---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-23-148827"
form_type: "8-K"
ticker: "TSHA"
cik: "0001806310"
company_name: "Taysha Gene Therapies, Inc."
filed_at: "2023-05-19T23:59:59+00:00"
generated_at: "2026-06-14T19:59:53.302589+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.6
calibrated_materiality_score: 0.6
confidence: "high"
source: SEC EDGAR
---

# Taysha TSHA-102 data: safe in wild-type mice, extends survival >4x in Rett model

## Summary
- New wild-type mouse data: TSHA-102 showed no toxicity or survival reduction over 36 weeks, no impact on neurobehavioral function.
- In Mecp2–/Y knockout mice, TSHA-102 led to 47% survival at 36 weeks vs median 8.1 weeks in vehicle group (>4-fold extension, p<0.0001).
- TSHA-102 significantly delayed onset of severe Rett phenotypes: severe clasping from ~7 to 21 weeks, abnormal gait from ~8 to 20 weeks.
- Dosing of first adult patient in Phase 1/2 REVEAL trial expected Q2 2023; initial safety data anticipated Q2 2023.
- TSHA-102 uses miRARE technology to regulate MeCP2 expression, addressing risks of both under- and overexpression in mosaic X-chromosome silencing.

## SEC filing metadata
- accession: 0001193125-23-148827
- form_type: 8-K
- ticker: TSHA
- cik: 0001806310
- company_name: Taysha Gene Therapies, Inc.
- filed_at: 2023-05-19T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.6
- calibrated_materiality_score: 0.6
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1806310/000119312523148827/0001193125-23-148827-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1806310/000119312523148827/d511724d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-23-148827
- JSON: https://secwatch.observer/filing/0001193125-23-148827.json
- Plain text: https://secwatch.observer/filing/0001193125-23-148827.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.