Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

Properly designed and conducted randomized controlled clinical trials (RCTs) are the premier tool for both testing mechanistic hypotheses and critically ascertaining the risks and benefits of a therapy or strategy for clinical care. The sample size of a trial is mainly a function of the rates of its primary objectives and the presumed influence of the intervention. Trials focusing on a primary outcome variable that can be readily quantified in each subject, such as blood pressure or plasma cholesterol levels, require substantially fewer participants and shorter durations to determine whether their predefined measurement is altered compared with a morbidity and mortality trial. Trials designed to determine whether clinical prognosis is altered by an intervention depend on the proportion of patients experiencing the predefined adverse clinical event(s) and often require 100s-fold–greater patient-time exposures to test their primary hypothesis and provide even modest information about safety. These resource-intense morbidity and mortality trials are generally only performed when information from observational studies as well as smaller mechanistic and surrogate- outcomes RCTs are so highly supportive of a favorable outcome that they justify the effort. Despite this understandable stacking of the cards with the best available information, many of the morbidity and mortality trials conducted to test for a potential favorable impact of an intervention conclude by not supporting the prestudy hypothesis-generating data.1 The lessons in humility offered by these neutral or negative outcomes trials underscore the importance of obtaining crucial risk–benefit data before widespread adoption of even an apparently favorable therapy.2 Articles pp 2506 and 2515 For rational therapeutic decision making, we would ideally like to have both a framework of reliable mechanistic information and robust clinical outcomes and safety data. Sometimes major clinical outcomes trials are designed with a complement of embedded ancillary trials to generate a more complete picture …

Studies have shown that phosphatidylinositol (PI) can stimulate reverse cholesterol transport by enhancing the flux of cholesterol into HDL and by promoting the transport of high density lipoprotein-cholesterol (HDL-C) to the liver and bile. The goal of this study was to determine the safety and therapeutic value of PI after oral administration to normolipidemic human subjects. We performed a randomized 2 week study in 16 normolipidemic subjects. Subjects received either 2.8 or 5.6 g of PI, with or without food. PI was well tolerated by all subjects. PI significantly affected the levels of HDL-C and triglyceride in the plasma of subjects receiving PI with food. The lower dose showed a 13% increase in HDL-C, whereas the high dose showed an increase of 18% over the 2 week period. Both low- and high-dose groups showed significant increases in plasma apolipoprotein A-I. The high dose of PI also decreased plasma triglycerides by 36% in the fed subjects. These data suggest that after only 2 weeks, PI may have a comparable therapeutic value to niacin, with negligible side effects.

Increasing levels of high-density lipoprotein (HDL) cholesterol through pharmacologic inhibition of cholesteryl ester transfer protein (CETP) is a potentially important strategy for prevention and treatment of cardiovascular disease (CVD). To use genetic variants in the CETP gene to assess potential risks and benefits of lifelong lower CETP activity on CVD and other outcomes. This prospective biobank study included 151 217 individuals aged 30 to 79 years who were enrolled from 5 urban and 5 rural areas of China from June 25, 2004, through July 15, 2008. All participants had baseline genotype data, 17 854 of whom had lipid measurements and 4657 of whom had lipoprotein particle measurements. Median follow-up of 9.2 years (interquartile range, 8.2-10.1 years) was completed January 1, 2016, through linkage to health insurance records and death and disease registries. Five CETP variants, including an East Asian loss-of-function variant (rs2303790), combined in a genetic score weighted to associations with HDL cholesterol levels. Baseline levels of lipids and lipoprotein particles, cardiovascular risk factors, incidence of carotid plaque and predefined major vascular and nonvascular diseases, and a phenome-wide range of diseases. Among the 151 217 individuals included in this study (58.4% women and 41.6% men), the mean (SD) age was 52.3 (10.9) years. Overall, the mean (SD) low-density lipoprotein (LDL) cholesterol level was 91 (27) mg/dL; HDL cholesterol level, 48 (12) mg/dL. CETP variants were strongly associated with higher concentrations of HDL cholesterol (eg, 6.1 [SE, 0.4] mg/dL per rs2303790-G allele; P = 9.4 × 10-47) but were not associated with lower LDL cholesterol levels. Within HDL particles, cholesterol esters were increased and triglycerides reduced, whereas within very low-density lipoprotein particles, cholesterol esters were reduced and triglycerides increased. When scaled to 10-mg/dL higher levels of HDL cholesterol, the CETP genetic score was not associated with occlusive CVD (18 550 events; odds ratio [OR], 0.98; 95% CI, 0.91-1.06), major coronary events (5767 events; OR, 1.08; 95% CI, 0.95-1.22), myocardial infarction (3118 events; OR, 1.14; 95% CI, 0.97-1.35), ischemic stroke (13 759 events; OR, 0.94; 95% CI, 0.86-1.02), intracerebral hemorrhage (6532 events; OR, 0.94; 95% CI, 0.83-1.06), or other vascular diseases or carotid plaque. Similarly, rs2303790 was not associated with any vascular diseases or plaque. No associations with nonvascular diseases were found other than an increased risk for eye diseases with rs2303790 (4090 events; OR, 1.43; 95% CI, 1.13-1.80; P = .003). CETP variants were associated with altered HDL metabolism but did not lower LDL cholesterol levels and had no significant association with risk for CVD. These results suggest that in the absence of reduced LDL cholesterol levels, increasing HDL cholesterol levels by inhibition of CETP may not confer significant benefits for CVD.

