Streamlining cardiovascular clinical trials to improve efficiency and generalisability.

Controlled trials provide the most valid determination of the efficacy and safety of an intervention, but large cardiovascular clinical trials have become extremely costly and complex, making it difficult to study many important clinical questions. A critical question, and the main objective of this review, is how trials might be simplified while maintaining randomisation to preserve scientific integrity and unbiased efficacy assessments. Experience with alternative approaches is accumulating, specifically with registry-based randomised controlled trials that make use of data already collected. This approach addresses bias concerns while still capitalising on the benefits and efficiencies of a registry. Several completed or ongoing trials illustrate the feasibility of using registry-based controlled trials to answer important questions relevant to daily clinical practice. Randomised trials within healthcare organisation databases may also represent streamlined solutions for some types of investigations, although data quality (endpoint assessment) is likely to be a greater concern in those settings. These approaches are not without challenges, and issues pertaining to informed consent, blinding, data quality and regulatory standards remain to be fully explored. Collaboration among stakeholders is necessary to achieve standards for data management and analysis, to validate large data sources for use in randomised trials, and to re-evaluate ethical standards to encourage research while also ensuring that patients are protected. The rapidly evolving efforts to streamline cardiovascular clinical trials have the potential to lead to major advances in promoting better care and outcomes for patients with cardiovascular disease.

Electronic health records to facilitate clinical research.

Electronic health records (EHRs) provide opportunities to enhance patient care, embed performance measures in clinical practice, and facilitate clinical research. Concerns have been raised about the increasing recruitment challenges in trials, burdensome and obtrusive data collection, and uncertain generalizability of the results. Leveraging electronic health records to counterbalance these trends is an area of intense interest. The initial applications of electronic health records, as the primary data source is envisioned for observational studies, embedded pragmatic or post-marketing registry-based randomized studies, or comparative effectiveness studies. Advancing this approach to randomized clinical trials, electronic health records may potentially be used to assess study feasibility, to facilitate patient recruitment, and streamline data collection at baseline and follow-up. Ensuring data security and privacy, overcoming the challenges associated with linking diverse systems and maintaining infrastructure for repeat use of high quality data, are some of the challenges associated with using electronic health records in clinical research. Collaboration between academia, industry, regulatory bodies, policy makers, patients, and electronic health record vendors is critical for the greater use of electronic health records in clinical research. This manuscript identifies the key steps required to advance the role of electronic health records in cardiovascular clinical research.

Improving clinical trials for cardiovascular diseases: a position paper from the Cardiovascular Round Table of the European Society of Cardiology.

AIMS: Cardiovascular disease is the most common cause of mortality and morbidity in the world, but the pharmaceutical industry's willingness to invest in this field has declined because of the many challenges involved with bringing new cardiovascular drugs to market, including late-stage failures, escalating regulatory requirements, bureaucracy of the clinical trial business enterprise, and limited patient access after approval. This contrasts with the remaining burden of cardiovascular disease in Europe and in the world. Thus, clinical cardiovascular research needs to adapt to address the impact of these challenges in order to ensure development of new cardiovascular medicines. METHODS AND RESULTS: The present paper is the outcome of a two-day workshop held by the Cardiovascular Round Table of the European Society of Cardiology. We propose strategies to improve development of effective new cardiovascular therapies. These can include (i) the use of biomarkers to describe patients who will benefit from new therapies more precisely, achieving better human target validation; (ii) targeted, mechanism-based approaches to drug development for defined populations; (iii) the use of information technology to simplify data collection and follow-up in clinical trials; (iv) streamlining adverse event collection and reducing monitoring; (v) extended patent protection or limited rapid approval of new agents to motivate investment in early phase development; and (vi) collecting data needed for health technology assessment continuously throughout the drug development process (before and after approval) to minimize delays in patient access. Collaboration across industry, academia, regulators, and payers will be necessary to enact change and to unlock the existing potential for cardiovascular clinical drug development. CONCLUSIONS: A coordinated effort involving academia, regulators, industry, and payors will help to foster better and more effective conduct of clinical cardiovascular trials, supporting earlier availability of innovative therapies and better management of cardiovascular diseases.

