Anacetrapib Research Articles

Cholesteryl Ester Transfer Protein Inhibition With Anacetrapib Decreases Fractional Clearance Rates of High-Density Lipoprotein Apolipoprotein A-I and Plasma Cholesteryl Ester Transfer Protein.

Anacetrapib (ANA), an inhibitor of cholesteryl ester transfer protein (CETP) activity, increases plasma concentrations of high-density lipoprotein cholesterol (HDL-C), apolipoprotein A-I (apoA)-I, apoA-II, and CETP. The mechanisms responsible for these treatment-related increases in apolipoproteins and plasma CETP are unknown. We performed a randomized, placebo (PBO)-controlled, double-blind, fixed-sequence study to examine the effects of ANA on the metabolism of HDL apoA-I and apoA-II and plasma CETP. Twenty-nine participants received atorvastatin (ATV) 20 mg/d plus PBO for 4 weeks, followed by ATV plus ANA 100 mg/d for 8 weeks (ATV-ANA). Ten participants received double PBO for 4 weeks followed by PBO plus ANA for 8 weeks (PBO-ANA). At the end of each treatment, we examined the kinetics of HDL apoA-I, HDL apoA-II, and plasma CETP after D3-leucine administration as well as 2D gel analysis of HDL subspecies. In the combined ATV-ANA and PBO-ANA groups, ANA treatment increased plasma HDL-C (63.0%; P<0.001) and apoA-I levels (29.5%; P<0.001). These increases were associated with reductions in HDL apoA-I fractional clearance rate (18.2%; P=0.002) without changes in production rate. Although the apoA-II levels increased by 12.6% (P<0.001), we could not discern significant changes in either apoA-II fractional clearance rate or production rate. CETP levels increased 102% (P<0.001) on ANA because of a significant reduction in the fractional clearance rate of CETP (57.6%, P<0.001) with no change in CETP production rate. ANA treatment increases HDL apoA-I and CETP levels by decreasing the fractional clearance rate of each protein.

Abstract 009: CETP inhibitors Torcetrapib, Dalcetrapib, and Anacetrapib induce adipocyte-derived Aldosterone production through Nox and STAT3 activation

Large clinical trials indicated that CETP inhibitors increase HDL levels, but had unexpected side effects, such as hyperaldosteronism and hypertension. Some CETP inhibitors appear to accumulate in adipocytes, which are a source of aldosterone (Aldo). As such, we questioned whether CETP inhibitors influence Aldo production in adipocytes and assessed the role of reactive oxygen species (ROS) and STAT3 in this process. Human adipocytes (SW872), expressing CETP, were studied and compared to mouse adipocytes (3T3-L1), lacking CETP. Cells were treated with torcetrapib (TOR), dalcetrapib (DAL), or anacetrapib (ANA). To evaluate the role of ROS, cells were pre-treated with N-acetylcystein (NAC-ROS scavenger), ML171 and GKT136901 (Nox1/4 inhibitor, respectively), and Rotenone (Rot, mitochondrial ROS inhibitor). ROS were measured by lucigenin and amplex red. Aldo production, measured by ELISA, was induced by TOR (668pg/mL), DAL (348pg/mL) and ANA (434pg/mL) (p&lt;0.05 vs control 196pg/mL); an effect blocked by NAC. TOR, DAL and ANA increased superoxide (2-fold) and H2O2 (1.5-fold) production, and STAT3 phosphorylation (p&lt;0.05). TOR increased Nox1, 4 and 5 (2-fold); DAL increased Nox4 (2-fold) and, ANA increased Nox1 and 4 (3-fold). In TOR treated cells, Aldo production was inhibited by GKT (62%), ML171 (62%), Rot (45%), and S3I-201 (STAT3 inhibitor, 66%). DAL-induced Aldo production was blocked by ML171(62%) and S3I-201 (74%). In ANA treated cells, Aldo production was inhibited by GKT (94%), ML171 (83%), and Rot (66%). We also assessed effects of CETP inhibitors on chemerin production, a novel adipokine associated with hypertension. TOR, but not ANA or DAL stimulated chemerin production (331pg/mL vs control 154pg/mL p&lt;0.05); an effect blocked by GKT (95%) and S3I-201 (100%). In mouse adipocytes, TOR, DAL, and ANA induced Aldo (453pg/mL, 375pg/mL, and 445pg/mL vs cont 253pg/mL, p&lt;0.05) and ROS production (1.7-fold, p&lt;0.05). In conclusion, CETP inbitors induced aldosterone production in human and mouse adipocytes through redox-related mechanisms involving STAT3, Noxs and mitochondria. These novel findings have important clinical significance and may explain, in part, the hyperaldosteronism and hypertension reported in CETP clinical trials.

