Cingulate circuits are associated with escalation of heroin use and naloxone-induced increases in heroin self-administration

Opioid use disorder (OUD) is defined as a compulsion to seek and take opioids, loss of control over intake and the development of a negative emotional state when access to opioids is denied. Using functional magnetic resonance imaging (fMRI) data in a rat model of OUD, we demonstrate that the escalation of heroin self-administration (SA) and the increased heroin SA following an injection of an opioid receptor antagonist (naloxone) are associated with changes in distinct brain circuits, centered on the cingulate cortex (Cg). Here, SA escalation score was negatively associated with changes in resting state functional connectivity (rsFC) between the Cg and the dorsal striatum. Conversely, increased heroin SA following naloxone injection, was associated with increased connectivity between the Cg and the extended amygdala and hypothalamus. Naloxone-induced increased SA was also positively associated with changes in the amplitude of low frequency fluctuations within the Cg, a measure of spontaneous neuronal activity. Characterizing the distinct brain circuit and behavior changes associated with different facets of addiction increases our understanding of OUD and may provide insight into addiction prevention and treatment.

Nicotine addiction: Translational insights from circuit neuroscience

Contemporary neuroscience aims to understand how neuronal activity produces internal processes and observable behavioral states. This aim crucially depends on systems-level, circuit-based analyses of the working brain, as behavioral states arise from information flow and connectivity within and between discrete and overlapping brain regions, forming circuits and networks. Functional magnetic resonance imaging (fMRI), offers a key to advance circuit neuroscience; fMRI measures inter and intra- regional circuits at behaviorally relevant spatial-temporal resolution. Herein, we argue that cross-sectional observations in human populations can be best understood via mechanistic and causal insights derived from brain circuitry obtained from preclinical fMRI models. Using nicotine addiction as an exemplar of a circuit-based substance use disorder, we review fMRI-based observations of a circuit that was first shown to be disrupted among human smokers and was recently replicated in rodent models of nicotine dependence. Next, we discuss circuits that predispose to nicotine dependence severity and their interaction with circuits that change as a result of chronic nicotine administration using a rodent model of dependence. Data from both clinical and preclinical fMRI experiments argue for the utility of fMRI studies in translation and reverse translation of a circuit-based understanding of brain disease states. We conclude by discussing the future of circuit neuroscience and functional neuroimaging as an essential bridge between animal models and human populations to the understanding of brain function in health and disease.

Cascade Screening for Familial Hypercholesterolemia in South Africa: The Wits FIND-FH Program

OBJECTIVE

Due to gene founder effects, familial hypercholesterolemia (FH) has a prevalence of ≈1:80 in populations of Afrikaner ancestry and is a major contributor to premature atherosclerotic cardiovascular disease in South Africans of Jewish and Indian descent. No systematic program exists to identify these families. Furthermore, information regarding FH prevalence in Black Africans is sparse. The Wits FIND-FH program was initiated in late 2016 to address these issues. Approach and Results: Based on index subjects with definite or probable FH, first-degree relatives were contacted, informed consent obtained, and targeted medical history, physical examination, and blood samples collected. In patients with likely FH using the Simon Broome criteria, DNA analysis for LDLR (low-density lipoprotein receptor), APOB (apolipoprotein B), PCSK9 (proprotein convertase subtilisin/kexin type 9), and LDLRAP1 (LDLR adaptor protein 1) variants was analyzed by next-generation sequencing. Of the initial 700 subjects screened of whom 295 (42%) were index cases, 479 (68.4%) were clinically diagnosed with probable or definite FH. Genetic analysis confirmed 285 of 479 (59.5%) as having variants consistent with FH. Three subjects met the clinical diagnosis for homozygous FH, but DNA analysis revealed a further 34 patients, including 4 Black African subjects, with ≥2 FH-causing variants.

CONCLUSIONS

Using phenotype cascade screening, the Wits FIND-FH program has screened an average of 30 subjects monthly of whom 68% had a clinical diagnosis of FH with ≈60% genetically confirmed. The program is identifying a small but growing number of Black South Africans with FH. Interestingly, 37 subjects (7.7%) who underwent DNA testing were found to have ≥2 FH-causing variants.

Nicotine dependence (trait) and acute nicotinic stimulation (state) modulate attention but not inhibitory control: converging fMRI evidence from Go-Nogo and Flanker tasks

Cognitive deficits during nicotine withdrawal may contribute to smoking relapse. However, interacting effects of chronic nicotine dependence and acute nicotine withdrawal on cognitive control are poorly understood. Here we examine the effects of nicotine dependence (trait; smokers (n = 24) vs. non-smoking controls; n = 20) and acute nicotinic stimulation (state; administration of nicotine and varenicline, two FDA-approved smoking cessation aids, during abstinence), on two well-established tests of inhibitory control, the Go-Nogo task and the Flanker task, during fMRI scanning. We compared performance and neural responses between these four pharmacological manipulations in a double-blind, placebo-controlled crossover design. As expected, performance in both tasks was modulated by nicotine dependence, abstinence, and pharmacological manipulation. However, effects were driven entirely by conditions that required less inhibitory control. When demand for inhibitory control was high, abstinent smokers showed no deficits. By contrast, acutely abstinent smokers showed performance deficits in easier conditions and missed more trials. Go-Nogo fMRI results showed decreased inhibition-related neural activity in right anterior insula and right putamen in smokers and decreased dorsal anterior cingulate cortex activity on nicotine across groups. No effects were found on inhibition-related activity during the Flanker task or on error-related activity in either task. Given robust nicotinic effects on physiology and behavioral deficits in attention, we are confident that pharmacological manipulations were effective. Thus findings fit a recent proposal that abstinent smokers show decreased ability to divert cognitive resources at low or intermediate cognitive demand, while performance at high cognitive demand remains relatively unaffected, suggesting a primary attentional deficit during acute abstinence.

