Gene Therapy for Brain Diseases: Highlights from the 2026 ASGCT Annual Meeting
In mid-May, thousands of researchers, doctors, and biotech company representatives gathered in Boston for the annual meeting of the American Society of Gene and Cell Therapy (ASGCT) — the field's most important scientific conference of the year. Presentations spanned many disease areas, but brain and nervous system diseases were a standout theme. This reflects a simple reality: these conditions represent some of the greatest unmet needs in medicine today, and gene therapy is increasingly seen as one of the most promising paths forward.
A Landmark Moment for Dravet Syndrome
The conference's most prestigious slot — the Presidential Symposium — was dedicated to a clinical update on gene therapy for Dravet syndrome, a severe form of childhood epilepsy caused by a faulty copy of a gene called SCN1A. This is similar in principle to what happens in Phelan-McDermid syndrome (PMS), where a missing or non-working copy of the SHANK3 gene disrupts normal brain development.
Researchers presented one-year results from 21 young children who received a one-time gene therapy designed to supply a working copy of SCN1A directly to the brain. The results were striking: seizures decreased significantly, and perhaps even more encouragingly, children showed measurable gains in cognition and began following a more typical developmental path. The therapy was also found to be safe. On the strength of these results, the company has now launched a pivotal clinical trial — the final step before seeking FDA approval to make the therapy broadly available.
Progress for Other Neurodevelopmental Diseases
Dravet syndrome was not alone in the spotlight. Researchers also presented promising clinical updates for gene therapies targeting Rett syndrome and Angelman syndrome — two other conditions that, like PMS, are associated with intellectual disability, limited speech, and features of autism. All three programs reflect a broader wave of gene therapies moving from the laboratory into real patients, with encouraging early results.
What's Next: Smarter, Simpler Delivery
While these "first-generation" gene therapies have made remarkable progress — including Jaguar Gene Therapy's SHANK3 clinical program for PMS— scientists have not stood still. A major theme at this year's meeting was again the development of next-generation delivery vehicles.
Current gene therapies for brain diseases are typically delivered through a direct injection into the brain or spinal fluid, which requires a surgical procedure. Researchers are now engineering new versions of the AAV gene therapy delivery vehicle that can be given through a simple intravenous (IV) infusion, like a standard drip. These redesigned vectors have been engineered to cross the blood-brain barrier, a protective shield around the brain. Studies in monkeys and other large animals show these next-generation vectors can reach far more brain cells than current approaches. Clinical testing for many of those novel vectors is still pending but there is a promise to make gene therapy more efficacious with the added benefit of increased safety.
Making Gene Therapy More Affordable
Another prominent topic was the cost of manufacturing gene therapies — currently one of the biggest barriers to getting these treatments to patients. Multiple companies presented innovative approaches to driving down production costs, ranging from improvements to traditional manufacturing systems to genuinely novel ideas, such as using specially modified tobacco plants as a low-cost way to produce gene therapy ingredients at scale. Lowering costs is not just a business concern — it directly affects whether patients can access these therapies at all.
The Regulatory Challenge
Despite the scientific excitement, a significant and recurring frustration was raised throughout the conference: the regulatory path to approval remains extremely difficult, particularly for rare diseases. Several speakers noted that some gene therapies with proven benefit in patients have been stuck in clinical limbo for years — not because of safety concerns, but because the cost and complexity of meeting FDA manufacturing requirements is simply beyond the reach of smaller rare disease programs. As one speaker put it, gene therapy doses to treat a few dozen patients per year are held to the same manufacturing standards as a drug produced by the millions. Many in the field are calling on the FDA to develop a more proportionate, disease-specific regulatory framework — one that maintains rigorous safety standards while recognizing the unique realities of rare disease gene therapy. For rare disease communities like PMS, where every year of delay means another year without treatment, this is not an abstract policy debate. It is personal.
Ralf Schmid is the Chief Scientific Officer (CSO) at CureSHANK and can be reached at research@cureshank.org
