Efficacy and safety of alirocumab in high cardiovascular risk patients with inadequately controlled hypercholesterolaemia on maximally tolerated doses of statins: the ODYSSEY COMBO II randomized controlled trial

Alirocumab in patients with heterozygous familial hypercholesterolaemia undergoing lipoprotein apheresis: the ODYSSEY ESCAPE trial

AIM

To evaluate the effect of alirocumab on frequency of standard apheresis treatments [weekly or every 2 weeks (Q2W)] in heterozygous familial hypercholesterolaemia (HeFH).

METHODS AND RESULTS

ODYSSEY ESCAPE (NCT02326220) was a double-blind study in 62 HeFH patients undergoing regular weekly or Q2W lipoprotein apheresis. Patients were randomly assigned (2:1, respectively) to receive alirocumab 150 mg (n = 41) or placebo (n = 21) Q2W subcutaneously for 18 weeks. From day 1 to week 6, apheresis rate was fixed according to the patient's established schedule; from weeks 7 to 18, apheresis rate was adjusted based on the patient's low-density lipoprotein cholesterol (LDL-C) response in a blinded fashion. Apheresis was not performed when the LDL-C value was ≥30% lower than the baseline (pre-apheresis) value. The primary efficacy endpoint was the rate of apheresis treatments over 12 weeks (weeks 7-18), standardized to number of planned treatments. In the alirocumab group the least square (LS) mean ± SE (95% confidence interval [CI]) per cent change in pre-apheresis LDL-C from baseline at week 6 was -53.7 ± 2.3 (-58.2 to - 49.2) compared with 1.6 ± 3.1 (-4.7 to 7.9) in the placebo group. The primary efficacy endpoint showed statistically significant benefit in favour of alirocumab (Hodges-Lehmann median estimate of treatment difference: 0.75; 95% CI 0.67-0.83; P < 0.0001). Therefore, alirocumab-treated patients had a 0.75 (75%) additional reduction in the standardized rate of apheresis treatments vs. placebo-treated patients. During this period, 63.4% of patients on alirocumab avoided all and 92.7% avoided at least half of the apheresis treatments. Adverse event rates were similar (75.6% of patients on alirocumab vs. 76.2% on placebo).

CONCLUSIONS

Lipoprotein apheresis was discontinued in 63.4% of patients on alirocumab who were previously undergoing regular apheresis, and the rate was at least halved in 92.7% of patients. Alirocumab was generally safe and well tolerated.

Management of Hypercholesterolemia, Appropriateness of Therapeutic Approaches and New Drugs in Patients with High Cardiovascular Risk

Control of lipid levels is one of the most effective strategies for cardiovascular (CV) event prevention. In fact, many clinical trials have clearly demonstrated that low-density lipoprotein cholesterol (LDL-C) lowering, primarily with statins, reduces major CV events and mortality. The evidence from these trials has been useful in designing the cholesterol treatment guidelines, which are mainly aimed at preventing and managing cardiovascular disease (CVD). However, available data indicate that a large proportion of patients fail to achieve lipid goals, and this is particularly frequent in patients at high or very high CV risk. Furthermore, owing to side effects, a significant percentage of patients cannot tolerate statin treatment. Hence, researchers have focused their attention on novel LDL-C-lowering agents that act via mechanisms distinct from that of statins. Among the new compounds under investigation, the monoclonal antibodies to proprotein convertase subtilisin/kexin type 9 (PCSK9) seem particularly promising, having recently been shown to be well tolerated and highly effective at lowering LDL-C, with a possible effect on the occurrence of CV events. Currently, alirocumab is approved by the US Food and Drug Administration (FDA) as an adjunct to diet and maximally tolerated statin therapy for use in adults with heterozygous familial hypercholesterolemia (FH) or those with atherosclerotic CV disease who require additional LDL-C lowering; it has also been recently approved by the European Medicines Agency (EMA) for use in patients with heterozygous FH, non–familial hypercholesterolemia or mixed dyslipidemia in whom statins are ineffective or not tolerated. Evolocumab is approved by the FDA as an adjunct to diet and maximally tolerated statins for adults with hetero- and homozygous FH and those with atherosclerotic CV disease who require additional lowering of LDL-C, and by the EMA in adults with primary hypercholesterolemia or mixed dyslipidemia, as an adjunct to diet, in combination with a statin or a statin with other lipid lowering therapies in patients unable to reach LDL-C goals with the maximum tolerated dose of a statin; alone or in combination with other lipid lowering therapies in patients who are statin-intolerant, or those for whom a statin is contraindicated. Evolocumab is also indicated in adults and adolescents aged 12 years and over with homozygous familial hypercholesterolemia in combination with other lipid-lowering therapies.

Biology of proprotein convertase subtilisin kexin 9: beyond low-density lipoprotein cholesterol lowering

Proprotein convertase subtilisin kexin 9 (PCSK9) is a key regulator of low-density lipoprotein receptor levels and LDL-cholesterol levels. Loss-of-function mutations in PCSK9 gene are associated with hypocholesterolaemia and protection against cardiovascular disease, identifying PCSK9 inhibition as a valid therapeutic approach to manage hypercholesterolaemia and related diseases. Although PCSK9 is expressed mainly in the liver, it is present also in other tissues and organs with specific functions, raising the question of whether a pharmacological inhibition of PCSK9 to treat hypercholesterolaemia and associated cardiovascular diseases might be helpful or deleterious in non-hepatic tissues. For example, PCSK9 is expressed in the vascular wall, in the kidneys, and in the brain, where it was proposed to play a role in development, neurocognitive process, and neuronal apoptosis. A link between PCSK9 and immunity was also proposed as both sepsis and viral infections are differentially affected in the presence or absence of PCSK9. Despite the increasing number of observations, the debate on the exact roles of PCSK9 in extrahepatic tissues is still ongoing, and as very effective drugs that inhibit PCSK9 have become available to the clinician, a better understanding of the biological roles of PCSK9 is warranted.

Therapeutic efficacy of PCSK9 monoclonal antibodies in statin-nonresponsive patients with hypercholesterolemia and dyslipidemia: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Heterozygous familial hypercholesterolemia and dyslipidemia are the predominant causes for cardiovascular disease (CVD). Clinical guidelines for lowering CVD risk have advocated that low density lipoprotein-cholesterol (LDL-C) must be reduced. The primary choice of therapy for controlling lipidemia has been statins, which are not completely effective. Proprotein convertase subtilisin/kexin type-9 (PCSK9), which interferes with LDL clearance from circulation, inversely relates to the LDL-C levels. The loss of statin efficacy is likely due to increased circulating PCSK9 and antibody therapy against PCSK9 has been found to be efficacious in lowering LDL-C. In this study, we evaluated the efficacy of PCSK9-mAbs for lowering LDL-C, in statin non-responsive hypercholesterolemia patients.

STUDY DESIGN AND METHODS

PubMed, EMBASE, Scholar, Web of Science and Scopus databases were searched to identify randomized controlled trials of PCSK9 antibody-statin combination vs statin, published till 2015. Two reviewers independently screened the articles, and a collective decision was reached about the included studies in the metaanalysis. Parameters analyzed: change from baseline in LDL-C, high-density lipoprotein cholesterol (HDL-C) and total cholesterol (TC); ApoB and ApoA1 levels.

RESULTS

A total of 12 studies with 4909 patients were selected. Overall, add-on therapy with PCSK9-mAb to the ongoing statin therapy was found to achieve greater reduction in LDL-C, ApoB, TC, compared to statin therapy. There were no major treatment emergent adverse effects due to PCSK9-mAb therapy.

CONCLUSIONS

In adult patients with heterozygous familial hypercholesterolemia and dyslipidemia, PCSK9-mAb therapy in combination with statins was able to achieve the goal of lowering LDL-C.

No effect of PCSK9 inhibitor alirocumab on the incidence of diabetes in a pooled analysis from 10 ODYSSEY Phase 3 studies

Aims

Statins have modest adverse effects on glycaemic control. Alirocumab, a proprotein convertase subtilisin/kexin type 9 inhibitor, lowers low-density lipoprotein cholesterol. This study assessed the effects of alirocumab on new-onset diabetes and pre-diabetes incidence in individuals without diabetes at baseline.