Comparison of Low-Density Lipoprotein Cholesterol Assessment by Martin/Hopkins Estimation, Friedewald Estimation, and Preparative Ultracentrifugation: Insights From the FOURIER Trial

Importance

Recent studies have shown that Friedewald underestimates low-density lipoprotein cholesterol (LDL-C) at lower levels, which could result in undertreatment of high-risk patients. A novel method (Martin/Hopkins) using a patient-specific conversion factor provides more accurate LDL-C levels. However, this method has not been tested in proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor-treated patients.

Objective

To investigate accuracy of 2 different methods for estimating LDL-C levels (Martin/Hopkins and Friedewald) compared with gold standard preparative ultracentrifugation (PUC) in patients with low LDL-C levels in the Further Cardiovascular Outcomes Research With PCSK9 Inhibition in Patients With Elevated Risk (FOURIER) trial.

Design, Setting, and Participants

The FOURIER trial was a randomized clinical trial of evolocumab vs placebo added to statin therapy in 27 564 patients with stable atherosclerotic cardiovascular disease. The patients' LDL-C levels were assessed at baseline, 4 weeks, 12 weeks, 24 weeks, and every 24 weeks thereafter, and measured directly by PUC when the level was less than 40 mg/dL per the Friedewald method (calculated as non-HDL-C level - triglycerides/5). In the Martin/Hopkins method, patient-specific ratios of triglycerides to very low-density lipoprotein cholesterol (VLDL-C) ratios were determined and used to estimate VLDL-C, which was subtracted from the non-HDL-C level to obtain the LDL-C level.

Main Outcomes and Measures

Low-density lipoprotein cholesterol calculated by the Friedewald and Martin/Hopkins methods, with PUC as the reference method.

Results

For this analysis, the mean (SD) age was 62.7 (9.0) years; 2885 of the 12 742 patients were women (22.6%). A total of 56 624 observations from 12 742 patients had Friedewald, Martin/Hopkins, and PUC LDL-C measurements. The median difference from PUC LDL-C levels for Martin/Hopkins LDL-C levels was -2 mg/dL (interquartile range [IQR], -4 to 1 mg/dL) and for Friedewald LDL-C levels was -4 mg/dL (IQR, -8 to -1 mg/dL; P < .001). Overall, 22.9% of Martin/Hopkins LDL-C values were more than 5 mg/dL different than PUC values, and 2.6% were more than 10 mg/dL different than PUC levels. These were significantly less than respective proportions with Friedewald estimation (40.1% and 13.3%; P < .001), mainly because of underestimation by the Friedewald method. The correlation with PUC LDL-C was significantly higher for Martin/Hopkins vs Friedewald (ρ, 0.918 [95% CI 0.916-0.919] vs ρ, 0.867 [0.865-0.869], P < .001).

Conclusions and Relevance

In patients achieving low LDL-C with PCSK9 inhibition, the Martin/Hopkins method for LDL-C estimation more closely approximates gold standard PUC than Friedewald estimation does. The Martin/Hopkins method may prevent undertreatment because of LDL-C underestimation by the Friedewald method.

Trial Registration

ClinicalTrials.gov Identifier: NCT01764633.

MicroRNAs: New Therapeutic Targets for Familial Hypercholesterolemia?

Familial hypercholesterolemia (FH) is the most common inherited form of dyslipidemia and a major cause of premature cardiovascular disease. Management of FH mainly relies on the efficiency of treatments that reduce plasma low-density lipoprotein (LDL) cholesterol (LDL-C) concentrations. MicroRNAs (miRs) have been suggested as emerging regulators of plasma LDL-C concentrations. Notably, there is evidence showing that miRs can regulate the post-transcriptional expression of genes involved in the pathogenesis of FH, including LDLR, APOB, PCSK9, and LDLRAP1. In addition, many miRs are located in genomic loci associated with abnormal levels of circulating lipids and lipoproteins in human plasma. The strong regulatory effects of miRs on the expression of FH-associated genes support of the notion that manipulation of miRs might serve as a potential novel therapeutic approach. The present review describes miRs-targeting FH-associated genes that could be used as potential therapeutic targets in patients with FH or other severe dyslipidemias.

Adverse effects of statin therapy: perception vs. the evidence - focus on glucose homeostasis, cognitive, renal and hepatic function, haemorrhagic stroke and cataract

Aims

To objectively appraise evidence for possible adverse effects of long-term statin therapy on glucose homeostasis, cognitive, renal and hepatic function, and risk for haemorrhagic stroke or cataract.

Methods and results

A literature search covering 2000-2017 was performed. The Panel critically appraised the data and agreed by consensus on the categorization of reported adverse effects. Randomized controlled trials (RCTs) and genetic studies show that statin therapy is associated with a modest increase in the risk of new-onset diabetes mellitus (about one per thousand patient-years), generally defined by laboratory findings (glycated haemoglobin ≥6.5); this risk is significantly higher in the metabolic syndrome or prediabetes. Statin treatment does not adversely affect cognitive function, even at very low levels of low-density lipoprotein cholesterol and is not associated with clinically significant deterioration of renal function, or development of cataract. Transient increases in liver enzymes occur in 0.5-2% of patients taking statins but are not clinically relevant; idiosyncratic liver injury due to statins is very rare and causality difficult to prove. The evidence base does not support an increased risk of haemorrhagic stroke in individuals without cerebrovascular disease; a small increase in risk was suggested by the Stroke Prevention by Aggressive Reduction of Cholesterol Levels study in subjects with prior stroke but has not been confirmed in the substantive evidence base of RCTs, cohort studies and case-control studies.

