FDA Grants Priority Review to Intellia BLA for CRISPR Therapy Lonvo-Z

Intellia Therapeutics (NTLA ) announced on September 8, 2026, that the U.S. Food and Drug Administration has accepted its Biologics License Application for lonvoguran ziclumeran (lonvo-z) in hereditary angioedema and granted the filing Priority Review, setting a Prescription Drug User Fee Act target action date of March 10, 2027. The FDA has also advised the Cambridge, Massachusetts-based company that it is not currently planning to hold an advisory committee meeting to discuss the application, according to the company’s announcement.

If approved, lonvo-z would be the world’s first in vivo CRISPR-based therapy and the only one-time treatment for HAE, the company stated. The candidate, formerly known as NTLA-2002, is designed to permanently lower kallikrein by inactivating the kallikrein B1 (KLKB1) gene with a single dose administered in an outpatient setting.

Phase 3 Data Behind the Filing

The BLA is supported by positive data from Intellia‘s global Phase 3 HAELO clinical trial, which fully enrolled 80 patients in nine months. The study was designed to evaluate the efficacy and safety of a one-time 50 milligram dose of lonvo-z in adults and adolescents aged 16 years and older with Type 1 or Type 2 HAE.

According to the company, HAELO met its primary and all key secondary endpoints, demonstrating an 87% reduction (p<0.0001) in mean monthly attacks for lonvo-z compared with placebo during the efficacy evaluation period spanning weeks 5 to 28. In addition, 62% of patients in the lonvo-z arm were entirely attack free and HAE therapy free for the six-month efficacy evaluation period, compared with 11% of patients in the placebo arm (p<0.0001). As of the February 10, 2026, data cutoff, all patients who received lonvo-z at baseline or in crossover after week 28 remained free from long-term prophylaxis therapy, Intellia reported.

Favorable safety and tolerability data were observed for lonvo-z as of the data cutoff, the company stated. The most common treatment emergent adverse events during the primary observation period, defined as infusion through week 28, that were higher in the lonvo-z group compared with placebo were infusion-related reactions, headache, fatigue, back pain, and upper respiratory tract infection. All reported treatment emergent adverse events were mild or moderate, and no serious adverse events were observed in the lonvo-z arm.

“Today marks an important milestone for the patients we are committed to serving and for Intellia’s pioneering work in the field of in vivo gene editing,” said John Leonard, M.D., Intellia President and Chief Executive Officer. “Backed by compelling Phase 3 data, we believe lonvo-z could fundamentally change the way HAE is treated and are excited by its potential to become the world’s first approved in vivo CRISPR-based therapy. With the FDA’s Priority Review underway, our team is well prepared to deliver this one-time treatment to patients who are waiting for new options.”

Joshua Jacobs, M.D., Medical Director of Allergy and Asthma Clinical Research, Inc., and a HAELO trial investigator, added: “HAE is an unpredictable disease that can be responsible for profound disability and place patients at risk for fatal attacks. Today’s announcement is exciting because it advances us one step closer to potentially having a one-time treatment option available for patients who continue to be burdened by this chronic disease.”

Regulatory Path and Designations

The September 8, 2026, acceptance follows Intellia’s April 27, 2026, announcement that it had initiated a rolling submission of the BLA for lonvo-z. The rolling submission proceeded under the Regenerative Medicine Advanced Therapy (RMAT) designation that the FDA granted to lonvo-z for the treatment of HAE; under that framework, Intellia was able to submit portions of the BLA on an ongoing basis, giving the FDA an opportunity to expedite its review. Intellia also participated in the FDA’s Chemistry, Manufacturing, and Controls (CMC) Development and Readiness Pilot, a program that allows sponsors to discuss their CMC product development strategies and goals with FDA review staff and address their questions, with the increased communication intended to help sponsors complete CMC activities supporting application submission and earlier patient access.

Lonvo-z holds five regulatory designations, according to the company: Orphan Drug and RMAT designations from the FDA, the Innovation Passport from the U.K. Medicines and Healthcare products Regulatory Agency (MHRA), Priority Medicines (PRIME) designation from the European Medicines Agency, and Orphan Drug Designation from the European Commission. The therapy is based on Nobel Prize-winning CRISPR/Cas9 technology.

HAE is a rare, genetic disease characterized by severe, recurring and unpredictable inflammatory attacks in various organs and tissues of the body, which can be painful, debilitating and life-threatening. It is estimated that one in 50,000 people are affected by HAE. Current treatment options include preventative and on-demand therapies such as long- and short-term prophylaxis; these often involve lifelong treatment requiring chronic intravenous or subcutaneous administration as often as twice per week, or daily oral administration, to ensure constant pathway suppression for disease control, and breakthrough attacks may still occur despite chronic administration. Kallikrein inhibition is a clinically validated strategy for the preventive treatment of HAE attacks.

In its April 27, 2026, filing announcement, Intellia stated that if the BLA were accepted and approved, it planned to launch lonvo-z commercially in the first half of 2027.