Methods and results

Pooled analysis of 10 ODYSSEY Phase 3 trials (n = 4974) of 24–104 weeks duration. Six trials (n = 4211) were ≥52 weeks in length. Most patients received background maximally tolerated statin. Alirocumab effect on the rate of diabetes-related treatment-emergent adverse events (TEAEs), and/or fasting plasma glucose (FPG) and glycated haemoglobin A_1C (HbA_1C) was measured at baseline and every 12–24 weeks. Transition to diabetes analysis combined TEAE and FPG/HbA_1C laboratory data. At baseline, 30.7% of individuals had diabetes and were excluded from the current analysis. The remaining 3448 individuals without diabetes had pre-diabetes (39.6%) or were normoglycaemic (29.7%). The hazard ratio (HR; 95% confidence interval) for diabetes-related TEAEs in alirocumab was 0.64 (0.36–1.14) vs. placebo and 0.55 (0.22–1.41) vs. ezetimibe. The HR associated for transition from pre-diabetes to new-onset diabetes for alirocumab was 0.90 (0.63–1.29) vs. placebo and 1.10 (0.57–2.12) vs. ezetimibe. Mean change in FPG/HbA_1C over time showed no difference between treatment groups in patients without diabetes.

Conclusions

There was no evidence of an effect of alirocumab on transition to new-onset diabetes in 3448 individuals without diabetes at baseline with a follow-up period of 6–18 months, compared to either placebo or ezetimibe. Longer follow-up with larger number of individuals is needed to conclusively rule out an effect.

Efficacy and Safety of Alirocumab in Japanese Patients With Heterozygous Familial Hypercholesterolemia or at High Cardiovascular Risk With Hypercholesterolemia Not Adequately Controlled With Statins - ODYSSEY JAPAN Randomized Controlled Trial

BACKGROUND

The ODYSSEY Japan study was designed to demonstrate the reduction in low-density lipoprotein cholesterol (LDL-C) by alirocumab as add-on to existing lipid-lowering therapy in Japanese patients with heterozygous familial hypercholesterolemia (heFH) or non-FH at high cardiovascular risk who require additional pharmacological management to achieve their LDL-C treatment goal (<2.6 or <3.1 mmol/L, depending on risk category).

METHODS AND RESULTS

This randomized, double-blind, parallel-group, 52-week study was conducted in Japan. Patients (n=216) with heFH, non-FH at high cardiovascular risk with coronary disease, or classified as category III were enrolled. The prespecified safety analysis was done after the last patient completed 52 weeks. Patients were randomized (2:1, alirocumab:placebo) with stratification for heFH to s.c. alirocumab (75 mg every 2 weeks [Q2 W] with increase to 150 mg if week 8 LDL-C ≥2.6/3.1 mmol/L) or placebo for 52 weeks plus stable statin therapy. At week 24, mean±SE change in LDL-C from baseline was -62.5±1.3% in the alirocumab group and 1.6±1.8% in the placebo group (difference, -64.1±2.2%; P<0.0001); the reduction was sustained to week 52 (alirocumab, -62.5±1.4%; placebo, -3.6±1.9%). No patterns were evident between treatment groups for adverse events at 52 weeks.

CONCLUSIONS

In high-risk Japanese patients with hypercholesterolemia on stable statin therapy, alirocumab markedly reduced LDL-C vs. placebo and was well tolerated over 52 weeks. (Circ J 2016; 80: 1980-1987).

Focus on PCSK9 Inhibitors: From Genetics to Clinical Practice

Elevation of low-density lipoprotein cholesterol (LDL-C) is an important cause of atherosclerotic cardiovascular disease (ASCVD). Over the years, clinical outcome studies with LDL-C lowering agents have revealed that reducing LCL-C levels is effective in reducing rates of major ASCVD events. Although secondary factors play a role in clinical expression, severe lipid disorders often have a strong genetic component. Genetic revelations have provided novel targets for improving LDL-C management in high-risk individuals. Most recently, researchers have explored how the inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9) alters LDL metabolism and lowers LDL-C levels to achieve lipid goals and potentially reduce ASCVD risk in patients with severe lipid disorders, including familial hypercholesterolemia (FH). This CMHC Spotlight article summarizes the clinical evidence demonstrating the safety, tolerability, and efficacy of PCSK9 inhibitors in lowering LDL-C levels. Reductions in LDL-C levels by PCSK9 inhibitors alone in patients who are statin intolerant or combined with maximally tolerated statins in patients with severe lipid disorders demonstrate the potential for reduced morbidity and mortality associated with ASCVD.

Efficacy and Safety of Alirocumab in Japanese Subjects (Phase 1 and 2 Studies)

We assessed the safety and tolerability of ascending single doses of alirocumab in healthy Japanese subjects and evaluated the effect of alirocumab at 3 doses (50, 75, 150 mg) on low-density lipoprotein cholesterol (LDL-C) reduction in patients with primary hypercholesterolemia on atorvastatin. A randomized, single ascending-dose study of alirocumab (100, 150, 250, or 300 mg) or placebo (3:1 ratio), administered subcutaneously, was conducted in 32 healthy Japanese men. The phase 2, randomized, double-blind, placebo-controlled, parallel-group study was performed in patients with primary hypercholesterolemia (defined as calculated LDL-C ≥100 mg/dl [2.6 mmol/l]) who were on a stable dose of atorvastatin (5 to 20 mg). Patients were randomized to alirocumab (50, 75, or 150 mg) or placebo (in single 1.0-ml injection volumes) administered every 2 weeks (Q2W) for 12 weeks; the primary outcome was the mean percent change in calculated LDL-C from baseline to week 12. Single subcutaneous administration of alirocumab in healthy subjects was well tolerated over 15 weeks and resulted in highest mean percent reductions in LDL-C from baseline of approximately 40% to 60%. In the multiple-dose study, least-square mean (SE) changes in calculated LDL-C concentrations from baseline to week 12 were -54.8% (3.1%) for alirocumab 50 mg, -62.3% (3.1%) for alirocumab 75 mg, and -71.7% (3.1%) for alirocumab 150 mg, with a least-square mean (SE) difference versus placebo of -52.2% (4.3%), -59.6% (4.3%), and -69.1% (4.3%), respectively (all p <0.0001). In conclusion, alirocumab was well tolerated and significantly reduced LDL-C concentrations in Japanese patients with primary hypercholesterolemia on atorvastatin.

Alirocumab: First Global Approval

Alirocumab (Praluent®) is a fully human monoclonal antibody developed by Regeneron Pharmaceuticals and Sanofi that has been approved in the US as an adjunct to diet and maximally tolerated statin therapy for the treatment of adults with heterozygous familial hypercholesterolaemia (HeFH) or clinical atherosclerotic cardiovascular disease, who require additional lowering of LDL-C. It specifically binds proprotein convertase subtilisin/kexin type 9 (PCSK9)-a down regulator of liver low-density lipoprotein (LDL)-receptors-thereby increasing the ability of the liver to bind LDL-cholesterol (LDL-C) and reducing levels of LDL-C in blood. It has been shown to reduce LDL-C levels in patients with hypercholesterolaemia, including HeFH, both as monotherapy and in conjunction with statin therapy. This article summarizes the milestones in the development of alirocumab leading to this first approval.

Effect of ETC-1002 on Serum Low-Density Lipoprotein Cholesterol in Hypercholesterolemic Patients Receiving Statin Therapy

ETC-1002 is an oral, once-daily medication that inhibits adenosine triphosphate citrate lyase, an enzyme upstream of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, to reduce cholesterol biosynthesis. ETC-1002 monotherapy has demonstrated significant reduction in low-density lipoprotein cholesterol (LDL-C) compared with placebo in phase 2 studies. The objective of this study was to compare the lipid-lowering efficacy of ETC-1002 versus placebo when added to ongoing statin therapy in patients with hypercholesterolemia. This phase 2b, multicenter, double-blind trial (NCT02072161) randomized 134 hypercholesterolemic patients (LDL-C, 115 to 220 mg/dl) on stable background statin therapy to 12 weeks of add-on treatment with ETC-1002 120 mg, ETC-1002 180 mg, or placebo. The primary efficacy end point was the percent change in calculated LDL-C from baseline to week 12. For LDL-C, the least-squares mean percent change ± standard error from baseline to week 12 was significantly greater with ETC-1002 120 mg (-17 ± 4%, p = 0.0055) and ETC-1002 180 mg (-24 ± 4%, p <0.0001) than placebo (-4 ± 4%). ETC-1002 also dose dependently reduced apolipoprotein B by 15% to 17%, non-high-density lipoprotein cholesterol by 14% to 17%, total cholesterol by 13% to 15%, and LDL particle number by 17% to 21%. All these reductions in ETC-1002-treated cohorts were significantly greater than those with placebo. Rates of adverse events (AEs), muscle-related AEs, and discontinuations for AEs with ETC-1002 were similar to placebo. In conclusion, ETC-1002 120 mg or 180 mg added to stable statin therapy significantly reduced LDL-C compared to placebo and has a similar tolerability profile.

