ATOS

SEATTLE, Aug. 7, 2026 /PRNewswire/ -- Atossa Therapeutics, Inc. (Nasdaq: ATOS) (Atossa or the Company), a clinical-stage biopharmaceutical company developing novel therapies in oncology and other areas of high unmet clinical need, today announced its financial results and provided an update on recent corporate developments for the second quarter ended June 30, 2026. "During the quarter, we executed well across the business," stated Dr. Steven Quay, M.D., Ph.D., Atossa Therapeutics' President and Chief Executive Officer. "We continued to advance the scientific rationale for (Z)-endoxifen's potential in rare pediatric diseases, such as Duchenne Muscular Dystrophy and McCune-Albright Syndrome, while also strengthening its clinical and scientific foundation in breast cancer, all through new data presented at important industry conferences, including ASCO and AACR, as well as publications in well-regarded peer-reviewed journals, Degenerative Neurological and Neuromuscular Disease and npj Breast Cancer." Dr. Quay continued, "These accomplishments, together with additional capital from our registered direct offering, underscore the breadth of potential we see for (Z)-endoxifen, and investors' support in our ability to continue advancing our programs." Second Quarter 2026 & Recent Highlights Rare Diseases Atossa Participated at the 2026 American Association for Cancer Research (AACR) Special Conference in Cancer Research: Cancer Evolution The Company Announced Acceptance of Manuscript Highlighting the Utrophin-Modulation Potential of (Z)-Endoxifen in Duchenne Muscular Dystrophy (DMD) Oncology The Company Published Manuscript Highlighting the Anti-cancer Activity of (Z)-Endoxifen-related Compounds Atossa Participated in the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting Corporate Atossa Strengthened its Balance Sheet with a Registered Direct Offering, Potentially Providing Up to $16.5 Million in Gross Proceeds Financial Results for the Second Quarter Ended June 30, 2026 Operating Expenses. Total operating expenses were $8.7 million and $18.6 million for the three and six months ended June 30, 2026, respectively, which was a decrease of $0.3 million and an increase of $2.1 million from total operating expenses for the three and six months ended June 30, 2025 of $9.0 million and $16.5 million, respectively. Factors contributing to the changes in operating expenses during the three and six months ended June 30, 2026 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 six months ended June 30, 2026 and 2025, together with the dollar change and percentage change in those categories (dollars in thousands): As (Z)-endoxifen is our only product candidate for which we currently incur R&D expenses, we have not further disaggregated R&D expenses by product candidate: Clinical and non-clinical trial expenses decreased $0.6 million for the three months ended June 30, 2026, compared to the three months ended June 30, 2025, primarily due to a decrease of $1.0 million in spend on preclinical trials that concluded in the prior period, partially offset by an increase in expense due to higher enrollment in clinical trials of $0.2 million and an increase in drug development costs of $0.3 million in the current period. Clinical and non-clinical trial expenses increased $0.4 million for the six months ended June 30, 2026, compared to the six months ended June 30, 2025, due to an increase in expense related to clinical trial enrollments of $1.5 million and an increase in drug development costs of $0.7 million, partially offset by a $1.8 million decrease in expenses related to preclinical work completed in 2025. The increase in R&D compensation expenses of $0.1 million and $0.2 million for the three and six months ended June 30, 2026, respectively, compared to the three and six months ended June 30, 2025, was due primarily to increases in non-cash stock-based compensation expense of $0.1 million. The decrease in R&D professional fees and other of $0.1 million and $0.5 million for the three and six months ended June 30, 2026, respectively, compared to the three and six months ended June 30, 2025, was primarily attributable to a decrease in regulatory consulting fees in the 2026 periods related to our (Z)-endoxifen program as compared to the same periods in the prior year. General and Administrative (G&A) Expenses. The following table provides a breakdown of major categories within G&A expenses for the three and six months ended June 30, 2026 and 2025, together with the dollar change and percentage change in those categories (dollars in thousands): The decrease in G&A compensation expenses of $0.3 million and $0.5 million for the three and six months ended June 30, 2026, respectively, compared to the three and six months ended June 30, 2025, was due primarily to a decrease in headcount in the current year periods compared to the same periods in the prior year. The increase in G&A professional fees and other of $0.6 million and $2.6 million for the three and six months ended June 30, 2026, respectively, compared to the three and six months ended June 30, 2025, was due primarily to higher legal fees of $0.7 million and $2.5 million, for the three and six months ended June 30, 2026, respectively, related to our patent litigation matters, which have now been settled, as well as fees associated with management of our intellectual property portfolio and legal costs related to our SEC compliance and other stock administration matters incurred during the current year periods. Interest Income. Interest income was $0.2 million and $0.5 million for the three and six months ended June 30, 2026, respectively, and decreased $0.4 million and $0.8 million compared to the three and six months ended June 30, 2025, respectively. The decrease was due primarily to lower average cash balances invested in our money market account during the current year periods relative to the same periods in the prior year. About Atossa Therapeutics Atossa Therapeutics, Inc. (Nasdaq: ATOS) is a clinical-stage biopharmaceutical company developing innovative medicines in oncology and other areas of significant unmet need. The Company's lead product candidate, (Z)-endoxifen, is currently in development across several clinical settings. (Z)-Endoxifen is a potent Selective Estrogen Receptor Modulator/Degrader (SERM/D) with demonstrated activity across multiple mechanisms of interest. Atossa is evaluating its potential applications in oncology and rare diseases. The Company's proprietary oral formulation has shown a favorable safety profile and pharmacology distinct from tamoxifen, including ER-targeted effects and PKC inhibition. Atossa's (Z)-endoxifen is not approved for any indication. Atossa has received Orphan Drug Designation from the U.S. Food and Drug Administration (FDA) for (Z)-endoxifen for the treatment of Duchenne Muscular Dystrophy, as well as Rare Pediatric Disease (RPD) designation for (Z)-endoxifen for the treatment of both Duchenne Muscular Dystrophy and McCune-Albright Syndrome. Upon approval of a qualifying marketing application, drugs with RPD designation may be eligible for a Priority Review Voucher (PRV), which can be used to obtain priority review for a future application or may be sold or transferred to another sponsor. In the last 18–24 months, disclosed PRV sales have ranged from $100–$220 million. Atossa's (Z)-endoxifen program is supported by a growing global intellectual property portfolio, including multiple recently issued U.S. patents and