Commenced site activation for REVEAL pivotal trial in accordance with previously aligned upon key design elements, following receipt of No Objection Letter (NOL) from
High dose and low dose TSHA-102 continue to be generally well tolerated with no treatment-related SAEs or DLTs in the 12 patients treated in Part A of REVEAL Phase 1/2 trials as of
Part A data from REVEAL Phase 1/2 trials presented at IRSF Scientific Meeting showed 100% response rate for pivotal trial primary endpoint of gain/regain of ≥ one developmental milestone, corroborated by improvements in key secondary endpoints post-TSHA-102
Company anticipates reporting new supplemental REVEAL Part A clinical data supporting TSHA-102 therapeutic impact in Q4 2025
Gross proceeds of
Conference call and webcast today at 8:30 AM Eastern Time
“We have made strong progress across the Company supporting the advancement of our TSHA-102 development program toward potential registration for females two years and older with Rett syndrome. In May, we announced alignment with the FDA on key design elements of our REVEAL pivotal trial, and subsequently, submitted our IND application and CTA amendments to both the FDA and
Recent Corporate and TSHA-102 Program Highlights
- Commenced Site Activation for REVEAL Pivotal Trial Following Regulatory Feedback. In
May 2025 , Taysha announced alignment with theU.S. Food and Drug Administration (FDA) on key elements of the REVEAL pivotal Part B trial design and next steps for enabling study initiation. Subsequently, the Company submitted its Investigational New Drug (IND) application amendment to the FDA and Clinical Trial Application Amendment (CTA-A) toHealth Canada . Taysha commenced site activation for the REVEAL pivotal trial in accordance with previously aligned upon key design elements, following receipt of a NOL fromHealth Canada and written feedback from the FDA- Trial Design: Single-arm, open-label trial, with each patient serving as their own control
- Dose and Administration: Single administration of high dose of TSHA-102 (1x1015 total vector genomes (vg)) delivered by lumbar intrathecal (IT) injection
- Patient Population: Enrolling 15 females aged 6 to <22 years in the developmental plateau population of Rett syndrome; these patients have 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)
- 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
- Selected milestones reflect meaningful functional gains and improvements in activities of daily living identified through caregiver research, and have a documented likelihood of spontaneous gain/regain of <6.7% in the untreated Rett syndrome population aged ≥ 6 years
- Standardized milestone assessments will be administered and captured on video at pre- and post-treatment timepoints; video-evidenced determination of milestone gain/regain will be determined by independent, blinded central raters based on prespecified definitions of achievement for each milestone
- The Company plans to perform a 12-month primary analysis and a 6-month interim analysis
- Previously disclosed clinical data from Part A of REVEAL Phase 1/2 Adolescent/Adult and Pediatric trials (N=10, 6-21 years) demonstrating a 100% response rate indicate the pivotal trial is well powered to establish efficacy of TSHA-102 (
May 2025 data cutoff)
- Previously disclosed clinical data from Part A of REVEAL Phase 1/2 Adolescent/Adult and Pediatric trials (N=10, 6-21 years) demonstrating a 100% response rate indicate the pivotal trial is well powered to establish efficacy of TSHA-102 (
- Key Secondary Endpoints: Include the average number of total developmental milestones gained/regained per patient following TSHA-102, as well as clinician-assessed outcome measures: Revised Motor Behavior Assessment (R-MBA) and Clinician Global Impression – Improvement (CGI-I)
- Obtained Written Alignment from FDA on Extrapolation Approach in a Safety-Focused Study in Females 2 to <6 Years of Age. Planned safety-focused study will evaluate the safety and preliminary efficacy of TSHA-102 in the pre-developmental plateau population (aged 2 to <6 years) of females with Rett syndrome. Efficacy will be extrapolated from the REVEAL pivotal trial. This approach is intended to enable access across a broad population of patients with Rett syndrome
- High and Low Dose of TSHA-102 Continue to be Generally Well Tolerated. High dose (1x1015 total vg) and low dose (5.7x1014 total vg) of TSHA-102 continue to be generally well tolerated with no treatment-related serious adverse events (SAEs) or dose-limiting toxicities (DLTs) in the 12 pediatric, adolescent and adult patients dosed across Part A of the REVEAL Phase 1/2 trials as of the
August 2025 data cutoff. This includes eight patients in the high dose cohort and four patients in the low dose cohort. - Presented Data Supporting TSHA-102 Clinical Program at IRSF. Three oral presentations were delivered at the 2025 International Rett Syndrome Foundation (IRSF) Rett Syndrome Scientific Meeting. The presentations, which are available on the Company’s website, highlighted the following:
- Clinical data from Part A of REVEAL Phase 1/2 trials (
May 2025 data cutoff) - Caregiver research on meaningful improvements in gene therapy for Rett syndrome supporting the primary endpoint for the REVEAL pivotal trial