Clinical trials in hospitalized heart failure patients: targeting interventions to optimal phenotypic subpopulations.

With one possible exception, the last decade of clinical trials in hospitalized heart failure (HHF) patients has failed to demonstrate improvement in long-term clinical outcomes. This trend necessitates a need to evaluate optimal drug development strategies and standards of trial conduct. It has become increasingly important to recognize the heterogeneity among HHF patients and the differential characterization of novel drug candidates. Targeting these agents to specific subpopulations may afford optimal net response related to the particular mode of action of the drug. Analyses of previous trials demonstrate profound differences in the baseline characteristics of patients enrolled across global regions and participating sites. Such differences may influence risks for events and interpretation of results. Therefore, the actual execution of trials and the epidemiology of HHF populations at the investigative sites must be taken into consideration. Collaboration among participating sites including the provision of registry data tailored to the planned development program will optimize trial conduct. Observational data prior to study initiation may enable sites to feedback and engage in protocol development to allow for feasible and valid clinical trial conduct. This site-centered, epidemiology-based network environment may facilitate studies in specific patient populations and promote optimal data collection and clear interpretation of drug safety and efficacy. This review summarizes the roundtable discussion held by a multidisciplinary team of representatives from academia, National Institutes of Health, industry, regulatory agencies, payers, and contract and academic research organizations to answer the question: Who should be targeted for novel therapies in HHF?

Site selection in global clinical trials in patients hospitalized for heart failure: perceived problems and potential solutions.

There are over 1 million hospitalizations for heart failure (HF) annually in the United States alone, and a similar number has been reported in Europe. Recent clinical trials investigating novel therapies in patients with hospitalized HF (HHF) have been negative, and the post-discharge event rate remains unacceptably high. The lack of success with HHF trials stem from problems with understanding the study drug, matching the drug to the appropriate HF subgroup, and study execution. Related to the concept of study execution is the importance of including appropriate study sites in HHF trials. Often overlooked issues include consideration of the geographic region and the number of patients enrolled at each study center. Marked differences in baseline patient co-morbidities, serum biomarkers, treatment utilization and outcomes have been demonstrated across geographic regions. Furthermore, patients from sites with low recruitment may have worse outcomes compared to sites with higher enrollment patterns. Consequently, sites with poor trial enrollment may influence key patient end points and likely do not justify the costs of site training and maintenance. Accordingly, there is an unmet need to develop strategies to identify the right study sites that have acceptable patient quantity and quality. Potential approaches include, but are not limited to, establishing a pre-trial registry, developing site performance metrics, identifying a local regionally involved leader and bolstering recruitment incentives. This manuscript summarizes the roundtable discussion hosted by the Food and Drug Administration between members of academia, the National Institutes of Health, industry partners, contract research organizations and academic research organizations on the importance of selecting optimal sites for successful trials in HHF.

Clinical outcome endpoints in heart failure trials: a European Society of Cardiology Heart Failure Association consensus document.

Endpoint selection is a critically important step in clinical trial design. It poses major challenges for investigators, regulators, and study sponsors, and it also has important clinical and practical implications for physicians and patients. Clinical outcomes of interest in heart failure trials include all-cause mortality, cause-specific mortality, relevant non-fatal morbidity (e.g., all-cause and cause-specific hospitalization), composites capturing both morbidity and mortality, safety, symptoms, functional capacity, and patient-reported outcomes. Each of these endpoints has strengths and weaknesses that create controversies regarding which is most appropriate in terms of clinical importance, sensitivity, reliability, and consistency. Not surprisingly, a lack of consensus exists within the scientific community regarding the optimal endpoint(s) for both acute and chronic heart failure trials. In an effort to address these issues, the Heart Failure Association of the European Society of Cardiology (HFA-ESC) convened a group of expert heart failure clinical investigators, biostatisticians, regulators, and pharmaceutical industry scientists (Nice, France, 12-13 February 2012) to evaluate the challenges of defining heart failure endpoints in clinical trials and to develop a consensus framework. This report summarizes the group's recommendations for achieving common views on heart failure endpoints in clinical trials.

