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NGN-401

Phase 3

Rett Syndrome | Gene therapy | Rare Disease |Neurogene Inc.|Trials Updated: Jun 10, 2026

NGN-401 development status

Highest phase Phase 3
Registered trials 1 across 1 sponsor since Jun 2023

NGN-401 target and mechanism

Molecular targetMECP2
ModalityGene therapy

Success Probability

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Market & Valuation

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Trial Design

CONTROLLEDDMC
Total Trials1
Total Enrollment33

FDA Designations

BREAKTHROUGH_THERAPY

NGN-401 clinical trials

NGN-401 · 1 trial · 1 indication

Phase 3 1
NCT05898620A Novel, Regulated Gene Therapy (NGN-401) Study for Females With Rett SyndromeRett Syndrome
ACTIVE NOT_RECRUITING33 Analytics
PHASE3ACTIVE NOT_RECRUITING
A Novel, Regulated Gene Therapy (NGN-401) Study for Females With Rett Syndrome
Rett SyndromeUnlock trial analytics

Study Endpoints

Primary Endpoints

Efficacy of NGN-401
52 Weeks

Responders 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.

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Study Design & Arms

AllocationNON_RANDOMIZED
MaskingSINGLE
ModelSEQUENTIAL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Pediatric 1e15 vg dose (fully enrolled)EXPERIMENTALDose Level 1 for ages 4-10 years
Adolescent/Adult 1e15 vg Dose (fully enrolled)EXPERIMENTALDose Level 1 for ages 11 years \& above
Pediatric 3e15 vg dose (discontinued)EXPERIMENTALDose Level 2 for ages 4-10 years (discontinued)
Pivotal CohortEXPERIMENTALDose Level 1 for ages 3 and above

Interventions

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

Age Range3 Years to N/A
SexFEMALE
Healthy VolunteersNo
Study Sites16

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 mutat...

Countries:United StatesAustraliaUnited Kingdom
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Competitive Landscape -Acute Respiratory Distress Syndrome 27 trials (matched to "Rett Syndrome")

Top 2 of 7 competitors

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Frequently asked questions about NGN-401

What is NGN-401 used for in Rett Syndrome?

NGN-401 is an investigational gene therapy being developed for the treatment of Rett Syndrome in females. It is designed to address the underlying genetic cause of the condition. The therapy is currently in Phase 3 clinical development and has not yet been approved by regulatory authorities.

How does NGN-401 work?

NGN-401 is a gene therapy that targets the MECP2 gene. Rett Syndrome is caused by mutations in this gene, and the therapy aims to deliver a functional copy of MECP2 to cells. This approach is intended to compensate for the defective gene and potentially alleviate disease symptoms.

Who is developing NGN-401?

NGN-401 is being developed by Neurogene Inc., a biopharmaceutical company traded on the stock exchange under the ticker symbol NGNE. The company is focused on developing treatments for rare neurological diseases and is advancing NGN-401 through clinical trials for Rett Syndrome.

What phase is NGN-401 in?

NGN-401 is currently in Phase 3 clinical development. It is an investigational therapy, meaning it has not yet received FDA approval. The drug has been granted Breakthrough Therapy designation by the FDA, which is intended to expedite the development and review of therapies for serious conditions.

What clinical trials is NGN-401 in?

NGN-401 is being studied in a Phase 3 clinical trial with the identifier NCT05898620. This trial is titled 'A Novel, Regulated Gene Therapy (NGN-401) Study for Females With Rett Syndrome' and is currently active but not recruiting participants. The study is enrolling 33 female patients aged 3 years and older.

Is NGN-401 the same as other gene therapies for Rett Syndrome?

NGN-401 is a distinct gene therapy candidate developed by Neurogene Inc. It is designed to deliver the MECP2 gene and is currently in Phase 3 trials. While other gene therapies for Rett Syndrome may exist, NGN-401 is a unique investigational product with its own clinical trial program.