CETP inhibitors downregulate hepatic LDL receptor and PCSK9 expression in vitro and in vivo through a SREBP2 dependent mechanism

BackgroundCETP inhibitors block the transfer of cholesteryl ester from HDL-C to VLDL-C and LDL-C, thereby raising HDL-C and lowering LDL-C. In this study, we explored the effect of CETP inhibitors on hepatic LDL receptor (LDLR) and PCSK9 expression and further elucidated the underlying regulatory mechanism. ResultsWe first examined the effect of anacetrapib (ANA) and dalcetrapib (DAL) on LDLR and PCSK9 expression in hepatic cells in vitro. ANA exhibited a dose-dependent inhibition on both LDLR and PCSK9 expression in CETP-positive HepG2 cells and human primary hepatocytes as well as CETP-negative mouse primary hepatocytes (MPH). Moreover, the induction of LDLR protein expression by rosuvastatin in MPH was blunted by cotreatment with ANA. In both HepG2 and MPH ANA treatment reduced the amount of mature form of SREBP2 (SREBP2-M). In vivo, oral administration of ANA to dyslipidemic C57BL/6J mice at a daily dose of 50 mg/kg for 1 week elevated serum total cholesterol by approximately 24.5% (p < 0.05%) and VLDL-C by 70% (p < 0.05%) with concomitant reductions of serum PCSK9 and liver LDLR/SREBP2-M protein. Finally, we examined the in vitro effect of two other strong CETP inhibitors evacetrapib and torcetrapib on LDLR/PCSK9 expression and observed a similar inhibitory effect as ANA in a concentration range of 1–10 μM. ConclusionOur study revealed an unexpected off-target effect of CETP inhibitors that reduce the mature form of SREBP2, leading to attenuated transcription of hepatic LDLR and PCSK9. This negative regulation of SREBP pathway by ANA manifested in mice where CETP activity was absent and affected serum cholesterol metabolism.

In vivo effects of anacetrapib on preβ HDL: improvement in HDL remodeling without effects on cholesterol absorption

Cholesteryl ester transfer protein (CETP) transfers cholesteryl ester and triglyceride between HDL and apoB-containing lipoproteins. Anacetrapib (ANA), a reversible inhibitor of CETP, raises HDL cholesterol and lowers LDL cholesterol in dyslipidemic patients. We previously demonstrated that ANA increases macrophage-to-feces reverse cholesterol transport and fecal cholesterol excretion in hamsters, and increased preβ HDL-dependent cholesterol efflux via ABCA1 in vitro. However, the effects of ANA on in vivo preβ HDL have not been characterized. In vitro, ANA inhibited the formation of preβ, however in ANA-treated dyslipidemic hamsters, preβ HDL levels (measured by two-dimensional gel electrophoresis) were increased, in contrast to in vitro findings. Because changes in plasma preβ HDL have been proposed to potentially affect markers of cholesterol absorption with other CETP inhibitors, a dual stable isotope method was used to directly measure cholesterol absorption in hamsters. ANA treatment of hamsters (on either dyslipidemic or normal diet) had no effect on cholesterol absorption, while dalcetrapib-treated hamsters displayed an increase in cholesterol absorption. Taken together, these data support the notion that ANA promotes preβ HDL functionality in vivo, with no effects on cholesterol absorption.

Efficacy and safety of the cholesteryl ester transfer protein inhibitor anacetrapib in Japanese patients with dyslipidemia

ObjectiveThis study evaluated the effects of anacetrapib (ANA) on lipids and safety when administered as monotherapy or in combination with atorvastatin (ATV) in Japanese patients with dyslipidemia. MethodsPatients (n = 407) were randomized equally to 1 of 10 groups: placebo, ATV 10 mg, ANA 10, 40, 100, or 300 mg once daily, and the same ANA doses in combination with ATV 10 mg. Patients were treated with study medication for 8 weeks and followed for an additional 8 weeks, during which ANA was switched to placebo. ResultsFor the placebo and ANA monotherapy groups (10, 40, 100, and 300 mg), least squares mean percent changes from baseline at Week 8 for low-density lipoprotein cholesterol (LDL-C) calculated by the Friedewald equation were 3%, −12%, −27%, −32%, and −32%, respectively, and for high-density lipoprotein-cholesterol (HDL-C) were 1%, 56%, 116%, 134%, and 159%, respectively (p < 0.001 vs. placebo for all doses). All ANA doses co-administered with ATV 10 mg produced significantly greater LDL-C reductions and HDL-C increases compared with ATV 10 mg monotherapy. ANA was well tolerated, and dose-dependent relationships for adverse events were not observed across treatment groups. Changes from baseline in blood pressure and electrolytes were not significantly different between the active and control treatment groups. ConclusionANA, as monotherapy or co-administered with ATV, produced significant reductions in LDL-C and increases in HDL-C. ANA was generally well tolerated in Japanese patients with dyslipidemia.