Interaction between baseline and early worsening of renal function and efficacy of renin-angiotensin-aldosterone system blockade in patients with heart failure: insights from the Val-HeFT study.

AIMS: We evaluated the effect of (dual) renin-angiotensin-aldosterone system (RAAS) blockade with valsartan and an ACE inhibitor [92.7% of patients were treated with an ACE inhibitor in the Valsartan in Heart Failure Trial (Val-HeFT)] in patients with NYHA class II-IV heart failure (HF) and reduced EF on cardiovascular (CV) death and HF hospitalization by subgroups and by presence of early worsening of renal function (EWRF) and according to baseline estimated glomerular filtration rate (eGFR). METHODS AND RESULTS: We analysed the data from 5010 patients enrolled in the Val-HeFT study. A total of 2346 (46.8%) patients had baseline renal impairment (i.e. baseline eGFR <60 mL/min/1.73 m(2)). Further, 425 patients (8.6%) had EWRF (i.e. eGFR decrease >20% within 1 month after randomization), whereas 4503 patients (91.4%) had ≤20% decline in eGFR. Overall, the difference between valsartan and placebo on the composite endpoint of CV death and HF hospitalization was significant [P = 0.0005; hazard ratio (HR) 0.83, 95% confidence interval (CI) 0.75-0.92)]. In patients with baseline renal impairment, the difference between the treatment groups was also significant (P = 0.0002; HR 0.76, 95% CI 0.66-0.88). Patients with EWRF had higher risk of CV death and HF hospitalization vs. those without ERWF (P < 0.0001; HR 1.44, 95% CI 1.21-1.71), and within the EWRF group a significant difference was also observed between valsartan and placebo (P = 0.0086; HR 0.63, 95% CI 0.45-0.89). However, the interaction between treatment and eGFR at Month 1 was not significant (P = 0.1160). CONCLUSION: Benefits were maintained in patients with renal dysfunction at baseline and those who experienced EWRF.

Standardization of outcome measures in clinical trials of pharmacological treatment for abdominal aortic aneurysm.

An abdominal aortic aneurysm (AAA) is a common aortic wall disease with an increased prevalence in the elderly population (4-8% for those aged >65 years). Many AAAs are slow growing and remain insidious. Current standard of care for patients with small AAAs (<49 mm) is surveillance, with interventional therapy (open surgical repair or endovascular aneurysm repair) recommended for large (>50-55 mm), rapidly growing (>10 mm/year) or symptomatic AAAs. Although open surgical repair or endovascular aneurysm repair are effective, significant short- and long-term postoperative morbidity and mortality occurs. Currently, there is no pharmacological treatment specific for AAA; the need for the development of targeted pharmacological therapies based on clinically relevant and feasible outcomes acceptable to the medical community, regulatory agencies and third-party payers is high. A consensus on such end points will be critical to accelerating the development of pharmacological agents to prevent formation, arrest the expansion and reduce the rupture risk of AAA.

Interleukin-1ß inhibition and the prevention of recurrent cardiovascular events: rationale and design of the Canakinumab Anti-inflammatory Thrombosis Outcomes Study (CANTOS).

