---
schema_version: "secwatch.filing_event.v1"
accession: "0001104659-26-072633"
form_type: "8-K"
ticker: "TOVX"
cik: "0000894158"
company_name: "Theriva Biologics, Inc."
filed_at: "2026-06-11T12:10:25+00:00"
generated_at: "2026-06-11T12:15:56.535902+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.8
calibrated_materiality_score: 0.8
confidence: "high"
source: SEC EDGAR
---

# Theriva Biologics announces VCN-01 Phase 1 HNSCC data showing median OS up to 17.3 months

## Summary
- Median OS 10.3-17.3 months across three arms in heavily pre-treated, immunotherapy-refractory HNSCC patients.
- Median PFS 1.6-3.7 months; best PFS (3.7 mo) in sequential low-dose VCN-01 arm (Arm II LD).
- Biomarker data confirms VCN-01 mechanism: increased PH20, viral replication, CD8+ T cell infiltration, PD-L1 upregulation.
- Results published online in Clinical Cancer Research; trial NCT03799744 enrolled 20 patients.
- Data suggest VCN-01 can resensitize refractory tumors to checkpoint inhibitor durvalumab.

## SEC filing metadata
- accession: 0001104659-26-072633
- form_type: 8-K
- ticker: TOVX
- cik: 0000894158
- company_name: Theriva Biologics, Inc.
- filed_at: 2026-06-11T12:10:25+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.8
- calibrated_materiality_score: 0.8
- confidence: high
- sec_items: 7.01, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/894158/000110465926072633/0001104659-26-072633-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/894158/000110465926072633/tm2617564d1_8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001104659-26-072633
- JSON: https://secwatch.observer/filing/0001104659-26-072633.json
- Plain text: https://secwatch.observer/filing/0001104659-26-072633.txt

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