Atossa Therapeutics (NASDAQ: ATOS) settles key Endoxifen patent fight

Rhea-AI Filing Summary

Atossa Therapeutics, Inc. entered into a Settlement Agreement with Intas Pharmaceuticals Ltd. and Jina Pharmaceuticals, Inc. to resolve patent disputes over Endoxifen-related intellectual property, including pending challenges before the U.S. Patent and Trademark Office’s Patent Trial and Appeal Board.

The parties agreed to seek termination of the identified PTAB proceedings and, if any proceeding is not fully terminated, not to participate further in that proceeding or related appeals, subject to the agreement’s terms. They also exchanged mutual covenants not to challenge specified Endoxifen-related patents and applications, with limited exceptions.

The agreement preserves Atossa’s ability to continue developing and commercializing Z-endoxifen base in its principal focus areas of oncology, endocrine dysfunction disorders and muscular dystrophy-related diseases, and allocates certain other Endoxifen-related fields and formulations among the parties. Atossa expects its two issued “Methods for Making and Using Endoxifen” U.S. patents to remain issued and fully enforceable against other third parties, and believes the settlement reduces uncertainty around its patent portfolio and supports its strategic development plans.

Positive

• Core IP disputes resolved: Atossa settled Endoxifen-related patent challenges with Intas and Jina, expects its two “Methods for Making and Using Endoxifen” U.S. patents to remain issued and fully enforceable, and believes the agreement reduces uncertainty around its patent portfolio while supporting strategic development of Z-endoxifen base.

Negative

• None.

Insights

Biotech IP and regulatory specialist

Settlement removes key PTAB challenges to Atossa’s core Endoxifen patents.

Atossa Therapeutics has resolved Endoxifen-related patent disputes with Intas and Jina through a Settlement Agreement that covers pending Patent Trial and Appeal Board proceedings. The parties will seek termination of those proceedings and, if not fully terminated, have committed not to participate further, limiting ongoing challenges.

The agreement includes mutual covenants not to challenge specified Endoxifen-related patents and applications, while preserving Atossa’s ability to develop and commercialize Z-endoxifen base in oncology, endocrine dysfunction disorders and muscular dystrophy-related diseases. This supports continuity for the company’s core development programs.

Atossa expects its two U.S. patents titled “Methods for Making and Using Endoxifen” to remain issued and fully enforceable against other third parties. Future company filings may clarify how this IP stability interacts with clinical progress, regulatory milestones and capital needs described in existing risk disclosures.

8-K Event Classification

Item 8.01 — Other Events

1 item

Item 8.01 Other Events Other

Voluntary disclosure of events the company deems important to shareholders but not covered by other items.

Key Terms

Settlement Agreement, Patent Trial and Appeal Board, Endoxifen-related intellectual property, forward-looking statements, +1 more

5 terms

Settlement Agreement financial

"the Company entered into a Settlement Agreement (the “Settlement Agreement”) with Intas Pharmaceuticals Ltd."

A settlement agreement is a legally binding deal where two sides resolve a dispute—often a lawsuit—by agreeing on terms such as payments, actions, or changes in behavior instead of continuing the case to trial. For investors it matters because settlements can create immediate costs, limit future liabilities or risks, and change a company's cash flow, reputation, or ongoing obligations much like paying a negotiated bill to avoid a lengthy, uncertain fight.

Patent Trial and Appeal Board regulatory

"including pending proceedings before the U.S. Patent and Trademark Office Patent Trial and Appeal Board"

The Patent Trial and Appeal Board is an administrative body that reviews and decides challenges to the validity of issued patents and hears appeals of patent office decisions. For investors, its rulings can make or break a company’s exclusive rights to a product or technology—similar to a referee overturning a game-winning call—affecting future revenue, legal costs, and the value of related securities.

Endoxifen-related intellectual property financial

"resolve patent disputes related to Endoxifen-related intellectual property, including pending proceedings"

forward-looking statements regulatory

"contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995"

Forward-looking statements are predictions or plans that companies share about what they expect to happen in the future, like estimating sales or profits. They matter because they help investors understand a company's outlook, but since they are based on guesses and assumptions, they can sometimes be wrong.

Z-endoxifen base financial

"developing and commercializing Z-endoxifen base in the Company’s principal areas of focus"

Understanding 8-K Material Events →

NASDAQ false 0001488039 0001488039 2026-04-13 2026-04-13

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): April 13, 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 the 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 April 16, 2026, Atossa Therapeutics, Inc. (the “Company”) announced that on April 13, 2026, the Company entered into a Settlement Agreement (the “Settlement Agreement”) with Intas Pharmaceuticals Ltd. (“Intas”) and Jina Pharmaceuticals, Inc., which is intended to resolve patent disputes related to Endoxifen-related intellectual property, including pending proceedings before the U.S. Patent and Trademark Office Patent Trial and Appeal Board (“PTAB”).

