Atossa Therapeutics Reports Fourth Quarter and Year-End 2025 Financial Results and Provides a Corporate Update
Rhea-AI Summary
Atossa Therapeutics (NASDAQ: ATOS) reported 2025 year-end results and corporate updates on March 25, 2026. Key regulatory milestones include FDA Rare Pediatric Disease designation (Dec 2025) and Orphan Drug designation (Jan 2026) for (Z)-endoxifen in Duchenne Muscular Dystrophy. Total operating expenses were $37.1 million in 2025 versus $27.6 million in 2024, driven by higher R&D and G&A costs.
The company highlighted peer-reviewed publication, clinical award recognition, new clinical hires, and increased clinical trial spending to advance (Z)-endoxifen across oncology and rare-disease programs.
Positive
- FDA Rare Pediatric Disease designation for (Z)-endoxifen (December 2025)
- FDA Orphan Drug designation for (Z)-endoxifen for DMD (January 2026)
- Research and Development Expense increased to $21.185M supporting trials
- Awarded 2025 Clinical Trials Arena R&D Excellence in Precision Endocrine Therapy
- Added two medical directors to strengthen clinical leadership
Negative
- Total operating expenses rose to $37.1M in 2025 from $27.6M in 2024 (34% increase)
- Research and development expenses increased 50% year-over-year to $21.185M
- Clinical and non-clinical trial spending grew 60% to $16.204M
- General and administrative expenses rose 18% to $15.956M driven by legal fees (+$1.8M)
- Interest income declined by $1.7M due to lower invested funds
Key Figures
Market Reality Check
Peers on Argus
ATOS is down 1.63% while momentum data only flags peer SPRO moving 2.49% in the opposite (upward) direction, suggesting today’s move is stock-specific rather than part of a broader biotech shift.
Previous Earnings Reports
| Date | Event | Sentiment | Move | Catalyst |
|---|---|---|---|---|
| Nov 12 | Q3 2025 earnings | Neutral | -1.7% | Higher Q3 operating expenses and planning for Phase 2 metastatic breast cancer study. |
| Aug 12 | Q2 2025 earnings | Positive | +1.2% | Positive FDA feedback and strong I-SPY2 data with rising R&D investment. |
| May 13 | Q1 2025 earnings | Positive | +6.3% | Strategic focus on (Z)-endoxifen, strong cash balance and higher R&D spend. |
| Mar 25 | FY 2024 results | Positive | -3.3% | Full-year 2024 results with lower operating expenses and positive Phase 2 data. |
| Nov 12 | Q3 2024 earnings | Positive | -7.4% | Q3 2024 update with strong KARISMA and I-SPY2 outcomes and lower expenses. |
Earnings and full-year updates have often been fundamentally positive but met with mixed to negative next-day moves, indicating a pattern of cautious market reactions to Atossa’s spending and strategy updates.
Across the last five earnings events from Nov 2024 through Nov 2025, Atossa repeatedly highlighted (Z)-endoxifen progress, including positive Phase 2 data, strategic focus on metastatic breast cancer, and later FDA feedback clearing a Q4 2025 IND path. R&D spending has trended higher while operating expenses sometimes declined year-on-year. Share-price reactions were mixed, with both gains and notable declines, showing that stronger clinical narratives did not consistently translate into positive short-term price moves.
Historical Comparison
In the past five earnings-related releases, ATOS moved on average -0.97%. Today’s -1.63% pre-news move is modestly more negative but generally consistent with its typical earnings-day behavior.
Earnings updates show a progression from Phase 2 breast cancer data and reduced 2024 expenses toward intensified 2025 (Z)-endoxifen investment, FDA feedback enabling an IND, and expanding into rare-disease indications.
Market Pulse Summary
This announcement combines higher 2025 operating expenses of $37.1M and a wider $34.8M net loss with regulatory progress for (Z)-endoxifen, including FDA Rare Pediatric Disease and Orphan Drug designations in DMD. Cash of $41.3M at year-end 2025 provides some runway but sits against rising R&D and legal costs. Investors may watch future earnings for expense trends, cash usage, and milestones in both breast cancer and rare-disease programs.
Key Terms
rare pediatric disease designation regulatory
orphan drug designation regulatory
priority review voucher regulatory
selective estrogen receptor modulator/degrader (serm/d) medical
nf-κb medical
AI-generated analysis. Not financial advice.
