Michele Mercuri

Edoxaban versus Warfarin in Patients with Atrial Fibrillation

BACKGROUND Edoxaban is a direct oral factor Xa inhibitor with proven antithrombotic effects. The long-term efficacy and safety of edoxaban as compared with warfarin in patients with atrial fibrillation is not known. METHODS We conducted a randomized, double-blind, double-dummy trial comparing two once-daily regimens of edoxaban with warfarin in 21,105 patients with moderate-to-high-risk atrial fibrillation (median follow-up, 2.8 years). The primary efficacy end point was stroke or systemic embolism. Each edoxaban regimen was tested for noninferiority to warfarin during the treatment period. The principal safety end point was major bleeding. RESULTS The annualized rate of the primary end point during treatment was 1.50% with warfarin (median time in the therapeutic range, 68.4%), as compared with 1.18% with high-dose edoxaban (hazard ratio, 0.79; 97.5% confidence interval [CI], 0.63 to 0.99; P<0.001 for noninferiority) and 1.61% with low-dose edoxaban (hazard ratio, 1.07; 97.5% CI, 0.87 to 1.31; P=0.005 for noninferiority). In the intention-to-treat analysis, there was a trend favoring high-dose edoxaban versus warfarin (hazard ratio, 0.87; 97.5% CI, 0.73 to 1.04; P=0.08) and an unfavorable trend with low-dose edoxaban versus warfarin (hazard ratio, 1.13; 97.5% CI, 0.96 to 1.34; P=0.10). The annualized rate of major bleeding was 3.43% with warfarin versus 2.75% with high-dose edoxaban (hazard ratio, 0.80; 95% CI, 0.71 to 0.91; P<0.001) and 1.61% with low-dose edoxaban (hazard ratio, 0.47; 95% CI, 0.41 to 0.55; P<0.001). The corresponding annualized rates of death from cardiovascular causes were 3.17% versus 2.74% (hazard ratio, 0.86; 95% CI, 0.77 to 0.97; P=0.01), and 2.71% (hazard ratio, 0.85; 95% CI, 0.76 to 0.96; P=0.008), and the corresponding rates of the key secondary end point (a composite of stroke, systemic embolism, or death from cardiovascular causes) were 4.43% versus 3.85% (hazard ratio, 0.87; 95% CI, 0.78 to 0.96; P=0.005), and 4.23% (hazard ratio, 0.95; 95% CI, 0.86 to 1.05; P=0.32). CONCLUSIONS Both once-daily regimens of edoxaban were noninferior to warfarin with respect to the prevention of stroke or systemic embolism and were associated with significantly lower rates of bleeding and death from cardiovascular causes. (Funded by Daiichi Sankyo Pharma Development; ENGAGE AF-TIMI 48 ClinicalTrials.gov number, NCT00781391.).

Lipid Lowering by Simvastatin Induces Regression of Human Atherosclerotic Lesions Two Years’ Follow-Up by High-Resolution Noninvasive Magnetic Resonance Imaging

Background—Statins are widely used to treat hypercholesterolemia and atherosclerotic disease. Noninvasive MRI allows serial monitoring of atherosclerotic plaque size changes. Our aim was to investigate the effects of lipid lowering with simvastatin on atherosclerotic lesions. Methods and Results—A total of 44 aortic and 32 carotid artery plaques were detected in 21 asymptomatic hypercholesterolemic patients at baseline. The effects of statin on these atherosclerotic lesions were evaluated as changes versus baseline in lumen area (LA), vessel wall thickness (VWT), and vessel wall area (VWA) by MRI. Maximal reduction of plasma total and LDL cholesterol by simvastatin (23% and 38% respectively;P <0.01 versus baseline) was achieved after ≈6 weeks of therapy and maintained thereafter throughout the study. Significant (P <0.01) reductions in maximal VWT and VWA at 12 months (10% and 11% for aortic and 8% and 11% for carotid plaques, respectively), without changes in LA, have been reported. Further decreases in VWT and VWA ranging from 12% to 20% were observed at 18 and 24 months. A slight but significant increase (ranging from 4% to 6%) in LA was seen in both carotid and aortic lesions at these later time points. Conclusion—The present study demonstrates that maintained lipid-lowering therapy with simvastatin is associated with significant regression of established atherosclerotic lesions in humans. Our observations indicate that lipid-lowering therapy is associated with sustained vascular remodeling and emphasize the need for longer-term treatment.

