium score or the presence of obstructive coronary artery disease (CAD) as evaluated with standard coronary angiography. Low serum high-density lipoprotein (HDL) cholesterol values are an independent risk factor for CAD. Very small, lipid-poor preβ-1 HDL particles have been shown to be most effective in promoting cellular cholesterol efflux. HDL infusions have been documented to reduce aortic atherosclerosis in cholesterol-fed animal models. However, human studies using infusions of either the HDL mimetic containing recombinant apolipoprotein (apo) A-I Milano or Cerenis Compound-001 with native recombinant apoA-I have been mainly negative in promoting coronary atherosclerosis progression as assessed by intravascular ultrasound. In contrast, a study using 7 weekly infusions of autologous delipidated HDL in six homozygous familial hypercholesterolemic patients was effective in promoting significant regression of low-density non-calcified coronary atheroma regression as assessed by computed coronary angiography. This therapy has received Food and Drug Administration approval. Commonwealth Serum Laboratories (CSL) has carried out a large clinical endpoint trial using an HDL complex (native apoA-I with phospholipid), and the results were negative. Our purpose is to review animal and human studies using various forms of HDL infusion therapy to promote regression of atherosclerosis. In our view, differences in results may be due to: 1) the HDL preparations used, 2) the subjects studied, and 3) the methods used to assess coronary atherosclerosis.

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.

Metabolic systems approaches update molecular insights of clinical phenotypes and cardiovascular risk in patients with homozygous familial hypercholesterolemia

BACKGROUND

Homozygous familial hypercholesterolemia (HoFH) is an orphan metabolic disease characterized by extremely elevated low-density lipoprotein cholesterol (LDL-C), xanthomas, aortic stenosis, and premature atherosclerotic cardiovascular disease (ASCVD). In addition to LDL-C, studies in experimental models and small clinical populations have suggested that other types of metabolic molecules might also be risk factors responsible for cardiovascular complications in HoFH, but definitive evidence from large-scale human studies is still lacking. Herein, we aimed to comprehensively characterize the metabolic features and risk factors of human HoFH by using metabolic systems strategies.

METHODS

Two independent multi-center cohorts with a total of 868 individuals were included in the cross-sectional study. First, comprehensive serum metabolome/lipidome-wide analyses were employed to identify the metabolomic patterns for differentiating HoFH patients (n = 184) from heterozygous FH (HeFH, n = 376) and non-FH (n = 100) subjects in the discovery cohort. Then, the metabolomic patterns were verified in the validation cohort with 48 HoFH patients, 110 HeFH patients, and 50 non-FH individuals. Subsequently, correlation/regression analyses were performed to investigate the associations of clinical/metabolic alterations with typical phenotypes of HoFH. In the prospective study, a total of 84 HoFH patients with available follow-up were enrolled from the discovery cohort. Targeted metabolomics, deep proteomics, and random forest approaches were performed to investigate the ASCVD-associated biomarkers in HoFH patients.

RESULTS

Beyond LDL-C, various bioactive metabolites in multiple pathways were discovered and validated for differentiating HoFH from HoFH and non-FH. Our results demonstrated that the inflammation and oxidative stress-related metabolites in the pathways of arachidonic acid and lipoprotein(a) metabolism were independently associated with the prevalence of corneal arcus, xanthomas, and supravalvular/valvular aortic stenosis in HoFH patients. Our results also identified a small marker panel consisting of high-density lipoprotein cholesterol, lipoprotein(a), apolipoprotein A1, and eight proinflammatory and proatherogenic metabolites in the pathways of arachidonic acid, phospholipid, carnitine, and sphingolipid metabolism that exhibited significant performances on predicting first ASCVD events in HoFH patients.

CONCLUSIONS

Our findings demonstrate that human HoFH is associated with a variety of metabolic abnormalities and is more complex than previously known. Furthermore, this study provides additional metabolic alterations that hold promise as residual risk factors in HoFH population.

Counseling couples at risk of having a child with homozygous familial hypercholesterolemia - Clinical experience and recommendations

Homozygous familial hypercholesterolemia (HoFH) is a rare, potentially life-limiting, inherited disorder of lipoprotein metabolism characterized by extremely high low-density lipoprotein cholesterol levels. When both parents have heterozygous FH, there is a 25% chance they will conceive a child with HoFH. Here we describe our clinical experience with two such prospective parent couples who were counseled regarding reproductive options and prenatal testing for HoFH. These cases showcase how, in consultation with a molecular geneticist and pediatric cardiologist, parents may be informed of the prognosis and treatment outlook of HoFH based on the FH-variants carried, to ultimately make personal decisions on reproductive options. One couple opted for prenatal testing and termination of pregnancy in case HoFH was found, while the other accepted the risk without testing. We review the available literature on preconception counseling for HoFH and provide practical guidance to clinicians counseling at-risk couples. Optimal counseling of prospective parents may help prevent future physical and psychological problems for both parent and child.

