Novel Therapies for Lipoprotein(a): Update in Cardiovascular Risk Estimation and Treatment.

PURPOSE OF REVIEW: Lipoprotein(a) is an important causal risk factor for cardiovascular disease but currently no available medication effectively reduces lipoprotein(a). This review discusses recent findings regarding lipoprotein(a) as a causal risk factor and therapeutic target in cardiovascular disease, it reviews current clinical recommendations, and summarizes new lipoprotein(a) lowering drugs. RECENT FINDINGS: Epidemiological and genetic studies have established lipoprotein(a) as a causal risk factor for cardiovascular disease and mortality. Guidelines worldwide now recommend lipoprotein(a) to be measured once in a lifetime, to offer patients with high lipoprotein(a) lifestyle advise and initiate other cardiovascular medications. Clinical trials including antisense oligonucleotides, small interfering RNAs, and an oral lipoprotein(a) inhibitor have shown great effect on lowering lipoprotein(a) with reductions up to 106%, without any major adverse effects. Recent clinical phase 1 and 2 trials show encouraging results and ongoing phase 3 trials will hopefully result in the introduction of specific lipoprotein(a) lowering drugs to lower the risk of cardiovascular disease.

A Review of the Clinical Pharmacology of Pelacarsen: A Lipoprotein(a)-Lowering Agent.

Patients with genetically associated elevated lipoprotein(a) [Lp(a)] levels are at greater risk for coronary artery disease, heart attack, stroke, and peripheral arterial disease. To date, there are no US FDA-approved drug therapies that are designed to target Lp(a) with the goal of lowering the Lp(a) level in patients who have increased risk. The American College of Cardiology (ACC) has provided guidelines on how to use traditional lipid profiles to assess the risk of atherosclerotic cardiovascular disease (ASCVD); however, even with the emergence of statin add-on therapies such as ezetimibe and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, some populations with elevated Lp(a) biomarkers remain at an increased risk for cardiovascular (CV) disease. Residual CV risk has led researchers to inquire about how lowering Lp(a) can be used as a potential preventative therapy in reducing CV events. This review aims to present and discuss the current clinical and scientific evidence pertaining to pelacarsen.

Personalized medicine in lipid-modifying therapy.

The choice of lipid-modifying treatment is largely based on the absolute level of cardiovascular risk and baseline lipid profile. Statins are the first-line treatment for most patients requiring reduction of low-density-lipoprotein cholesterol (LDL-C) and ezetimibe and proprotein convertase subtilisin/kexin type 9 inhibitors can be added to reach LDL-C targets. Statins have some adverse effects that are somewhat predictable based on phenotypic and genetic factors. Fibrates or omega-3 fatty acids can be added if triglyceride levels remain elevated. The RNA-targeted therapeutics in development offer the possibility of selective liver targeting for specific lipoproteins such as lipoprotein(a) and long-term reduction of LDL-C with infrequent administration of a small-interfering RNA may help to overcome the problem of adherence to therapy.

Lipoprotein(a) in atherosclerosis: from pathophysiology to clinical relevance and treatment options.

Lipoprotein(a) (Lp(a)) was discovered more than 50 years ago, and a decade later, it was recognized as a risk factor for coronary artery disease. However, it has gained importance only in the past 10 years, with emergence of drugs that can effectively decrease its levels. Lp(a) is a low-density lipoprotein (LDL) with an added apolipoprotein(a) attached to the apolipoprotein B component via a disulphide bond. Circulating levels of Lp(a) are mainly genetically determined. Lp(a) has many functions, which include proatherosclerotic, prothrombotic and pro-inflammatory roles. Here, we review recent data on the role of Lp(a) in the atherosclerotic process, and treatment options for patients with cardiovascular diseases. Currently 'Proprotein convertase subtilisin/kexin type 9' (PCSK9) inhibitors that act through non-specific reduction of Lp(a) are the only drugs that have shown effectiveness in clinical trials, to provide reductions in cardiovascular morbidity and mortality. The effects of PCSK9 inhibitors are not purely through Lp(a) reduction, but also through LDL cholesterol reduction. Finally, we discuss new drugs on the horizon, and gene-based therapies that affect transcription and translation of apolipoprotein(a) mRNA. Clinical trials in patients with high Lp(a) and low LDL cholesterol might tell us whether Lp(a) lowering per se decreases cardiovascular morbidity and mortality.KEY MESSAGESLipoprotein(a) is an important risk factor in patients with cardiovascular diseases.Lipoprotein(a) has many functions, which include proatherosclerotic, prothrombotic and pro-inflammatory roles.Treatment options to lower lipoprotein(a) levels are currently scarce, but new drugs are on the horizon.