BACKGROUND: Inflammation contributes to all phases of the atherothrombotic process, and patients with elevated inflammatory biomarkers such as high-sensitivity C-reactive protein (hsCRP) have increased vascular risk. Yet, it remains unknown whether direct inhibition of inflammation will reduce cardiovascular event rates. DESIGN: The CANTOS will evaluate whether interleukin-1ß (IL-1ß) inhibition as compared with placebo can reduce rates of recurrent myocardial infarction, stroke, and cardiovascular death among stable patients with coronary artery disease who remain at high vascular risk due to persistent elevations of hsCRP (>2 mg/L) despite contemporary secondary prevention strategies. Canakinumab is a human monoclonal antibody that selectively neutralizes IL-1ß, a proinflammatory cytokine that plays multiple roles in the atherothrombotic process and that undergoes activation by the nucleotide-binding leucine-rich repeat-containing pyrin receptor 3 inflammasome, a process promoted by cholesterol crystals. Canakinumab significantly reduces systemic C-reactive protein and other inflammatory biomarker levels, is generally well tolerated, and is currently indicated for the treatment of inherited IL-1ß driven inflammatory diseases such as the Muckle-Wells syndrome. In a multinational collaborative effort using an event-driven intention-to-treat protocol, CANTOS will randomly allocate 17,200 stable postmyocardial infarction patients with persistent elevation of hsCRP to either placebo or to canakinumab at doses of 50, 150, or 300 mg every 3 months, administered subcutaneously. All participants will be followed up over an estimated period of up to 4 years for the trial primary end point (nonfatal myocardial infarction, nonfatal stroke, cardiovascular death) as well as for other vascular events, total mortality, adverse events, and specific clinical end points associated with inflammation including new onset diabetes, venous thrombosis, and atrial fibrillation. SUMMARY: If positive, CANTOS would confirm the inflammatory hypothesis of atherothrombosis and provide a novel cytokine-based therapy for the secondary prevention of cardiovascular disease and new-onset diabetes.

Peripheral artery disease, biomarkers, and darapladib.

OBJECTIVE: Subjects with peripheral artery disease (PAD) are at increased risk of cardiovascular morbidity and mortality, perhaps in part, related to increased levels of inflammation, platelet activity, and lipids. We therefore sought to investigate the relationship between PAD and levels of inflammatory, platelet, and lipid biomarkers and the treatment effect of darapladib, a novel lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) inhibitor. METHODS: This is a post hoc analysis of the 959 patients with coronary disease or their risk equivalent receiving atorvastatin who were randomized to receive darapladib or placebo to examine the effects of an Lp-PLA(2) inhibitor on the biomarkers of cardiovascular risk. We conducted an exploratory analysis evaluating the levels of biomarkers in subjects with PAD (n = 172) compared with those without PAD (n = 787). RESULTS: After adjustment for age, sex, smoking, body mass index, and diabetes, subjects with PAD had greater levels of matrix metalloproteinase-9 (between group comparisons 22%, 95% confidence interval [10-31], P < .01), myeloperoxidase (12% [2-20], P = .01), interleukin-6 (13% [4-21], P = .01), adiponectin (17% [7-26], P < .01), intercellular adhesion molecule-1 (7% [2-11], P < .01), osteoprotegrin (6% [1-10], P = .02), CD40 ligand (15% [1-28], P = .04), high-sensitivity C-reactive protein (17% [1-31], P = .04), and triglycerides (11% [0.2-21], P = .05). No significant difference was detected for Lp-PLA(2) activity, P-selectin, urinary 11-dehydrothroboxane B2, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol between subjects with and without PAD. Darapladib produced highly significant inhibition of Lp-PLA(2) activity when compared with placebo at weeks 4 and 12 (P < .01) in patients with and without PAD. CONCLUSIONS: Subjects with PAD had elevated levels of matrix metalloproteinase-9, myeloperoxidase, interleukin-6, adiponectin, intercellular adhesion molecule-1, osteoprotegrin, CD40 ligand, high-sensitivity C-reactive protein, and triglycerides compared with those without PAD. Darapladib, a novel Lp-PLA(2) inhibitor, was equally effective in reducing Lp-PLA(2) activity levels in subjects with and without PAD.

Differential protein biomarker expression and their time-course in patients with a spectrum of stable and unstable coronary syndromes in the Integrated Biomarker and Imaging Study-1 (IBIS-1).

