Letter to our Rett Syndrome Community
Dear Rett Syndrome Community,
Today Neurogene announced that the U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy designation for NGN-401, our investigational gene therapy for Rett syndrome. We are writing this letter to provide further context as to what this means.
What is Breakthrough Therapy designation?
- Breakthrough Therapy designation is meant to help speed the development and regulatory review of medicines, including gene therapies, that are being researched to treat serious conditions, such as Rett syndrome.
- To obtain this designation from the FDA, the investigational gene therapy must show early evidence in human trials that indicate there is a potential to have a substantial, meaningful improvement in outcomes that are significant and better than treatments that are already available.
What is the benefit of Breakthrough Therapy designation?
- Obtaining the Breakthrough Therapy designation makes the investigational medicine eligible for mechanisms at the FDA that are intended to help speed drug development as part of the Agency’s commitment to help find an efficient route to marketing approval.
- This includes eligibility for Priority Review, which shortens the review time for a biologics license application, and the ability to have a rolling submission for portions of the application, allowing for earlier evaluation.
What data did FDA base their decision on to grant Breakthrough Therapy designation?
- The FDA based their decision on the interim results of the Phase 1/2 clinical trial of NGN-401 from October 30, 2025, which we reported in November 2025, in girls with Rett syndrome.
- A summary of these results is available at this LINK
Where can more information about Breakthrough Therapy designation be found?
- You can read more on FDA’s website at this LINK
What other regulatory designations does NGN-401 already have in the US?
- Regenerative Medicine Advanced Therapy (RMAT) designation
- Learn more about RMAT at this LINK
- Orphan Drug designation
- Fast Track designation
- Rare Pediatric designation
- NGN-401 was also one of the few investigational medicines selected for FDA’s Support for Clinical Trials Advancing Rare Disease Therapeutics (START) Pilot Program
- Learn more about START at this LINK
What regulatory designations have been made in Europe and the United Kingdom?
- In Europe, NGN-401 received:
- Priority Medicines (PRIME) designation
- More information at this LINK
- Priority Medicines (PRIME) designation
- Orphan designation
- Advanced therapy medicinal product (ATMP) designation from the European Medicines Agency (EMA)
- More information at this LINK
- In the United Kingdom, NGN-401 received:
- Innovative Licensing and Application Pathway (ILAP) designation from the United Kingdom (UK) Medicines and Healthcare products Regulatory Agency (MHRA)
- More information may be found at this LINK
- Innovative Licensing and Application Pathway (ILAP) designation from the United Kingdom (UK) Medicines and Healthcare products Regulatory Agency (MHRA)
What is the status of Embolden™, the registrational clinical trial for NGN-401?
- Dosing of all participants in Embolden is on track to be completed in the second quarter of this year.
How can Neurogene be contacted?
- Patients and families can reach us at: [email protected]
- Healthcare providers can reach us at: [email protected]
- General inquiries by phone: +1-877-237-5020
- Neurogene is on Facebook, LinkedIn and X
Sincerely,
Kimberly Trant, RN, MBA
Executive Director, Patient Advocacy and Engagement
Background on NGN-401
NGN-401 is an investigational gene therapy that Neurogene is developing as a potential one-time treatment for Rett syndrome. Rett syndrome is caused by variants in the MECP2 gene and NGN-401 is designed to deliver functional copies of the full-length human MECP2 gene (also known as a transgene). NGN-401 is delivered by a common neurosurgical procedure called intracerebroventricular (ICV) administration, which has been shown in preclinical studies to deliver gene therapy to the key areas of the brain and nervous system underlying Rett syndrome. NGN-401 uses Neurogene’s EXACT™ technology, which is designed to control MECP2 transgene expression to avoid overexpression toxicity.
Important Information
NGN-401 is not approved by any regulatory agency for use outside of the clinical trial.
Estimates for future events, such as the completion of dosing in the Embolden clinical trial and expectations for a streamlined application process with the FDA, are based on information currently available to Neurogene and are subject to change.
