---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-26-213439"
form_type: "8-K"
ticker: "ATOS"
cik: "0001488039"
company_name: "ATOSSA THERAPEUTICS, INC."
filed_at: "2026-05-08T23:59:59+00:00"
generated_at: "2026-05-14T21:03:34.732484+00:00"
event_type: "earnings"
sentiment: "positive"
materiality_score: 0.65
calibrated_materiality_score: 0.65
confidence: "high"
source: SEC EDGAR
---

# Operating expenses $9.9M, up 34% YoY; FDA grants RPD for (Z)-endoxifen in DMD and McCune-Albright

## Summary
- Total operating expenses $9.9M in Q1 2026, up from $7.4M in Q1 2025, driven by higher legal fees for patent litigation (subsequently settled) and R&D costs.
- R&D expenses $4.8M (+15% YoY) on increased clinical trial costs for (Z)-endoxifen; G&A $5.1M (+56%) due to $1.8M in patent litigation legal fees.
- FDA granted Orphan Drug Designation (Jan 2026) and Rare Pediatric Disease designation for (Z)-endoxifen in Duchenne Muscular Dystrophy.
- FDA granted Rare Pediatric Disease designation for (Z)-endoxifen in McCune-Albright Syndrome (May 2026), eligible for Priority Review Voucher (sold for $100-205M).
- Atossa strengthened leadership with two new Medical Directors: Dr. Puyana Theall (Breast Oncology) and Dr. Giwa (Rare Diseases).

## SEC filing metadata
- accession: 0001193125-26-213439
- form_type: 8-K
- ticker: ATOS
- cik: 0001488039
- company_name: ATOSSA THERAPEUTICS, INC.
- filed_at: 2026-05-08T23:59:59+00:00
- event_type: earnings
- sentiment: positive
- materiality_score: 0.65
- calibrated_materiality_score: 0.65
- confidence: high
- sec_items: 2.02, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1488039/000119312526213439/0001193125-26-213439-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1488039/000119312526213439/atos-20260508.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-26-213439
- JSON: https://secwatch.observer/filing/0001193125-26-213439.json
- Plain text: https://secwatch.observer/filing/0001193125-26-213439.txt

## Source-grounded claims
- claim_id: 1983a4143584a1cf12538091c9f9de4506c4ad80
  claim: ATOSSA THERAPEUTICS, INC. reported financial results for the first quarter ended March 31, 2026.
  evidence_excerpt: On May 8, 2026, Atossa Therapeutics, Inc. (the “Company”) issued a press release announcing the first quarter ended March 31, 2026 financial results and providing a Company update.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1488039/000119312526213439/0001193125-26-213439-index.htm

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