Taysha Gene Therapies Announces Progress Across TSHA-102 Pivotal Gene Therapy Program in Rett Syndrome
Rhea-AI Summary
Taysha Gene Therapies (Nasdaq: TSHA) reported progress on its TSHA-102 pivotal program for Rett syndrome, including dosing the first REVEAL pivotal trial patient in Q4 2025 and ongoing enrollment across multiple sites. The REVEAL pivotal trial is a single-arm, open-label study of a single intrathecal dose of 1x1015 vg in 15 females aged 6 to <22 years with a six-month interim analysis that may support a BLA.
The company said it reached written FDA alignment to include at least three months of safety data from the ASPIRE trial (N=3, aged 2 to <4 years) in a planned BLA to enable a broad label for patients ≥2 years. Dosing completion for REVEAL and ASPIRE is expected in Q2 2026, with a REVEAL Part A update expected in H1 2026.
Positive
- First REVEAL pivotal patient dosed in Q4 2025
- FDA provided written alignment to include ≥3 months ASPIRE safety data in planned BLA
- REVEAL six-month interim analysis may serve as BLA submission basis
- Expected completion of REVEAL and ASPIRE dosing in Q2 2026
Negative
- ASPIRE trial enrolls only 3 patients aged 2 to <4 years
- REVEAL is a single-arm, open-label study, which may limit comparative evidence
News Market Reaction – TSHA
On the day this news was published, TSHA gained 7.57%, reflecting a notable positive market reaction. Argus tracked a peak move of +10.5% during that session. Our momentum scanner triggered 13 alerts that day, indicating notable trading interest and price volatility. This price movement added approximately $110M to the company's valuation, bringing the market cap to $1.56B at that time.
Data tracked by StockTitan Argus on the day of publication.
Key Figures
Market Reality Check
Peers on Argus
TSHA fell 6.86% while key gene therapy/biotech peers like QURE, OCS, SANA, EYPT, and UPB showed smaller mixed moves, and momentum peers were split (OCS up, ZBIO down), pointing to a TSHA-specific reaction.
Historical Context
| Date | Event | Sentiment | Move | Catalyst |
|---|---|---|---|---|
| Dec 05 | Inducement grants | Neutral | +7.9% | Stock option inducement grants to new employees under 2023 plan. |
| Nov 04 | Earnings & update | Positive | -4.3% | Q3 2025 results plus TSHA-102 Breakthrough Therapy and pivotal plans. |
| Oct 28 | Earnings preview | Neutral | +2.3% | Announcement of timing and access details for Q3 results call. |
| Oct 16 | Program rights update | Positive | -4.9% | TSHA regained full global rights to lead TSHA-102 Rett program. |
| Oct 09 | Clinical data update | Positive | -1.2% | Supplemental REVEAL Part A data showing 100% response and added skills. |
TSHA often showed negative price reactions following positive TSHA-102 and Rett program updates, indicating a pattern of selling into good news.
Over the last few months, TSHA’s news flow focused on TSHA-102 for Rett syndrome and corporate/financing updates. In October–November 2025, the company regained full TSHA-102 rights, presented Part A REVEAL data with a 100% response rate, and reported Q3 2025 results highlighting FDA Breakthrough Therapy designation and pivotal REVEAL plans. An 8-K detailed expansion of the ATM program. Despite positive clinical and regulatory milestones, several of these updates saw share price declines, so today’s pivotal-program progress update fits a pattern of strong fundamentals with mixed price reactions.
Market Pulse Summary
The stock moved +7.6% in the session following this news. A strong positive reaction aligns with the company’s steady progress on TSHA-102, including pivotal REVEAL enrollment and FDA alignment on ASPIRE data for a planned BLA. Prior TSHA-102 milestones often met with mixed or negative price moves despite favorable updates, so a larger upside move on this detailed pivotal-program roadmap could mark a shift in how investors weigh clinical momentum versus financing and execution risks. High historical volatility suggests that follow-through would still depend on future data readouts.
Key Terms
biologics license application (bla) regulatory
intrathecally (it) medical
aav9 medical
vector genomes (vg) medical
rett syndrome medical
phase 1/2 trials medical
developmental milestones medical
AI-generated analysis. Not financial advice.