Conclusion

Long-term statin treatment is remarkably safe with a low risk of clinically relevant adverse effects as defined above; statin-associated muscle symptoms were discussed in a previous Consensus Statement. Importantly, the established cardiovascular benefits of statin therapy far outweigh the risk of adverse effects.

Long-term treatment with evolocumab added to conventional drug therapy, with or without apheresis, in patients with homozygous familial hypercholesterolaemia: an interim subset analysis of the open-label TAUSSIG study

BACKGROUND

Homozygous familial hypercholesterolaemia is a genetic disorder characterised by substantially raised LDL cholesterol, reduced LDL receptor function, xanthomas, and cardiovascular disease before age 20 years. Conventional therapy is with statins, ezetimibe, and apheresis. We aimed to assess the long-term safety and efficacy of the proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor evolocumab in a subset of patients with homozygous familial hypercholesterolaemia enrolled in an open-label, non-randomised phase 3 trial.

METHODS

In this interim subset analysis of the TAUSSIG study, which was undertaken at 35 sites in 17 countries, we included patients aged 12 years or older with homozygous familial hypercholesterolaemia who were on stable LDL cholesterol-lowering therapy for at least 4 weeks; all patients received evolocumab 420 mg subcutaneously monthly, or if on apheresis every 2 weeks. Dosing could be increased to every 2 weeks after 12 weeks in patients not on apheresis. The primary outcome of the TAUSSIG study was treatment-emergent adverse events; secondary outcomes were the effects of evolocumab on LDL cholesterol and other lipids. We analysed patients on an intention-to-treat basis, and all statistical comparisons were done post hoc in this interim analysis. The TAUSSIG study is registered with ClinicalTrials.gov, number NCT01624142, and is ongoing.

FINDINGS

106 patients were included in this analysis, 34 receiving apheresis at study entry and 14 younger than 18 years. The first patient was enrolled on June 28, 2012, and the cutoff date for the analysis was Aug 13, 2015; mean follow-up was 1·7 years (SD 0·63). After 12 weeks, mean LDL cholesterol decreased from baseline by 20·6% (SD 24·4; mean absolute decrease 1·50 mmol/L [SD 1·92]); these reductions were maintained at week 48. 47 of 72 patients not on apheresis at study entry increased evolocumab dosing to every 2 weeks, with an additional mean reduction in LDL cholesterol of 8·3% (SD 13·0; mean absolute decrease 0·77 mmol/L [SD 1·38]; p=0·0001). In a post-hoc analysis, mean reductions in LDL cholesterol in patients on apheresis were significant at week 12 (p=0·0012) and week 48 (p=0·0032), and did not differ from reductions achieved in patients not on apheresis (p=0·38 at week 12 and p=0·09 at week 48). We noted a small reduction (median -7·7% [IQR -21·6 to 6·8]) in lipoprotein(a) at week 12 (p=0·0015), with some additional reduction at week 48 (-11·9% [-28·0 to 0·0]; p<0·0001). HDL cholesterol was increased by a mean of 7·6% (SD 18·1) at week 12 (p<0·0001) and 7·6% (SD 20·6) at week 48 (p=0·0007). Evolocumab was well tolerated; 82 (77%) patients reported treatment-emergent adverse events, which were mostly minor. The most common were nasopharyngitis (14 patients [13%]), influenza (13 [12%]), headache (11 [10%]), and upper respiratory tract infection (11 [10%]). Serious adverse events occurred in 18 (17%) patients, with the most common being cardiovascular events (four patients [4%]). There were no deaths and four positively adjudicated cardiovascular events, one (3%) among patients on apheresis and three (4%) among patients who did not receive apheresis.

INTERPRETATION

Our interim results suggest that evolocumab is an effective additional option to reduce LDL cholesterol in patients with homozygous familial hypercholesterolaemia, with or without apheresis.

FUNDING

Amgen.

Proprotein Convertase Subtilisin/kexin Type 9 Inhibitors in Clinical Practice: A Focused Update

This article provides an updated review of the LDL-cholesterol efficacy, safety, and cardiovascular benefits of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors. It focuses on evidence from numerous clinical trials and provides clinicians with a basis for understanding, assessing, and selecting these agents for clinical practice. It also provides some perspective on other potential agents in development that target PCSK9.

Lipid-Lowering Drug Therapy for CVD Prevention: Looking into the Future

Over the past three decades, statins have become first-line treatment for reducing LDL cholesterol (LDL-C) and cardiovascular disease (CVD). They have provided a clear, robust, and reproducible relationship between the absolute LDL-C reduction and the decrease in CVD; every 1 mmol/L (~40 mg/dL) in LDL-C reduction results in a 22 % decrease in CVD events. This relationship has recently been extended to reduction in LDL-C with a non-statin, ezetimibe, on top of statin therapy, further consolidating LDL-C as the cornerstone in CVD risk reduction. Despite these two effective and safe LDL-C-lowering drugs, there remains a need for additional drugs to reduce LDL-C, the focus of this review which covers agents which produce sufficient LDL-C reduction to potentially help address this unmet need and are either recently approved or currently in clinical trials.

PCSK9 inhibition-mediated reduction in Lp(a) with evolocumab: an analysis of 10 clinical trials and the LDL receptor's role

Lipoprotein (a) [Lp(a)] is independently associated with CVD risk. Evolocumab, a monoclonal antibody (mAb) to proprotein convertase subtilisin/kexin type 9 (PCSK9), decreases Lp(a). The potential mechanisms were assessed. A pooled analysis of Lp(a) and LDL cholesterol (LDL-C) in 3,278 patients from 10 clinical trials (eight phase 2/3; two extensions) was conducted. Within each parent study, biweekly and monthly doses of evolocumab statistically significantly reduced Lp(a) at week 12 versus control (P < 0.001 within each study); pooled median (quartile 1, quartile 3) percent reductions were 24.7% (40.0, 3.6) and 21.7% (39.9, 4.2), respectively. Reductions were maintained through week 52 of the open-label extension, and correlated with LDL-C reductions [with and without correction for Lp(a)-cholesterol] at both time points (P < 0.0001). The effect of LDL and LDL receptor (LDLR) availability on Lp(a) cell-association was measured in HepG2 cells: cell-associated LDL fluorescence was reversed by unlabeled LDL and Lp(a). Lp(a) cell-association was reduced by coincubation with LDL and PCSK9 and reversed by adding PCSK9 mAb. These studies support that reductions in Lp(a) with PCSK9 inhibition are partly due to increased LDLR-mediated uptake. In most situations, Lp(a) appears to compete poorly with LDL for LDLR binding and internalization, but when LDLR expression is increased with evolocumab, particularly in the setting of low circulating LDL, Lp(a) is reduced.

