Atossa Therapeutics

ATOS

Market cap $45M

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.

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

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.

SEATTLE, May 8, 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 announces its financial results and provides an update on recent corporate developments for the first quarter ended March 31, 2026. "During the quarter, we made meaningful progress advancing our (Z)-endoxifen development strategy across both oncology and rare disease indications," stated Dr. Steven Quay, M.D.

Peer-reviewed data support (Z)-endoxifen's (Endoxifen) potential as a differentiated breast cancer risk prevention candidate by marked reduction of mammographic breast density (MBD) Doses of both 1 mg and 2 mg daily Endoxifen significantly reduced MBD versus placebo after six months 1 mg dose achieved clinically meaningful density reduction with a tolerability profile similar to placebo, supporting further development in women at elevated breast cancer risk SEATTLE, May 6, 2026 /PRNewswire/ -- Atossa Therapeutics, Inc. (Atossa or the Company) (Nasdaq: ATOS), a clinical-stage biopharmaceutical company focused on developing novel therapies targeting breast cancer and rare diseases, today announced the publication of results from the KARISMA Endoxifen trial in the Journal of the National Cancer Institute (JNCI). The randomized, double-blind, placebo-controlled Phase 2 study evaluated daily oral Endoxifen and demonstrated that low-dose Endoxifen significantly reduced MBD, a key risk factor for breast cancer.

Designation expands (Z)-endoxifen program into rare pediatric endocrine disorder and qualifies Atossa for a Priority Review Voucher award upon approval SEATTLE, May 4, 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 the U.S. Food and Drug Administration ("FDA") has granted Rare Pediatric Disease ("RPD") designation to (Z)-endoxifen for the treatment of McCune-Albright Syndrome ("MAS") in females. RPD designation is granted to drug candidates intended to treat serious or life-threatening diseases that primarily affect individuals from birth to 18 years of age.

SEATTLE, March 25, 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 announces its financial results for the fourth quarter and year ended December 31, 2025 and provides an update on recent corporate developments. "While we have consistently made meaningful and measurable progress across our (Z)-endoxifen development strategy in oncology over the last 12 months, we continue to explore the best opportunities to leverage the technology where it may help to address serious health conditions and unmet medical needs.

Kathy Puyana Theall, M.D. and Adebola Giwa, M.D.

Study Highlights Findings that (Z)-endoxifen Restores Muscle Performance and Lowers Damage Biomarkers in mdx5Cv Dystrophic Mice SEATTLE, March 12, 2026 /PRNewswire/ -- Atossa Therapeutics, Inc. (Nasdaq: ATOS) ("Atossa" or the "Company"), a clinical-stage biopharmaceutical company developing novel therapies in oncology and other rare disease indications with significant unmet need, presented an oral clinical trial update on (Z)-endoxifen at the MDA Clinical & Scientific Conference on March 11, 2026, in Orlando, FL. Presentation Highlights The mdx5Cv Dystrophic mouse model, a trusted, reproducible standard for Duchenne muscular dystrophy (DMD) preclinical research, was used for this study (Z)-Endoxifen improved muscle strength and motor performance in both juvenile and adult dystrophic mice Treatment enhanced resistance to contraction-induced muscle injury Favorable changes were observed in body composition, including increased lean mass and reduced fat mass Key biochemical and histologic markers of muscle damage were reduced The therapy was well tolerated with no adverse findings observed during the study Clinical Significance DMD is a progressive and ultimately fatal neuromuscular disorder characterized by ongoing muscle degeneration, inflammation, and fibrosis.