Taysha’s TSHA-102 Received FDA Breakthrough Therapy Designation for Rett Syndrome
Taysha Gene Therapies has announced that the U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy designation to TSHA-102, an intrathecal AAV9 gene therapy for Rett syndrome.
The company also confirmed final alignment with the FDA on the REVEAL pivotal trial protocol and statistical analysis plan (SAP), supporting the planned Biologics License Application (BLA) submission.
The designation follows positive clinical data from Part A of the REVEAL Phase 1/2 trials in adolescents, adults, and paediatric patients, showing a generally well-tolerated safety profile and a 100% response rate for the primary endpoint of gain or regain of at least one defined developmental milestone.
Dose-dependent improvements were also observed in multiple outcome measures, including the Revised Motor Behavior Assessment (R-MBA) and Clinician Global Impression – Improvement (CGI-I).
The REVEAL pivotal trial is a single-arm, open-label study of 15 females aged 6 to under 22 years, receiving a single high-dose intrathecal administration of TSHA-102 (1x10¹⁵ vector genomes).
The primary endpoint evaluates the proportion of patients achieving at least one developmental milestone across communication, fine motor, and gross motor domains. Milestone gains are assessed using video-evidence review by independent, blinded central raters.
The FDA alignment includes a six-month interim analysis, potentially accelerating the BLA submission, supported by rigorous evaluation criteria and early positive responses observed in Part A of the REVEAL trial.