OBJECTIVES: IBIS-1 was a pilot study undertaken to correlate coronary imaging with circulating biomarker expression in patients with stable angina, unstable angina and acute myocardial infarction. We hypothesized that patients at high risk of future events could be identified in the future by a combination of high risk plaque features by plaque echogenicity and palpography and a set of circulating blood biomarkers. RESULTS AND METHODS: We assessed the expression of conventional biomarkers and novel marker protein microarray (170 analytes) over 6 months. There were no strong correlations observed between conventional biomarkers and coronary imaging in non-culprit artery. Proteomic microarray was performed in 66 patients. Seventy eight (45%) analytes showed dynamic changes over time. Using hierarchical clustering and principal component analysis two subsets of biomarkers were identified: initial up-regulation and decrease over time (D-dimer, hepatocyte growth factor, CXCL9/MIG, platelet factor 4/CXCL4, CTACK, C-6 Kine, follistatin, and FGF-7) and the opposite increase (PAI-1- anti-apoptotic protein and I-309--chemokine induced on the human endothelium by Lp(a)). CONCLUSIONS: Proteomic analysis identifies dynamic patterns in circulating biomarkers in a wide range of patients with coronary artery disease. Further large natural history studies are needed to better define multibiomarker sets for identification of patients at risk of future CV events.

The ATHEROMA (Atorvastatin Therapy: Effects on Reduction of Macrophage Activity) Study. Evaluation using ultrasmall superparamagnetic iron oxide-enhanced magnetic resonance imaging in carotid disease.

OBJECTIVES: The aim of this study was to evaluate the effects of low-dose (10 mg) and high-dose (80 mg) atorvastatin on carotid plaque inflammation as determined by ultrasmall superparamagnetic iron oxide (USPIO)-enhanced carotid magnetic resonance imaging (MRI). The hypothesis was that treatment with 80 mg atorvastatin would demonstrate quantifiable changes in USPIO-enhanced MRI-defined inflammation within the first 3 months of therapy. BACKGROUND: Preliminary studies indicate that USPIO-enhanced MRI can identify macrophage infiltration in human carotid atheroma in vivo and hence may be a surrogate marker of plaque inflammation. METHODS: Forty-seven patients with carotid stenosis >40% on duplex ultrasonography and who demonstrated intraplaque accumulation of USPIO on MRI at baseline were randomly assigned in a balanced, double-blind manner to either 10 or 80 mg atorvastatin daily for 12 weeks. Baseline statin therapy was equivalent to 10 mg of atorvastatin or less. The primary end point was change from baseline in signal intensity (DeltaSI) on USPIO-enhanced MRI in carotid plaque at 6 and 12 weeks. RESULTS: Twenty patients completed 12 weeks of treatment in each group. A significant reduction from baseline in USPIO-defined inflammation was observed in the 80-mg group at both 6 weeks (DeltaSI 0.13; p = 0.0003) and at 12 weeks (DeltaSI 0.20; p < 0.0001). No difference was observed with the low-dose regimen. The 80-mg atorvastatin dose significantly reduced total cholesterol by 15% (p = 0.0003) and low-density lipoprotein cholesterol by 29% (p = 0.0001) at 12 weeks. CONCLUSIONS: Aggressive lipid-lowering therapy over a 3-month period is associated with significant reduction in USPIO-defined inflammation. USPIO-enhanced MRI methodology may be a useful imaging biomarker for the screening and assessment of therapeutic response to "anti-inflammatory" interventions in patients with atherosclerotic lesions. (Effects of Atorvastatin on Macrophage Activity and Plaque Inflammation Using Magnetic Resonance Imaging [ATHEROMA]; NCT00368589).

Assessment on the Prevention of Progression by Rosiglitazone on Atherosclerosis in diabetes patients with Cardiovascular History (APPROACH): study design and baseline characteristics.

