Intellia Therapeutics says HAELO trial met primary, secondary endpoints

Intellia Therapeutics (NTLA) announced topline results from the global Phase 3 HAELO clinical trial of lonvo-z in hereditary angioedema . Designed as a one-time treatment that is administered in an outpatient setting, lonvo-z is an in vivo CRISPR gene editing candidate that is intended to inactivate the kallikrein B1 gene to permanently lower kallikrein and bradykinin levels. HAELO is a randomized, double-blind, placebo-controlled Phase 3 trial 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 I or Type II HAE. Key endpoints of the trial focused on the number of HAE attacks experienced by patients, quality of life, safety and tolerability. A total of 80 patients were enrolled, with 52 receiving lonvo-z and 28 receiving placebo. Of the total population, 49% of patients were enrolled in the United States and 71% were on long-term prophylaxis therapy at study entry. Patients on LTP were required to discontinue those therapies in the weeks prior to dosing. Key findings from HAELO include: The trial met its primary endpoint. For the six-month efficacy evaluation period, a one-time infusion of lonvo-z reduced attacks by 87% versus placebo, with a mean monthly attack rate of 0.26 in the lonvo-z arm compared with 2.10 in the placebo arm. The trial met all of its key secondary endpoints with statistical significance. These included a 62% rate of patients who were entirely attack free and therapy free in the lonvo-z arm for the six-month efficacy evaluation period, compared with 11% of patients in the placebo arm. Favorable safety and tolerability data were observed for lonvo-z. The most common treatment emergent adverse events during the primary observation period were infusion-related reactions, headache and fatigue. All TEAEs reported as of the data cutoff were mild or moderate and there were no serious adverse events observed in the lonvo-z arm. As of the data cutoff, all patients who received lonvo-z at baseline or in crossover after week 28 remained LTP free.