A patient taking part in Neurogene’s Rett syndrome trial has died following complications from a rare hyperinflammatory syndrome. Credit: Shutterstock / romakhan3595.

A patient taking part in Neurogene’s Rett syndrome trial has died following complications from a rare hyperinflammatory syndrome associated with adeno-associated virus (AAV) based therapies.

A 20 November report filed with the US Securities and Exchange Commission (SEC) disclosed that the patient was dosed in the Phase I/II trial (NCT05898620) on 5 November with 3E15 vg of NGN-401. Earlier this week, the patient was reported to be in critical condition but has since died following complications from a rare and life-threatening hyperinflammatory syndrome associated with exposure to high doses of AAV.

Go deeper with GlobalData

Data Insights

The gold standard of business intelligence.

Find out more

“The FDA allowed Neurogene to proceed with the Phase I/II trial using the 1E15 vg dose for both the pediatric and adolescent/adult cohorts. Neurogene will also incorporate the 1E15 vg dose in its future registrational trial design planning,” the SEC document filing reads.

The news follows just over a week after the company initially announced the incident sending its stock price spiralling losing 34% in premarket value. Since the patient’s death, the company’s stock has continued to slump, sitting at $15.59 per share – a stark drop from its height of $71.53 before the initial announcement of the adverse event.

Before the patient’s death on 18 November, the company confirmed that it had paused further use of the 3E15 vg dose and does not plan to enrol any further participants on the 3E15 vg dose arm of the trial.

The company’s open-label trial (NCT05898620) aims to examine NGN-401, a gene therapy used in female paediatric patients living with Rett syndrome, a genetic disorder that typically becomes apparent after six to 18 months occurring more frequently in girls. It can lead to several developmental and health difficulties in early life.

How well do you really know your competitors?

Access the most comprehensive Company Profiles on the market, powered by GlobalData. Save hours of research. Gain competitive edge.

Company Profile – free sample

Thank you!

Your download email will arrive shortly

Not ready to buy yet? Download a free sample

We are confident about the unique quality of our Company Profiles. However, we want you to make the most beneficial decision for your business, so we offer a free sample that you can download by submitting the below form

By GlobalData
Visit our Privacy Policy for more information about our services, how we may use, process and share your personal data, including information of your rights in respect of your personal data and how you can unsubscribe from future marketing communications. Our services are intended for corporate subscribers and you warrant that the email address submitted is your corporate email address.

The investigational AAV9 gene therapy is being developed as a one-time treatment for Rett syndrome. It uses Neurogene’s EXACT transgene regulation technology to deliver the full-length human MECP2 gene.

In last week’s announcement, the company also said that the first four participants showed consistent, concordant improvements across key Rett syndrome scales, achieving the score of “much improved” on the Clinical Global Impression-Improvement (CGI-I) scale.

Speaking on 18 November, Neurogene founder Rachel McMinn said: “We have observed girls gaining complex skills rarely ever learned in this population, as well as skills that were once present and lost during the phase of developmental regression.

“We will continue to engage with the FDA on the planning for a future registrational clinical trial and anticipate providing an update on the trial design in the first half of 2025.”