Relationship Between Low-Density Lipoprotein Cholesterol, Free Proprotein Convertase Subtilisin/Kexin Type 9, and Alirocumab Levels After Different Lipid-Lowering Strategies

Background

Alirocumab undergoes target‐mediated clearance via binding of proprotein convertase subtilisin/kexin type 9 (PCSK9). Statins increase PCSK9 levels; the effects of nonstatin lipid‐lowering therapies are unclear. Every‐4‐weeks dosing of alirocumab may be appropriate for some patients in absence of background statin but is not yet approved.

Methods and Results

Low‐density lipoprotein cholesterol (LDL‐C), PCSK9, and alirocumab levels were assessed in subjects (LDL‐C >130 mg/dL, n=24/group) after a 4‐week run‐in taking oral ezetimibe, fenofibrate, or ezetimibe placebo, when alirocumab 150 mg every 4 weeks (days 1, 29, and 57) was added. Maximal mean LDL‐C reductions from day −1 baseline (prealirocumab) occurred on day 71 in all groups: alirocumab plus placebo, 47.4%; alirocumab plus ezetimibe, 56.6%; and alirocumab plus fenofibrate, 54.3%. LDL‐C reductions were sustained through day 85 with alirocumab plus placebo (47.0%); the duration of effect was slightly diminished at day 85 versus day 71 with ezetimibe (49.6%) or fenofibrate combinations (43.2%). Free PCSK9 concentrations were lowest at day 71 in all groups, then increased over time; by day 85, free PCSK9 concentrations were higher, and alirocumab levels lower, with alirocumab plus fenofibrate, and to a lesser extent alirocumab plus ezetimibe, versus alirocumab plus placebo.

Conclusions

Alirocumab 150 mg every 4 weeks produced maximal LDL‐C reductions of 47% in combination with placebo and 54% to 57% in combination with ezetimibe or fenofibrate. The oral lipid‐lowering therapies appear to increase PCSK9 levels, leading to increased alirocumab clearance. Although the duration of effect was modestly diminished with alirocumab plus ezetimibe/fenofibrate versus placebo, the effect was less than observed in trials with background statins, and it would not preclude the use of alirocumab every 4 weeks in patients taking these nonstatin lipid‐lowering therapies concomitantly.

Clinical Trial Registration

URL: http://www.Clinicaltrials.gov. Unique identifier: NCT01723735.

A Systematic Review of PCSK9 Inhibitors Alirocumab and Evolocumab

BACKGROUND

The proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors are a new class of cholesterol-lowering medications that provide significant reductions in lipids but at a large cost relative to statins. With 2 such drugs now on the market, alirocumab and evolocumab, comparing the evidence base for these drugs is necessary for informed decision making.

OBJECTIVE

To compare the benefits and harms of the PCSK9 inhibitors alirocumab and evolocumab.

METHODS

The databases Ovid MEDLINE, Cochrane Library, SCOPUS, and ClinicalTrials.gov were used to search for randomized controlled trials of alirocumab or evolocumab with any relevant comparator reporting health outcomes, lipid outcomes, or harms through September 2015, and information was requested from manufacturers. Results were reviewed according to standard review methods.

RESULTS

The database searches revealed 17 fair- and good-quality trials; however, none had primary health outcomes or directly compared PCSK9 inhibitors. Alirocumab (75 mg to 150 mg subcutaneously every 2 weeks) resulted in significantly greater reductions in low-density lipoprotein cholesterol (LDL-C; -8% to -67%) at 12-24 weeks in patients with (a) heterozygous familial hypercholesterolemia and (b) patients at high or varied cardiovascular (CV) risk who were not at LDL-C goals with statin therapy. The highest strength evidence was for patients with high CV risk not at LDL-C goals. Alirocumab also resulted in high-density lipoprotein cholesterol (HDL-C) increases of 6%-12%. Low- and moderate-strength evidence for adjudicated CV events at 52-78 weeks for a priori analyses indicated no benefit. Low- and moderate-strength evidence also found no differences in harms except possibly slightly more injection-site reactions. Evolocumab (120 mg subcutaneously every 2 weeks to 420 mg every 4 weeks) resulted in significantly greater reductions in LDL-C (-32% to -71%) at 12-52 weeks in patients with heterozygous or homozygous familial hypercholesterolemia, patients intolerant of statins, and patients with varied CV risk not at LDL-C goal with statin therapy. The highest strength evidence was for heterozygous familial hypercholesterolemia and patients not at LDL-C goals. Moderate-strength evidence showed HDL-C increases in the range of 4.5%-6.8%. Harms were not different between groups, except possibly slightly greater overall adverse event reporting. Evidence on adjudicated CV outcomes was insufficient to draw conclusions because of sparseness of events, study limitations, and inability to assess consistency of findings.

CONCLUSIONS

Alirocumab and evolocumab have evidence of large improvements in lipid levels. The strength of the evidence is greater for alirocumab than evolocumab in patients with high CV risk who were not at LDL-C target goals, while evidence for evolocumab is stronger in patients with heterogeneous familial hypercholesterolemia and patients with varied CV risk who were not at LDL-C target goals. Evidence on adjudicated CV outcomes for a priori analyses is unable to show benefit for alirocumab and is insufficient to draw conclusions for evolocumab. Important questions remain about the comparative effects on long-term health outcomes.

DISCLOSURES

This project was funded by The Drug Effectiveness Review Project. Project participants reviewed the manuscript but had no role in conducting the work or writing the manuscript. Any comments received from the participants during the course of the review were taken at the discretion of the authors independently. All authors had access to the data and a role in writing the manuscript. McDonagh, Peterson, and Holzhammer declare no conflict of interest or financial interest in any therapy discussed in this article. Fazio declares receiving compensation from Sanofi for a presentation on his science to a group of their advisors and has served as a consultant to MSD, BASF, NHP, Sanofi, Ionis Pharmaceuticals, and Kowa. Study concept and design were primarily contributed by McDonagh, along with Peterson and Holzhammer, with assistance from Fazio. Holzhammer took the lead in data collection, with assistance from McDonagh and Peterson. Data interpretation was performed by McDonagh, Peterson, and Fazio. The manuscript was written by McDonagh, Peterson, and Fazio, with assistance from Holzhammer, and revised by all the authors.

PCSK9 inhibition in the management of hyperlipidemia: focus on evolocumab

Proprotein convertase subtilisin/kexin type 9 (PCSK9) increases low-density lipoprotein cholesterol (LDL-C) concentrations through interference with normal physiologic hepatic LDL receptor (LDLR) recycling. Inhibiting PCSK9 results in improved LDLR recycling, increased LDLR availability on hepatocyte cell surfaces, and reduced blood LDL-C levels, making PCSK9 inhibition a novel therapeutic strategy for managing hypercholesterolemia. Monoclonal antibodies directed against PCSK9 have been developed for this purpose. A large number of clinical trials have demonstrated that monoclonal antibodies against PCSK9 yield substantial reductions in LDL-C when administered as monotherapy or in combination with statins to patients with nonfamilial and familial forms of hypercholesterolemia. Data from long-term trials demonstrate that the LDL-C-lowering effect of PCSK9 inhibitors is durable. These agents are generally well tolerated, and few patients discontinue treatment due to adverse events. Moreover, PCSK9 inhibitors do not appear to elicit the hepatic and muscle-related side effects associated with statin use. The ultimate value of PCSK9 inhibitors will be measured by their effect on clinical outcomes. Early evidence of a reduction in cardiovascular events after 1 year of treatment was shown in a prospective exploratory analysis of two ongoing long-term open-label extension evolocumab trials. Similarly, cardiovascular events were reduced in another exploratory analysis after >1 year of therapy with alirocumab. For the primary care physician, PCSK9 inhibitors represent a welcome additional option for lowering LDL-C in patients with familial forms of hypercholesterolemia and those with clinical atherosclerotic cardiovascular disease who are on maximally tolerated statin therapy.