numerous pending applications worldwide. More information is available at https://atossatherapeutics.com. Forward Looking Statements This press release contains certain "forward-looking statements" within the meaning of applicable securities laws, including but not limited to, our 2026 outlook and our expectations regarding the Company's development and regulatory strategy and related milestones, the potential indications that the Company may pursue for (Z)-endoxifen, the potential role of (Z)-endoxifen and (Z)-endoxifen-related compounds in endocrine therapies, the potential for (Z)-endoxifen to receive regulatory approval and the timing thereof, the Company's progress across its pipeline and potential commercialization, the strength of the Company's patent portfolio, the Company's potential eligibility for and the value of a Rare Pediatric Disease PRV, and the potential market and growth opportunities for the Company. Words such as "expect," "potential," "continue," "may," "will," "should," "could," "would," "seek," "intend," "plan," "estimate," "anticipate," "believe," "design," "predict," "future," or other similar expressions or statements regarding intent, belief or current expectations, are forward-looking statements. Forward-looking statements in this press release are subject to risks and uncertainties that may cause actual results, outcomes, or the timing of actual results or outcomes to differ materially from those projected or anticipated, including, without limitation, risks and uncertainties associated with: our ability to successfully execute our strategy to shorten our clinical development timelines and pursue a DMD or MAS indication or other indications for our lead program, (Z)-endoxifen; expected timing, completion and results of our preclinical studies, clinical trials, and research and development programs; the potential clinical significance of preclinical data and the unpredictable relationship between preclinical study results and clinical study results; the timing or likelihood of regulatory filings and approvals; the outcome or timing of necessary regulatory approvals; our ability to receive orphan-drug exclusivity for (Z)-endoxifen for MAS; our ability to maintain compliance with Nasdaq listing requirements; our ability to establish and maintain intellectual property rights covering our products; the impact of general macroeconomic conditions on our business; our ability to raise capital; and other risks and uncertainties detailed from time to time in Atossa's filings with the SEC, including, without limitation, its Annual Reports on Form 10-K and Quarterly Reports on Form 10-Q. The market value of a PRV is variable and subject to a number of factors beyond our control and reported past PRV sale amounts are not necessarily indicative of PRV sale amounts in the future. Forward-looking statements are presented as of the date of this press release. Except as required by law, we do not intend to update any forward-looking statements. View original content to download multimedia:https://www.prnewswire.com/news-releases/atossa-therapeutics-reports-second-quarter-2026-financial-results-and-provides-a-corporate-update-302845837.html

SEATTLE, May 8, 2026 /PRNewswire/ -- Atossa Therapeutics, Inc. (Nasdaq: ATOS) (Atossa or the Company), a clinical-stage biopharmaceutical company developing novel therapies in oncology and other areas of high unmet clinical need, today announces its financial results and provides an update on recent corporate developments for the first quarter ended March 31, 2026. "During the quarter, we made meaningful progress advancing our (Z)-endoxifen development strategy across both oncology and rare disease indications," stated Dr. Steven Quay, M.D., Ph.D., Atossa Therapeutics' President and Chief Executive Officer. "We continued to advance (Z)-endoxifen in the clinic for the treatment of breast cancer, while also generating data to support its potential in rare diseases, including Duchenne Muscular Dystrophy (DMD) and McCune-Albright Syndrome. Importantly, we secured both Orphan Drug and Rare Pediatric Disease designations from the FDA for (Z)-endoxifen in DMD, and subsequently we've received Rare Pediatric Disease designation from the FDA for McCune-Albright Syndrome, reinforcing the potential of our programs in areas of high unmet need. Building on this momentum, we remain focused on identifying additional indications where our platform can deliver meaningful therapeutic benefit to patients with limited treatment options." Dr. Quay continued, "Our balance sheet remains strong, positioning us to continue to execute across our strategic plans, and deliver value to shareholders in upcoming quarters." First Quarter 2026 & Recent Highlights Atossa Therapeutics Presented Encouraging Pre-clinical data for (Z)-Endoxifen in DMD at the MDA Clinical & Scientific Conference - In an oral presentation on March 11, 2026, the Company demonstrated that (Z)-endoxifen improved muscle strength, increased lean mass, and reduced biochemical markers of muscle damage in dystrophic mouse models. We believe these data support advancement into the clinical setting. Atossa Therapeutics Received FDA Orphan Drug Designation for (Z)-Endoxifen for the Treatment of DMD - In January 2026, Atossa announced that the U.S. Food and Drug Administration (FDA) Office of Orphan Products Development (OOPD) granted Orphan Drug Designation to (Z)-endoxifen for the treatment of DMD. Orphan Drug Designation is granted by the FDA to therapies intended to treat rare diseases or conditions. The designation is designed to encourage drug development by offering certain potential incentives, such as regulatory support and, if the product ultimately receives marketing approval for the designated indication, eligibility for a period of market exclusivity. The Company previously received Rare Pediatric Disease (RPD) designation for (Z)-endoxifen for the treatment of DMD. Atossa Therapeutics Received FDA RPD Designation for (Z)-Endoxifen for McCune-Albright Syndrome - In early May 2026, Atossa announced that the FDA had granted RPD for (Z)-Endoxifen for McCune-Albright Syndrome, which is the Company's second of such designations received in the last 6 months for rare diseases with currently unmet need. Upon approval of a qualifying marketing application, drugs with RPD designation may be eligible for a Priority Review Voucher (PRV), which can be used to obtain priority review for a future application or may be sold or transferred to another sponsor. In the last 18 to 24 months, disclosed PRV sales have ranged from $100–$205 million. Atossa Therapeutics Strengthened Clinical Leadership Team with the Addition of Two Experienced Biopharma Executives - Atossa announced the engagement of Kathy Puyana Theall, M.D. as Medical Director - Breast Oncology, and Adebola Giwa, M.D. as Medical Director - Rare Diseases. We believe the addition of these two highly experienced physicians and clinical leaders meaningfully strengthens Atossa's ability to execute on its (Z)-endoxifen development strategy across both breast cancer and rare disease programs, including DMD and McCune-Albright Syndrome, as the Company advances toward key clinical and regulatory milestones. Financial Results for the First Quarter Ended March 31, 2026 Operating Expenses. Total operating expenses were $9.9 million for the three months ended March 31, 2026, which was an increase of $2.5 million, from total operating expenses for the three months ended March 31, 2025 