"While we have consistently made meaningful and measurable progress across our (Z)-endoxifen development strategy in oncology over the last 12 months, we continue to explore the best opportunities to leverage the technology where it may help to address serious health conditions and unmet medical needs. As we continue to keep a careful eye on opportunities in the breast cancer space, we are also diligently working to advance (Z)-endoxifen in certain rare disease indications, such as Duchenne Muscular Dystrophy (DMD) and McCune-Albright Syndrome (MAS)," stated Dr. Steven Quay, M.D., Ph.D., Atossa Therapeutics' President and Chief Executive Officer. "To date, we have published work that identifies the opportunity for (Z)-endoxifen, while achieving both FDA Rare Pediatric Disease and Orphan Drug designations. We believe these FDA designations are important for future development as they both help to speed the FDA review process as well as provide potential financial benefits in the future."
"In the meantime, we are consciously aligning our resources with the demands of potential commercialization, even as we have added new professionals to our team to help drive both our rare disease and breast cancer programs forward. With a strong balance sheet and a strategically focused team, we believe we are well-positioned to execute and advance our clinical programs toward key value-creating milestones," concluded Dr. Quay.
Clinical & Regulatory Progress & Announcements
- Atossa Highlighted Emerging Opportunity for (Z)-Endoxifen in Duchenne Muscular Dystrophy, Including Symptomatic Female Carriers, Following Peer-Reviewed Publication and Scientific Presentation - The published article, "A Hypothesized Therapeutic Role of (Z)-Endoxifen in Duchenne Muscular Dystrophy (DMD)," surveys the DMD treatment landscape and details how (Z)-endoxifen's pharmacology could address multiple downstream drivers of disease, including inflammation, fibrosis, calcium dysregulation, mitochondrial dysfunction, and lipid abnormalities. The paper emphasizes (Z)-endoxifen's direct estrogen-receptor (ER) modulation, allosteric inhibition of PKC (notably PKC-β1), and effects along AKT/mTOR and NF-κB axes, mechanisms that together may help slow disease progression when used as an adjunct to standard care. Notably, the authors underscore (Z)-endoxifen's potential to deliver more consistent therapeutic exposures than tamoxifen by bypassing CYP2D6 metabolic variability, an important limitation of the pro-drug approach. As illustrated in the mechanistic diagram, page 7 of the publication, the paper maps (Z)-endoxifen's ER-dependent and ER-independent signaling effects relevant to dystrophic muscle.
- Atossa Therapeutics Received FDA Rare Pediatric Disease Designation for (Z)-Endoxifen for Duchenne Muscular Dystrophy - In December 2025, Atossa announced that the
U.S. Food and Drug Administration ("FDA") granted Rare Pediatric Disease ("RPD") designation to (Z)-endoxifen for the treatment of DMD. RPD designation is granted to drug candidates intended to treat serious or life-threatening diseases that primarily affect individuals from birth to 18 years of age. Upon approval of a qualifying marketing application, drugs with RPD designation may be eligible for a Priority Review Voucher ("PRV"), which can be used to obtain priority review for a future application or may be sold or transferred to another sponsor. In the last 18–24 months, disclosed PRV sales have ranged from$100 –$200 million .
- Atossa Therapeutics Won the 2025 Clinical Trials Arena Research and Development Excellence Award in Precision Endocrine Therapy Category - In December 2025, Atossa announced that it had been selected as a winner of the 2025 Clinical Trials Arena Excellence Awards. The Company was honored with the Research and Development Award in the Precision Endocrine Therapy category. Atossa earned this recognition for its innovative work advancing (Z)-endoxifen, its lead precision-engineered endocrine therapy. (Z)-endoxifen is a potent selective estrogen receptor modulator/degrader (SERM/D) with additional PKCβ1 inhibition, designed to provide consistent systemic exposure independent of CYP2D6 metabolism. The therapy is being evaluated across metastatic, neoadjuvant, adjuvant, and breast cancer risk-reduction settings, with an emerging application in DMD.