Lipoprotein(a)-Lowering by 50 mg/dL (105 nmol/L) May Be Needed to Reduce Cardiovascular Disease 20% in Secondary Prevention: A Population-Based Study.

OBJECTIVE: High Lp(a) (lipoprotein[a]) cause cardiovascular disease (CVD) in a primary prevention setting; however, it is debated whether high Lp(a) lead to recurrent CVD events. We tested the latter hypothesis and estimated the Lp(a)-lowering needed for 5 years to reduce CVD events in a secondary prevention setting. Approach and Results: From the CGPS (Copenhagen General Population Study; 2003-2015) of 58 527 individuals with measurements of Lp(a), 2527 aged 20 to 79 with a history of CVD were studied. The primary end point was major adverse cardiovascular event (MACE). We also studied 1115 individuals with CVD from the CCHS (Copenhagen City Heart Study; 1991-1994) and the CIHDS (Copenhagen Ischemic Heart Disease Study; 1991-1993). During a median follow-up of 5 years (range, 0-13), 493 individuals (20%) experienced a MACE in the CGPS. MACE incidence rates per 1000 person-years were 29 (95% CI, 25-34) for individuals with Lp(a)<10 mg/dL, 35 (30-41) for 10 to 49 mg/dL, 42 (34-51) for 50 to 99 mg/dL, and 54 (42-70) for ≥100 mg/dL. Compared with individuals with Lp(a)<10 mg/dL (18 nmol/L), the multifactorially adjusted MACE incidence rate ratios were 1.28 (95% CI, 1.03-1.58) for 10 to 49 mg/dL (18-104 nmol/L), 1.44 (1.12-1.85) for 50 to 99 mg/dL (105-213 nmol/L), and 2.14 (1.57-2.92) for ≥100 mg/dL (214 nmol/L). Independent confirmation was obtained in individuals from the CCHS and CIHDS. To achieve 20% and 40% MACE risk reduction in secondary prevention, we estimated that plasma Lp(a) should be lowered by 50 mg/dL (95% CI, 27-138; 105 nmol/L [55-297]) and 99 mg/dL (95% CI, 54-273; 212 nmol/L [114-592]) for 5 years. CONCLUSIONS: High concentrations of Lp(a) are associated with high risk of recurrent CVD in individuals from the general population. This study suggests that Lp(a)-lowering by 50 mg/dL (105 nmol/L) short-term (ie, 5 years) may reduce CVD by 20% in a secondary prevention setting.

Apolipoprotein(a) Kinetics in Statin-Treated Patients With Elevated Plasma Lipoprotein(a) Concentration.

BACKGROUND: Lipoprotein(a) [Lp(a)] is a low-density lipoprotein‒like particle containing apolipoprotein(a) [apo(a)]. Patients with elevated Lp(a), even when treated with statins, are at increased risk of cardiovascular disease. We investigated the kinetic basis for elevated Lp(a) in these patients. OBJECTIVES: Apo(a) production rate (PR) and fractional catabolic rate (FCR) were compared between statin-treated patients with and without elevated Lp(a). METHODS: The kinetics of apo(a) were investigated in 14 patients with elevated Lp(a) and 15 patients with normal Lp(a) levels matched for age, sex, and body mass index using stable isotope techniques and compartmental modeling. All 29 patients were on background statin treatment. Plasma apo(a) concentration was measured using liquid chromatography-mass spectrometry. RESULTS: The plasma concentration and PR of apo(a) were significantly higher in patients with elevated Lp(a) than in patients with normal Lp(a) concentration (all P < 0.01). The FCR of apo(a) was not significantly different between the groups. In univariate analysis, plasma concentration of apo(a) was significantly associated with apo(a) PR in both patient groups (r = 0.699 and r = 0.949, respectively; all P < 0.01). There was no significant association between plasma apo(a) concentration and FCR in either of the groups (r = 0.160 and r = -0.137, respectively). CONCLUSION: Elevated plasma Lp(a) concentration is a consequence of increased hepatic production of Lp(a) particles in these patients. Our findings provide a kinetic rationale for the use of therapies that target the synthesis of apo(a) and production of Lp(a) particles in patients with elevated Lp(a).

