In observational analyses, higher levels of high-density lipoprotein (HDL) cholesterol have been associated with a lower risk of coronary heart disease events. However, whether raising HDL cholesterol levels therapeutically reduces cardiovascular risk remains uncertain. Inhibition of cholesteryl ester transfer protein (CETP) raises HDL cholesterol levels and might therefore improve cardiovascular outcomes. We randomly assigned 15,871 patients who had had a recent acute coronary syndrome to receive the CETP inhibitor dalcetrapib, at a dose of 600 mg daily, or placebo, in addition to the best available evidence-based care. The primary efficacy end point was a composite of death from coronary heart disease, nonfatal myocardial infarction, ischemic stroke, unstable angina, or cardiac arrest with resuscitation. At the time of randomization, the mean HDL cholesterol level was 42 mg per deciliter (1.1 mmol per liter), and the mean low-density lipoprotein (LDL) cholesterol level was 76 mg per deciliter (2.0 mmol per liter). Over the course of the trial, HDL cholesterol levels increased from baseline by 4 to 11% in the placebo group and by 31 to 40% in the dalcetrapib group. Dalcetrapib had a minimal effect on LDL cholesterol levels. Patients were followed for a median of 31 months. At a prespecified interim analysis that included 1135 primary end-point events (71% of the projected total number), the independent data and safety monitoring board recommended termination of the trial for futility. As compared with placebo, dalcetrapib did not alter the risk of the primary end point (cumulative event rate, 8.0% and 8.3%, respectively; hazard ratio with dalcetrapib, 1.04; 95% confidence interval, 0.93 to 1.16; P=0.52) and did not have a significant effect on any component of the primary end point or total mortality. The median C-reactive protein level was 0.2 mg per liter higher and the mean systolic blood pressure was 0.6 mm Hg higher with dalcetrapib as compared with placebo (P<0.001 for both comparisons). In patients who had had a recent acute coronary syndrome, dalcetrapib increased HDL cholesterol levels but did not reduce the risk of recurrent cardiovascular events. (Funded by F. Hoffmann–La Roche; dal-OUTCOMES ClinicalTrials.gov number, NCT00658515.)

Following acute coronary syndrome (ACS), the risk for future cardiovascular events is high and is related to levels of low-density lipoprotein cholesterol (LDL-C) even within the setting of intensive statin treatment. Proprotein convertase subtilisin/kexin type 9 (PCSK9) regulates LDL receptor expression and circulating levels of LDL-C. Antibodies to PCSK9 can produce substantial and sustained reductions of LDL-C. The ODYSSEY Outcomes trial tests the hypothesis that treatment with alirocumab, a fully human monoclonal antibody to PCSK9, improves cardiovascular outcomes after ACS. This Phase 3 study will randomize approximately 18,000 patients to receive biweekly injections of alirocumab (75-150 mg) or matching placebo beginning 1 to 12 months after an index hospitalization for acute myocardial infarction or unstable angina. Qualifying patients are treated with atorvastatin 40 or 80 mg daily, rosuvastatin 20 or 40 mg daily, or the maximum tolerated and approved dose of one of these agents and fulfill one of the following criteria: LDL-C ≥ 70 mg/dL, non-high-density lipoprotein cholesterol ≥ 100 mg/dL, or apolipoprotein B ≥ 80 mg/dL. The primary efficacy measure is time to first occurrence of coronary heart disease death, acute myocardial infarction, hospitalization for unstable angina, or ischemic stroke. The trial is expected to continue until 1613 primary end point events have occurred with minimum follow-up of at least 2 years, providing 90% power to detect a 15% hazard reduction. Adverse events of special interest include allergic events and injection site reactions. Interim analyses are planned when approximately 50% and 75% of the targeted number of primary end points have occurred. ODYSSEY Outcomes will determine whether the addition of the PCSK9 antibody alirocumab to intensive statin therapy reduces cardiovascular morbidity and mortality after ACS.

