Clinical Report: In Vivo CRISPR Therapy Succeeds in Phase 3 Trial

Overview

A phase 3 trial demonstrated that a one-time in vivo CRISPR therapy reduced attacks in patients with hereditary angioedema. The treatment, lonvoguran ziclumeran, showed an 87% relative reduction in attack rates compared to placebo.

Background

Hereditary angioedema is a rare genetic disorder characterized by recurrent swelling attacks. Current treatment options often require continuous prophylaxis. The introduction of CRISPR gene editing therapy represents a new approach in the management of this condition.

Data Highlights

Key Findings

• The trial enrolled 80 patients aged 16 years or older with hereditary angioedema due to C1 inhibitor deficiency.
• Lonvoguran ziclumeran reduced attacks requiring on-demand treatment by 89% compared to placebo.
• Moderate-to-severe attacks fell by 91% in the lonvo-z group.
• 62% of patients receiving lonvo-z were attack-free between weeks 5 and 28 without long-term prophylaxis.
• Adverse events were reported in 92% of patients receiving lonvo-z, with no serious or grade 3 or higher events noted.

Clinical Implications

The findings indicate that a single-dose CRISPR therapy could reduce the need for continuous prophylactic treatment in patients with hereditary angioedema.

Conclusion

The phase 3 trial results indicate that in vivo CRISPR therapy is effective and well-tolerated.

Related Resources & Content

1. Intellia Therapeutics, New England Journal of Medicine, 2023 -- CRISPR-Cas9 In Vivo Gene Editing of KLKB1 for Hereditary Angioedema
2. the medicine maker, This Week’s CGT News: CRISPR Hits Phase 3 Milestone, 2026 -- CRISPR gene editing shows Phase 3 success in hereditary angioedema
3. the medicine maker, CRISPR Enables In Vivo CAR T Cell Production, 2026 -- A new CRISPR-based approach could eliminate one of the biggest bottlenecks in cell therapy.
4. the medicine maker, T-knife Launches Phase 1 Trial of CRISPR T Cell Therapy, 2026 -- T-knife Therapeutics has received authorization to begin a Phase 1 clinical trial.
5. UCL Discovery, 2025 WAO Guidelines for the classification, diagnosis, and treatment of hereditary angioedema, 2025 -- Current guideline framework and standard of care.
6. the asco post — CRISPR-Cas9-Edited TILs: Targeting Intracellular Immune Checkpoint CISH in Metastatic Colorectal Cancer
7. The 2025 WAO Guidelines for the classification, diagnosis, and treatment of hereditary angioedema, with consideration of worldwide disparities - UCL Discovery
8. CRISPR-Cas9 In Vivo Gene Editing of KLKB1 for Hereditary Angioedema | New England Journal of Medicine