An update on lipid apheresis for familial hypercholesterolemia

Familial hypercholesterolemia (FH) is an inherited metabolic defect leading to increased total cholesterol and low-density cholesterol (LDL) from birth onwards. Homozygous FH, presenting with clear clinical features, has a prevalence of ~ 1 per million. Prevalence of heterozygous FH is 1/500 European population. Atherosclerotic burden depends on the degree and duration of high LDL exposure. In severe cases, early detection is critical, and aggressive lipid-lowering therapies should begin in early childhood to reduce coronary heart disease risk. Pediatric therapeutic concepts correspond to adults and are orientated at LDL plasma concentration. Mean LDL plasma target value during treatment is < 135 mg/dL. Medication in childhood consists of ezetemibe, statins, resins, and PCSK-9 inhibitors, with consideration for age restrictions. Only a minority achieve the treatment target with drug therapy alone. Therapeutic apheresis for the treatment of hypercholesterolemia selectively removes lipoproteins from blood (lipid apheresis (LA)). LA has a long tradition in adult medicine and is also safely used in children by a variety of methods, if customized to special pediatric needs. LA reduces cholesterol levels independently of residual LDL-receptor function and not only achieves reduction or disappearance of xanthomas but also inhibits progression of or mitigates aortic valve stenosis and supravalvular aortic stenosis as well as coronary artery and other atherosclerotic lesions. Cardiovascular prognosis of patients with otherwise untreatable FH depends largely on timely use of LA. Taking into account LA as a lifelong treatment, starting early in childhood, it is important to accommodate therapy modalities, such as treatment frequency and point of time, into the life of the individual.

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 PCSK9 inhibitor induces a transient decrease in the neutrophil-lymphocyte ratio and monocyte-lymphocyte ratio in homozygous familial hypercholesterolemia patients

Background and aims

Extremely elevated levels of low-density lipoprotein-cholesterol (LDL-C) contribute to long-term chronic systemic inflammation in homozygous familial hypercholesterolemia (HoFH) patients. The aims of this study is to describe the inflammatory profile of HoFH patients and explore the effect of a PCSK9 inhibitor (PCSK9i) on a series of inflammatory biomarkers, including the neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), monocyte-HDL ratio (MHR), monocyte-lymphocyte ratio (MLR) and mean platelet volume-lymphocyte ratio (MPVLR).

Methods

In this prospective cohort study, 25 definitive HoFH patients on high-intensity statins plus ezetimibe were administered subcutaneous injections of 420 mg PCSK9i every 4 weeks (Q4W). The biochemical parameters and inflammatory profile were analyzed on the day before PCSK9i therapy and 3 months and 6 months after PCSK9i therapy.

Results

HoFH on the maximum tolerated statin dose plus ezetimibe displayed elevated lipid and disturbed blood biomarker profiles. After 3 months of add-on PCSK9i therapy, a significant reduction in LDL-C was observed. Moreover, the percentage and count of neutrophils, monocyte counts, MPV, and two inflammatory biomarkers, the NLR and MLR, were reduced. However, at 6 months of PCSK9i treatment, the NLR and MLR returned to pre-PCSK9i treatment levels.

Conclusions

PCSK9i induces a transient decrease in the NLR and MLR in HoFH patients in a lipid-lowering independent manner.

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.

New Frontiers in the Treatment of Homozygous Familial Hypercholesterolemia

Homozygous familial hypercholesterolemia (HoFH) is a rare genetic disorder. The most common cause is a mutation in both alleles of the gene encoding for the low-density lipoprotein (LDL) receptor, although other causative mutations have been identified. Complications of atherosclerotic cardiovascular disease are common in these patients; therefore, reducing the elevated LDL-cholesterol burden is critical in their management. Conventionally, this is achieved by patients initiating lipid-lowering therapy, but this can present challenges in clinical practice. Fortunately, novel therapeutic strategies have enabled promising innovations in HoFH treatment. This review highlights recent and ongoing studies examining new therapeutic options for patients with HoFH.

Evolocumab in patients with homozygous familial hypercholesterolemia in India

BACKGROUND

Evolocumab is a fully human monoclonal antibody inhibitor of proprotein convertase subtilisin/kexin type 9 approved in India for treatment of homozygous familial hypercholesterolemia (HoFH) in patients aged ≥12 years.

OBJECTIVE

RAMAN (NCT03403374) was a single-country, open-label, phase 4 study evaluating the safety and tolerability of evolocumab in patients with HoFH in India.

METHODS

Patients ≥12 to ≤80 years of age on stable lipid-lowering therapy with fasting low-density lipoprotein cholesterol (LDL-C) >3.4 mmol/L (>130 mg/dL) received evolocumab 420 mg subcutaneously monthly (every 2 weeks if on apheresis). The primary endpoint was patient incidence of treatment-emergent adverse events. Secondary endpoints included percent changes at week 12 in LDL-C and other lipids.

RESULTS

Of 30 enrolled patients, 13 were <18 years of age. Mean±SD baseline levels of LDL-C, apolipoprotein B, and lipoprotein(a) were 12.3 ± 3.5 mmol/L (473.5 ± 135.2 mg/dL), 2.8 ± 0.7 g/L (275.3 ± 69.1 mg/dL), and 201.3 ± 177.6 nmol/L, respectively. Ten patients (33%) reported treatment-emergent adverse events, with 2 (7%) serious adverse events and none leading to discontinuation; no deaths occurred during evolocumab treatment. At week 12, mean (SE) percent changes from baseline in LDL-C, apolipoprotein B, and lipoprotein(a) were -6.4% (4.2), -6.0% (3.7), and -0.2% (4.9), respectively. Reductions in LDL-C among individual patients were variable and greatest in patients ≥18 years of age and with baseline LDL-C <13 mmol/L (<500 mg/dL).

CONCLUSIONS

Evolocumab was safe and well tolerated in patients with HoFH in India with smaller reductions in LDL-C and other lipids than those observed in previous studies with HoFH and different populations.