Efficacy and Tolerability of Evolocumab vs Ezetimibe in Patients With Muscle-Related Statin Intolerance: The GAUSS-3 Randomized Clinical Trial

IMPORTANCE

Muscle-related statin intolerance is reported by 5% to 20% of patients.

OBJECTIVE

To identify patients with muscle symptoms confirmed by statin rechallenge and compare lipid-lowering efficacy for 2 nonstatin therapies, ezetimibe and evolocumab.

DESIGN, SETTING, AND PARTICIPANTS

Two-stage randomized clinical trial including 511 adult patients with uncontrolled low-density lipoprotein cholesterol (LDL-C) levels and history of intolerance to 2 or more statins enrolled in 2013 and 2014 globally. Phase A used a 24-week crossover procedure with atorvastatin or placebo to identify patients having symptoms only with atorvastatin but not placebo. In phase B, after a 2-week washout, patients were randomized to ezetimibe or evolocumab for 24 weeks.

INTERVENTIONS

Phase A: atorvastatin (20 mg) vs placebo. Phase B: randomization 2:1 to subcutaneous evolocumab (420 mg monthly) or oral ezetimibe (10 mg daily).

MAIN OUTCOME AND MEASURES

Coprimary end points were the mean percent change in LDL-C level from baseline to the mean of weeks 22 and 24 levels and from baseline to week 24 levels.

RESULTS

Of the 491 patients who entered phase A (mean age, 60.7 [SD, 10.2] years; 246 women [50.1%]; 170 with coronary heart disease [34.6%]; entry mean LDL-C level, 212.3 [SD, 67.9] mg/dL), muscle symptoms occurred in 209 of 491 (42.6%) while taking atorvastatin but not while taking placebo. Of these, 199 entered phase B, along with 19 who proceeded directly to phase B for elevated creatine kinase (N = 218, with 73 randomized to ezetimibe and 145 to evolocumab; entry mean LDL-C level, 219.9 [SD, 72] mg/dL). For the mean of weeks 22 and 24, LDL-C level with ezetimibe was 183.0 mg/dL; mean percent LDL-C change, -16.7% (95% CI, -20.5% to -12.9%), absolute change, -31.0 mg/dL and with evolocumab was 103.6 mg/dL; mean percent change, -54.5% (95% CI, -57.2% to -51.8%); absolute change, -106.8 mg/dL (P < .001). LDL-C level at week 24 with ezetimibe was 181.5 mg/dL; mean percent change, -16.7% (95% CI, -20.8% to -12.5%); absolute change, -31.2 mg/dL and with evolocumab was 104.1 mg/dL; mean percent change, -52.8% (95% CI, -55.8% to -49.8%); absolute change, -102.9 mg/dL (P < .001). For the mean of weeks 22 and 24, between-group difference in LDL-C was -37.8%; absolute difference, -75.8 mg/dL. For week 24, between-group difference in LDL-C was -36.1%; absolute difference, -71.7 mg/dL. Muscle symptoms were reported in 28.8% of ezetimibe-treated patients and 20.7% of evolocumab-treated patients (log-rank P = .17). Active study drug was stopped for muscle symptoms in 5 of 73 ezetimibe-treated patients (6.8%) and 1 of 145 evolocumab-treated patients (0.7%).

CONCLUSIONS AND RELEVANCE

Among patients with statin intolerance related to muscle-related adverse effects, the use of evolocumab compared with ezetimibe resulted in a significantly greater reduction in LDL-C levels after 24 weeks. Further studies are needed to assess long-term efficacy and safety.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01984424.

The Central Role of Proprotein Convertase Subtilisin/Kexin Type 9 in Septic Pathogen Lipid Transport and Clearance

Microbial cell walls contain pathogenic lipids, including LPS in gram-negative bacteria, lipoteichoic acid in gram-positive bacteria, and phospholipomannan in fungi. These pathogen lipids are major ligands for innate immune receptors and figure prominently in triggering the septic inflammatory response. Alternatively, pathogen lipids can be cleared and inactivated, thus limiting the inflammatory response. Accordingly, biological mechanisms for sequestering and clearing pathogen lipids from the circulation have evolved. Pathogen lipids released into the circulation are initially bound by transfer proteins, notably LPS binding protein and phospholipid transfer protein, and incorporated into high-density lipoprotein particles. Next, LPS binding protein, phospholipid transfer protein, and other transfer proteins transfer these lipids to ApoB-containing lipoproteins, including low-density (LDL) and very-low-density lipoproteins and chylomicrons. Pathogen lipids within these lipoproteins and their remnants are then cleared from the circulation by the liver. Hepatic clearance involves the LDL receptor (LDLR) and possibly other receptors. Once absorbed by the liver, these lipids are then excreted in the bile. Recent evidence suggests pathogen lipid clearance can be modulated. Importantly, reduced proprotein convertase subtilisin/kexin type 9 activity increases recycling of the LDLR and thereby increases LDLR on the surface of hepatocytes, which increases clearance by the liver of pathogen lipids transported in LDL. Increased pathogen lipid clearance, which can be achieved by inhibiting proprotein convertase subtilisin/kexin type 9, may decrease the systemic inflammatory response to sepsis and improve clinical outcomes.

