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NGN-401

Phase 3

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

Success Probability

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Market & Valuation

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Trial Design

CONTROLLEDDMC
Total Trials1
Total Enrollment33

FDA Designations

BREAKTHROUGH_THERAPY

Clinical trial landscape

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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Recent Changes (Last 90 Days)

MEDIUMJun 10, 2026NCT05898620Status: RECRUITING → ACTIVE_NOT_RECRUITING
MEDIUMJun 10, 2026NCT05898620Status: RECRUITING → ACTIVE_NOT_RECRUITING

Frequently asked questions about NGN-401

What is NGN-401 used for?

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.

What does NGN-401 target?

NGN-401 is a gene therapy intended to deliver a functional copy of a gene to compensate for the genetic defect that causes Rett syndrome. The therapy is designed to provide the missing or faulty protein that is essential for normal neurological function, thereby targeting the root cause of the disease.

Who is developing NGN-401?

NGN-401 is being developed by Neurogene Inc., a biopharmaceutical company focused on rare neurological diseases. Neurogene is listed on the stock exchange under the ticker symbol NGNE. The company is conducting clinical trials to evaluate the safety and efficacy of NGN-401 in patients with 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 regulatory approval for commercial use. The Phase 3 trial is designed to further assess its safety and effectiveness in females with Rett syndrome.

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. The study is enrolling 33 female participants aged 3 years and older across the United States, Australia, and the United Kingdom.

Is NGN-401 FDA approved?

NGN-401 is not FDA approved. It is an investigational gene therapy currently in Phase 3 clinical trials. However, it has received Breakthrough Therapy designation from the FDA, which is intended to expedite the development and review of therapies that show promise for serious conditions like Rett syndrome.