Situation in 2020 of the requirements for the use of PCSK9 inhibitors in Spain: Results of a national survey

AIMS

During 2019 and 2020 a series of meetings over the country were carried out, with the aim of explaining the methodology and criteria for the ellaboration of the recommendations on the use of iPCSK9, published by the Spanish Society of Atherosclerosis (SEA in Spanish). At the end of the meetings, a survey was conducted among the participants, in order to describe the prescription requirements of these drugs in the Spanish regions.

METHODOLOGY

Butterfly Project was developed by a scientific Committee of experts in lipids. After the ellaboration of the materials for the project, a train the trainers program was carried out, imparted by 17 experts who were the Project coordinators. Later, 16 regional workshops were performed, with the attendance of 169 medical doctors involved in the management of hipercolesterolemia. The attendants responded the survey, where they were asked different questions on the use of iPCSK9 on their clinical practice.

RESULTS

A high heterogeneity among centers regarding the requirements and difficulties for iPCSK9 prescription was revealed. Twenty one per cent of responders indicated to have low difficulties to prescribe iPCSK9 in their hospitals, whereas 78% found moderate or high difficulties. The difficulties came from burocracy- administrative aspects (18%), restrictions in the indication (41%) and both (38%). In general, the obstacles did not depend on the hospital level, neither the speciality, or the presence of lipid units, although the existance of lipid units was associated with a higher number of patients treated with iPCSK9. The factors which were associated with higher difficulty in the prescription were: the presence of an approval committee in the hospitals, the frequency in the revision of the treatment by hospital pharmacy, the temporal cadence of the prescription, the profile of patients seen and the criteria followed by the specialists for the prescription.

CONCLUSION

The results show important diferences in the treatment with iPCSK9 in the context of clinical practice in Spain. The analysis of these results will permit to make proposals regarding future actions addressed to reach the equity in the access to iPCSK9 in Spain, with the main aim of maximizing their potential benefit according to the patients profile.

Rare Treatments for Rare Dyslipidemias: New Perspectives in the Treatment of Homozygous Familial Hypercholesterolemia (HoFH) and Familial Chylomicronemia Syndrome (FCS)

Purpose of Review

This review aims to summarize the most recent published literature concerning lomitapide and volanesorsen that are approved for the use in HoFH and FCS patients, respectively. Moreover, it will briefly revise the published evidence on novel, non-approved treatments that are under evaluation for the management of these rare forms of dyslipidemias

Recent Findings

The definition of rare dyslipidemias identifies a large number of severe disorders of lipid metabolism of genetic origin. Among them were homozygous familial hypercholesterolemia (HoFH) (OMIM #143890) and familial chylomicronemia syndrome (FCS) (OMIM #238600), which are characterized by a markedly impaired cholesterol- and triglyceride-containing lipoproteins metabolism. They are being particularly associated with poor health outcomes and quality of life. Considering the severity of these diseases, common lipid-lowering drugs are often ineffective or do not allow to achieve the recommended lipid targets to prevent the development of complications. Nowadays, several new drugs have been found to effectively treat HoFH and FCS with an acceptable safety profile.

Summary

Treating patients with HoFH and FCS remains very challenging. However, novel treatment options are emerging and might be considered in addition to conventional therapy for managing these diseases. These novel drugs will possibly change the natural history of these two rare and life-threatening diseases.

Integrated analysis of microRNA and mRNA expression profiles in homozygous familial hypercholesterolemia patients and validation of atherosclerosis associated critical regulatory network

Homozygous familial hypercholesterolemia (HoFH) is a rare, life-threatening genetic disorder characterized by an extremely elevated serum level of low-density lipoprotein cholesterol (LDL-C) and accelerated premature atherosclerotic cardiovascular diseases (ASCVD). However, the detailed mechanism of how the pathogenic mutations of HoFH trigger the acceleration of ASCVD is not well understood. Therefore, we performed high-throughput RNA and small RNA sequencing on the peripheral blood RNA samples of six HoFH patients and three healthy controls. The gene and miRNA expression differences were analyzed, and seven miRNAs and six corresponding genes were screened out through regulatory network analysis. Validation through quantitative PCR of genes and miRNAs from 52 HoFH patients and 20 healthy controls revealed that the expression levels of hsa-miR-486-3p, hsa-miR-941, and BIRC5 were significantly upregulated in HoFH, while ID1, PLA2G4C, and CACNA2D2 were downregulated. Spearman correlation analysis found that the levels of ID1, hsa-miR-941, and hsa-miR-486-3p were significantly correlated with additional ASCVD risk factors in HoFH patients. This study represents the first integrated analysis of transcriptome and miRNA expression profiles in patients with HoFH, a rare disease, and as a result, six differentially expressed miRNAs/genes that may be related to atherosclerosis in HoFH are reported. The miRNA-mRNA regulatory network may be the critical regulation mechanism by which ASCVD is accelerated in HoFH.

Marked plaque regression in homozygous familial hypercholesterolemia

BACKGROUND AND AIMS

Both plasma low-density lipoprotein (LDL) cholesterol levels and risk for premature cardiovascular disease are extremely elevated in patients with homozygous familial hypercholesterolemia (HoFH), despite the use of multiple cholesterol lowering treatments. Given its inborn nature, atherosclerotic plaques are commonly observed in young HoFH patients. Whether intensive lipid lowering strategies result in plaque regression in adolescent patients is unknown.

METHODS

Two HoFH patients with null/null LDLR variants, who participated in the R1500-CL-1629 randomized clinical trial (NCT03399786) evaluating the LDL cholesterol lowering effect of evinacumab (a human antibody directed against ANGPTL3; 15 mg/kg intravenously once monthly), were included in this study. Patients underwent coronary computed tomography angiography (CCTA) before randomization and after 6 months of treatment.

