NEW YORK, NY — 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 that the U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy designation to NGN-401, an investigational gene therapy in late-stage clinical development as a potential best-in-class treatment for Rett syndrome.
The Breakthrough Therapy designation was based on the FDA’s review of interim efficacy and safety data from the Phase 1/2 trial as of the data cutoff date of October 30, 2025, including patient-level data and supporting video documentation, demonstrating clinically meaningful and durable functional improvements across multiple Rett syndrome domains with continued skill acquisition over time.
NGN-401 is being evaluated as a one-time treatment for Rett syndrome and is designed to deliver the full-length human MECP2 gene under the control of Neurogene’s proprietary EXACT™ transgene regulation technology. It is delivered through intracerebroventricular administration to achieve the broadest targeting directly to the brain and nervous system based on nonclinical biodistribution data. NGN-401 is currently being evaluated in the Embolden™ registrational clinical trial, with completion of dosing expected in the second quarter of 2026.
“The FDA’s decision to grant Breakthrough Therapy designation validates the clinically meaningful, durable and multidomain functional improvements observed with NGN-401, including continued skill acquisition observed over time, and underscores the significant unmet medical need of those living with Rett syndrome,” stated Rachel McMinn, Ph.D., Founder and Chief Executive Officer of Neurogene. “We appreciate the Agency’s continued engagement, including through our participation in the START Pilot Program and now our Breakthrough Therapy designation, to support the rapid advancement of NGN-401.”
Breakthrough Therapy designation is intended to expedite the development and review of medicines for the treatment of serious conditions which have shown preliminary clinical evidence indicating the potential for substantial improvement over available therapies on a clinically significant endpoint. The benefits of Breakthrough Therapy designation include eligibility for Priority Review, rolling submission of sections of the Biologics License Application and FDA’s organizational commitment to help determine an efficient route to approval.
This designation for NGN-401 is the latest of several regulatory designations granted by FDA, including Regenerative Medicine Advanced Therapy (RMAT) and Rare Pediatric Disease designations, and selection for FDA’s Support for Clinical Trials Advancing Rare Disease Therapeutics (START) Pilot Program.
About Neurogene
Neurogene (NASDAQ: NGNE) is a clinical-stage biotechnology company focused on developing life-changing genetic medicines for people and their families impacted by devastating neurological diseases. The Company is using a biology-first approach paired with optimized delivery to develop purpose-built genetic medicines powered by its novel and proprietary EXACT™ transgene regulation technology. Neurogene is advancing its lead gene therapy program, NGN-401, as a potential best-in-class, one-time treatment for Rett syndrome. For more information, visit neurogene.com or follow on LinkedIn.
About NGN-401
NGN-401 is an investigational AAV9 gene therapy in late-stage clinical development as a potential best-in-class, one-time treatment for Rett syndrome. It is the only clinical candidate to deliver the full-length human MECP2 gene and includes Neurogene’s EXACT™ transgene regulation technology, which is designed to deliver consistent, tightly controlled MeCP2 protein expression on a cell-by-cell basis. NGN-401 is delivered through intracerebroventricular administration to achieve the broadest targeting directly to the brain and nervous system based on nonclinical biodistribution data. NGN-401 is being evaluated in the Embolden™ registrational clinical trial. Interim data from the Phase 1/2 trial (as of October 30, 2025) have shown that participants experienced multidomain, durable gains with continued skill acquisition observed over time, and NGN-401 at the 1E15 vg dose has been generally well-tolerated. NGN-401 has received Breakthrough Therapy, Regenerative Medicine Advanced Therapy, Fast Track, Orphan Drug and Rare Pediatric Disease designations and selection for the START Pilot Program from the U.S. Food and Drug Administration, Advanced Therapy Medicinal Product, Orphan and Priority Medicines designations from the European Medicines Agency and Innovative Licensing and Application Pathway designation from the United Kingdom Medicines and Healthcare products Regulatory Agency.
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Mike Devine
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