Healthcare Professionals

We are committed to providing healthcare professionals with the information and programs that will support their efforts to treat rare, monogenic diseases of the central nervous system.

Clinical Trials

REVEAL Pivotal Trial of TSHA-102 (Part B)

The REVEAL Pivotal Trial is a single-arm, open-label study evaluating the efficacy and safety of TSHA-102 in females with Rett syndrome, with each patient serving as their own control. Each participant will receive a single administration of the high dose (1×10¹⁵ total vector genomes (vg)) of TSHA-102 delivered by lumbar intrathecal injection.

The study will enroll 15 females aged 6 to <22 years in the developmental plateau population of Rett syndrome. This population of patients has a low likelihood (0% to <6.7%) of gaining new or regaining developmental milestones that were lost after a defined number of years, based on Taysha’s natural history data analysis (N = ~1100 females with Rett syndrome, with up to 14 years follow-up)18. The primary endpoint will assess response rate, defined as the percentage of patients who gain or regain ≥ one developmental milestone from a list of 28 defined milestones across the core functional domains of communication, fine motor and gross motor, following TSHA-102 administration.

Patient enrollment is expected to begin in the fourth quarter of 2025.

Pediatric Safety-Focused Study of TSHA-102 

Taysha is also planning a safety-focused study evaluating the safety and preliminary efficacy of TSHA-102 in females aged 2 to <6 years in the pre-developmental plateau population of Rett syndrome. Efficacy data will be extrapolated from the REVEAL Pivotal Trial. This approach is intended to enable access across a broad population of patients with Rett syndrome.

REVEAL Phase 1/2 Adolescent and Adult Trial (Part A)

The REVEAL Phase 1/2 Adolescent and Adult Trial is a first-in-human, open-label, randomized, dose-escalation and dose-expansion study evaluating the safety and preliminary efficacy of TSHA-102 in females aged 12 and older with Rett syndrome.

A total of six participants aged 15 to 21 years were treated with TSHA-102 in this study. Two of the participants received the lower dose (5.7×10¹⁴ vg) of TSHA-102 and four of the participants received the higher dose (1×10¹⁵ vg) of TSHA-102. These participants will continue to be monitored throughout the study. Enrollment for this trial is complete.

REVEAL Phase 1/2 Pediatric Trial (Part A)

The REVEAL Phase 1/2 Pediatric Trial is a first-in-human, open-label, randomized, dose-escalation and dose-expansion study evaluating the safety and preliminary efficacy of TSHA-102 in females aged 5 to 8 years with Rett syndrome.

A total of six participants aged 6 to 8 years were treated with TSHA-102 in this study. Two of the participants received the lower dose (5.7×10¹⁴ vg) of TSHA-102 and four of the participants received the higher dose (1×10¹⁵ vg) of TSHA-102. These participants will continue to be monitored throughout the study. Enrollment for this trial is complete.

If you are a healthcare provider and have questions or would like additional information on the trials, please contact medinfo@tayshagtx.com.

For additional information for patients and caregivers, please visit our Patient & Caregivers page.

Scientific Posters & Publications

  • 2025 International Rett Syndrome Foundation (IRSF) Rett Syndrome Scientific Meeting

    18. REVEAL Adolescent/Adult and Pediatric Clinical Trial Update: Safety and Efficacy Data on TSHA-102 AAV9 Investigational Gene Therapy in Clinical Evaluation for Rett Syndrome

    17. Every Gain, Expanding Possibilities: Caregiver Insights on Meaningful Improvement in Rett Syndrome Gene Therapy (GT)

    16. rAAV9 Vector Biodistribution in Brain and Spinal Cord via Lumbar Intrathecal Infusion in Nonhuman Primates (NHP): Assessing the Administration Route Leveraged in TSHA-102 Rett Syndrome Clinical Trials

  • European Society of Gene & Cell Therapy 2024 Annual Congress

    15. Broad CNS Biodistribution of AAV9-based Gene Therapies Delivered by Intrathecal Lumbar Puncture in Non-Human Primates