of $7.4 million. Factors contributing to the increased operating expenses in the three months ended March 31, 2026 are explained below. Research & Development (R&D) Expenses. The following table provides a breakdown of major categories within R&D expenses for the three months ended March 31, 2026 and 2025, together with the dollar change and percentage change in those categories (dollars in thousands): As (Z)-endoxifen is our only product candidate for which we currently incur R&D expenses, we have not further disaggregated R&D expenses by product candidate: Clinical and non-clinical trial expenses increased $1.0 million for the three ended March 31, 2026, compared to the three months ended March 31, 2025, due to increases in spend related to our (Z)-endoxifen trials, including drug development costs. The increase in R&D compensation expenses of $0.1 million for the three months ended March 31, 2026 compared to the three months ended March 31, 2025, was due primarily to increases in non-cash stock-based compensation expense of $0.1 million. The decreases in R&D professional fees and other of $0.4 million for the three months ended March 31, 2026, compared to the three months ended March 31, 2025, were primarily attributable to lower regulatory consulting fees in the first quarter of 2026 related to our (Z)-endoxifen program as compared to the same quarter in the prior year. General and Administrative (G&A) Expenses. The following table provides a breakdown of major categories within G&A expenses for the quarter ended March 31, 2026 and 2025, together with the dollar change and percentage change in those categories (dollars in thousands): The decrease in G&A compensation expenses of $0.2 million for the three months ended March 31, 2026, compared to the three months ended March 31, 2025, was due primarily to a decrease in headcount in the current year period compared to the same period in the prior year. The increase in G&A professional fees and other of $2.0 million for the three months ended March 31, 2026, compared to the three months ended March 31, 2025, was due primarily to higher legal fees of $1.8 million, related to our ongoing patent litigation activity, which has subsequently been settled, as well as fees associated with management of our intellectual property portfolio and other legal matters. Interest Income. Interest income of $0.3 million for the quarter ended March 31, 2026 represented a decrease of $0.4 million compared to the prior year period. The decrease was due primarily to lower average cash balances invested in our money market account during the current year period relative to the same period in the prior year. About Atossa Therapeutics Atossa Therapeutics, Inc. (Nasdaq: ATOS) is a clinical-stage biopharmaceutical company developing innovative medicines in oncology and other areas of significant unmet need. The Company's lead product candidate, (Z)-endoxifen, is currently in development across several clinical settings. (Z)-Endoxifen is a potent Selective Estrogen Receptor Modulator/Degrader (SERM/D) with demonstrated activity across multiple mechanisms of interest. Atossa is evaluating its potential applications in oncology and rare diseases. The Company's proprietary oral formulation has shown a favorable safety profile and pharmacology distinct from tamoxifen, including ER-targeted effects and PKC inhibition. Atossa's (Z)-endoxifen is not approved for any indication. Atossa has received Orphan Drug Designation from the U.S. Food and Drug Administration (FDA) for (Z)-endoxifen for the treatment of Duchenne Muscular Dystrophy, as well as Rare Pediatric Disease (RPD) designation for (Z)-endoxifen for the treatment of both Duchenne Muscular Dystrophy and McCune-Albright Syndrome. Upon approval of a qualifying marketing application, drugs with RPD designation may be eligible for a Priority Review Voucher (PRV), which can be used to obtain priority review for a future application or may be sold or transferred to another sponsor. In the last 18–24 months, disclosed PRV sales have ranged from $100–$205 million. Atossa's (Z)-endoxifen program is supported by a growing global intellectual property portfolio, including multiple recently issued U.S. patents and numerous pending applications worldwide. More information is available at https://atossatherapeutics.com. Forward Looking Statements This press release contains certain "forward-looking statements" within the meaning of applicable securities laws, including but not limited to, our 2026 outlook and our expectations regarding the Company's development and regulatory strategy and related milestones, the potential indications that the Company may pursue for (Z)-endoxifen, the potential for (Z)-endoxifen to receive regulatory approval and the timing thereof, the Company's progress across its pipeline and potential commercialization, the strength of the Company's patent portfolio, the Company's potential eligibility for and the value of a Rare Pediatric Disease Priority Review Voucher (PRV), and the potential market and growth opportunities for the Company. Words such as "expect," "potential," "continue," "may," "will," "should," "could," "would," "seek," "intend," "plan," "estimate," "anticipate," "believe," "design," "predict," "future," or other similar expressions or statements regarding intent, belief or current expectations, are forward-looking statements. Forward-looking statements in this press release are subject to risks and uncertainties that may cause actual results, outcomes, or the timing of actual results or outcomes to differ materially from those projected or anticipated, including, without limitation, risks and uncertainties associated with: our ability to successfully execute our strategy to shorten our clinical development timelines and pursue a DMD or McCune-Albright Syndrome indication or other indications for our lead program, (Z)-endoxifen; expected timing, completion and results of our preclinical studies, clinical trials, and research and development programs; the unpredictable relationship between preclinical study results and clinical study results; the timing or likelihood of regulatory filings and approvals; the outcome or timing of necessary regulatory approvals; our ability to receive orphan-drug exclusivity for (Z)-endoxifen for DMD; our ability to maintain compliance with Nasdaq listing requirements; our ability to establish and maintain intellectual property rights covering our products; the impact of general macroeconomic conditions on our business; our ability to raise capital; and other risks and uncertainties detailed from time to time in Atossa's filings with the SEC, including, without limitation, its Annual Reports on Form 10-K and Quarterly Reports on Form 10-Q. The market value of a PRV is variable and subject to a number of factors beyond our control and reported past PRV sale amounts are not necessarily indicative of PRV sale amounts in the future. Forward-looking statements are presented as of the date of this press release. Except as required by law, we do not intend to update any forward-looking statements. View original content to download multimedia:https://www.prnewswire.com/news-releases/atossa-therapeutics-reports-first-quarter-2026-financial-results-and-provides-a-corporate-update-302766510.html

