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. (Nasdaq: ATOS) is a clinical-stage biopharmaceutical company whose news flow centers on the development of its lead investigational therapy, (Z)-Endoxifen. Company announcements frequently cover progress in breast cancer programs, regulatory interactions, intellectual property developments, and emerging opportunities in other serious diseases.
Investors following ATOS news can expect regular updates on clinical trials involving (Z)-Endoxifen, including studies in metastatic ER+/HER2- breast cancer, neoadjuvant treatment for premenopausal ER+/HER2- patients, breast cancer risk reduction strategies focused on mammographic breast density, and participation in the RECAST DCIS platform trial for hormone receptor–positive ductal carcinoma in situ. These releases often summarize trial design, early findings, and the potential implications for future registration strategies.
Atossa’s news also highlights regulatory milestones, such as FDA Type C meetings, Investigational New Drug (IND) submissions, and “Study May Proceed” letters. Additional coverage includes the FDA’s Rare Pediatric Disease designation for (Z)-Endoxifen in Duchenne Muscular Dystrophy, as well as AI-enabled research collaborations identifying new oncology indications like glioblastoma.
Another recurring theme in ATOS news is the company’s intellectual property position, including newly issued patents for enteric oral (Z)-Endoxifen formulations and methods of use in hormone-dependent breast disorders and estrogen-related conditions. Corporate updates, such as financial results, leadership appointments, and Nasdaq listing communications, provide context on Atossa’s operational and strategic direction.
By monitoring this news page, readers can review a chronological record of Atossa’s clinical, regulatory, scientific, and corporate announcements related to (Z)-Endoxifen and the company’s broader oncology and rare disease programs.
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.
Atossa Therapeutics (Nasdaq: ATOS) presented preclinical data on (Z)-endoxifen at the 2026 MDA Clinical & Scientific Conference showing improved muscle strength, reduced damage biomarkers, better body composition, and tolerance in mdx5Cv dystrophic mice.
The company said results support continued clinical development for Duchenne muscular dystrophy.
Atossa Therapeutics (Nasdaq: ATOS) summarized 2025 progress and outlined 2026 priorities for its proprietary oral (Z)-endoxifen. Key developments include FDA Type C feedback (Nov 17, 2025), IND activity and a paused metastatic program, Rare Pediatric and Orphan Drug designations for DMD, new U.S. patent claims, a reverse stock split (effective Feb 2, 2026), and >$40 million cash on hand.
The company is completing I-SPY 2 enrollment, pursuing non-oncology indications (DMD, MAS), defending USPTO patent proceedings with Intas, and prioritizing regulatory interactions and partnership opportunities in 2026.
Atossa Therapeutics (NASDAQ: ATOS) reaffirmed its market position for (Z)-endoxifen in Duchenne muscular dystrophy (DMD) after Congress reauthorized the Rare Pediatric Disease Priority Review Voucher (PRV) program for five years on Feb 5, 2026. The drug holds Rare Pediatric Disease (RPD) designation and would be eligible for a PRV if FDA approval is obtained. PRVs can accelerate future reviews or be sold/transferred; disclosed PRV sales in the last 18 months ranged from $150–$200 million. Atossa cites emerging preclinical data and plans to advance the program toward clinical development for boys with DMD.
Atossa Therapeutics (NASDAQ: ATOS) announced on January 21, 2026 that Founder and CEO Steven Quay, M.D., Ph.D. was named one of The Top 50 Healthcare Technology CEOs of 2025 by The Healthcare Technology Report. The recognition cites his leadership advancing Atossa's lead therapy, (Z)-endoxifen, across multiple Phase 2 trials and its optimization as a SERM/D with added PKCβ1 inhibition to provide consistent systemic exposure independent of CYP2D6 metabolism.
The company is also exploring (Z)-endoxifen for Duchenne Muscular Dystrophy and highlights a people-centered, innovation-driven culture under Dr. Quay.
Atossa Therapeutics (NASDAQ: ATOS) announced that the U.S. Food and Drug Administration Office of Orphan Products Development has granted Orphan Drug Designation to (Z)-endoxifen for the treatment of Duchenne muscular dystrophy (DMD) on January 16, 2026. This designation follows a previously received Rare Pediatric Disease designation and supports continued development of (Z)-endoxifen in this rare pediatric neuromuscular disorder. The company said it will continue engaging with the FDA as it advances development efforts and will provide updates as appropriate.
Atossa Therapeutics (Nasdaq: ATOS) announced on January 6, 2026 that the U.S. Food and Drug Administration issued a "Study May Proceed" letter for its investigational new drug application for (Z)-endoxifen in metastatic ER+/HER2- breast cancer.
The company presented this as a regulatory milestone to advance a clinical study testing (Z)-endoxifen's activity, including in tumors with resistance to other endocrine therapies and targeting the oncogenic signaling pathway PKCβ1. No clinical efficacy or safety results were reported in this announcement.
Atossa Therapeutics (Nasdaq: ATOS) was named a winner of the 2025 Clinical Trials Arena Research and Development Excellence Award in the Precision Endocrine Therapy category on December 17, 2025.
The company was honored for advancing (Z)-endoxifen, a precision-engineered SERM/D with PKCβ1 inhibition intended to provide consistent systemic exposure independent of CYP2D6 metabolism. (Z)-endoxifen is being evaluated across metastatic, neoadjuvant, adjuvant, and risk-reduction breast cancer settings, with an emerging application in Duchenne muscular dystrophy. The award recognizes scientific rigor and innovation in clinical research and development.
Atossa Therapeutics (Nasdaq: ATOS) presented four clinical updates at SABCS 2025 on (Z)-endoxifen, covering DCIS active surveillance, low-dose I-SPY2 pilot data, ESR1-mutant mechanistic results, and the Phase 2 EVANGELINE neoadjuvant trial.
Key facts: daily 10 mg (Z)-endoxifen was well tolerated with 95% of patients completing ≥75% therapy; MRI tumor volume median change was -72%; ctDNA clearance occurred in 70% of initially positive patients; EVANGELINE run-in showed 86% with Week 4 Ki-67 ≤10% supporting a 40 mg Phase 2 dose.