BackgroundObicetrapib is a highly selective cholesteryl ester transfer protein inhibitor that reduces low-density lipoprotein (LDL) cholesterol levels. The efficacy and safety of obicetrapib have not been fully characterized among patients at high risk for cardiovascular events.MethodsWe conducted a multinational, randomized, placebo-controlled trial involving patients with heterozygous familial hypercholesterolemia or a history of atherosclerotic cardiovascular disease who were receiving maximum tolerated doses of lipid-lowering therapy. Patients with an LDL cholesterol level of 100 mg per deciliter or higher or a non–high-density lipoprotein (HDL) cholesterol level of 130 mg per deciliter or higher, as well as those with an LDL cholesterol level of 55 to 100 mg per deciliter or a non-HDL cholesterol level of 85 to 130 mg per deciliter and at least one additional cardiovascular risk factor, were eligible for inclusion. The patients were randomly assigned in a 2:1 ratio to receive either 10 mg of obicetrapib once daily or matching placebo for 365 days. The primary end point was the percent change in the LDL cholesterol level from baseline to day 84.ResultsA total of 2530 patients underwent randomization; 1686 patients were assigned to receive obicetrapib and 844 to receive placebo. The mean age of the patients was 65 years, 34% were women, and the mean baseline LDL cholesterol level was 98 mg per deciliter. The least-squares mean percent change from baseline to day 84 in the LDL cholesterol level was −29.9% (95% confidence interval [CI], −32.1 to −27.8) in the obicetrapib group, as compared with 2.7% (95% CI, −0.4 to 5.8) in the placebo group, for a between-group difference of −32.6 percentage points (95% CI, −35.8 to −29.5; P<0.001). The incidence of adverse events appeared to be similar in the two groups.ConclusionsAmong patients with atherosclerotic cardiovascular disease or heterozygous familial hypercholesterolemia who were receiving maximum tolerated doses of lipid-lowering therapy and were at high risk for cardiovascular events, obicetrapib reduced LDL cholesterol levels by 29.9%. (Funded by NewAmsterdam Pharma; BROADWAY ClinicalTrials.gov number, NCT05142722.)

