Two new injectable medications called olezarsen and plozasiran significantly lower triglycerides—a dangerous type of blood fat—by blocking a liver protein called apoC-III. According to Gram Research analysis of clinical trials, both drugs produced substantial triglyceride reductions in patients with familial chylomicronemia syndrome and other forms of severe high triglycerides. While they appear safe overall, doctors must monitor liver function and blood sugar levels during treatment.
Two new medications called olezarsen and plozasiran have been approved to help people with dangerously high triglycerides—a type of fat in the blood that can cause serious health problems. According to Gram Research analysis, these drugs work by reducing a protein called apoC-III that your liver makes, which helps your body clear triglycerides more efficiently. In clinical trials, both medications significantly lowered triglyceride levels in patients with familial chylomicronemia syndrome and other forms of high triglycerides. While they appear safe overall, doctors need to monitor liver function and blood sugar levels in patients taking these drugs.
Key Statistics
A 2026 review of randomized controlled trials found that both olezarsen and plozasiran significantly reduced triglyceride levels in adults with familial chylomicronemia syndrome by blocking apoC-III production in the liver.
According to clinical trial data reviewed in 2026, both olezarsen and plozasiran improved multiple blood fat measurements beyond just triglycerides, suggesting potential benefits for overall heart health.
A 2026 review of safety data from multiple trials found that olezarsen and plozasiran were generally well tolerated, though monitoring of liver enzymes, blood sugar, and platelet counts is warranted during treatment.
The Quick Take
- What they studied: How well two new medications (olezarsen and plozasiran) lower triglycerides—a dangerous type of fat in the blood—and whether they’re safe to use
- Who participated: Adults with familial chylomicronemia syndrome and other forms of high triglycerides who participated in randomized controlled trials comparing these drugs to placebo (fake treatment)
- Key finding: Both medications significantly reduced triglyceride levels by blocking a liver protein called apoC-III, helping the body clear triglycerides more effectively
- What it means for you: If you have dangerously high triglycerides that don’t respond to diet and exercise, these new drugs offer a promising treatment option, though your doctor will need to monitor your liver and blood sugar regularly
The Research Details
This is a review article that summarizes findings from multiple randomized controlled trials—the gold standard type of medical research. In these trials, some patients received olezarsen or plozasiran while others received a placebo (inactive treatment), and researchers compared how well each drug worked. The trials included patients with different levels of triglyceride problems, from the most severe form (familial chylomicronemia syndrome, where the body can’t clear triglycerides at all) to milder cases. By reviewing all these trials together, researchers could see patterns in how well the drugs worked and what side effects occurred.
The medications work by targeting a specific protein called apoC-III that your liver produces. This protein normally slows down how quickly your body removes triglycerides from the blood. By blocking the production of this protein, the drugs help your body clear triglycerides much more efficiently. This is a completely different approach from older triglyceride medications, which is why these drugs are considered novel or new.
The review examined both the effectiveness of these drugs (how much they lowered triglycerides) and their safety profile (what side effects patients experienced). Researchers looked at how the drugs affected not just triglycerides, but also other blood fats and cholesterol levels that matter for heart health.
High triglycerides are a serious health problem that many people don’t realize they have. When triglycerides get extremely high (above 1,000 mg/dL), they can cause acute pancreatitis, a painful and potentially life-threatening inflammation of the pancreas. Even moderately high triglycerides increase your risk of heart disease and stroke. Current treatments—diet changes, exercise, and older medications—don’t work well enough for everyone, especially people with genetic forms of high triglycerides. These new drugs offer hope for patients who haven’t responded to existing treatments.
This is a review article published in a peer-reviewed medical journal, which means experts in cardiology and lipid disorders evaluated it before publication. The strength of the conclusions depends on the quality of the underlying clinical trials being reviewed. The authors acknowledge that more research is needed to prove these drugs actually prevent heart attacks, strokes, and pancreatitis—they’ve only shown they lower triglycerides. The fact that the review was published in 2026 means it includes the most recent clinical trial data available.
What the Results Show
Both olezarsen and plozasiran produced significant reductions in triglyceride levels in patients with high triglycerides. The drugs work by reducing apoC-III, a protein that normally prevents your body from clearing triglycerides efficiently. When apoC-III levels drop, your body can remove triglycerides from the blood much more effectively.
Beyond just lowering triglycerides, both drugs also improved other important blood fat measurements. This is important because heart disease risk depends on multiple factors, not just triglyceride levels alone. The improvements in these other lipid measurements suggest the drugs might help protect heart health in multiple ways.
The medications appeared to be generally well tolerated, meaning most patients didn’t experience serious side effects. However, some monitoring is necessary. Doctors need to check liver enzymes regularly because the liver is where these drugs work, and they need to monitor blood sugar levels because the drugs can affect how your body handles glucose.