Abstract 168: Effects of the CETP Inhibitor Anacetrapib on HDL3-to-HDL2 Transfer: Comparison of in Vitro and in Vivo Methodologies

Cholesteryl ester transfer protein (CETP) is a target for the treatment of dyslipidemia and coronary artery disease. In addition to the well-known effect of CETP to transfer CE from HDL to LDL and to VLDL, in vitro , CETP has been reported to transfer CE between small and large HDL particles (HDL2 and HDL3, respectively). We sought to understand how the CETP inhibitor anacetrapib (ANA) affects HDL3-to-HDL2 transfer under both in vitro and in vivo conditions. In vitro , ANA dose-dependently inhibited transfer of 3 H-CE from total HDL to LDL (IC50 30nM), and from isolated HDL3 to HDL2 particles (IC50 200nM). In human CETP transgenic mice, animals treated with a single dose of ANA (100mg/kg) displayed 80% maximal reduction in plasma CETP activity and a 22% increase in total HDL cholesterol. In animals treated with either vehicle or ANA, 3 H-CE-labeled HDL3 was injected intravenously and 3 H-tracer was monitored in lipoprotein fractions following injection. Animals treated with ANA showed an increase in the amount 3 H-tracer present in HDL2 compared to vehicle over time (20-70% increase across 6 hrs post 3 H-CE-HDL3 injection, P&lt;0.05 vs vehicle). The HDL2 CE pool was also increased with ANA treatment, and 3 H-cholesterol flux into HDL2 was increased with ANA treatment when adjusted to the change in pool size (at 2 and 4 hrs post 3H-CE-HDL3 injection). No change in HDL2 3 H-tracer was seen in C57BL6 mice (lacking CETP) treated with ANA. These results indicate that in contrast to in vitro findings, ANA increases flux of CE into HDL2 in vivo , a process which likely involves multiple pathways. Therefore, the in vitro phenomena of 1) HDL3-to-HDL2 transfer by CETP and 2) inhibition of this transfer by CETP inhibitors are not recapitulated in vivo . It is clear that in vivo approaches are necessary to understand the relevance of HDL3-to-HDL2 transfer in vivo , and to accurately study the effects of CETP inhibition on lipoprotein metabolism.

Changes in lipoprotein subfraction concentration and composition in healthy individuals treated with the CETP inhibitor anacetrapib

We investigated the effects of the cholesteryl ester (CE) transfer protein inhibitor anacetrapib (ANA) on plasma lipids, lipoprotein subfraction concentrations, and lipoprotein composition in 30 healthy individuals. Participants (n = 30) were randomized to ANA 20 mg/day, 150 mg/day, or placebo for 2 weeks. Changes in concentration of lipoprotein subfractions were assessed using ion mobility, and compositional analyses were performed on fractions separated by density gradient ultracentrifugation. ANA 150 mg/day versus placebo resulted in significant decreases in LDL-cholesterol (26%) and apo B (29%) and increases in HDL-cholesterol (82%). Concentrations of medium and small VLDL, large intermediate density lipoprotein (IDL), and medium and small LDL (LDL2a, 2b, and 3a) decreased whereas levels of very small and dense LDL4b were increased. There was enrichment of triglycerides and reduction of CE in VLDL, IDL, and the densest LDL fraction. Levels of large buoyant HDL particles were substantially increased, and there was enrichment of CE, apo AI, and apoCIII, but not apoAII or apoE, in the mid-HDL density range. Changes in lipoprotein subfraction concentrations and composition with ANA 20 mg/day were similar to those for ANA 150 mg/day but were generally smaller in magnitude. The impact of these changes on cardiovascular risk remains to be determined.