SEATTLE, March 25, 2026 /PRNewswire/ -- Atossa Therapeutics, Inc. (Nasdaq: ATOS) (Atossa or the Company), a clinical-stage biopharmaceutical company developing novel therapies in oncology and other areas of high unmet clinical need, today announces its financial results for the fourth quarter and year ended December 31, 2025 and provides an update on recent corporate developments. "While we have consistently made meaningful and measurable progress across our (Z)-endoxifen development strategy in oncology over the last 12 months, we continue to explore the best opportunities to leverage the technology where it may help to address serious health conditions and unmet medical needs. As we continue to keep a careful eye on opportunities in the breast cancer space, we are also diligently working to advance (Z)-endoxifen in certain rare disease indications, such as Duchenne Muscular Dystrophy (DMD) and McCune-Albright Syndrome (MAS)," stated Dr. Steven Quay, M.D., Ph.D., Atossa Therapeutics' President and Chief Executive Officer. "To date, we have published work that identifies the opportunity for (Z)-endoxifen, while achieving both FDA Rare Pediatric Disease and Orphan Drug designations. We believe these FDA designations are important for future development as they both help to speed the FDA review process as well as provide potential financial benefits in the future." "In the meantime, we are consciously aligning our resources with the demands of potential commercialization, even as we have added new professionals to our team to help drive both our rare disease and breast cancer programs forward. With a strong balance sheet and a strategically focused team, we believe we are well-positioned to execute and advance our clinical programs toward key value-creating milestones," concluded Dr. Quay. Clinical & Regulatory Progress & Announcements Atossa Highlighted Emerging Opportunity for (Z)-Endoxifen in Duchenne Muscular Dystrophy, Including Symptomatic Female Carriers, Following Peer-Reviewed Publication and Scientific Presentation - The published article, "A Hypothesized Therapeutic Role of (Z)-Endoxifen in Duchenne Muscular Dystrophy (DMD)," surveys the DMD treatment landscape and details how (Z)-endoxifen's pharmacology could address multiple downstream drivers of disease, including inflammation, fibrosis, calcium dysregulation, mitochondrial dysfunction, and lipid abnormalities. The paper emphasizes (Z)-endoxifen's direct estrogen-receptor (ER) modulation, allosteric inhibition of PKC (notably PKC-β1), and effects along AKT/mTOR and NF-κB axes, mechanisms that together may help slow disease progression when used as an adjunct to standard care. Notably, the authors underscore (Z)-endoxifen's potential to deliver more consistent therapeutic exposures than tamoxifen by bypassing CYP2D6 metabolic variability, an important limitation of the pro-drug approach. As illustrated in the mechanistic diagram, page 7 of the publication, the paper maps (Z)-endoxifen's ER-dependent and ER-independent signaling effects relevant to dystrophic muscle. Atossa Therapeutics Received FDA Rare Pediatric Disease Designation for (Z)-Endoxifen for Duchenne Muscular Dystrophy - In December 2025, Atossa announced that the U.S. Food and Drug Administration ("FDA") granted Rare Pediatric Disease ("RPD") designation to (Z)-endoxifen for the treatment of DMD. RPD designation is granted to drug candidates intended to treat serious or life-threatening diseases that primarily affect individuals from birth to 18 years of age. Upon approval of a qualifying marketing application, drugs with RPD designation may be eligible for a Priority Review Voucher ("PRV"), which can be used to obtain priority review for a future application or may be sold or transferred to another sponsor. In the last 18–24 months, disclosed PRV sales have ranged from $100–$200 million. Atossa Therapeutics Won the 2025 Clinical Trials Arena Research and Development Excellence Award in Precision Endocrine Therapy Category - In December 2025, Atossa announced that it had been selected as a winner of the 2025 Clinical Trials Arena Excellence Awards. The Company was honored with the Research and Development Award in the Precision Endocrine Therapy category. Atossa earned this recognition for its innovative work advancing (Z)-endoxifen, its lead precision-engineered endocrine therapy. (Z)-endoxifen is a potent selective estrogen receptor modulator/degrader (SERM/D) with additional PKCβ1 inhibition, designed to provide consistent systemic exposure independent of CYP2D6 metabolism. The therapy is being evaluated across metastatic, neoadjuvant, adjuvant, and breast cancer risk-reduction settings, with an emerging application in DMD. Atossa Therapeutics Received FDA Orphan Drug Designation for (Z)-Endoxifen for the Treatment of Duchenne Muscular Dystrophy - In January 2026, Atossa announced that the U.S. Food and Drug Administration ("FDA") Office of Orphan Products Development ("OOPD") granted Orphan Drug Designation to (Z)-endoxifen for the treatment of DMD. Orphan Drug Designation is granted by FDA to therapies intended to treat rare diseases or conditions. The designation is designed to encourage drug development by offering certain potential incentives, such as regulatory support and, if the product ultimately receives marketing approval for the designated indication, eligibility for a period of market exclusivity. Atossa Announces Additions to Management Team Atossa Therapeutics Strengthened Clinical Leadership Team with the Addition of Two Experienced Biopharma Executives - Atossa announced the engagement of Kathy Puyana Theall, M.D., as Medical Director - Breast Oncology, and Adebola Giwa, M.D., as Medical Director - Rare Diseases. We believe the addition of these two highly experienced physicians and clinical leaders meaningfully strengthens Atossa's ability to execute on its (Z)-endoxifen development strategy across both breast cancer and rare disease programs, including DMD and MAS, as the Company advances toward key clinical and regulatory milestones. Comparison of Years-Ended December 31, 2025 and 2024 Operating Expenses. Total operating expenses were $37.1 million for the year ended December 31, 2025, which was an increase of $9.5 million, from the year ended December 31, 2024 of $27.6 million. Factors contributing to the increased operating expenses in the year ended December 31, 2025 are explained below. Research & Development Expenses. The following table provides a breakdown of major categories within R&D expenses for the years ended December 31, 2025 and 2024, together with the dollar change in those categories (dollars in thousands): As (Z)-endoxifen is our only product candidate for which we currently incur R&D expenses, we have not further disaggregated R&D expenses by product candidate: Clinical and pre-clinical trial expense increased $6.1 million for the year ended December 31, 2025 compared to the prior year due to an increase in spending for the (Z)-endoxifen trials, including an increase in drug development costs. The increase in R&D compensation expense of $0.3 million for the year ended December 31, 2025 compared to the prior year was due primarily to an increase in cash compensation expense of $0.4 million resulting from an increase in headcount. This increase was partially offset by a non-cash stock-based compensation expense decrease of $0.1 million compared to the prior year due to the weighted average fair value of stock options amortizing in 2025 being lower than 2024. The increase in R&D professional fees and other of $0.7 million for the year ended December 31, 2025 compared to the prior year was primarily attributable to higher regulatory