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A Novel, Regulated Gene Therapy (NGN-401) Study for Females With Rett Syndrome

A Baseline-Controlled, Open-Label, Multicenter, Single-Arm, Pivotal Study to Evaluate the Efficacy, Safety, and Tolerability of NGN-401 in Subjects With Rett Syndrome (Embolden)

Status
Active, not recruiting
Phases
Phase 3
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT05898620
Enrollment
33
Registered
2023-06-12
Start date
2023-06-13
Completion date
2029-12-01
Last updated
2026-06-10

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Rett Syndrome

Keywords

Typical Rett Syndrome, MECP2, Rett Disorder, Genetic Diseases, Inborn, Genetic Diseases, X-Linked, Neurodevelopmental Disorders, Neurobehavioral Manifestations, Neurologic Manifestations, Intellectual Disability, Nervous System Diseases, Pathologic Processes, RTT

Brief summary

This study will evaluate the efficacy and safety profiles of the investigational gene therapy, NGN-401, in females with typical Rett syndrome.

Detailed description

The pivotal study, Embolden (TM), is a conversion of the phase 1/2 study and is an open-label, baseline-controlled, multicenter, single-arm study designed to assess the efficacy, safety, and tolerability of administration of NGN401, an adeno-associated viral vector serotype 9 (AAV9) using Neurogene's proprietary transgene regulation technology. NGN-401 contains a full-length human MECP2 gene and is designed to express therapeutic levels of the MeCP2 protein while avoiding overexpression. The study treatment will be given as a single administration under general anesthesia via intracerebroventricular (ICV) delivery. Each participant will be followed for efficacy and safety for 3 years after treatment, and is expected to enroll in a long-term follow-up study for 12 years.

Interventions

GENETICNGN-401

NGN-401 is a non-replicating, recombinant AAV9 carrying a full length human MECP2 transgene.

Sponsors

Neurogene Inc.
Lead SponsorINDUSTRY

Study design

Allocation
NON_RANDOMIZED
Intervention model
SEQUENTIAL
Primary purpose
TREATMENT
Masking
SINGLE (Outcomes Assessor)

Masking description

Central raters for the acquisition of a developmental milestone/skill from videos are blinded to the intervention and to the timing of the video.

Intervention model description

The study treatment will be delivered via intracerebroventricular (ICV) injection. All study participants will receive the same intervention.

Eligibility

Sex/Gender
FEMALE
Age
3 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* Females who are between the ages of ≥4 and ≤10 years for Arms 1 and 2 (Arms closed). Females who are ≥11 years of age or older for Arm 3 (Arm closed). Females who are ≥3 for Arm 4, the pivotal cohort. * Diagnosis of typical Rett syndrome with a documented disease-causing mutation in the methyl-CpG-binding protein 2 (MECP2) gene * Current anti-epileptic drug regimen has been stable for at least 12 weeks * Participant must be in the post-regression stage * Participant and caregiver should reside within a 2-hour drive of the study center for at least 3 months following treatment * Participant must have never taken trofinetide or have taken trofinetide and discontinued due to tolerability, lack of efficacy, or other reasons. Following NGN-401 dosing, trofinetide may be initiated after a specified time period and with the support of the treating clinician.

Exclusion criteria

* Normal or near normal hand function * Has a current clinically significant condition other than Rett syndrome * Presence of a concomitant medical condition that precludes intracerebroventricular administration, or use of anesthetics or immune suppression needed for study related procedures Other inclusion and

Design outcomes

Primary

MeasureTime frameDescription
Efficacy of NGN-40152 WeeksResponders will be defined as participants who: * Attain a CGI-I score of ≤ 3 ("minimally improved"); * and gain any one developmental milestone/skill from a list of 28, as captured through standardized video recordings and independently verified by blinded central raters.

Countries

Australia, United Kingdom, United States

Contacts

STUDY_DIRECTORJulie Jordan, MD

Neurogene Inc.

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Jun 11, 2026