Comparative effect of tumour necrosis factor inhibitors versus other biological agents on cardiovascular risk-associated biomarkers in patients with rheumatoid arthritis.

Background: To comparatively investigate the differential effect of second-line tumour necrosis factor inhibitors (TNFis) versus other biological agents on cardiovascular disease (CVD) risk-associated biomarkers in patients with rheumatoid arthritis (RA). Methods: We evaluated the serum levels of lipoprotein-associated apoproteins ApoA1 and ApoB100 and lipoprotein(a) (Lp(a)) and the leptin/adiponectin ratio (LAR) as an insulin resistance proxy in patients with RA from the Rotation Or Change (ROC) trial treated with either a second-line TNFi or another biologic (tocilizumab (TCZ), rituximab or abatacept) at baseline and week 24. We compared the changes in biomarker levels in each group and according to the EULAR response. Results: Of the 300 patients enrolled in the ROC trial, 203 were included in the study, including 96 in the second-line TNFi group and 107 in the other biological group. The measured biomarkers did not deteriorate between baseline and week 24 regardless of the group. A greater improvement in the LAR was noted in the other biological group (median (IQR) -0.12 ng/µg (-0.58 to 0.31) vs 0.04 (-0.19 to 0.43), p=0.033), and a greater improvement in the Lp(a) level was observed following treatment with TCZ than with a TNFi (-0.05 g/L (-0.11 to -0.01) vs -0.01 g/L (-0.02 to 0.01), p<0.001). When considering the patients' responses to treatment, improved biomarkers were mainly observed in the EULAR responders in each treatment group. Conclusions: TNFis and non-TNFis were neutral on improved CVD risk-associated biomarkers in patients with RA insufficiently controlled by TNFis. TCZ could be associated with a better improvement concerning Lp(a) and LAR than TNFis. This improvement could be related to a good therapeutic response, thereby supporting the need of good control of RA. Trial registration number: ClinicalTrials.gov Identifier NCT01000441, registered on 22 October 2009.

The effects of coenzyme Q10 supplementation on lipid profiles among patients with coronary artery disease: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Chronic inflammation and increased oxidative stress significantly contribute in developing coronary artery disease (CAD). Hence, antioxidant supplementation might be an appropriate approach to decrease the incidence of CAD. This systematic review and meta-analysis was aimed to determine the effects of coenzyme Q10 (CoQ10) supplementation on lipid profile, as one of the major triggers for CAD, among patients diagnosed with coronary artery disease. METHODS: EMBASE, Scopus, PubMed, Cochrane Library, and Web of Science were searched for studies prior to May 20th, 2018. Cochrane Collaboration risk of bias tool was applied to assess the methodological quality of included trials. I-square and Q-tests were used to measure the existing heterogeneity across included studies. Considering heterogeneity among studies, fixed- or random-effect models were applied to pool standardized mean differences (SMD) as overall effect size. RESULTS: A total of eight trials (267 participants in the intervention group and 259 in placebo group) were included in the current meta-analysis. The findings showed that taking CoQ10 by patients with CAD significantly decreased total-cholesterol (SMD -1.07; 95% CI, - 1.94, - 0.21, P = 0.01) and increased HDL-cholesterol levels (SMD 1.30; 95% CI, 0.20, 2.41, P = 0.02). We found no significant effects of CoQ10 supplementation on LDL-cholesterol (SMD -0.37; 95% CI, - 0.87, 0.13, P = 0.14), lipoprotein (a) [Lp(a)] levels (SMD -1.12; 95% CI, - 2.84, 0.61, P = 0.20) and triglycerides levels (SMD 0.01; 95% CI, - 0.22, 0.24, P = 0.94). CONCLUSIONS: This meta-analysis demonstrated the promising effects of CoQ10 supplementation on lowering lipid levels among patients with CAD, though it did not affect triglycerides, LDL-cholesterol and Lp(a) levels.

