Taysha Gene Therapies, Inc. Q1 FY2025 earnings call

• TSHA-102 Program Progress: Completed dosing in Part A of REVEAL Phase 1/2 trials (10 patients), with high-dose (6 patients) and low-dose (4 patients) cohorts. TSHA-102 generally well-tolerated with no treatment-related serious adverse events. - Regulatory Alignment: Obtained written alignment from FDA on key elements of Part B pivotal trial design; plan to submit Investigational New Drug (IND) amendment this quarter. - Clinical Data: Low-dose cohort in REVEAL trials showed functional gains in pediatric and adult patients with Rett syndrome, supporting FDA interactions. - Financials: R&D expenses ($15.6M Q1 2025) decreased due to GMP batch activities but increased compensation; G&A expenses ($8.2M Q1 2025) increased; net loss ($21.5M Q1 2025) decreased; cash and cash equivalents at $116.6M as of March 31, 2025.

No distinct product segments with revenue contributions mentioned; focus is on the TSHA-102 gene therapy program.

• Plan to submit IND amendment this quarter for Part B pivotal trial. - Upcoming update on pivotal trial design, Rett syndrome natural history data analysis, and REVEAL trial data during the IRSF Scientific Meeting. - Confidence in progressing toward pivotal trial and moving closer to potential Biologics License Application (BLA) submission.

• Risks associated with forward-looking statements, including actual results differing from projections, as outlined in SEC filings. - Uncertainties in clinical trial outcomes, regulatory approvals, and market acceptance of TSHA-102.

Q: What signals point to dose response in Rett syndrome?

A: Temporal aspects, metrics like R-MBA and CGI, translational data on motor/respiratory function between doses.

Q: Frame bar for success in light of regulatory feedback?

A: Natural history analysis to establish disease trajectory baseline, regulatory details alignment (trial design, primary endpoint, study population), and clinical data review.

Q: FDA feedback post protocol submission?

A: Likely minimal back and forth due to robust data provided.

Q: Primary endpoint and statistical analysis plan?

A: Objective, clinically meaningful endpoint with bias mitigation measures (video assessments, blinded raters).

Q: Part B trial site engagement?

A: Leverage existing sites trained on TSHA-102, plan to expand enrollment.

Q: Interactions with Astellas?

A: Will execute agreement as per terms, with data package on pediatric patients forthcoming.

Q: Biomarker data for MECP2?

A: Clinical measures (functional gains) serve as current biomarkers.

Q: Safety of TSHA-102?

A: No treatment-related serious adverse events to date, benefits outweigh risks.