RESULTS

Both patient A (aged 12) and B (aged 16) were treated with a statin, ezetimibe and weekly apheresis. Evinacumab decreased mean pre-apheresis LDL cholesterol levels from 5.51 ± 0.75 and 5.07 ± 1.45 mmol/l to 2.48 ± 0.31 and 2.20 ± 0.13 mmol/l and post-apheresis LDL levels from 1.45 ± 0.26 and 1.37 ± 39 mmol/l to 0.80 ± 0.16 and 0.78 ± 0.13 mmol/l in patient A and B, respectively. Total plaque volumes were reduced by 76% and 85% after 6 months of evinacumab treatment in patient A and B, respectively.

CONCLUSIONS

We describe two severely affected young HoFH patients in whom profound plaque reduction was observed with CCTA after intensive lipid lowering therapy with statins, ezetimibe, LDL apheresis, and evinacumab. This shows that atherosclerotic plaques possess the ability to regress at young age, even in HoFH patients.

Homozygous Familial Hypercholesterolemia (HoFH) in Saudi Arabia and Two Cases of Lomitapide Use in a Real-World Setting

Introduction

Homozygous familial hypercholesterolemia (HoFH) is a rare, genetic condition in which mutations in key peptides involved in the low-density lipoprotein receptor (LDL-R) pathway result in markedly elevated levels of circulating LDL-cholesterol (LDL-C). Patients are at high risk of developing early-onset atherosclerotic cardiovascular disease with associated mortality risks. Treatment options are extremely limited, and aspects of society and medical care in Saudi Arabia have the potential to increase incidence and limit treatment pathways in HoFH.

Methods

Along with a brief review of the evidence available on HoFH we describe the treatment of two Saudi Arabian patients with HoFH diagnosed and treated in accordance with local clinical practices and with the microsomal triglyceride transferase protein inhibitor lomitapide.

Results

HoFH in Saudi Arabia is characterized by problems associated with consanguinity, a lack of access to lipoprotein apheresis, and pressures to proceed to liver transplant. Among the case histories, the first patient was commenced on lomitapide therapy, and underwent a dramatic decrease in LDL-C levels from 16.5 to 2.2 mmol/L (87% decrease). This patient had problems with access to lomitapide and cessation of the drug resulted in rebound in LDL-C to 22 mmol/L. The second patient experienced delayed commencement of lomitapide therapy. Despite a 45% decrease in LDL-C levels from 15.3 to 6.9 mmol/L, the patient died the following year at age 26 years from complications subsequent to cardiovascular surgery. Lomitapide was well tolerated in both patients

Discussion

The experience of these two cases highlights the need for prompt, effective, and sustained intervention in HoFH to prevent cardiovascular morbidity and mortality. Lomitapide is an effective therapy for HoFH, and we look forward to improved access to this drug in Saudi Arabia, where there is a chronic unmet medical need in HoFH.

A case of homozygous familial hypercholesterolemia with an atypical phenotype and delayed clinical symptoms

We describe the casuistry of a homozygous familial hypercholesterolemia female patient with a biallelic missense variant (NM_000527.4:c.1775G>A, p.Gly592Glu) in the LDLR gene, severe hypertriglyceridemia and late manifestation of coronary heart disease not earlier than at the age of 45 years. An atypical phenotype led to a delayed diagnosis.

Homozygous Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is an inherited disorder with retarded clearance of plasma LDL caused by mutations of the genes involved in the LDL receptor-mediated pathway and most of them exhibit autosomal dominant inheritance. Homozygotes of FH (HoFH) may have plasma LDL-C levels, which are at least twice as high as those of heterozygous FH (HeFH) and therefore four times higher than normal levels. Prevalence of HoFH had been estimated as 1 in 1,000,000 before but more recent genetic analysis surveys predict 1 in 170,000 to 300,000. Since LDL receptor activity is severely impaired, HoFH patients do not or very poorly respond to medications to enhance activity, such as statins, and have a poorer prognosis compared to HeFH. HoFH should therefore be clinically distinguished from HeFH. Thorough family studies and genetic analysis are recommended for their accurate diagnosis.

Fatal cardiovascular complications could develop even in the first decade of life for HoFH, so aggressive lipid-lowering therapy should be initiated as early as possible. Direct removal of plasma LDL by lipoprotein apheresis has been the principal measure for these patients. However, this treatment alone may not achieve stable LDL-C target levels and combination with drugs should be considered. The lipid-lowering effects of statins and PCSK9 inhibitors substantially vary depending on the remaining LDL receptor activity of individual patients. On the other hand, the action an MTP inhibitor is independent of LDL receptor activity, and it is effective in most HoFH cases.

This review summarizes the key clinical issues of HoFH as well as insurance coverage available under the Japanese public healthcare system.

