ATOSSA THERAPEUTICS, INC.
Atossa Therapeutics, Inc. (Nasdaq: ATOS) is a clinical-stage biopharmaceutical company focused on developing innovative medicines for oncology and rare diseases with significant unmet medical need. The company's website is www.atossatherapeutics.com. From the company’s description.
Margins and return on equity change in ; everything else in percent. Fewer shares and less debt are shown plainly, not as bad news — it depends what you make of buybacks. Dotted labels explain each measure. is shown separately from the annual figures.
What ATOSSA THERAPEUTICS, INC. does
In the company’s own words
Atossa Therapeutics, Inc. (Nasdaq: ATOS) is a clinical-stage biopharmaceutical company focused on developing innovative medicines for oncology and rare diseases with significant unmet medical need. The company's website is www.atossatherapeutics.com.
The company's lead drug candidate is oral (Z)-endoxifen, a selective estrogen receptor modulator and selective estrogen receptor degrader currently in Phase 2 clinical development. (Z)-endoxifen is the most active metabolite of Tamoxifen and is substantially more potent as an estrogen receptor antagonist than Tamoxifen and other approved selective estrogen receptor modulators. Unlike Tamoxifen, which requires metabolic activation through liver enzymes, (Z)-endoxifen does not require first-pass metabolism to achieve therapeutic concentrations, making its activity independent of patient-specific metabolic variability.
Atossa is evaluating (Z)-endoxifen across multiple clinical settings within estrogen receptor positive, human epidermal growth factor receptor 2 negative breast cancer treatment, including neoadjuvant, adjuvant, and breast density reduction indications. The company is currently investigating (Z)-endoxifen in four Phase 2 trials: Karisma-(Z)-endoxifen for mammographic breast density reduction, I-SPY 2 Endocrine Optimization Pilot for neoadjuvant therapy, RECAST DCIS for ductal carcinoma in situ, and EVANGELINE for premenopausal women with breast cancer.
Beyond oncology, Atossa is exploring (Z)-endoxifen's potential in rare disease indications including Duchenne muscular dystrophy, female carriers of Duchenne and Becker muscular dystrophy, and McCune-Albright Syndrome. In December 2025 and early 2026, the company received Rare Pediatric Disease Designation and Orphan Drug Designation for (Z)-endoxifen for Duchenne muscular dystrophy treatment.
The company holds U.S. and international patents covering proprietary (Z)-endoxifen with expected patent protection through at least November 2038. As of December 31, 2025, Atossa had cash and cash equivalents of approximately $41.3 million. The company utilizes third-party contractors for manufacturing, clinical studies, and related operations, allowing it to direct resources toward research and development and commercialization activities.
Company details
- Sector
- Healthcare
- Industry
- Pharmaceutical Preparations
- Headquarters
- SEATTLE, WA
- Fiscal year end
- December
- CIK
- 1488039
- SIC
- 2834
Financial performance, year by year
Fiscal 2013–2025 · USDThe full income statement, balance sheet and cash flow for each of these years — every figure traceable to its filing — is on the Financials tab with a free account.
Who owns ATOSSA THERAPEUTICS, INC. — and what changed
Funds as of 2026Q2 · superinvestors as of 2026-06-30
Largest fund holders · ATOSSA THERAPEUTICS, INC.’s weight in each
Fund ownership is a floor, not a census — pensions, insurers and people holding shares directly are not visible here.
Fund ownership counts N-PORT filers only, so it is a floor rather than a census — pensions, insurers and direct holders are not visible here, and the remainder is not “held by individuals”.
Every fund and institutional holder, quarter by quarter, is on the Ownership tab with a free account.
Recent filings
All filings →Each filing opens into its own statements and disclosures here.
Put this business in context.
Compare this company with peers, find it in your funds and follow its financial history with your connected AI:
- “How do ATOSSA THERAPEUTICS, INC. and its peers compare on margins and cash generation over ten years?”
- “Where did five years of ATOSSA THERAPEUTICS, INC.'s earnings go — cash, debt, buybacks, reinvestment?”
- “What changed in ATOSSA THERAPEUTICS, INC.'s last four quarterly filings that the numbers alone won't show?”