Welcome to our dedicated page for Atossa Therapeutics news (Ticker: ATOS), a resource for investors and traders seeking the latest updates and insights on Atossa Therapeutics stock.
Atossa Therapeutics, Inc. develops clinical-stage medicines for oncology and other areas of unmet medical need. Its recurring news centers on (Z)-endoxifen, the company's lead product candidate, including breast cancer research, mammographic breast density data, and expansion into rare disease indications such as Duchenne muscular dystrophy and McCune-Albright Syndrome.
Company updates also cover FDA orphan and rare pediatric disease designations, clinical and preclinical data presentations, peer-reviewed publications, intellectual property developments, leadership additions, financial results, and capital-allocation commentary tied to Atossa's development strategy.
Atossa Therapeutics (Nasdaq: ATOS) closed a registered direct offering of 1,363,637 common shares (or equivalents) plus Series A and short-term Series B warrants, raising about $4.5 million in gross proceeds.
The Series Warrants could add up to $12 million if fully exercised. Atossa plans to use net proceeds for clinical development, working capital and general corporate purposes.
Atossa Therapeutics (Nasdaq: ATOS) entered a securities purchase agreement for a registered direct offering of 1,363,638 common shares (or equivalents) plus Series A and short-term Series B warrants.
The deal is expected to raise about $4.5 million upfront, with up to $12 million in additional gross proceeds if all warrants are exercised. Proceeds are intended for clinical development, working capital and general corporate purposes.
Atossa Therapeutics (Nasdaq: ATOS) reported two (Z)-endoxifen abstracts accepted for ASCO 2026. Preclinical data show robust estrogen receptor inhibition across key ESR1 mutations, while the ongoing Phase 2 EVANGELINE trial evaluates 40 mg daily (Z)-endoxifen plus goserelin as neoadjuvant therapy in premenopausal ER+/HER2- breast cancer.
Atossa Therapeutics (NASDAQ: ATOS)/b) announced acceptance of a review manuscript in on (Z)-endoxifen as a potential modulator of utrophin pathways in Duchenne muscular dystrophy (DMD).
The article outlines how (Z)-endoxifen may favor utrophin expression and function and proposes preclinical studies and biomarker development as next steps.
Atossa Therapeutics (Nasdaq: ATOS) will host a virtual key opinion leader event on May 19, 2026, highlighting development of its investigational SERM/D (Z)-endoxifen in ER-positive breast cancer.
The webinar will feature breast cancer expert Dr. Laura Esserman discussing emerging clinical and translational data, combination strategies, and development opportunities.
Atossa Therapeutics (Nasdaq: ATOS) reported Q1 2026 results and corporate updates for the quarter ended March 31, 2026. Key developments include FDA Orphan Drug and Rare Pediatric Disease designations for (Z)-endoxifen in DMD and RPD designation for McCune-Albright Syndrome, new preclinical DMD data, senior clinical hires, and a Q1 operating expense increase to $9.9 million.
R&D expenses rose to $4.8M (+15%), G&A to $5.1M (+56%), and interest income fell by $0.4M.
Atossa Therapeutics (Nasdaq: ATOS) announced publication of the KARISMA Endoxifen Phase 2 trial in JNCI showing that daily low-dose Endoxifen significantly reduced mammographic breast density (MBD) in healthy premenopausal women.
Both 1 mg and 2 mg doses reduced MBD versus placebo (1 mg: −19.3%, p=0.004; 2 mg: −26.5%, p<0.001) after six months, with a tolerability profile similar to placebo for 1 mg and no clinically significant lab or vital-sign changes reported.
Atossa Therapeutics (Nasdaq: ATOS) announced that the U.S. FDA granted Rare Pediatric Disease (RPD) designation to (Z)-endoxifen for treatment of McCune-Albright Syndrome (MAS) in females on May 4, 2026. RPD status may make the program eligible for a Priority Review Voucher (PRV) upon approval; disclosed PRV sales in the last 18–24 months ranged from approximately $100–$205 million. The company cited scientific rationale for (Z)-endoxifen as a potent SERM/D and noted engagement with the FD/MAS clinical and patient community while it defines a clinical development path for MAS.
Atossa Therapeutics (NASDAQ: ATOS) reported 2025 year-end results and corporate updates on March 25, 2026. Key regulatory milestones include FDA Rare Pediatric Disease designation (Dec 2025) and Orphan Drug designation (Jan 2026) for (Z)-endoxifen in Duchenne Muscular Dystrophy. Total operating expenses were $37.1 million in 2025 versus $27.6 million in 2024, driven by higher R&D and G&A costs.
The company highlighted peer-reviewed publication, clinical award recognition, new clinical hires, and increased clinical trial spending to advance (Z)-endoxifen across oncology and rare-disease programs.
Atossa Therapeutics (Nasdaq: ATOS) on March 19, 2026 added two senior clinical leaders: Kathy Puyana Theall, M.D. as Medical Director - Breast Oncology and Adebola Giwa, M.D. as Medical Director - Rare Diseases.
These hires bolster development of (Z)-Endoxifen across breast cancer and rare disease programs, including McCune-Albright syndrome and Duchenne muscular dystrophy, and bring regulatory and global trial experience to support upcoming clinical and regulatory milestones.