Development of Antisense Oligonucleotide Gapmers for the Treatment of Dyslipidemia and Lipodystrophy

Although technological advances in molecular genetics over the last few decades have greatly expedited the identification of mutations in many genetic diseases, the translation of the genetic mechanisms into a clinical setting has been quite challenging, with a minimum number of effective treatments available. The advancements in antisense therapy have revolutionized the field of neuromuscular disorders as well as lipid-mediated diseases. With the approval of splice-switching antisense oligonucleotide (AO) therapy for nusinersen and eteplirsen for the treatment of spinal muscular atrophy (SMA) and Duchenne muscular dystrophy (DMD), several modified AOs are now being evaluated in clinical trials for the treatment of a number of disorders. In order to activate RNase H-mediated cleavage of the target mRNA, as well as to increase the binding affinity and specificity, gapmer AOs are designed that have a PS backbone flanked with the modified AOs on both sides. Mipomersen (trade name Kynamro), a 2'-O-methoxyethyl (MOE) gapmer, was approved by the Food and Drug Administration (FDA) for the treatment of homozygous familial hypercholesterolemia (HoFH) in 2013. Volanesorsen, another 20-mer MOE gapmer has shown to be successful in lowering the levels of triglycerides (TGs) in several lipid disorders and has received conditional approval in the European Union for the treatment of Familial chylomicronemia syndrome (FCS) in May 2019 following successful results from phase II/III clinical trials. This chapter focuses on the clinical applications of gapmer AOs for genetic dyslipidemia and lipodystrophy.

A randomized study investigating the safety, tolerability, and pharmacokinetics of evinacumab, an ANGPTL3 inhibitor, in healthy Japanese and Caucasian subjects

BACKGROUND AND AIMS

Evinacumab, an angiopoietin-like protein 3 monoclonal antibody, reduced low-density lipoprotein cholesterol (LDL-C) significantly in a Phase 2 study of patients with homozygous familial hypercholesterolemia. In this double-blind, placebo-controlled Phase 1 study, we compared safety, tolerability, pharmacokinetics, and pharmacodynamics of evinacumab between healthy Japanese and Caucasian adults.

METHODS

Subjects with LDL-C ≥2.6 and <4.1 mmol/L were enrolled to one of four dose cohorts: evinacumab subcutaneous (SC) 300 mg single dose, SC 300 mg once weekly for eight doses, intravenous (IV) 5 mg/kg, or IV 15 mg/kg once every 4 weeks for two doses. Each cohort comprised 24 subjects (12 Japanese; 12 Caucasian), randomized (3:1) to receive evinacumab or placebo within each ethnic group with a 24-week follow-up.

RESULTS

The safety profile of evinacumab (IV and SC) in both ethnicities was comparable with placebo, with no serious or severe treatment-emergent adverse events. Pharmacokinetic profiles were comparable between Japanese and Caucasian subjects across IV and SC groups. Mean calculated LDL-C decreased from baseline with both IV doses, beginning on day 3 up to week 8. Triglyceride changes observed with evinacumab IV were rapid (seen by day 2) and sustained up to week 8. Evinacumab SC doses also reduced LDL-C and triglyceride levels, although lower doses induced smaller changes. Evinacumab (IV and SC) reduced other lipids, including apolipoprotein B, versus placebo.

CONCLUSIONS

In both ethnicities, evinacumab (IV and SC) was generally well tolerated, exhibiting comparable pharmacokinetic profiles. Dose-related reductions in LDL-C and triglycerides were observed with evinacumab in both ethnic groups.

Successful pharmacological management of a child with compound heterozygous familial hypercholesterolemia and review of the recent literature

Severe familial hypercholesterolemia (SFH) is characterized by markedly elevated low-density lipoprotein cholesterol (LDL-C) and severe early-onset cardiovascular disease if left untreated. We report on the decade-long therapeutic journey of a 15-year-old boy with SFH due to a severe compound heterozygous genotype. He presented at the age of 5 years with widespread xanthomas and LDL-C of 17.4 mmol/L. He was diagnosed with SFH, initially treated with colestyramine that was subsequently combined with simvastatin. At the age of 12 years, he was diagnosed to have supravalvular aortic stenosis and ezetimibe/atorvastatin was introduced in place of colestyramine/simvastatin. At the age of 14 years, he received triple therapy with evolocumab, initially at the recommended dose of 420 mg monthly and then reduced to 140 mg biweekly. Currently at the age of 15 years, he is on atorvastatin 40 mg ON, ezetimibe 10 mg OM, and evolocumab 140 mg biweekly, achieving LDL-C levels of 2.4 mmol/L. Genetic testing identified compound heterozygous mutations in the LDL receptor genes [c.(940 + 1_941-1) (1845 + 1_1846-1)dup] and exon 12, nucleotide c.1747 C > T, amino acid p.(His583Tyr). Medical management without lipoprotein apheresis can achieve target LDL-C in children with SFH. Our patient, who developed supravalvular aortic stenosis at the age of 12 years, needed early aggressive treatment when SFH guidelines and newer drugs for young children were unavailable. Our patient demonstrated that 140 mg biweekly of evolocumab has the same cholesterol-lowering effect as the recommended 420 mg monthly dose.

Lomitapide for treatment of homozygous familial hypercholesterolemia: The Québec experience

BACKGROUND AND AIMS

Homozygous familial hypercholesterolemia (HoFH) is an orphan disease, most often caused by bi-allelic mutations of the LDLR gene. Patients with HoFH have elevated LDL-C levels >13 mmol/L, tendinous xanthomata and severe, premature atherosclerotic cardiovascular disease (ASCVD). Untreated, most HoFH patients die of ASCVD in youth. New therapeutic modalities include lomitapide, an inhibitor of microsomal triglyceride transfer protein that lowers hepatic LDL-C production. We have recently identified 79 Canadian patients with HoFH. Here, we describe our experience with lomitapide in the province of Quebec, a geographic area known to have a high prevalence of HoFH.

METHODS

This is a retrospective case series of 12 HoFH patients followed at three lipidology centers in the province of Quebec.