Inclisiran, an siRNA administered twice-yearly, significantly reduced LDL cholesterol (LDL-C) in Phase III trials. Whether lowering LDL-C with inclisiran translates into a lower risk of cardiovascular (CV) events is not yet established. Patient-level, pooled analysis of ORION-9, −10 and −11, included patients with heterozygous familial hypercholesterolaemia, atherosclerotic CV disease (ASCVD), or ASCVD risk equivalent on maximally tolerated statin-therapy, randomized 1:1 to receive 284 mg inclisiran or placebo on Days 1, 90, and 6-monthly thereafter for 18 months. Prespecified exploratory endpoint of major cardiovascular events (MACEs) included non-adjudicated CV death, cardiac arrest, non-fatal myocardial infarction (MI), and fatal and non-fatal stroke, evaluated as part of safety assessments using a standard Medical Dictionary for Regulatory Activities basket. Although not prespecified, total fatal and non-fatal MI, and stroke were also evaluated. Mean LDL-C at baseline was 2.88 mmol/L. At Day 90, the placebo-corrected percentage reduction in LDL-C with inclisiran was 50.6%, corresponding to an absolute reduction of 1.37 mmol/L (both P < 0.0001). Among 3655 patients over 18 months, 303 (8.3%) experienced MACE, including 74 (2.0%) fatal and non-fatal MIs, and 28 (0.8%) fatal and non-fatal strokes. Inclisiran significantly reduced composite MACE [OR (95% CI): 0.74 (0.58–0.94)], but not fatal and non-fatal MIs [OR (95% CI): 0.80 (0.50–1.27)] or fatal and non-fatal stroke [OR (95% CI): 0.86 (0.41–1.81)]. This analysis offers early insights into the potential CV benefits of lowering LDL-C with inclisiran and suggests potential benefits for MACE reduction. These findings await confirmation in the larger CV outcomes trials of longer duration. AE, adverse event; HR, hazard ratio; LDL-C, low-density lipoprotein cholesterol; mRNA, messenger ribonucleic acid; OR, odds ratio; PCSK9, proprotein convertase subtilisin/kexin type 9; siRNA, small interfering ribonucleic acid.

Background: Patients with acute coronary syndrome are at risk for peripheral artery disease (PAD) events and venous thromboembolism (VTE). PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitors reduce lipoprotein(a) and low-density lipoprotein cholesterol (LDL-C) levels. Our objective was to ascertain whether PCSK9 inhibition reduces the risk of PAD events or VTE after acute coronary syndrome, and if such effects are related to levels of lipoprotein(a) or LDL-C. Methods: This was a prespecified analysis of the ODYSSEY OUTCOMES randomized clinical trial (Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome), which was conducted in 18 924 patients with recent acute coronary syndrome on intensive or maximum-tolerated statin treatment who were randomized to the PCSK9 inhibitor alirocumab or placebo. In a prespecified analysis, PAD events (critical limb ischemia, limb revascularization, or amputation for ischemia) and VTE (deep vein thrombosis or pulmonary embolism) were assessed. LDL-C was corrected (LDL-C _corrected ) for cholesterol content in lipoprotein(a). Results: At baseline, median lipoprotein(a) and LDL-C _corrected were 21 and 75 mg/dL, respectively; with alirocumab, median relative reductions were 23.5% and 70.6%, respectively. PAD events and VTE occurred in 246 and 92 patients, respectively. In the placebo group, risk of PAD events was related to baseline quartile of lipoprotein(a) ( P _trend =0.0021), and tended to associate with baseline quartile of LDL-C _corrected ( P _trend =0.06); VTE tended to associate with baseline quartile of lipoprotein(a) ( P _trend =0.06), but not LDL-C _corrected ( P _trend =0.85). Alirocumab reduced risk of PAD events (hazard ratio [HR], 0.69 [95% CI, 0.54–0.89]; P =0.004), with nonsignificantly fewer VTE events (HR, 0.67 [95% CI, 0.44–1.01]; P =0.06). Reduction in PAD events with alirocumab was associated with baseline quartile of lipoprotein(a) ( P _trend =0.03), but not LDL-C _corrected ( P _trend =0.50). With alirocumab, the change from baseline to Month 4 in lipoprotein(a), but not LDL-C _corrected , was associated with the risk of VTE and the composite of VTE and PAD events. Conclusions: In statin-treated patients with recent acute coronary syndrome, risk of PAD events is related to lipoprotein(a) level and is reduced by alirocumab, particularly among those with high lipoprotein(a). Further study is required to confirm whether risk of VTE is related to lipoprotein(a) level and its reduction with alirocumab. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01663402.