A single infusion of an experimental gene-editing treatment kept “bad” cholesterol and another blood fat about half as high one year later, in a small early trial of people whose levels stayed high despite medicines1. At the highest dose, LDL cholesterol was 52.5% below where it started after 12 months, and triglycerides, another fat in the blood, were 47.8% lower1. No serious side effects related to the treatment were reported during the year1.
The one-year results were presented at the 2026 European Society of Cardiology annual meeting and published at the same time in the New England Journal of Medicine1. Days later, Oregon Health & Science University (OHSU) said it had enrolled the first person on the US West Coast in a multicenter trial of the same treatment2.
What happened
The treatment, called CTX310, is given once, as an infusion into the blood1. It uses CRISPR-Cas9, a gene-editing tool designed to make targeted changes to specific parts of a person’s DNA1. In this trial, researchers followed 15 patients for a year to see whether the drops in cholesterol and triglycerides first reported after two months would last1.
“Building upon the initial data presented in November 2025, the durability of the lipid-lowering effect was impressive,” said Cleveland Clinic cardiologist Luke Laffin, the study’s first author1. He added that the team looks forward to studying the therapy “in a larger number of patients”1.
How the treatment works
The infusion carries the editing tool to the liver, where it switches off a gene called ANGPTL31. That gene helps regulate fats circulating in the blood, and disabling it can reduce LDL cholesterol and triglycerides, both of which are linked to heart and blood vessel disease1.
OHSU’s site investigator, cardiologist Ahmad Masri, described the gene as a brake. “All of us have this gene,” he said. “Its job is to essentially act as a brake system to slow the clearing of cholesterol, which is useful in an evolutionary standpoint to combat starvation.”2 The editing tool is packed into tiny fat particles, called lipid nanoparticles, that deliver it to the liver2.
The idea comes from people born with a natural change in this gene. They have lifelong low cholesterol and triglycerides, a lower lifetime risk of heart disease and no apparent harmful effects, the researchers said in 20253. Steven Nissen of Cleveland Clinic, who oversaw the study with Laffin, called this “a natural experiment in what would happen if we actually changed the gene”4.
The evidence so far
This was a first-in-human Phase 1 trial, the earliest stage of testing in people, mainly meant to check safety1. Patients received doses from 0.1 to 0.8 mg per kilogram of body weight, after first being given steroids and antihistamines1. Researchers then tracked safety and measured changes in the ANGPTL3 protein, LDL cholesterol and triglycerides1.
The trial ran from June 2024 to August 2025 at six sites in Australia, New Zealand and the United Kingdom, in adults aged 31 to 68 with uncontrolled high triglycerides and raised LDL cholesterol3. Earlier results, presented in November 2025 at the American Heart Association meeting, showed LDL down by about 50% and triglycerides down by about 55%3. Within two weeks, people on the highest dose saw both levels drop by half, the Associated Press reported4.
The new data show those effects held at one year: on average, about a 50% drop in both LDL and triglycerides at the top dose1. In the earlier report, three participants had minor reactions, including back pain and nausea, that went away with medication3.
What it does not show yet
The study involved only 15 people, and the treatment remains experimental1. The headline numbers come from the highest-dose group, not from everyone in the trial1. The trial measured blood fat levels; it did not measure heart attacks, strokes or deaths, which would need much larger and longer studies.
Long-term safety is the biggest open question. Patients will be followed for another 15 years, in line with US Food and Drug Administration recommendations for gene-editing therapies1. Joseph Wu of Stanford University, who was not involved, told the Associated Press that CRISPR-based therapies have not been used enough to know their long-term safety, that the particles carrying the tool can irritate or inflame the liver, and that it is not yet known whether editing hits only the intended target4. That is why, for now, studies largely enroll people at very high risk4.
Gene editing is considered permanent: if edited liver cells divide, the new cells carry the altered gene too4. That is part of the appeal, but it also means a treatment cannot simply be stopped the way a pill can.
Who is behind it
CTX310 is developed by CRISPR Therapeutics, based in Zug, Switzerland, which funded the study1. Laffin’s institution has received research funding from the company1. The company also sponsors the new multicenter trial2. The NEJM paper lists authors from several institutions, with Nissen as the last author1.
The researchers frame the treatment around a practical problem. “We know that up to 50% of people by a year after their statin prescription stop taking it,” Laffin said in 20253. Nissen added that because high cholesterol has no symptoms, people tire of daily medicines3.
How it fits the field
CRISPR Therapeutics is not alone. Verve Therapeutics, a Boston company that is now part of Eli Lilly, has tested a gene-editing infusion that targets a different liver gene, PCSK9, and reported a similar cut in LDL cholesterol in a small study4. Verve’s first trial, in 10 people with an inherited form of very high cholesterol, reported LDL falling to about half at the higher dose. It also reported two severe heart events in patients with advanced heart disease, one of them a death from cardiac arrest about five weeks after treatment5.
There are already injected medicines that block the proteins made by the PCSK9 and ANGPTL3 genes in the liver4. The difference with gene editing is the aim of a one-time treatment instead of repeated doses. “Rather than a once-daily pill or monthly injection, this therapy would potentially offer a one-time infusion,” Laffin said in 20253.
The approach was tested first in animals. In a 2021 mouse study at Tufts University, a single shot of a CRISPR treatment aimed at the same gene lowered LDL by up to 56.8% and triglycerides by 29.4%, with effects that stayed stable for 100 days6. Those results were in mice only.
What to watch next
The treatment is now moving into more patients and into the United States. OHSU is the only West Coast center in a multicenter trial that is testing CTX310 at 17 centers worldwide, and it is focused on safety2. It is enrolling adults aged 18 to 75 who cannot control their LDL cholesterol or triglycerides with existing medicines such as statins2. OHSU’s first participant is a 54-year-old woman whose LDL is so high that she has her blood filtered every week to remove cholesterol, a treatment called apheresis2.
“Initially, it would be most useful for patients who can’t tolerate statins or other alternative medications, or they’re on those medications and still have high cholesterol,” Masri said2. In 2025, the Cleveland Clinic team said it hoped to begin Phase 2 studies in 2026 and reach Phase 3, the last big stage before approval, within two to three years3.
The next things to look for are results from more patients, whether the cholesterol drop lasts beyond one year, and what longer follow-up shows about liver safety and unintended edits.