consulting fees in 2025 related to our (Z)-endoxifen program. General and Administrative (G&A) Expenses. The following table provides a breakdown of major categories within G&A expenses for the years ended December 31, 2025 and 2024, together with the dollar change in those categories (dollars in thousands): The increase in G&A compensation expense of $0.6 million for the year ended December 31, 2025 compared to the prior year was due to an increase in both cash compensation expense of $0.2 million and non-cash stock-based compensation expense of $0.4 million. The increase in cash compensation expense compared to the prior year was primarily driven by salary, bonus and severance costs for a former executive of $0.4 million, partially offset by a decrease in cash bonus related to terminations and reductions in expected bonus payouts in 2025. The non-cash stock-based compensation expense increase was driven by an increase in the fair value of grants to members of our Board of Directors (the Board) which amortize over one year. G&A professional fees and other expenses increased by $2.0 million for the year ended December 31, 2025 compared to the prior year due primarily to an increase in legal fees of $1.8 million for the year ended December 31, 2025 driven by the costs for our ongoing litigation and patent defense which increased by $1.6 million compared to the prior year. Investor relations expense increased by $0.3 million for the year ended December 31, 2025 compared to the prior year due to changes in investor outreach and broader investor relations strategy. Partially offsetting the increases, our accounting fees decreased by $0.3 million for the year ended December 31, 2025 compared to the prior year due to the inclusion of higher auditor fees associated with our 2024 Registration Statement on Form S-3 and our at the market offering facility. The decrease in G&A insurance expense of $0.2 million for the year ended December 31, 2025 compared to the prior year was due primarily to lower negotiated insurance premiums associated with our Director's and Officer's insurance and other key insurance policies in 2025. Interest Income. Interest income of $2.4 million for the year ended December 31, 2025 represented a decrease of $1.7 million compared to the prior year, and was due primarily to a decrease in the average funds invested in our money market account. Impairment Charge on Investment in Equity Securities. For the year ended December 31, 2024, we wrote down our Investment in equity securities by $1.7 million due to impairment of our investment in Dynamic Cell Therapies, Inc. About (Z)-Endoxifen (Z)-Endoxifen is a potent Selective Estrogen Receptor Modulator/Degrader (SERM/D) with demonstrated activity across multiple mechanisms of interest. Atossa is evaluating its potential applications in oncology and rare diseases. The Company's proprietary oral formulation has shown a favorable safety profile and pharmacology distinct from tamoxifen, including ER-targeted effects and PKC inhibition. Atossa's (Z)-endoxifen is not approved for any indication. Atossa's (Z)-endoxifen program is supported by a growing global intellectual property portfolio, including multiple recently issued U.S. patents and numerous pending applications worldwide. About Atossa Therapeutics Atossa Therapeutics, Inc. (Nasdaq: ATOS) is a clinical-stage biopharmaceutical company developing innovative medicines in oncology and other areas of significant unmet need. The Company's lead product candidate, (Z)-endoxifen, is currently in development across several clinical settings. More information is available at https://atossatherapeutics.com. Forward Looking Statements This press release contains certain "forward-looking statements" within the meaning of applicable securities laws, including but not limited to, our 2026 outlook and our expectations regarding the Company's development and regulatory strategy and related milestones, including potential Investigational New Drug submissions, the potential indications that the Company may pursue for (Z)-endoxifen, the potential for (Z)-endoxifen to receive regulatory approval and the timing thereof, the Company's progress across its pipeline and potential commercialization, the strength of the Company's patent portfolio, the Company's potential eligibility for the Rare Pediatric Disease Priority Review Voucher (PRV) program and the value of a PRV, and the potential market and growth opportunities for the Company. Words such as "expect," "potential," "continue," "may," "will," "should," "could," "would," "seek," "intend," "plan," "estimate," "anticipate," "believe," "design," "predict," "future," or other similar expressions or statements regarding intent, belief or current expectations, are forward-looking statements. Forward-looking statements in this press release are subject to risks and uncertainties that may cause actual results, outcomes, or the timing of actual results or outcomes to differ materially from those projected or anticipated, including, without limitation, risks and uncertainties associated with: our ability to successfully execute our strategy to shorten our clinical development timelines and pursue a DMD indication or other indications for our lead program, (Z)-endoxifen; expected timing, completion and results of our preclinical studies, clinical trials and research and development programs; the unpredictable relationship between preclinical study results and clinical study results; the timing or likelihood of regulatory filings and approvals; the outcome or timing of necessary regulatory approvals; our ability to receive orphan-drug exclusivity for (Z)-endoxifen for DMD; our ability to maintain compliance with Nasdaq listing requirements; our ability to establish and maintain intellectual property rights covering our products; the impact of general macroeconomic conditions on our business; our ability to raise capital; and other risks and uncertainties detailed from time to time in Atossa's filings with the SEC, including, without limitation, its Annual Reports on Form 10-K and Quarterly Reports on Form 10-Q. Forward-looking statements are presented as of the date of this press release. Except as required by law, we do not intend to update any forward-looking statements. View original content to download multimedia:https://www.prnewswire.com/news-releases/atossa-therapeutics-reports-fourth-quarter-and-year-end-2025-financial-results-and-provides-a-corporate-update-302725388.html

