Intellia announces long-term data from ongoing Phase 1 study of NTLA-2002

Intellia Therapeutics announced long-term data from the Phase 1 portion of the ongoing Phase 1/2 study of NTLA-2002. NTLA-2002 is an investigational in vivo CRISPR-based gene editing therapy in development as a single-dose treatment for hereditary angioedema, a rare genetic condition that leads to potentially life-threatening swelling attacks. The data were shared in an oral presentation at the European Academy of Allergy and Clinical Immunology Congress 2024, being held May 31 – June 3 in Valencia, Spain. Across all patients, a 98% mean reduction in monthly attack rate and a 99% mean reduction in moderate to severe attacks were observed after a single dose of NTLA-2002 through the latest follow-up. The median duration of follow-up was 20.1 months. At each dose level tested, a robust level of HAE attack rate reduction was achieved and long lasting. The longest attack-free interval for an individual patient post-infusion is over 26 months and ongoing. Additionally, the reduction in HAE attacks has been persistent in patients with the most severe HAE symptoms. The two patients with the highest historic monthly HAE attack rates at the start of the study were attack-free by the end of the 16-week primary observation period and have remained free of attacks through the latest follow-up. The longest attack-free duration amongst these two patients is 23.5 months and ongoing. Further, 100% of patients who discontinued prophylaxis treatment after NTLA-2002 remain free of chronic prophylaxis treatment. Eight of 10 patients had no attacks following the 16-week primary observation period. These patients have experienced ongoing attack-free durations of greater than 18 months. Of the two patients who had any attacks, one had a mild attack that did not require treatment and a single patient experienced a moderate attack. Amongst these two patients, their mean reduction in monthly HAE attack rate was 97% after a single dose of NTLA-2002 through the latest follow-up. As previously reported, administration of NTLA-2002 led to dose-dependent, robust and durable reductions in plasma kallikrein. Mean reduction in plasma kallikrein levels from baseline through latest assessment was 60%, 88%, and 95%. At all three dose levels, NTLA-2002 was well-tolerated, and the majority of adverse events were mild in severity. Consistent with previously reported results, the most frequent adverse events were infusion-related reactions and fatigue, which were mostly Grade 1 and resolved within two days. There have been no dose-limiting toxicities, no serious adverse events and no adverse events of Grade 3 or higher observed to date. No clinically significant laboratory abnormalities were observed in any patient.