Targeting PCSK9 as a promising new mechanism for lowering low-density lipoprotein cholesterol

Statins and other lipid-lowering drugs have dominated the market for many years for achievement of recommended levels of low-density lipoprotein cholesterol (LDL-C). However, a substantial number of high-risk patients are unable to achieve the LDL-C goal. Proprotein convertase subtilisin/kexin 9 (PCSK9) has recently emerged as a new, promising key therapeutic target for hypercholesterolemia. PCSK9 is a protease involved in chaperoning the low-density lipoprotein receptor to the process of degradation. PCSK9 inhibitors and statins effectively lower LDL-C. The PCSK9 inhibitors decrease the degradation of the LDL receptors, whereas statins mainly interfere with the synthetic machinery of cholesterol by inhibiting the key rate limiting enzyme, the HMG CoA reductase. PCSK9 inhibitors are currently being developed as monoclonal antibodies for their primary use in lowering LDL-C. They may be especially useful for patients with homozygous familial hypercholesterolemia, who at present receive minimal benefit from traditional statin therapy. The monoclonal antibody PCSK9 inhibitors, recently granted FDA approval, show the most promising safety and efficacy profile compared to other, newer LDL-C lowering therapies. This review will primarily focus on the safety and efficacy of monoclonal antibody PCSK9 inhibitors in comparison to statins. The review will also address new, alternative PCSK9 targeting drug classes such as small molecules, gene silencing agents, apolipoprotein B antisense oligonucleotides, and microsomal triglyceride transfer protein inhibitors.

Alirocumab, a Therapeutic Human Antibody to PCSK9, Does Not Affect CD81 Levels or Hepatitis C Virus Entry and Replication into Hepatocytes

BACKGROUND

Proprotein convertase subtilisin/kexin type 9 (PSCK9) is secreted mainly from the liver and binds to the low-density lipoprotein receptor (LDLR), reducing LDLR availability and thus resulting in an increase in LDL-cholesterol. While the LDLR has been implicated in the cell entry process of the hepatitis C virus (HCV), overexpression of an artificial non-secreted, cell membrane-bound form of PCSK9 has also been shown to reduce surface expression of CD81, a major component of the HCV entry complex, leading to concerns that pharmacological inhibition of PCSK9 may increase susceptibility to HCV infection by increasing either CD81 or LDLR availability. Here, we evaluated effects of PCSK9 and PCSK9 blockade on CD81 levels and HCV entry with a physiologically relevant model using native secreted PCSK9 and a monoclonal antibody to PCSK9, alirocumab.

METHODS AND RESULTS

Flow cytometry and Western blotting of human hepatocyte Huh-7 cells showed that, although LDLR levels were reduced when cells were exposed to increasing PCSK9 concentrations, there was no correlation between total or surface CD81 levels and the presence and amount of soluble PCSK9. Moreover, inhibiting PCSK9 with the monoclonal antibody alirocumab did not affect expression levels of CD81. In an in vitro model of HCV entry, addition of soluble PCSK9 or treatment with alirocumab had no effect on the ability of either lentiviral particles bearing the HCV glycoproteins or JFH-1 based cell culture virus to enter hepatocytes. Consistent with these in vitro findings, no differences were observed in hepatic CD81 levels using in vivo mouse models, including Pcsk9-/- mice compared with wild-type controls and hyperlipidemic mice homozygous for human Pcsk9 and heterozygous for Ldlr deletion, treated with either alirocumab or isotype control antibody.

CONCLUSION

These results suggest that inhibition of PCSK9 with alirocumab has no effect on CD81 and does not result in increased susceptibility to HCV entry.

Statin combination therapy and cardiovascular risk reduction

In numerous clinical trials, lowering LDL-C with statin therapy has been demonstrated to reduce the risk of cardiovascular disease (CVD) in primary and secondary prevention settings. Guidelines recommend statins for first-line therapy in cholesterol-lowering management of patients with CVD risk. Despite increased statin monotherapy use over the last decade, a number of patients with high CVD risk do not achieve optimal LDL-C lowering. Guidelines recommend consideration of statin combination therapy with nonstatin agents for these patients. However, combination therapy approaches have been hampered by neutral findings. Recently, ezetimibe added to simvastatin therapy reduced cardiovascular events in acute coronary syndrome patients, more than simvastatin alone. This article provides an overview of various agents in combination with statin therapy on cardiovascular outcomes. Other lipid-lowering agents in development, including PCSK9 and CETP inhibitors in development, are also described.

PCSK9 inhibition as an emerging lipid lowering therapy: Unanswered questions

Although statins have been used for the treatment of hypercholesterolemia for more than two decades, cardiovascular disease (CVD), which is related at least in part to high levels of low-density lipoprotein cholesterol (LDL-C), is the number one cause of death in Europe and the USA. Several studies have shown that the reduction in cardiovascular (CV) events is proportional to the absolute LDL-C lowering achieved with statins. In the quest for further reduction in LDL-C and CV events, new drugs that mainly support statin action have emerged. Since 2003, with the discovery of proprotein convertase subtilisin/kexin type 9 (PCSK9), which is a key factor in the LDL clearance pathway, new modalities, mainly in the form of monoclonal antibodies that block this protein (PCSK9 inhibitors), have reached phase III of clinical development with very promising efficacy and safety data. With a mean further reduction of LDL-C levels of ∼60% beyond that achieved with statins, the PCSK9 inhibitors set the bar even lower in terms of LDL-C levels. This review manuscript addresses important questions about the efficacy, safety and clinical use of PCSK9 inhibitors to evaluate the role of these agents in reducing CV risk.

Effect of monoclonal antibodies to PCSK9 on high-sensitivity C-reactive protein levels: a meta-analysis of 16 randomized controlled treatment arms

AIMS

Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors are an emerging class of low-density lipoprotein cholesterol (LDL-C)-lowering agents. In spite of their known effects on lipids, the impact of these drugs on systemic inflammation is less known. We aimed to investigate the effect of PCSK9 inhibitors on high-sensitivity C-reactive protein (hs-CRP) levels through a meta-analysis of randomized controlled trials (RCTs).

METHODS

A systematic literature search of Medline, SCOPUS and Google Scholar was conducted up to December 2015 to identify RCTs assessing changes in hs-CRP concentrations during treatment with PCSK9 inhibitors. Quantitative data synthesis was performed using a random-effects model, with weighed mean difference (WMD) and 95% confidence interval (CI) as summary statistics.

RESULTS

Sixteen treatment arms, with a total of 2546 participants, were included. Random-effects meta-analysis did not show any significant effect of PCSK9 inhibitors on hs-CRP levels (WMD: 0.002 mg l(-1) , CI: -0.017, 0.021; P = 0.807; I(2) = 37.26%). This effect size was robust, not sensitive to any single study, and not affected by the type of PCSK9 inhibitor (evolocumab: WMD: 0.002 mg l(-1) , CI: -0.02, 0.02; P = 0.855; alirocumab WMD: 0.15 mg l(-1) , CI: -0.11, 0.40; P = 0.259; I(2) = 0%), or dosing frequency (biweekly: WMD: 0.13 mg l(-1) , CI: -0.20, 0.46; P = 0.433; I(2) = 55.19%; monthly: WMD: 0.003 mg l(-1) , CI: -0.01, 0.01; P = 0.59; I(2) = 0%). Random-effects meta-regression did not suggest any association of changes in hs-CRP levels with changes in plasma LDL-C concentrations (P = 0.697) or cumulative dosage of the drug (P = 0.980).

CONCLUSIONS

This meta-analysis of RCTs did not suggest an effect of PCSK9 inhibitors on hs-CRP concentrations.

Alirocumab: A Review in Hypercholesterolemia

Alirocumab (Praluent(®)) is a monoclonal antibody against proprotein convertase subtilisin/kexin type 9 (PCSK9) that is administered via subcutaneous injection every 2 weeks. Across ten phase III studies from the ODYSSEY clinical trial program in patients with heterozygous familial hypercholesterolemia (heFH) or nonfamilial hypercholesterolemia (nonFH), including some with mixed dyslipidemia, subcutaneous alirocumab 75 or 150 mg every 2 weeks was significantly more effective with regard to reducing low-density lipoprotein-cholesterol (LDL-C) over 24 weeks than comparator agents (i.e. matching placebo, once-daily oral ezetimibe, or modified oral statin therapy), including when administered as monotherapy or in combination with statin therapy, and when administered with non-statin lipid-lowering therapy (LLT) in patients with statin intolerance. Alirocumab provided sustained LDL-C-lowering efficacy over 52-78 weeks' treatment in longer-term trials, and was associated with significantly favorable effects on several other lipid parameters, including non-high-density lipoprotein-cholesterol (non-HDL-C) and lipoprotein (a) [Lp(a)]. Alirocumab was generally well tolerated in phase III trials, with no apparent increase in muscle-related adverse events compared with placebo. Thus, alirocumab is a valuable emerging option for use in patients with hypercholesterolemia, particularly patients with statin intolerance or inadequately-controlled LDL-C despite statin therapy; however, more data are needed to establish its potential cardiovascular benefits.

