Taysha Gene Therapies, Inc. · NASDAQ:TSHA
Taysha Gene Therapies — Corporate Update (June 2026)
28 slides from Taysha Gene Therapies's corporate update, June 2026
Slide 1: TSHA-102 Rett Syndrome program Update: Longer-term Results from REVEAL Phase 1/2 trials
TSHA-102 Rett Syndrome program Update: Longer-term Results from REVEAL Phase 1/2 trials June 2026 1
Slide 2: Legal disclosure
Legal disclosure FORWARD LOOKING STATEMENTS This presentation contains forward-looking statements that involve substantial risks and uncertainties. All statements, other than statements of historical facts, contained in this presentation, including statements regarding the potential of TSHA-102, the
Slide 3: Agenda
Agenda Rett Syndrome Overview & REVEAL Pivotal Trial Update TSHA-102 Clinical Data from Part A of REVEAL Phase 1/2 Trials Next Steps & Concluding Remarks 3
Slide 4: No approved disease-modifying treatments address the genetic root cause of Rett syndrome
There are no approved disease-modifying treatments that address the genetic root cause of Rett syndrome High Unmet Medical Need Significant Market Opportunity Current standard of care focused on o Estimated 15,000 to 20,000 patients in major symptom management1 global markets (U.S., EU+U.K.)3 Patien
Slide 5: Natural history study informed REVEAL pivotal trial inclusion criteria and endpoint design
Rigorous analysis of the Rett Syndrome Natural History Study informed the inclusion criteria and endpoint design for the REVEAL pivotal trial1 Graph is for illustrative purposes only and is not derived from natural history data. Probability of Gaining/Regaining Developmental Milestones Results supp
Slide 6: Completed dosing in REVEAL pivotal trial to support BLA submission
Completed dosing in REVEAL pivotal trial for TSHA-102 to support BLA submission – on track to complete six-month interim analysis Single-arm, open-label trial, using each patient as ⚬ SAP: 33% response rate is the minimum threshold for success sufficient to reject the null hypothesis of 6.7%2 own co
Slide 7: Longer-term REVEAL Part A data showed broad, consistent functional gains deepening over time
Longer-term REVEAL Part A data demonstrated broad, consistent functional gains that deepened over time regardless of patient age, disease severity or genotype1 ⚬ 100% of patients (N=12, 6-21 years) in the developmental plateau population of Rett gained/regained ≥1 developmental milestone ⚬ Longer-te
Slide 8: Rigorous evaluation criteria applied to Part A data
Rigorous evaluation criteria applied to Part A data enabled reliable, objective assessment of TSHA-102 efficacy Evaluation of Functional Gains Primary evidence of efficacy Additional evidence of functional gain Developmental Milestones (DM) Additional Skills and Improvements The functional gain of ≥
Slide 9: All 12 patients gained/regained at least one developmental milestone
All 12 pediatric, adolescent and adult patients across a broad range of disease severity gained/regained ≥one developmental milestone post-TSHA-102 with a <6.7% likelihood of being achieved without treatment based on NHS data1 Cohort 1: Low Dose Cohort Cohort 1: 14 Low Dose Cohort 2: 2: High High Do
Slide 10: Rapid and robust response rate in REVEAL Part A
Rapid and robust response rate in REVEAL Part A supports the pivotal trial is well-powered to establish efficacy 100% Response Rate 83% (12/12) 75% Response Rate Response Rate (10/12) (9/12) REVEAL Part A data exceeded 33% FDA-aligned response rate threshold FDA-aligned Minimum for pivotal trial suc
Slide 11: 31 total developmental milestones achieved across core disease domains
31 total developmental milestones achieved across core disease domains post-TSHA-102 reflect meaningful improvements in daily living Communication Fine Motor Gross Motor Spoke in phrases with meaning Used utensils to eat without assistance Walked with support Used word(s) with meaning Used utensils
Slide 12: Consistent treatment benefit across pediatric and adolescent/adult patients
TSHA-102 delivered consistent and clinically meaningful treatment benefit across pediatric and adolescent/adult patients with Rett syndrome Results support the broad treatment potential of TSHA-102 16 15 Total Developmental Total Developmental Milestones Achieved Across Milestones Achieved Across 6
Slide 13: Early and sustained developmental milestone gains across three core domains
TSHA-102 drove early and sustained developmental milestone gains with additional gains over time across the three core disease domains Assessed by multiple independent central raters using video-evidenced review in accordance with the pivotal trial criteria # of Developmental Milestones Achieved Tot
Slide 14: Durable skill gains and improvements accumulated over time
Patients achieved durable, clinically meaningful skill gains and improvements that accumulated over time in addition to developmental milestones Total Functional Gains Achieved Post-TSHA-102 Skills/Improvements Achieved Post-TSHA-102 # of Developmental Milestones and Additional 2Skills and Improveme