First patient dosed in REVEAL pivotal trial evaluating TSHA-102 (N=15, aged 6 to <22 years) in Q4 2025, with enrollment advancing across multiple sites
Reached written alignment with FDA on inclusion of ≥3 months of safety data from ASPIRE trial evaluating TSHA-102 (N=3, aged 2 to <4 years) in planned BLA submission to support a broad label in patients aged ≥2 years with Rett syndrome
Completion of dosing in REVEAL pivotal trial and ASPIRE trial expected in Q2 2026
Longer-term safety and efficacy data update from Part A of REVEAL Phase 1/2 trials expected in H1 2026
DALLAS, Jan. 06, 2026 (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 progress across the TSHA-102 pivotal program, an intrathecally (IT) delivered AAV9 gene therapy with disease modifying potential, in clinical evaluation for the treatment of Rett syndrome.
"Dosing the first patient in our REVEAL pivotal trial last quarter represents a significant milestone in the development of TSHA-102 for Rett syndrome, and enrollment is further advancing across multiple sites. As we progress pivotal development, we continue to maintain consistent and productive dialogue with the FDA,” said Sean P. Nolan, Chairman and Chief Executive Officer of Taysha. “Importantly, we recently reached written alignment with the FDA that our planned BLA submission will include at least three months of safety data from three patients aged two to under four years in the ASPIRE trial to support a broad label for patients aged two years and older with Rett syndrome. We believe this recent alignment on ASPIRE, together with the alignment on a six-month interim analysis for our REVEAL pivotal trial, streamlines our path toward BLA submission for TSHA-102. We expect to complete dosing across our REVEAL and ASPIRE trials in the second quarter of 2026. With an estimated 15,000 to 20,000 patients affected by Rett syndrome across the U.S., EU and U.K. and compelling REVEAL Part A clinical data, we see a significant opportunity to redefine the treatment paradigm for this devastating disease with high unmet need.”
TSHA-102 Program Updates and Overview
- Dosed First Patient in REVEAL Pivotal Trial in the Fourth Quarter of 2025. Additional enrollment continues to advance across multiple clinical trial sites. The single-arm, open-label trial is evaluating a single IT administration of high dose TSHA-102 (1x1015 total vector genomes (vg)) in 15 females between the ages of 6 and <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 of the 28 natural history-defined developmental milestones, with each patient serving as their own control. The study includes a six-month interim analysis that may serve as the basis for Biologics License Application (BLA) submission.
- Reached Written FDA Alignment on ASPIRE Trial and Data for Inclusion in BLA Submission to Enable Broad Label Following Type D Meeting. The Company confirmed prior alignment and obtained further written alignment with the U.S. Food and Drug Administration (FDA) on the ASPIRE safety-focused trial and the data for inclusion in the planned BLA submission to enable broad labeling of TSHA-102 for patients aged ≥2 years with Rett syndrome, including:
- ASPIRE will enroll three females aged 2 to <4 years with Rett syndrome to evaluate the safety and preliminary efficacy of a single IT administration of high dose TSHA-102 (1x1015 total vg), scaled to account for the lower brain volume in 2 to <4‑year‑olds
- A minimum of three months of ASPIRE safety data will be included in the planned BLA submission, while efficacy in the 2 to <6-year-old population will be extrapolated from data collected in the REVEAL pivotal trial, to support a broad label for TSHA-102 in patients aged ≥2 years with Rett syndrome
Anticipated Milestones
- Completion of dosing in the REVEAL pivotal trial is expected in the second quarter of 2026
- Completion of dosing in the ASPIRE trial is expected in the second quarter of 2026
- Update on longer-term safety and efficacy data from Part A of the REVEAL Phase 1/2 trials is expected in the first half of 2026
About TSHA-102
TSHA-102 is a self-complementary intrathecally delivered AAV9 investigational gene transfer therapy in clinical evaluation for Rett syndrome. Designed as a one-time treatment, TSHA-102 aims to address the genetic root cause of the disease by delivering a functional form of MECP2 to cells in the CNS. TSHA-102 utilizes a novel miRNA-Responsive Auto-Regulatory Element (miRARE) technology designed to mediate levels of MECP2 in the CNS on a cell-by-cell basis without risk of overexpression. TSHA-102 has received Breakthrough Therapy, Regenerative Medicine Advanced Therapy, Fast Track and Orphan Drug and Rare Pediatric Disease designations from the FDA, Orphan Drug designation from the European Commission and Innovative Licensing and Access Pathway designation from the Medicines and Healthcare products Regulatory Agency.
