Intellia Therapeutics Reports Promising Three-Year Data for Lonvo-z in HAE Treatment

Intellia Therapeutics, Inc. (NASDAQ: NTLA), a pioneering gene editing company, announced on June 15, 2025, during the European Academy of Allergy and Clinical Immunology (EAACI) Congress in Glasgow, promising three-year follow-up data regarding the effectiveness of lonvoguran ziclumeran (lonvo-z) for the treatment of hereditary angioedema (HAE). The Phase 1 trial results indicated that a single dose of lonvo-z led to a remarkable 98% mean reduction in the monthly HAE attack rate across all ten patients involved in the study, with a median follow-up period of 23 months during which all patients remained attack-free and treatment-free.

Dr. John Leonard, President and CEO of Intellia, emphasized the significance of the results, stating, "Today’s results underscore the promising potential of Intellia’s approach to gene editing therapy – a one-time treatment that was well tolerated and offered a highly differentiated, durable effect for patients suffering from a serious disease.” This data not only illustrates the efficacy of lonvo-z but also reinforces the company’s commitment to addressing critical unmet medical needs.

In the clinical trial, a one-time intravenous dose was administered at varying levels (25 mg, 50 mg, and 75 mg) to patients, with subsequent measurements of plasma kallikrein protein levels and HAE attack frequency. The study demonstrated deep, dose-dependent, and durable reductions in plasma kallikrein protein levels, which are involved in the pathology of HAE. Notably, no serious adverse events were reported throughout the study, and the treatment exhibited a safety profile consistent with previous findings.

Dr. Joshua Jacobs, Medical Director at Allergy and Asthma Clinical Research, remarked on the implications of the treatment for patient quality of life, noting, "People living with HAE often report a reduced quality of life because they worry about the likelihood of their next attack... Based on the data, it is reasonable to expect lonvo-z could offer patients the potential to be free from both physical HAE attacks and the burden of managing chronic HAE treatment.”

The HAELO trial, Intellia’s global Phase 3 study assessing the safety and efficacy of lonvo-z, has also recently completed screening ahead of schedule, with over half of the participants screened from United States sites. Intellia anticipates providing updates on enrollment as the study progresses. Furthermore, the company plans to submit a biologics license application (BLA) in 2026, aiming for a potential U.S. market launch in 2027.

Lonvo-z, based on CRISPR/Cas9 technology, represents a significant advancement in the treatment of hereditary angioedema, potentially becoming the first one-time therapy for the condition. The investigational therapy works by inactivating the kallikrein B1 (KLKB1) gene, which plays a critical role in HAE attack mechanisms. Intellia has received five notable regulatory designations for lonvo-z, including Orphan Drug and Regenerative Medicine Advanced Therapy (RMAT) Designations from the FDA, underscoring its potential as a groundbreaking treatment.

As the field of gene editing continues to evolve, the results from Intellia’s ongoing studies may pave the way for new therapeutic avenues for patients suffering from hereditary angioedema and potentially other genetic disorders, showcasing the transformative power of CRISPR-based therapies in modern medicine.