Company reports progress to file planned IND for (Z)-endoxifen in mBC with CRO selection and streamlined development programs for potential 2026-NDA enabling activities, including a Type C meeting with the FDA, to potentially accelerate (Z)-endoxifen in breast cancer risk reduction 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): As (Z)-endoxifen is our only product candidate for which we currently incur R&D expenses, we have not further disaggregated R&D expenses by product candidate: Clinical and non-clinical trial expenses increased $1.8 million and $3.3 million for the three and nine months ended September 30, 2025, respectively, compared to the three and nine months ended September 30, 2024, due to increases in spend related to our (Z)-endoxifen trials, including drug development costs. The increase in R&D compensation expenses of $0.5 million for the nine months ended September 30, 2025 compared to the nine months ended September 30, 2024, was primarily due to an increase in headcount. R&D compensation expense remained relatively flat for the three months ended September 30, 2025, compared to the same period in 2024. The increases in R&D professional fees and other of $0.1 million and $0.6 million for the three and nine months ended September 30, 2025, respectively, compared to the three and nine months ended September 30, 2024, were primarily attributable to higher regulatory consulting fees in the 2025 periods related to our (Z)-endoxifen program. General and Administrative (G&A) Expenses. The following table provides a breakdown of major categories within G&A 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): The increases in G&A compensation expenses of $0.1 million and $0.8 million for the three and nine months ended September 30, 2025, respectively, compared to the three and nine months ended September 30, 2024, were primarily due to increases in non-cash stock-based compensation expense of $0.1 million and $0.6 million, respectively. The increases in G&A professional fees and other of $0.8 million and $0.3 million for the three and nine months ended September 30, 2025, compared to the three and nine months ended September 30, 2024, were primarily due to increases in legal fees of $0.7 million and $0.5 million, respectively, related to higher patent-related activity as well as other legal matters, partially offset by decreases in investor relations costs of $0.3 million due to changes in the timing of investor outreach programs. Interest Income. Interest income was $0.6 million and $1.9 million for the three and nine months ended September 30, 2025, respectively, a decrease of $0.4 million and $1.3 million from interest income of $1.0 million and $3.2 million for the three and nine months ended September 30, 2024, respectively. The decreases were due to decreases in the average balance invested in our money market account. Impairment Charge on Investment in Equity Securities. For the nine months ended September 30, 2024, we wrote down our Investment in equity securities by $1.7 million due to the impairment of our investment in Dynamic Cell Therapies, Inc. (DCT). About (Z)-endoxifen (Z)-endoxifen is a highly potent Selective Estrogen Receptor Modulator/Degrader (SERM/D) with demonstrated ability to inhibit and potentially degrade estrogen receptors. It has shown activity even in tumors that have developed resistance to other endocrine therapies. Beyond its anti-estrogenic properties, (Z)-endoxifen also targets the oncogenic signaling pathway, protein kinase C beta 1 (PKCβ1), at clinically achievable blood and tumor levels. (Z)-endoxifen also seems to deliver comparable or superior bone-protective effects relative to tamoxifen. Atossa is developing a proprietary enteric oral formulation of (Z)-endoxifen that bypasses stomach acid, which would otherwise partially convert the active (Z)-isomer to its inactive (E)-form. We believe this innovation allows for optimal bioavailability and therapeutic integrity. Clinical studies have shown Atossa's (Z)-endoxifen to be well tolerated in both healthy women and those with breast cancer. In over 700 subjects (healthy volunteers and breast cancer patients) receiving doses up to 360 mg/day, no maximum tolerated dose (MTD) has been identified, supporting continued dose-range exploration. Atossa is actively pursuing what it believes are opportunities to accelerate its regulatory path with (Z)-endoxifen for use in several indications in which low dose (Z)-endoxifen could potentially help lower the risk of breast cancer. We expect to share more about the viability of this accelerated path and related milestones by the end of 2025. In addition, Atossa is continuing its ongoing development efforts for use of (Z)-endoxifen in metastatic breast cancer. The compound is currently being evaluated in three Phase 2 studies, one in DCIS and two in ER+/HER2- breast cancer. Further, monotherapy in DCIS and low risk cancer, and combination therapy in high-risk cancer, with Lilly's CDK4/6 inhibitor, Verzenio® (abemaciclib), are being investigated. Atossa's (Z)-endoxifen program is supported by a growing global intellectual property portfolio, including three recently issued U.S. patents and numerous pending applications worldwide. About Atossa Therapeutics Atossa Therapeutics, Inc. (Nasdaq: ATOS) is a clinical-stage biopharmaceutical company developing novel therapies in oncology, including (Z)-endoxifen, to improve outcomes for patients across the breast cancer continuum of care. Information about Atossa can be found at the website: https://atossatherapeutics.com/. Forward Looking Statements This press release contains certain information that may constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. We may identify these forward-looking statements by the use of words such as "expect," "potential," "continue," "may," "will," "should," "could," "would," "seek," "intend," "plan," "estimate," "anticipate," "believe," "design," "predict," "future," or other comparable words. All statements made in this press release that are not statements of historical fact, including statements regarding the Company's development strategy and related milestones, data related to the (Z)-endoxifen program, the safety, tolerability and efficacy of (Z)-endoxifen, the potential of (Z)-endoxifen as a breast cancer prevention and treatment agent, the potential indications that the Company may pursue for (Z)-endoxifen, the potential for (Z)-endoxifen to receive regulatory approval, including potential IND and NDA submissions, and related timing, benefits of the Company's strategy of pursuing a metastatic indication for (Z)-endoxifen, the expected design and enrollment of trials and timing of data and related publications, the Company's progress across its pipeline, the strength of the Company's patent portfolio and expectations regarding related litigation, and the potential market and growth opportunities for the Company, are forward-looking statements. Forward-looking statements in this press release are subject to risks and uncertainties that may cause actual results, outcomes, or the timing of actual results or outcomes, to differ materially from those projected or anticipated, including risks and uncertainties associated with: our ability to successfully execute our strategy to pursue a metastatic breast cancer indication for our lead program, (Z)-endoxifen, and to develop in parallel low dose (Z)-endoxifen for breast cancer reduction; our ability to shorten our clinical development timelines and reduce future clinical development costs through an accelerated path to filing an NDA, which is dependent on the timing and outcomes of submissions to and other interactions with the U.S. Food and Drug Administration (FDA); the expected timing of releasing data; any variation between interim or preliminary and final clinical results or analysis; actions and inactions by the FDA and foreign regulatory bodies; the outcome or timing of regulatory approvals needed by Atossa, including those needed to continue our planned (Z)-endoxifen trials; our ability to satisfy regulatory requirements; our ability to regain compliance or maintain compliance with the continued listing requirements of the Nasdaq Stock Market; our ability to successfully develop and commercialize new therapeutics; the success, costs and timing of our development activities, including our ability to successfully initiate or complete our clinical trials, including our (Z)-endoxifen trials; our anticipated rate of patient enrollment; our