Atossa Therapeutics Announces Issuance of U.S. Patent Covering Enteric Oral (Z)-Endoxifen Formulations and Methods of Treating Patients Using (Z)-Endoxifen

Rhea-AI Summary

Atossa Therapeutics (Nasdaq: ATOS) announced that the USPTO issued U.S. Patent No. 12,479,790 B2 on Dec 9, 2025, titled "Methods for Making and Using Endoxifen."

The patent includes 100 claims covering enteric oral formulations of highly pure (Z)-endoxifen free base, specific solid oral dosage forms, scalable manufacturing processes, and methods of use for hormone-dependent breast disorders and other estrogen-related conditions. The company says this grant adds to its existing U.S. patents and worldwide applications to support late-stage trials and potential commercialization of (Z)-endoxifen across prevention and treatment settings.

Positive

• U.S. Patent No. 12,479,790 B2 issued on Dec 9, 2025
• 100 claims covering enteric oral (Z)-endoxifen formulations and methods
• Patent covers scalable manufacturing processes for (Z)-endoxifen
• Claims include specific stable solid oral dosage forms with sustained exposure

Negative

• None.

Key Figures

Patent claims 100 claims New U.S. Patent No. 12,479,790 B2 for (Z)-endoxifen formulations and uses

Q3 2025 net loss $8.7M Net loss reported in 10-Q for Q3 2025

Loss per share $0.07 Q3 2025 loss per share from 10-Q

Operating expenses $9.3M Q3 2025 operating expenses in 10-Q

Cash & equivalents $51.8M Cash and cash equivalents as of Q3 2025

ATM facility size $100.0M At-the-market facility capacity with no 2025 sales to date

Shares outstanding 129,171,424 Shares outstanding as of November 1, 2025

Short-term net loss $23.8M Net loss for nine months ended Q3 2025 from 10-Q

Market Reality Check

$0.8087 Last Close

Volume Volume 455,929 is below the 20-day average of 591,494, suggesting limited pre-news positioning. normal

Technical Shares at 0.7816 are trading below the 200-day MA of 0.82 and 39.79% under the 52-week high.

Peers on Argus

Peers show mixed moves with modest magnitude: ANRO up 0.07%, SPRO up 0.87%, while MGNX is down 5%. No clear sector-wide trend aligns with ATOS’s -2.21% move.

Historical Context

Date	Event	Sentiment	Move	Catalyst
Dec 04	Regulatory strategy	Positive	+2.7%	FDA Type C feedback clarified expedited paths for (Z)-endoxifen programs.
Dec 02	AI research update	Positive	-5.7%	AI-driven study suggested (Z)-endoxifen potential in glioblastoma.
Nov 17	New indication focus	Positive	-1.9%	(Z)-endoxifen highlighted as a candidate for DMD and female carriers.
Nov 12	Quarterly earnings	Negative	-1.7%	Q3 2025 showed higher operating expenses and widening net loss.
Nov 06	Conference abstracts	Positive	-1.6%	Four (Z)-endoxifen posters accepted for presentation at SABCS 2025.

Pattern Detected

Recent (Z)-endoxifen news, including regulatory strategy and new indications, has often been followed by modest, mixed price reactions, with several positive updates seeing flat-to-negative moves.

Recent Company History

Over the last month, ATOS has focused on advancing (Z)-endoxifen across multiple fronts. A Nov 12 earnings update highlighted rising R&D spend and patent challenges, followed by scientific visibility at SABCS 2025 on Nov 6. Subsequent news on DMD, glioblastoma, and, on Dec 4, an accelerated FDA strategy for breast cancer showed expanding indications and clearer regulatory pathways. Today’s U.S. patent issuance fits this pattern of building a broader, protected franchise around endoxifen.

Market Pulse Summary

This announcement adds a U.S. patent with 100 claims covering enteric oral (Z)-endoxifen formulations, dosage forms, and methods of use across hormone-driven breast conditions. It builds on earlier patents and the ongoing Phase 2 EVANGELINE trial and metastatic plans, reinforcing Atossa’s IP position around its lead asset. Against a backdrop of continued losses, including a Q3 2025 net loss of $8.7M, investors may watch how this IP supports late-stage trials and future partnering or commercialization.