What role will proprotein convertase subtilisin/kexin type 9 inhibitors play in hyperlipidemia management?

PURPOSE OF REVIEW

This article summarizes the role that the recently approved proprotein convertase subtilisin/kexin type 9 (PCSK9) monoclonal antibodies (mAbs) will play in LDL cholesterol management.

RECENT FINDINGS

The discovery of PCSK9 in 2003 and its association with a rare form of autosomal-dominant hypercholesterolemia quickly led to the understanding of the role of circulating PCSK9 in regulating the recycling of the LDL receptor and LDL cholesterol (LDL-C) and impact on cardiovascular disease. Development of monoclonal antibodies that bind and inhibit PCSK9 entered clinical development in late 2009 and demonstrated substantial LDL-C reductions as monotherapy, added to statins, in heterozygous familial hypercholesterolemia and patients intolerant of statins. Large and comprehensive trials over the last 5 years also indicated good tolerability and safety and resulted in the 2015 regulatory approval in the USA and Europe for the marketing of two mAbs, evolocumab and alirocumab, for the treatment of LDL-C.

SUMMARY

The background, clinical trials and approved indications for the current PCSK9 inhibitors are reviewed along with their likely role in the management of LDL-C and cardiovascular disease prevention.

Comparison of PCSK9 Inhibitor Evolocumab vs Ezetimibe in Statin-Intolerant Patients: Design of the Goal Achievement After Utilizing an Anti-PCSK9 Antibody in Statin-Intolerant Subjects 3 (GAUSS-3) Trial

Statins are the accepted standard for lowering low-density lipoprotein cholesterol (LDL-C). However, 5% to 10% of statin-treated patients report intolerance, mostly due to muscle-related adverse effects. Challenges exist to objective identification of statin-intolerant patients. Evolocumab is a monoclonal antibody that binds proprotein convertase subtilisin/kexin type 9 (PCSK9), resulting in marked LDL-C reduction. We report the design of Goal Achievement After Utilizing an Anti-PCSK9 Antibody in Statin-Intolerant Subjects 3 (GAUSS-3), a phase 3, multicenter, randomized, double-blind, ezetimibe-controlled study to compare effectiveness of 24 weeks of evolocumab 420 mg monthly vs ezetimibe 10 mg daily in hypercholesterolemic patients unable to tolerate an effective statin dose. The study incorporates a novel atorvastatin-controlled, double-blind, crossover phase to objectively identify statin intolerance. Eligible patients had LDL-C above the National Cholesterol Education Project Adult Treatment Panel III target level for the appropriate coronary heart disease risk category and were unable to tolerate ≥3 statins or 2 statins (one of which was atorvastatin ≤10 mg/d) or had a history of marked creatine kinase elevation accompanied by muscle symptoms while on 1 statin. This trial has 2 co-primary endpoints: mean percent change from baseline in LDL-C at weeks 22 and 24 and percent change from baseline in LDL-C at week 24. Key secondary efficacy endpoints include change from baseline in LDL-C, percent of patients attaining LDL-C <70 mg/dL (1.81 mmol/L), and percent change from baseline in total cholesterol, non-high-density lipoprotein cholesterol, and apolipoprotein B. Recruitment of 511 patients was completed on November 28, 2014.

Delayed emergence of methamphetamine's enhanced cardiovascular effects in nonhuman primates during protracted methamphetamine abstinence

BACKGROUND

Methamphetamine abuse is linked with brain abnormalities, but its peripheral effects constitute an integral aspect of long-term methamphetamine use.

METHODS

Eight male rhesus monkeys with long histories of intravenous methamphetamine self-administration were evaluated 1 day, and 1, 4, 12, 26, and 52 weeks after their last methamphetamine self-administration session. On test days, isoflurane-anesthetized animals received a 0.35 mg/kg IV methamphetamine challenge. A control group consisted of 10 age and gender matched drug naïve monkeys. Cardiovascular responses to methamphetamine were followed for 2.5h. Echocardiograms were acquired at 3 and 12 months of abstinence and in the control animals.

RESULTS

No pre-methamphetamine baseline differences existed among 7 physiological measures across all conditions and controls. As expected, methamphetamine increased heart rate and blood pressure in controls. However, immediately following the self-administration period, the blood pressure response to methamphetamine challenge was reduced when compared to control monkeys. The peak and 150-min average heart rate increases, as well as peak blood pressure increases following methamphetamine were significantly elevated between weeks 12 to 26 of abstinence. These data indicate the development of tolerance followed by sensitization to methamphetamine cardiovascular effects. Echocardiography demonstrated decreased left ventricular ejection fraction and cardiac output at 3 months of abstinence. Importantly, both cardiovascular sensitization and cardiotoxicity appeared to be reversible as they returned toward control group levels after 1 year of abstinence.

CONCLUSIONS

Enhanced cardiovascular effects may occur after prolonged abstinence in addicts relapsing to methamphetamine and may underlie clinically reported acute cardiotoxic events.

Efficacy and safety of evolocumab in reducing lipids and cardiovascular events

BACKGROUND

Evolocumab, a monoclonal antibody that inhibits proprotein convertase subtilisin-kexin type 9 (PCSK9), significantly reduced low-density lipoprotein (LDL) cholesterol levels in short-term studies. We conducted two extension studies to obtain longer-term data.