Alirocumab for hyperlipidemia: ODYSSEY Phase III clinical trial results and US FDA approval indications

A new class of lipid-lowering drugs, inhibitors of PCSK9 has been generating impressive clinical trial data over the last several years, and alirocumab (Praluent) has become the first to be approved by the US FDA. Alirocumab has been shown to lower low density lipoprotein cholesterol by 45–62% with a safety profile generally comparable to placebo. Alirocumab is a monoclonal antibody to PCSK9 administered subcutaneously and has been evaluated in 16 Phase III clinical trials, the majority of which have been enrolled or completed. This article will be a review of the available Phase III safety and efficacy data of the ODYSSEY studies including a brief description of each of the 16 studies.

PCSK9 inhibitors and their role in high-risk patients in reducing LDL cholesterol levels: alirocumab

In this review, we examine alirocumab (Praluent(®)), a monoclonal antibody to PCSK9 and its role in reducing LDL-C levels. By comparing the results of various studies and trials we discuss the efficacy and safety of alirocumab. We aim to guide clinicians of the role of alirocumab in clinical practice. Overall, PCSK9 inhibitors are promising new agents in further reducing LDL-C levels in addition to diet and maximally tolerated statin therapy. Long-term outcome studies are currently ongoing and will further delineate the role of PCSK9 inhibitors.

Promising new therapies for the treatment of hypercholesterolemia

INTRODUCTION

Statins are currently the most commonly used agents for treatment of hypercholesterolemia in patients with atherosclerotic cardiovascular disease. However, some patients on statins do not achieve their treatment goals or are intolerant to statins. Therefore, new therapies for treatment of hypercholesterolemia are under investigation.

AREAS COVERED

This article reviews the new emerging medications for the treatment of hypercholesterolemia and discusses their efficacy and safety profile based on literature searches that included human studies published on PubMed and reported clinical trials.

EXPERT OPINION

Inhibition of the PCSK9 protein by monoclonal antibodies results in a dramatic 40%-60% lowering of serum low-density lipoprotein cholesterol (LDL-C). This is in addition to LDL-C lowering achieved by statins. Multiple clinical studies have demonstrated the high selectivity of these antibodies for the PCSK9 pathway and their long-term safety and efficacy. Alirocumab and evolocumab have been approved by the FDA for the treatment of patients with heterozygous familial hypercholesterolemia and patients with clinical atherosclerotic cardiovascular disease) who do not achieve their LDL-C target on maximal tolerated statin treatment and dietary modification. In addition, evolocumab has been approved by the FDA for homozygous familial hypercholesterolemia. However, the long-term efficacy and safety of PCSK9 inhibitors are unknown.

Two new lipid-regulating drugs

▼Evolocumab (Repatha-Amgen Ltd) and ▼alirocumab (Praluent-Sanofi) are the first in a novel class of lipid-regulating drugs, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, to be licensed in the UK. Both drugs have marketing authorisation for the treatment of primary hypercholesterolaemia (heterozygous familial and non-familial) or mixed dyslipidaemia and are administered by subcutaneous injection. Here we consider the evidence for evolocumab and alirocumab in the management of primary hypercholesterolaemia and dyslipidaemias.

Effect of alirocumab on specific lipoprotein non-high-density lipoprotein cholesterol and subfractions as measured by the vertical auto profile method: analysis of 3 randomized trials versus placebo

Background

The effect of alirocumab on potentially atherogenic lipoprotein subfractions was assessed in a post hoc analysis using the vertical auto profile (VAP) method.

Methods

Patients from three Phase II studies with low-density lipoprotein cholesterol (LDL-C) ≥2.59 mmol/L (100 mg/dL) at baseline on stable statin therapy were randomised to receive subcutaneous alirocumab 50–150 mg every 2 weeks (Q2W) or 150–300 mg every 4 weeks (according to study) or placebo for 8–12 weeks. Samples from patients treated with alirocumab 150 mg Q2W (n = 74; dose common to all three trials) or placebo (n = 71) were analysed by VAP. Percent change in lipoprotein subfractions with alirocumab vs. placebo was analysed at Weeks 6, 8 or 12 using analysis of covariance.

Results

Alirocumab significantly reduced LDL-C and the cholesterol content of subfractions LDL₁, LDL₂ and LDL₃₊₄. Significant reductions were also observed in triglycerides, apolipoproteins CII and CIII and the cholesterol content of very low-density, intermediate-density, and remnant lipoproteins.

Conclusion

Alirocumab achieved reductions across a spectrum of atherogenic lipoproteins in patients receiving background statin therapy.

Trial registration

Clinicaltrials.gov identifiers: NCT01288443, NCT01288469, NCT01266876

Electronic supplementary material

The online version of this article (doi:10.1186/s12944-016-0197-4) contains supplementary material, which is available to authorized users.

The impact of proprotein convertase subtilisin-kexin type 9 serine protease inhibitors on lipid levels and outcomes in patients with primary hypercholesterolaemia: a network meta-analysis

AIMS

We performed a network meta-analysis of randomized controlled trials (RCTs) in patients with primary hypercholesterolaemia to compare the impact of proprotein convertase subtilisin-kexin type 9 serine protease (PCSK9) inhibitors with placebo and ezetimibe on lipid levels and outcomes.

METHODS AND RESULTS

MEDLINE/PubMed, Cochrane CENTRAL, and ClinicalTrials.gov were searched for RCTs assessing PCSK9 inhibitors vs. other therapies in patients with primary hypercholesterolaemia. Network meta-analysis with both a frequentist approach and a Bayesian framework was performed to directly and indirectly compare PCSK9 inhibition on lipid levels with ezetimibe and placebo. Odds ratios with 95% confidence intervals (OR [95% CIs]) were generated with random-effects models to compare outcomes. Our meta-analysis included 17 RCTs with 13 083 patients that were randomized to PCSK9 inhibitors (n = 8250), placebo (n = 3957), ezetimibe (n = 846), or PCSK9 inhibitors and ezetimibe (n = 30). The mean age was 59 ± 10, 52% were male, 34% had coronary artery disease, 51% had hypertension, 19% had diabetes mellitus, baseline LDL of 122 ± 36 mg/dL, total cholesterol of 199 ± 39 mg/dL, and HDL of 51 ± 14 mg/dL. inhibitors significantly reduced LDL cholesterol by 57% relative to placebo (P < 0.001) and 36.1% relative to ezetimibe (P < 0.001). Proprotein convertase subtilisin-kexin type 9 serine protease inhibitors reduced the incidence of all-cause mortality [OR 0.43 (95% CI 0.22-0.82), P = 0.01] but was associated with an increased incidence of neurocognitive adverse events [OR 2.34 (95% CI 1.11-4.93), I(2) = 4%, P = 0.02] when compared with placebo.

CONCLUSION

Proprotein convertase subtilisin-kexin type 9 serine protease inhibition significantly improved lipid profiles and reduced the incidence of all-cause mortality compared with placebo but had a higher rate of neurocognitive adverse events. Thus, PCSK9 inhibitor therapy may serve as an alternative for patients with statin intolerance and for those who do not respond to other lipid reduction therapy.

Prognostic value of PCSK9 levels in patients with acute coronary syndromes

AIMS

Proprotein convertase subtilisin kexin 9 (PCSK9) is an emerging target for the treatment of hypercholesterolaemia, but the clinical utility of PCSK9 levels to guide treatment is unknown. We aimed to prospectively assess the prognostic value of plasma PCSK9 levels in patients with acute coronary syndromes (ACS).