RESULTS

Mean age of the patients was 44 ± 18 years; age at time of HoFH diagnosis ranged from 2 to 59 years. All patients were on a statin and ezetimibe 10 mg/day and five patients were treated with LDL apheresis. Treatment with lomitapide reduced LDL-C levels by 38% (intention-to-treat). Intolerable gastrointestinal side effects were observed in 3/12 patients and were the main reason for treatment discontinuation. Three patients tolerated lomitapide at doses ranging between 5 and 30 mg/day without major side effects. Downwards drug titration was necessary in the 6 remaining patients because of gastrointestinal side effects (n = 5) and elevated liver enzymes (n = 1), and 2 of them finally discontinued treatment.

CONCLUSIONS

Lomitapide may be used to further decrease LDL-C in HoFH patients; gastrointestinal side effects and hepatic toxicity may limit adherence.

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.

Mental status and physical activity in patients with homozygous familial hypercholesterolemia: A subgroup analysis of a nationwide survey (A-HIT1 registry)

BACKGROUND

Homozygous familial hypercholesterolemia (HoFH) is a rare, life-threatening disease due to high serum low-density lipoprotein (LDL) cholesterol levels. LDL cholesterol-lowering interventions are fundamental for patients with HoFH.

OBJECTIVE

It was aimed to investigate the association between the mental status of patients with HoFH and healthy lifestyle behaviors.

METHODS

This subgroup analysis of the A-HIT1 population included the data of patients aged ≥18 years with a clinical diagnosis of HoFH undergoing therapeutic LDL apheresis. Besides the demographic and clinical characteristics of patients, healthy lifestyle behaviors were assessed, and psychiatric symptoms were screened by Symptom Check List (SCL-90-R).

RESULTS

The highest percentage for pathology was observed in dimensions of obsessive-compulsive, somatization, interpersonal sensitivity, and depression in SCL-90-R. Patients with any cardiovascular condition have more psychiatric symptoms in different fields of SCL-90-R. The outcomes of the correlative analysis indicated that lower the age of the first coronary event better the psychiatric status, probably denoting a better adaptation to disease and its treatment. Among 68 patients, 36 patients were not exercising regularly. Patients with regular physical activity had significantly lower scores in most dimensions of SCL-90-R and there was no association between regular physical activity and other investigated variables. The strongest predictor of regular exercising was global severity index of SCL-90-R.

CONCLUSION

In the HoFH population, there was a high prevalence of mental disturbances. Better psychiatric status was associated with regular exercising. Therefore, assessing the mental status of patients with HoFH and referring patients in need, to a psychiatrist, may improve the outcome of patients.

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.

Homozygous familial hypercholesterolaemia in childhood - The first case report in Southeast Europe

Homozygous familial hypercholesterolaemia (HoFH) is the rare, severe, but treatable disease characterised by exceedingly high levels of low-density lipoprotein cholesterol (LDL-C) and subsequent premature coronary heart disease. Of note, HoFH detection rate and patient access to healthcare and treatment modalities still differ considerably across EU countries. To our current knowledge, there are still no published reports describing HoFH in the paediatric population of Southeastern Europe. In this case report, a few important topics on obstacles in getting adequate health care service and management of HoFH children from Southeastern Europe are tackled.

Case report: The efficacy and safety of lomitapide in a homozygous familial hypercholesterolemic child

We report for the first time the efficiency and safety of a 49-month compassionate use of the microsomal transfer protein inhibitor lomitapide in a child with homozygous familial hypercholesterolemia. On average, 20 mg of lomitapide caused a 37% reduction in low-density lipoprotein cholesterol levels on top of ezetimibe and atorvastatin. The drug was well tolerated with no changes in liver enzymes and occurrence of steatosis on hepatic ultrasound. The patient presented adequate growth and sexual maturation. Nonetheless, there was progression in either subclinical atherosclerotic carotid or aortic valve diseases. Further studies are necessary to test the impact and safety of lomitapide in children with homozygous familial hypercholesterolemia.

Dietary Intake during 56 Weeks of a Low-Fat Diet for Lomitapide Treatment in Japanese Patients with Homozygous Familial Hypercholesterolemia

AIM

Lomitapide is an oral inhibitor of the microsomal triglyceride transfer protein used to treat homozygous familial hypercholesterolemia (HoFH); patients require a low-fat diet to minimize gastrointestinal adverse effects and dietary supplements to prevent nutrient deficiencies. We investigated the diet and nutritional status during lomitapide treatment.

METHODS

Japanese patients with HoFH, who were in a phase 3 trial of lomitapide, were instructed to start low-fat diets with supplements of vitamin E and essential fatty acids 6 weeks before starting lomitapide treatment. Dietary education was conducted by registered dietitians 16 times during the study period, which included a pre-treatment run-in phase (Weeks －6-0), a lomitapide treatment efficacy phase (Weeks 0-26) and a safety phase (Weeks 26-56). Two-day dietary records were collected at each dietary counseling session. Anthropometric and biochemical parameters were measured at Weeks 0, 26 and 56.

RESULTS

Eight patients completed the 56 weeks of lomitapide treatment. Their median energy intakes derived from lipids were 19.2% and 17.9% during the efficacy and safety phases, respectively. "Fats and oils" intakes, and "Fatty meat and poultry" intakes in two patients, were successfully reduced to achieve low-fat diets. Although intakes of energy, fatty acids and fat-soluble vitamins did not differ significantly among phases, body weight, serum fatty acid levels and vitamin E concentrations were decreased at Week 26 as compared with Week 0.