Baseline and on-statin treatment lipoprotein(a) levels for prediction of cardiovascular events: individual patient-data meta-analysis of statin outcome trials.

BACKGROUND: Elevated lipoprotein(a) is a genetic risk factor for cardiovascular disease in general population studies. However, its contribution to risk for cardiovascular events in patients with established cardiovascular disease or on statin therapy is uncertain. METHODS: Patient-level data from seven randomised, placebo-controlled, statin outcomes trials were collated and harmonised to calculate hazard ratios (HRs) for cardiovascular events, defined as fatal or non-fatal coronary heart disease, stroke, or revascularisation procedures. HRs for cardiovascular events were estimated within each trial across predefined lipoprotein(a) groups (15 to <30 mg/dL, 30 to <50 mg/dL, and ≥50 mg/dL, vs <15 mg/dL), before pooling estimates using multivariate random-effects meta-analysis. FINDINGS: Analyses included data for 29 069 patients with repeat lipoprotein(a) measurements (mean age 62 years [SD 8]; 8064 [28%] women; 5751 events during 95 576 person-years at risk). Initiation of statin therapy reduced LDL cholesterol (mean change -39% [95% CI -43 to -35]) without a significant change in lipoprotein(a). Associations of baseline and on-statin treatment lipoprotein(a) with cardiovascular disease risk were approximately linear, with increased risk at lipoprotein(a) values of 30 mg/dL or greater for baseline lipoprotein(a) and 50 mg/dL or greater for on-statin lipoprotein(a). For baseline lipoprotein(a), HRs adjusted for age and sex (vs <15 mg/dL) were 1·04 (95% CI 0·91-1·18) for 15 mg/dL to less than 30 mg/dL, 1·11 (1·00-1·22) for 30 mg/dL to less than 50 mg/dL, and 1·31 (1·08-1·58) for 50 mg/dL or higher; respective HRs for on-statin lipoprotein(a) were 0·94 (0·81-1·10), 1·06 (0·94-1·21), and 1·43 (1·15-1·76). HRs were almost identical after further adjustment for previous cardiovascular disease, diabetes, smoking, systolic blood pressure, LDL cholesterol, and HDL cholesterol. The association of on-statin lipoprotein(a) with cardiovascular disease risk was stronger than for on-placebo lipoprotein(a) (interaction p=0·010) and was more pronounced at younger ages (interaction p=0·008) without effect-modification by any other patient-level or study-level characteristics. INTERPRETATION: In this individual-patient data meta-analysis of statin-treated patients, elevated baseline and on-statin lipoprotein(a) showed an independent approximately linear relation with cardiovascular disease risk. This study provides a rationale for testing the lipoprotein(a) lowering hypothesis in cardiovascular disease outcomes trials. FUNDING: Novartis Pharma AG.

Controlled study of the effect of proprotein convertase subtilisin-kexin type 9 inhibition with evolocumab on lipoprotein(a) particle kinetics.

