---
schema_version: "secwatch.filing_event.v1"
accession: "0000950170-25-070906"
form_type: "8-K"
ticker: "MGX"
cik: "0001785279"
company_name: "Metagenomi Therapeutics, Inc."
filed_at: "2025-05-14T23:59:59+00:00"
generated_at: "2026-05-21T09:33:34.239849+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.65
calibrated_materiality_score: 0.65
confidence: "high"
source: SEC EDGAR
---

# Metagenomi presents in vivo CNS gene editing data at ASGCT; CAST integration efficiency improved >50x

## Summary
- Type II nuclease MG21-1 in single AAV achieved 69% protein knockdown in mouse motor cortex and 82% in brain via systemic delivery.
- Ultra-compact Type V nuclease MG119-28 (488 aa) achieved 64% target protein knockdown and up to 52% editing efficiency in mouse CNS.
- Type V-K CAST system engineered for >50x improvement in large gene integration efficiency vs. natural system in mammalian cells.
- In vitro, MG119-28 restored dystrophin levels >50% in DMD myocytes and achieved complete gene disruption in K562 cells.
- Platform aims to enable extrahepatic in vivo gene editing for neurological and neuromuscular disorders.

## SEC filing metadata
- accession: 0000950170-25-070906
- form_type: 8-K
- ticker: MGX
- cik: 0001785279
- company_name: Metagenomi Therapeutics, Inc.
- filed_at: 2025-05-14T23:59:59+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.65
- calibrated_materiality_score: 0.65
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1785279/000095017025070906/0000950170-25-070906-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1785279/000095017025070906/mgx-20250514.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0000950170-25-070906
- JSON: https://secwatch.observer/filing/0000950170-25-070906.json
- Plain text: https://secwatch.observer/filing/0000950170-25-070906.txt

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