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Updated: Jun 9, 2025
CRISPR/Cas9-mediated Targeted Integration In Vivo Using a Homology-mediated End Joining-based Strategy
Published on: March 12, 2018
CRISPR-Based Therapy for Hereditary Angioedema
Danny M Cohn1, Padmalal Gurugama1, Markus Magerl1
1From Amsterdam Cardiovascular Sciences, Amsterdam University Medical Center, University of Amsterdam, Amsterdam (D.M.C., R.S.P); Cambridge University Hospitals, NHS Foundation Trust, Cambridge, United Kingdom (P.G.); the Institute of Allergology, Charité-Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, and Immunology and Allergology, Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Berlin (M.M.), and the Department of Children and Adolescents, University Hospital Frankfurt, Goethe University Frankfurt, Frankfurt (E.A.-P.) - all in Germany; the Department of Medicine, Campbelltown Hospital and Western Sydney University, Sydney (C.H.K.); University of Lille, U1286-INFINITE-Institute for Translational Research in Inflammation, F-59000, INSERM, and the Department of Internal Medicine and Clinical Immunology, CHU Lille, National Reference Center for Angioedema (CREAK), Lille (D.L.), and CREAK, Angioedema Center of Reference and Excellence (ACARE), Grenoble Alpes University Hospital, and the Translational Research in Autoimmunity and Inflammation Arm (T-RAIG), French National Center for Scientific Research (CNRS), Grenoble (L.B.) - all in France; Intellia Therapeutics, Cambridge, MA (D.M., J.S.B., M.Y.S., A.G., Y.X., A.M.A., D.L.); and the Department of Immunology, Auckland City Hospital, and the Department of Medicine, University of Auckland - both in Auckland, New Zealand (K.L., H.J.L.).
Background:
Hereditary angioedema is a rare genetic disease characterized by severe and unpredictable swelling attacks. NTLA-2002 is an in vivo gene-editing therapy that is based on clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9. NTLA-2002 targets the gene encoding kallikrein B1 (KLKB1). A single dose of NTLA-2002 may provide lifelong control of angioedema attacks.
Methods:
In this phase 2 portion of a phase 1-2 trial, we randomly assigned adults with hereditary angioedema in a 2:2:1 ratio to receive NTLA-2002 in a single dose of 25 mg or 50 mg or placebo. The primary end point was the number of angioedema attacks per month (the monthly attack rate) from week 1 through week 16. Secondary end points included safety, pharmacokinetics, and pharmacodynamics (i.e., the change from baseline in total plasma kallikrein protein level); exploratory end points included patient-reported outcomes.
Results:
Of the 27 patients who underwent randomization, 10 received 25 mg of NTLA-2002, 11 received 50 mg, and 6 received placebo. From week 1 through week 16, the estimated mean monthly attack rate was 0.70 (95% confidence interval [CI], 0.25 to 1.98) with 25 mg of NTLA-2002, 0.65 (95% CI, 0.24 to 1.76) with 50 mg, and 2.82 (95% CI, 0.80 to 9.89) with placebo; the difference in the estimated mean attack rate with NTLA-2002 as compared with placebo was -75% with 25 mg and -77% with 50 mg. Among patients who received NTLA-2002, 4 of the 10 patients who received 25 mg (40%) and 8 of the 11 who received 50 mg (73%) were attack-free with no additional treatment during the period from week 1 through week 16. The most common adverse events among patients who received NTLA-2002 were headache, fatigue, and nasopharyngitis. The mean percent change in total plasma kallikrein protein levels from baseline to week 16 was -55% with 25 mg and -86% with 50 mg; levels remained unchanged with placebo.
Conclusions:
NTLA-2002 administered in a single dose of 25 mg or 50 mg reduced angioedema attacks and led to robust and sustained reduction in total plasma kallikrein levels in patients with hereditary angioedema. These results support continued investigation in a larger phase 3 trial. (Funded by Intellia Therapeutics; ClinicalTrials.gov number, NCT05120830; EudraCT number, 2021-001693-33.).
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