Aims: Lipoprotein(a) [Lp(a)], a low-density lipoprotein (LDL) particle covalently bound to apolipoprotein(a) [apo(a)], is a potentially potent heritable risk factor for cardiovascular disease. We investigated the mechanism whereby evolocumab, a monoclonal antibody against proprotein convertase subtilisin-kexin type 9 (PCSK9), lowers Lp(a). Methods and results: We studied the kinetics of Lp(a) particles in 63 healthy men, with plasma apo(a) concentration >5 nmol/L, participating in an 8-week factorial trial of the effects of evolocumab (420 mg every 2 weeks) and atorvastatin (80 mg daily) on lipoprotein metabolism. Lipoprotein(a)-apo(a) kinetics were studied using intravenous D3-leucine administration, mass spectrometry, and compartmental modelling; Lp(a)-apoB kinetics were also determined in 16 subjects randomly selected from the treatment groups. Evolocumab, but not atorvastatin, significantly decreased the plasma pool size of Lp(a)-apo(a) (-36%, P < 0.001 for main effect). As monotherapy, evolocumab significantly decreased the production of Lp(a)-apo(a) (-36%, P < 0.001). In contrast, in combination with atorvastatin, evolocumab significantly increased the fractional catabolism of Lp(a)-apo(a) (+59%, P < 0.001), but had no effect on the production of Lp(a)-apo(a). There was a highly significant association between the changes in the fractional catabolism of Lp(a)-apo(a) and Lp(a)-apoB in the substudy of 16 subjects (r = 0.966, P < 0.001). Conclusions: Evolocumab monotherapy lowered the plasma Lp(a) pool size by decreasing the production of Lp(a) particles. In combination with atorvastatin, evolocumab lowered the plasma Lp(a) pool size by accelerating the catabolism of Lp(a) particles. This dual mechanism may relate to an effect of PCSK9 inhibition on Lp(a)-apo(a) production and to marked up-regulation of LDL receptor activity on Lp(a) holoparticle clearance. Clinical Trial Registration Information: NCT02189837.

Lipoprotein(a): the revenant.

In the mid-1990s, the days of lipoprotein(a) [Lp(a)] were numbered and many people would not have placed a bet on this lipid particle making it to the next century. However, genetic studies brought Lp(a) back to the front-stage after a Mendelian randomization approach used for the first time provided strong support for a causal role of high Lp(a) concentrations in cardiovascular disease and later also for aortic valve stenosis. This encouraged the use of therapeutic interventions to lower Lp(a) as well numerous drug developments, although these approaches mainly targeted LDL cholesterol, while the Lp(a)-lowering effect was only a 'side-effect'. Several drug developments did show a potent Lp(a)-lowering effect but did not make it to endpoint studies, mainly for safety reasons. Currently, three therapeutic approaches are either already in place or look highly promising: (i) lipid apheresis (specific or unspecific for Lp(a)) markedly decreases Lp(a) concentrations as well as cardiovascular endpoints; (ii) PCSK9 inhibitors which, besides lowering LDL cholesterol also decrease Lp(a) by roughly 30%; and (iii) antisense therapy targeting apolipoprotein(a) which has shown to specifically lower Lp(a) concentrations by up to 90% in phase 1 and 2 trials without influencing other lipids. Until the results of phase 3 outcome studies are available for antisense therapy, we will have to exercise patience, but with optimism since never before have we had the tools we have now to prove Koch's extrapolated postulate that lowering high Lp(a) concentrations might be protective against cardiovascular disease.

Treatment with the natural FXR agonist chenodeoxycholic acid reduces clearance of plasma LDL whilst decreasing circulating PCSK9, lipoprotein(a) and apolipoprotein C-III.