Effects of Lipid-Lowering by Simvastatin on Human Atherosclerotic Lesions A Longitudinal Study by High-Resolution, Noninvasive Magnetic Resonance Imaging

Background—This study was designed to investigate the effects of lipid-lowering by simvastatin on human atherosclerotic lesions. Methods and Results—Eighteen asymptomatic hypercholesterolemic patients with documented aortic and/or carotid atherosclerotic plaques were selected for the study. A total of 35 aortic and 25 carotid artery plaques were detected. Serial black-blood MRI of the aorta and carotid artery of the patients was performed at baseline and 6 and 12 months after lipid-lowering therapy with simvastatin. The effects of the treatment on atherosclerotic lesions were measured as changes in lumen area, vessel wall thickness, and vessel wall area, a surrogate of atherosclerotic burden. Simvastatin induced a significant (P <0.01) reduction in total and LDL cholesterol levels at 6 weeks that was maintained thereafter. At 6 months, no changes in lumen area, vessel wall thickness, or vessel wall area were observed. However, at 12 months, significant reductions in vessel wall thickness and vessel wall area, without changes in lumen area, were observed in both aortic and carotid arteries (P <0.001). Conclusions—This in vivo human study demonstrates that effective and maintained lipid-lowering therapy by simvastatin is associated with a significant regression of atherosclerotic lesions. Our observation suggests that statins induce vascular remodeling, as manifested by reduced atherosclerotic burden without changes in the lumen.

Evaluation of the novel factor Xa inhibitor edoxaban compared with warfarin in patients with atrial fibrillation: Design and rationale for the Effective aNticoaGulation with factor xA next GEneration in Atrial Fibrillation–Thrombolysis In Myocardial Infarction study 48 (ENGAGE AF–TIMI 48)

BACKGROUND Vitamin K antagonists have been the standard oral antithrombotic used for more than a half century for prevention and treatment of thromboembolism. Their limitations include multiple food and drug interactions and need for frequent monitoring and dose adjustments. Edoxaban is a selective and direct factor Xa inhibitor that may provide effective, safe, and more convenient anticoagulation. STUDY DESIGN ENGAGE AF-TIMI 48 is a phase 3, randomized, double-blind, double-dummy, multinational, noninferiority design megatrial comparing 2 exposure strategies of edoxaban to warfarin. Approximately 20,500 subjects will be randomized to edoxaban high exposure (60 mg daily, adjusted for drug clearance), edoxaban low exposure (30 mg daily, adjusted for drug clearance), or warfarin titrated to an international normalized ratio of 2.0 to 3.0. The edoxaban strategies provide for dynamic dose reductions in subjects with anticipated increased drug exposure. Blinded treatment is maintained through the use of sham international normalized ratios in patients receiving edoxaban. Eligibility criteria include electrical documentation of atrial fibrillation ≤12 months and a CHADS(2) score ≥2. Randomization is stratified by CHADS(2) score and anticipated drug exposure. The primary objective is to determine whether edoxaban is noninferior to warfarin for the prevention of stroke and systemic embolism. The primary safety end point is modified International Society on Thrombosis and Haemostasis major bleeding. Recruitment began in November 2008. The expected median follow-up is 24 months. CONCLUSIONS ENGAGE AF-TIMI 48 is a phase 3 comparison of the novel oral factor Xa inhibitor edoxaban to warfarin for the prevention of thromboembolism in patients with atrial fibrillation.

