Neurogene (NASDAQ:NGNE) CEO and founder Rachel McMinn outlined the company’s progress toward a potential commercial launch for its lead gene therapy candidate, NGN-401, during a fireside chat focused on Rett syndrome, regulatory alignment, trial design, and upcoming catalysts.
Company focus and lead program
McMinn described Neurogene as a genetic medicines company developing treatments for “devastating neurological diseases” using what she called a “biology-first design approach.” The company’s lead program, NGN-401, targets Rett syndrome, which she characterized as a disorder in which children lose independence and require lifelong caregiver support for basic functions.
Phase III registrational trial and near-term milestones
McMinn said Neurogene’s Phase III registrational trial, Embolden, is enrolling females with classic Rett syndrome who are age three and older and have completed the regression phase of the disease. She stated the trial is actively enrolling and dosing patients and that the company “remain[s] on track to complete dosing in the second quarter of this year.”
She also pointed to several catalysts the company expects this year, including:
- Completion of dosing in the Embolden trial in the second quarter of this year
- Additional Phase I/II data expected mid-year, including “a minimum of 12 months of follow-up on all participants”
McMinn said she views completion of dosing as an important investor milestone, in part because it could provide a read-through on safety concerns that have been discussed in the market.
FDA interactions and trial design
In response to questions about the current narrative around FDA flexibility in rare disease, McMinn said Neurogene continues to believe that the FDA and industry are aligned on accelerating rare disease treatments to patients. She highlighted that Neurogene participates in the START Pilot program, which she said provides an “unprecedented level of access” to the agency compared with other programs.
McMinn said Embolden was designed in close collaboration with the FDA over multiple meetings and across multiple administrations. She added that before dosing the first Embolden patient, the company went back to the agency “as recently as this fall” and received written confirmation that key elements of the trial design were acceptable. She noted that, following discussions with the FDA, the company also added efficacy measures that it might not have included otherwise.
She emphasized that the study is open-label and baseline-controlled, but she described the endpoint approach as consistent with a traditional approval pathway based on gain of function rather than a surrogate endpoint or biomarker. McMinn said the 12-month follow-up duration aligns with FDA written feedback supporting that period as clinically meaningful.
Asked about the seniority of FDA engagement and potential leadership changes at the Center for Biologics Evaluation and Research (CBER), McMinn said the company’s review team has not “fundamentally changed across administrations.” She also said she serves on the board of the Alliance for Regenerative Medicine (ARM), which she described as engaging with the FDA and stakeholders to foster alignment, and noted that she sees reason for optimism based on public statements supporting expedited rare disease product development.
Phase I/II data: milestones gained and durability
McMinn summarized previously presented Phase I/II efficacy data from eight pediatric participants, saying they represented a “full spectrum” of disease severity. She said all treated patients showed functional improvement in one or more Rett syndrome core domains, including hand function, gross motor function, and communication.
Across the dataset, she said there were 25 total developmental milestones gained—about four per participant on average—and described those gains as durable and accumulating over time with “no sign of plateau.” She also stated that 88% of participants achieved an improvement on the CGI-I (Clinician Global Impression of Improvement) score. At the 1E15 dose, McMinn said NGN-401 was “generally well-tolerated.”
Addressing skepticism about open-label datasets and the subjectivity of developmental endpoints, McMinn pointed to the NIH-sponsored Rett Syndrome Natural History Study and clinician experience, stating it is “extraordinarily rare” for patients past the regression phase to gain new milestones spontaneously. She also linked the clinical observations to biological rationale, saying MECP2 is critical to neuronal health throughout life and that restoring MECP2 would be expected to improve synaptic function over time.
McMinn provided an example of a patient with two years of follow-up, describing baseline limitations in grasping, stair climbing, and meaningful communication. She said that 24 months after treatment, the patient showed more purposeful hand use (including feeding herself with a fork), improved mobility (including going up and down stairs unassisted), and increased ability to follow instructions and participate in daily routines.
Safety discussion and pivotal trial success threshold
On safety, McMinn referenced a prior “hyper-inflammatory reaction” observed at a dose three times higher than the current dose, which she said was discontinued due to an uncontrolled immune response from a large amount of AAV in systemic circulation. She said Neurogene implemented robust monitoring and a treatment plan in the protocol, and stated that if HLH were detected early in an AAV setting, it has been shown to be “fully reversible” with high-dose steroids or anakinra.
Regarding ongoing experience, she said, “no news is good news,” adding that the company has not seen any cases of HLH or other severe inflammatory reactions to date.
McMinn also described the statistical framework for Embolden. She said Neurogene established a 35% threshold for success based on analysis of natural history data aligned with Embolden eligibility criteria, and focused on a pre-specified set of clinically meaningful milestones with low spontaneous acquisition. She said that under this framework, seven out of 20 participants would need to be responders to achieve statistical success.
On commercial expectations, McMinn said families want to see more than one skill gain and want continued improvement over time. She cited what she called an 80% response rate based on the first five patients at 12 months as “very compelling,” and said the company will continue monitoring durability and long-term gain of function.
McMinn also addressed competitive dynamics and Neurogene’s approach, saying NGN-401 was designed for intracerebroventricular (ICV) administration because Rett is a CNS-mediated disease and because, based on preclinical biodistribution and other labs’ work, ICV may better reach key brain regions than intrathecal lumbar delivery. She said the procedure is common and takes about an hour, and argued that the one-time procedure should be considered in the context of one-time gene therapy, followed by ongoing safety monitoring consistent across gene therapies regardless of administration route.
Finally, McMinn said Neurogene’s capital provides runway through the first quarter of 2028, which she said should be sufficient to fund clinical and regulatory milestones including Embolden results, BLA submission, and pre-launch activities.
About Neurogene (NASDAQ:NGNE)
Neurogene, Inc is a clinical‐stage biotechnology company specializing in the development of gene therapies for rare neurological diseases. The company’s lead platform employs adeno‐associated virus (AAV) vectors designed to deliver functional copies of disease-causing genes directly to the central nervous system. Neurogene’s pipeline focuses on inherited lysosomal storage disorders, including investigational programs for GM1 and GM2 gangliosidoses, with additional preclinical efforts targeting other monogenic neurodegenerative conditions.
Neurogene’s proprietary AAV9‐based delivery system has been engineered to cross the blood-brain barrier, aiming to provide durable gene expression in affected tissues.
