Taysha Gene Therapies (TSHA) investor relations material

Executive summary

• Achieved FDA Breakthrough Therapy designation for TSHA-102 in Rett syndrome, reflecting strong clinical evidence and significant unmet need, and received additional regulatory designations including RMAT, Orphan Drug, Fast Track, and ILAP.

• Finalized alignment with FDA on pivotal REVEAL trial protocol and statistical analysis plan, including a 6-month interim analysis to potentially expedite BLA submission.

• Regained full, unencumbered global rights to TSHA-102 after expiration of the Astellas option agreement, providing full strategic flexibility.

• Strengthened commercial leadership with the appointment of a new Chief Commercial Officer to support late-stage development and commercialization.

• All 12 patients in Part A of REVEAL trials showed no treatment-related serious adverse events or dose-limiting toxicities; high dose cohort demonstrated faster and deeper functional gains.

Financial highlights

• Research and development expenses were $25.7 million for Q3 2025, up from $14.9 million in Q3 2024, and $61.5 million for the nine months ended September 30, 2025, up from $50.7 million year-over-year, driven by clinical trial, manufacturing activities, and increased headcount.

• General and administrative expenses were $8.3 million for Q3 2025, up from $7.9 million, mainly due to debt issuance costs.

• Net loss for Q3 2025 was $32.7 million ($0.09 per share), compared to $25.5 million ($0.10 per share) in Q3 2024; net loss for the nine months ended September 30, 2025 was $81.1 million, up from $70.5 million year-over-year.

• Cash and cash equivalents totaled $297.3 million as of September 30, 2025, following a $215.6 million equity raise in May 2025 and a $50 million term loan draw in August 2025, expected to fund operations into 2028.

• Total assets increased to $316.6 million as of September 30, 2025, from $160.4 million at year-end 2024; stockholders' equity increased to $219.0 million.

Outlook and guidance

• Dosing of the first patient in the pivotal REVEAL trial is scheduled for Q4 2025, with rapid enrollment expected across multiple sites.

• Six-month interim analysis may serve as the basis for BLA submission, potentially accelerating submission by at least two quarters.

• Longer-term Part A clinical data expected in the first half of 2026.

• Anticipates including data from younger patients (ages 2-5) in the BLA submission, aiming for a broad label.

• Cash runway expected to fund operations into 2028, with additional capital needed for future development, manufacturing, and commercialization activities.