Intellia in vivo CRISPR gene editing therapy hits phase 3 endpoints

Intellia Therapeutics announced positive topline results from the global phase 3 HAELO clinical trial of its in vivo CRISPR gene editing candidate, lonvo-z, in hereditary angioedema (HAE).

HAELO is a randomized, double-blind, placebo-controlled trial assessing the efficacy and safety of a single 50 mg dose of lonvo-z in patients aged 16+ with Type I or II HAE. The study enrolled 80 participants (52 on lonvo-z, 28 on placebo) and evaluated attack frequency, quality of life, and safety/tolerability.

The trial met its primary endpoint, with a one-time lonvo-z infusion reducing HAE attacks by 87% versus placebo over six months (weeks 5–28), lowering the mean monthly attack rate to 0.26 vs. 2.10. All key secondary endpoints were also met, including 62% of patients in the lonvo-z group remaining attack- and therapy-free, compared to 11% with placebo.

Given the results, Intellia has initiated a rolling BLA submission to the FDA. The company is preparing for a potential U.S. launch of lonvo-z in the first half of 2027.

Designed as a one-time treatment that is administered in an outpatient setting, lonvo-z is intended to inactivate the kallikrein B1 (KLKB1) gene to permanently lower kallikrein and bradykinin levels. HAE is a rare genetic condition in which patients experience recurrent and potentially life-threatening swelling attacks in various parts of their body due to an overproduction of bradykinin.