Neurogene Announces Upcoming Presentations Highlighting Key Differentiators of NGN-401 for Rett Syndrome at the ESGCT 33rd Annual Congress

New presentations to highlight rapid transgene expression of full-length MECP2 following single-stranded AAV delivery and evaluation of miRNA-based approaches to regulating MeCP2 expression on a cell-by-cell basis

NEW YORK--(BUSINESS WIRE)--Neurogene Inc. (Nasdaq: NGNE), a clinical-stage company founded to bring life-changing genetic medicines to patients and families affected by rare neurological diseases, today announced that it will present data from its NGN-401 gene therapy program for Rett syndrome at the European Society of Gene and Cell Therapy (ESGCT) 33^rd Annual Congress, taking place October 27-30, 2026, in Hamburg, Germany.

New preclinical data to be featured are aimed at addressing two important questions in AAV gene therapy for Rett syndrome: how rapidly single-stranded AAV delivery translates into meaningful transgene expression and how different miRNA-based approaches regulate MECP2 transgene expression on a cell-by-cell basis. The presentations will include preclinical data characterizing expression kinetics following single-stranded AAV delivery alongside observations of early time-to-response in the NGN-401 Phase 1/2 trial. In addition, results from an in vivo evaluation of miRNA-based transgene regulation approaches, including the Company's EXACT™ transgene regulation technology, in a preclinical model of Rett syndrome will be shared. Additional presentations will focus on intracerebroventricular (ICV) administration as a well-established, routinely performed neurosurgical procedure and a deliberate delivery strategy designed to maximize efficacy for central nervous system gene therapies, as well as an overview of the EXACT platform.

The details of Neurogene’s presentations are as follows:

Wednesday, October 28

Invited Talk during CNS & Sensory I Session: 11:00 – 11:30 a.m. CET

• Self-regulating gene therapy for Rett syndrome

Poster Presentations: 1:30 – 3:30 p.m. CET

• 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 Delivery

Thursday, October 29

Poster Presentation: 2:00 – 4:00 p.m. CET

• Expression Kinetics and Clinical Onset of Benefit Following Single-Stranded AAV Delivery of NGN-401 in Rett Syndrome

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.

Cautionary Note Regarding Forward-Looking Statements
Statements in this press release are made as of the date of this press release. Neurogene does not undertake any obligation to make any updates to these statements to reflect events that occur or circumstances that arise after the date of this press release, except as may be required under applicable U.S. securities law.

Statements in this press release which are not historical in nature are intended to be, and hereby are identified as, forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These statements may discuss goals, intentions and expectations as to future plans, trends, events, results of operations or financial condition, or otherwise, based on current expectations and beliefs of the management of Neurogene, as well as assumptions made by, and information currently available to, management of Neurogene, including, but not limited to, statements regarding: the therapeutic potential and utility, efficacy and clinical benefits of NGN-401; the safety and tolerability profile of NGN-401; the applicability of reported interim results from the NGN-401 Phase 1/2 clinical trial to other participants; the potential for NGN-401 to be a best-in-class gene therapy for Rett syndrome; the potential for future approval for commercialization of NGN-401 as a treatment for Rett syndrome; the potential for success of the Embolden registrational clinical trial of NGN-401 for Rett syndrome; the clinical benefit of delivering NGN-401 via intracerebroventricular administration; the anticipated benefits of any regulatory designation for NGN-401, including the FDA’s Breakthrough Therapy designation, Rare Pediatric Disease designation, RMAT designation and participation in the FDA’s START Pilot Program; the content and timing of, and any conclusions that may be drawn from, the data to be presented at the ESGCT 33^rd Annual Congress; the expression kinetics and time to clinical response of NGN-401; and the potential advantages of the EXACT™ transgene regulation technology relative to other miRNA-based regulation technologies. Forward-looking statements generally include statements that are predictive in nature and depend upon or refer to future events or conditions, and include words such as “may,” “will,” “should,” “would,” “expect,” “anticipate,” “plan,” “likely,” “believe,” “estimate,” “project,” “intend,” “on track,” and other similar expressions or the negative or plural of these words, or other similar expressions that are predictions or indicate future events or prospects, although not all forward-looking statements contain these words. Forward-looking statements are based on current beliefs and assumptions that are subject to risks, uncertainties and assumptions that are difficult to predict with regard to timing, extent, likelihood, and degree of occurrence, which could cause actual results to differ materially from anticipated results and many of which are outside of Neurogene’s control. Such risks, uncertainties and assumptions include, among other things, those identified under the heading "Risk Factors" included in Neurogene’s Annual Report on Form 10-K for the year ended December 31, 2025, filed with the Securities and Exchange Commission (“SEC”) on March 24, 2026, the Quarterly Report on Form 10-Q for the quarter ended June 30, 2026, filed with the SEC on August 11, 2026, and other filings that the Company has made and may make with the SEC in the future. Nothing in this press release should be regarded as a representation by any person that the forward-looking statements set forth herein will be achieved or that the contemplated results of any such forward-looking statements will be achieved. Forward-looking statements in this press release speak only as of the day they are made and are qualified in their entirety by reference to the cautionary statements herein. Except as required by applicable law, Neurogene undertakes no obligation to revise or update any forward-looking statement, or to make any other forward-looking statements, whether as a result of new information, future events or otherwise.