Intellia Therapeutics Presents Positive Pooled Phase 1/2 Data of Lonvoguran Ziclumeran (lonvo-z) in Patients with Hereditary Angioedema

Deep, stable and durable reductions in kallikrein observed Among 32 patients who received a 50 mg dose of lonvo-z as of data cutoff:

31 (97%) were attack-free and long-term prophylaxis (LTP)-free 24 (75%) were attack-free and LTP-free for at least seven months (up to 32 months)Among the 11 patients who originally received a 50 mg dose in Phase 2, 10 were attack-free and LTP-free Continue to observe a well-tolerated safety profile with up to three years of patient follow-up and no new long-term risks identified

CAMBRIDGE, Mass., Nov. 08, 2025 (GLOBE NEWSWIRE) -- Intellia Therapeutics, Inc. (NASDAQ: NTLA), a leading clinical-stage gene editing company focused on revolutionizing medicine with CRISPR-based therapies, today presented positive clinical data from a pooled analysis of all patients who received a 50 milligram (mg) dose of lonvo-z in the company’s ongoing Phase 1/2 clinical trial in patients with hereditary angioedema (HAE). These results were shared in an oral presentation today at the American College of Allergy, Asthma & Immunology (ACAAI) 2025 Annual Scientific Meeting in Orlando, Florida.

“Today’s data further support our belief that lonvo-z could completely redefine the HAE treatment landscape,” said Intellia President and Chief Executive Officer John Leonard, M.D. “With up to three years of follow-up, the vast majority of patients who received a one-time 50 mg dose of lonvo-z – including 10 of our original 11 patients who received this dose in Phase 2 – were both attack-free and LTP-free as of the data cutoff. We are looking forward to our approaching topline readout from our Phase 3 HAELO clinical trial by mid-2026.”

“Hereditary angioedema is a condition with significant burden that is marked by the unpredictable nature of when the next attack could occur, the painful and often prolonged swellings themselves as well as the need for lifelong treatment,” said Dr. Danny Cohn, M.D., Ph.D., Internist, Department of Vascular Medicine, Amsterdam University Medical Center. “The data presented today offer hope that lonvo-z could significantly reduce or remove those burdens for many patients via a one-time treatment. I am eagerly awaiting results from the ongoing HAELO Phase 3 clinical trial.”

Pooled Phase 1/2 Analysis
Intellia’s global Phase 1/2 clinical trial is evaluating the safety, tolerability, pharmacokinetics and pharmacodynamics of lonvo-z in adults with HAE Types I or II. Today’s presentation was based on a pooled analysis of all 32 patients who have received a one-time 50 mg treatment of lonvo-z via intravenous infusion in the Phase 1/2 trial. Of the 32 patients, 15 had initially received the 50 mg dose at study Day 1 (four in Phase 1 and 11 in Phase 2) and 17 were treated after unblinding of the Phase 2 clinical trial for the primary analysis (11 had originally received a 25 mg dose of lonvo-z, which was determined to be a suboptimal dose, and six had previously received placebo). The data cut-off for the analysis was August 29, 2025.

Deep, stable and durable reductions in plasma kallikrein were observed in all patients, with a mean reduction of 89% at month 24. Among the 32 patients, 31 (97%) were both attack-free and LTP-free as of the data cutoff, with 24 (75%) being attack-free and LTP-free for at least seven months (up to 32 months for patients with the longest follow-up). Of the 11 patients who initially received the 50 mg dose of lonvo-z in Phase 2, 10 were attack-free and LTP-free (nine for 7-32 months and one for