CONCLUSION

HoFH patients can adhere to low-fat diets with ongoing dietary counseling. Instructions about intakes of energy, fatty acids and fat-soluble vitamins, as well as periodic evaluations of nutritional status, are necessary.

Safety and Efficacy of Lomitapide in Japanese Patients with Homozygous Familial Hypercholesterolemia (HoFH): Results from the AEGR-733-301 Long-Term Extension Study

Aim: Lomitapide is an approved lipid-lowering agent indicated as adjunct to low-fat diet and standard lipid-lowering therapies (LLTs) including lipoprotein apheresis for the treatment of homozygous familial hypercholesterolemia (HoFH). Clinical data from Phase 3 studies have demonstrated the prolonged lipid-lowering capacity of lomitapide in patients with HoFH. We assessed the long-term lipid-lowering capacity of daily oral lomitapide in a cohort of Japanese patients with HoFH enrolled in a Phase 3 extension study.

Methods: Five of 8 Japanese HoFH patients completing a 56-week Phase 3 dose-escalation and safety study of lomitapide continued their maximum tolerated dose (MTD) until study drug was approved or commercially available or until treatment was discontinued. Lipid parameters were measured at Day 1 and at 12-week intervals through study end. Safety and tolerability were assessed.

Results: Daily lomitapide treatment with permitted LLTs maintained approximately 50% mean reductions in plasma low-density lipoprotein cholesterol (LDL-C) levels from baseline for > 60 weeks. Reductions in LDL-C levels varied across patients and were not associated with the HoFH genotype. Four patients achieved > 25% reductions and 1 patient achieved > 50% reduction in LDL-C; 2 patients achieved reduction in LDL-C to < 100 mg/dL. Lomitapide significantly reduced total cholesterol (−26.5%), triglycerides (−54.8%), and non-highdensity lipoprotein cholesterol (non-HDL-C) (−37.4%). All 5 patients continued their individual MTD of lomitapide throughout the extension study with acceptable safety and tolerability, and no deaths were reported.

Conclusions: Results from this extension study support the long-term safety and efficacy of lomitapide in significantly reducing plasma levels of atherosclerotic lipids in patients with HoFH.

High serum triglyceride concentrations in patients with homozygous familial hypercholesterolemia attenuate the efficacy of lipoprotein apheresis by dextran sulfate adsorption

BACKGROUND AND AIMS

Maximizing the acute reduction of LDL-cholesterol (C) and lipoprotein (a) (Lp(a)) concentrations in patients with homozygous familial hypercholesterolemia (HoFH) is the main goal of lipoprotein apheresis (LA). The objective of this study was to examine how the pre-LA serum TG concentrations influence the efficacy of LA to acutely reduce LDL-C and Lp(a) concentrations in HoFH patients.

METHODS

Data from 1761 LA treatments of HoFH patients (n = 10) and compound heterozygous patients (n = 5) collected between 2008 and 2016 were analyzed. These data included the pre- and post-LA concentrations of LDL-C, TGs and Lp(a); volume of filtered plasma; type of LA system used (dextran sulfate adsorption (DSA) or heparin-induced extracorporeal LDL precipitation (HELP)); and interval between treatments.

RESULTS

A significant association between the pre-LA TG concentrations and acute LA-induced reduction in LDL-C, modified by the type of LA system used, was observed (p_{pre-LA TG quartile*LA system} = .04). Using the DSA system, the acute reduction of the LDL-C concentrations was attenuated by 3.9% when the pre-LA TG concentrations were >2.09 mmol/L vs. ≤0.93 mmol/L (highest vs. lowest quartiles: -59.4% vs. -63.3%, p = .007). Using the HELP system, no significant difference was observed in the reduction of LDL-C between the highest and the lowest quartiles of serum TGs (-65.8% vs. -66.4%, p = .9). No association was observed between pre-LA TG concentrations and acute LA-induced decrease in Lp(a) (p = .2).

CONCLUSIONS

The efficacy of LA is inversely associated with pre-LA TG concentrations in HoFH patients who used the DSA system instead of the HELP system.

Rapidly progressive atherosclerosis after domino liver transplantation from a teenage donor with homozygous familial hypercholesterolemia

Familial hypercholesterolemia (FH) is an autosomal dominant disorder characterized by impaired clearance of low-density lipoprotein cholesterol. Given limitations in pharmacologic therapy and the significant morbidity and mortality associated with this disease, liver transplantation may be offered to select homozygous FH patients in childhood in an effort to slow progression of atherosclerotic cardiovascular disease. In rare cases, domino liver transplantation can be performed, transplanting the livers of patients with various metabolic disorders into elderly recipients whose projected survival precludes prolonged waiting on the transplant list. Herein, we report a case of domino liver transplantation using the liver of a 14-year-old boy with homozygous FH into a 65-year-old man with primary sclerosing cholangitis and cirrhosis who developed rapidly progressive atherosclerotic cardiovascular disease involving the arteries of his proximal bilateral lower extremities, carotid arteries and superior mesenteric artery.

Low-density lipoprotein receptor-negative compound heterozygous familial hypercholesterolemia: Two lifetime journeys of lipid-lowering therapy

We present the case history of 2 patients with low-density lipoprotein receptor-negative compound heterozygous familial hypercholesterolemia who did not receive lipoprotein apheresis. We describe the subsequent effect of all lipid-lowering medications during their life course including resins, statins, ezetimibe, nicotinic acid/laropiprant, mipomersen, and lomitapide. These cases tell the story of siblings affected with this rare disease, who are free of symptoms but still are at a very high cardiovascular disease risk, and their treatment from childhood.