- Atossa Therapeutics Received FDA Orphan Drug Designation for (Z)-Endoxifen for the Treatment of Duchenne Muscular Dystrophy - In January 2026, Atossa announced that the
U.S. Food and Drug Administration ("FDA") Office of Orphan Products Development ("OOPD") granted Orphan Drug Designation to (Z)-endoxifen for the treatment of DMD. Orphan Drug Designation is granted by FDA to therapies intended to treat rare diseases or conditions. The designation is designed to encourage drug development by offering certain potential incentives, such as regulatory support and, if the product ultimately receives marketing approval for the designated indication, eligibility for a period of market exclusivity.
Atossa Announces Additions to Management Team
- Atossa Therapeutics Strengthened Clinical Leadership Team with the Addition of Two Experienced Biopharma Executives - Atossa announced the engagement of Kathy Puyana Theall, M.D., as Medical Director - Breast Oncology, and Adebola Giwa, M.D., as Medical Director - Rare Diseases. We believe the addition of these two highly experienced physicians and clinical leaders meaningfully strengthens Atossa's ability to execute on its (Z)-endoxifen development strategy across both breast cancer and rare disease programs, including DMD and MAS, as the Company advances toward key clinical and regulatory milestones.
Comparison of Years-Ended December 31, 2025 and 2024
Operating Expenses. Total operating expenses were
Research & Development Expenses. The following table provides a breakdown of major categories within R&D expenses for the years ended December 31, 2025 and 2024, together with the dollar change in those categories (dollars in thousands):
For the Year Ended December 31, | ||||
2025 | 2024 | Increase | Increase (%) | |
Research and Development Expense | ||||
Clinical and non-clinical trials | 60 % | |||
Compensation | 3,206 | 2,928 | 278 | 9 % |
Professional fees and other | 1,775 | 1,082 | 693 | 64 % |
Research and Development Expense Total | 50 % | |||
As (Z)-endoxifen is our only product candidate for which we currently incur R&D expenses, we have not further disaggregated R&D expenses by product candidate:
- Clinical and pre-clinical trial expense increased
$6.1 million
- The increase in R&D compensation expense of
$0.3 million $0.4 million $0.1 million
- The increase in R&D professional fees and other of
$0.7 million
General and Administrative (G&A) Expenses. The following table provides a breakdown of major categories within G&A expenses for the years ended December 31, 2025 and 2024, together with the dollar change in those categories (dollars in thousands):
For the Year Ended December 31, | ||||
2025 | 2024 | Increase | Increase (%) | |
General and Administrative Expense | ||||
Compensation | 11 % | |||
Professional fees and other | 9,191 | 7,164 | 2,027 | 28 % |
Insurance | 703 | 882 | (179) | (20) % |
General and Administrative Expense Total | 18 % | |||
- The increase in G&A compensation expense of
$0.6 million $0.2 million $0.4 million $0.4 million
- G&A professional fees and other expenses increased by
$2.0 million $1.8 million $1.6 million $0.3 million $0.3 million
- The decrease in G&A insurance expense of
$0.2 million
Interest Income. Interest income of
Impairment Charge on Investment in Equity Securities. For the year ended December 31, 2024, we wrote down our Investment in equity securities by
About (Z)-Endoxifen
(Z)-Endoxifen is a potent Selective Estrogen Receptor Modulator/Degrader (SERM/D) with demonstrated activity across multiple mechanisms of interest. Atossa is evaluating its potential applications in oncology and rare diseases. The Company's proprietary oral formulation has shown a favorable safety profile and pharmacology distinct from tamoxifen, including ER-targeted effects and PKC inhibition. Atossa's (Z)-endoxifen is not approved for any indication.
Atossa's (Z)-endoxifen program is supported by a growing global intellectual property portfolio, including multiple recently issued
About Atossa Therapeutics
Atossa Therapeutics, Inc. (Nasdaq: ATOS) is a clinical-stage biopharmaceutical company developing innovative medicines in oncology and other areas of significant unmet need. The Company's lead product candidate, (Z)-endoxifen, is currently in development across several clinical settings. More information is available at https://atossatherapeutics.com.