BACKGROUND: Rosiglitazone, a thiazolidinedione, has effects on insulin sensitivity and cardiovascular risk factors that may favorably impact the progression of coronary atherosclerosis. METHODS: APPROACH is a double-blind randomized clinical trial comparing the effects of the insulin sensitizer rosiglitazone with the insulin secretagogue glipizide on the progression of coronary atherosclerosis. Patients with type 2 diabetes and coronary artery disease undergoing clinically indicated coronary angiography or percutaneous coronary intervention are randomized to receive rosiglitazone or glipizide for 18 months using a titration algorithm designed to provide comparable glycemic control between treatment groups. The primary end point is change in percent atheroma volume from baseline to study completion in a nonintervened coronary artery, as measured by intravascular ultrasound. Cardiovascular events are adjudicated by an end point committee. RESULTS: A total of 672 patients were randomized. The mean age was 61 years, hemoglobin A(1c) (HbA(1c)) 7.2%, body mass index 29.5 kg/m(2), and median duration of diabetes 4.8 years. At baseline, approximately half of the participants were receiving oral antidiabetic monotherapy (53.9%) with 27.5% receiving dual combination therapy and 17.9% treated with diet and exercise alone. Approximately two thirds of the participants (68%) had dyslipidemia, 79.9% hypertension, and 24% prior myocardial infarction. CONCLUSIONS: APPROACH has fully enrolled a high-risk patient population and will compare the glucose-independent effects of rosiglitazone and glipizide on the progression of coronary atherosclerosis, as well as provide additional data on the cardiovascular safety of rosiglitazone in patients with type 2 diabetes and coronary artery disease.

Effects of the direct lipoprotein-associated phospholipase A(2) inhibitor darapladib on human coronary atherosclerotic plaque.

BACKGROUND: Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) is expressed abundantly in the necrotic core of coronary lesions, and products of its enzymatic activity may contribute to inflammation and cell death, rendering plaque vulnerable to rupture. METHODS AND RESULTS: This study compared the effects of 12 months of treatment with darapladib (an oral Lp-PLA(2) inhibitor, 160 mg daily) or placebo on coronary atheroma deformability (intravascular ultrasound palpography) and plasma high-sensitivity C-reactive protein in 330 patients with angiographically documented coronary disease. Secondary end points included changes in necrotic core size (intravascular ultrasound radiofrequency), atheroma size (intravascular ultrasound gray scale), and blood biomarkers. BACKGROUND: =0.37). In contrast, Lp-PLA(2) activity was inhibited by 59% with darapladib (P<0.001 versus placebo). After 12 months, there were no significant differences between groups in plaque deformability (P=0.22) or plasma high-sensitivity C-reactive protein (P=0.35). In the placebo-treated group, however, necrotic core volume increased significantly (4.5+/-17.9 mm(3); P=0.009), whereas darapladib halted this increase (-0.5+/-13.9 mm(3); P=0.71), resulting in a significant treatment difference of -5.2 mm(3) (P=0.012). These intraplaque compositional changes occurred without a significant treatment difference in total atheroma volume (P=0.95). CONCLUSIONS: Despite adherence to a high level of standard-of-care treatment, the necrotic core continued to expand among patients receiving placebo. In contrast, Lp-PLA(2) inhibition with darapladib prevented necrotic core expansion, a key determinant of plaque vulnerability. These findings suggest that Lp-PLA(2) inhibition may represent a novel therapeutic approach.

Inhibition of lipoprotein-associated phospholipase A2 reduces complex coronary atherosclerotic plaque development.