Rachel McMinn, Ph.D., is Chief Executive Officer of Neurogene and serves as Executive Chair of the company’s Board of Directors. She founded Neurogene in January 2018 with the mission of developing genetic medicines to improve the lives of neurologically-impaired people and their families. Prior to founding Neurogene, Dr. McMinn served as the Chief Business and Strategy Officer of Intercept Pharmaceuticals, a company dedicated to patients with serious liver disease. Prior to her industry experience, Dr. McMinn was an award-winning biotechnology analyst, with 13 years of experience at firms including Bank of America Merrill Lynch, Cowen, and Piper Jaffray. She graduated from Cornell University magna cum laude with a B.A. and earned her Ph.D. from The Scripps Research Institute and was awarded a Post-Doctoral Miller Fellowship at the University of California, Berkeley.
Christine Mikail, J.D., is President and Chief Financial Officer of Neurogene. In her role, Ms. Mikail leads Corporate Strategy and Business Development, Portfolio Management, Operations, and Finance. Ms. Mikail, who joined Neurogene in 2019, brings over two decades of experience supporting biotechnology and pharmaceutical companies in corporate strategy and business development, operations, legal and finance capacities. Prior to Neurogene, Ms. Mikail was Chief Administrative Officer and Head of External Business Development/Alliance Management and General Counsel at Axovant Sciences, Inc., where she was an integral member of the team that raised $362 million in the company’s IPO. Prior to joining Axovant, she held a variety of senior executive positions at NPS Pharmaceuticals, Inc., Dendreon Corporation, Eli Lilly and Company, and ImClone Systems. Ms. Mikail developed her life sciences focus as a corporate and securities lawyer at Reed Smith and WilmerHale. Ms. Mikail graduated cum laude with a B.A. from Rutgers University and earned her J.D. from Fordham University School of Law in 
Andrew Mulberg, M.D., serves as Senior Vice President, Regulatory Affairs, Quality Assurance, and Quality Control at Neurogene. Dr. Mulberg is a pediatric gastroenterologist with nearly 30 years of experience and has a strong passion for helping bring important new medicines to market for patients with devastating rare diseases. In his role at Neurogene, he provides strategic leadership and direction for regulatory and quality activities. Prior to joining Neurogene, Dr. Mulberg led global regulatory affairs for Amicus Therapeutics and held various roles of increasing responsibility within global drug development and medical affairs at Johnson & Johnson. In addition to Dr. Mulberg’s biotechnology and pharmaceutical experience, he spent six years as the Division Deputy Director in the Division of Gastroenterology and Inborn Errors Products at the U.S. FDA. He received his B.A. from Columbia University and his M.D. from Mount Sinai School of Medicine. Dr. Mulberg also previously served as Attending Physician and Fellowship Director of Gastroenterology and Hepatology at Children’s Hospital of Philadelphia. He is currently an adjunct Professor of Pediatrics at the University of Maryland Medical Center, and Chairman of the Medical Advisory Board Go4 the Goal foundation, a pediatric cancer advocacy 501(c)(3) organization.
Stuart Cobb, Ph.D., is Chief Scientific Officer at Neurogene. Dr. Cobb, who joined Neurogene in 2019, brings to the team more than 20 years of experience in translational neuroscience. He leads Neurogene’s scientific research, the development of scientific strategy to support the company’s existing and growing gene therapy portfolio, and efforts to identify novel technologies that complement Neurogene’s pipeline. In addition to his role at Neurogene, Dr. Cobb also leads a research team at the University of Edinburgh, where he is Professor of Translational Neuroscience at Simons Initiative in the Developing Brain and Centre for Discovery Brain Sciences. Prior to his work at Neurogene, Dr. Cobb was a Caledonian Research Fellow and led an academic research laboratory at the University of Glasgow. His research has focused on developing novel genetic treatments for brain disorders based on a deep understanding of the molecular and cellular pathology. Dr. Cobb’s work has been published in leading journals and includes seminal work on the inherent reversibility of neurological features in neurodevelopmental disease. Dr. Cobb has a B.Sc. from the University of Glasgow and a Ph.D. in Neuroscience from the University of Oxford.
