More Recent Headlines from the Late-breaking Clinical Trial Presentations at the American Heart Association Scientific Sessions 2

More Recent Headlines from the Late-breaking Clinical Trial Presentations at the American Heart Association Scientific Sessions -

Less Pessimism Called for When Interpreting the Results from VITAL Regarding Cardiovascular Benefits with Omega-3

 

By Kevin C Maki, PhD and Mary R Dicklin, PhD

 The primary results from the Vitamin D and Omega-3 Trial (VITAL) were recently presented at the late-breaking clinical trial sessions of the American Heart Association (AHA) meeting in Chicago, IL and simultaneously published in the New England Journal of Medicine.1  VITAL was a randomized, placebo-controlled trial of a 1 g/d fish oil capsule (Lovaza®/Omacor®) and 2000 IU/day vitamin D3 administered to 25,871 men ≥50 y of age and women ≥55 y of age.  The primary endpoints were major cardiovascular events (a composite of myocardial infarction [MI], stroke or death from cardiovascular causes) and invasive cancer of any type.  The key secondary endpoints were individual components of the composite cardiovascular endpoint, the composite endpoint plus coronary revascularization, site-specific cancers and death from cancer.  Patients were followed for a median of 5.3 y.  A discussion of the findings from the omega-3 and cardiovascular disease portion of the trial follows.

A major cardiovascular event occurred in 386 subjects in the omega-3 group and 419 in the placebo group (hazard ratio [HR] 0.92, 95% confidence interval [CI] 0.80 to 1.06, p = 0.24).1  The HR (95% CI) for the key secondary endpoints were 0.93 (0.82 to 1.04) for the composite plus coronary revascularization, 0.72 (0.59 to 0.90) for total MI, 1.04 (0.83 to 1.31) for total stroke, and 0.96 (0.76 to 1.21) for death from cardiovascular causes.  There were no excess risks of bleeding or other serious adverse events with the interventions.

In our opinion, the response to the results from VITAL has been unnecessarily pessimistic.2  It is true that the 8% reduction in the primary composite endpoint was not statistically significant.  However, as we have previously written, we believe that the failure of many of the omega-3 cardiovascular outcomes trials to show clear evidence of benefit can likely be attributed, in part, to the low dosages of omega-3 administered (most <1 g/d eicosapentaenoic acid [EPA] + docosahexaenoic acid [DHA]) and the groups in which the studies have been conducted (without elevated triglycerides [TG] and not limited to subjects with low omega-3 dietary intake).3  This was also the case in VITAL, where subjects at relatively low cardiovascular risk were administered a 1g/d fish oil concentrate capsule (providing 840 mg/d EPA + DHA) and the median fish intake in the study sample at baseline was well above the average intake in the US general population.1

 Results from the Reduction of Cardiovascular Events with Icosapent Ethyl-Intervention Trial (REDUCE-IT), presented in the same late-breaking clinical trials session at AHA and published simultaneously in New England Journal of Medicine, demonstrated that Vascepa® at a higher dosage of 4 g/d (~3700 mg/d EPA as icosapent ethyl) administered to subjects at higher risk with elevated TG (median of 216 mg/dL) resulted in a significant 25% reduction in the primary endpoint, the composite of cardiovascular death, nonfatal MI, nonfatal stroke, coronary revascularization or unstable angina.4  Unfortunately, an editorial that accompanied VITAL did not acknowledge the findings from REDUCE-IT, and in fact stated “…in the absence of additional compelling data, it is prudent to conclude that the strategy of dietary supplementation with either n-3 fatty acids or vitamin D as protection against cardiovascular events or cancer suffers from deteriorating VITAL signs.”2  It would seem that we do have “additional compelling data” in REDUCE-IT and that we should not abandon the idea that omega-3 fatty acids, when administered at higher dosages and to higher risk populations, reduces cardiovascular risk.  This adds to the biologic plausibility of the secondary outcomes for which benefits were observed.

