---
schema_version: "secwatch.filing_event.v1"
accession: "0001437749-23-024896"
form_type: "8-K"
ticker: "ATOS"
cik: "0001488039"
company_name: "ATOSSA THERAPEUTICS, INC."
filed_at: "2023-08-31T23:59:59+00:00"
generated_at: "2026-06-11T01:07:40.075146+00:00"
event_type: "litigation"
sentiment: "negative"
materiality_score: 0.6
calibrated_materiality_score: 0.6
confidence: "high"
source: SEC EDGAR
---

# Intas Pharmaceuticals files PGR petition challenging Atossa's endoxifen patent

## Summary
- Intas Pharmaceuticals filed a Post-Grant Review petition with USPTO challenging Atossa's U.S. Patent No. 11,572,334.
- Patent covers methods for making and using endoxifen.
- Atossa intends to contest the PGR and believes the patent is valid and enforceable.
- No assurance of prevailing; Intas will be estopped from raising certain arguments in future litigation.

## SEC filing metadata
- accession: 0001437749-23-024896
- form_type: 8-K
- ticker: ATOS
- cik: 0001488039
- company_name: ATOSSA THERAPEUTICS, INC.
- filed_at: 2023-08-31T23:59:59+00:00
- event_type: litigation
- sentiment: negative
- materiality_score: 0.6
- calibrated_materiality_score: 0.6
- confidence: high
- sec_items: 8.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1488039/000143774923024896/0001437749-23-024896-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1488039/000143774923024896/atos20230830_8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001437749-23-024896
- JSON: https://secwatch.observer/filing/0001437749-23-024896.json
- Plain text: https://secwatch.observer/filing/0001437749-23-024896.txt

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