Apertura Gene Therapy and Rett Syndrome Research Trust Collaborate to Pioneer Advanced Genetic Medicines for Rett Syndrome Using TfR1-Targeted AAV Capsid

New York, NY and Trumbull, CT, April 30, 2025 – Apertura Gene Therapy, a biotechnology company focused on innovative gene therapy solutions, and the Rett Syndrome Research Trust (RSRT), an organization working to cure Rett Syndrome, today announced a collaboration to license Apertura’s human transferrin receptor 1 capsid (TfR1 CapX). This partnership aims to advance innovative genetic medicine approaches for the treatment of Rett Syndrome, a rare genetic neurological disorder caused by random mutations in the MECP2 gene on the X chromosome that primarily affect females, causing developmental regression and severe motor and language impairments.

Apertura’s TfR1 CapX is an intravenously delivered adeno-associated virus (AAV) capsid engineered to bind the transferrin receptor 1 (TfR1), enabling efficient delivery of genetic medicines across the blood-brain barrier (BBB). TfR1 is a well-characterized BBB-crossing receptor, broadly and consistently expressed throughout life — even in the context of neurological disease — making it an attractive target for CNS delivery in disorders like Rett syndrome. Developed by Apertura’s academic founder, Dr. Ben Deverman, Director of Vector Engineering at the Broad Institute, TfR1 CapX has shown strong CNS selectivity in preclinical studies, achieving over 50% neuronal and 90% astrocyte transduction across multiple brain regions. Because Rett syndrome affects the brain diffusely, broader cellular transduction may correlate with greater symptomatic improvement.

“Efficient, safe, and widespread delivery of genetic medicines to the brain is the ultimate goal for treating CNS disorders such as Rett syndrome. Successfully addressing this challenge would dramatically accelerate the development of genetic medicines for Rett and other neurological diseases. My colleagues and I have extensively evaluated advanced delivery technologies, and Apertura’s capsid stands out for its impressive CNS biodistribution capabilities,” said Monica Coenraads, Founder and CEO of RSRT and parent to an adult daughter with Rett. “We’re enthusiastic about integrating this innovative capsid into our internal gene-editing programs and facilitating its adoption for external Rett syndrome programs as well. This collaboration represents a major step forward for patients.”

Last year RSRT launched the MECP2 Editing Consortium, a collaboration among six labs, developing next-generation genetic medicines for Rett syndrome. The Consortium’s editing programs will be utilizing the Apertura capsid to deliver genetic medicine cargoes diffusely across the brain non-invasively. Furthermore, the license allows RSRT to sublicense the capsid for Rett programs.

“RSRT has made remarkable progress in advancing Rett syndrome therapies, and Apertura is committed to accelerating this momentum with TfR1 CapX. Our engineered capsid addresses the critical need for more potent and less invasive treatments, significantly benefiting patients and caregivers. This collaboration reflects the innovative efforts of both organizations and serves as a pioneering example of how industry partnerships can rapidly advance vital therapies for patients in need,” said Diego Garzón, PhD, Vice President of Corporate Development, Apertura Gene Therapy. “Apertura’s TfR1 capsid has the potential to transform treatments for CNS diseases. We are committed to partnering with both for-profit and non-profit organizations to maximize this innovation's impact for patients.”