In VITAL, endpoints that achieved nominal statistical significance included reductions in total MI (HR 0.72, 95% CI 0.59 to 0.90), total coronary heart disease (composite of MI, coronary revascularization and death from coronary heart disease; HR 0.83, 95% CI 0.71 to 0.97) and death from MI (HR 0.50, 95% CI 0.26 to 0.97) with omega-3 fatty acids vs. placebo.1  However, the editorial that accompanied VITAL emphasized the strong need for caution in interpreting “positive” results from secondary endpoints.2  While we agree that statistically significant secondary endpoints should not outweigh the null findings from the primary endpoint, it is also important that findings from secondary endpoints are not overlooked, particularly when they are in general agreement with results from prior studies.3,5-7  It is also notable that the subgroup with below-median fish intake at baseline showed statistically significant reductions of 19% and 40% in the primary outcome variable and total MI, respectively.1  This observation further supports the possibility that a relatively low dosage of EPA + DHA may have benefits in those with lower omega-3 fatty acid intakes.8

Our group published a meta-analysis of 14 randomized controlled trials that investigated the effects of omega-3 fatty acid supplementation on cardiac death, and reported that there was an 8% lower risk with omega-3 fatty acids vs. controls (and ~29% lower risk when dosages >1 g/d EPA + DHA were evaluated).7  Death from CHD in VITAL was not statistically significantly lower (HR 0.76, 95% CI 0.49 to 1.16).1  However, to further assess the potential for fatal CHD reduction with omega-3 fatty acid supplementation, we added the results from VITAL,1 along with other recently published trials,4,6 to a previous meta-analysis published by Aung and colleagues.5  This analysis demonstrated a statistically significant reduction in fatal CHD with omega-3 fatty acid interventions (relative risk 0.901, 95% CI 0.841 to 0.965, p = 0.003).9

Thus, it is our opinion that the null findings for the primary cardiovascular endpoint in VITAL need to be interpreted alongside the favorable findings from REDUCE-IT.  These results suggest the need for additional studies with higher dosages of EPA + DHA administered to high-risk populations.  We eagerly await the results from the last of the large-scale omega-3 fatty acid trials that is underway, The Outcomes Study to Assess Statin Residual Risk Reduction with Epanova in High Cardiovascular Risk Patients with Hypertriglyceridemia (STRENGTH), which enrolled subjects with elevated TG and below-average high-density lipoprotein cholesterol levels.10

References:

  1. Manson JE, Cook NR, Lee IM, et al. Marine n-3 fatty acids and prevention of cardiovascular disease and cancer. N Engl J Med. 2018; Epub ahead of print.

 

  1. Keaney JF, Jr., Rosen CJ. VITAL signs for dietary supplementation to prevent cancer and heart disease. N Engl J Med. 2018; Epub ahead of print.

 

  1. Maki KC, Dicklin MR. Omega-3 fatty acid supplementation and cardiovascular disease risk: glass half full or time to nail the coffin shut? Nutrients. 2018;10(7).

 

  1. Bhatt DL, Steg G, Miller M, et al. Cardiovascular risk reduction with icosapent ethyl for hypertriglyceridemia. N Engl J Med. 2018; Epub ahead of print.

 

  1. Aung T, Halsey J, Kromhout D, et al. Associations of omega-3 fatty acid supplement use with cardiovascular disease risks: meta-analysis of 10 trials involving 77917 individuals. JAMA Cardiol. 2018;3:225-234.

 

  1. ASCEND Study Collaborative Group. Effects of n-3 fatty acid supplements in diabetes mellitus. N Engl J Med. 2018; Epub ahead of print.

 

  1. Maki KC, Palacios OM, Bell M, Toth PP. Use of supplemental long-chain omega-3 fatty acids and risk for cardiac death: an updated meta-analysis and review of research gaps. J Clin Lipidol. 2018;11:1152-1160.

 

  1. Rimm EB, Appel LJ, Chiuve SE, et al. Seafood long-chain n-3 polyunsaturated fatty acids and cardiovascular disease: a science advisory from the American Heart Association. Circulation. 2018;138:e35-e47.

 

  1. Maki KC, Dicklin MR. Recent headlines from the late-breaking clinical trial presentations at the American Heart Association scientific sessions. REDUCE-IT – a landmark cardiovascular outcomes study of an omega-3 fatty acid. November 27, 2018. Available at https://mbclinicalacademy.com/headlines/.

