DALLAS, Texas — Taysha Gene Therapies, Inc. (Nasdaq: TSHA) (Taysha or the Company), a clinical-stage biotechnology company focused on advancing adeno-associated virus (AAV)-based gene therapies for severe monogenic diseases of the central nervous system (CNS), today announced that it will present new preclinical in vitro data from a head-to-head evaluation of TSHA-102 (scAAV9-miniMeCP2) compared to an analogous ssAAV9 construct with the full-length MECP2 in neuronal cell models. The data will be presented during a poster presentation at the upcoming American Society of Gene and Cell Therapy (ASGCT) Annual Meeting, taking place in Boston from May 11-15, 2026.
TSHA-102 is a scAAV9 gene therapy in clinical evaluation for Rett syndrome that encodes a functional, miniaturized MECP2 transgene, a key design feature that supports enhanced transduction efficiency and stability. Data to be presented are consistent with previously published vector comparisons demonstrating that scAAV9 drives significantly higher MeCP2 protein expression than ssAAV9, which support Taysha’s ability to effectively deliver TSHA-102 to the CNS using a minimally invasive lumbar intrathecal (IT) administration. In addition, the data show that the miniMeCP2 protein is functionally comparable to full-length MeCP2 protein across molecular and biochemical functions and exhibits comparable, stable expression in neuronal cells.
“These findings demonstrate that miniMeCP2 protein is functionally comparable to full-length MeCP2 and that the scAAV9 vector enables significantly higher protein expression, delivering up to 30-fold higher MeCP2 than a comparable ssAAV9 construct in neuronal cell models,” said Sukumar Nagendran, M.D., President and Head of Research & Development at Taysha. “The enhanced transduction efficiency and improved genomic stability of scAAV9 supports our ability to effectively deliver TSHA-102 to the CNS using a minimally invasive lumbar intrathecal administration. Importantly, the data provide direct mechanistic validation of TSHA-102’s differentiated construct design and offer translational support for the early, sustained and deepening functional gains demonstrated following treatment with TSHA-102 in Part A of our REVEAL Phase 1/2 trials. We look forward to reporting longer-term safety and efficacy data from our Part A of REVEAL Phase 1/2 trials later this quarter.”
Poster presentation details are as follows:
Title: Superior expression of self-complementary AAV and comparable functionality of mini and full-length MECP2 support the design of TSHA-102 gene therapy for Rett syndrome
Presenter: Ryan Chaparian, Principal Scientist, Bioanalytics, at Taysha Gene Therapies
Poster Session Date and Time: Thursday, May 14 from 5:00-6:30 PM ET
Session: Poster Reception
Poster Number: 3481
Additional details on the meeting can be found at the ASGCT Annual Meeting website.
About TSHA-102
TSHA-102 is a self-complementary intrathecally delivered AAV9 investigational gene transfer therapy in clinical evaluation for Rett syndrome. Designed as a one-time treatment, TSHA-102 aims to address the genetic root cause of the disease by delivering a functional form of MECP2 to cells in the CNS. TSHA-102 utilizes a novel miRNA-Responsive Auto-Regulatory Element (miRARE) technology designed to mediate levels of MECP2 in the CNS on a cell-by-cell basis without risk of overexpression. TSHA-102 has received Breakthrough Therapy, Regenerative Medicine Advanced Therapy, Fast Track and Orphan Drug and Rare Pediatric Disease designations from the FDA, Orphan Drug designation from the European Commission and Innovative Licensing and Access Pathway designation from the Medicines and Healthcare products Regulatory Agency.
About Rett Syndrome
Rett syndrome is a rare neurodevelopmental disorder caused by mutations in the X-linked MECP2 gene encoding methyl CpG-binding protein 2 (MeCP2), which is essential for regulating neuronal and synaptic function in the brain. The disorder is characterized by loss of communication and hand function, slowing and/or regression of development, motor and respiratory impairment, seizures, intellectual disabilities and shortened life expectancy. Rett syndrome progression is divided into four key stages, beginning with early onset stagnation at 6 to 18 months of age followed by rapid regression, plateau and late motor deterioration. Rett syndrome primarily occurs in females and is one of the most common genetic causes of severe intellectual disability. Currently, there are no approved disease-modifying therapies that treat the genetic root cause of the disease. Rett syndrome caused by a pathogenic/likely pathogenic MECP2 mutation is estimated to affect between 15,000 and 20,000 patients in the U.S., EU, and U.K.
About Taysha Gene Therapies
Taysha Gene Therapies (Nasdaq: TSHA) is a clinical-stage biotechnology company focused on advancing adeno-associated virus (AAV)-based gene therapies for severe monogenic diseases of the central nervous system. Its lead clinical program TSHA-102 is in development for Rett syndrome, a rare neurodevelopmental disorder with no approved disease-modifying therapies that address the genetic root cause of the disease. With a singular focus on developing transformative medicines, Taysha aims to address severe unmet medical needs and dramatically improve the lives of patients and their caregivers. The Company’s management team has proven experience in gene therapy development and commercialization. Taysha leverages this experience, its manufacturing process and a clinically and commercially proven AAV9 capsid in an effort to rapidly translate treatments from bench to bedside. For more information, please visit www.tayshagtx.com.
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