For olezarsen specifically, doctors also need to monitor platelet counts (blood cells that help with clotting) because this drug may affect platelet levels. The review notes that both drugs showed promise in patients with familial chylomicronemia syndrome, the most severe form of high triglycerides where the body almost completely fails to clear triglycerides on its own. This is particularly important because patients with this genetic condition have very few treatment options.
These drugs represent a major advance in triglyceride treatment. Older medications like fibrates and niacin work through different mechanisms and don’t work as well for everyone. The new drugs target a specific biological problem (apoC-III overproduction) that was identified through genetic research. This targeted approach is more precise and appears more effective than older, broader-acting medications. However, unlike some older medications, these new drugs are injections rather than pills, which requires more frequent doctor visits.
The biggest limitation is that these trials only measured whether the drugs lower triglycerides—they didn’t prove the drugs actually prevent heart attacks, strokes, or pancreatitis. Lowering triglycerides is important, but the ultimate goal is preventing these serious health events. The review authors specifically note that future trials are needed to prove clinical benefit. Additionally, because these are new drugs, long-term safety data (beyond the trial periods) isn’t yet available. The trials also primarily included patients with familial chylomicronemia syndrome, so we know less about how well these drugs work in people with other causes of high triglycerides.
The Bottom Line
For patients with familial chylomicronemia syndrome or severe high triglycerides that don’t respond to diet, exercise, and other medications: These drugs represent a promising new treatment option with strong evidence of triglyceride reduction (high confidence). For patients with mild to moderate high triglycerides: These drugs should be considered only after trying diet, exercise, and established medications first, as they’re newer and more expensive (moderate confidence). All patients taking these drugs need regular monitoring of liver function and blood sugar (high confidence).
Patients with familial chylomicronemia syndrome should definitely discuss these drugs with their cardiologist or lipid specialist. People with very high triglycerides (above 500 mg/dL) that haven’t improved with diet and exercise should ask their doctor about these options. People with normal or only slightly elevated triglycerides don’t need these drugs. Patients with liver disease should be cautious and discuss risks carefully with their doctor.
Triglyceride levels typically begin dropping within weeks of starting these medications, with maximum effect usually seen within a few months. However, you won’t immediately feel better because high triglycerides usually don’t cause symptoms. The real benefit—preventing heart disease and pancreatitis—would take years to measure and hasn’t yet been proven in clinical trials.
Frequently Asked Questions
What are olezarsen and plozasiran used for?
These injectable medications treat dangerously high triglycerides, especially in people with familial chylomicronemia syndrome where the body can’t clear triglycerides normally. They work by blocking a liver protein called apoC-III, helping your body remove triglycerides from the blood more efficiently.
How much do these drugs lower triglycerides?
Clinical trials show both drugs produce significant triglyceride reductions, though exact percentages vary by patient. They also improve other blood fat measurements important for heart health. The drugs work best in people with the most severe forms of high triglycerides.
Are olezarsen and plozasiran safe?
Both drugs appear generally well tolerated based on clinical trials, but they require regular monitoring. Doctors must check liver enzymes and blood sugar levels regularly. Olezarsen also requires monitoring of platelet counts. Long-term safety data beyond trial periods isn’t yet available.
Will these drugs prevent heart attacks and pancreatitis?
These drugs effectively lower triglycerides, which is important for preventing these conditions. However, clinical trials haven’t yet proven they actually prevent heart attacks, strokes, or pancreatitis. Future research is needed to confirm these clinical benefits.
Who should take olezarsen or plozasiran?
Patients with familial chylomicronemia syndrome or severe high triglycerides unresponsive to diet and other medications are the primary candidates. These are injectable drugs requiring regular doctor visits, so they’re typically reserved for people who haven’t responded to other treatments.
Want to Apply This Research?
- Track your triglyceride levels every 3 months (or as recommended by your doctor) and log them in the app with the date and your current medication. Create a reminder for your regular liver enzyme blood tests and blood sugar checks, which are essential monitoring for these drugs.
- Set reminders for your injection schedule (these are injectable medications, not pills). Log any side effects or unusual symptoms you notice, and track your diet and exercise habits alongside your triglyceride measurements to see how lifestyle changes combine with medication effects.
- Create a dashboard showing your triglyceride trend over time, with target ranges marked. Set alerts for upcoming blood work appointments. Track liver enzyme results and fasting blood sugar levels in a separate section to monitor for potential side effects. Share this data with your doctor at each visit.
This article reviews clinical research on olezarsen and plozasiran but is not medical advice. These medications are prescription drugs that require doctor supervision. If you have high triglycerides or familial chylomicronemia syndrome, discuss these treatment options with your cardiologist or lipid specialist. Do not start, stop, or change any medication without consulting your healthcare provider. While these drugs show promise in lowering triglycerides, clinical trials have not yet proven they prevent heart attacks, strokes, or pancreatitis. Individual results vary, and these drugs may not be appropriate for everyone.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.