METHODS

In two open-label, randomized trials, we enrolled 4465 patients who had completed 1 of 12 phase 2 or 3 studies ("parent trials") of evolocumab. Regardless of study-group assignments in the parent trials, eligible patients were randomly assigned in a 2:1 ratio to receive either evolocumab (140 mg every 2 weeks or 420 mg monthly) plus standard therapy or standard therapy alone. Patients were followed for a median of 11.1 months with assessment of lipid levels, safety, and (as a prespecified exploratory analysis) adjudicated cardiovascular events including death, myocardial infarction, unstable angina, coronary revascularization, stroke, transient ischemic attack, and heart failure. Data from the two trials were combined.

RESULTS

As compared with standard therapy alone, evolocumab reduced the level of LDL cholesterol by 61%, from a median of 120 mg per deciliter to 48 mg per deciliter (P<0.001). Most adverse events occurred with similar frequency in the two groups, although neurocognitive events were reported more frequently in the evolocumab group. The risk of adverse events, including neurocognitive events, did not vary significantly according to the achieved level of LDL cholesterol. The rate of cardiovascular events at 1 year was reduced from 2.18% in the standard-therapy group to 0.95% in the evolocumab group (hazard ratio in the evolocumab group, 0.47; 95% confidence interval, 0.28 to 0.78; P=0.003).

CONCLUSIONS

During approximately 1 year of therapy, the use of evolocumab plus standard therapy, as compared with standard therapy alone, significantly reduced LDL cholesterol levels and reduced the incidence of cardiovascular events in a prespecified but exploratory analysis. (Funded by Amgen; OSLER-1 and OSLER-2 ClinicalTrials.gov numbers, NCT01439880 and NCT01854918.).

PCSK9 inhibition with evolocumab (AMG 145) in heterozygous familial hypercholesterolaemia (RUTHERFORD-2): a randomised, double-blind, placebo-controlled trial

BACKGROUND

Heterozygous familial hypercholesterolaemia is characterised by low cellular uptake of LDL cholesterol, increased plasma LDL cholesterol concentrations, and premature cardiovascular disease. Despite intensive statin therapy, with or without ezetimibe, many patients are unable to achieve recommended target levels of LDL cholesterol. We investigated the effect of PCSK9 inhibition with evolocumab (AMG 145) on LDL cholesterol in patients with this disorder.

METHODS

This multicentre, randomised, double-blind, placebo-controlled trial was undertaken at 39 sites (most of which were specialised lipid clinics, mainly attached to academic institutions) in Australia, Asia, Europe, New Zealand, North America, and South Africa between Feb 7 and Dec 19, 2013. 331 eligible patients (18-80 years of age), who met clinical criteria for heterozygous familial hypercholesterolaemia and were on stable lipid-lowering therapy for at least 4 weeks, with a fasting LDL cholesterol concentration of 2·6 mmol/L or higher, were randomly allocated in a 2:2:1:1 ratio to receive subcutaneous evolocumab 140 mg every 2 weeks, evolocumab 420 mg monthly, or subcutaneous placebo every 2 weeks or monthly for 12 weeks. Randomisation was computer generated by the study sponsor, implemented by a computerised voice interactive system, and stratified by LDL cholesterol concentration at screening (higher or lower than 4·1 mmol/L) and by baseline ezetimibe use (yes/no). Patients, study personnel, investigators, and Amgen study staff were masked to treatment assignments within dosing frequency groups. The coprimary endpoints were percentage change from baseline in LDL cholesterol at week 12 and at the mean of weeks 10 and 12, analysed by intention-to-treat. This trial is registered with ClinicalTrials.gov, number NCT01763918.

FINDINGS

Of 415 screened patients, 331 were eligible and were randomly assigned to the four treatment groups: evolocumab 140 mg every 2 weeks (n=111), evolocumab 420 mg monthly (n=110), placebo every 2 weeks (n=55), or placebo monthly (n=55). 329 patients received at least one dose of study drug. Compared with placebo, evolocumab at both dosing schedules led to a significant reduction in mean LDL cholesterol at week 12 (every-2-weeks dose: 59·2% reduction [95% CI 53·4-65·1], monthly dose: 61·3% reduction [53·6-69·0]; both p<0·0001) and at the mean of weeks 10 and 12 (60·2% reduction [95% CI 54·5-65·8] and 65·6% reduction [59·8-71·3]; both p<0·0001). Evolocumab was well tolerated, with rates of adverse events similar to placebo. The most common adverse events occurring more frequently in the evolocumab-treated patients than in the placebo groups were nasopharyngitis (in 19 patients [9%] vs five [5%] in the placebo group) and muscle-related adverse events (ten patients [5%] vs 1 [1%]).

INTERPRETATION

In patients with heterozygous familial hypercholesterolaemia, evolocumab administered either 140 mg every 2 weeks or 420 mg monthly was well tolerated and yielded similar and rapid 60% reductions in LDL cholesterol compared with placebo.

FUNDING

Amgen Inc.

Inhibition of PCSK9 with evolocumab in homozygous familial hypercholesterolaemia (TESLA Part B): a randomised, double-blind, placebo-controlled trial

BACKGROUND

Homozygous familial hypercholesterolaemia is a rare, serious disorder caused by very low or absent plasma clearance of LDL, substantially raised LDL cholesterol, and accelerated development of cardiovascular disease. Conventional lipid-lowering treatments are modestly effective. Evolocumab, a monoclonal antibody to proprotein convertase subtilisin/kexin type 9 (PCSK9), reduced LDL cholesterol by 16% in a pilot study. We now report results with evolocumab in a randomised, double-blind, placebo-controlled phase 3 trial.