  • 9th World Rett Syndrome Congress

    14. First-cohort Data from the REVEAL Adolescent/Adult and Pediatric Studies of TSHA-102 Gene Therapy for Rett Syndrome

  • 2024 International Rett Syndrome Foundation (IRSF) Rett Syndrome Scientific Meeting

    13. TSHA-102 gene therapy for Rett syndrome: First-cohort data from the REVEAL Adolescent/ Adult and Pediatric studies

  • British Paediatric Neurology Association 2024 Conference

    12. Early safety and efficacy observations following the first use of TSHA-102 gene therapy in patients with Rett Syndrome

  • European Society of Gene & Cell Therapy 30th Annual Congress 2023

    11. The microRNA-responsive autoregulatory element from TSHA-102 for Rett Syndrome modulates therapeutic transgene expression in response to cellular MeCP2 in mouse and human cell lines

    10. Early safety and efficacy observations following the first use of TSHA-102 gene therapy in a patient with Rett Syndrome

  • Rett Syndrome Research Trust 2023 Genetic Medicines Summit

    9. Early safety and efficacy observations following the first use of TSHA-102 gene therapy in a patient with Rett Syndrome

    8. Design of the REVEAL Pediatric study of TSHA-102 gene therapy for Rett Syndrome

  • American Society of Gene and Cell Therapy 26th Annual Meeting 2023

    7. A Human-ready Regulated AAV9/miniMECP2- miRARE Gene Therapy (TSHA-102) Improves Survival, Weight, and Behavior After Intracerebroventricular (ICV) Dosing in the Neonatal Knockout Rett (RTT) Mouse Model

  • European Society of Gene & Cell Therapy 29th Annual Congress 2022

    6. Assessment of Safety and Biodistribution of a miniMECP2 AAV9 Vector for Gene-replacement Therapy of Rett Syndrome in Non-human Primates (NHPs)

    5. Assessment of Safety of miniMECP2 AAV9 vector (TSHA-102) for Gene-replacement Therapy of Rett Syndrome in Rats

  • American Society of Gene and Cell Therapy 25th Annual Meeting 2022

    4. Safety and Biodistribution Assessment in Non-Human Primates (NHP) of a miniMECP2 AAV9 Vector for Gene-Replacement Therapy of Rett Syndrome

    3. Safety Assessment of High-Dose miniMECP2 AAV9 Gene-Replacement Therapy (TSHA-102) for Rett Syndrome in Rats

  • International Rett Syndrome Foundation Meeting 2022

    2. Safety and Biodistribution Assessment in Non-human Primates (NHPs) of a miniMECP2 AAV9 Vector for Gene-replacement Therapy of Rett Syndrome

  • ASGCT 23rd Annual Meeting 2020

    1. A New Approach for Designing a Feedback-Enabled AAV Genome Improves Therapeutic Outcomes of MiniMeCP2 Gene Transfer in Mice Modeling Rett Syndrome (RTT)

Expanded Access Policy

At Taysha, we are focused on running well-designed clinical trials to assess the safety and efficacy of investigational therapies and provide the highest probability of bringing an approved therapy to the broader patient community. We are collaborating closely with patients, caregivers, patient organizations and medical experts to conduct clinical trials.

Expanded Access, sometimes called Managed Access, Compassionate Use, Named Patient or Early Access, is a potential pathway for a patient with an immediately life-threatening condition, serious disease or condition to gain access to an investigational medical product (drug, biologic, or medical device) for treatment outside of clinical trials when no comparable or satisfactory alternative therapy options are available.

Taysha evaluates physician requests for Expanded Access outside of a clinical study on a case-by-case basis when certain conditions are met. All Expanded Access requests must be submitted by the patient’s treating physician.

Patients or caregivers who are interested in learning more should speak with their physician. Physicians may submit questions about clinical trials and Taysha’s Expanded Access Policy to .

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