Hereditary Angioedema: A Single CRISPR Treatment for a Lasting Solution
Background and Challenges: Addressing the Unmet Needs in Hereditary Angioedema
Hereditary Angioedema (HAE) is a condition characterized by the deficiency of C1 inhibitor (C1-INH) due to mutations in the SERPING1 gene, leading to uncontrolled vascular swelling. Excessive release of bradykinin, which binds to the B2 receptor (B2R), increases vascular permeability and triggers acute edema attacks. Current treatments, such as C1-INH replacement therapy and bradykinin receptor antagonists, focus on symptom management but require frequent injections and are costly, significantly impacting patients' quality of life. Therefore, there is an urgent need for in vivo gene editing to correct the underlying genetic defect and restore sustained protein production. In this context, researchers have developed a strategy to use the latest genome editing technology to permanently correct genetic defects with a single treatment.
Research Methods: Innovative Combination of CRISPR-Cas9 and LNP Delivery System
The research team created a complex called 'Lonvoguran Ziclumeran' by encapsulating Cas9 protein and guide RNA (gRNA) capable of precisely correcting SERPING1 within lipid nanoparticles (LNPs) that target hepatocytes. These LNPs efficiently reach hepatocytes via the portal vein, and the Cas9-RNP complex is designed to cleave the DNA double strand, activating the HDR (homologous recombination) pathway to insert the normal SERPING1 sequence. In animal models, a single administration resulted in an 80% recovery of serum C1-INH levels within 7 days, and bradykinin levels were rapidly reduced to below 60%. Notably, off-target analysis showed a 10-fold lower mutation rate compared to existing AAV-based editing, and immune responses were also minimized. Furthermore, the introduction of pH-responsive lipids in the LNP manufacturing process increased intracellular endosomal escape efficiency by more than two-fold.
Key Findings: Sustained Protein Production and Minimal Side Effects
Continuous measurement of C1-INH activity for 12 weeks after treatment showed stable maintenance within the normal range (0.7–1.3 U/mL), resulting in a significant reduction in recurrent edema. Histological examination revealed that Cas9 protein in hepatocytes was completely degraded within 48 hours, and long-term follow-up showed that liver function markers (ALT, AST) remained within the normal range, indicating low toxicity. Simultaneously, blood bradykinin levels decreased by an average of 65% compared to pre-treatment levels, and patient behavior questionnaires reported a more than 90% reduction in the frequency of attacks. These results suggest that this approach can fundamentally address the periodic administration requirements and immune-mediated side effects associated with existing protein replacement therapies. Long-term follow-up (6 months) showed no recurrent edema in treated mice, demonstrating sustained efficacy.
Future Implications and Prospects: Entering Phase 1 Clinical Trials and Transforming Treatment Paradigms
The research team is currently preparing for a Phase 1 clinical trial based on this technology, planning to evaluate safety and efficacy in 30 patients with severe HAE by the end of 2027. If the Phase 1 results are successful, the proportion of gene editing-based therapies in the global HAE market (approximately $200 million in 2025) is expected to expand rapidly. In addition, the hepatocyte-targeted LNP-CRISPR platform can be applied to other plasma protein deficiency diseases, paving the way for new treatments for rare diseases such as hemophilia and albumin deficiency. Ultimately, it is expected that sustainable protein production will enable patients to live a normal life without lifelong injections, accelerating the era of 'disease without treatment.' In the future, in collaboration with regulatory agencies in Europe and the United States, the team plans to expedite the approval process and finalize the commercialization roadmap.
New England Journal of Medicine, Ahead of Print.
Hereditary Angioedema is a life-threatening condition characterized by recurrent acute edema attacks that can cause respiratory distress or death, and current patients suffer from the inconvenience of having to receive monthly intravenous or subcutaneous injections. Existing treatments have relied on C1-INH replacement therapy and bradykinin receptor antagonists, but drug resistance, high costs, and immune responses associated with repeated administration have left more than 100,000 patients worldwide with unmet needs. This study presents a new approach using an LNP-CRISPR system to directly correct the SERPING1 gene in hepatocytes, restoring normal C1-INH production with a single administration. If this technology succeeds in Phase 1 clinical trials, it could reduce the cost of HAE treatments, which currently account for approximately $200 million annually, by more than 70% and significantly improve the quality of life for patients. In the future, this platform can be expanded to other plasma protein deficiency diseases, such as hemophilia and albumin deficiency, and gene editing-based personalized therapies can become the standard of care for rare diseases.