Key Terms

uspto regulatory

"the United States Patent and Trademark Office (USPTO) issued U.S. Patent No."

United States Patent and Trademark Office (USPTO) is the federal agency that reviews and issues patents for inventions and registers trademarks for brand names and logos. For investors, USPTO decisions act like a gatekeeper for a company’s legal right to exclude competitors — similar to a property deed for ideas and brands — which can protect revenue, support pricing power, and affect a company’s long‑term value and risk profile.

enteric oral formulations medical

"claims directed to enteric oral formulations of highly pure (Z)-endoxifen free base"

Enteric oral formulations are pill or capsule products designed with a protective coating that prevents a drug from dissolving in the acidic stomach and instead releases it once it reaches the gentler environment of the intestines. For investors, this matters because such formulations can improve a drug’s effectiveness, reduce side effects, extend patent life, and add manufacturing or regulatory complexity that affects development cost, time to market, and potential commercial value.

systemic exposure medical

"stable formulations providing therapeutically meaningful and sustained systemic exposure"

Systemic exposure refers to the level of risk that an individual or organization faces from potential problems within the entire financial system. It is like the amount of water in a boat that could be affected if the boat’s hull develops a leak; the more exposed, the greater the potential impact from widespread issues. Understanding systemic exposure helps investors gauge how vulnerable they might be to large-scale financial disruptions.

metastatic breast cancer medical

"Metastatic breast cancer (MBC): A dose-ranging study is in preparation"

Metastatic breast cancer is breast cancer that has spread beyond the breast and nearby lymph nodes to other organs, such as bones, liver, lungs or brain. For investors it matters because these advanced-stage cases often require long-term, complex and costly treatments, drive demand for specialty drugs and diagnostics, and influence regulatory approvals, pricing negotiations and the long-term revenue potential of companies developing therapies aimed at slowing spread or improving quality of life. An everyday analogy: it’s like a weed that has taken root in multiple beds rather than just one garden patch, requiring broader and more sustained effort to manage.

neoadjuvant medical

"Neoadjuvant ER+/HER2- breast cancer: Enrollment and data generation continue"

"Neoadjuvant" describes treatments or interventions that are given before the main or primary procedure, such as surgery or a major decision. It’s like preparing the ground before planting seeds, aiming to improve the final outcome. For investors, understanding neoadjuvant approaches can provide insight into how companies enhance results or effectiveness in their processes or products.

er+/her2- medical

"Neoadjuvant ER+/HER2- breast cancer: Enrollment and data generation continue"

ER+/HER2- describes a type of breast cancer where the cancer cells grow in response to the hormone estrogen (ER positive) but do not have excess levels of the HER2 protein (HER2 negative). This classification helps determine the most effective treatments and can influence prognosis. For investors, understanding such medical details can signal potential shifts in healthcare demand and the development of targeted therapies.

phase 2 medical

"data generation continue in the Phase 2 EVANGELINE trial."

Phase 2 is the mid-stage clinical trial where a new drug or treatment is tested in a larger group of patients to see if it works and to keep checking safety after initial human testing. Think of it as a field test that proves whether a product actually delivers its promised benefit. Investors watch Phase 2 closely because its results strongly influence a medicine’s chances of reaching the market, the size of its potential sales, and the company’s valuation.

AI-generated analysis. Not financial advice.

New patent further strengthens global intellectual property estate supporting Atossa's lead program across the breast cancer spectrum and other hormone-driven conditions

SEATTLE, Dec. 9, 2025 /PRNewswire/ -- Atossa Therapeutics, Inc. (Nasdaq: ATOS) ("Atossa" or the "Company"), a clinical-stage biopharmaceutical company developing innovative therapies in areas of significant unmet need in breast cancer, today announced that the United States Patent and Trademark Office (USPTO) issued U.S. Patent No. 12,479,790 B2, titled, "Methods for Making and Using Endoxifen."

The newly issued patent includes 100 claims directed to enteric oral formulations of highly pure (Z)-endoxifen free base, as well as methods of using those compositions to treat a range of hormone-dependent breast disorders and other estrogen-related conditions. The patent also covers specific solid oral dosage forms and stable formulations providing therapeutically meaningful and sustained systemic exposure to (Z)-endoxifen.

