Atossa Therapeutics Announces Acceptance of Four Abstracts Highlighting (Z)-Endoxifen Research for Presentation at the 2025 San Antonio Breast Cancer Symposium

Studies highlight findings in the use of (Z)-endoxifen to advance breast cancer treatment and prevention

SEATTLE,Nov. 6, 2025/PRNewswire/ -- Atossa Therapeutics, Inc. (Nasdaq:ATOS) ("Atossa" or the "Company"), a clinical-stage biopharmaceutical company developing innovative medicines in oncology, announces that four abstracts featuring data on (Z)-endoxifen have been accepted for presentation at the San Antonio Breast Cancer Symposium (SABCS), being held on December 9-12, 2025, in San Antonio, TX.

"We continue to add to our body of clinical evidence. At SABCS 2025, we look forward to four poster presentations highlighting findings from studies evaluating the use of (Z)-endoxifen to advance breast cancer treatment and prevention," said Dr. Steven Quay, Atossa Therapeutics President and Chief Executive Officer.

About Atossa Therapeutics

Atossa Therapeutics, Inc. (Nasdaq:ATOS) is a clinical-stage biopharmaceutical company developing innovative therapies for significant unmet needs in breast cancer. Atossa's strategy emphasizes disciplined capital allocation, focusing resources on programs and data packages that can enable future regulatory submissions and potential commercialization. For more information, visitwww.atossatherapeutics.comand refer to Atossa's filings with the U.S. Securities and Exchange Commission (SEC).

Forward-Looking StatementsThis press release contains forward-looking statements, including statements regarding Atossa's commercial readiness, financing strategy, operational plans, and the development and potential commercialization of (Z)-endoxifen. These statements are subject to risks and uncertainties that could cause actual results to differ materially, including market conditions, regulatory outcomes, clinical results, manufacturing and supply, intellectual-property challenges, and the Company's ability to secure sufficient funding on acceptable terms. For a discussion of risks and uncertainties, please refer to Atossa's filings with the U.S. Securities and Exchange Commission. Atossa undertakes no obligation to update forward-looking statements, except as required by law.