---
schema_version: "secwatch.filing_event.v1"
accession: "0001628280-25-049246"
form_type: "8-K"
ticker: "SION"
cik: "0002036042"
company_name: "Sionna Therapeutics, Inc."
filed_at: "2025-11-05T23:59:59+00:00"
generated_at: "2026-05-17T00:26:14.488567+00:00"
event_type: "earnings"
sentiment: "positive"
materiality_score: 0.7
calibrated_materiality_score: 0.7
confidence: "high"
source: SEC EDGAR
---

# Sionna Q3 net loss $20.3M; starts Phase 2a trial for SION-719; cash runway into 2028

## Summary
- Net loss of $20.3M in Q3 2025 versus $25.4M in Q3 2024; R&D expenses fell to $16.0M from $24.6M due to prior year license charge.
- Cash and equivalents totaled $325.0M as of Sep 30, 2025, expected to fund operations into 2028.
- Initiated PreciSION CF Phase 2a proof-of-concept trial for SION-719 as add-on to standard of care in cystic fibrosis; topline data expected in mid-2026.
- Initiated Phase 1 trial evaluating SION-451 in proprietary dual combinations with CFTR correctors SION-2222 and SION-109; topline data mid-2026.
- Appointed Caroline Stark Beer as Chief Business Officer in September 2025.

## SEC filing metadata
- accession: 0001628280-25-049246
- form_type: 8-K
- ticker: SION
- cik: 0002036042
- company_name: Sionna Therapeutics, Inc.
- filed_at: 2025-11-05T23:59:59+00:00
- event_type: earnings
- sentiment: positive
- materiality_score: 0.7
- calibrated_materiality_score: 0.7
- confidence: high
- sec_items: 2.02, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/2036042/000162828025049246/0001628280-25-049246-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/2036042/000162828025049246/sion-20251105.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001628280-25-049246
- JSON: https://secwatch.observer/filing/0001628280-25-049246.json
- Plain text: https://secwatch.observer/filing/0001628280-25-049246.txt

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