METHODS

This randomised, double-blind, placebo-controlled phase 3 trial was undertaken at 17 sites in ten countries in North America, Europe, the Middle East, and South Africa. 50 eligible patients (aged ≥12 years) with homozygous familial hypercholesterolaemia, on stable lipid-regulating therapy for at least 4 weeks, and not receiving lipoprotein apheresis, were randomly allocated by a computer-generated randomisation sequence in a 2:1 ratio to receive subcutaneous evolocumab 420 mg or placebo every 4 weeks for 12 weeks. Randomisation was stratified by LDL cholesterol at screening (<11 mmol/L or ≥11 mmol/L) and implemented by a computerised interactive voice-response system. Patients, study personnel, and the funder were masked to treatment and to the efficacy results by the central laboratory not returning LDL cholesterol or any lipid results to the clinical sites after the baseline visit. The primary endpoint was percentage change in ultracentrifugation LDL cholesterol from baseline at week 12 compared with placebo, analysed by intention-to-treat. This trial is registered with ClinicalTrials.gov, number NCT01588496.

FINDINGS

Of the 50 eligible patients randomly assigned to the two treatment groups, 49 actually received the study drug and completed the study (16 in the placebo group and 33 in the evolocumab group). Compared with placebo, evolocumab significantly reduced ultracentrifugation LDL cholesterol at 12 weeks by 30·9% (95% CI -43·9% to -18·0%; p<0·0001). Treatment-emergent adverse events occurred in ten (63%) of 16 patients in the placebo group and 12 (36%) of 33 in the evolocumab group. No serious clinical or laboratory adverse events occurred, and no anti-evolocumab antibody development was detected during the study.

INTERPRETATION

In patients with homozygous familial hypercholesterolaemia receiving stable background lipid-lowering treatment and not on apheresis, evolocumab 420 mg administered every 4 weeks was well tolerated and significantly reduced LDL cholesterol compared with placebo.

FUNDING

Amgen Inc.

New therapies for reducing low-density lipoprotein cholesterol

Although the past 4 decades have been the most productive in transitioning from an low-density lipoprotein cholesterol (LDL-C) hypothesis to demonstration of clinical benefit, cardiovascular disease remains a major cause of mortality and morbidity. It is fortunate that most of the effective lipid-lowering drugs, the statins, have become generic and inexpensive. However, there remains a large unmet medical need for new and effective agents that are also well tolerated and safe, especially for patients unable to either tolerate statins or achieve optimal LDL-C on current therapies. It is likely that the agents discussed in this review will fill that need.

Reduction of low-density lipoprotein cholesterol by monoclonal antibody inhibition of PCSK9

Published phase I and II trials with two fully human monoclonal antibodies to PCSK9 have provided comprehensive evidence that inhibiting PCSK9 is a very effective method to reduce low-density lipoprotein cholesterol (LDL-C). In all populations studied so far, whether on statins or LDL-C-reducing diet alone, with or without a genetic defect in the LDL receptor, and in subjects intolerant to statins, the LDL-C reductions have been large and consistent. Even the most efficacious statin, rosuvastatin, at its highest dose has not achieved such reductions. The clinical trials have established that monoclonal antibody therapy targeted to PCSK9 may be administered subcutaneously every two or four weeks. Current data suggest these drugs will provide an effective therapeutic option for LDL-C reduction and that, if proven safe in phase III trials, they will be as important to LDL-C control, and likely to cardiovascular disease risk reduction, as statins have been over the past three decades.

Targeting LDL: is lower better and is it safe?

Low density lipoprotein cholesterol (LDL-C) is one of the most validated targets in clinical medicine. Large randomized, outcome trials have demonstrated a clear relationship between reducing LDL-C and cardiovascular disease (CVD) risk, which has been maintained to LDL-C levels of <1.8 mmol/L. To assess the benefit of even lower LDL-C it is important to recognize that CVD risk reduction is related to absolute reduction in LDL-C, not to percent change. Furthermore measurement of LDL-C is also critical as recent studies show the Friedewald calculation significantly underestimates true LDL-C values <1.8 mmol/L, distorting the relationship with CVD risk reduction. Discussion of potential harm from low, or lower, LDL-C has centered on cancer, hemorrhagic stroke, and violent death, but there is little evidence from outcome trials to show a relationship with low LDL-C. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors which will reduce LDL-C well below 1.3 mmol/L, will likely provide the clearest answer to both the question of efficacy and safety of low LDL-C within the next few years.

A 52-week placebo-controlled trial of evolocumab in hyperlipidemia

BACKGROUND

Evolocumab, a monoclonal antibody that inhibits proprotein convertase subtilisin/kexin type 9 (PCSK9), significantly reduced low-density lipoprotein (LDL) cholesterol levels in phase 2 studies. We conducted a phase 3 trial to evaluate the safety and efficacy of 52 weeks of treatment with evolocumab.

METHODS

We stratified patients with hyperlipidemia according to the risk categories outlined by the Adult Treatment Panel III of the National Cholesterol Education Program. On the basis of this classification, patients were started on background lipid-lowering therapy with diet alone or diet plus atorvastatin at a dose of 10 mg daily, atorvastatin at a dose of 80 mg daily, or atorvastatin at a dose of 80 mg daily plus ezetimibe at a dose of 10 mg daily, for a run-in period of 4 to 12 weeks. Patients with an LDL cholesterol level of 75 mg per deciliter (1.9 mmol per liter) or higher were then randomly assigned in a 2:1 ratio to receive either evolocumab (420 mg) or placebo every 4 weeks. The primary end point was the percent change from baseline in LDL cholesterol, as measured by means of ultracentrifugation, at week 52.

RESULTS

Among the 901 patients included in the primary analysis, the overall least-squares mean (±SE) reduction in LDL cholesterol from baseline in the evolocumab group, taking into account the change in the placebo group, was 57.0±2.1% (P<0.001). The mean reduction was 55.7±4.2% among patients who underwent background therapy with diet alone, 61.6±2.6% among those who received 10 mg of atorvastatin, 56.8±5.3% among those who received 80 mg of atorvastatin, and 48.5±5.2% among those who received a combination of 80 mg of atorvastatin and 10 mg of ezetimibe (P<0.001 for all comparisons). Evolocumab treatment also significantly reduced levels of apolipoprotein B, non-high-density lipoprotein cholesterol, lipoprotein(a), and triglycerides. The most common adverse events were nasopharyngitis, upper respiratory tract infection, influenza, and back pain.