 

  1. Nicholls SJ, Lincoff AM, Bash D, et al. Assessment of omega-3 carboxylic acids in statin-treated patients with high levels of triglycerides and low levels of high-density lipoprotein cholesterol: rationale and design of the STRENGTH trial. Clin Cardiol. 2018; 41:1281-1288.

 

 

 

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Recent Headlines from the Late-breaking Clinical Trial Presentations at the American Heart Association Scientific Sessions

Recent Headlines from the Late-breaking Clinical Trial Presentations at the American Heart Association Scientific Sessions -

REDUCE-IT – a Landmark Cardiovascular Outcomes Study of an Omega-3 Fatty Acid

 

By Kevin C Maki, PhD and Mary R Dicklin, PhD

 The primary results from the Reduction of Cardiovascular Events with Eicosapentaenoic Acid (EPA) – Intervention Trial (REDUCE-IT) were recently presented at the late-breaking clinical trial sessions of the American Heart Association meeting in Chicago, IL and simultaneously published in the New England Journal of Medicine.1,2  These results followed the topline result announced last month by Amarin, the maker of Vascepa® (icosapent ethyl), indicating an ~25% relative risk reduction in the primary composite endpoint of cardiovascular death, nonfatal myocardial infarction (MI), nonfatal stroke, coronary revascularization or unstable angina.3

 REDUCE-IT was a multicenter, randomized, double-blind trial that examined the effects of a high dosage of 4 g/d Vascepa providing ~3700 mg EPA vs. placebo on cardiovascular outcomes in 8179 statin-treated adults at high cardiovascular risk, followed for a median of 4.9 y.1  At entry, participants had an elevated fasting triglyceride (TG) level (median 216 mg/dL) and well-controlled low-density lipoprotein cholesterol (LDL-C; median of 75 mg/dL).  The primary endpoint occurred in 17.2% of patients on Vascepa vs. 22.0% of patients on placebo (hazard ratio [HR] 0.75, 95% confidence interval [CI] 0.68 to 0.83, p < 0.001).  The key secondary endpoint, which was a composite of cardiovascular death, nonfatal MI or nonfatal stroke, occurred in 11.2% of patients on Vascepa vs. 14.8% of patients on placebo (HR 0.74, 95% CI 0.65 to 0.83, p < 0.001).  The rates of all of the individual and composite endpoints (except for death from any cause) were all significantly lower with Vascepa than with placebo.  The overall rates of adverse events during the trial, and the rates of serious adverse events leading to discontinuation, were not significantly different between Vascepa and placebo groups.

A notable finding in REDUCE-IT was a 20% lower rate of cardiovascular death (p = 0.03).1  Our group previously conducted a meta-analysis of 14 randomized controlled trials that investigated the effects of omega-3 fatty acids on cardiac death, and found an 8% lower risk with omega-3 supplementation vs. controls.4  The effect was much larger (~29%) in studies that tested dosages >1 g/d EPA + docosahexaenoic acid (DHA).  Although REDUCE-IT did not include a coronary heart disease (CHD) death endpoint, the publication did include enough information to perform a rough calculation of it based on fatal MI, sudden cardiac death (SCD) and heart failure death.1  There were numerically lower incidence rates for both fatal MI and SCD in REDUCE-IT, but death from heart failure did not differ in the treatment arms, which suggests that the benefit to cardiovascular death was driven by fatal MI, SCD and fatal stroke, but not heart failure death.  To assess the possibility for detecting a benefit for fatal CHD with omega-3 fatty acids, we added our estimate from REDUCE-IT, to the results from a recent meta-analysis conducted by Aung et al.,5 along with data from A Study of Cardiovascular Events in Diabetes (ASCEND),6 and the recently published Vitamin D and Omega-3 Trial (VITAL).7  Doing this demonstrated a statistically significant reduction in fatal CHD with omega-3 fatty acids (details are below).

