NGN-401

NEW YORK, NY, USA I November 18, 2024 I Neurogene Inc. (Nasdaq: NGNE), a clinical-stage company founded to bring life-changing genetic medicines to patients and families affected by rare neurological diseases, today announced an update on its ongoing Phase 1/2 open-label clinical trial evaluating NGN-401 gene therapy for the treatment of Rett syndrome. As previously disclosed, on November 11,2024, Neurogene became aware of an emerging treatment-related serious adverse event (SAE) in a trial participant who received NGN-401 at a dose of 3E15 vg (high-dose cohort). This participant, who was dosed on November 5, subsequently experienced signs of a systemic hyperinflammatory syndrome, a rare and life-threatening immune response that has been reported with systemic exposure to high doses of AAV. Hyperinflammatory syndromes are associated with aberrant cytokine release and include hemophagocytic lymphohistiocytosis (HLH) and multisystem inflammatory syndrome. The participant is in critical condition, and the case is continuing to evolve. “We are deeply saddened for the family. While no words could possibly provide comfort to her family, we ask the Rett syndrome community to join us in sending heartfelt thoughts to her family, friends and the dedicated clinicians who are caring for her,” said Rachel McMinn, Ph.D., Founder and Chief Executive Officer of Neurogene. “The safety of the participants in our clinical trial is and remains our foremost priority as we work to find solutions for this devastating disease.” In a commitment to full transparency with the U.S. Food and Drug Administration (FDA), Neurogene proactively engaged with the FDA under the START program following the Company’s notification of the SAE. The FDA completed a review of the safety data for NGN-401 and allowed Neurogene to proceed with the Phase 1/2 trial using the 1E15 vg dose (low-dose cohort). Neurogene paused further use of the 3E15 vg dose (high-dose cohorts) upon initial notification of the SAE and does not plan to enroll any further participants at the 3E15 vg dose level. To date, there have been no other treatment-related SAEs in the clinical trial, including in the five participants who received the 1E15 vg dose (low-dose cohort) and in the first two participants who received the 3E15 vg dose (high-dose cohort) of NGN-401. All treatment-related AEs in the 1E15 vg cohort (low-dose cohort) have been Grade 1 (mild). Most treatment-related AEs are known potential risks of AAV, have been responsive to steroids, and have resolved or are resolving. There have been no signs or symptoms indicative of MeCP2 overexpression toxicity. In addition, there have been no intracerebroventricular (ICV) procedure-related AEs. Neurogene no longer anticipates completing enrollment in the 1E15 vg cohort (low-dose cohort) of NGN-401 in the fourth quarter of 2024 as the Company updates the protocol to reflect the discontinuation of the 3E15 vg dose. About Neurogene The mission of Neurogene is to treat devastating neurological diseases to improve the lives of patients and families impacted by these rare diseases. Neurogene is developing novel approaches and treatments to address the limitations of conventional gene therapy in central nervous system disorders. This includes selecting a delivery approach to maximize distribution to target tissues and designing products to maximize potency and purity for an optimized efficacy and safety profile. The Company’s novel and proprietary EXACT™ transgene regulation platform technology allows for the delivery of therapeutic levels while limiting transgene toxicity associated with conventional gene therapy. Neurogene has constructed a state-of-the-art gene therapy manufacturing facility in Houston, Texas. CGMP production of NGN-401 was conducted in this facility and will support pivotal clinical development activities. For more information, visit www.neurogene.com . SOURCE: Neurogene