ability to contract with third-parties and their ability to perform adequately; our estimates on the size and characteristics of our potential markets; our ability to successfully defend litigation and other similar complaints and to establish and maintain intellectual property rights covering our products; whether we can successfully complete our clinical trial of oral (Z)-endoxifen in women with mammographic breast density and our trials of (Z)-endoxifen in women with breast cancer, and whether the studies will meet their objectives; our expectations as to future financial performance, expense levels and capital sources, including our ability to raise capital; our ability to attract and retain key personnel; our anticipated working capital needs and expectations around the sufficiency of our cash reserves; and other risks and uncertainties detailed from time to time in Atossa's filings with the Securities and Exchange Commission, including without limitation its Annual Reports on Form 10-K and Quarterly Reports on 10-Q. Forward-looking statements are presented as of the date of this press release. Except as required by law, we do not intend to update any forward-looking statements, whether as a result of new information, future events or circumstances or otherwise. View original content to download multimedia:https://www.prnewswire.com/news-releases/atossa-therapeutics-reports-third-quarter-2025-financial-results-and-provides-a-corporate-update-302612557.html

FDA Provides Positive Feedback, Clears Path for Atossa to File IND for (Z)-Endoxifen in Metastatic Breast Cancer; FDA Indicates No Additional Toxicity Studies Required Strong I-SPY2 Results Reinforce Efficacy of Atossa's Monotherapy at 3-weeks SEATTLE, Aug. 12, 2025 /PRNewswire/ -- Atossa Therapeutics, Inc. (Nasdaq: ATOS) (Atossa or the Company), a clinical-stage biopharmaceutical company developing innovative medicines for breast cancer, today announced its financial results for the second quarter ended June 30, 2025 and provided an update on recent company developments. "Atossa continues to make meaningful and measurable progress across our pipeline, underscored by recent, highly constructive interactions with the FDA that further support our (Z)-endoxifen development strategy in metastatic breast cancer," stated Dr. Steven Quay, Chairman and CEO of Atossa Therapeutics. "With a strong balance sheet, we believe we are well-positioned to execute on our planned upcoming IND submission and advance our metastatic clinical program toward key value-creating milestones. We remain disciplined in our capital strategy and have deliberately chosen not to utilize our ATM facility at recent share price levels, which we believe significantly undervalue the true potential of our Company. As we progress toward multiple upcoming potential catalysts, we are confident that our focused execution, scientific rigor, and unwavering commitment to patients will demonstrate the substantial intrinsic value of Atossa and position (Z)-endoxifen to make a meaningful impact in the treatment of breast cancer." Clinical & Regulatory Developments Positive FDA Feedback on (Z)-Endoxifen Program - In July 2025, Atossa announced it received highly constructive written feedback from the U.S. Food and Drug Administration (FDA), supporting the Company's proposed dose optimization trial in estrogen receptor positive, human epidermal growth factor receptor 2 negative (ER+/HER2-) metastatic breast cancer and allowing the Company to meet the requirements of Project Optimus. The FDA agreed that existing clinical and nonclinical data are sufficient to initiate the monotherapy arm (Part A) of the study and agreed with the scientific rationale for combination therapy arms (Part B) using standard-of-care agents, such as CDK4/6 inhibitors, PI3K inhibitors, mTOR inhibitors, and capecitabine. The Agency also indicated that no additional general toxicity or neurotoxicity studies are required and confirmed that Atossa's cardiac safety assessment monitoring protocol is sufficient for the monotherapy portion of the trial. These developments support the Company's plan to file an Investigational New Drug (IND) application with the FDA, which is expected in Q4 2025. Clinical Trial Readouts & Scientific Validation I‑SPY 2 Endocrine Optimization Sub‑Study Results (Monotherapy with Low-Dose 10 mg (Z)-endoxifen) – In May 2025, Atossa released full results from the Phase 2 pilot within the I‑SPY 2 trial. Among 20 women with stage II/III ER+, HER2‑ breast cancer. Primary endpoint achieved with 95 percent of subjects completing at least 75 percent of planned dosing. Median Ki‑67 dropped from 10.5 percent at baseline to 5 percent by Week 3, with 65 percent achieving Ki‑67 ≤ 10 percent. Ki-67 is a widely used biomarker in pathology to assess the extent to which cancer cells are dividing and is often correlated with tumor behavior and prognosis. The POETIC (Peri-Operative Endocrine Therapy for individualized Care) trial, a large phase 3 study conducted in the UK and sponsored by the Institute of Cancer Research and the Royal Marsden NHS Foundation Trust, demonstrated that early changes in Ki-67 are strongly prognostic. Published in 2020, the trial showed that women with ER+/HER2− breast cancer whose Ki-67 levels fell from >10 percent at baseline to ≤10 percent after just two weeks of neoadjuvant aromatase inhibitor therapy had a 5-year recurrence rate of 8.4 percent, compared to 21.5 percent in those whose Ki-67 remained above 10 percent. Median functional tumor volume, as assessed by MRI, decreased by 77.7 percent from baseline to surgery, and the longest tumor diameter dropped by 36.8 percent from baseline to preoperative MRI. Safety was favorable: adverse events were predominantly Grade 1; vasomotor symptoms (hot flushes) and fatigue were most common. Only three Grade 3 events (two skin infections, one post‑procedural infection) occurred in a single patient and were deemed unrelated to the study drug; no Grade 4 or Grade 5 events were reported. I-SPY 2 - Endocrine Optimization Pilot Analysis (Combination therapy of 40 mg (Z)-endoxifen and Eli Lilly's abemaciclib) Patient recruitment continues at a faster rate than anticipated, with 41 patients initiated as of July 29, 2025. Other ongoing Phase 2 Programs - Atossa continues to evaluate (Z)-endoxifen in two other Phase 2 trials: one in women with ductal carcinoma in situ (DCIS) and one in women with ER+/HER2- breast cancer, as previously disclosed. Intellectual Property & Patent Portfolio New U.S. Patents - In mid‑May 2025, Atossa announced the issuance of U.S. Patent No. 12,281,056, containing 58 claims relating to the enteric oral formulations of (Z)-endoxifen, including features of improved purity, stability, and bioavailability. 