  • Aung meta-analysis5: 1301 of 39,017 participants for omega-3 and 1394 of 38,900 participants for control;
  • ASCEND6: 100 of 7740 participants for omega-3 and 127 of 7740 participants for control;
  • VITAL7: 37 of 12,933 participants for omega-3 and 49 of 12,938 participants for control;
  • REDUCE-IT (fatal MI + SCD)1: 74 of 4089 participants for omega-3 and 110 of 4090 participants for control;
  • When combined, this shows that CHD death occurred in 2.37% of 63,779 participants receiving omega-3 interventions and 2.64% of 63,668 participants in control conditions; the relative risk is 0.901 (95% CI 0.841 to 0.965, p = 0.003).

The result is also statistically significant without inclusion of the REDUCE-IT findings (relative risk 0.914, 95% CI 0.852 to 0.981, p = 0.013).  The robust results from REDUCE-IT, which included reductions in stroke as well as fatal and non-fatal CHD, suggest that low dosage in many of the prior studies was the reason for failure to demonstrate clear differences between the omega-3 and control groups in cardiovascular event rates.  Whether EPA is superior to DHA for risk reduction remains to be determined, and the results from the ongoing Outcomes Study to Assess Statin Residual Risk Reduction with Epanova® in High Risk Patients with Hypertriglyceridemia (STRENGTH), which are expected in 2019 or 2020, should provide information relevant to assessing this question.8  Epanova provides EPA + DHA in carboxylic acid (free fatty acid) form.

Some experts expressed surprise with the results from REDUCE-IT, because of the numerous unfavorable interpretations of results from other recently published trials and meta-analyses of the effects of omega-3 fatty acids on cardiovascular outcomes.5,6  While we agree that the magnitude of effect in REDUCE-IT, i.e., 25% reduction in risk, was somewhat larger than expected, as we previously expressed, in our opinion, the failure to show benefit in some of those previous studies was due to study design issues.9  Many of the prior studies tested low dosages (most administered just 1 g/d Omacor®/Lovaza® providing ~840 mg EPA + DHA), and they failed to examine the intervention in subjects with hypertriglyceridemia who would be expected to benefit most from a TG-lowering intervention.9  In another meta-analysis, our group found that medications that substantially lower TG (i.e., fibrates, niacin, omega-3 fatty acids) appeared to reduce cardiovascular disease risk in those with elevated TG, especially if accompanied by low high-density lipoprotein cholesterol (HDL-C) levels.10,11  The results from REDUCE-IT confirmed the larger benefit in those with elevated TG plus low HDL-C, with a reduction in the primary outcome of 38% in those with TG ≥200 mg/dL plus HDL-C ≤35 mg/dL, and 21% in those without this combination (p = 0.04 for interaction).

The REDUCE-IT authors suggested that at least some of the reduced risk of ischemic events may be explained by metabolic effects other than reduced TG levels.  This possibility is supported by the finding that the effect of the drug on primary and key secondary outcomes did not differ among those with and without achieved TG <150 mg/dL at one year.  There are several potential mechanisms through which EPA could lower risk beyond TG lowering, including, among others, reductions in inflammation, antiplatelet effects and plaque stabilization.  There was a statistically significant (p < 0.001) difference in high-sensitivity C-reactive protein (hs-CRP) response of 0.4 to 0.9 mg/L (21-40% depending on how calculated and timepoint) between the treatment arms favoring the active treatment group.1  Thus, it is possible, and in our view likely, that anti-inflammatory effects may have contributed to the observed benefits.

There have been concerns raised regarding some of the laboratory results in the trial.  For example, the use of the mineral oil placebo was problematic in that it was associated with increases in TG, LDL-C and non-HDL-C of 2.2%, 10.9%, and 10.4%, respectively at year 1, and apolipoprotein B and hs-CRP of 7.8% and 32.3%, respectively at 2 years.1,2  While not ideal, it is important to compare this to other clinical trials of prescription lipid-altering medications.  For example, among subjects taking placebo in the ODYSSEY Outcomes trial, there was an increase of approximately 12% in LDL-C during the treatment period (92 mg/dL to 103 mg/dL).12  Thus, it appears very unlikely that an adverse effect of the mineral oil placebo can explain more than a small fraction of the observed benefit.  In the Japan EPA Lipid Intervention Study (JELIS),13 a similar drug (1.8 g/d EPA from ethyl esters) reduced the primary cardiovascular endpoint by 19% compared with a no treatment control (not placebo).  The concordance in results between the trials provides compelling evidence that the benefit in REDUCE-IT is not artifactual.

