Neurogene to Present New NGN-401 Gene Therapy Data for Rett Syndrome at ESGCT 2026
Neurogene Inc., a clinical-stage biotechnology company focused on developing genetic medicines for rare neurological diseases, announced that it will present new data from its NGN-401 gene therapy program for Rett syndrome at the European Society of Gene and Cell Therapy (ESGCT) 33rd Annual Congress. The congress will take place October 27–30, 2026, in Hamburg, Germany, bringing together researchers, clinicians and biotechnology professionals to discuss advances in gene and cell therapy.
The presentations will feature preclinical research and clinical observations addressing key challenges in developing adeno-associated virus (AAV)-based gene therapies for Rett syndrome. Neurogene plans to share findings on the speed of transgene expression following single-stranded AAV delivery, approaches to regulating MECP2 transgene expression at the individual-cell level, and the potential role of its proprietary EXACT™ transgene regulation technology.
The company will also present information on intracerebroventricular (ICV) administration, a delivery approach used to introduce therapeutic agents into the cerebrospinal fluid, as part of its broader strategy for delivering gene therapies to the central nervous system (CNS).
The scientific program will include an invited talk on self-regulating gene therapy for Rett syndrome and several poster presentations examining transgene regulation, CNS delivery methods and the relationship between gene expression kinetics and the early onset of clinical benefit observed in the NGN-401 Phase 1/2 trial.
These presentations are intended to provide additional insight into the scientific rationale behind NGN-401 and the development strategies Neurogene is pursuing to address the complex biological challenges associated with treating Rett syndrome through gene replacement.
Addressing Key Challenges in Gene Therapy for Rett Syndrome
Rett syndrome is a rare neurological disorder that primarily affects girls and is associated with changes in neurological development, communication, movement and other essential functions. The condition is most commonly caused by mutations in the MECP2 gene, which plays an important role in regulating the activity of other genes and supporting normal brain development and function.
Because MECP2 is involved in multiple cellular processes, developing a gene therapy for Rett syndrome requires careful consideration of both therapeutic gene delivery and the amount of protein produced by the introduced genetic material.
Gene replacement approaches aim to provide cells with a functional copy of a gene that is missing or not functioning correctly. However, the therapeutic strategy must account for the biological requirements of the target gene, the distribution of the treatment throughout the CNS and the possibility that different cells may respond differently to the introduced genetic material.
For MECP2, regulating expression is particularly important. The goal is not simply to deliver a functional gene, but to achieve an appropriate level of expression across relevant cells. Excessive MECP2 expression can itself cause neurological problems, making controlled expression an important consideration in therapeutic development.
Neurogene’s NGN-401 program is designed to address Rett syndrome through an AAV-based gene therapy approach incorporating the company’s EXACT transgene regulation technology. The platform is intended to support controlled transgene expression, addressing one of the central challenges in developing gene replacement therapies for conditions involving genes that require precise regulation.
At ESGCT 2026, Neurogene will present new preclinical findings examining how these regulatory strategies perform and how gene expression develops following administration.
Investigating Transgene Expression Following Single-Stranded AAV Delivery
One of the major topics at the congress will be the relationship between gene delivery and the onset of transgene expression.
AAV vectors are widely investigated in gene therapy because they can deliver genetic material to target cells. However, the time required for an introduced gene to become active can depend on the vector design, the type of genetic material delivered, the target tissue and the biological characteristics of the recipient cells.
Neurogene’s planned presentation, titled Expression Kinetics and Clinical Onset of Benefit Following Single-Stranded AAV Delivery of NGN-401 in Rett Syndrome, will examine expression kinetics following single-stranded AAV delivery alongside observations concerning the early time to response in the NGN-401 Phase 1/2 clinical trial.
Expression kinetics refers to how gene expression develops over time after a therapeutic vector has been administered. Understanding this process is important because the speed at which a therapeutic gene becomes active may influence the timing of its potential biological effects.
In AAV-based gene therapy, the vector must reach target cells and deliver the genetic material required for transgene expression. The subsequent process involves cellular mechanisms that allow the introduced genetic instructions to become active and produce the intended protein.
Single-stranded AAV vectors deliver DNA that must undergo additional intracellular processing before efficient transgene expression can occur. The timing and extent of expression can vary depending on several biological and technical factors.
By characterizing expression kinetics in a preclinical setting and considering observations from the NGN-401 Phase 1/2 trial, Neurogene aims to provide additional information about the relationship between gene delivery, transgene activity and the early clinical response observed in treated patients.