Despite large improvements in cardiovascular disease mortality, coronary heart disease (CHD) and stroke remain the leading causes of death in most nations around the world [1,101]. Statins are the foundation for cardiovascular prevention, with up to 50% reductions in cardiovascular risk with the more potent statins [2]. In both statin-treated and -untreated patients, low levels of high-density lipoprotein cholesterol (HDL-C) are an important predictor of subsequent cardiovascular risk [3,4]. In epidemiologic studies, each 1 mg/dl (0.03 mmol, or ~2–3%, depending on baseline HDL-C level) increase in HDL-C is associated with a 2–4% reduction in the risk of CHD events, independent of low-density lipoprotein cholesterol (LDL-C) levels [5]. Of the drugs currently on the market, niacin is the most effective at raising HDL-C (~25% at the 2-g dose), while statins and fibrates have more modest HDL-C-raising effects (3–10%) [6]. However, it is not clear that pharmacologically raising HDL-C per se with these agents reduces cardiovascular risk. A meta-ana lysis of HDL-C-raising drugs found that after adjusting for LDL-C-lowering, raising HDL-C (or lowering triglycerides) was not associated with further cardiovascular risk reduction [6]. Several classes of HDL-C-raising agents with novel mechanisms of action are under development [7]. Farthest along are the cholesteryl ester transfer protein (CETP) inhibitors. CETP mediates the transfer of cholesteryl esters from HDL to proatherogenic apolipoprotein B-lipoproteins for transportation of cholesterol back to the cells; blocking CETP increases levels of mature HDL-C particles. The first CETP inhibitor to move into clinical trials was torcetrapib (Pfizer, Inc). Despite large increases in HDL-C, development of torcetrapib was terminated due to excess mortality in the torcetrapib group of the large outcomes trial, Investigation of Lipid Level management to Understand its Impact in Atherosclerotic Events (ILLUMINATE). Increased mortality in the torcetrapib-treated group occurred despite a 72% increase in HDL-C and a 25% decrease in LDL-C [8]. Torcetrapib also had no benefit on atherosclerotic progression in two noninvasive imaging studies, despite similar lipid changes [9,10]. The adverse mortality effect of torcetrapib has been largely attributed to accelerated hypertension due to activation of the renin–angiotensin–aldosterone system through a non-CETP-dependent effect [11]. Other mechanisms, such as lack of HDL functionality and proinflammatory effects, have also been proposed to explain torcetrapib’s adverse effects. Two CETP inhibitors are still in development, anacetrapib and dalcetrapib. Neither agent has been found to increase blood pressure or influence the renin– angiotensin–aldosterone axis in studies to date [7]. The more potent CETP inhibitor, anacetrapib, comes from the same chemical class as torcetrapib and strongly binds to the CETP molecule. Added to optimal statin therapy, anacetrapib 100 mg has been shown to increase HDL-C by 138% and reduce LDL-C an additional 40%, with modest triglyceride-lowering effects [12]. The less potent dalcetrapib is from a different chemical class, binds reversibly to and induces a different conformational “Given the excess mortality caused by torcetrapib, it is unlikely that any CETP inhibitor will receive regulatory approval prior to the completion of the long-term cardiovascular end point trials...”

Low serum levels of high-density lipoprotein (HDL) are commonly encountered in patients with coronary artery disease (CAD). An example of this type of patient is a 42-year-old white man with a history of sudden-onset angina secondary to a 90% obstructive lesion along the proximal left anterior descending coronary artery. The family history was significant for his father, who died of a myocardial infarction (MI) at age 44 years. The patient underwent percutaneous transluminal angioplasty with stenting but developed in-stent restenosis. He underwent cutting balloon angioplasty and brachytherapy and was asymptomatic for approximately 6 months. The stent then developed a high-grade occlusion with recurrence of angina, and the patient required single-vessel bypass surgery. The patient’s baseline serum lipid profile revealed low-density lipoprotein (LDL) 128 mg/dL, HDL 27 mg/dL, and triglycerides 92 mg/dL. His lipoprotein(a), C-reactive protein, and homocysteine levels were normal. He was not hypertensive, had no impairment of glycemic control, and did not smoke. With a combination of simvastatin 40 mg and niacin (Niaspan; Kos Pharmaceuticals) 1000 mg daily, the patient’s lipid profile improved, with LDL 78 mg/dL, HDL 43 mg/dL, and triglycerides 60 mg/dL. Follow-up stress testing demonstrated normal myocardial perfusion, and the patient has been asymptomatic for 2 years. With few exceptions, low HDL is an independent risk factor for CAD in case-control and prospective observational studies. In contrast, high HDL levels are associated with longevity and are protective against the development of atherosclerotic disease. In the Framingham Study, risk for CAD increases sharply as HDL levels fall progressively below 40 mg/dL.1 In the Quebec Cardiovascular Study, for every 10% reduction in HDL, risk for CAD increased 13%.2 Many clinicians believe that low HDL is associated with increased CAD risk because it is a marker for hypertriglyceridemia and elevated remnant particle concentrations. The Prospective Cardiovascular Munster …