Recent Developments in Gene Therapy for Homozygous Familial Hypercholesterolemia

Homozygous familial hypercholesterolemia (HoFH) is a life-threatening Mendelian disorder with a mean life expectancy of 33 years despite maximally tolerated standard lipid-lowering therapies. This disease is an ideal candidate for gene therapy, and in the last few years, a number of exciting developments have brought this approach closer to the clinic than ever before. In this review, we discuss in detail the most advanced of these developments, a recombinant adeno-associated virus (AAV) vector carrying a low-density lipoprotein receptor (LDLR) transgene which has recently entered phase 1/2a testing. We also review ongoing development of approaches to enhance transgene expression, improve the efficiency of hepatocyte transduction, and minimize the AAV capsid-specific adaptive immune response. We include a summary of key gene therapy approaches for HoFH in pre-clinical development, including RNA silencing of the gene encoding HMG-CoA reductase (HMGCR) and induced pluripotent stem cell transplant therapy.

Retrospective analysis of cohort database: Phenotypic variability in a large dataset of patients confirmed to have homozygous familial hypercholesterolemia

These data describe the phenotypic variability in a large cohort of patients confirmed to have homozygous familial hypercholesterolemia. Herein, we describe the observed relationship of treated low-density lipoprotein cholesterol with age. We also overlay the low-density lipoprotein receptor gene (LDLR) functional status with these phenotypic data. A full description of these data is available in our recent study published in Atherosclerosis, “Phenotype Diversity Among Patients With Homozygous Familial Hypercholesterolemia: A Cohort Study” (Raal et al., 2016) [1].

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.

Homozygous familial hypercholesterolemia: the c.1055G>A mutation in the LDLR gene and clinical heterogeneity

Familial hypercholesterolemia (FH) is a world public health issue because of its high frequency, morbidity, and mortality. FH is characterized by elevated plasma low-density lipoprotein cholesterol (LDL-C) levels and a high risk for premature cardiovascular disease. We report an 8-year-old male with homozygous familial hypercholesterolemia. The clinical and biochemical characteristics of this case were bilateral corneal arcus, xanthomas in several body parts, severe stenosis of the left carotid artery and serum total cholesterol levels of 782.0 mg/dL and 715.0 mg/dL LDL-C. The initial treatment was atorvastatin (40 mg) and ezetimibe (20 mg), with no satisfactory response. LDLR gene was analyzed and homozygosity for c.1055G>A mutation was observed, resulting in an amino acid change from cysteine to tyrosine in codon 352 (p.Cys352Tyr). This mutation is known as Mexico 2 and has only been observed in the Mexican population. Both parents and siblings were carriers of the same mutation, but the paternal grandmother and the father of the index case showed the phenomenon of incomplete penetrance. With the analysis 5 polymorphisms (rs1003723C>T, rs5930A>G, rs688C>T, rs5929T>C and rs5927A>G), a common ancestor for the mutation can be suggested and linkage to TGTCG haplotype.

[Diagnosis and treatment of familial hypercholesterolemia in Spain: consensus document]

La hipercolesterolemia familiar (HF) es un trastorno genético frecuente que se manifiesta desde el nacimiento y que causa un aumento en los niveles plasmáticos de colesterol-LDL (cLDL), xantomas y enfermedad coronaria prematura. Su detección y tratamiento precoz reduce la morbimortalidad coronaria. A pesar de la disponibilidad de un tratamiento eficaz, la HF está poco diagnosticada y tratada. La identificación de los casos índices y la posterior detección en cascada familiar utilizando los niveles de cLDL y la detección genética es la estrategia más coste-efectiva para la detección de nuevos casos. El tratamiento crónico con estatinas ha disminuido el riesgo cardiovascular a los niveles de la población general. Los objetivos en cLDL son < 130 mg/dl en los niños y adultos jóvenes, < 100 mg/dl en los adultos y < 70 mg/dl en los adultos con enfermedad coronaria conocida o diabetes. En la mayoría de los pacientes es difícil conseguir estos objetivos, por lo que puede ser necesario el tratamiento combinado con ezetimiba u otros fármacos. Cuando no se alcanzan los objetivos con el máximo tratamiento farmacológico tolerado, una reducción de cLDL ≥ 50% puede ser aceptable. La LDL-aféresis es útil en los pacientes homocigotos y en los heterocigotos graves resistentes al tratamiento. Este documento proporciona recomendaciones para el diagnóstico, cribado y tratamiento de la HF en niños y adultos, así como consejos específicos para los especialistas clínicos y médicos de atención primaria con el objetivo de mejorar el cuidado de los pacientes y reducir su carga de enfermedad cardiovascular.

Surgical treatment of valvular and supravalvular aortic stenosis in homozygous familial hypercholesterolemia

A 61-year-old male with homozygous familial hypercholesterolemia presented with dyspnea and syncope. He had been treated with low-density lipoprotein apheresis for 26 years. Echocardiography and computed tomography showed severe valvular and supravalvular aortic stenosis. Computed tomography and cardiac catheterization revealed a severely calcified narrowed aortic root and an occlusion in the proximal right coronary artery. During surgery, the ascending aorta was replaced under deep hypothermic circulatory arrest without aortic cross-clamping. After that, the aortic root from the annulus to the sino-tubular junction was enlarged with a two-ply bovine pericardial patch. An aortic valve replacement with a 17 mm mechanical valve and coronary artery bypass grafting to the right coronary artery were performed. The patient recovered from the surgery without any cerebrovascular complications.