Pravastatin reduces carotid intima-media thickness progression in an asymptomatic hypercholesterolemic Mediterranean population: The Carotid Atherosclerosis Italian Ultrasound Study

PURPOSE The Carotid Atherosclerosis Italian Ultrasound Study (CAIUS) was performed to test the effects of lipid lowering on the progression of carotid intima-media thickness (IMT) in 305 asymptomatic patients from a Mediterranean country. PATIENTS AND METHODS Eligibility included hypercholesterolemia (baseline means: low-density lipoprotein [LDL] = 4.68 mmol/L, high-density lipoprotein [HDL] = 1.37 mmol/L), and at least one 1.3 < IMT < 3.5 mm in the carotid arteries. Patients (mean age 55 years, 53% male) were assigned to pravastatin (40 mg/day, n = 151) or placebo (n not equal to 154). Ultrasound imaging was used to quantify IMT at baseline, and semiannually thereafter for up to 3 years. The mean of the 12 maximum IMTs (MMaxIMT), was calculated for each patient visit, and used to determine each patients longitudinal progression slope. The intention-to-treat group difference in the MMaxIMT progression was chosen a priori as the primary end point. RESULTS Five serious cardiovascular events (1 fatal myocardial infarction), and 7 drop-outs for cancer were registered. In the pravastatin group, LDL decreased -0.22 after 3 months versus -0.01 in the placebo group, and remained substantially unchanged afterward (-0.23 versus +0.01 at 36 months, respectively). Progression of the MMaxIMT was 0.009 +/- 0.0027 versus -0.0043 +/- 0.0028 mm/year (mean +/- SE, P < 0.0007) in the placebo and pravastatin groups, respectively. IMT progression slopes diverged after 6 months of treatment. CONCLUSIONS Pravastatin stops the progression of carotid IMT in asymptomatic, moderately hypercholesterolemic men and women. This finding extends the beneficial effects of cholesterol lowering to the primary prevention of atherosclerosis in a population with relatively low cardiovascular event rates, and suggests that this benefit is mediated by specific morphological effects on early stages of plaque development.

Efficacy and Safety of Statin Therapy in Children With Familial Hypercholesterolemia A Randomized, Double-Blind, Placebo-Controlled Trial With Simvastatin

Background—A multicenter, randomized, double-blind, placebo-controlled study was conducted to evaluate LDL cholesterol–lowering efficacy, overall safety, and tolerability and the influence on growth and pubertal development of simvastatin in a large cohort of boys and girls with heterozygous familial hypercholesterolemia (heFH). Methods and Results—A total of 173 heFH children (98 boys and 75 girls) were included in this study. After a 4-week diet/placebo run-in period, children with heFH were randomized to either simvastatin or placebo in a ratio of 3:2. Simvastatin was started at 10 mg/d and titrated at 8-week intervals to 20 and then 40 mg/d. During a 24-week extension period, the patients continued to receive simvastatin (40 mg) or placebo according to their assignment. After 48 weeks of simvastatin therapy, there were significant reductions of LDL cholesterol (−41%), total cholesterol (−31%), apolipoprotein B (−34%), VLDL cholesterol (−21%), and triglyceride (−9%) levels. HDL cholesterol and apolipoprotein A-I levels were increased by 3.3% and 10.4%, respectively (not significant). No safety issues became evident. Except for small decreases in dehydroepiandrosterone sulfate compared with placebo, there were no significant changes from baseline in adrenal, gonadal, and pituitary hormones in either treatment group. Conclusions—Simvastatin significantly reduced LDL cholesterol, total cholesterol, triglyceride, VLDL cholesterol, and apolipoprotein B levels and was well tolerated in children with heFH. There was no evidence of any adverse effect of simvastatin on growth and pubertal development. Therefore, simvastatin at doses up to 40 mg is a well-tolerated and effective therapy for heFH children.

