Neurogene Inc. announced initial safety and tolerability data from its ongoing Phase 1/2 gene therapy clinical trial for Rett syndrome, which showed that NGN-401 was generally well-tolerated by all three patients dosed, with follow-up of approximately nine, six and three months post-dosing. These data were presented during the American Society of Gene and Cell Therapy (ASGCT) Annual Meeting. The Phase 1/2 open-label trial is evaluating the safety, tolerability, and preliminary efficacy of two dose levels of NGN-401 delivered via one-time intracerebroventricular (ICV) infusion. Enrollment of female patients ages 4-10 years old with classic Rett Syndrome and a Clinical Global Impression-Severity (CGI-S) score of 4-6 is ongoing in low-dose Cohort 1 and high-dose Cohort 2. NGN-401 has been generally well-tolerated by all three patients. All adverse events (AEs) related to NGN-401 have been mild, or Grade 1, and transient or resolving. Most AEs are known potential risks of adeno-associated virus (AAV), including asymptomatic laboratory value changes. There have been no signs or symptoms indicative of MeCP2 overexpression toxicity reported in any of the three patients, including the patient with a mild variant that is predicted to result in residual MeCP2 expression. There have been no treatment-emergent or ICV procedure-related serious AEs (SAEs).
Neurogene continues to expect to provide interim clinical data, including efficacy data, from Cohort 1 in the fourth quarter of 2024 and additional interim data, including from Cohort 2, in the second half of 2025.