Increased lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) activity is associated with increased risk of cardiac events, but it is not known whether Lp-PLA(2) is a causative agent. Here we show that selective inhibition of Lp-PLA(2) with darapladib reduced development of advanced coronary atherosclerosis in diabetic and hypercholesterolemic swine. Darapladib markedly inhibited plasma and lesion Lp-PLA(2) activity and reduced lesion lysophosphatidylcholine content. Analysis of coronary gene expression showed that darapladib exerted a general anti-inflammatory action, substantially reducing the expression of 24 genes associated with macrophage and T lymphocyte functioning. Darapladib treatment resulted in a considerable decrease in plaque area and, notably, a markedly reduced necrotic core area and reduced medial destruction, resulting in fewer lesions with an unstable phenotype. These data show that selective inhibition of Lp-PLA(2) inhibits progression to advanced coronary atherosclerotic lesions and confirms a crucial role of vascular inflammation independent from hypercholesterolemia in the development of lesions implicated in the pathogenesis of myocardial infarction and stroke.

The effect of darapladib on plasma lipoprotein-associated phospholipase A2 activity and cardiovascular biomarkers in patients with stable coronary heart disease or coronary heart disease risk equivalent: the results of a multicenter, randomized, double-blind, placebo-controlled study.

OBJECTIVES: This study examined the effects of darapladib, a selective lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) inhibitor, on biomarkers of cardiovascular (CV) risk. BACKGROUND: Elevated Lp-PLA(2) levels are associated with an increased risk of CV events. METHODS: Coronary heart disease (CHD) and CHD-risk equivalent patients (n = 959) receiving atorvastatin (20 or 80 mg) were randomized to oral darapladib 40 mg, 80 mg, 160 mg, or placebo once daily for 12 weeks. Blood samples were analyzed for Lp-PLA(2) activity and other biomarkers. RESULTS: Baseline low-density lipoprotein cholesterol (LDL-C) was 67 +/- 22 mg/dl. Plasma Lp-PLA(2) was higher in older patients (>or=75 years), in men, in those taking atorvastatin 20 mg, at LDL-C >or=70 mg/dl or high-density lipoprotein cholesterol (HDL-C) <40 mg/dl, or in those with documented vascular disease (multivariate regression; p < 0.01). Darapladib 40, 80, and 160 mg inhibited Lp-PLA(2) activity by approximately 43%, 55%, and 66% compared with placebo (p < 0.001 weeks 4 and 12). Sustained dose-dependent inhibition was noted overall in both atorvastatin groups and at different baseline LDL-C (>or=70 vs. <70 mg/dl) and HDL-C (<40 vs. >or=40 mg/dl). At 12 weeks, darapladib 160 mg decreased interleukin (IL)-6 by 12.3% (95% confidence interval [CI] -22% to -1%; p = 0.028) and high-sensitivity C-reactive protein (hs-CRP) by 13.0% (95% CI -28% to +5%; p = 0.15) compared with placebo. The Lp-PLA(2) inhibition produced no detrimental effects on platelet biomarkers (P-selectin, CD40 ligand, urinary 11-dehydrothromboxane B(2)). No major safety concerns were noted. CONCLUSIONS: Darapladib produced sustained inhibition of plasma Lp-PLA(2) activity in patients receiving intensive atorvastatin therapy. Changes in IL-6 and hs-CRP after 12 weeks of darapladib 160 mg suggest a possible reduction in inflammatory burden. Further studies will determine whether Lp-PLA(2) inhibition is associated with favorable effects on CV events.

Site-specific atherogenic gene expression correlates with subsequent variable lesion development in coronary and peripheral vasculature.

OBJECTIVE: The relationship between specific gene regulation and subsequent development and progression of atherosclerosis is incompletely understood. We hypothesized that genes in the vasculature related to cholesterol metabolism, inflammation, and insulin signaling pathways are differentially regulated in a site-specific and time-dependent manner. METHODS AND RESULTS: Expression of 59 genes obtained from coronary, carotid, and thoracic aortic arteries were characterized from diabetic (DM)/hypercholesterolemic (HC) swine (n=52) 1, 3, and 6 months after induction. Lesion development in the 3 arterial beds was quantified and characterized at 1, 3, 6, and 9 months. Progressive lesion development was observed in the coronary>thoracic aorta>>carotid arteries. Genes involved in cholesterol metabolism and insulin pathways were upregulated in coronaries>thoracic aortae>carotids. Inflammatory genes were more markedly upregulated in coronary arteries than the other 2 arteries. Genes implicated in plaque instability (eg, matrix metalloproteinase-9, CCL2 and Lp-PLA(2) mRNAs) were only upregulated at 6 months in coronary arteries. CONCLUSIONS: Variable gene expression, both in regard to the arterial bed and duration of disease, was associated with variable plaque development and progression. These findings may provide further insight into the atherosclerotic process and development of potential therapeutic targets.

