FDA clears Atossa (NASDAQ: ATOS) metastatic breast cancer study to proceed

Rhea-AI Filing Summary

Atossa Therapeutics, Inc. reported that on January 6, 2026 the U.S. Food and Drug Administration issued a “Study May Proceed” letter for the company’s study of metastatic breast cancer. This type of letter indicates the FDA has reviewed the planned clinical study and is allowing it to go forward under its current design.

The company disclosed this development through a press release, which is attached as an exhibit to the report. The update highlights progress in Atossa’s efforts to clinically evaluate its approach in patients with metastatic breast cancer, an advanced stage of the disease where new treatment options are often needed.

Positive

• FDA allows metastatic breast cancer study to proceed, marking a key regulatory milestone that moves Atossa’s program from planning into clinical testing.

Negative

• None.

Insights

Biotech and FDA regulatory specialist

FDA’s “Study May Proceed” letter lets Atossa begin a metastatic breast cancer study.

The report states that on January 6, 2026, the U.S. Food and Drug Administration issued a “Study May Proceed” letter for Atossa Therapeutics, Inc. covering its study of metastatic breast cancer. In FDA practice, this phrase means the agency has reviewed the company’s clinical study submission and is permitting the trial to proceed as proposed.

This step is important in oncology because it moves a program from planning into clinical testing in patients with metastatic breast cancer, a serious, late-stage condition. While the report does not provide details on the study’s design or potential timelines, the inclusion of a dedicated press release as Exhibit 99.1 underlines the company’s view that this regulatory milestone is significant for its development pipeline.

false000148803900014880392026-01-062026-01-06

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

FORM 8-K

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

Atossa Therapeutics, Inc.

(Exact name of Registrant as Specified in Its Charter)

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

Registrant’s Telephone Number, Including Area Code: (206) 588-0256

N/A

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

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:

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Common Stock, $0.18 par value		ATOS		The Nasdaq Capital Market

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 ☐

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. ☐

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

Exhibit Number		Description of Exhibit
99.1		Press release, dated January 6, 2026.
104		Cover Page Interactive Data File (embedded within the Inline XBRL document).

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.

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

FAQ

What did Atossa Therapeutics (ATOS) announce in this report?

Atossa Therapeutics announced that on January 6, 2026 the U.S. Food and Drug Administration issued a “Study May Proceed” letter for the company’s study of metastatic breast cancer.

What does the FDA “Study May Proceed” letter mean for Atossa Therapeutics?

The “Study May Proceed” letter indicates the FDA has reviewed Atossa Therapeutics’ planned clinical study of metastatic breast cancer and is allowing the trial to move forward under its proposed design.

Which disease area is involved in Atossa Therapeutics’ new FDA-cleared study?

The FDA clearance applies to Atossa Therapeutics’ planned clinical study in metastatic breast cancer, an advanced stage of breast cancer.

How did Atossa Therapeutics disclose the FDA decision on its metastatic breast cancer study?

Atossa Therapeutics disclosed the FDA decision through a press release dated January 6, 2026, which is attached as Exhibit 99.1 to the report.

Is this Atossa Therapeutics filing mainly financial or clinical in nature?

This filing is clinical in nature, highlighting that the FDA has allowed Atossa Therapeutics’ metastatic breast cancer study to proceed, rather than reporting financial results.

Where can investors find more detail on Atossa Therapeutics’ FDA update?

More detail is contained in the company’s press release filed as Exhibit 99.1, which discusses the FDA’s “Study May Proceed” letter related to the metastatic breast cancer study.