Neurogene reports long-term Rett syndrome gene therapy data, extends cash into 2029

Neurogene Inc. reported on August 11, 2026 that positive long-term Phase 1/2 data as of a June 16, 2026 data cutoff demonstrated developmental milestones gained in a progressive, stepwise sequence, suggesting a restart of development post-treatment.¹ The company said 100% of participants, 10 total, improved on the Clinical Global Impression-Improvement scale and gained at least one developmental milestone, consistent with the composite endpoint used in the Embolden trial.¹ A total of 47 developmental milestones were gained across participants, an average of 4.7 per person, with improvement continuing through 30 months of follow-up and no plateau or milestone loss observed.¹ Seven of the 10 participants gained two or more milestones and showed improvement across two or more core Rett syndrome domains, in both pediatric and adolescent/adult participants.¹

On the registrational front, Neurogene said it completed dosing of 25 participants in the Embolden trial, with topline data still anticipated in the second half of 2027.¹ A Process Performance Qualification campaign supporting a planned BLA submission began in July 2026, with completion of PPQ runs expected by the end of 2026.¹ Separately, NGN-401 at the 1E15 vg dose has been generally well-tolerated across the Phase 1/2 trial and Embolden, totaling 35 participants, as of August 10, 2026.¹

On financing, the company completed a public follow-on offering that was oversubscribed, including full use of the underwriters' option to buy more shares, bringing in roughly $144 million in gross proceeds, and said this extended its cash runway into the first quarter of 2029.¹ Combined with $225.4 million in cash and short-term investments as of June 30, 2026, plus $134.8 million in net proceeds from the July 2, 2026 offering, Neurogene had pro forma cash, cash equivalents and short-term investments of approximately $360.2 million and expects current cash resources to fund planned operations into the first quarter of 2029.¹