BACKGROUND: The natural farnesoid X receptor (FXR) agonist chenodeoxycholic acid (CDCA) suppresses hepatic cholesterol and bile acid synthesis and reduces biliary cholesterol secretion and triglyceride production. Animal studies have shown that bile acids downregulate hepatic LDL receptors (LDLRs); however, information on LDL metabolism in humans is limited. METHODS: Kinetics of autologous 125 I-LDL were determined in 12 male subjects at baseline and during treatment with CDCA (15 mg kg-1 day-1 ). In seven patients with gallstones treated with CDCA for 3 weeks before cholecystectomy, liver biopsies were collected and analysed for enzyme activities and for specific LDLR binding. Serum samples obtained before treatment and at surgery were analysed for markers of lipid metabolism, lipoproteins and the LDLR modulator proprotein convertase subtilisin/kexin type 9 (PCSK9). RESULTS: Chenodeoxycholic acid treatment increased plasma LDL cholesterol by ~10% as a result of reduced clearance of plasma LDL-apolipoprotein (apo)B; LDL production was somewhat reduced. The reduction in LDL clearance occurred within 1 day after initiation of treatment. In CDCA-treated patients with gallstones, hepatic microsomal cholesterol 7α-hydroxylase and HMG-CoA reductase activities were reduced by 83% and 54%, respectively, and specific LDLR binding was reduced by 20%. During treatment, serum levels of fibroblast growth factor 19 and total and LDL cholesterol increased, whereas levels of 7α-hydroxy-4-cholesten-3-one, lathosterol, PCSK9, apoA-I, apoC-III, lipoprotein(a), triglycerides and insulin were reduced. CONCLUSIONS: Chenodeoxycholic acid has a broad influence on lipid metabolism, including reducing plasma clearance of LDL. The reduction in circulating PCSK9 may dampen its effect on hepatic LDLRs and plasma LDL cholesterol. Further studies of the effects of other FXR agonists on cholesterol metabolism in humans seem warranted, considering the renewed interest for such therapy in liver disease and diabetes.

Effect of Alirocumab on Lipoprotein(a) Over ≥1.5 Years (from the Phase 3 ODYSSEY Program).

Elevated lipoprotein(a) [Lp(a)] is independently associated with increased cardiovascular risk. However, treatment options for elevated Lp(a) are limited. Alirocumab, a monoclonal antibody to proprotein convertase subtilisin/kexin type 9, reduced low-density lipoprotein cholesterol (LDL-C) by up to 62% from baseline in phase 3 studies, with adverse event rates similar between alirocumab and controls. We evaluated the effect of alirocumab on serum Lp(a) using pooled data from the phase 3 ODYSSEY program: 4,915 patients with hypercholesterolemia from 10 phase 3 studies were included. Eight studies evaluated alirocumab 75 mg every 2 weeks (Q2W), with possible increase to 150 mg Q2W at week 12 depending on LDL-C at week 8 (75/150 mg Q2W); the other 2 studies evaluated alirocumab 150-mg Q2W from the outset. Comparators were placebo or ezetimibe. Eight studies were conducted on a background of statins, and 2 studies were carried out with no statins. Alirocumab was associated with significant reductions in Lp(a), regardless of starting dose and use of concomitant statins. At week 24, reductions from baseline were 23% to 27% with alirocumab 75/150-mg Q2W and 29% with alirocumab 150-mg Q2W (all comparisons p <0.0001 vs controls). Reductions were sustained over 78 to 104 weeks. Lp(a) reductions with alirocumab were independent of race, gender, presence of familial hypercholesterolemia, baseline Lp(a), and LDL-C concentrations, or use of statins. In conclusion, in addition to marked reduction in LDL-C, alirocumab leads to a significant and sustained lowering of Lp(a).

Current therapies for lowering lipoprotein (a).

Lipoprotein (a) [Lp(a)] is a human plasma lipoprotein with unique structural and functional characteristics. Lp(a) is an assembly of two components: a central core with apoB and an additional glycoprotein, called apo(a). Ever since the strong association between elevated levels of Lp(a) and an increased risk for CVD was recognized, interest in the therapeutic modulation of Lp(a) levels has increased. Here, the past and present therapies aiming to lower Lp(a) levels will be reviewed, demonstrating that these agents have had varying degrees of success. The next challenge will be to prove that Lp(a) lowering also leads to cardiovascular benefit in patients with elevated Lp(a) levels. Therefore, highly specific and potent Lp(a)-lowering strategies are awaited urgently.

Reduction in lipoprotein(a) with PCSK9 monoclonal antibody evolocumab (AMG 145): a pooled analysis of more than 1,300 patients in 4 phase II trials.