METHODS AND RESULTS

Plasma PCSK9 levels were measured in 2030 ACS patients undergoing coronary angiography in a Swiss prospective cohort. At 1 year, the association between PCSK9 tertiles and all-cause death was assessed adjusting for the Global Registry of Acute Coronary Events (GRACE) variables, as well as the achievement of LDL cholesterol targets of <1.8 mmol/L. Patients with higher PCSK9 levels at angiography were more likely to have clinical familial hypercholesterolaemia (rate ratio, RR 1.21, 95% confidence interval, CI 1.09-1.53), be treated with lipid-lowering therapy (RR 1.46, 95% CI 1.30-1.63), present with longer time interval of chest pain (RR 1.29, 95% CI 1.09-1.53) and higher C-reactive protein levels (RR 1.22, 95% CI 1.16-1.30). PCSK9 increased 12-24 h after ACS (374 ± 149 vs. 323 ± 134 ng/mL, P < 0.001). At 1 year follow-up, HRs for upper vs. lower PCSK9-level tertiles were 1.13 (95% CI 0.69-1.85) for all-cause death and remained similar after adjustment for the GRACE score. Patients with higher PCSK9 levels were less likely to reach the recommended LDL cholesterol targets (RR 0.81, 95% CI 0.66-0.99).

CONCLUSION

In ACS patients, high initial PCSK9 plasma levels were associated with inflammation in the acute phase and hypercholesterolaemia, but did not predict mortality at 1 year.

Proprotein convertase subtilisin/kexin type 9 inhibition: a new therapeutic mechanism for reducing cardiovascular disease risk

Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays an important role in the regulation of cholesterol homeostasis. By binding to hepatic low-density lipoprotein (LDL) receptors and promoting their lysosomal degradation, PCSK9 reduces LDL uptake, leading to an increase in LDL cholesterol concentrations. Gain-of-function mutations in PCSK9 associated with high LDL cholesterol and premature cardiovascular disease have been causally implicated in the pathophysiology of autosomal-dominant familial hypercholesterolemia. In contrast, the more commonly expressed loss-of-function mutations in PCSK9 are associated with reduced LDL cholesterol and cardiovascular disease risk. The development of therapeutic approaches that inhibit PCSK9 function has therefore attracted considerable attention from clinicians and the pharmaceutical industry for the management of hypercholesterolemia and its associated cardiovascular disease risk. This review summarizes the effects of PCSK9 on hepatic and intestinal lipid metabolism and the more recently explored functions of PCSK9 in extrahepatic tissues. Therapeutic approaches that prevent interaction of PCSK9 with hepatic LDL receptors (monoclonal antibodies, mimetic peptides), inhibit PCSK9 synthesis in the endoplasmic reticulum (antisense oligonucleotides, siRNAs), and interfere with PCSK9 function (small molecules) are also described. Finally, clinical trials testing the safety and efficacy of monoclonal antibodies to PCSK9 are reviewed. These have shown dose-dependent decreases in LDL cholesterol (44%-65%), apolipoprotein B (48%-59%), and lipoprotein(a) (27%-50%) without major adverse effects in various high-risk patient categories, including those with statin intolerance. Initial reports from 2 of these trials have indicated the expected reduction in cardiovascular events. Hence, inhibition of PCSK9 holds considerable promise as a therapeutic option for decreasing cardiovascular disease risk.

Development and Content Validity Testing of a Patient-Reported Treatment Acceptance Measure for Use in Patients Receiving Treatment via Subcutaneous Injection

BACKGROUND

New therapies in development for lowering low-density lipoprotein cholesterol, such as alirocumab, require administration by subcutaneous injections. There is a need to assess the acceptance of such treatments and their mode of administration.

OBJECTIVES

To develop a novel patient-reported outcome measure, the Injection-Treatment Acceptance Questionnaire (I-TAQ), and assess its content validity using qualitative methods.

METHODS

Concepts generated from a literature and instrument review informed the initial drafting of 17 items in the I-TAQ, with item wording adapted from three existing instruments. Three rounds of qualitative interviews were conducted with 29 US-English speaking patients at high cardiovascular risk. Concept elicitation questioning was used to explore patients' treatment experiences followed by cognitive debriefing of the I-TAQ using "think-aloud" methods. Verbatim transcripts were analyzed using thematic analysis.

RESULTS

Qualitative analysis of concept elicitation data identified the following relevant concepts: perceived efficacy, side effects, self-efficacy, convenience, and overall acceptance. Seven (24%) patients discussed an initial fear of needles, but described this as subsiding with no impact on adherence. Five items were added after round one interviews, three of which were retained after round two testing in which two further items were added, forming the conceptually comprehensive 22-item I-TAQ. Patients demonstrated good understanding of item wording, instructions, response scales, and recall period.

CONCLUSIONS

Successive rounds of in-depth interviews resulted in a treatment acceptance measure with strong content validity. Pending demonstration of its psychometric properties, the I-TAQ may prove to be a valuable measure of patients' perspectives toward being treated with low-density lipoprotein cholesterol-lowering therapies requiring subcutaneous injections.

PCSK9 inhibitors and cardiovascular disease: heralding a new therapeutic era

PURPOSE OF REVIEW

The first monoclonal antibodies targeting proprotein convertase subtilisin/kexin type 9 (PCSK9) have been approved for clinical use. This timely review highlights recent developments.

RECENT FINDINGS

Low-density lipoprotein cholesterol (LDL-C) is the primary driver of atherosclerosis and the key target for intervention. Yet despite best treatment including statins, attaining sufficient LDL-C lowering can be problematic for high cardiovascular risk patients. The development of PCSK9 inhibitors, driven by novel genetic and mechanistic insights, offers an answer. Removal of circulating PCSK9 increases LDL receptor availability, and thus markedly decreases plasma LDL-C levels (by ∼50-60%), and is additive to the lipid lowering effects of statins and ezetimibe. PCSK9 inhibition also reduces (by 25-30%) plasma levels of lipoprotein(a), a causal factor in atherosclerotic vascular disease, suggestive of partial catabolism of lipoprotein(a) by LDL receptors. The ODYSSEY and PROFICIO (Programme to Reduce LDL-C and Cardiovascular Outcomes Following Inhibition of PCSK9 In Different Populations) clinical trial programmes involving a wide range of high-risk patients, including statin intolerant patients, have confirmed the consistency of the LDL response, even with concomitant high-intensity statin or nonstatin therapy. Extensive evidence to date attests to a favourable safety and tolerability profile for these innovative agents.

SUMMARY

The new pharmacotherapeutic era of PCSK9 inhibition is upon us, promising major reduction in cardiovascular events across a wide spectrum of high-risk patients.

The PCSK9 Inhibitors: A Novel Therapeutic Target Enters Clinical Practice

There is a critical need for alternative, potent agents that can reduce low-density lipoprotein cholesterol (LDL-C) levels in patients with heterozygous familial hyperlipidemia and statin intolerance and those not reaching lipid-lowering treatment goals who are at high risk for cardiovascular (CV) events. The first proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor was approved in July 2015 by the US Food and Drug Administration as an adjunct to diet and maximally tolerated statin therapy for treatment of adults with heterozygous familial hyperlipidemia or clinical atherosclerotic CV disease, who require additional lowering of LDL-C levels. In clinical trials, PCSK9 inhibitors have been shown to reduce LDL-C levels by as much as 60% to 70% when administered as monotherapy or as an add-on treatment to statins and other lipid-lowering therapies. In studies of PCSK9 genetic mutations, loss of function in the PCSK9 allele was associated with a relative decrease of 88% in the risk for atherosclerotic CV events during 15 years of patient follow-up. The use of PCSK9 inhibitors may eventually support the LDL-C hypothesis that the lower the LDL-C level, the lower the CV risk. Although some recent clinical practice guidelines have deemphasized the importance of numeric LDL-C targets, many clinicians are reluctant to discard them, and this position is supported by recent clinical evidence. We eagerly await the results of the ODYSSEY, FOURIER, and SPIRE clinical outcome trials, which we anticipate will provide further validation that "lower is better" with respect to reducing LDL-C levels and improving clinical outcomes.

Clinical implications of the IMPROVE-IT trial in the light of current and future lipid-lowering treatment options

INTRODUCTION

A residual risk of morbidity and mortality from cardiovascular (CV) disease remains despite statin therapy. This situation has generated an interest in finding novel approaches of combining statins with other lipid-lowering agents, or finding new lipid and non-lipid targets, such as triglycerides, high-density lipoprotein cholesterol (HDL-C), non-HDL-C, proprotein convertase subtilisin/kexin type 9 (PCSK9) gene, cholesterol ester transfer protein (CETP), lipoprotein (a), fibrinogen or C-reactive protein.

