Neurogene Positive Data from Phase 1/2 Trial of Gene Therapy for Rett Syndrome

 47 total developmental milestones gained across 10 participants, with durable treatment effect and no plateau or milestone loss through 30 months of follow-up

100% of participants improved in CGI-I score and gained ≥1 developmental milestone, with an average of 4.7 milestones per participant, and all gaining ≥1 developmental milestone in the past 12 months

Developmental milestones were gained in a progressive, stepwise sequence, suggesting a restart of development post-treatment

NGN-401 at the 1E15 vg dose remains generally well-tolerated (N=35) as of data cutoff date of June 16, 2026

Dosing complete in the EmboldenTM registrational trial with no treatment-related SAEs or DLTs as of data cutoff date of June 16, 2026, with topline data anticipated in 2H 2027

https://www.businesswire.com/news/home/20260629170706/en/Neurogene-Reports-Positive-Long-term-Clinical-Data-from-Phase-12-Trial-of-NGN-401-Gene-Therapy-for-Rett-Syndrome