Association between edoxaban dose, concentration, anti-Factor Xa activity, and outcomes: an analysis of data from the randomised, double-blind ENGAGE AF-TIMI 48 trial.

BACKGROUND New oral anticoagulants for stroke prevention in atrial fibrillation were developed to be given in fixed doses without the need for the routine monitoring that has hindered usage and acceptance of vitamin K antagonists. A concern has emerged, however, that measurement of drug concentration or anticoagulant activity might be needed to prevent excess drug concentrations, which significantly increase bleeding risk. In the ENGAGE AF-TIMI 48 trial, higher-dose and lower-dose edoxaban were compared with warfarin in patients with atrial fibrillation. Each regimen incorporated a 50% dose reduction in patients with clinical features known to increase edoxaban drug exposure. We aim to assess whether adjustment of edoxaban dose in this trial prevented excess drug concentration and the risk of bleeding events. METHODS We analysed data from the randomised, double-blind ENGAGE AF-TIMI 48 trial. We correlated edoxaban dose, plasma concentration, and anti-Factor Xa (FXa) activity and compared efficacy and safety outcomes with warfarin stratified by dose reduction status. Patients with atrial fibrillation and at moderate to high risk of stroke were randomly assigned in a 1:1:1 ratio to receive warfarin, dose adjusted to an international normalised ratio of 2·0-3·0, higher-dose edoxaban (60 mg once daily), or lower-dose edoxaban (30 mg once daily). Randomisation was done with use of a central, 24 h, interactive, computerised response system. International normalised ratio was measured using an encrypted point-of-care device. To maintain masking, sham international normalised ratio values were generated for patients assigned to edoxaban. Edoxaban (or placebo-edoxaban in warfarin group) doses were halved at randomisation or during the trial if patients had creatinine clearance 30-50 mL/min, bodyweight 60 kg or less, or concomitant medication with potent P-glycoprotein interaction. Efficacy outcomes included the primary endpoint of all-cause stroke or systemic embolism, ischaemic stroke, and all-cause mortality. Safety outcomes included the primary safety endpoint of major bleeding, fatal bleeding, intracranial haemorrhage, and gastrointestinal bleeding. This trial is registered with ClinicalTrials.gov, number NCT00781391. FINDINGS Between Nov 19, 2008 and Nov 22, 2010, 21 105 patients were recruited. Patients who met clinical criteria for dose reduction at randomisation (n=5356) had higher rates of stroke, bleeding, and death compared with those who did not have a dose reduction (n=15 749). Edoxaban dose ranged from 15 mg to 60 mg, resulting in a two-fold to three fold gradient of mean trough drug exposure (16·0-48·5 ng/mL in 6780 patients with data available) and mean trough anti-FXa activity (0·35-0·85 IU/mL in 2865 patients). Dose reduction decreased mean exposure by 29% (from 48·5 ng/mL [SD 45·8] to 34·6 ng/mL [30·9]) and 35% (from 24·5 ng/mL [22·7] to 16·0 ng/mL [14·5]) and mean anti-FXa activity by 25% (from 0·85 IU/mL [0·76] to 0·64 IU/mL [0·54]) and 20% (from 0·44 IU/mL [0·37] to 0·35 IU/mL [0·28]) in the higher-dose and lower-dose regimens, respectively. Despite the lower anti-FXa activity, dose reduction preserved the efficacy of edoxaban compared with warfarin (stroke or systemic embolic event: higher dose pinteraction=0·85, lower dose pinteraction=0·99) and provided even greater safety (major bleeding: higher dose pinteraction 0·02, lower dose pinteraction=0·002). INTERPRETATION These findings validate the strategy that tailoring of the dose of edoxaban on the basis of clinical factors alone achieves the dual goal of preventing excess drug concentrations and helps to optimise an individual patients risk of ischaemic and bleeding events and show that the therapeutic window for edoxaban is narrower for major bleeding than thromboembolism. FUNDING Daiichi-Sankyo Pharma Development.

