Drug pipeline
Late‑stage trial supports gene editing strategy for hereditary angioedema
Intellia Therapeutics announced positive phase 3 results from the HAELO trial evaluating lonvoguran ziclumeran (lonvo‑z), an investigational one-time CRISPR-based therapy designed to durably suppress kallikrein production in hereditary angioedema.
HAELO was a randomized, double-blind, placebo-controlled study involving 80 adults and adolescents with type I or II hereditary angioedema. During the prespecified six‑month efficacy period, lonvo‑z reduced the mean monthly attack rate to 0.26 compared with 2.10 with placebo, corresponding to an 87% relative reduction (P<0.0001). Notably, 62% of treated patients were completely attack free and off all background prophylaxis, vs. 11% in the placebo arm.
The safety profile was favorable. Treatment‑emergent adverse events were mild to moderate and primarily included infusion‑related reactions, headache, and fatigue. No serious adverse events were observed, and all treated patients remained free of long‑term prophylactic therapy at the data cutoff.
The company announced that it's initiated a submission to FDA to seek regulatory approval.
“As the first phase 3 data reported for an in vivo gene editing therapy, today’s HAELO results represent a profound milestone,” said John Leonard, M.D., Intellia President and Chief Executive Officer. “For those patients who have spent years battling unpredictable breakthrough swelling attacks, anxiety about their next attack or the many burdens associated with chronic prophylactic treatment, lonvo-z represents a potential paradigm shift in treatment. These data affirm lonvo-z’s potential, with one dose, to offer prolonged freedom from both attacks and the need for ongoing therapy.”
Source: Intellia Therapeutics. (2026, April 27). Press release. Intellia Therapeutics Reports Positive Phase 3 Results in Hereditary Angioedema, Marking a Global First for In Vivo Gene Editing