OBJECTIVES: The purpose of this study was assess the effect of evolocumab (AMG 145) on lipoprotein (Lp)(a) from a pooled analysis of 4 phase II trials. BACKGROUND: Lp(a), a low-density lipoprotein (LDL) particle linked to the plasminogen-like glycoprotein apolipoprotein(a), shows a consistent and independent positive association with cardiovascular disease risk in epidemiological studies. Current therapeutic options to reduce Lp(a) are limited. METHODS: A pooled analysis of data from 1,359 patients in 4 phase II trials assessed the effects of evolocumab, a fully human monoclonal antibody to PCSK9, on Lp(a), the relationship between Lp(a) and lowering of low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B, and the influence of background statin therapy. Lp(a) was measured using a standardized isoform-independent method. RESULTS: Evolocumab treatment for 12 weeks resulted in significant (p < 0.001) mean (95% confidence interval) dose-related reductions in Lp(a) compared to control: 29.5% (23.3% to 35.7%) and 24.5% (20.4% to 28.7%) with 140 mg and 420 mg, dosed every 2 and 4 weeks, respectively, with no plateau of effect. Lp(a) reductions were significantly correlated with percentages of reductions in LDL-C (Spearman correlation coefficient, 0.5134; p < 0.001) and apolipoprotein B (Spearman correlation coefficient, 0.5203; p < 0. 001). Mean percentage reductions did not differ based on age or sex but the trend was greater in those patients taking statins. CONCLUSIONS: Inhibition of PCSK9 with evolocumab resulted in significant dose-related reductions in Lp(a). While the mean percentage of reduction was significantly greater in those patients with baseline Lp(a) of ≤125 nmol/l, the absolute reduction was substantially larger in those with levels >125 nmol/l.

New therapeutic principles in dyslipidaemia: focus on LDL and Lp(a) lowering drugs.

Dyslipidaemias play a key role in determining cardiovascular risk; the discovery of statins has contributed a very effective approach. However, many patients do not achieve, at the maximal tolerated dose, the recommended goals for low-density lipoprotein-cholesterol (LDL-C), non-high-density lipoprotein-cholesterol, and apolipoprotein B (apoB). Available agents combined with statins can provide additional LDL-C reduction, and agents in development will increase therapeutic options impacting also other atherogenic lipoprotein classes. In fact, genetic insights into mechanisms underlying regulation of LDL-C levels has expanded potential targets of drug therapy and led to the development of novel agents. Among them are modulators of apoB containing lipoproteins production and proprotein convertase subtilisin/kexin type-9 inhibitors. Alternative targets such as lipoprotein(a) also require attention; however, until we have a better understanding of these issues, further LDL-C lowering in high and very high-risk patients will represent the most sound clinical approach.

Lipoprotein(a) metabolism: potential sites for therapeutic targets.

Lipoprotein(a) [Lp(a)] resembles low-density lipoprotein (LDL), with an LDL lipid core and apolipoprotein B (apoB), but contains a unique apolipoprotein, apo(a). Elevated Lp(a) is an independent risk factor for coronary and peripheral vascular diseases. The size and concentration of plasma Lp(a) are related to the synthetic rate, not the catabolic rate, and are highly variable with small isoforms associated with high concentrations and pathogenic risk. Apo(a) is synthesized in the liver, although assembly of apo(a) and LDL may occur in the hepatocytes or plasma. While the uptake and clearance site of Lp(a) is poorly delineated, the kidney is the site of apo(a) fragment excretion. The structure of apo(a) has high homology to plasminogen, the zymogen for plasmin and the primary clot lysis enzyme. Apo(a) interferes with plasminogen binding to C-terminal lysines of cell surface and extracellular matrix proteins. Lp(a) and apo(a) inhibit fibrinolysis and accumulate in the vascular wall in atherosclerotic lesions. The pathogenic role of Lp(a) is not known. Small isoforms and high concentrations of Lp(a) are found in healthy octogenarians that suggest Lp(a) may also have a physiological role. Studies of Lp(a) function have been limited since it is not found in commonly studied small mammals. An important aspect of Lp(a) metabolism is the modification of circulating Lp(a), which has the potential to alter the functions of Lp(a). There are no therapeutic drugs that selectively target elevated Lp(a), but a number of possible agents are being considered. Recently, new modifiers of apo(a) synthesis have been identified. This review reports the regulation of Lp(a) metabolism and potential sites for therapeutic targets.

