Appointed key leadership to drive (Z)-endoxifen development and evolve pathway to commercialization
SEATTLE, Nov. 12, 2025 /PRNewswire/ -- Atossa Therapeutics, Inc. (NASDAQ:ATOS) (Atossa or the Company), a clinical-stage biopharmaceutical company developing proprietary innovative medicines in areas of significant unmet medical need in oncology, today announces its financial results for the third quarter ended September 30, 2025 and provides an update on recent corporate developments.
"We continue to make meaningful and measurable progress across our (Z)-endoxifen development strategy in oncology," stated Dr. Steven Quay, Atossa Therapeutics' Chairman and CEO. "Initiatives include enhanced efficiency, focus and financial discipline with our programs, and readiness as we work to evolve into a commercial company. With a strong balance sheet, a strategically focused team, and the true desire to provide a solution for the millions of women worldwide suffering from breast cancer, we believe we are well-positioned to execute on our planned upcoming IND submission and advance our clinical programs toward key value-creating milestones."
Clinical & Regulatory Developments
Requested a Type C meeting with the U.S. Food and Drug Administration (FDA) to discuss regulatory strategy aimed at accelerating development of (Z)-endoxifen in breast cancer risk reduction - In September 2025, Atossa requested a Type C meeting with the FDA to discuss a regulatory strategy aimed at accelerating development of low-dose (Z)-endoxifen for breast cancer risk reduction. On November 6, 2025, Atossa received preliminary written comments from the FDA regarding the regulatory path for (Z)-endoxifen. The Company expects to meet with the FDA on November 17, 2025, to discuss a development plan intended to support filing an NDA, including the potential use of expedited programs where eligible. Atossa will evaluate any implications for its plans and timelines following receipt of FDA meeting minutes, which are expected to be available in December 2025. This follows the recommendation of Atossa's team of experts -- including an internationally recognized FDA law firm and senior regulatory affairs experts -- engaged to review the Company's extensive (Z)-endoxifen data and the considerable published scientific literature on (Z)-endoxifen to evaluate whether existing evidence could support a faster regulatory path in breast cancer risk-reduction. Atossa has now filed this meeting request to align with the FDA on the requirements needed to complete a New Drug Application (NDA) and expects to update shareholders on the outcome of the meeting before year end 2025, based on standard agency timelines and subject to a timely resolution to the ongoing U.S. government shutdown. While there can be no assurance of a favorable outcome, a successful alignment with the FDA could materially shorten development timelines and reduce future clinical costs.
Streamlined EVANGELINE breast cancer clinical trial to prioritize potential 2026 NDA-enabling activities - In October 2025, Atossa amended its Phase 2 EVANGELINE study of (Z)-endoxifen in premenopausal women with newly diagnosed early-stage ER+/HER2- breast cancer. The amended, non-registrational study design is expected to accelerate objective readouts while reducing projected future study costs, consistent with Atossa's focus on extending operating runway and deploying capital where it is most impactful. In 2026, Atossa plans to concentrate its resources on near-term, NDA-enabling activities for investigational (Z)-endoxifen.
Named Janet R. Rea, MSPH, as Senior Vice President, R&D to accelerate (Z)-endoxifen toward key regulatory milestones. Appointed Mark Daniel, CPA, as Chief Financial Officer to lead finance, systems, and capital strategy for commercial readiness - In October 2025, Atossa appointed Janet R. Rea, MSPH to its newly created position Senior Vice President, R&D. Ms. Rea brings more than two decades of strategic research and clinical development expertise, with a success record for regulatory approvals, to oversee late-stage (Z)-endoxifen programs with near term priorities that include planned upcoming FDA submissions, interactions, and defining a pathway to commercialization. Also in October 2025, Atossa named Mark Daniel, CPA (WA; inactive), as Chief Financial Officer. Mr. Daniel is a senior finance leader with more than 25 years of experience building the forecasting cadence, systems, and public-company discipline that support revenue scale in global life-science businesses. He has overseen weekly revenue forecasting in partnership with commercial leadership, managed operating expense budgets exceeding $200 million, implemented and certified Sarbanes-Oxley (SOX) controls, and led programs delivering over $50 million in cost savings.
Selected PSI as Contract Research Organization (CRO) for planned pivotal dose ranging study of (Z)-endoxifen in metastatic breast cancer (mBC) - In August 2025, Atossa selected PSI, a leading global CRO, to operationalize and manage its planned (Z)-endoxifen monotherapy dose-ranging study in women with mBC. The study was designed following guidance from the FDA and is intended to directly inform a subsequent Phase 3 trial. The global Phase 2, multi-center dose-ranging study is designed to evaluate (Z)-endoxifen monotherapy for safety, pharmacokinetics/pharmacodynamics, and preliminary anti-tumor activity. Patient enrollment is expected to follow the planned Investigational New Drug (IND) filing in Q4 2025, with topline data anticipated in 2026.