Slide 15: 310 total functional gains achieved post-TSHA-102
310 total functional gains achieved post-TSHA-102 highlight its broad functional impact 31 developmental milestones, 279 skill gains and including:1 Walked with support 310 improvements, including:2 Improved motor skills and hand use Climbed down stairs with support Functional Gains Understood and r
Slide 16: REVEAL caregiver testimonials highlight quality of life impact
REVEAL caregiver testimonials post-TSHA-102 highlight the impact of functional gains on quality of life “ She has lots of interest in the world around her. She says what she wants, and we know what she doesn’t! We can negotiate with her – if I ask her if she wants this or that, she’ll respond, ‘no w
Slide 17: Meet Jane, a 21-year-old woman living with Rett syndrome
Meet Jane, a 21-year-old woman living with Rett syndrome Unable to express her Walked independently Non-verbal wants and needs with slow, unsteady Daily to weekly and rarely made No purposeful hand seizures use and very rarely movements, requiring Low interest in choices close supervision social int
Slide 18: Jane achieved sustained, meaningful functional gains
Jane, 21-years-old at dosing, achieved sustained, meaningful functional gains Points to what she Speaks in phrases wants and Improved gait and with meaning consistently makes Consistently uses her mobility with reduced Monthly seizures choices fingers to self-feed bradykinesia Consistently engaged a
Slide 19: Meet Sarah, a 6-year-old girl living with Rett syndrome
Meet Sarah, a 6-year-old girl living with Rett syndrome Used one word with Takes a few steps with assistance Frequent breath- meaning Constant hand Unable to use eating holding and stereotypies with utensils hyperventilation with Rarely responded to limited hand function Required assistance for posi
Slide 20: Sarah achieved sustained, meaningful functional gains
Sarah, 6-years-old at dosing, achieved sustained, meaningful functional gains Can use multiple Reaches 100% Reduced frequency of words of with meaning the time Reduced frequency breath-holding and Pulls herself to a hyperventilation of hand stereotypies Uses utensils to eat standing position and Use
Slide 21: Durable, multi-domain functional gains enabling activities of daily living
TSHA-102 delivered durable, multi-domain functional gains that enable activities of daily living Examples of functional gains observed across the 12 patients post-TSHA-102 Communication improvements Fine motor improvements Gross motor improvements Autonomic/other improvements Pre-TSHA-102 Post-TSHA-
Slide 22: Statistically significant mean R-MBA score improvement
TSHA-102 demonstrated a statistically significant mean R-MBA score improvement indicating a reversal in the disease trajectory Lower R-MBA score is associated with developmental milestone acquisition and quality of life improvement R-MBA Score Mean Change From Baseline in Patients ≥6 Years: REVEAL l
Slide 23: Early global improvement in CGI-I with dose-dependent effects
TSHA-102 demonstrated early global improvement, with dose-dependent effects that deepened over time in CGI-I 100% of Patients Demonstrated an Improved CGI-I Score of <3 at Multiple Post-treatment Visits CGI-I assesses clinician’s impression of improvement from baseline (1 = Very much improved | 7 =
Slide 24: TSHA-102 generally well-tolerated with no treatment-related SAEs or DLTs
TSHA-102 was generally well-tolerated at low and high doses with no treatment-related SAEs or DLTs Events Across the 12 Pediatric, Adolescent and Adult Patients Dosed in Part A of REVEAL Phase 1/2 Trials1 o All TEAEs considered related to TSHA-102 were mild-moderate in severity, with the most Low Do
Slide 25: FDA-aligned pathway supports potential 6-month interim registrational strategy
FDA-aligned pathway supports potential 6-month interim registrational strategy PART A: REVEAL Phase 1/2 Trials PART B: REVEAL Pivotal Trial Potential Registrational Path DOSING COMPLETE DOSING COMPLETE Developmental Plateau Population (females 6 to <22 years) Patients with Adolescent and Adult (fema
Slide 26: Robust responses at 6 and ≥12 months support potential BLA submission
Robust and clinically meaningful responses at 6 and ≥12 months support potential for BLA submission based on the 6-month interim analysis from REVEAL pivotal trial 6 Months Post-TSHA-102 12 Months Post-TSHA-102 ≥18 Months Post TSHA-102 Endpoint n=12 n=12 n=7 % of Patients Gained/Regained ≥1 Developm
Slide 27: TSHA-102 potential one-time treatment with a clear path to registration
TSHA-102 is a potential one-time treatment designed to address root cause of Rett syndrome, with a clear path to registration o No approved therapies address genetic root cause of Rett syndrome High Unmet Need and o 15,000-20,000 patients (U.S., EU+U.K.); 1 of 8,700 female births worldwide 1-3 Sign
Slide 28: Thank you
Thank you Taysha