Overall, it is our opinion that the results from REDUCE-IT are an important answer to the question of whether omega-3 fatty acids (EPA alone as icosapent ethyl in this instance) reduce cardiovascular risk when administered at a sufficiently high dosage to subjects with elevated TG who are at high cardiovascular risk.  This is unequivocally good news for patients and has been long-awaited given the large number of trials of low-dosage omega-3 fatty acids that had failed to produce clear evidence of cardiovascular benefit.  Additional trials are warranted to determine whether higher dosages of omega-3 fatty acids will also produce cardiovascular benefits in other population subgroups.

References:

  1. Bhatt DL, Steg G, Miller M, et al. Cardiovascular risk reduction with icosapent ethyl for hypertriglyceridemia. N Engl J Med. 2018; Epub ahead of print.

 

  1. Kastelein JJP, Stroes ESG. FISHing for the miracle of eicosapentaenoic acid. N Engl J Med. 2018; Epub ahead of print.

 

  1. Amarin Corporation. REDUCE-IT cardiovascular outcomes study of VASCEPA® (icosapent ethyl) capsules met primary endpoint. September 24, 2018. Available at https://investor.amarincorp.com/news-releases/news-release-details/reduce-ittm-cardiovascular-outcomes-study-vascepar-icosapent.

 

  1. Maki KC, Palacios OM, Bell M, Toth PP. Use of supplemental long-chain omega-3 fatty acids and risk for cardiac death: an updated meta-analysis and review of research gaps. J Clin Lipidol. 2018;11:1152-1160.

 

  1. Aung T, Halsey J, Kromhout D, et al. Associations of omega-3 fatty acid supplement use with cardiovascular disease risks: meta-analysis of 10 trials involving 77917 individuals. JAMA Cardiol. 2018;3:225-234.

 

  1. ASCEND Study Collaborative Group. Effects of n-3 fatty acid supplements in diabetes mellitus. N Engl J Med. 2018; Epub ahead of print.

 

  1. Manson JE, Cook NR, Lee IM, et al. Marine n-3 fatty acids and prevention of cardiovascular disease and cancer. N Engl J Med. 2018; Epub ahead of print.

 

  1. Nicholls SJ, Lincoff AM, Bash D, et al. Assessment of omega-3 carboxylic acids in statin-treated patients with high levels of triglycerides and low levels of high-density lipoprotein cholesterol: rationale and design of the STRENGTH trial. Clin Cardiol. 2018;41:1281-1288.

 

  1. Maki KC, Dicklin MR. Omega-3 fatty acid supplementation and cardiovascular disease risk: glass half full or time to nail the coffin shut? Nutrients. 2018;10(7).

 

  1. Maki JC, Guyton JR, Orringer CE, et al. Triglyceride-lowering therapies reduce cardiovascular disease event risk in subjects with hypertriglyceridemia. J Clin Lipidol. 2016;10:905-914.

 

  1. Maki KC, Dicklin MR. Do triglyceride-lowering drugs decrease risk of cardiovascular disease? Curr Opin Lipidol. 2017;28:374-379.

 

  1. Schwarz GG, Steg G, Szarek M, et al. Alirocumab and cardiovascular outcomes after acute coronary syndrome. N Engl J Med. 2018; Epub ahead of print.

