---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-26-229610"
form_type: "8-K"
ticker: "KRRO"
cik: "0001703647"
company_name: "Korro Bio, Inc."
filed_at: "2026-05-19T11:00:17+00:00"
generated_at: "2026-05-19T11:07:37.072985+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# Korro Bio selects KRRO-111 for AATD; pre-clinical results show >90% RNA editing

## Summary
- KRRO-111 is a GalNAc-conjugated oligonucleotide delivered subcutaneously for AATD.
- In vivo editing >90% of SERPINA1 transcript, translating to ~90% repaired functional AAT protein in mouse model.
- Repeated dosing nearly eliminated active Z-protein production; pre-existing aggregates progressively cleared.
- Company plans to present additional KRRO-111 data at future scientific meeting.
- CEO noted well-capitalized position to advance both KRRO-111 and KRRO-121 toward clinical data.

## SEC filing metadata
- accession: 0001193125-26-229610
- form_type: 8-K
- ticker: KRRO
- cik: 0001703647
- company_name: Korro Bio, Inc.
- filed_at: 2026-05-19T11:00:17+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1703647/000119312526229610/0001193125-26-229610-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1703647/000119312526229610/krro-20260519.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-26-229610
- JSON: https://secwatch.observer/filing/0001193125-26-229610.json
- Plain text: https://secwatch.observer/filing/0001193125-26-229610.txt

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