Intellia Therapeutics has announced compelling long-term data from the Phase 1 portion of its ongoing Phase 1/2 study of NTLA-2002, an investigational in vivo CRISPR-based gene editing therapy for hereditary angioedema (HAE). The results, presented at the European Academy of Allergy and Clinical Immunology (EAACI) Congress 2024 in Valencia, Spain, demonstrate the potential of this single-dose treatment to provide a functional cure for patients with this rare genetic condition.
The data showed that a single administration of NTLA-2002 led to a remarkable 98% mean reduction in monthly HAE attack rate across all patients, with an average follow-up period exceeding 20 months. Even more striking, eight of the ten patients in the study have remained completely attack-free following the initial 16-week primary observation period, with attack-free durations extending beyond 18 months.
"These unprecedented data strengthen our view that NTLA-2002 could be a groundbreaking treatment for people living with hereditary angioedema," said Intellia President and Chief Executive Officer John Leonard, M.D. "After a single dose of our investigational in vivo CRISPR-based therapy, patients experienced durable elimination of their attacks. We are thrilled to see that the majority of patients have been attack free for over 18 months or longer."
Robust and Durable Response Across All Dose Levels
The Phase 1 study evaluated three dose levels of NTLA-2002 administered via intravenous infusion: 25 mg (3 patients), 50 mg (4 patients), and 75 mg (3 patients). All dose groups demonstrated substantial reductions in HAE attacks, with the longest attack-free interval for an individual patient extending beyond 26 months and still ongoing.
Particularly noteworthy was the response in patients with severe disease. The two patients with the highest historical monthly HAE attack rates at baseline (16.8 and 14.0 attacks per month, respectively) became attack-free by the end of the 16-week primary observation period and have remained free of attacks through the latest follow-up, with the longest attack-free duration among these two patients reaching 23.5 months and continuing.
Additionally, all patients who discontinued prophylaxis treatment after receiving NTLA-2002 have remained free of chronic prophylaxis treatment, suggesting the potential for this one-time therapy to replace current treatment regimens that often require lifelong administration.
Mechanism of Action and Biomarker Data
NTLA-2002 is designed to prevent HAE attacks by inactivating the kallikrein B1 (KLKB1) gene, which encodes for prekallikrein, the kallikrein precursor protein. Consistent with this mechanism, the treatment led to dose-dependent, robust, and durable reductions in plasma kallikrein levels.
Mean reductions in plasma kallikrein levels from baseline through the latest assessment were 60% in the 25 mg dose group (at 88 weeks), 88% in the 50 mg dose group (at 72 weeks), and 95% in the 75 mg dose group (at 88 weeks). These sustained reductions in kallikrein levels correlate with the observed clinical benefits.
Favorable Safety Profile
Across all three dose levels, NTLA-2002 was well-tolerated, with the majority of adverse events being mild in severity. The most frequent adverse events were infusion-related reactions and fatigue, which were mostly Grade 1 and resolved within two days.
Importantly, 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, further supporting the favorable safety profile of this CRISPR-based therapy.
Hereditary Angioedema: A Rare and Debilitating Condition
HAE is a rare genetic disease affecting approximately one in 50,000 people. It is characterized by severe, recurring, and unpredictable inflammatory attacks in various organs and tissues of the body, which can be painful, debilitating, and potentially life-threatening.
Current treatment options for HAE often involve lifelong therapies requiring chronic intravenous or subcutaneous administration as frequently as twice per week, or daily oral administration. Despite these chronic treatments, breakthrough attacks still occur, highlighting the significant unmet need for more effective and convenient therapeutic options.
Future Development Plans
Intellia has completed enrollment of the randomized, placebo-controlled Phase 2 study evaluating the 25 mg and 50 mg doses of NTLA-2002. The company plans to report topline results mid-year 2024, with detailed results expected to be presented at a medical meeting later in the year.
Subject to regulatory feedback, Intellia expects to begin a pivotal Phase 3 trial of NTLA-2002 in the second half of 2024, advancing this potentially transformative therapy closer to patients in need.
NTLA-2002 has already received several important regulatory designations, including Orphan Drug and RMAT Designation by the U.S. Food and Drug Administration, the Innovation Passport by the U.K. Medicines and Healthcare products Regulatory Agency, Priority Medicines (PRIME) Designation by the European Medicines Agency, and Orphan Drug Designation by the European Commission.
Pioneering In Vivo CRISPR Applications
NTLA-2002 represents a significant advancement in the application of CRISPR gene editing technology for therapeutic purposes. As part of Intellia's in vivo program, the therapy is administered intravenously, with proprietary delivery technology enabling precise editing of disease-causing genes directly within specific target tissues.
The impressive long-term data from this study not only support the potential of NTLA-2002 as a functional cure for HAE but also validate the broader approach of using in vivo CRISPR-based therapies to address genetic diseases. If successful in later-stage trials, NTLA-2002 could become the first one-time treatment for HAE, potentially transforming the treatment paradigm for this debilitating condition.