 

  1. Yokoyama M, Origasa H, Matsuzaki M, et al. Effects of eicosapentaenoic acid on major coronary events in hypercholesterolaemic patients (JELIS): a randomized open-label, blinded endpoint analysis. Lancet. 2007;369:1090-1098.
Photo by Martin Brosy

Mechanisms Responsible for the Benefit on Cardiovascular Risk in the REDUCE-IT Trial

Mechanisms Responsible for the Benefit on Cardiovascular Risk in the REDUCE-IT Trial

By Kevin C Maki, PhD

 

Recently, we learned of the impressive topline results from the Reduction of Cardiovascular Events with Eicosapentaenoic Acid (EPA) – Intervention Trial (REDUCE-IT), which showed that Vascepa® (icosapent ethyl or EPA ethyl esters) lowered major adverse cardiovascular events (MACE) by nearly 25% (p < 0.001) when added to statin therapy in patients with hypertriglyceridemia at high cardiovascular risk.1  This is great news, since residual hypertriglyceridemia is common in statin-treated patients.2  Moreover, other relatively inexpensive evidence-based therapies such as ezetimibe have been shown to have only a modest effect on MACE risk (~10%) when added to statin therapy, consistent with the anticipated effect based on the degree of low-density lipoprotein cholesterol (LDL-C) lowering.  Proprotein convertase subtilisin kexin type 9 (PCSK9) inhibitors offer greater LDL-C reduction, but at a much higher cost.

 

The topline results from REDUCE-IT were a surprise to many who had concluded, based mainly on results from studies of omega-3 fatty acid interventions at low dosages in groups that did not have elevated average levels of triglycerides (TG), that omega-3 fatty acids were ineffective for lowering cardiovascular disease risk.3-7  I am looking forward to seeing the full set of results from REDUCE-IT, which will be presented at the 2018 American Heart Association Scientific Sessions and, hopefully, simultaneously published in a peer-reviewed journal.  These should provide more insight into the nature of the event reduction and possible lipid and non-lipid related drivers of the MACE reduction.

 

We know from the development program for Vascepa that it produces significant reductions in TG and TG-rich lipoprotein cholesterol levels.  In the ANCHOR trial, 4 g/d of Vascepa lowered the TG level by 21.5% relative to placebo in hypertriglyceridemic patients (median baseline TG 259 mg/dL) on statin therapy.8  In REDUCE-IT, the median baseline TG concentration was 216 mg/dL.  Therefore, if we assume a similar percentage reduction in TG, that would be 0.215 x 216 = 46.4 mg/dL.

 

There are several mechanisms through which long-chain omega-3 fatty acid interventions, (including EPA) may affect cardiovascular risk, of which TG lowering is only one.  Others include reducing myocardial fibrosis, lowering blood pressure and heart rate, reducing platelet activation and anti-inflammatory effects.9,10  Also, the physiologic effects of EPA, docosahexaenoic acid (DHA) and docosapentaenoic acid (DPA; an intermediate in the conversion of EPA to DHA) are not identical, so we cannot assume that the effects will be identical for interventions that vary in the proportions of these fatty acids.  However, my view is that a large fraction of the benefit in REDUCE-IT is likely to be attributable to TG lowering based on two lines of evidence.

 

First, a meta-analysis conducted by my colleagues and I of the effects of TG-lowering drug therapies showed a modest effect overall (12% risk reduction in 10 trials), but larger effects in subgroups with TG ≥150 mg/dL (18% risk reduction), especially if accompanied by low high-density lipoprotein cholesterol (HDL-C; 29% risk reduction).11,12  The subjects in REDUCE-IT all had elevated TG and a large percentage likely also had low HDL-C.

 

Second, a meta-regression by Jun et al. showed that each 0.1 mmol/L (8.85 mg/dL) reduction in TG with fibrate therapy was associated with a reduction of 5% in MACE risk.13  The approximate reduction in TG relative to placebo of 46.4 mg/dL in REDUCE-IT would therefore be expected to produce 5.24 units (46.4/8.85 = 5.24) of 5% MACE reduction, i.e., 1 - 0.955.24= 0.236 or 23.6% MACE reduction.  The biologic plausibility of a benefit being attributable to TG reduction is supported not only by evidence from prior randomized, controlled trials of TG-lowering drug therapies (albeit in subgroups), but also by studies showing that genetic variants associated with reduced TG (and TG-rich lipoprotein cholesterol) are associated with lower cardiovascular risk. 

