Zug, Switzerland & Boston, Mass. – August 28, 2026

CRISPR Therapeutics presented new Phase 1a durability data for CTX310, an investigational in vivo CRISPR/Cas9 gene-editing therapy targeting ANGPTL3, at the European Society of Cardiology (ESC) Congress 2026. The company reported that a single intravenous infusion produced sustained reductions in circulating ANGPTL3, triglycerides (TG) and LDL cholesterol through one year of follow-up. At the highest evaluated dose of 0.8 mg/kg, mean reductions from baseline reached 79% for ANGPTL3, 48% for triglycerides and 53% for LDL, with maximum reductions of 89%, 78% and 84%, respectively. The findings were also published in The New England Journal of Medicine. For cGxP.wire, the key development is the one-year durability of the CTX310 gene-editing effect after a single infusion, supporting continued clinical development of an in vivo approach for lipid disorders where conventional therapies require long-term treatment.

CRISPR Therapeutics Demonstrates One-Year CTX310 Durability

The latest CTX310 Phase 1a data extend the company’s earlier clinical findings by showing that ANGPTL3 editing and associated lipid reductions remained evident after one year. The open-label, dose-escalation study evaluated a single IV administration of CTX310 across participants with familial hypercholesterolemia, severe hypertriglyceridemia and mixed dyslipidemias who had elevated lipid levels despite standard-of-care treatment. Among participants receiving the highest 0.8 mg/kg dose, the mean reduction in circulating ANGPTL3 was 79% at one year, while triglycerides declined by an average of 48% and LDL by 53%. Maximum individual reductions reached 89% for ANGPTL3, 78% for triglycerides and 84% for LDL. The persistence of these effects is particularly relevant to the program because CTX310 is designed as a one-time gene-editing treatment, potentially offering sustained biological activity without the repeated dosing required by many existing lipid-lowering therapies.

CTX310 Safety Profile Remains Consistent During Follow-Up

The extended follow-up also provided additional information on the safety and tolerability of CTX310. Fifteen participants received single-course ascending doses and all had completed at least one year of follow-up at the data cutoff. According to CRISPR Therapeutics, there were no treatment-related serious adverse events, no dose-limiting toxicities and no new treatment-related safety events during the extended follow-up period. Previously reported events included one allergic reaction that resolved with supportive care and three Grade 2 infusion-related reactions. A transient aminotransferase elevation had also previously been observed in one participant shortly after treatment, but no continuing liver-function abnormalities were reported during the remainder of follow-up. These findings provide an early safety picture for CTX310, although the Phase 1a study involved only 15 participants, making larger and longer studies necessary to characterize the safety profile of in vivo gene editing more fully.

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CRISPR Therapeutics Advances CTX310 Into Phase 1b

CRISPR Therapeutics is continuing development of CTX310 in a Phase 1b clinical trial, using a fixed flat-dose regimen equivalent to the most efficacious Phase 1a dose of 0.8 mg/kg. The company expects to provide another program update in the second half of 2026, with upcoming data focused on patients with severe hypertriglyceridemia. CTX310 is part of CRISPR Therapeutics’ broader cardiovascular gene-editing portfolio, which also includes CTX340, targeting angiotensinogen for refractory hypertension, and CTX321, targeting LPA for elevated lipoprotein(a). The latest results do not establish clinical cardiovascular-outcome benefit and remain based on an early-stage, small Phase 1 population. However, the durable one-year ANGPTL3 editing and lipid lowering after a single infusion provide an important clinical proof-of-concept for the company’s strategy of developing potentially long-lasting in vivo gene-editing therapies for cardiometabolic disease.

Source: CRISPR Therapeutics, press relese