Intellia Completes Enrollment for Pivotal CRISPR Therapy Study

CAMBRIDGE, Mass—Sep 18 , 2025—Intellia Therapeutics announced today that it has completed enrollment for its global Phase 3 HAELO study of lonvoguran ziclumeran (lonvo-z), a CRISPR-based therapy for treating hereditary angioedema (HAE). This milestone was reached just nine months after the first patient was dosed.The company anticipates releasing topline data in the first half of 2026 and plans to submit a biologics license application (BLA) in the second half of that year. This timeline supports a potential U.S. launch for the therapy in the first half of 2027. Dr. John Leonard, Intellia’s CEO, expressed gratitude to the patients and investigators, stating that the rapid enrollment reflects the significant unmet need for new HAE treatments.

About the HAELO Study

The HAELO trial is a randomized, double-blind, placebo-controlled study evaluating the efficacy and safety of a single 50 mg infusion of lonvo-z. The trial includes at least 60 adults and adolescents with Type I or Type II HAE, with a key endpoint being the number of HAE attacks and the proportion of patients who become attack-free.

“Lonvo-z shows great promise to positively transform the HAE treatment paradigm,” said Dr. Aleena Banerji, a principal investigator for the study.

Lonvo-z: A One-Time Treatment

Lonvo-z (formerly known as NTLA-2002) is designed to knock out the kallikrein B1 (KLKB1) gene in hepatocytes. This gene encodes prekallikrein, a precursor of plasma kallikrein, thus its knockout permanently reduces plasma kallikrein activity and halts the production of bradykinin to prevent HAE attacks. The therapy is administered intravenously as a single dose of Cas9 mRNA and KLKB1-targeting gRNA via lipid nanoparticles.

HAE is a rare genetic disease that causes severe, unpredictable swelling attacks. Existing treatments often require lifelong, frequent administration and may not prevent all breakthrough attacks. The in vivo gene-editing approach of lonvo-z, which has shown durable reductions in attack rates and kallikrein levels in earlier trials, aims to provide a long-term solution. The therapy has received several key regulatory designations, including Orphan Drug and RMAT status from the U.S. FDA, highlighting its potential to address this serious condition.