 

My colleagues and I view the results from REDUCE-IT as a major positive development for patient care.  We eagerly anticipate the full REDUCE-IT results, as well as those from additional studies that, we hope, will provide greater insight into the mechanisms responsible for reduced MACE risk in the REDUCE-IT trial.

 

References:

  1. Amarin Corporation. REDUCE-IT cardiovascular outcomes study of VASCEPA® (icosapent ethyl) capsules met primary endpoint. September 24, 2018. Available at https://investor.amarincorp.com/news-releases/news-release-details/reduce-ittm-cardiovascular-outcomes-study-vascepar-icosapent.

 

  1. Fan W, Philip S, Granowitz C, et al. Prevalence and predictors of residual hypertriglyceridemia according to statin use in US adults. J Clin Lipidol. 2018;12:530-531.

 

  1. Maki KC, Dicklin MR. Omega-3 fatty acid supplementation and cardiovascular disease risk: glass half full or time to nail the coffin shut? Nutrients. 2018;10:864.

 

  1. Aung T, Halsey J, Kromhout D, et al. Associations of omega-3 fatty acid supplement use with cardiovascular disease risks: Meta-analysis of 10 trials involving 77,917 individuals. JAMA Cardiol. 2018;3:224-234.

 

  1. Alexander DD, Miller PE, Van Elswyk ME, et al. A meta-analysis of randomized controlled trials and prospective cohort studies of eicosapentaenoic and docosahexaenoic long-chain omega-3 fatty acids and coronary heart disease risk. Mayo Clin Proc. 2017;29:15-29.

 

  1. Abdelhamid AS, Brown TJ, Brainard JS, et al. Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev. 2018;7:CD003177.

 

  1. The ASCEND Study Collaborative Group. Effects of n-3 fatty acid supplements in diabetes mellitus. N Engl J Med. 2018 [Epub ahead of print].

 

  1. Ballantyne CM, Bays HE, Kastelein JJ, et al. Efficacy and safety of eicosapentaenoic acid ethyl ester (AMR 101) therapy in statin-treated patients with persistent high triglycerides (from the ANCHOR study). Am J Cardiol. 2012;110:984-992.

 

  1. Mozaffarian D, Wu JH. Omega-3 fatty acids and cardiovascular disease: effects on risk factors, molecular pathways, and clinical events. J Am Coll Cardiol. 2011;58:2047-2067.

 

  1. Mozaffarian D, Prineas RJ, Stein PK, Siscovick DS. Dietary fish and n-3 fatty acid intake and cardiac electrocardiographic parameters in humans. J Am Coll Cardiol. 2006;38:478-484.

 

  1. Maki KC, Guyton JR, Orringer CE, et al. Triglyceride-lowering therapies reduce cardiovascular disease event risk in subjects with hypertriglyceridemia. J Clin Lipidol. 2016;10:905-914.

 

  1. Maki KC, Dicklin MR. Do triglyceride-lowering drugs decrease risk of cardiovascular disease? Curr Opin Lipidol. 2017;28:374-379.

 

  1. Jun M, Foote C, Lv J, et al. Effects of fibrates on cardiovascular outcomes: a systematic review and meta-analysis. Lancet. 2010;375:1875-1884.

 

 

 

Photo by Vincent Botta

Topline Results from REDUCE-IT Show a Significant Reduction in Cardiovascular Outcomes with Omega-3 Fatty Acid

Topline Results from REDUCE-IT Show a Significant Reduction in Cardiovascular Outcomes with Omega-3 Fatty Acid

By Kevin C Maki, PhD and Mary R Dicklin, PhD

 

Exciting topline results from the Reduction of Cardiovascular Events with Eicosapentaenoic Acid (EPA) – Intervention Trial (REDUCE-IT) were recently announced by Amarin, the maker of Vascepa®.1 The full results are scheduled to be presented on November 10, 2018 at the American Heart Association’s (AHA) Scientific Sessions in Chicago, IL.  REDUCE-IT was a randomized, controlled trial that examined the effects of 4 g/d Vascepa vs. placebo on cardiovascular outcomes in statin-treated adults at elevated cardiovascular risk.2   Topline results indicated an ~25% relative risk reduction (p < 0.001) in the primary composite endpoint of the first occurrence of a major adverse cardiovascular event, including cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, coronary revascularization, or unstable angina requiring hospitalization, after a median follow-up of 4.9 y.1