Consistency of extended-release niacin/laropiprant effects on Lp(a), ApoB, non-HDL-C, Apo A1, and ApoB/ApoA1 ratio across patient subgroups.

BACKGROUND: According to prior analyses, extended-release niacin/laropiprant (ERN/LRPT) consistently reduces low-density lipoprotein cholesterol (LDL-C) and triglycerides (TG) and increases high-density lipoprotein cholesterol (HDL-C) levels across a wide range of dyslipidemic patient subgroups. OBJECTIVES: This analysis examined ERN/LRPT's consistency across four phase III, randomized, double-blind trials in improving other lipid/lipoprotein parameters associated with cardiovascular risk, across several key dyslipidemic patient subgroups. METHODS: In three of the studies, the randomized population included patients with primary hypercholesterolemia or mixed hyperlipidemia; in the remaining study, the population included patients with type 2 diabetes mellitus. The lipid-altering consistency of ERN/LRPT's efficacy was evaluated versus the pre-defined comparator (placebo or active control) among key subgroups of sex, race (White, non-White), region (US, ex-US), baseline age (<65 years, ≥65 years), use of statin therapy (yes, no), coronary heart disease (yes, no), risk status (low, multiple, high), and type of hyperlipidemia (primary hypercholesterolemia, mixed dyslipidemia), as well as across baseline LDL-C, HDL-C, and TG levels. The consistency of the treatment effects on lipoprotein(a).[Lp(a)], apolipoprotein B (ApoB), non-HDL-C, ApoA1, and ApoB/ApoA1 ratio was evaluated by examining treatment difference estimates of the percentage change from baseline with 95% confidence intervals. RESULTS: Treatment with ERN/LRPT produced significantly greater improvements in Lp(a), ApoB, non-HDL-C, ApoA1, and ApoB/ApoA1 ratio compared with placebo/active comparator in each study. These effects were generally consistent across key subgroups within each study. CONCLUSION: ERN/LRPT produced lipid-altering efficacy on the parameters evaluated in four controlled studies; these effects were generally consistent across all examined subgroups. ERN/LRPT represents an effective and reliable therapeutic option for the treatment of dyslipidemia in a wide range of patient types. CLINICAL TRIAL REGISTRATION: Registered as Clinicaltrials.gov NCT00269204, NCT00269217, NCT00479388, and NCT00485758.

Effects of omega-3 fatty acids on serum lipids, lipoprotein (a), and hematologic factors in hemodialysis patients.

BACKGROUND: Lipid abnormalities, especially high serum lipoprotein (a) [Lp (a)] concentration, and anemia are two major causes of cardiovascular diseases (CVDs) in hemodialysis patients. Therefore, this study was designed to investigate the effects of marine omega-3 fatty acids on serum lipids, Lp (a), and hematologic factors in hemodialysis patients. METHODS: Thirty-four hemodialysis patients were randomly assigned to either omega-3 fatty acid supplement or placebo group. Patients in the omega-3 fatty acids group received 2080 mg marine omega-3 fatty acids, daily for 10 weeks, whereas the placebo group received a corresponding placebo. At baseline and the end of week 10, 7 mL blood was collected after a 12- to 14-h fast and serum triglyceride, total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), Lp (a), blood hemoglobin, hematocrit, red blood cells (RBCs), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) were measured. RESULTS: Serum triglyceride decreased significantly in the omega-3 fatty acids group at the end of week 10 compared with baseline (p < 0.05) and this reduction was significant in comparison with the placebo group (p < 0.01). No significant differences were observed between the two groups in mean changes of serum total cholesterol, LDL-C, HDL-C, Lp (a), blood hemoglobin, hematocrit, RBC, MCV, MCH, and MCHC. CONCLUSION: The results of our study indicate that marine omega-3 fatty acids can reduce serum triglyceride, as a risk factor for CVD, but it does not affect other serum lipids, Lp (a), and hematologic factors in hemodialysis patients.