AREAS COVERED

The recent results from the IMProved Reduction of Outcomes: Vytorin Efficacy International Trial (IMPROVE-IT) demonstrated an incremental clinical benefit when ezetimibe, a non-statin agent, was added to simvastatin therapy.

EXPERT OPINION

The results from IMPROVE-IT revalidated the concept that low-density lipoprotein cholesterol (LDL-C) levels are a clinically relevant treatment goal. This trial also suggested that further decrease of LDL-C levels (53 vs. 70 mg/dl; 1.4 vs. 1.8 mmol/l) was more beneficial in lowering CV events. This "even lower is even better" evidence for LDL-C levels may influence future guidelines and the use of new drugs. Furthermore, these findings make ezetimibe a more realistic option to treat patients with statin intolerance or those who cannot achieve LDL-C targets with statin monotherapy.

Urine-sample-derived human induced pluripotent stem cells as a model to study PCSK9-mediated autosomal dominant hypercholesterolemia

Proprotein convertase subtilisin kexin type 9 (PCSK9) is a critical modulator of cholesterol homeostasis. Whereas PCSK9 gain-of-function (GOF) mutations are associated with autosomal dominant hypercholesterolemia (ADH) and premature atherosclerosis, PCSK9 loss-of-function (LOF) mutations have a cardio-protective effect and in some cases can lead to familial hypobetalipoproteinemia (FHBL). However, limitations of the currently available cellular models preclude deciphering the consequences of PCSK9 mutation further. We aimed to validate urine-sample-derived human induced pluripotent stem cells (UhiPSCs) as an appropriate tool to model PCSK9-mediated ADH and FHBL. To achieve our goal, urine-sample-derived somatic cells were reprogrammed into hiPSCs by using episomal vectors. UhiPSC were efficiently differentiated into hepatocyte-like cells (HLCs). Compared to control cells, cells originally derived from an individual with ADH (HLC-S127R) secreted less PCSK9 in the media (−38.5%; P=0.038) and had a 71% decrease (P<0.001) of low-density lipoprotein (LDL) uptake, whereas cells originally derived from an individual with FHBL (HLC-R104C/V114A) displayed a strong decrease in PCSK9 secretion (−89.7%; P<0.001) and had a 106% increase (P=0.0104) of LDL uptake. Pravastatin treatment significantly enhanced LDL receptor (LDLR) and PCSK9 mRNA gene expression, as well as PCSK9 secretion and LDL uptake in both control and S127R HLCs. Pravastatin treatment of multiple clones led to an average increase of LDL uptake of 2.19±0.77-fold in HLC-S127R compared to 1.38±0.49 fold in control HLCs (P<0.01), in line with the good response to statin treatment of individuals carrying the S127R mutation (mean LDL cholesterol reduction=60.4%, n=5). In conclusion, urine samples provide an attractive and convenient source of somatic cells for reprogramming and hepatocyte differentiation, but also a powerful tool to further decipher PCSK9 mutations and function.

Summary: The authors used urine-sample-derived patient-specific human induced pluripotent stem cells to generate hepatocytes carrying gain- or loss-of-function mutations of PCSK9, and mimicking the pathophysiology in vitro.

Effect of PCSK9 Inhibition by Alirocumab on Lipoprotein Particle Concentrations Determined by Nuclear Magnetic Resonance Spectroscopy

BACKGROUND

In patients with discordance between low-density lipoprotein (LDL) cholesterol and LDL particle (LDL-P) concentrations, cardiovascular risk more closely correlates with LDL-P.

METHODS AND RESULTS

We investigated the effect of alirocumab, a fully human monoclonal antibody to proprotein convertase subtilisin/kexin type 9, on lipoprotein particle concentration and size in hypercholesterolemic patients, using nuclear magnetic resonance spectroscopy. Plasma samples were collected from patients receiving alirocumab 150 mg every 2 weeks (n=26) or placebo (n=31) during a phase II, double-blind, placebo-controlled trial in patients (LDL cholesterol ≥100 mg/dL) on a stable atorvastatin dose. In this post hoc analysis, percentage change in concentrations of LDL-P, very-low-density lipoprotein particles, and high-density lipoprotein particles from baseline to week 12 was determined by nuclear magnetic resonance. Alirocumab significantly reduced mean concentrations of total LDL-P (-63.3% versus -1.0% with placebo) and large (-71.3% versus -21.8%) and small (-54.0% versus +17.8%) LDL-P subfractions and total very-low-density lipoprotein particle concentrations (-36.4% versus +33.4%; all P<0.01). Total high-density lipoprotein particles increased with alirocumab (+11.2% versus +1.4% with placebo; P<0.01). There were greater increases in large (44.6%) versus medium (17.7%) or small high-density lipoprotein particles (2.8%) with alirocumab. LDL-P size remained relatively unchanged in both groups; however, very-low-density and high-density lipoprotein particle sizes increased to a significantly greater extent with alirocumab.

CONCLUSIONS

Alirocumab significantly reduced LDL-C and LDL-P concentrations in hypercholesterolemic patients receiving stable atorvastatin therapy. These findings may be of particular relevance to patients with discordant LDL-C and LDL-P concentrations.

CLINICAL TRIAL REGISTRATION

URL: https://clinicaltrials.gov. Unique identifier: NCT01288443.

Efficacy and safety of adding alirocumab to rosuvastatin versus adding ezetimibe or doubling the rosuvastatin dose in high cardiovascular-risk patients: The ODYSSEY OPTIONS II randomized trial

OBJECTIVE

To compare lipid-lowering efficacy of adding alirocumab to rosuvastatin versus other treatment strategies (NCT01730053).

METHODS

Patients receiving baseline rosuvastatin regimens (10 or 20 mg) were randomized to: add-on alirocumab 75 mg every-2-weeks (Q2W) (1-mL subcutaneous injection via pre-filled pen); add-on ezetimibe 10 mg/day; or double-dose rosuvastatin. Patients had cardiovascular disease (CVD) and low-density lipoprotein cholesterol (LDL-C) ≥70 mg/dL (1.8 mmol/L) or CVD risk factors and LDL-C ≥100 mg/dL (2.6 mmol/L). In the alirocumab group, dose was blindly increased at Week 12 to 150 mg Q2W (also 1-mL volume) in patients not achieving their LDL-C target. Primary endpoint was percent change in calculated LDL-C from baseline to 24 weeks (intent-to-treat).

RESULTS

305 patients were randomized. In the baseline rosuvastatin 10 mg group, significantly greater LDL-C reductions were observed with add-on alirocumab (-50.6%) versus ezetimibe (-14.4%; p < 0.0001) and double-dose rosuvastatin (-16.3%; p < 0.0001). In the baseline rosuvastatin 20 mg group, LDL-C reduction with add-on alirocumab was -36.3% compared with -11.0% with ezetimibe and -15.9% with double-dose rosuvastatin (p = 0.0136 and 0.0453, respectively; pre-specified threshold for significance p < 0.0125). Overall, ∼80% alirocumab patients were maintained on 75 mg Q2W. Of alirocumab-treated patients, 84.9% and 66.7% in the baseline rosuvastatin 10 and 20 mg groups, respectively, achieved risk-based LDL-C targets. Treatment-emergent adverse events occurred in 56.3% of alirocumab patients versus 53.5% ezetimibe and 67.3% double-dose rosuvastatin (pooled data).

CONCLUSIONS

The addition of alirocumab to rosuvastatin provided incremental LDL-C lowering versus adding ezetimibe or doubling the rosuvastatin dose.

How Do PCSK9 Inhibitors Stack Up to Statins for Low-Density Lipoprotein Cholesterol Control?

Despite advances in the approach toward treating hypercholesterolemia and widespread access to statin medications, not all people are able to reach target low-density lipoprotein cholesterol (LDL-C) levels to reduce their cardiovascular risk. Some of the reasons include the inability to tolerate statin therapy, LDL-C levels that remain high even in the presence of statin therapy, and a familial disorder that is characterized by extremely high levels of LDL-C. A new therapeutic class, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, represents a novel and promising approach to reducing LDL-C levels using a mechanism at the LDL receptor level. The recent approval of the first 2 PCSK9 inhibitors and the anticipated approval of the third agent in this class within approximately 1 year may provide clinicians powerful new weapons to lower LDL-C levels in patients who are not satisfactorily managed with statins. However, the results of long-term studies of the ability of these new medications to influence cardiovascular outcomes will not be known for several years.

