Neurogene Reports Positive Interim Results for Rett Syndrome Gene Therapy

Neurogene has shared promising interim Phase I/II results for NGN-401, its gene therapy for females aged 4–10 years with Rett syndrome. All paediatric participants showed meaningful developmental improvements regardless of baseline disease severity. Safety findings from ten subjects showed that NGN-401 at the 1E15 vg dose was generally well tolerated, with only mild to moderate treatment-related adverse events typical of AAV therapies. Most side effects have resolved or are improving, and no cases of haemophagocytic lymphohistiocytosis were observed.

Among eight paediatric subjects with efficacy data, a total of 35 new developmental milestones or functional gains were recorded, including improvements in communication, ambulation, gross motor skills, hand function, and fine motor abilities. These durable gains exceed expectations for the upcoming Embolden registrational trial.

Neurogene highlighted that NGN-401’s targeted brain delivery and use of the full-length human gene may support best-in-class potential. Additional data are expected in 2026.

17-11-2025