Neurogene Announces Recent Achievements and Anticipated 2026 Key Milestones for NGN-401, a Potential Best-In-Class Gene Therapy for Rett Syndrome

Neurogene announced that it has been dosed in Embolden registrational trial of NGN-401 gene therapy for Rett syndrome, an important step toward completing dosing in the second quarter of 2025. Completion of dosing in Embolden expected in second quarter of 2026. Plan to present interim data on pediatric and adolescent/adult cohorts from Phase 1/2 trial in mid-2026.

Early commercial-readiness activities underway. NGN-401 Program Updates and Recent Accomplishments. Dosed multiple participants in the Embolden??

registrational trial in the fourth quarter of 2025. Initiated 13 U.S. clinical trial sites conducting Embolden. reported positive interim data from the Phase 1/2 trial evaluating NGN-401 in females with Rett syndrome; data showed durable multidomain improvements across a full spectrum of disease severity.

Complete dosing participants in the Embolden registrational trial in the second quarter of 2026. Present interim safety and efficacy data on the pediatric cohort (ages 4-10; n=8) and the adolescent/adult cohort (ages 11; n=2) from the Phase 1/2 trials in mid-2026, including at least 12 months of follow-up for all participants. Initiate additional early commercial-readiness activities.

EXACT technology is an important advancement in gene therapy for Rett syndrome. specifically because the disorder requires a treatment approach that enables targeted levels of MECP2 transgene expression without causing overexpression-related toxic effects associated with conventional gene therapy. NGN-401 was selected by the U.S. Food and Drug Administration (FDA) for its START Pilot Program and has also received Regenerative Medicine Advance Therapy (RMAT) designation, orphan drug designation, Fast Track designation and rare pediatric designation from the FDA.

Neurogene was previously granted an INTERACT meeting with the FDA regarding the EXACT technology. NGN-401 also received Priority Medicines (PRIME) designation, orphan designation and advanced therapy medicinal product designation from the European Medicines Agency (EMA) and the Innovative Licensing and Application Pathway (ILAP) designation from the United Kingdom (UK) Medicines and Healthcare products Regulatory Agency (MHRA).