As previously disclosed by the Company, the PTAB proceedings include challenges brought by Intas against two patents owned by the Company. Pursuant to the Settlement Agreement, the parties have agreed to seek termination of the PTAB proceedings identified in the Settlement Agreement. In the event any such proceeding is not terminated in its entirety, the applicable parties have agreed not to participate further in such proceeding, or in any related appeal, in each case subject to and in accordance with the terms of the Settlement Agreement.

The Settlement Agreement also includes mutual covenants pursuant to which the parties have agreed not to challenge, directly or indirectly, specified Endoxifen-related patents and patent applications owned or controlled by the other parties, subject to limited exceptions set forth in the Settlement Agreement.

In addition, the Settlement Agreement preserves the Company’s ability to continue developing and commercializing Z-endoxifen base in the Company’s principal areas of focus of oncology, endocrine dysfunction disorders and muscular dystrophy-related diseases. The Settlement Agreement also establishes agreed allocations between the parties with respect to certain other Endoxifen-related fields and formulations.

Upon anticipated termination by the PTAB of the proceedings, the Company’s two issued patents titled, “Methods for Making and Using Endoxifen” (U.S. Patents Nos. 11,261,151 and 12,071,391), that are subject to such proceedings, are expected to remain issued and fully enforceable against other third parties.

The Company believes the Settlement Agreement helps reduce uncertainty arising from the pending challenges to the Company’s patent portfolio and supports continued execution of the Company’s strategic development plans for Z-endoxifen base in its core therapeutic areas.

Forward-Looking Statements

This Current Report on Form 8-K contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, including without limitation statements regarding the anticipated termination of PTAB proceedings, the expected impact of the Settlement Agreement, the Company’s plans and ability to continue developing Z-endoxifen base in its core therapeutic areas and the expected strategic benefits of resolving the patent disputes. Forward-looking statements are based on current expectations and assumptions and are subject to risks and uncertainties that could cause actual results to differ materially from those expressed or implied by such statements. These risks and uncertainties include, among others, risks relating to the implementation of the Settlement Agreement, any actions by the PTAB with respect to the requested terminations, the Company’s clinical development activities, regulatory developments, capital needs and other risks described from time to time in the Company’s filings with the U.S. Securities and Exchange Commission. The Company undertakes no obligation to update any forward-looking statements except as required by law.

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: April 16, 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 8-K filing?

Atossa Therapeutics announced a Settlement Agreement with Intas Pharmaceuticals and Jina Pharmaceuticals to resolve Endoxifen-related patent disputes, including PTAB challenges, which it believes reduces uncertainty around its patent portfolio and supports continued development of Z-endoxifen base in its main therapeutic areas.

Which patents are affected by Atossa Therapeutics’ Endoxifen settlement?

The settlement covers disputes involving two issued U.S. patents titled “Methods for Making and Using Endoxifen” (U.S. Patents Nos. 11,261,151 and 12,071,391). Atossa expects these patents to remain issued and fully enforceable against other third parties after anticipated termination of the related PTAB proceedings.

How does the Settlement Agreement impact Atossa’s Z-endoxifen development plans?

The Settlement Agreement preserves Atossa’s ability to continue developing and commercializing Z-endoxifen base in oncology, endocrine dysfunction disorders and muscular dystrophy-related diseases. The company believes resolving these patent challenges supports execution of its strategic development plans in those core therapeutic areas.

What happens to the PTAB proceedings under Atossa’s Settlement Agreement?

Under the Settlement Agreement, the parties agreed to seek termination of the identified PTAB proceedings. If any proceeding is not fully terminated, the applicable parties agreed not to participate further in that proceeding or any related appeal, in each case subject to the agreement’s terms.

Do Atossa and the other parties agree not to challenge Endoxifen patents in the future?

Yes. The Settlement Agreement includes mutual covenants where Atossa, Intas and Jina agree not to challenge, directly or indirectly, specified Endoxifen-related patents and patent applications owned or controlled by the others, subject to limited exceptions described in the agreement’s terms.

Does the Atossa settlement change its ability to pursue other Endoxifen opportunities?

The Settlement Agreement establishes agreed allocations between the parties for certain other Endoxifen-related fields and formulations. Atossa states the arrangement preserves its principal focus on oncology, endocrine dysfunction disorders and muscular dystrophy-related diseases while defining how other Endoxifen opportunities are shared.

Filing Exhibits & Attachments

3 documents

Other Documents

• EX-101 XBRL TAXONOMY EXTENSION SCHEMA 3.1 KB
• EX-101 XBRL TAXONOMY EXTENSION LABEL LINKBASE 17.6 KB
• EX-101 XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE 11.0 KB