- Preclinical data demonstrating broad biodistribution of AAV9 gene therapy vectors across the brain and spinal cord regions following lumbar IT administration in non-human primates
- Clinical data from Part A of REVEAL Phase 1/2 trials (
- Completed Public Follow-on Offering with Total Gross Proceeds of
$230 Million . Proceeds included full exercise of the underwriters’ option to purchase additional shares; anticipated cash runway extends into 2028
Anticipated Milestones
- REVEAL pivotal trial patient enrollment expected to begin in the fourth quarter of 2025
- New supplemental clinical data from Part A of REVEAL Phase 1/2 trials supporting the broad therapeutic impact of TSHA-102 anticipated in the fourth quarter of 2025
Second Quarter 2025 Financial Highlights
Research and Development Expenses: Research and development expenses were
General and Administrative Expenses: General and administrative expenses were
Net Loss: Net loss for the three months ended
Cash and Cash Equivalents: As of
Conference Call and Webcast Information
Taysha management will hold a conference call and webcast today at 8:30 a.m. ET to review its financial and operating results and provide a corporate update. The dial-in number for the conference call is 877-407-0792 (
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 Regenerative Medicine Advanced Therapy, Fast Track and Orphan Drug and Rare Pediatric Disease designations from the FDA, Orphan Drug designation from the
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
About
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, including the reproducibility and durability of any favorable results initially seen in patients dosed to date in clinical trials, including with respect to functional milestones, to positively impact quality of life and alter the course of disease in the patients Taysha seeks to treat, Taysha’s research, development and regulatory plans for TSHA-102, including the timing of initiating additional trials, reporting data from Taysha’s clinical trials and making regulatory submissions, communications with and feedback from the FDA and
Condensed Consolidated Statements of Operations (in thousands, except share and per share data) |
||||||||||||||||
| For the Three Months Ended |
For the Six Months Ended |
|||||||||||||||
| 2025 | 2024 | 2025 | 2024 | |||||||||||||
| Revenue | $ | 1,986 | $ | 1,112 | $ | 4,288 | $ | 4,523 | ||||||||
| Operating expenses: | ||||||||||||||||
| Research and development | 20,141 | 15,073 | 35,706 | 35,730 | ||||||||||||
| General and administrative | 8,598 | 7,338 | 16,756 | 14,422 | ||||||||||||
| Total operating expenses | 28,739 | 22,411 | 52,462 | 50,152 | ||||||||||||
| Loss from operations | (26,753 | ) | (21,299 | ) | (48,174 | ) | (45,629 | ) | ||||||||
| Other income (expense): | ||||||||||||||||
| Change in fair value of warrant liability | (273 | ) | 195 | (171 | ) | (142 | ) | |||||||||
| Change in fair value of term loan | (1,461 | ) | (1,279 | ) | (2,991 | ) | (2,332 | ) | ||||||||
| Interest income | 1,859 | 1,440 | 3,185 | 3,133 | ||||||||||||
| Interest expense | (17 | ) | (27 | ) | (36 | ) | (56 | ) | ||||||||
| Other (expense), income | (237 | ) | 42 | (224 | ) | 37 | ||||||||||
| Total other (expense) income, net | (129 | ) | 371 | (237 | ) | 640 | ||||||||||
| Net loss | $ | (26,882 | ) | $ | (20,928 | ) | $ | (48,411 | ) | $ | (44,989 | ) | ||||
| Net loss per common share, basic and diluted | $ | (0.09 | ) | $ | (0.09 | ) | $ | (0.17 | ) | $ | (0.19 | ) | ||||
| Weighted average common shares outstanding, basic and diluted | 297,988,978 | 232,821,553 | 283,726,888 | 232,035,448 | ||||||||||||
Condensed Consolidated Balance Sheet Data (in thousands, except share and per share data) |
||||||||
2025 |
2024 |
|||||||
| ASSETS | ||||||||
| Current assets: | ||||||||
| Cash and cash equivalents | $ | 312,761 | $ | 139,036 | ||||
| Restricted cash | 449 | 449 | ||||||
| Prepaid expenses and other current assets | 3,054 | 2,645 | ||||||
| Total current assets | 316,264 | 142,130 | ||||||
| Restricted cash | 2,151 | 2,151 | ||||||
| Property, plant and equipment, net | 6,957 | 7,485 | ||||||
| Operating lease right-of-use assets | 7,773 | 8,381 | ||||||
| Other non-current assets | 186 | 217 | ||||||
| Total assets | $ | 333,331 | $ | 160,364 | ||||
| LIABILITIES AND STOCKHOLDERS' EQUITY | ||||||||
| Current liabilities: | ||||||||
| Accounts payable | $ | 7,713 | $ | 3,592 | ||||
| Accrued expenses and other current liabilities | 12,151 | 12,862 | ||||||
| Deferred revenue | 5,485 | 9,773 | ||||||
| Total current liabilities | 25,349 | 26,227 | ||||||
| Term loan, net | 41,051 | 43,942 | ||||||
| Operating lease liability, net of current portion | 16,808 | 17,361 | ||||||
| Other non-current liabilities | 1,396 | 1,309 | ||||||
| Total liabilities | 84,604 | 88,839 | ||||||
| Stockholders' equity | ||||||||
| Preferred stock, |
— | — | ||||||
| Common stock, |
3 | 2 | ||||||
| Additional paid-in capital | 900,139 | 677,859 | ||||||
| Accumulated other comprehensive loss | (699 | ) | (4,031 | ) | ||||
| Accumulated deficit | (650,716 | ) | (602,305 | ) | ||||
| Total stockholders’ equity | 248,727 | 71,525 | ||||||
| Total liabilities and stockholders' equity | $ | 333,331 | $ | 160,364 | ||||
Company Contact:
Senior Director, Corporate Communications and Investor Relations
hcollins@tayshagtx.com
Media Contact:
Inizio Evoke
Carolyn.hawley@inizioevoke.com
Source: Taysha Gene Therapies, Inc.