Highlighted progress in RECAST™ DCIS platform trial, In October 2025, Atossa announced that Laura J. Esserman, MD, MBA, Professor of Surgery and Radiology at the University of California, San Francisco and Principal Investigator of RECAST™, will speak at the Early Detection Research Conference in Portland, OR, about the Company's collaborative work in the RECAST platform trial for ductal carcinoma in situ (DCIS), a biologically heterogeneous, non-invasive breast condition that can progress to invasive breast cancer in a subset of patients. DCIS represents a large, under-served market that is commonly treated like invasive cancer (surgery ± radiation ± endocrine therapy). Demonstrating that a biomarker-guided, non-surgical approach is safe and effective could potentially reshape standard of care and expand use of oral endocrine agents in early-stage disease management. The platform design enables parallel testing of multiple agents, including Atossa's (Z)-endoxifen, with common imaging and biomarker endpoints to generate comparative signals that can inform registration strategies. The Company believes that early imaging response, biomarker correlation, and active-surveillance suitability rates by arm create interim readout opportunities that can help de-risk later-stage programs and guide payer-relevant health-economic modeling. RECAST is sponsored by Quantum Leap Healthcare Collaborative with research support from NIH and industry partners. This shared-infrastructure model can help accelerate enrollment, broaden site access, and optimize capital efficiency.
Intellectual Property & Patent Portfolio
New Israel Patent - In October 2025, Atossa announced key progress in its global intellectual-property strategy for (Z)-endoxifen, including the issuance of an Israeli patent and continued patent renewals that reinforce protection for the Company's lead program across major jurisdictions. The Israeli patent (No. 304863), titled, "Methods for Making and Using Endoxifen," was granted on July 2, 2025, with priority to multiple U.S. provisional applications filed in 2017–2018.
Recent Patent Challenges - Two of Atossa's patents are currently the subject of post–grant challenges (i.e., U.S. Patent Nos. 11,261,151 and 12,071,391), which may result in modification or invalidation of certain patent claims; however, such proceedings are common for high–value pharmaceutical IP, and we remain confident in our ability to vigorously defend these patents. The majority of Atossa's intellectual property is unaffected. Atossa holds four additional issued U.S. patents with claims to endoxifen—U.S. Patent Nos. 11,680,036, 12,201,591, 12,275,684, and 12,281,056—with over 200 total claims covering proprietary manufacturing methods, stable crystalline forms, and multiple sustained–release and enteric oral formulations of (Z)–endoxifen. We believe that these patents, along with pending applications worldwide, provide substantial additional protection for our lead program.
Strategic Outlook & Upcoming Milestones
Atossa remains focused on executing its breast cancer development strategy. Key upcoming deliverables include:
Working with the FDA on regulatory strategies for breast cancer indications beyond metastatic breast cancer, including women in the adjuvant setting, patients with DCIS, and use in reducing the incidence of breast cancer in high-risk women.
Targeting potential IND submission in Q4 2025, in alignment with feedback under the FDA Project Optimus initiative.
Advancing enrollment and data generation from ongoing Phase 2 trials.
Comparison of Three and Nine Months Ended September 30, 2025 and 2024
Operating Expenses. Total operating expenses were $9.3 million and $25.7 million for the three and nine months ended September 30, 2025, respectively, which was an increase of $2.9 million and $5.2 million from total operating expenses for the three and nine months ended September 30, 2024 of $6.4 million and $20.5 million, respectively. Factors contributing to the increased operating expenses in the three and nine months ended September 30, 2025 are explained below.
Research & Development (R&D) Expenses. The following table provides a breakdown of major categories within R&D expenses for the three and nine months ended September 30, 2025 and 2024, together with the dollar change and percentage change in those categories (dollars in thousands):
For the Three Months Ended September 30,
For the Nine Months Ended September 30,
2025
2024
Increase
% Increase
2025
2024
Increase
% Increase
Research and Development Expense
Clinical and non-clinical trials
$
4,318
$
2,490
$
1,828
73 %
$
11,154
$
7,875
$
3,279
42 %
Compensation
723
701
22
3 %
2,459
2,006
453
23 %
Professional fees and other
329
221
108
49 %
1,416
833
583
70 %
Research and Development Expense Total
$
5,370
$
