Atossa Therapeutics, Inc.

Atossa Therapeutics Announces Publication of Novel (Z)-Endoxifen-Related Compounds Demonstrating Potent Anti-Cancer Activity in ER-Positive Breast Cancer

2026-07-28 08:30:00

Peer-reviewed preclinical study published in npj Breast Cancer identifies new chemical entities with activity in ESR1-mutant models Findings suggest potential for combination with abemaciclib SEATTLE, July 28, 2026 /PRNewswire/ -- Atossa Therapeutics, Inc. (NASDAQ: ATOS) ("Atossa" or the "Company"), a clinical-stage biopharmaceutical company developing novel therapies in oncology and other areas of significant unmet clinical need, today announced the publication of a peer-reviewed preclinical study in npj Breast Cancer evaluating five novel chemical entities structurally related to (Z)-endoxifen. The study titled, "Novel (Z)-endoxifen-related new chemical entities exhibit potent anti-cancer activity in ERα+ breast cancer," reported anti-estrogenic and anti-cancer activity across multiple estrogen receptor-positive breast cancer models, including models harboring clinically relevant activating mutations in ESR1.

Atossa Therapeutics Announces Presentation of Mechanism-Driven (Z)-Endoxifen Data in McCune-Albright Syndrome at AACR Special Conference on Rare Cancers

2026-07-21 08:30:00

Preclinical Data Poster Highlights Dual Estrogen Receptor and PKC-β/AKT Pathway Modulation as a Potential Therapeutic Strategy for Estrogen-Driven Pathology in McCune-Albright syndrome SEATTLE, July 21, 2026 /PRNewswire/ -- Atossa Therapeutics, Inc. (NASDAQ: ATOS) ("Atossa" or the "Company"), a clinical-stage biopharmaceutical company developing novel therapies in oncology and other areas of significant unmet clinical need, today announced that a poster presentation titled "Dual estrogen receptor and PKC-β signaling modulation by (Z)-Endoxifen: A mechanism-driven therapeutic strategy for estrogen-driven pathology in McCune-Albright Syndrome" was presented at the AACR Special Conference in Cancer Research: Breaking Barriers in the Fight Against Rare Cancers, which took place July 18-20, 2026, in Vancouver, BC, Canada. Presentation Details Session Type: Poster Session A Date: Saturday, July 18, 2026, 7:30-9:30 pm PT Abstract Number: A010  Location: AACR Special Conference in Cancer Research: Breaking Barriers in the Fight Against Rare Cancers, Vancouver, BC, Canada Poster Title: Dual estrogen receptor and PKC-β signaling modulation by (Z)-Endoxifen: A mechanism-driven therapeutic strategy for estrogen-driven pathology in McCune-Albright Syndrome  Presenter: Sandra Hammer, PhD, Atossa Therapeutics Inc. Summary: The poster supports a dual mechanism of action for (Z)-endoxifen in estrogen-driven pathology relevant to McCune Albright Syndrome-associated Peripheral Precocious Puberty (MAS-PPP): the blockade of ER-mediated transcription downstream of autonomous estrogen production and suppression of PKC-β/AKT-associated proliferative and cell-cycle signaling.

Atossa Therapeutics Announces Closing of Registered Direct Offering of up to $16.5 Million in Gross Proceeds

2026-06-12 17:30:00

$4.5 million upfront with up to an additional $12 million of potential aggregate gross proceeds upon exercise in full of warrants SEATTLE, June 12, 2026 /PRNewswire/ -- Atossa Therapeutics, Inc. (Nasdaq: ATOS) ("Atossa" or the "Company"), a clinical-stage biopharmaceutical company developing novel therapies in oncology and other areas of high unmet clinical need, today announced the closing of its previously announced registered direct offering of 1,363,637 shares (the "Shares") of its common stock, par value $0.18 per share ("Common Stock") (or common stock equivalents in lieu thereof), Series A warrants to purchase up to 1,363,637 shares of Common Stock and short-term Series B warrants to purchase up to 1,363,637 shares of Common Stock (such warrants, collectively, the "Series Warrants") and accompanying Series Warrants. The Series Warrants are exercisable six months following the date of issuance.

