---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-25-134462"
form_type: "8-K"
ticker: "SION"
cik: "0002036042"
company_name: "Sionna Therapeutics, Inc."
filed_at: "2025-06-04T23:59:59+00:00"
generated_at: "2026-05-20T00:27:33.239851+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.7
calibrated_materiality_score: 0.7
confidence: "high"
source: SEC EDGAR
---

# Sionna reports positive Phase 1 data for NBD1 stabilizers SION-719 and SION-451; advances both to next trials

## Summary
- Both SION-719 and SION-451 were generally well tolerated with no serious adverse events or discontinuations.
- Both compounds met exposure thresholds from preclinical CFHBE model, indicating potential for clinically meaningful benefit.
- SION-719 to advance to Phase 2a proof-of-concept add-on trial in CF patients; initiation H2 2025, topline mid-2026.
- SION-451 to advance to Phase 1 dual combination trial with SION-2222 and SION-109; initiation H2 2025, topline mid-2026.
- FDA cleared IND for SION-719; first subject dosed in midazolam drug-drug interaction study.

## SEC filing metadata
- accession: 0001193125-25-134462
- form_type: 8-K
- ticker: SION
- cik: 0002036042
- company_name: Sionna Therapeutics, Inc.
- filed_at: 2025-06-04T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.7
- calibrated_materiality_score: 0.7
- confidence: high
- sec_items: 7.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/2036042/000119312525134462/0001193125-25-134462-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/2036042/000119312525134462/d944102d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-25-134462
- JSON: https://secwatch.observer/filing/0001193125-25-134462.json
- Plain text: https://secwatch.observer/filing/0001193125-25-134462.txt

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