Effects of high doses of simvastatin and atorvastatin on high-density lipoprotein cholesterol and apolipoprotein A-I ☆

A randomized, blinded, multicenter clinical trial was performed comparing low- and high-dose simvastatin (40 and 80 mg) with comparable doses of atorvastatin (20 and 40 mg) for effects on plasma concentrations of lipoproteins and apolipoprotein A-I over 12 weeks in 842 patients with elevated low-density lipoprotein cholesterol. The 2 agents reduced low-density lipoprotein cholesterol and triglycerides to a comparable degree, but simvastatin raised high-density lipoprotein cholesterol and apolipoprotein A-I more than atorvastatin, suggesting differences in metabolic effects of the 2 agents on plasma lipids and lipoproteins.

Concomitant use of cytochrome P450 3A4 inhibitors and simvastatin

The long-term safety profile of simvastatin, established over 10 years of clinical use, is excellent. The principal adverse effect of all inhibitors of hydroxymethylglutarate co-enzyme A (HMG-CoA) reductase, myopathy, is infrequent. Simvastatin is a substrate for cytochrome P450 3A4 (CYP3A4). CYP3A4 inhibitors can elevate the plasma concentration of HMG-CoA reductase inhibitory activity derived from simvastatin. Clinical experience has shown that concomitant use of potent inhibitors of CYP3A4 increase the risk for myopathy. Evaluation of data from clinical trials and postmarketing surveillance allows assessment of whether concomitant use of weaker CYP3A4 inhibitors, as represented by calcium channel blockers, has any effect on the risk of myopathy. Cases of myopathy in long-term clinical megatrials and in analyses of postmarketing adverse event reports have been surveyed. In megatrials with simvastatin, the overall incidence of myopathy was 0.025%. The proportion of patients developing myopathy who were taking a calcium channel blocker with simvastatin (1 of 3) was similar to the proportion of patients taking a calcium channel blocker overall. Among marketed-use adverse event reports, concomitant medication with a potent CYP3A4 inhibitor was more frequent among reports of myopathy than among reports of nonmusculoskeletal adverse events. No excess use of calcium channel blockers among myopathy reports was observed. We conclude that the overall risk of myopathy during treatment with simvastatin is very low. Potent CYP3A4 inhibitors, especially cyclosporine, significantly increase the risk. There is no evidence that weaker CYP3A4 inhibitors such as calcium channel blockers increase the risk.

Magnitude of alimentary lipemia is related to intima-media thickness of the common carotid artery in middle-aged men

Fat intake leads to generation of potentially atherogenic triglyceride-rich lipoproteins (TRL). To investigate the relationship between early atherosclerotic changes and accumulation of hepatic and intestinal TRL after oral fat intake, an estimate of the intima-media thickness (IMT) was made using ultrasound of the common carotid artery, and postprandial TRL was quantified during a standardized oral fat tolerance test in 30 healthy normo- and hypertriglyceridemic middle-aged men. At base line the expected positive association between the LDL cholesterol level and the IMT of the common carotid artery was observed (r = 0.53, P<0.01). In addition, postprandial plasma triglycerides, in particular those measured late (6 h) after intake of the test meal, correlated positively with the IMT (r = 0.44, P<0.05). Of note, this latter correlation was independent of both the LDL cholesterol and the fasting plasma triglyceride concentrations. In a multivariate analysis, 39% of the total variability for the common carotid IMT were explained by age, LDL cholesterol and the postprandial triglyceride level. In univariate analysis, few statistically significant relations were found between common carotid IMT and postprandial levels of chylomicron remnants, VLDL and VLDL remnants of different particle size, the latter determined by specific measurements of ApoB-48 and ApoB-100 in subfractions of TRL. Therefore, in healthy middle-aged men, elevated postprandial triglyceride levels might identify a metabolic state related to early atherosclerosis.