Atossa Therapeutics Announces Registered Direct Offering of up to $16.5 Million in Gross Proceeds

2026-06-11 08:00:00

$4.5 million upfront with up to an additional $12 million of potential aggregate gross proceeds upon exercise in full of warrants SEATTLE, June 11, 2026 /PRNewswire/ -- Atossa Therapeutics, Inc. (Nasdaq: ATOS) ("Atossa" or the "Company"), a clinical-stage biopharmaceutical company developing novel therapies in oncology and other areas of high unmet clinical need, today announced that it has entered into a securities purchase agreement with institutional investors for the purchase and sale of 1,363,638 shares (the "Shares") of its common stock, par value $0.18 per share ("Common Stock") (or common stock equivalents in lieu thereof), Series A warrants to purchase up to 1,363,638 shares of Common Stock and short-term Series B warrants to purchase up to 1,363,638 shares of Common Stock (such warrants, collectively, the "Series Warrants") and accompanying Series Warrants in a registered direct offering. The Series Warrants will be exercisable six months following the date of issuance.

Atossa Therapeutics Announces ASCO 2026 Abstracts Highlighting (Z)-Endoxifen Activity Across ESR1 Mutations and Ongoing EVANGELINE Phase 2 Trial

2026-05-27 08:30:00

Preclinical Data Abstract Demonstrates Robust Estrogen Receptor (ER) Inhibition in ESR1-Mutant Breast Cancer Models at Clinically Relevant Concentrations Trial-in-Progress Abstract Details Ongoing Phase 2 EVANGELINE Study of (Z)-Endoxifen Plus Goserelin as Neoadjuvant Therapy in Premenopausal Women With ER+/HER2- Breast Cancer SEATTLE, May 27, 2026 /PRNewswire/ -- Atossa Therapeutics, Inc. (Nasdaq: ATOS) ("Atossa" or the "Company"), a clinical-stage biopharmaceutical company developing novel therapies in oncology and other areas of significant unmet medical need, today announced that two abstracts featuring (Z)-endoxifen have been accepted for presentation at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting, being held May 29 to June 2, 2026 in Chicago, IL. "Both abstracts highlight the scientific rationale and ongoing clinical development of (Z)-endoxifen in ER-positive breast cancer," said Dr. Steven C.

Atossa Therapeutics Announces Acceptance of Manuscript Highlighting Utrophin-Modulation Potential of (Z)-Endoxifen in Duchenne Muscular Dystrophy

2026-05-20 16:45:00

Review article accepted for publication in Degenerative Neurological and Neuromuscular Disease and builds on Atossa's previously published Duchenne Muscular Dystrophy (DMD) research SEATTLE, May 20, 2026 /PRNewswire/ -- Atossa Therapeutics, Inc. (NASDAQ: ATOS) (Atossa or the Company), a clinical-stage biopharmaceutical company developing novel therapies in oncology and other areas of significant unmet clinical need, today announced that the manuscript titled, "(Z)-Endoxifen as a Potential Modulator of Utrophin Pathways in Duchenne Muscular Dystrophy: A Mechanistic and Transcriptomic Perspective," has been accepted for publication in Degenerative Neurological and Neuromuscular Disease. The review centers on utrophin, a structural and functional homolog of dystrophin.

Atossa Therapeutics, Inc. (ATOS) Discusses Challenges in Breast Cancer Drug Development and Innovation in Clinical Research Transcript

2026-05-19 23:50:58

Atossa Therapeutics, Inc. (ATOS) Discusses Challenges in Breast Cancer Drug Development and Innovation in Clinical Research Transcript

Atossa Therapeutics to Host Virtual KOL Event Featuring Dr. Laura Esserman to Discuss Development of (Z)-Endoxifen in ER-Positive Breast Cancer

2026-05-14 08:30:00

Event to feature Dr. Laura Esserman, internationally recognized surgical oncologist, breast cancer expert, and founder and principal investigator of the I-SPY Trials SEATTLE, May 14, 2026 /PRNewswire/ -- Atossa Therapeutics, Inc. (Nasdaq: ATOS) ("Atossa" or the "Company"), a clinical-stage biopharmaceutical company developing novel therapies in oncology and other areas of significant unmet medical need, today announced that it will host a virtual key opinion leader event focused on the evolving clinical and translational data supporting the development of (Z)-endoxifen, the Company's investigational selective estrogen receptor modulator/degrader, or SERM/D, as a potential next-generation endocrine therapy backbone across multiple estrogen receptor ("ER") -positive breast cancer settings. The event will feature internationally recognized surgical oncologist and breast cancer expert Dr. Laura Esserman.