About Rett Syndrome
Rett syndrome is a rare neurodevelopmental disorder caused by mutations in the X-linked MECP2 gene encoding methyl CpG-binding protein 2 (MeCP2), which is essential for regulating neuronal and synaptic function in the brain. The disorder is characterized by loss of communication and hand function, slowing and/or regression of development, motor and respiratory impairment, seizures, intellectual disabilities and shortened life expectancy. Rett syndrome progression is divided into four key stages, beginning with early onset stagnation at 6 to 18 months of age followed by rapid regression, plateau and late motor deterioration. Rett syndrome primarily occurs in females and is one of the most common genetic causes of severe intellectual disability. Currently, there are no approved disease-modifying therapies that treat the genetic root cause of the disease. Rett syndrome caused by a pathogenic/likely pathogenic MECP2 mutation is estimated to affect between 15,000 and 20,000 patients in the U.S., EU, and U.K.
About Taysha Gene Therapies
Taysha Gene Therapies (Nasdaq: TSHA) 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. Its lead clinical program TSHA-102 is in development for Rett syndrome, a rare neurodevelopmental disorder with no approved disease-modifying therapies that address the genetic root cause of the disease. With a singular focus on developing transformative medicines, Taysha aims to address severe unmet medical needs and dramatically improve the lives of patients and their caregivers. The Company’s management team has proven experience in gene therapy development and commercialization. Taysha leverages this experience, its manufacturing process and a clinically and commercially proven AAV9 capsid in an effort to rapidly translate treatments from bench to bedside. For more information, please visit www.tayshagtx.com.
Forward-Looking Statements
This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as “anticipates,” “believes,” “expects,” “intends,” “projects,” “plans,” and “future” or similar expressions are intended to identify forward-looking statements. Forward-looking statements include, but are not limited to, statements concerning the potential of TSHA-102 and Taysha’s other product candidates to positively impact quality of life and alter the course of disease in the patients Taysha seeks to treat, its research, development and regulatory plans for its product candidates, communications with the FDA, including with respect to the BLA for TSHA-102, the potential for these product candidates to receive regulatory approval from the FDA or equivalent foreign regulatory agencies, and whether, if approved, these product candidates will be successfully distributed and marketed and the potential market opportunity for Taysha’s product candidates. Forward-looking statements are based on management’s current expectations and are subject to various risks and uncertainties that could cause actual results to differ materially and adversely from those expressed or implied by such forward-looking statements. Accordingly, these forward-looking statements do not constitute guarantees of future performance, and you are cautioned not to place undue reliance on these forward-looking statements. Risks regarding Taysha’s business are described in detail in Taysha’s Securities and Exchange Commission (“SEC”) filings, including in Taysha’s Annual Report on Form 10-K for the full-year ended December 31, 2024 and Quarterly Report on Form 10-Q for the quarter ended September 30, 2025, which are available on the SEC’s website at www.sec.gov. Additional information will be made available in other filings that Taysha makes from time to time with the SEC. These forward-looking statements speak only as of the date hereof, and Taysha disclaims any obligation to update these statements except as may be required by law.
Company Contact:
Hayleigh Collins
Senior Director, Corporate Communications and Investor Relations
Taysha Gene Therapies, Inc.
hcollins@tayshagtx.com
Media Contact:
Carolyn Hawley
Inizio Evoke
Carolyn.hawley@inizioevoke.com
FAQ
What progress did TSHA (Nasdaq: TSHA) report for TSHA-102 in January 2026?
How many patients and what dose are being used in the REVEAL pivotal trial (TSHA-102)?
What data from the ASPIRE trial will TSHA include in the planned BLA for TSHA-102?
When does Taysha expect to complete dosing across REVEAL and ASPIRE trials for TSHA-102?
When will Taysha provide longer-term safety and efficacy data updates for TSHA-102?
