Neurogene announces FDA agreement on registrational trial design for NGN-401 gene therapy in Rett syndrome

Neurogene Inc.

• FDA agreed on single-arm, open-label, baseline-controlled design; N=18 proposed; primary endpoint: CGI-I improvement plus gain of developmental milestone.
• Phase 1/2 fully enrolled; 5 participants dosed in 1H2025; no HLH/hyperinflammatory syndrome observed at 1E15 vg dose.
• First four participants achieved 23 developmental milestones across hand function, communication, and ambulation by 3–15 months.
• Cash, cash equivalents & investments of $292.6M as of March 31, 2025; runway extended into early 2028.
• Updated efficacy and safety data expected in second half of 2025.