Intellia Therapeutics has unveiled highly positive and durable three-year follow-up data from the Phase 1 portion of its ongoing study of lonvoguran ziclumeran (lonvo-z), a groundbreaking one-time CRISPR-based gene editing therapy for hereditary angioedema (HAE). Presented at the European Academy of Allergy and Clinical Immunology (EAACI) Congress 2025 in Glasgow, UK, the results demonstrated that a single intravenous dose of lonvo-z was exceptionally well-tolerated and achieved a 98% mean reduction in monthly HAE attack rates compared to baseline. Critically, all 10 patients in the Phase 1 cohort remained attack-free and off chronic therapy for a median of nearly two years, showcasing deep, dose-dependent, and sustained reductions in plasma kallikrein protein. The safety profile remained favorable, with the most frequent adverse events being mild (Grade 1) infusion-related reactions, and notably, no treatment-emergent serious adverse events observed for up to three years. These compelling data significantly bolster Intellia's confidence in their gene-editing approach, fueling optimism for the ongoing global Phase 3 HAELO trial, which has already successfully completed patient screening ahead of schedule and is no longer recruiting, with a Biologics License Application (BLA) submission for a potential U.S. launch anticipated in 2026 for 2027 launch. Lonvo-z is designed to inactivate the KLKB1 gene, which encodes for prekallikrein, thereby preventing HAE attacks.