Donna M. Cochener, J.D., LL.M., is Senior Vice President and General Counsel of Neurogene. She is a seasoned legal and executive professional with over two decades of experience in corporate law, governance, and executive leadership across the biotechnology and financial services sectors. Prior to joining Neurogene, Ms. Cochener held the roles of Interim Chief Executive Officer and General Counsel at Neoleukin Therapeutics, where she led the company through its merger with Neurogene in December 2023. Her earlier career includes serving as Senior Vice President and Deputy General Counsel at HomeStreet, Inc., the parent company of HomeStreet Bank, where she was primarily responsible for securities reporting and compliance, corporate governance, and led various transactions including mergers and acquisitions. Ms. Cochener was previously a partner at Davis Wright Tremaine LLP in Seattle, and also held associate positions at Heller Ehrman LLP, Riddell Williams P.S., and Perkins Coie LLP.
Julie Jordan, M.D., is Chief Medical Officer at Neurogene. Dr. Jordan brings over 20 years of industry and clinical expertise involving the design and execution of global clinical trials across multiple development areas, including gene therapy and central nervous system disorders. Before joining Neurogene, she was Chief Medical Officer at Homology Medicines, where she was responsible for leading clinical development and operations, leading regulatory interactions and supporting translational research programs for the company’s pipeline of gene therapy and gene editing candidates for rare diseases. She previously held global leadership roles of increasing responsibility at Cerevel Therapeutics, Avanir Pharmaceuticals and Teva Pharmaceutical Industries. Prior to her industry experience, Dr. Jordan was a practicing physician for 10 years and previously served as Clinical Instructor of Medicine at Harvard Medical School and in the Department of Medicine at Massachusetts General Hospital (MGH). She holds an A.B. in Biology from Harvard College and an M.D. from Harvard Medical School and completed her residency in Internal Medicine at MGH, Harvard Medical School.
Arvind Sreedharan serves as Senior Vice President, Business Operations at Neurogene. Mr. Sreedharan, who leads business operations at Neurogene, has over three decades of commercial experience in the pharmaceutical and biotechnology industry, including significant experience in CNS disorders and multiple orphan diseases. Prior to Neurogene, he served as Vice President, U.S. Commercial Operations for AveXis, the gene therapy company that developed Zolgensma®, an FDA-approved treatment for spinal muscular atrophy (SMA), which was acquired by Novartis for $8.7 billion. Earlier, Mr. Sreedharan served as Vice President of Marketing at Auspex Pharmaceuticals, a biopharmaceutical company focused on hyperkinetic movement disorders and rare diseases, acquired by Teva Pharmaceutical for $3.5 billion. Before Auspex, he served as Director, Movement Disorders at Lundbeck, where he played an integral commercial role in the successful product launch and management of Xenazine®, the first FDA-approved drug for the treatment of chorea associated with Huntington’s disease. Mr. Sreedharan has supported and partnered with numerous rare disease advocacy groups throughout his career. He previously served on the Huntington’s Disease Society of America Board of Trustees and is currently a member of the Board of Directors for The Huntington Study Group (HSG), the first Huntington’s Disease cooperative therapeutic research organization and a world leader in facilitating high-quality clinical research trials and studies in Huntington’s Disease. Mr. Sreedharan holds a B.A. in both Biology and History from the University of North Carolina.
Ricardo Jimenez serves as Senior Vice President, Technical Operations at Neurogene. Mr. Jimenez has nearly three decades of experience in the pharmaceutical and biotechnology industry, the majority of which has been focused in the gene therapy field. He joined Neurogene in 2018 and during his tenure has led the company’s internal build out of process and analytical development, the CGMP manufacturing facility including its design, manufacturing operations, quality assurance, and quality control supporting viral vector manufacturing from research grade to clinical scale. Prior to his work at Neurogene, Mr. Jimenez was the site head of the Lonza Houston manufacturing facility and played a leading role in establishing Lonza as a leading contract cell and gene therapy manufacturer, including designing and overseeing the construction of the cell and gene therapy facility in Texas. He began his career in gene therapy in 2005 at Introgen Therapeutics, where he was responsible for the validation activities for adenoviral-based products, and subsequently served as Head of Quality at Vivante GMP Solutions, a gene therapy contract manufacturing organization acquired by Lonza in 2010. Mr. Jimenez holds a B.S. in Biomedical Science from Texas A&M University.