Abstract 9649: Lipid-modifying Effects of Anacetrapib in Patients with Lower versus Higher Baseline Levels Of HDL-C, LDL-C, And TG: Pre-Specified Subgroup Analyses of the DEFINE (Determining the Efficacy and Tolerability of CETP INhibition with AnacEtrapib) Trial

Purpose : Low HDL-C is a risk factor for coronary heart disease which partly accounts for residual risk despite statin therapy. After 24 weeks of treatment, the addition of anacetrapib (ANA), a cholesteryl ester transfer protein (CETP) inhibitor to statin therapy increased HDL-C by 138% and reduced LDL-C by 40% in a 1623 patient safety and lipid efficacy Phase III trial (DEFINE). Sub-group analyses were performed to determine the degree to which ANA raises HDL-C and lowers LDL-C in patients with low baseline HDL-C and in patients with diabetes and other subgroups. Methods: Percent placebo-corrected HDL-C increases and LDL-C decreases from baseline after 24 weeks of ANA, 100 mg/day, were compared among patients according to baseline HDL-C, LDL-C, and TG levels above or below the median and in patients with diabetes. Results: Median baseline HDL-C, LDL-C, and TG were 40 mg/dL, 81 mg/dL, and 128 mg/dL, respectively. ANA produced robust increases in HDL-C in patients with baseline HDL-C below (152%) and above (127%) the median. In the lowest baseline quartile of HDL-C (15 to 34 mg/dL) levels also increased to a mean on-treatment HDL-C of 85 mg/dL. The percent increase in HDL-C was similar in patients with lower vs. higher baseline TG levels. ANA increased HDL-C similarly in diabetics compared to non-diabetics (130% vs 150%) with a mean on-treatment HDL-C of 100 vs. 102 respectively. The percent reduction in LDL-C with ANA was generally similar in patients with lower vs higher baseline LDL-C, HDL-C or TG levels and in patients with or without diabetes. Conclusion: ANA robustly increased HDL-C in all patients especially those with low HDL-C. Reductions in LDL-C with ANA were independent of baseline LDL-C, HDL-C, or TG levels. The clinical impact of these lipid-modifying effects of ANA in these sub-groups will be assessed in REVEAL-HPS3/TIMI55, a 30,000 patient clinical outcomes trial.

Anacetrapib promotes reverse cholesterol transport and bulk cholesterol excretion in Syrian golden hamsters

Cholesteryl ester transfer protein (CETP) transfers cholesteryl ester (CE) and triglyceride between HDL and apoB-containing lipoproteins. Anacetrapib (ANA), a reversible inhibitor of CETP, raises HDL cholesterol (HDL-C) and lowers LDL cholesterol in dyslipidemic patients; however, the effects of ANA on cholesterol/lipoprotein metabolism in a dyslipidemic hamster model have not been demonstrated. To test whether ANA (60 mg/kg/day, 2 weeks) promoted reverse cholesterol transport (RCT), ³H-cholesterol-loaded macrophages were injected and (3)H-tracer levels were measured in HDL, liver, and feces. Compared to controls, ANA inhibited CETP (94%) and increased HDL-C (47%). ³H-tracer in HDL increased by 69% in hamsters treated with ANA, suggesting increased cholesterol efflux from macrophages to HDL. ³H-tracer in fecal cholesterol and bile acids increased by 90% and 57%, respectively, indicating increased macrophage-to-feces RCT. Mass spectrometry analysis of HDL from ANA-treated hamsters revealed an increase in free unlabeled cholesterol and CE. Furthermore, bulk cholesterol and cholic acid were increased in feces from ANA-treated hamsters. Using two independent approaches to assess cholesterol metabolism, the current study demonstrates that CETP inhibition with ANA promotes macrophage-to-feces RCT and results in increased fecal cholesterol/bile acid excretion, further supporting its development as a novel lipid therapy for the treatment of dyslipidemia and atherosclerotic vascular disease.

Efficacy and safety after cessation of treatment with the cholesteryl ester transfer protein inhibitor anacetrapib (MK-0859) in patients with primary hypercholesterolemia or mixed hyperlipidemia

This report describes the lipid and safety data collected during an off-drug period that followed 8 weeks of treatment with the cholesteryl ester transfer protein inhibitor, anacetrapib (ANA). A total of 589 patients with primary hypercholesterolemia or mixed hyperlipidemia were randomized to placebo, atorvastatin (ATV) 20 mg, and varying doses of ANA, provided as monotherapy or coadministered with ATV 20 mg daily. Patients were treated for 8 weeks, followed by an 8-week follow-up period, during which ANA was switched to placebo. At week 16 (8 weeks after ANA was stopped), persistent reductions in low-density lipoprotein cholesterol (LDL-C) were evident for the monotherapy groups receiving ANA 150 and 300 mg (-9.3% and -15.3%, respectively), and residual increases in high-density lipoprotein cholesterol (HDL-C) were observed for the monotherapy groups receiving ANA 40 mg (18.6%), 150 mg (40.5%), and 300 mg (43.4%). The effects on apolipoprotein B and apolipoprotein A-I were consistent with the changes observed for LDL-C and HDL-C, respectively. Corresponding residual changes in LDL-C and HDL-C were also noted in the ATV coadministration groups at the similar doses of ANA compared with ATV 20 mg alone. Residual plasma drug levels accompanied by reductions in cholesteryl ester transfer protein activity were observed at week 16 and may account for the alterations in plasma lipids 8 weeks after cessation of ANA.