Elevated low-density lipoprotein (LDL) cholesterol and lowered high-density lipoprotein (HDL) cholesterol are important risk factors for cardiovascular disease. Accordingly, raising HDL cholesterol induced by cholesteryl ester transfer protein (CETP) inhibition is an attractive approach for reducing the residual risk of cardiovascular events that persist in many patients receiving low-density LDL cholesterol-lowering therapy with statins. The development of torcetrapib, a CETP inhibitor, was terminated due to its adverse cardiovascular effects. These adverse effects did not influence the mechanism of CETP inhibition, but affected the molecule itself. Therefore a CETP modulator, dalcetrapib, and a CETP inhibitor, anacetrapib, are in Phase III of clinical trials to evaluate their effects on cardiovascular outcomes. In the dal-VESSEL (dalcetrapib Phase IIb endothelial function study) and the dal-PLAQUE (safety and efficacy of dalcetrapib on atherosclerotic disease using novel non-invasive multimodality imaging) clinical studies, dalcetrapib reduced CETP activity by 50% and increased HDL cholesterol levels by 31% without changing LDL cholesterol levels. Moreover, dalcetrapib was associated with a reduction in carotid vessel-wall inflammation at 6 months, as well as a reduced vessel-wall area at 24 months compared with the placebo. In the DEFINE (determining the efficacy and tolerability of CETP inhibition with anacetrapib) clinical study, anacetrapib increased HDL cholesterol levels by 138% and decreased LDL cholesterol levels by 36%. In contrast with torcetrapib, anacetrapib had no adverse cardiovascular effects. The potential of dalcetrapib and anacetrapib in the treatment of cardiovascular diseases will be revealed by two large-scale clinical trials, the dal-OUTCOMES (efficacy and safety of dalcetrapib in patients with recent acute coronary syndrome) study and the REVEAL (randomized evaluation of the effects of anacetrapib through lipid modification, a large-scale, randomized placebo-controlled trial of the clinical effects of anacetrapib among people with established vascular disease) study. The dal-OUTCOMES study is testing whether dalcetrapib can reduce cardiovascular events and the REVEAL study is testing whether anacetrapib can reduce cardiovascular events. These reports are expected to be released by 2013 and 2017, respectively.

Therapy with cholesteryl ester transfer protein (CETP) inhibitors and diabetes risk

Epidemiological evidence strongly favors the notion that the risk of cardiovascular disease (CVD) is inversely related to the plasma high-density lipoprotein (HDL) cholesterol concentration.1 Low HDL cholesterol is still predictive of high CVD risk in subjects with low LDL cholesterol,2 as well as during statin treatment.3 These observational data and other studies, which show that HDL particles contain a large number of antioxidative, antiinflammatory, and antiproliferative proteins, underlie the generally held view that HDL particles have atheroprotective properties.1–5 However, evidence is accumulating supporting the concept that high HDL cholesterol levels do not always predict reduced CVD risk. The Incremental Decrease in End Points through Aggressive Lipid Lowering (IDEAL) trial and the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk case-control study revealed that (recurrent) CVD risk is not decreased in subjects with the highest HDL cholesterol and the greatest mean HDL particle size.6 More recently, a high HDL cholesterol, high C-reactive protein (CRP) subgroup of individuals at increased risk for a first cardiovascular event was identified in the community-dwelling Prevention of Renal and Vascular End-Stage Disease (PREVEND) cohort using the “outcome event mapping approach,” a graphical exploratory data analysis tool that has been originally developed by Corsetti et al.7 Applying this analytic method to the Thrombogenic Factors and Recurrent Coronary Events (THROMBO) postinfarction cohort, the presence of a subgroup …

