Why Some Cholesterol Drugs Prevent Heart Attacks and Others Do Not

For decades, researchers believed that to prevent heart disease they needed to be able to improve patients' blood test numbers. Therefore, it was thought that if a medication could increase "good" cholesterol or lower "bad" cholesterol it would help keep patients safe from heart attacks.

Over the years there have been several large clinical trials that proved this is not always true. Multiple medications have been made and tested that have greatly improved blood test numbers without reducing heart attacks or strokes. When researchers looked at these trials together the key focus began to be not just whether a medication changes your blood test numbers, but if lowering cholesterol can prevent heart attacks and strokes. The answer depends heavily on which cholesterol particles a medication lowers, by how much, and for how long.

In this blog we will review over twenty years of major cardiovascular trials to explain why some cholesterol medications work, why others failed, and how current research views heart health and risks today.

What Does MACE Mean in a Heart Study?

To understand why some medication trials succeed and others fail, it helps to understand how medical studies measure success.

In heart health studies, researchers track two very different types of results:

• Surrogate Endpoints (Lab Markers): These are lab test numbers, such as total cholesterol, HDL, LDL, or triglycerides. Learn more about cholesterol markers here.
• Hard Clinical Outcomes (MACE): This stands for Major Adverse Cardiovascular Events. MACE includes real-life events like heart attacks, strokes, emergency heart surgeries, and deaths from heart disease.

Lab numbers tell doctors how a drug affects your blood. That said, the success of a heart health medication is ultimately judged by MACE outcomes. This means a medication is only considered successful if it reduces actual heart events, regardless of how good it makes a lab report look.

Three Ways to Change a Cholesterol Panel

Over the years, researchers have tried three main strategies to improve blood cholesterol and lower heart risk:

• Lowering LDL (Low-Density Lipoprotein): Often called "bad" cholesterol because high levels build up inside arterial walls.
• Raising HDL (High-Density Lipoprotein): Often called "good" cholesterol because it carries excess fat back to the liver to be removed from the body.
• Lowering Triglycerides: A common type of fat in the blood linked to heart disease and metabolic health.

In the beginning, all three strategies were thought to have potential for heart health medications. However, large clinical trials testing these three separate medication paths produced very different results.

Where Statins Fit: The Benchmark for Heart Protection

To test new heart drugs, researchers use statins (such as atorvastatin or simvastatin) as the standard reference point. Statins work by helping the liver clear plaque-causing cholesterol particles from the bloodstream. Across dozens of massive studies, statins have consistently lowered both cholesterol numbers and heart events. Statins are known to be effective and well tested so almost every trial discussed in this blog tested a new drug added on top of standard statin therapy.

The question these trials asked was not just whether a new medicine worked alone, but whether adding it to a statin provided any extra heart protection.

Raising HDL Cholesterol: The CETP Trials

One major strategy researchers tested was blocking a protein called CETP (cholesteryl ester transfer protein) to raise HDL cholesterol. To read the full history of how these drugs were developed and tested, see our companion blog: The History of CETP Inhibitors.

Two major CETP medication trials tested whether raising HDL on top of statin therapy would lower heart events:

• Dalcetrapib (dal-OUTCOMES Trial): Tested in 15,871 patients after a recent heart attack or chest pain event. Dalcetrapib raised HDL cholesterol by 30% to 40% but had minimal effect on LDL. After nearly three years, the drug showed no reduction in heart events.
• Evacetrapib (ACCELERATE Trial): Tested in 12,092 high-risk patients. Evacetrapib approximately doubled HDL cholesterol and lowered LDL cholesterol by over 30%. Even with these impressive lab numbers, experts stopped the trial early because the drug did not lower heart attacks, strokes, or heart deaths compared to statin therapy alone.

Raising HDL Cholesterol: The Niacin Trials

To try to understand if the failure of CETP drugs was just because of the one drug class, researchers looked at other ways to raise HDL cholesterol. Niacin (vitamin B3) is a different compound that also raises HDL.

The AIM-HIGH trial tested extended-release niacin added to standard statin therapy (simvastatin) in 3,414 patients with established heart disease and low HDL levels. Niacin raised HDL cholesterol levels by 25% compared to 12% in the placebo group (simvastatin plus a matching placebo tablet containing a small 50mg dose of immediate-release niacin to mimic the skin-flushing side effect).

Despite this increase, the trial was stopped about 18 months early for lack of benefit. Major heart events occurred in 16.4% of patients taking niacin and 16.2% of patients taking placebo showing no statistically significant difference, meaning there was no effect. Additionally, researchers noted a small increase of ischemic strokes in the niacin group (1.6% vs. 0.9%).

Does Raising HDL Cholesterol Prevent Heart Attacks?