Role of lipoprotein-associated phospholipase A2 in leukocyte activation and inflammatory responses.

BACKGROUND: Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an emerging cardiovascular risk marker. To explore the biologic role of Lp-PLA2 in atherosclerosis, we examined its expression and contribution to leukocyte activation under proatherogenic conditions. METHODS AND RESULTS: Following the induction of diabetes and hypercholesterolemia in a porcine model, a rapid increase in plasma Lp-PLA2 activity was observed at 1 month. This was accompanied by upregulated Lp-PLA2 mRNA expression by peripheral blood mononuclear cells (PBMC) at 3 months, and elevated Lp-PLA2 mRNA expression in coronary arteries at 6 months. These changes were paralleled by increased inflammatory responses by circulating PBMC (ICAM-1, IL-6), in coronary tissues (ICAM-1, VCAM-1), and the subsequent accumulation of inflammatory cells. In human PBMC, proinflammatory mediators augmented the synthesis and release of functional Lp-PLA2. Furthermore, lysophosphatidylcholine (lysoPC), a product of Lp-PLA2 activity, induced an increase in several inflammatory cytokines (IL-1beta, IL-6, TNF-alpha) in a concentration-dependent manner. In contrast, Lp-PLA2 inhibition (SB677116; 1 microM) abrogated the inflammatory response elicited by oxidized LDL. CONCLUSIONS: In an experimental model of diabetes and hypercholesterolemia, leukocyte activation was associated with augmented Lp-PLA2 expression. In vitro, Lp-PLA2 activity mediated leukocyte activation and inflammatory responses, whereas Lp-PLA2 inhibition abolished inflammatory responses induced by oxidized LDL. Collectively, these observations support a proatherogenic role for Lp-PLA2.

Lp-PLA2: a new kid on the block.

BACKGROUND: Atherosclerosis is a systemic disease with focal rupture of vulnerable plaque responsible for major clinical events. Several population-based studies indicate an association between lipoprotein-associated phospholipase A2 (Lp-PLA2) and cardiovascular events. Lp-PLA2 is emerging as a biomarker that may be a potential link between oxidized LDL cholesterol and multifocal plaque vulnerability. CONTENT: Lp-PLA2 is produced by inflammatory cells of myeloid origin, is associated with circulating atherogenic lipoproteins (e.g., LDL), and is highly expressed in vulnerable plaques (de novo expression). Specificity of Lp-PLA2 toward polar phospholipids in oxidized LDL may contribute to the formation of downstream products (e.g., lysophosphatidylcholine and nonesterified fatty acids) that mediate processes intimately involved in plaque vulnerability in situ, including proinflammatory cell phenotype and macrophage death. Recent studies in patients with acute coronary syndrome (ACS) demonstrate that Lp-PLA2 and LDL measurements are not useful to assess the long-term cardiovascular risk shortly after the acute event, most likely because of the acute drop in LDL values that is commonly observed in ACS. However, when measured at later time points, Lp-PLA2 emerges as an independent predictor of the long-term cardiovascular risk, according to multivariate analysis. SUMMARY: Lp-PLA2 is an intriguing marker of cardiovascular risk and may also be a marker of plaque activity/vulnerability. Despite these findings, unanswered questions still exist with respect to this enzyme and its biologic role in atherosclerosis. Addressing these questions will help clarify the clinical utility of measuring Lp-PLA2 in routine clinical practice in the context of other approaches for identifying high-risk patients.