Increased serum apolipoprotein (apo)B and associated LDL levels are well-correlated with an increased risk of coronary disease. ApoE⁻/⁻ and low density lipoprotein receptor (LDLr)⁻/⁻ mice have been extensively used for studies of coronary atherosclerosis. These animals show atherosclerotic lesions similar to those in humans, but their serum lipids are low in apoB-containing LDL particles. We describe the development of a new mouse model with a human-like lipid profile. Ldlr CETP⁺/⁻ hemizygous mice carry a single copy of the human CETP transgene and a single copy of a LDL receptor mutation. To evaluate the apoB pathways in this mouse model, we used novel short-interfering RNAs (siRNA) formulated in lipid nanoparticles (LNP). ApoB siRNAs induced up to 95% reduction of liver ApoB mRNA and serum apoB protein, and a significant lowering of serum LDL in Ldlr CETP⁺/⁻ mice. ApoB targeting is specific and dose-dependent, and it shows lipid-lowering effects for over three weeks. Although specific triglycerides (TG) were affected by ApoB mRNA knockdown (KD) and the total plasma lipid levels were decreased by 70%, the overall lipid distribution did not change. Results presented here demonstrate a new mouse model for investigating additional targets within the ApoB pathways using the siRNA modality.

Efficacy, Safety, Tolerability, and Pharmacokinetic Profile of Evacetrapib Administered as Monotherapy or in Combination With Atorvastatin in Japanese Patients With Dyslipidemia

High density lipoproteins (HDL) represent diverse subpopulations of particles that are heterogeneous in their physicochemical composition and functionality [1–3]. The cholesterol content of HDL particles, HDL cholesterol, has been used as a biomarker of atherosclerotic cardiovascular disease risk, and a target for pharmaceutical intervention [4]. Sincemany of these clinical trials were initiated, there have been transformational changes in our understanding of HDL biology and function such that increasing the cholesterol content of HDL is a failed therapeutic strategy [3, 4]. Among high-risk individuals treated with high-intensity statin therapy, low HDL-C has not been a consistent biomarker of cardiovascular events [5, 6]. In the Treating to New Targets (TNT) trial, atorvastatin-treated patients who achieved low density lipoprotein (LDL) cholesterol levels less than 70 mg/dL, recurrent cardiovascular events were higher among subgroups with low HDL cholesterol levels [7]. However, this association may have been confounded by the higher apolipoprotein B, the major protein on atherogenic lipoproteins, in the subgroups of patients with low HDL cholesterol levels. Low HDL cholesterol is also considered a biomarker of elevated triglyceride-rich lipoproteins as shown in Mendelian randomization studies [9]. In contrast to HDL cholesterol, HDL particle number is more strongly associated with increased cardiovascular risk in statin-treated individuals [6]. In JUPITER, a primary prevention trial of individuals at high risk for an initial cardiovascular event, on-trial levels of HDL cholesterol were not associated with cardiovascular risk in rosuvastatin-treated individuals [10]. In contrast, low ontrial levels of HDL particles were predictive of cardiovascular events. Cholesteryl ester transfer protein (CETP) is a plasma protein that facilitates exchange of neutral lipid between lipoprotein particles resulting in lower concentrations of VLDL and LDL particles without necessarily changing HDL particle concentration with the exception of dalcetrapib that had modest effects of increasing HDL particle concentration [10]. In a Mendelian randomization study that included 16,503 cases and 46,576 controls, the CETP polymorphism rs3764261 on chromosome 16q13 were associated with higher levels of HDL cholesterol (3.86 mg/dL per allele) and lower levels of LDL cholesterol (-1.16 mg/dL per allele) [8]. Carriers of the rs3764261 trait had a 4 % lower risk of myocardial infarction than non-carriers. Thus, CETP inhibition is a potential strategy for lowering cardiovascular events based on pharmacogenomics. Two clinical outcomes trials have been completed with CETP inhibitors [11, 12]. The ILLUSTRATE trial investigated the efficacy of the CETP inhibitor torcetrapib as a strategy to reduce the risk of recurrent events in atorvastatin-treated patients with stable coronary heart disease [11]. As compared with baseline values, torcetrapib increased HDL cholesterol by 72.1 %, and lowered LDL cholesterol and triglycerides by 24.9 and 9 %, respectively. Due to a higher mortality rate R. S. Rosenson (*) Mount Sinai Heart, Mount Sinai Icahn School of Medicine, New York, NY, USA e-mail: robert.rosenson@mssm.edu