Forward Looking Statements
This press release contains certain "forward-looking statements" within the meaning of applicable securities laws, including but not limited to, our 2026 outlook and our expectations regarding the Company's development and regulatory strategy and related milestones, including potential Investigational New Drug submissions, the potential indications that the Company may pursue for (Z)-endoxifen, the potential for (Z)-endoxifen to receive regulatory approval and the timing thereof, the Company's progress across its pipeline and potential commercialization, the strength of the Company's patent portfolio, the Company's potential eligibility for the Rare Pediatric Disease Priority Review Voucher (PRV) program and the value of a PRV, and the potential market and growth opportunities for the Company. Words such as "expect," "potential," "continue," "may," "will," "should," "could," "would," "seek," "intend," "plan," "estimate," "anticipate," "believe," "design," "predict," "future," or other similar expressions or statements regarding intent, belief or current expectations, are forward-looking statements.
Forward-looking statements in this press release are subject to risks and uncertainties that may cause actual results, outcomes, or the timing of actual results or outcomes to differ materially from those projected or anticipated, including, without limitation, risks and uncertainties associated with: our ability to successfully execute our strategy to shorten our clinical development timelines and pursue a DMD indication or other indications for our lead program, (Z)-endoxifen; expected timing, completion and results of our preclinical studies, clinical trials and research and development programs; the unpredictable relationship between preclinical study results and clinical study results; the timing or likelihood of regulatory filings and approvals; the outcome or timing of necessary regulatory approvals; our ability to receive orphan-drug exclusivity for (Z)-endoxifen for DMD; our ability to maintain compliance with Nasdaq listing requirements; our ability to establish and maintain intellectual property rights covering our products; the impact of general macroeconomic conditions on our business; our ability to raise capital; and other risks and uncertainties detailed from time to time in Atossa's filings with the SEC, including, without limitation, its Annual Reports on Form 10-K and Quarterly Reports on Form 10-Q.
Forward-looking statements are presented as of the date of this press release. Except as required by law, we do not intend to update any forward-looking statements.
ATOSSA THERAPEUTICS, INC. | ||||
December 31, 2025 | December 31, 2024 | |||
Assets | ||||
Current assets | ||||
Cash and cash equivalents | $ | 41,299 | $ | 71,084 |
Restricted cash | 110 | 110 | ||
Prepaid materials | 3,081 | 2,098 | ||
Prepaid expenses and other current assets | 1,128 | 1,165 | ||
Total current assets | 45,618 | 74,457 | ||
Other assets | 1,990 | 1,987 | ||
Total assets | $ | 47,608 | $ | 76,444 |
Liabilities and stockholders' equity | ||||
Current liabilities | ||||
Accounts payable | $ | 4,293 | $ | 679 |
Accrued expenses | 1,307 | 919 | ||
Payroll liabilities | 1,558 | 1,862 | ||
Other current liabilities | 1,097 | 1,507 | ||
Total current liabilities | 8,225 | 4,967 | ||
Total liabilities | 8,225 | 4,967 | ||
Commitments and contingencies | ||||
Stockholders' equity | ||||
Convertible preferred stock - | — | — | ||
Common stock - | 1,550 | 1,550 | ||
Additional paid-in capital | 285,840 | 283,194 | ||
Treasury stock, at cost; 88,003 shares of common stock at December 31, 2025 | (1,475) | (1,475) | ||
Accumulated deficit | (246,562) | (211,792) | ||
Total stockholders' equity | 39,353 | 71,477 | ||
Total liabilities and stockholders' equity | $ | 47,608 | $ | 76,444 |
ATOSSA THERAPEUTICS, INC. | ||
For the Year Ended December 31, | ||
2025 | 2024 | |
Operating expenses | ||
Research and development | $ 21,185 | $ 14,117 |
General and administrative | 15,956 | 13,504 |
Total operating expenses | 37,141 | 27,621 |
Operating loss | (37,141) | (27,621) |
Impairment charge on investment in equity securities | — | (1,710) |
Interest income | 2,377 | 4,050 |
Other expense, net | (6) | (223) |
Loss before income taxes | (34,770) | (25,504) |
Income tax benefit | — | — |
Net loss | $ (34,770) | $ (25,504) |
Net loss per share of common stock - basic and diluted | $ (4.04) | $ (3.04) |
Weighted average shares outstanding used to compute net loss per share - basic and diluted | 8,611,321 | 8,6390,618 |
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SOURCE Atossa Therapeutics Inc
FAQ
What did Atossa Therapeutics (ATOS) announce on March 25, 2026 about (Z)-endoxifen?
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