After testing the two different drug classes including CETP inhibitors and niacin researchers concluded the exact same result. Both drug types raised "good" HDL cholesterol dramatically, but neither reduced heart attacks or strokes when added to statin therapy. The evidence allowed researchers to conclude that raising HDL cholesterol alone does not automatically protect your heart.

Lowering Triglycerides: The Fibrate Question

Another major strategy researchers tested was lowering blood fats called triglycerides using a class of medications called fibrates.

The ACCORD-Lipid trial tested fenofibrate added to statin therapy (simvastatin) in 5,518 patients with type 2 diabetes. The results showed lowered triglycerides and raised HDL, but the annual rate of major heart events was 2.2% with fenofibrate versus 2.4% with placebo (inactive pill plus simvastatin). Therefore, adding fenofibrate to statin therapy did not lower the overall heart risk.

Fenofibrate did show a slight trend toward benefit in a specific group of patients with both very high triglycerides and very low HDL. However, researchers emphasize that this subgroup interaction was not statistically significant, meaning it remains an unproven theory and not a confirmed fact.

Important Safety Note: Fenofibrate does have approved and effective medical uses such as treating severe hypertriglyceridemia to prevent pancreatitis (inflammation of the pancreas). A trial showing no added heart health benefit in the general statin-treated patient population does not mean the drug has no purpose. Never stop taking a prescribed medication without talking to your doctor.

What About Vascepa (Icosapent Ethyl)?

Vascepa (icosapent ethyl) is one of the most notable exceptions to the idea that lowering triglycerides alone does not reduce cardiovascular risk. Its clinical trial results raised important questions about whether benefits may come from mechanisms beyond triglyceride reduction.

The REDUCE-IT trial followed over 8,000 statin-treated patients with elevated triglycerides and found that adding icosapent ethyl reduced major cardiovascular events by approximately 25%. This result differed from previous fibrate studies and sparked significant scientific debate regarding the exact mechanism of benefit.

Researchers continue to study whether the cardiovascular protection seen with icosapent ethyl comes primarily from triglyceride reduction, anti-inflammatory effects, plaque stabilization, or other biological mechanisms.

The potential role of inflammation in heart disease is particularly interesting. Researchers now recognize that atherosclerosis is driven not only by the accumulation of ApoB-containing particles, but also by chronic inflammation within the artery wall. Evidence for the importance of inflammation comes from low-dose colchicine studies such as Lodoco, where reductions in major cardiovascular events were observed despite minimal effects on cholesterol or ApoB levels. These findings suggest that lowering cardiovascular risk may involve more than improving lipid measurements alone.

Regardless of the exact mechanism, REDUCE-IT demonstrated a reduction in cardiovascular events rather than simply an improvement in laboratory measurements.

This finding reinforces one of the central lessons of cardiovascular research: the most important question is not whether a medication changes cholesterol or triglyceride numbers, but whether it reduces heart attacks, strokes, and other major cardiovascular events.

Please note, Vascepa is now available as a generic.

What the Unsuccessful Trials Had in Common

When researchers examined the failed CETP, niacin, and fibrate trials, they noticed a pattern.

Researchers saw that none of the studied medications were able to reduce the overall number of dangerous, plaque-causing particles in the blood. The medications may have changed the cholesterol weight being carried inside certain packages (like HDL), but they left the overall count of harmful particles unchanged.

What Is ApoB and What Does It Measure?

To be able to understand why the overall count of harmful particles matter, it is helpful to take a closer look at Apolipoprotein B (ApoB).

ApoB is a protein tag that attaches to the surface of dangerous, plaque-causing cholesterol in your blood (including LDL, VLDL, and IDL). Every harmful plaque-causing particle carries exactly one ApoB tag which means measuring ApoB gives researchers an exact count of how many dangerous particles are floating in your bloodstream.

• Standard LDL-C Tests: Measure the total weight of cholesterol carried inside LDL packages.
• ApoB Tests: Count the total number of physical packages.

To better understand this, imagine two people with the exact same weight of LDL cholesterol on a blood test.

The first person might have a small number of large, fat-filled packages.

The second person might have a massive amount of tiny packages.

The second person will have a much higher ApoB count and therefore a higher risk of plaque building up in their arteries. Remember: ApoB counts the total number of physical packages, not the total weight of all the packages together.

Evaluating CETP Drugs Through the ApoB Lens

Re-evaluating the earlier CETP trials with the new ApoB particle count method helped explain the previous trials mixed outcomes:

• Evacetrapib (ACCELERATE Trial): Lowered LDL cholesterol weight, but the decrease in ApoB particle counts was low and approximately comparable to adding ezetimibe to a statin.
• Anacetrapib (REVEAL Trial): Tested in 30,449 patients over four years. Anacetrapib was found to reduce major heart events by about 9% when added to atorvastatin therapy. Researchers have linked this modest success to the medication's ability to lower ApoB-containing particles and LDL cholesterol rather than its ability to raise HDL.

