Taysha Gene Therapies, Inc. announced multiple presentations highlighting its TSHA-102 program for Rett syndrome at the 2026 International Rett Syndrome Foundation (IRSF) Rett Syndrome Scientific Meeting held in Prior Lake, MN, from June 29 to July 1, 2026. The company disclosed that recently revealed longer-term data from the REVEAL Part A trial demonstrated a broad, multi-domain functional impact that deepened over time through at least 12 months post-treatment, regardless of age or disease severity. Additionally, a natural history data analysis indicated a clear developmental plateau after 6 years of age, supporting a stable population for the ongoing REVEAL pivotal trial.

Clinical and Preclinical Findings

The presentations included safety and efficacy results from the REVEAL Part A Phase 1/2 trial in pediatric and adolescent/adult cohorts, delivered by Principal Investigator Elsa Rossignol, M.D. New data supported the Rett Syndrome Developmental Milestone Assessment (RS-DMA) as a psychometrically valid, FDA-supported primary endpoint for single-arm interventional studies. Preclinical findings demonstrated superior MeCP2 expression of self-complementary AAV9 compared to single-stranded vectors, supporting effective central nervous system delivery via intrathecal administration.

About TSHA-102

TSHA-102 is a self-complementary intrathecally delivered AAV9 investigational gene transfer therapy designed as a one-time treatment to address the genetic root cause of Rett syndrome. It delivers a functional form of MECP2 to cells in the central nervous system utilizing miRNA-Responsive Auto-Regulatory Element (miRARE) technology to mediate expression levels without risk of overexpression. TSHA-102 has received Breakthrough Therapy, Regenerative Medicine Advanced Therapy, Fast Track, Orphan Drug, and Rare Pediatric Disease designations from the FDA, as well as Orphan Drug designation from the European Commission and Innovative Licensing and Access Pathway designation from the Medicines and Healthcare products Regulatory Agency.

Taysha Gene Therapies, Inc. has priced an underwritten public offering of 32,500,001 shares of its common stock at a price to the public of $6.00 per share. The company also offered pre-funded warrants to purchase 833,333 shares of its common stock at an offering price of $5.999 per pre-funded warrant. The gross proceeds from the offering are expected to be approximately $200.0 million, before deducting underwriting discounts and commissions and other offering expenses. The offering is expected to close on or about June 26, 2026, subject to customary closing conditions.

All securities are being offered by Taysha, which has granted the underwriters a 30-day option to purchase up to an additional 5,000,000 shares of common stock at the public offering price, less underwriting discounts and commissions. A shelf registration statement was filed with the Securities and Exchange Commission (SEC) on November 4, 2025, and became automatically effective upon filing. The offering is being made only by means of a written prospectus and prospectus supplement.

Jefferies, Goldman Sachs & Co. LLC, Piper Sandler, and Cantor are acting as joint book-running managers for the proposed offering. Baird is serving as the lead manager. Taysha 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.

Taysha’s lead clinical program, TSHA-102, is in development for Rett syndrome, a rare neurodevelopmental disorder with no approved disease-modifying therapies. The company leverages its manufacturing process and a clinically and commercially proven AAV9 capsid to translate treatments from bench to bedside.