---
schema_version: "secwatch.filing_event.v1"
accession: "0000950170-25-051575"
form_type: "8-K"
ticker: "ATOS"
cik: "0001488039"
company_name: "ATOSSA THERAPEUTICS, INC."
filed_at: "2025-04-07T23:59:59+00:00"
generated_at: "2026-05-23T19:34:34.261258+00:00"
event_type: "litigation"
sentiment: "negative"
materiality_score: 0.7
calibrated_materiality_score: 0.7
confidence: "high"
source: SEC EDGAR
---

# Intas Pharmaceuticals challenges two Atossa endoxifen patents with PGR and IPR petitions at USPTO

## Summary
- Intas filed PGR petition against U.S. Patent No. 12,071,391, titled 'Methods for Making and Using Endoxifen'.
- Intas also filed IPR petition against U.S. Patent No. 11,261,151, also titled 'Methods for Making and Using Endoxifen'.
- Atossa intends to vigorously contest the petitions and believes the patents are valid and enforceable.
- No assurance that Atossa will prevail in the USPTO proceedings.

## SEC filing metadata
- accession: 0000950170-25-051575
- form_type: 8-K
- ticker: ATOS
- cik: 0001488039
- company_name: ATOSSA THERAPEUTICS, INC.
- filed_at: 2025-04-07T23:59:59+00:00
- event_type: litigation
- sentiment: negative
- materiality_score: 0.7
- calibrated_materiality_score: 0.7
- confidence: high
- sec_items: 8.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1488039/000095017025051575/0000950170-25-051575-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1488039/000095017025051575/atos-20250407.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0000950170-25-051575
- JSON: https://secwatch.observer/filing/0000950170-25-051575.json
- Plain text: https://secwatch.observer/filing/0000950170-25-051575.txt

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