Why Statins Are the Clearest Case of the Pattern

After all this research statins remain the main foundational medication of heart health because they can directly target ApoB-containing particles.

By removing ApoB packages from the blood, statins consistently reduce both particle number counts and heart events. They show that reducing plaque-causing particles reduces patient heart health risks.

To learn more about how standard cholesterol treatments work, read our comprehensive overview on how statins work and different statin types.

Does It Matter Which Statin I Take?

Patients often wonder if one specific statin is better than another, however prescribers do not view different statins with a ranking or graded system.

When choosing or adjusting a statin, a prescriber carefully weighs several individual patient factors:

• Statin Intensity: Choosing low, moderate, or high-intensity therapy based on the patient's starting risk factors and target LDL/ApoB reduction.
• Metabolic Effects: Certain statins may slightly increase blood sugar levels. A patient's history of diabetes, prediabetes, or other metabolic risk factors may influence statin selection and monitoring.
• Personal Tolerance: Finding a medication that does not cause unwanted side effects like muscle aches. Certain people may be at higher risk of side effects than others.
• Drug Interactions: Ensuring the statin does not interfere with other daily medicines a patient takes.
• Overall Fit: The ideal statin is one that safely achieves cholesterol-lowering goals while fitting a patient's individual needs, including their other medications, side effect history, and blood sugar considerations.

The right statin is simply the one that can safely achieve your target cholesterol reduction and fits your daily routine.

Certain statins may offer additional advantages for specific patients. For example, Zypitamag (pitavastatin) may be considered when minimizing drug interactions or limiting effects on blood sugar is an important treatment consideration.

Does Lowering Cholesterol Prevent Heart Attacks?

Overall, researchers have found that if you lower the right target lowering cholesterol does prevent heart attacks.

Preventing heart events depends on:

• Which particle is lowered: Lowering ApoB-containing particles (like LDL) lowers risk, but raising HDL alone does not.
• How much it is lowered: Larger reductions in ApoB-containing particle counts leads to larger reductions in risk.
• How long it is sustained: Keeping particle counts low over many years produces the greatest protection.

Researchers still continue to study these findings to improve our understanding but currently the large amount of trial data supports this information.

How to Read the Next Headline About a Cholesterol Drug

When you see news reports about new heart medications, use this 3-step checklist to get a better idea of the story:

1. What did the medication change? Did the drug lower ApoB-containing particles, or did it simply raise HDL?
2. By how much? Did it create a major, lasting reduction in harmful particles?
3. Did the trial count events? Did the study prove a reduction in MACE (heart attacks and strokes), or did it only report blood test numbers?

What This Means for Your Health Today

If you currently take a cholesterol-lowering medication, the history of these clinical trials doesn't change anything about your daily routine.

Standard, approved medications including statins, ezetimibe, and other established heart health medications remain the proven way to protect your heart today.

For more details on managing your current regimen, explore our guide on how to choose a statin.

Never stop or change a prescribed heart medication based on news articles you read online. If you have questions about your cholesterol numbers or your current prescription, schedule a conversation with your healthcare provider.

Questions? Talk to a Marley Drug Pharmacist

Understanding heart health trials can feel complex. The pharmacy team at Marley Drug is always available to help you with any questions or to aid you with your medications.

You can speak with a licensed pharmacist free of charge by calling 800-286-6781.

Disclaimer
This article is for educational purposes only and does not replace professional medical advice, diagnosis, or treatment. Always consult your healthcare provider or pharmacist regarding any specific health concerns or before starting, stopping, or changing any prescription drug.

All information is current as of November 2026.

References

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3. Lincoff AM, Nicholls SJ, Riesmeyer JS, et al. Evacetrapib and Cardiovascular Outcomes in High-Risk Vascular Disease (ACCELERATE Trial). N Engl J Med. 2017;376(20):1933-1942.
4. HPS3/TIMI55-REVEAL Collaborative Group. Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease (REVEAL Trial). N Engl J Med. 2017;377(13):1217-1227.
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7. European Medicines Agency (EMA). Ubeslo (obicetrapib) & Evlarco (obicetrapib/ezetimibe) European Public Assessment Report (EPAR). Published September 21, 2026. Accessed November 3, 2026.
8. National Institutes of Health (NIH). A Study of Obicetrapib in Patients With Cardiovascular Disease (PREVAIL). ClinicalTrials.gov. Identifier: NCT05202509. Accessed November 3, 2026.
9. Bhatt DL, Steg PG, Miller M, et al. Cardiovascular Risk Reduction with Icosapent Ethyl for Hypertriglyceridemia (REDUCE-IT Trial). N Engl J Med. 2019;380(1):11-22.
10. Nidorf SM, Fiolet ATL, Mosterd A, et al. Colchicine in Patients with Chronic Coronary Disease (LoDoCo2 Trial). N Engl J Med. 2020;383(19):1838-1847.