Taysha Gene Theries重新获得其主导TSHA-102 Rett综合征临床评估项目的全部权利; TSHA-102已证明令人信服的A部分REVEAL 1/2期安全性和有效性数据，获得FDA突破性治疗指定，并正在以明确的途径推进潜在注册

DALLAS, Oct. 16, 2025 (GLOBE NEWSWIRE) -- 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 the Company has regained full rights to its lead TSHA-102 program in clinical evaluation for Rett syndrome. The 2022 Option Agreement between Astellas and Taysha, which had granted Astellas the exclusive option to enter a negotiation period to obtain an exclusive license to TSHA-102 in Rett syndrome and certain rights with respect to change in control transactions involving Taysha, has expired.

In accordance with the 2022 Option Agreement, Taysha delivered a TSHA-102 data package to Astellas in mid-2025 that contained the previously disclosed Part A REVEAL clinical data (May 2025 data cutoff), initiating a 90-day review period for Astellas to elect to exercise an option to trigger exclusive negotiations for a transaction. These data were shared with the U.S. Food and Drug Administration (FDA) as part of the application for, and subsequent receipt of, Breakthrough Therapy designation for TSHA-102. Following the expiration of the Option Agreement, Taysha now holds unencumbered rights to the TSHA-102 program.

These previously disclosed Part A REVEAL clinical data (May 2025 data cutoff) demonstrated a generally well-tolerated safety profile and a 100% response rate post-TSHA-102 for the pivotal trial primary endpoint of the gain/regain of ≥ one defined developmental milestone, with <6.7% likelihood of being achieved without treatment based on natural history data. These findings were corroborated by dose-dependent improvements in multiple outcome measures, including Revised Motor Behavior Assessment (R-MBA) and Clinician Global Impression – Improvement (CGI-I).

"We greatly appreciate the collaborative relationship we've had with Astellas, and the progress made to date across our TSHA-102 program, including recent clinical data further highlighting the therapy's broad and consistent impact and the receipt of Breakthrough Therapy designation from the FDA," said Sean P. Nolan, Chairman and Chief Executive Officer of Taysha. "We are thrilled to regain full global rights to our lead TSHA-102 Rett syndrome program, which enables full strategic flexibility and optionality as we continue to advance the program and focus on driving long-term value."

Mr. Nolan continued, "With an estimated 15,000 to 20,000 patients across the U.S., EU and U.K. suffering from Rett syndrome, we believe the profound unmet medical need paired with the robust clinical data observed in Part A of our REVEAL trials highlight the significant market opportunity for TSHA-102. We believe our strong balance sheet, team with proven gene therapy expertise and clear path to registration position us well to advance TSHA-102 toward late-stage development and potential commercialization, if approved. We remain focused on execution, with dosing of the first patient in the REVEAL pivotal trial scheduled this quarter."

Taysha has finalized FDA alignment on the REVEAL pivotal trial protocol and statistical analysis plan, which includes a 6-month interim analysis that may serve as the basis for BLA submission. The REVEAL pivotal trial is a single-arm, open-label trial with each patient serving as their own control. A single intrathecal administration of high dose TSHA-102 (1x1015 total vector genomes) will be evaluated in 15 females between the ages of 6 and less than 22 years in the developmental plateau population of Rett syndrome. The primary endpoint will assess response rate, defined as the percentage of patients who gain or regain one or more defined developmental milestone from a list of 28 across the core functional domains of communication, fine motor and gross motor, following dosing with TSHA-102. Selected milestones have a 0% to <6.7% likelihood of spontaneous gain/regain in the untreated Rett syndrome population aged ≥ 6 years based on natural history data. Standardized milestone assessments will be administered and captured on video at pre- and post-treatment timepoints, with determination of milestone gain/regain by video-evidence review by independent, blinded central raters based on prespecified definitions of achievement for each milestone. Dosing of the first patient in the REVEAL pivotal trial has been scheduled for the current quarter.