Unlocking the Brain: New Partnership Targets Gene Editing for Rett Syndrome

OXFORD, England – February 26, 2026 – In a move that could represent a significant leap forward for genetic medicine, biotechnology firm Evox Therapeutics has announced a partnership with the Rett Syndrome Research Trust (RSRT). The collaboration aims to tackle one of the most formidable challenges in modern medicine: safely delivering gene-editing tools to the brain to correct the root cause of Rett syndrome, a severe and debilitating neurodevelopmental disorder.

The partnership will evaluate Evox's proprietary ExoEdit® platform, which uses engineered exosomes—tiny, naturally occurring vesicles—as a delivery vehicle. If successful, the technology could unlock a new therapeutic pathway not only for Rett syndrome but for a host of other currently intractable neurological diseases.

“Gene editing offers the possibility of correcting the mutations responsible for Rett syndrome and potentially reversing symptoms even after disease onset, though safe and efficient delivery to the central nervous system remains a key challenge,” said Per Lundin, PhD, Co-founder and Chief Executive Officer of Evox.

The 'Trojan Horse' for Brain Therapy

For decades, the blood-brain barrier (BBB) has stood as medicine's great wall, a highly selective membrane that protects the brain from toxins and pathogens but also blocks the vast majority of therapeutic drugs. This biological fortress has been a primary obstacle for developing treatments for conditions like Alzheimer's, Huntington's, and Rett syndrome.

While viral vectors, particularly adeno-associated viruses (AAVs), have shown promise in clinical trials by ferrying genetic material into the brain, they are not without risks. These include the potential for triggering an immune response and the theoretical risk of integrating with the host's genome, which has prompted caution, especially with higher doses.

Evox Therapeutics is pioneering a different approach. Its ExoEdit® platform harnesses exosomes, which cells naturally use to communicate with each other by transporting proteins and nucleic acids. Crucially, these nanoparticles possess an innate ability to cross the BBB. Evox engineers these exosomes to carry specific therapeutic cargo, effectively turning them into a biological 'Trojan horse' that can deliver its payload directly to brain cells.

Compared to viral vectors, this non-viral method promises lower immunogenicity and avoids the risks associated with viral DNA. The technology offers a versatile platform capable of carrying diverse payloads, from RNA molecules to the complex machinery of CRISPR-based gene editing systems. This versatility is central to the new collaboration's goal: to precisely edit the mutated gene responsible for Rett syndrome.

A New Chapter for Rett Syndrome

Rett syndrome is a profound genetic disorder that primarily affects girls, typically becoming apparent between 12 to 18 months of age. Caused in over 90% of cases by mutations in the MECP2 gene, it leads to a devastating regression of skills. Children lose purposeful hand use and speech, and often their ability to walk. The condition requires lifelong, intensive care to manage a wide array of symptoms including seizures, breathing difficulties, and gastrointestinal issues.

The current treatment landscape is limited. In 2023, the FDA approved Daybue (trofinetide), the first-ever drug specifically for Rett syndrome. While it can improve some symptoms, it is not a cure. The ultimate goal for researchers and families is to correct the underlying genetic defect.

This is complicated by the 'Goldilocks problem' of the MECP2 gene. Both too little and too much of the MeCP2 protein it produces are toxic to neurons. Gene replacement therapies currently in clinical trials, which use AAVs to deliver a healthy copy of the gene, must carefully control expression levels to avoid harm. Gene editing, by contrast, offers the potential to repair the patient's own gene, allowing the cell's natural mechanisms to regulate protein levels, thereby elegantly solving the Goldilocks dilemma.

This is where the Rett Syndrome Research Trust plays a pivotal role. As the world's largest funder of Rett research, RSRT has been the driving force behind the current wave of genetic medicine trials. Their $40 million 'Roadmap to Cures' initiative aims to bring three new genetic medicines to clinical trial by 2028, exploring every promising avenue from gene therapy to RNA editing.

“Non-viral delivery to the brain has long been a major obstacle to establishing gene editing as a therapy for Rett syndrome. We see great potential in Evox's ExoEdit® technology to efficiently and safely deliver editing cargo throughout the brain,” said Monica Coenraads, Founder and CEO of RSRT and the parent of an adult daughter with the condition. “My colleagues and I are enthusiastic about this study and look forward to seeing the results, which may open the door to a new clinical pathway for Rett patients.”

Navigating a High-Stakes Therapeutic Frontier

The partnership places Evox in the center of one of biotechnology's most competitive and valuable fields. The market for gene therapies targeting central nervous system disorders is projected to grow exponentially, potentially reaching over $190 billion by 2035. Companies like Taysha Gene Therapies and Neurogene are already in clinical trials with AAV-based gene replacement therapies for Rett syndrome, research that RSRT itself helped fund.

Evox’s collaboration with RSRT is a strategic validation of its non-viral, gene-editing approach. By targeting the root cause with precision, the ExoEdit® platform represents a potential next-generation therapy that could offer advantages over existing methods. Success in a complex indication like Rett syndrome would serve as powerful proof-of-concept for the platform's broader applicability in other neurodegenerative diseases, from Huntington's to ALS, which are already part of Evox's pipeline.

This initial feasibility study is the first step. If the findings are positive, it will lay the foundation for an expanded preclinical program with the ultimate goal of developing a curative therapy for the vast majority of individuals living with Rett syndrome.

The Long Road from Lab to Life

While the promise of exosome-based delivery is immense, experts caution that the path to clinical reality is long and fraught with challenges. The scientific community widely acknowledges the potential of exosomes to overcome the BBB, but significant hurdles remain. Key among them are developing processes for large-scale, GMP-compliant manufacturing to ensure consistency, purity, and safety.

Furthermore, regulatory agencies will require extensive data to establish the safety and efficacy of this novel therapeutic modality. The exact mechanisms of exosome transport and cargo release within the brain are still areas of active investigation, and optimizing targeting efficiency remains a critical goal.

Despite these challenges, the collaboration between a pioneering biotech company and a deeply committed patient advocacy organization represents a powerful synergy. It combines cutting-edge science with the urgent, personal drive for a cure. If this venture succeeds in demonstrating that engineered exosomes can safely and effectively edit genes in the brain, it will not just offer hope to the Rett syndrome community—it will mark the dawn of a new era in treating genetic diseases of the nervous system.