TSHA-102 - (REVEAL)

June 22, 2026: Taysha Gene Therapies, Inc. (NASDAQ: TSHA) announced completion of dosing in its overenrolled REVEAL pivotal trial of TSHA-102 (intrathecal AAV9 gene transfer) for Rett syndrome and reported positive longer-term follow-up from REVEAL Phase 1/2 Part A.

REVEAL pivotal trial: 17 females (ages 6 to <22; developmental plateau population) have been dosed with a single high dose (1x10^15 vg). Primary endpoint is response rate (gain/regain ≥1 of 28 natural history-defined developmental milestones); 33% response is stated as the minimum threshold to reject a 6.7% null hypothesis. Interim analysis to support a planned BLA is expected after all patients reach 6 months follow-up; FDA discussion planned for early 2027, with topline interim data and FDA feedback on the BLA pathway expected in 1H 2027. As of a June 2026 cutoff across REVEAL Phase 1/2 and pivotal trials (N=29), TSHA-102 was generally well tolerated with no treatment-related SAEs or DLTs.

ASPIRE trial: enrollment exceeded the initial N=3; company plans to dose 4 females ages 2 to <4, with completion expected July 2026. At least 3 months of ASPIRE safety data is planned for inclusion in the BLA.

REVEAL Phase 1/2 Part A (May 2026 cutoff; N=12, ages 6–21; ≥12 months follow-up): 100% gained/regained ≥1 developmental milestone; 310 total functional gains (31 milestones; 279 other gains) were reported at ≥12 months (~26 per patient), with gains increasing from 6 to 12+ months; longest follow-up reported was 30 months. PPQ campaign completion is expected in Q4 2026.