 

These results will take some by surprise, based on the abundance of unfavorable interpretations of the effects of omega-3 fatty acids on cardiovascular outcomes from other recently published trials and meta-analyses.3,4  However, as my colleagues and I previously speculated,5 a failure to show benefit in some of those other studies has likely been due, at least in part, to study design issues, including administration of low dosages and absence of a clear pathophysiologic target for the intervention.  Unlike previous studies, many of which gave 1 g/d Omacor®/Lovaza®, containing ~850 mg EPA + docosahexaenoic acid (DHA),6 in REDUCE-IT subjects received a high dosage of 4 g/d Vascepa (roughly 3,700 mg of EPA).Subjects in REDUCE-IT were also required to have elevated baseline triglycerides (TG) of ≥150 mg/dL and <500 mg/dL (lower limit later changed to ≥200 mg/dL), resulting in a median baseline TG level of 216 mg/dL.  Results from our meta-analysis suggested that medications which substantially lower TG reduce cardiovascular risk in those with elevated TG, especially if accompanied by low high-density-lipoprotein cholesterol.7  Thus, REDUCE-IT directly addressed the issue of TG-lowering as a target of therapy.

 

Our separate meta-analysis of 14 randomized controlled trials that investigated the effects of omega-3 fatty acids on cardiac death showed an 8% lower risk with omega-3 supplementation vs. controls, although the effect was much larger (29%) in studies where the dosage employed was >1 g/d of EPA + DHA.8  It is uncertain whether REDUCE-IT will have enough cardiac deaths to show a benefit for that outcome, although it should add a substantial number of events to the aggregate database of studies using higher dosages. 

 

Results from another large-scale clinical trial of omega-3 fatty acids, the Vitamin D and Omega-3 Trial (VITAL), are also scheduled to be presented at AHA.  In VITAL, subjects received 1 g/d of Omacor/Lovaza and were not required to have elevated TG levels at baseline.9  The results from VITAL and another recently reported trial (A Study of Cardiovascular Events in Diabetes; ASCEND)4 will facilitate a more complete assessment of the effects of low-dosage EPA + DHA on the risk of cardiac death, which has important public health implications.

 

The Outcomes Study to Assess Statin Residual Risk Reduction with Epanova in High Cardiovascular Risk Patients with Hypertriglyceridemia (STRENGTH) is another high-dosage study (4 g/d) of the carboxylic acids (free fatty acids) form of EPA + DHA, and the last of the large-scale omega-3 trials underway.  Subjects in STRENGTH were required to not only have elevated TG (≥180 mg/dL and <500 mg/dL), but also to have low levels of high-density lipoprotein cholesterol (<47 mg/dL for women and <42 mg/dL for men).10  STRENGTH is scheduled to complete in the fall of 2019.

 

References:

  1. Amarin Corporation. REDUCE-IT cardiovascular outcomes study of VASCEPA® (icosapent ethyl) capsules met primary endpoint. September 24, 2018. Available at https://investor.amarincorp.com/news-releases/news-release-details/reduce-ittm-cardiovascular-outcomes-study-vascepar-icosapent.

 

  1. Bhatt DL, Steg PG, Brinton EA, et al. Rationale and design of REDUCE-IT: reduction of cardiovascular events with icosapent ethyl-intervention trial. Clin Cardiol. 2017;40:138-148.

 

  1. Aung T, Halsey J, Kromhout D, et al. Associations of omega-3 fatty acid supplement use with cardiovascular disease risks: meta-analysis of 10 trials involving 77917 individuals. JAMA Cardiol. 2018;3:225-234.

 

  1. ASCEND Study Collaborative Group. Effects of n-3 fatty acid supplements in diabetes mellitus. N Engl J Med. 2018; Epub ahead of print.

 

  1. Maki KC, Dicklin MR. Omega-3 fatty acid supplementation and cardiovascular disease risk: glass half full or time to nail the coffin shut? Nutrients. 2018;10(7).

 

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