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), a clinical-stage biopharmaceutical company focused on breast cancer treatment and prevention, announced that CEO Dr. Steven Quay will participate in a fireside chat at the H.C. Wainwright 27th Annual Global Investment Conference on September 8, 2025.
During the presentation, Dr. Quay will discuss updates on the company's lead program (Z)-endoxifen, a Selective Estrogen Receptor Modulator (SERM) designed for breast cancer prevention and treatment. The discussion will cover multiple clinical studies progress and recent encouraging regulatory feedback that could accelerate development.
The presentation will be available via webcast with a 90-day replay period on Atossa's investor website. A preview video message from Dr. Quay is currently available.
Atossa Therapeutics (NASDAQ: ATOS) has selected PSI as its Contract Research Organization (CRO) for a pivotal Phase 2 dose-ranging study of (Z)-endoxifen in metastatic breast cancer. The study, designed with FDA guidance, will evaluate the drug's safety, pharmacokinetics/pharmacodynamics, and preliminary anti-tumor activity.
The company plans to file an Investigational New Drug (IND) application in Q4 2025, with patient enrollment following thereafter and topline data expected in 2026. The study aims to inform a subsequent Phase 3 trial. The market opportunity includes approximately 170,000 women living with metastatic breast cancer in the United States.
PSI, selected for its expertise in oncology trials, achieved a 93% on-time or ahead-of-schedule enrollment rate in 2024. Atossa is also advancing additional Phase 2 studies of (Z)-endoxifen in various breast cancer settings, with multiple clinical readouts expected in the coming months.
Atossa Therapeutics (NASDAQ:ATOS) reported significant progress in Q2 2025, highlighted by positive FDA feedback for its (Z)-endoxifen breast cancer treatment program. The FDA cleared the path for IND filing in Q4 2025, confirming no additional toxicity studies are required.
The company's I-SPY2 trial showed strong results, with 95% of subjects completing planned dosing and median Ki-67 dropping from 10.5% to 5% by Week 3. Tumor volume decreased by 77.7% from baseline to surgery. Financial results showed R&D expenses increased 55% to $5.5 million in Q2 2025, while G&A expenses remained stable at $3.5 million.
Atossa strengthened its patent portfolio with new U.S. Patent No. 12,281,056, although two patents face challenges. The company maintains a strong cash position and has deliberately avoided using its ATM facility at current share price levels.
Atossa Therapeutics (NASDAQ: ATOS) received positive FDA feedback regarding their proposed dose optimization trial of (Z)-endoxifen for treating ER+/HER2- metastatic breast cancer. The FDA's written responses affirmed key elements of Atossa's clinical development plan, eliminating the need for a pre-IND meeting.
Key developments include: FDA approval of the dose optimization strategy, support for combination studies with standard-of-care therapies, confirmation of adequate nonclinical data package, and agreement on cardiac safety assessments. The company plans to submit an IND in Q4 2025 and will soon announce specific details about the target patient population and trial design.
The development aligns with FDA's Project Optimus initiative, which emphasizes data-driven dose exploration to maximize benefits while minimizing toxicity.
Atossa Therapeutics (NASDAQ:ATOS) will host a live investor webinar and Q&A session on May 22, 2025, at 4:15 p.m. ET. The event, hosted by RedChip Companies, will feature CEO Dr. Steven Quay discussing the company's lead clinical candidate, (Z)-endoxifen, a next-generation SERM targeting metastatic breast cancer. The presentation will cover multiple ongoing Phase 2 studies showing strong clinical activity, improved tolerability, and favorable safety profiles. Investors will learn about recent progress, upcoming milestones, and how Atossa's differentiated science and capital-efficient model aim to create clinical impact and shareholder value.
Atossa Therapeutics (NASDAQ: ATOS) has reported full results from its Phase 2 Endocrine Optimization Pilot sub-study within the I-SPY 2 TRIAL, evaluating low-dose oral (Z)-endoxifen for treating stage II/III ER+, HER2-negative breast cancer. The study achieved its primary feasibility goal with 95% of participants completing at least 75% of planned dosing. Key findings showed median Ki-67 reduction from 10.5% to 5% by Week 3, and median functional tumor volume decreased 77.7%. The treatment demonstrated a favorable safety profile with mostly Grade 1 adverse events.
However, no participants achieved pathologic complete response (pCR), with residual cancer burden classes showing moderate to extensive residual disease. This was expected due to the intentionally low 10mg dose. Atossa is now enrolling participants for additional I-SPY 2 cohorts testing higher doses (40mg) of (Z)-endoxifen, both alone and combined with abemaciclib, with top-line data expected in 2026.
Atossa Therapeutics (Nasdaq: ATOS) has secured a significant patent victory with the issuance of U.S. Patent No. 12,281,056 by the USPTO. The patent includes 58 claims covering (Z)-endoxifen formulations and therapeutic methods for their use.
The new patent specifically protects highly pure and stable enteric oral formulations of (Z)-endoxifen, a potent Selective Estrogen Receptor Modulator (SERM). This development strengthens Atossa's intellectual property portfolio in breast cancer treatment innovation.
Led by CEO Steven Quay, M.D., Ph.D., the company continues to expand its patent estate, which now includes multiple U.S. patents with over 200 patent claims related to (Z)-endoxifen formulations and clinical applications. This strategic protection reinforces Atossa's position in developing targeted therapies for hormone receptor-positive breast cancer.
Atossa Therapeutics has proposed a groundbreaking Phase 3 clinical study called SMART 2.0 at the AACR 2025 Annual Meeting. The study aims to investigate (Z)-endoxifen, a Selective Estrogen Receptor Modulator (SERM), for reducing interval breast cancer in high-risk women.
Key highlights:
- The study targets interval breast cancers, which occur between regular mammography screenings and are typically more aggressive
- Low-dose (1mg) Z-endoxifen reduced mammographic density by nearly 20% at six months in Phase 2 KARISMA trial
- Side effects were not statistically different from placebo
- The proposed trial will use AI Risk modeling to identify and randomize participants
- Primary endpoint: measuring reduction in interval breast cancer incidence over two years
This research represents a potential advancement in breast cancer prevention, offering a safer alternative to existing treatments like tamoxifen.
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