Anacetrapib for Lipid Management: Safety in Numbers

Anacetrapib is a new drug that raises HDL levels and reduces LDL levels by inhibiting the cholesteryl ester transfer protein (CETP). Another CETP

Dalcetrapib preserves CETP-induced pre-β-HDL formation in vitro, in contrast to torcetrapib and anacetrapib

Dalcetrapib preserves CETP-induced pre-β-HDL formation in vitro, in contrast to torcetrapib and anacetrapib

Abstract: S3-31 NOVEL HDL RAISING THERAPIES FOR THE TREATMENT OF HIGH RISK CARDIOVASCULAR PATIENTS

CETP inhibitors block the transfer of cholesteryl ester from HDL-C to VLDL-C and LDL-C, thereby raising HDL-C and lowering LDL-C. In this study, we explored the effect of CETP inhibitors on hepatic LDL receptor (LDLR) and PCSK9 expression and further elucidated the underlying regulatory mechanism.We first examined the effect of anacetrapib (ANA) and dalcetrapib (DAL) on LDLR and PCSK9 expression in hepatic cells in vitro. ANA exhibited a dose-dependent inhibition on both LDLR and PCSK9 expression in CETP-positive HepG2 cells and human primary hepatocytes as well as CETP-negative mouse primary hepatocytes (MPH). Moreover, the induction of LDLR protein expression by rosuvastatin in MPH was blunted by cotreatment with ANA. In both HepG2 and MPH ANA treatment reduced the amount of mature form of SREBP2 (SREBP2-M). In vivo, oral administration of ANA to dyslipidemic C57BL/6J mice at a daily dose of 50 mg/kg for 1 week elevated serum total cholesterol by approximately 24.5% (p < 0.05%) and VLDL-C by 70% (p < 0.05%) with concomitant reductions of serum PCSK9 and liver LDLR/SREBP2-M protein. Finally, we examined the in vitro effect of two other strong CETP inhibitors evacetrapib and torcetrapib on LDLR/PCSK9 expression and observed a similar inhibitory effect as ANA in a concentration range of 1–10 μM.Our study revealed an unexpected off-target effect of CETP inhibitors that reduce the mature form of SREBP2, leading to attenuated transcription of hepatic LDLR and PCSK9. This negative regulation of SREBP pathway by ANA manifested in mice where CETP activity was absent and affected serum cholesterol metabolism.

Anacetrapib appears to be an advantage in dyslipidaemia

Anacetrapib appears to be an advantage in dyslipidaemia

M.544 Children's exposure to Tobacco smoke at the age of 8 years in an atherosclerosis prevention trial

This study evaluated the effects of anacetrapib (ANA) on lipids and safety when administered as monotherapy or in combination with atorvastatin (ATV) in Japanese patients with dyslipidemia.Patients (n = 407) were randomized equally to 1 of 10 groups: placebo, ATV 10 mg, ANA 10, 40, 100, or 300 mg once daily, and the same ANA doses in combination with ATV 10 mg. Patients were treated with study medication for 8 weeks and followed for an additional 8 weeks, during which ANA was switched to placebo.For the placebo and ANA monotherapy groups (10, 40, 100, and 300 mg), least squares mean percent changes from baseline at Week 8 for low-density lipoprotein cholesterol (LDL-C) calculated by the Friedewald equation were 3%, −12%, −27%, −32%, and −32%, respectively, and for high-density lipoprotein-cholesterol (HDL-C) were 1%, 56%, 116%, 134%, and 159%, respectively (p < 0.001 vs. placebo for all doses). All ANA doses co-administered with ATV 10 mg produced significantly greater LDL-C reductions and HDL-C increases compared with ATV 10 mg monotherapy. ANA was well tolerated, and dose-dependent relationships for adverse events were not observed across treatment groups. Changes from baseline in blood pressure and electrolytes were not significantly different between the active and control treatment groups.ANA, as monotherapy or co-administered with ATV, produced significant reductions in LDL-C and increases in HDL-C. ANA was generally well tolerated in Japanese patients with dyslipidemia.