# EDGAR Filing Document

**Accession Number:** 0001488039
**File Stem:** 0001193125-26-003506
**Filing Date:** 2026-1
**Character Count:** 9387
**Document Hash:** 6a27d8ae42b04db0c53b05bc6d0adf1f
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-26-003506.hdr.sgml**: 20260106

**ACCESSION NUMBER**: 0001193125-26-003506

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 12

**CONFORMED PERIOD OF REPORT**: 20260106

**ITEM INFORMATION**: Other Events

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20260106

**DATE AS OF CHANGE**: 20260106

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** ATOSSA THERAPEUTICS, INC.
- **CENTRAL INDEX KEY:** 0001488039
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 264753208
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 8-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-35610
- **FILM NUMBER:** 26509488

**BUSINESS ADDRESS:**
- **STREET 1:** 1448 NW MARKET STREET
- **STREET 2:** SUITE 500
- **CITY:** SEATTLE
- **STATE:** WA
- **ZIP:** 98107
- **BUSINESS PHONE:** 206.588.0256

**MAIL ADDRESS:**
- **STREET 1:** 1448 NW MARKET STREET
- **STREET 2:** SUITE 500
- **CITY:** SEATTLE
- **STATE:** WA
- **ZIP:** 98107

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** ATOSSA GENETICS INC
- **DATE OF NAME CHANGE:** 20100325

?xml version='1.0' encoding='ASCII'? 8-K

**UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549**

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**FORM** 8-K

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**CURRENT REPORT**

**Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934**

**Date of Report (Date of earliest event reported):** January 6, 2026<br>

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Atossa Therapeutics, Inc.

**(Exact name of Registrant as Specified in Its Charter)**

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| | | |
|:---|:---|:---|
| Delaware | 001-35610 | 26-4753208 |
| **(State or Other Jurisdiction<br>of Incorporation)** | **(Commission File Number)** | **(IRS Employer<br>Identification No.)** |
| 1448 NW Market Street, Suite 500 |  |  |
| Seattle**,** Washington |  | 98107 |
| **(Address of Principal Executive Offices)** |  | **(Zip Code)** |

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**Registrant's Telephone Number, Including Area Code: (**206**)** 588-0256<br>

**N/A**<br>

**(Former Name or Former Address, if Changed Since Last Report)**

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Check th e appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

**Securities registered pursuant to Section 12(b) of the Act:**

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| | | |
|:---|:---|:---|
| **<br>Title of each class** | **Trading<br>Symbol(s)** | **<br>Name of each exchange on which registered** |
| Common Stock, $0.18 par value | ATOS | The Nasdaq Capital Market |

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Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☐

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If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

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**Item 8.01 Other Events**

On January 6, 2026, Atossa Therapeutics, Inc. (the "Company") issued a press release announcing that the U.S. Food and Drug Administration ("FDA") issued a "Study May Proceed" letter for the Company's study of metastatic breast cancer.

A copy of the press release is filed as Exhibit 99.1 to this Current Report on Form 8-K.

**Item 9.01 Financial Statements and Exhibits**

(d) Exhibits

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| | |
|:---|:---|
| **Exhibit**<br>**Number** | **Description of Exhibit** |
| 99.1 | [<u>Press release, dated January 6, 2026.</u>](atos-ex99_1.htm) |
| 104 | Cover Page Interactive Data File (embedded within the Inline XBRL document). |

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**SIGNATURES**

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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| | | | |
|:---|:---|:---|:---|
|  |  |  | <br>Atossa Therapeutics, Inc.  |
| Date: | January 6, 2026 | By:  | /s/ Mark J. Daniel |
|  |  |  | Mark J. Daniel<br>*Chief Financial Officer*<br>*(Principal Financial and Accounting Officer)* |

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## Exhibit 99.1

**Exhibit 99.1**

![img248274862_0.jpg](img248274862_0.jpg)

**Atossa Therapeutics Receives FDA "Study May Proceed" Letter for (Z)-Endoxifen Investigational New Drug Application for Metastatic Breast Cancer**

SEATTLE, WA, January 6, 2026 (GLOBE NEWSWIRE) — Atossa Therapeutics, Inc. (Nasdaq: ATOS), a clinical-stage biopharmaceutical company developing innovative medicines for unmet medical needs, today announced that the U.S. Food and Drug Administration ("FDA") issued a "Study May Proceed" letter for the Company's study in metastatic breast cancer which was the subject of a recent investigational new drug application for (Z)-endoxifen.

"This letter marks an important regulatory milestone for Atossa and to potentially expand the use of (Z)-endoxifen for metastatic ER+/HER2- Breast Cancer. We believe its activity, even in tumors that have developed resistance to other endocrine therapies and in the oncogenic signaling pathway, protein kinase C beta 1 (PKCβ1), may offer a new tool in treating this disease.," said Dr. Steven Quay, M.D., Ph.D., Atossa Therapeutics President and Chief Executive Officer. "We appreciate the FDA's review and look forward to advancing this clinical investigation."

**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 U.S. patents and numerous pending applications worldwide.

**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.

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**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 the timing thereof, 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.

**Investor and Media Contact<br>Core IR<br>ir@atossatherapeutics.com** 

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