One injection. Twelve months later, the effect was still holding.
That's the headline finding from a small but closely watched trial at Cleveland Clinic. In the trial, a single dose of an experimental gene-editing therapy cut "bad" cholesterol and triglycerides by roughly half, and kept them there for a year.
The results were presented at the European Society of Cardiology's ESC Congress 2026 and published simultaneously in the New England Journal of Medicine. They build on earlier two-month data that the team first reported in November 2025.
What the treatment actually does
The therapy, called CTX310, uses CRISPR-Cas9 gene-editing technology to make a targeted, lasting change to DNA inside liver cells. It is given as a single infusion that carries the editing system to the liver, where it switches off a gene called ANGPTL3.
ANGPTL3 normally helps regulate fats circulating in the blood. Disabling it can reduce two of them. One is LDL cholesterol, the "bad" cholesterol linked to clogged arteries and heart disease. The other is triglycerides, another blood fat associated with cardiovascular risk.
Statins and similar medications need to be taken every day to keep working. The idea behind CTX310 is different: a single dose could produce a lasting effect, because the gene itself is edited rather than its activity being blocked temporarily.
The numbers
The Phase 1 trial involved just 15 participants. All of them had lipid disorders that had not responded adequately to existing medication. Each received one of several doses of CTX310, ranging from 0.1 to 0.8 mg/kg. Beforehand, they were given corticosteroids and antihistamines to reduce infusion reactions.
Twelve months after treatment, patients in the highest-dose group had LDL cholesterol levels an average of 52.5% lower than when they started. Their triglycerides were 47.8% lower. No serious adverse events related to the therapy were reported during that year of follow-up.
"Building upon the initial data presented in November 2025, the durability of the lipid-lowering effect was impressive," said Dr Luke Laffin, a Cleveland Clinic cardiologist and the study's first author. "It is encouraging that there were no serious safety events related to CTX310 in the trial and in the year following treatment. We look forward to continuing to investigate this therapy in a larger number of patients."
Why the caution matters
It's worth being clear-eyed about what this is, and what it isn't. This is a Phase 1 trial, the earliest stage of human testing. It is designed primarily to check safety, not to prove that a treatment works at scale. Fifteen patients is a small group, and the headline results come from the highest dose tested.
Researchers plan to continue monitoring participants' safety for another 15 years, in line with US Food and Drug Administration recommendations for gene-editing therapies. Larger trials will be needed before CTX310 could become an approved treatment.
The study was funded by CRISPR Therapeutics AG, the Swiss biotech company developing the therapy. Dr Laffin's institution has received research funding from the company.
What this means if you're worried about your cholesterol
If you have high cholesterol or triglycerides, this trial isn't a reason to change anything about your treatment today. CTX310 remains experimental. It is years away from being available, if it clears further trials at all.
The sensible approach, as ever, is to keep taking any cholesterol-lowering medication your GP has prescribed. If you have questions about new treatments, including gene-editing therapies like this one, raise them at your next appointment. Don't stop existing treatment on the strength of a headline.
Sources: Cleveland Clinic; Laffin LJ et al., New England Journal of Medicine, 2026 (DOI: 10.1056/NEJMc2609825); ESC Congress 2026.
