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) has requested a Type C meeting with the FDA to discuss accelerating the development of low-dose (Z)-endoxifen for breast cancer risk reduction. The company expects to update shareholders on the meeting outcome by year-end 2025.
The potential market includes 1.6-2.1 million annual tamoxifen prescriptions in the U.S. across three settings: adjuvant therapy, DCIS risk reduction, and high-risk women without prior cancer. Atossa had $57.9 million in cash and no debt as of June 30, 2025.
(Z)-endoxifen shows equivalent anti-estrogen activity to tamoxifen but avoids CYP2D6 metabolism variability issues affecting up to 20% of women. The drug achieves target concentrations within hours versus weeks for tamoxifen, potentially offering a more predictable and faster-acting therapy.
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.