Taysha Gene Therapies, Inc.

Taysha Gene Therapies, Inc. (NASDAQ: TSHA) is a clinical-stage biotechnology company focused on developing adeno-associated virus (AAV)-based gene therapies for severe monogenic diseases of the central nervous system. The company's lead clinical program, TSHA-102, is in development for the treatment of Rett syndrome, a rare neurodevelopmental disorder caused by mutations in the MECP2 gene that currently has no approved disease-modifying therapies addressing the genetic root cause.

TSHA-102 is designed as a one-time treatment delivered via intrathecal administration directly to the cerebrospinal fluid. The therapy incorporates the company's proprietary miRNA-Responsive Auto-Regulatory Element (miRARE) technology, which uses endogenous microRNA binding sites to prevent overexpression of the MECP2 protein and maintain safe transgene expression levels on a cell-by-cell basis. The estimated addressable patient population for Rett syndrome comprises between 15,000 and 20,000 patients across the United States, European Union, and United Kingdom.

The company is evaluating TSHA-102 through the REVEAL Phase 1/2 clinical trials, which include both adolescent/adult and pediatric studies conducted in the United States and Canada. As of the March 2026 data cutoff, twelve patients have been treated with no treatment-related serious adverse events or dose-limiting toxicities reported. Clinical data from May 2025 demonstrated that all ten evaluated patients gained or regained one or more developmental milestones across communication, fine motor, and gross motor function. The REVEAL pivotal trial (Part B) is designed to enroll fifteen females aged six to twenty-two years in the developmental plateau population, with a primary endpoint assessing response rate based on gaining or regaining at least one developmental milestone from a defined list of twenty-eight milestones.

Taysha has received multiple regulatory designations including orphan drug designation, rare pediatric disease designation, Fast Track Designation, Regenerative Medicine Advanced Therapy (RMAT) designation, and Breakthrough Therapy designation from the FDA. The company's pipeline includes early-stage programs for tauopathies (TSHA-113), Fragile X syndrome (TSHA-114), and previously discontinued programs. The company maintains license agreements with The University of Texas Southwestern Medical Center and Abeona Therapeutics for its gene therapy platform and specific indications.