The presentation will be relevant to researchers evaluating how vector design and gene expression characteristics may influence the development of genetic medicines for neurological disorders.
However, preclinical expression findings and early clinical observations represent different types of evidence. Further clinical investigation will be necessary to determine the consistency, durability and clinical significance of any observed responses in patients with Rett syndrome.
Evaluating miRNA-Based Regulation of MECP2 Expression
Another key component of Neurogene’s ESGCT program will focus on microRNA (miRNA)-based approaches to regulating transgene expression.
The presentation, titled Myth versus measurement: direct CNS comparison of two miRNA based regulated gene therapies in a mosaic model of Rett syndrome, will examine two miRNA-based gene regulation approaches in a preclinical model of Rett syndrome.
MicroRNAs are small regulatory RNA molecules that help control gene expression by influencing how specific messenger RNAs are processed or used by cells. In gene therapy, miRNA-based regulatory elements can be incorporated into a therapeutic construct to influence where and how strongly a transgene is expressed.
This approach is particularly relevant to MECP2 gene therapy because maintaining appropriate expression levels is a central development objective. A treatment that produces insufficient MECP2 may not achieve the intended therapeutic effect, while excessive expression could create additional safety concerns.
Neurogene’s research will compare two miRNA-based regulated gene therapy approaches directly in the CNS using a mosaic model of Rett syndrome.
A mosaic model can help researchers investigate how different populations of cells respond to a genetic intervention. This is important for neurological disorders in which the distribution of a therapeutic gene and the level of expression in individual cells may influence the overall biological response.
Evaluating expression on a cell-by-cell basis can provide information that may be difficult to obtain from measurements of average expression across an entire tissue. An overall average may not fully capture differences between individual cells, including whether some cells express the therapeutic gene at higher or lower levels than others.
The planned comparison will provide an opportunity to assess how different regulatory approaches influence transgene expression within the CNS. The results may help researchers better understand the performance of miRNA-based regulation and inform the design of gene therapies intended to maintain a more appropriate expression profile.
Neurogene will also discuss its proprietary EXACT transgene regulation technology as part of the company’s broader effort to address the expression-control challenges associated with treating Rett syndrome.
EXACT Technology and the Development of Self-Regulating Gene Therapy
Neurogene’s invited presentation, titled Self-regulating gene therapy for Rett syndrome, will focus on the company’s approach to controlling therapeutic gene expression.
The EXACT platform is designed to support transgene regulation in genetic medicines. Its relevance to the NGN-401 program stems from the need to deliver a functional MECP2 gene while controlling expression levels in target cells.
Self-regulating gene therapy strategies seek to incorporate mechanisms that influence the activity of the therapeutic genetic material. Such approaches are being investigated as a way to address conditions in which the amount of protein produced is as important as the delivery of the gene itself.
For Rett syndrome, this consideration is central to therapeutic design. A successful approach must account for the role of MECP2 in normal neurological function and the potential consequences of producing too little or too much of the protein.
Through its EXACT technology, Neurogene aims to address this challenge by incorporating transgene regulation into its therapeutic strategy. The upcoming presentation will provide an overview of the platform and its application to NGN-401.
The company’s preclinical research comparing miRNA-based regulatory approaches is expected to complement this discussion by providing additional information about how different regulatory designs behave in the CNS.
Together, these presentations will highlight the importance of integrating gene delivery and expression control into the development of gene therapies for neurological conditions.
ICV Administration as a Strategy for Central Nervous System Delivery
Neurogene will also present a poster titled Gene Therapy Targeting CNS Diseases: ICV Administration as a Growing Standard for Delivery.
Intracerebroventricular administration involves delivering a therapeutic agent into the brain’s ventricular system, which contains cerebrospinal fluid. This route can be used to introduce treatments into the CNS and is being investigated for therapies targeting neurological diseases.
Delivering gene therapies to the CNS presents distinct challenges. Therapeutic vectors must reach relevant tissues and cells, and the selected route of administration can influence how the treatment is distributed throughout the brain and other parts of the nervous system.
ICV administration is an established neurosurgical procedure and provides a direct route into the cerebrospinal fluid. For certain CNS-directed therapies, this approach may offer advantages compared with administration routes that depend on the therapeutic agent crossing biological barriers to reach the target tissue.