CONCLUSIONS

At 52 weeks, evolocumab added to diet alone, to low-dose atorvastatin, or to high-dose atorvastatin with or without ezetimibe significantly reduced LDL cholesterol levels in patients with a range of cardiovascular risks. (Funded by Amgen; DESCARTES ClinicalTrials.gov number, NCT01516879.).

Low-density lipoprotein cholesterol reduction by inhibition of PCSK9

PURPOSE OF REVIEW

To review the phase 1 and 2 trials with fully human monoclonal antibodies to proprotein convertase subtilisin/kexin type 9 published in the last 18 months and provide comprehensive data that targeting proprotein convertase subtilisin/kexin type 9 very effectively reduces LDL-cholesterol (LDL-C).

RECENT FINDINGS

The trials studied a number of different populations including patients with LDL receptor defects (heterozygous familial hypercholesterolemia) and non-familial hypercholesterolemia, background statin or diet only treatment, and those intolerant to statins. The LDL-C lowering has been large, consistent and greater than the largest reductions achievable by the most efficacious statins. These subcutaneously administered drugs produce very rapid reductions in LDL-C, maximal in 7 days, with dosing frequency that may be every 2 or 4 weeks. Unexpected, consistent and robust reductions in Lp(a) have also been reported. Based on these short-term trials of 8-12 weeks in over 1500 patients the drugs have been very well tolerated and the emergent safety profile has not identified any specific areas of concern.

SUMMARY

Provided these compounds continue to exhibit an acceptable safety profile in ongoing phase 3 trials they will be as crucial to LDL-C control and reduction of cardiovascular disease, as statins.

Effect of the proprotein convertase subtilisin/kexin 9 monoclonal antibody, AMG 145, in homozygous familial hypercholesterolemia

BACKGROUND

Homozygous familial hypercholesterolemia is a rare, serious disorder with a substantial reduction in low-density lipoprotein (LDL) receptor function, severely elevated LDL cholesterol, cardiovascular disease, and often death in childhood. Response to conventional drug therapies is modest. Monoclonal antibodies to proprotein convertase subtilisin/kexin 9 (PCSK9) reduce LDL cholesterol in heterozygous familial hypercholesterolemia. The effect in homozygous familial hypercholesterolemia is unknown and uncertain. We evaluated the efficacy and safety of AMG 145 in an open-label, single-arm, multicenter, dose-scheduling pilot study in patients with homozygous familial hypercholesterolemia.

METHODS AND RESULTS

Eight patients with LDL receptor-negative or -defective homozygous familial hypercholesterolemia on stable drug therapy were treated with subcutaneous 420 mg AMG 145 every 4 weeks for ≥12 weeks, followed by 420 mg AMG 145 every 2 weeks for an additional 12 weeks. All patients completed both treatment periods. Mean change from baseline in LDL cholesterol at week 12 was -16.5% (range, 5.2% to -43.6%; P=0.0781) and -13.9% (range, 39.9% to -43.3%; P=0.1484) with 4- and 2-week dosing, respectively. No reduction was seen in the 2 receptor-negative patients. Over the treatment periods, mean±SD LDL cholesterol reductions in the 6 LDL receptor-defective patients were 19.3±16% and 26.3±20% with 4- and 2-week dosing, respectively (P=0.0313 for both values), ranging from 4% to 48% with 2-week dosing. No serious side effects were reported.

CONCLUSION

This study demonstrates significant and dose-related LDL cholesterol lowering with a PCSK9 monoclonal antibody in homozygous familial hypercholesterolemia patients with defective LDL receptor activity but no reduction in those who were receptor negative.

Potential of proprotein convertase subtilisin/kexin type 9 based therapeutics

The link between proprotein convertase subtilisin/kexin type 9 (PCSK9) and cholesterol metabolism was established only in 2003 when genetic mapping and positional cloning in patients with autosomal dominant hypercholesterolemia in which linkage to the loci coding for the LDL receptor and apolipoprotein B had been excluded identified the genetic defect missense as mutations in PCSK9, a protein/enzyme previously unknown to be related to lipid metabolism. Laboratory-based investigations confirmed that these were gain-of-function mutations. Further studies in cohorts with low LDL cholesterol (LDLc) levels from large epidemiological cardiovascular studies reported that loss-of-function mutations in PCSK9 were associated with protection from cardiovascular disease. An additional critical observation provided evidence that the interaction of PCSK9 and the LDL receptor was through circulating, not intracellular, PCSK9, which bound to the receptor, and then mediated the recycling of the LDL receptor. These findings established PSCK9 as a potential therapeutic target and resulted in biopharmaceutical companies developing interventions designed to lower LDLc levels. Clinical development programs for monoclonal antibodies against PCSK9 have advanced rapidly with completion of comprehensive phase 1 and 2 trials with both REGN727/SAR236553 (REGN727) and AMG 145, clearly demonstrating substantial reductions in LDLc levels in patients receiving diet alone, low, moderate, and high doses of statins, or statin combined with ezetimibe, and both heterozygous familial hypercholesterolemia and nonfamilial hypercholesterolemia subjects. Concomitant and parallel reductions in the levels of apolipoprotein B and its related lipoproteins, and small but significant increases in HDL cholesterol levels were seen as anticipated. An unanticipated and robust decrease in lipoprotein(a) levels was also noted. Although these trials have been relatively short term, no significant safety issues or target organs of interest have emerged. Larger and much longer phase 3 trials are now in progress to assess the long-term tolerability, safety, and impact on cardiovascular disease events of these very effective LDLc lowering compounds.