"We believe this patent meaningfully extends and reinforces our already robust endoxifen patent estate," said Steven Quay, M.D., Ph.D., Atossa's President and Chief Executive Officer. "By covering both scalable manufacturing processes and key methods of use, this patent supports our long-term strategy to position (Z)-endoxifen as a differentiated therapy across the breast cancer spectrum, from risk-reduction and neoadjuvant treatment through adjuvant and metastatic disease, while also enabling opportunities in other hormone-driven conditions.

 "Together with previously issued U.S. patents covering storage-stable and sustained-release endoxifen formulations, and broader formulation patents granted earlier this year, this new patent further consolidates our leadership position in endoxifen therapeutics. A strong and durable intellectual property foundation is essential as we invest in late-stage clinical trials and potential future commercialization," concluded Dr. Quay.

Atossa is currently advancing its proprietary (Z)-endoxifen in multiple clinical settings, including:

• Metastatic breast cancer (MBC): A dose-ranging study is in preparation as part of the Company's strategy to support registrational development.
• Neoadjuvant ER+/HER2- breast cancer: Enrollment and data generation continue in the Phase 2 EVANGELINE trial.
• Breast cancer risk-reduction: Development includes a low-dose strategy targeting mammographic breast density and overall breast cancer risk.

The Company's growing patent portfolio, which now includes multiple issued U.S. patents and corresponding applications worldwide, is intended to provide long-term exclusivity for (Z)-endoxifen formulations, manufacturing processes, and key therapeutic uses in breast cancer treatment and risk reduction.

About U.S. Patent No. 12,479,790

U.S. Patent No. 12,479,790 B2, "Methods for Making and Using Endoxifen," is assigned to Atossa Therapeutics, Inc. The patent has 100 claims directed to enteric oral formulations of highly pure (Z)-endoxifen free base, as well as methods of using those compositions to treat a range of hormone-dependent breast disorders and other estrogen-related conditions. The patent also covers specific solid oral dosage forms and stable formulations providing therapeutically meaningful and sustained systemic exposure to (Z)-endoxifen.

About (Z)-Endoxifen

(Z)-endoxifen is one of the most potent selective estrogen receptor modulators (SERMs) for estrogen receptor inhibition and may also promote estrogen receptor degradation. It has demonstrated activity in settings where tumors have developed resistance to other hormonal therapies and has been shown to target PKCβ1, a known oncogenic protein, at clinically achievable concentrations. Atossa continues to optimize its proprietary oral formulation of (Z)-endoxifen, which is designed to minimize stomach exposure and maintain the active Z-isomer, and ensures consistent systemic exposure across a range of breast cancer prevention and treatment indications.

About Atossa Therapeutics

Atossa Therapeutics, Inc. (Nasdaq: ATOS) is a clinical-stage biopharmaceutical company developing innovative therapies in areas of significant unmet need in breast cancer. The Company's lead product candidate, (Z)-endoxifen, is being developed as a highly potent SERM for use across the breast cancer continuum of care. For more information, please visit www.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 expectations regarding the Company's development and regulatory strategy and related milestones, the potential indications that the Company may pursue for (Z)-endoxifen, the potential for (Z)-endoxifen to receive regulatory approval and timing thereof, the strength of the Company's patent portfolio, 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 metastatic breast cancer 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 regain and 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.

 

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SOURCE Atossa Therapeutics Inc

FAQ

What did Atossa (ATOS) announce on December 9, 2025 regarding patents?

Atossa announced the USPTO issued U.S. Patent No. 12,479,790 B2 covering enteric oral (Z)-endoxifen formulations and methods.

How many claims does Atossa's U.S. patent for (Z)-endoxifen include?

The patent includes 100 claims directed to enteric oral formulations, dosage forms, manufacturing, and methods of use.

Which uses does the Atossa (ATOS) patent cover for (Z)-endoxifen?

The patent covers methods of using (Z)-endoxifen to treat a range of hormone-dependent breast disorders and other estrogen-related conditions.

Does the new Atossa patent address manufacturing of (Z)-endoxifen?

Yes; the patent explicitly covers scalable manufacturing processes for highly pure (Z)-endoxifen free base.

How does the patent affect Atossa's clinical programs for (Z)-endoxifen?

The company says the patent strengthens its IP estate to support late-stage clinical trials and potential commercialization across prevention and treatment settings.