The choice of delivery method, however, depends on the specific treatment, its vector characteristics, the intended target cells and the distribution required to achieve the desired therapeutic effect. Administration procedures also involve clinical considerations that must be evaluated for each therapeutic program.
Neurogene’s presentation will discuss ICV administration as part of the evolving landscape of CNS gene therapy delivery. The company describes this approach as a deliberate strategy intended to maximize efficacy for central nervous system gene therapies.
The presentation will provide a broader context for understanding the delivery strategy supporting programs such as NGN-401 and the practical considerations involved in administering genetic medicines to the CNS.
Presentation Schedule at ESGCT 2026
Neurogene will present its research during three sessions across October 28 and 29.
Wednesday, October 28, 2026
11:00–11:30 a.m. Central European Time (CET)
Invited talk — CNS & Sensory I Session
Self-regulating gene therapy for Rett syndrome
1:30–3:30 p.m. CET
Poster presentations
- Myth versus measurement: direct CNS comparison of two miRNA based regulated gene therapies in a mosaic model of Rett syndrome
- Gene Therapy Targeting CNS Diseases: ICV Administration as a Growing Standard for DeliveryThursday, October 29, 20262:00–4:00 p.m. CETPoster presentation
- Expression Kinetics and Clinical Onset of Benefit Following Single-Stranded AAV Delivery of NGN-401 in Rett Syndrome
The congress itself will run from October 27 through October 30 in Hamburg, Germany. Neurogene’s participation will bring together research on gene expression kinetics, regulatory technology and delivery approaches within a program focused on the development of genetic medicines for neurological disease.
Advancing NGN-401 Development for Rett Syndrome
The planned presentations reflect Neurogene’s efforts to address several interrelated challenges in Rett syndrome gene therapy: delivering therapeutic genetic material to the CNS, achieving timely transgene expression and maintaining appropriate levels of MECP2 expression across individual cells.
The preclinical comparison of miRNA-based regulation strategies may provide additional insight into the potential role of the EXACT platform, while the expression kinetics research will examine the relationship between single-stranded AAV delivery and the timing of observed clinical benefit.
The ICV administration presentation will complement these findings by addressing the delivery considerations involved in bringing gene therapies to the CNS.
Although the new research may help inform future development decisions, the preclinical findings and early clinical observations will need to be interpreted within the limitations of the available evidence. Continued clinical evaluation will be necessary to establish NGN-401’s safety, efficacy, durability of response and overall benefit-risk profile.
Through its presentations at the ESGCT 33rd Annual Congress, Neurogene aims to share additional scientific insights into its approach to gene therapy for Rett syndrome and contribute to broader discussions about the design of genetic medicines for rare neurological diseases.
About Neurogene
Neurogene (NASDAQ: NGNE) is a clinical-stage biotechnology company focused on developing life-changing genetic medicines for people and their families impacted by devastating neurological diseases. The Company is using a biology-first approach paired with optimized delivery to develop purpose-built genetic medicines, including programs powered by its novel and proprietary EXACT™ transgene regulation technology. Neurogene is advancing its lead gene therapy program, NGN-401, as a potential best-in-class, one-time treatment for Rett syndrome. For more information, visit neurogene.com or follow on LinkedIn.
About NGN-401
NGN-401 is an investigational AAV9 gene therapy in late-stage clinical development as a potential best-in-class, one-time treatment for Rett syndrome. It is the only clinical candidate to deliver the full-length human MECP2 gene and includes Neurogene’s EXACT™ transgene regulation technology, which is designed to deliver consistent, tightly controlled MeCP2 protein expression on a cell-by-cell basis. NGN-401 is delivered through intracerebroventricular administration to achieve the broadest targeting directly to the brain and nervous system based on nonclinical biodistribution data.
NGN-401 is being evaluated in the Embolden™ registrational clinical trial. Data from the Phase 1/2 trial (as of June 16, 2026) have shown that participants experienced multidomain, durable gains with continued developmental milestone acquisition observed over time, and NGN-401 at the 1E15 vg dose has been generally well-tolerated.
NGN-401 has received Breakthrough Therapy, Regenerative Medicine Advanced Therapy, Fast Track, Orphan Drug and Rare Pediatric Disease designations and selection for the START Pilot Program from the U.S. Food and Drug Administration, Advanced Therapy Medicinal Product, Orphan and Priority Medicines designations from the European Medicines Agency and Innovative Licensing and Application Pathway designation from the United Kingdom Medicines and Healthcare products Regulatory Agency.