Efficacy and safety of alirocumab vs ezetimibe in statin-intolerant patients, with a statin rechallenge arm: The ODYSSEY ALTERNATIVE randomized trial

BACKGROUND

Statin intolerance limits many patients from achieving optimal low-density lipoprotein cholesterol (LDL-C) concentrations. Current options for such patients include using a lower but tolerated dose of a statin and adding or switching to ezetimibe or other non-statin therapies.

METHODS

ODYSSEY ALTERNATIVE (NCT01709513) compared alirocumab with ezetimibe in patients at moderate to high cardiovascular risk with statin intolerance (unable to tolerate ≥2 statins, including one at the lowest approved starting dose) due to muscle symptoms. A placebo run-in and statin rechallenge arm were included in an attempt to confirm intolerance. Patients (n = 361) received single-blind subcutaneous (SC) and oral placebo for 4 weeks during placebo run-in. Patients reporting muscle-related symptoms during the run-in were to be withdrawn. Continuing patients were randomized (2:2:1) to double-blind alirocumab 75 mg SC every 2 weeks (Q2W; plus oral placebo), ezetimibe 10 mg/d (plus SC placebo Q2W), or atorvastatin 20 mg/d (rechallenge; plus SC placebo Q2W) for 24 weeks. Alirocumab dose was increased to 150 mg Q2W at week 12 depending on week 8 LDL-C values. Primary end point was percent change in LDL-C from baseline to week 24 (intent-to-treat) for alirocumab vs ezetimibe.

RESULTS

Baseline mean (standard deviation) LDL-C was 191.3 (69.3) mg/dL (5.0 [1.8] mmol/L). Alirocumab reduced mean (standard error) LDL-C by 45.0% (2.2%) vs 14.6% (2.2%) with ezetimibe (mean difference 30.4% [3.1%], P < .0001). Skeletal muscle-related events were less frequent with alirocumab vs atorvastatin (hazard ratio 0.61, 95% confidence interval 0.38-0.99, P = .042).

CONCLUSIONS

Alirocumab produced greater LDL-C reductions than ezetimibe in statin-intolerant patients, with fewer skeletal-muscle adverse events vs atorvastatin.

Altered metabolism of LDL in the arterial wall precedes atherosclerosis regression

RATIONALE

Plasma cholesterol lowering is beneficial in patients with atherosclerosis. However, it is unknown how it affects entry and degradation of low-density lipoprotein (LDL) particles in the lesioned arterial wall.

OBJECTIVE

We studied the effect of lipid-lowering therapy on LDL permeability and degradation of LDL particles in atherosclerotic aortas of mice by measuring the accumulation of iodinated LDL particles in the arterial wall.

METHODS AND RESULTS

Cholesterol-fed, LDL receptor-deficient mice were treated with either an anti-Apob antisense oligonucleotide or a mismatch control antisense oligonucleotide once a week for 1 or 4 weeks before injection with preparations of iodinated LDL particles. The anti-Apob antisense oligonucleotide reduced plasma cholesterol by ≈90%. The aortic LDL permeability and degradation rates of newly entered LDL particles were reduced by ≈50% and ≈85% already after 1 week of treatment despite an unchanged pool size of aortic iodinated LDL particles. In contrast, the size, foam cell content, and aortic pool size of iodinated LDL particles of aortic atherosclerotic plaques were not reduced until after 4 weeks of treatment with the anti-Apob antisense oligonucleotide.

CONCLUSIONS

Improved endothelial barrier function toward the entry of plasma LDL particles and diminished aortic degradation of the newly entered LDL particles precede plaque regression.

ODYSSEY FH I and FH II: 78 week results with alirocumab treatment in 735 patients with heterozygous familial hypercholesterolaemia

Aims

To assess long-term (78 weeks) alirocumab treatment in patients with heterozygous familial hypercholesterolaemia (HeFH) and inadequate LDL-C control on maximally tolerated lipid-lowering therapy (LLT).

Methods and results

In two randomized, double-blind studies (ODYSSEY FH I, n = 486; FH II, n = 249), patients were randomized 2 : 1 to alirocumab 75 mg or placebo every 2 weeks (Q2W). Alirocumab dose was increased at Week 12 to 150 mg Q2W if Week 8 LDL-C was ≥1.8 mmol/L (70 mg/dL). Primary endpoint (both studies) was percentage change in calculated LDL-C from baseline to Week 24. Mean LDL-C levels decreased from 3.7 mmol/L (144.7 mg/dL) at baseline to 1.8 mmol/L (71.3 mg/dL; −57.9% vs. placebo) at Week 24 in patients randomized to alirocumab in FH I and from 3.5 mmol/L (134.6 mg/dL) to 1.8 mmol/L (67.7 mg/dL; −51.4% vs. placebo) in FH II (P < 0.0001). These reductions were maintained through Week 78. LDL-C <1.8 mmol/L (regardless of cardiovascular risk) was achieved at Week 24 by 59.8 and 68.2% of alirocumab-treated patients in FH I and FH II, respectively. Adverse events resulted in discontinuation in 3.4% of alirocumab-treated patients in FH I (vs. 6.1% placebo) and 3.6% (vs. 1.2%) in FH II. Rate of injection site reactions in alirocumab-treated patients was 12.4% in FH I and 11.4% in FH II (vs. 11.0 and 7.4% with placebo).

Conclusion

In patients with HeFH and inadequate LDL-C control at baseline despite maximally tolerated statin ± other LLT, alirocumab treatment resulted in significant LDL-C lowering and greater achievement of LDL-C target levels and was well tolerated.

Clinical trial registration

Cinicaltrials.gov (identifiers: NCT01623115; NCT01709500).

Patient and Physician Perspectives on Mode of Administration of the PCSK9 Monoclonal Antibody Alirocumab, an Injectable Medication to Lower LDL-C Levels

PURPOSE

Clinical trials of the PCSK9 inhibitor alirocumab, an every 2 week injectable monoclonal antibody, have shown significant reductions in LDL-cholesterol. However, many patients requiring lipid-lowering therapy are not experienced with self-injected medication. This study assessed patient and physician perceptions of 2 alirocumab delivery devices.

METHODS

400 participants (200 physicians, 200 patients) were included from 6 countries. Physicians (99 primary care physicians [PCPs]; 101 specialists) had mean practice experience of 17.8 years and an average of 797 hypercholesterolemic patients. Participating patients had LDL-C levels above their goal and at least one of the following: familial hypercholesterolemia, statin intolerance, high cardiovascular risk, and/or diabetes. Mean patient age was 58.5 years, 51% were female, and 25.5% had injectable medication experience. Following device instruction and demonstration, participants tested either a pre-filled pen or pre-filled syringe, using both 75 and 150 mg doses of single-blinded placebo into a prosthetic pad. Data were collected by self-administered questionnaire.

FINDINGS

Participant acceptance of both devices was positive, with 83-100% agreeing with ease-of-use statements. After testing, physicians estimated that 66% (pen) and 58% (syringe) of their patients would be willing to self-inject using the device (relative increases from pre-testing of 22% and 16%, respectively; both P<0.05). Specialist estimates were higher than PCP estimates: for the pen, 60% versus 47% (pre-testing), respectively, and 72% versus 61% (post-testing); for the syringe, 57% versus 43% (pre-testing), 63% versus 54% (post-testing; all P<0.05, specialist vs PCP). After testing, 72% (pen) and 63% (syringe) of patient-participants were very willing to self-inject (relative increases from pre-testing of 26% [P<0.05] and 11%, respectively); 96% (pen) and 93% (syringe) were either very willing or somewhat willing to self-inject. The proportion of patients aged <60 years who were very willing to self-inject with either device was numerically (but not statistically) higher compared with those ≥60 years. Initially, patients with injectable medication experience were generally more willing to use the pen than injection-naive patients; after testing there was no difference between groups. No significant differences were observed in responses to the 2 different doses.

IMPLICATIONS

Responses from physicians and patients to pre-filled pen and syringe devices were positive. Devices were considered easy to operate, with most patients willing to use and accept self-injection. Patient willingness to self-inject increased after demonstration and testing. Results suggest that, in clinical practice, alirocumab administration by either pre-filled pen or syringe would not deter most physicians from prescribing or most patients from self-administering.