This study was designed to establish the mechanism responsible for the increased apolipoprotein (apo) A-II levels caused by the cholesteryl ester transfer protein inhibitor torcetrapib. Nineteen subjects with low HDL cholesterol (<40 mg/dl), nine of whom were also treated with 20 mg of atorvastatin daily, received placebo for 4 weeks, followed by 120 mg of torcetrapib daily for the next 4 weeks. Six subjects in the nonatorvastatin cohort participated in a third phase, in which they received 120 mg of torcetrapib twice daily for 4 weeks. At the end of each phase, subjects underwent a primed-constant infusion of [5,5,5-(2)H(3)]L-leucine to determine the kinetics of HDL apoA-II. Relative to placebo, torcetrapib significantly increased apoA-II concentrations by reducing HDL apoA-II catabolism in the atorvastatin (-9.4%, P < 0.003) and nonatorvastatin once- (-9.9%, P = 0.02) and twice- (-13.2%, P = 0.02) daily cohorts. Torcetrapib significantly increased the amount of apoA-II in the alpha-2-migrating subpopulation of HDL when given as monotherapy (27%, P < 0.02; 57%, P < 0.003) or on a background of atorvastatin (28%, P < 0.01). In contrast, torcetrapib reduced concentrations of apoA-II in alpha-3-migrating HDL, with mean reductions of -14% (P = 0.23), -18% (P < 0.02), and -18% (P < 0.01) noted during the atorvastatin and nonatorvastatin 120 mg once- and twice-daily phases, respectively. Our findings indicate that CETP inhibition increases plasma concentrations of apoA-II by delaying HDL apoA-II catabolism and significantly alters the remodeling of apoA-II-containing HDL subpopulations.

OPINION article Front. Pharmacol., 14 July 2015Sec. Experimental Pharmacology and Drug Discovery Volume 6 - 2015 | https://doi.org/10.3389/fphar.2015.00145

Decreased high-density lipoprotein (HDL) cholesterol levels constitute a major risk factor for coronary heart disease; however, there are no therapies that substantially raise HDL cholesterol levels. Inhibition of cholesteryl ester transfer protein (CETP) has been proposed as a strategy to raise HDL cholesterol levels. We conducted a single-blind, placebo-controlled study to examine the effects of torcetrapib, a potent inhibitor of CETP, on plasma lipoprotein levels in 19 subjects with low levels of HDL cholesterol (<40 mg per deciliter [1.0 mmol per liter]), 9 of whom were also treated with 20 mg of atorvastatin daily. All the subjects received placebo for four weeks and then received 120 mg of torcetrapib daily for the following four weeks. Six of the subjects who did not receive atorvastatin also participated in a third phase, in which they received 120 mg of torcetrapib twice daily for four weeks. Treatment with 120 mg of torcetrapib daily increased plasma concentrations of HDL cholesterol by 61 percent (P<0.001) and 46 percent (P=0.001) in the atorvastatin and non-atorvastatin cohorts, respectively, and treatment with 120 mg twice daily increased HDL cholesterol by 106 percent (P<0.001). Torcetrapib also reduced low-density lipoprotein (LDL) cholesterol levels by 17 percent in the atorvastatin cohort (P=0.02). Finally, torcetrapib significantly altered the distribution of cholesterol among HDL and LDL subclasses, resulting in increases in the mean particle size of HDL and LDL in each cohort. In subjects with low HDL cholesterol levels, CETP inhibition with torcetrapib markedly increased HDL cholesterol levels and also decreased LDL cholesterol levels, both when administered as monotherapy and when administered in combination with a statin.