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: Announcement of Contract Research Organization (CRO) selected to execute the metastatic dose ranging study in coordination with Atossa clinical personnel. Disclosure of dose-ranging trial design, including specifics on patient selection criteria and combination treatment backbone. Targeting 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. Working with the FDA on regulatory strategies for breast cancer indications beyond metastatic breast cancer, including treating women in the adjuvant setting, patients with DCIS, and in reducing the incidence of breast cancer in high-risk women. Comparison of Three and Six Months Ended June 30, 2025 and 2024 Operating Expenses. Total operating expenses were $9.0 million and $16.5 million for the three and six months ended June 30, 2025, respectively, which was an increase of $1.9 million and $2.4 million from total operating expenses for the three and six months ended June 30, 2024 of $7.1 million and $14.1 million, respectively. Factors contributing to the increased operating expenses in the three and six months ended June 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 six months ended June 30, 2025 and 2024, together with the dollar change and percentage change in those categories (dollars in thousands): Clinical and non-clinical trial expenses increased $1.6 million and $1.5 million for the three and six months ended June 30, 2025, respectively, compared to the three and six months ended June 30, 2024, due to increases in spend related to our (Z)-endoxifen trials, including drug development costs. The increases in R&D compensation expenses of $0.2 million and $0.4 million for the three and six months ended June 30, 2025, respectively, compared to the three and six months ended June 30, 2024, were due to increases in headcount. The increases in R&D professional fees and other of $0.2 million and $0.5 million for the three and six months ended June 30, 2025, respectively, compared to the three and six months ended June 30, 2024, were primarily attributable to higher consulting fees in the 2025 periods related to our (Z)-endoxifen program. General and Administrative (G&A) Expenses. The following table provides a breakdown of major categories within G&A expenses for the three and six months ended June 30, 2025 and 2024, together with the dollar change and percentage change in those categories (dollars in thousands): The increases in G&A compensation expenses of $0.5 million and $0.7 million for the three and six months ended June 30, 2025, respectively, compared to the three and six months ended June 30, 2024, were primarily due to increases in non-cash stock-based compensation expense of $0.4 million and $0.5 million, respectively. The decreases in G&A professional fees and other of $0.5 million for the three and six months ended June 30, 2025, compared to the three and six months ended June 30, 2024, were due to decreases in legal fees of $0.3 million and $0.2 million, respectively, related to higher patent-related activity as well as other legal matters in the prior year periods and decreases in investor relations costs of $0.1 million and $0.3 million, respectively, due to changes in the timing of investor outreach programs. Interest Income. Interest income was $0.6 million and $1.4 million for the three and six months ended June 30, 2025, respectively, a decrease of $0.5 million and $0.8 million from interest income of $1.1 million and $2.2 million for the three and six months ended June 30, 2024, respectively. The decreases were due to decreases in the average balance invested in our money market account. About (Z)-Endoxifen (Z)-endoxifen is a highly potent Selective Estrogen Receptor Modulator (SERM) with demonstrated ability to inhibit—and potentially degrade—estrogen receptors. It has shown activity even in tumors that have developed resistance to other endocrine therapies. Beyond its anti-estrogenic properties, (Z)-endoxifen also targets protein kinase C beta 1 (PKCβ1), an oncogenic signaling protein, at clinically achievable blood levels. Importantly, (Z)-endoxifen seems to deliver comparable or superior bone-protective effects relative to tamoxifen. Atossa is developing a proprietary enteric oral formulation of (Z)-endoxifen that bypasses stomach acid, which would otherwise convert the active (Z)-isomer to its inactive (E)-form. We believe this innovation allows for optimal bioavailability and therapeutic integrity. Clinical studies have shown Atossa's (Z)-endoxifen to be well tolerated in both healthy women and those with breast cancer. In over 700 subjects (healthy volunteers and breast cancer patients), doses up to 360 mg/day have been administered with no maximum tolerated dose (MTD) identified, supporting continued dose-ranging exploration. Atossa is prioritizing the development of (Z)-endoxifen for the treatment of metastatic breast cancer, where novel therapeutic options are urgently needed. The compound is currently being evaluated in three Phase 2 trials: one in women with ductal carcinoma in situ (DCIS) and two in women with ER+/HER2- breast cancer. Atossa's (Z)-endoxifen program is supported by a growing global intellectual property portfolio, including three recently issued U.S. patents and numerous pending applications worldwide. About Atossa Therapeutics Atossa Therapeutics, Inc. (Nasdaq: ATOS) is a clinical-stage biopharmaceutical company dedicated to transforming breast cancer treatment through innovative science and patient-focused solutions. The Company's lead product candidate, (Z)-endoxifen, is a highly potent SERM designed for use across the breast cancer spectrum, including prevention, neoadjuvant, adjuvant, and metastatic settings. Atossa is committed to advancing its robust clinical research programs to improve patient outcomes while creating sustainable value for shareholders. For more information, visit atossatherapeutics.com. FORWARD LOOKING STATEMENTS This press release contains certain information that may constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. We may identify these forward-looking statements by the use of words such as "expect," "potential," "continue," "may," "will," "should," "could," "would," "seek," "intend," "plan," "estimate," "anticipate," "believe," "design," "predict," "future," or other comparable words. All statements made in this press release that are not statements of historical fact, including statements regarding the Company's development strategy and related milestones, data related to the (Z)-endoxifen program, the safety, tolerability and efficacy of (Z)-endoxifen, the potential of (Z)-endoxifen as a breast cancer prevention and treatment agent, the potential indications that the Company may pursue for (Z)-endoxifen, the potential for (Z)-endoxifen to receive regulatory approval, including the potential IND submission and related timing, benefits of the Company's strategy of pursuing a metastatic indication for (Z)-endoxifen, the expected design and enrollment of trials and timing of data and related publications, the Company's progress across its pipeline, the strength of the Company's patent portfolio and expectations regarding related litigation, and the potential market and growth opportunities for the Company, are forward-looking statements. Forward-looking statements in this press release are subject to risks and uncertainties that may cause actual results, outcomes, or the timing of actual results or outcomes, to differ materially from those projected or anticipated, including risks and uncertainties associated with: our ability to obtain patent coverage for our product candidates; macroeconomic conditions and increasing geopolitical instability; the expected timing of releasing data; any variation between interim or preliminary and final clinical results or analysis; actions and inactions by the FDA and foreign regulatory bodies; the outcome or timing of regulatory approvals needed by Atossa, including those needed to continue our planned (Z)-endoxifen trials; our ability to satisfy regulatory requirements; our ability to regain compliance or maintain compliance with the continued listing requirements of the Nasdaq Stock Market; our ability to successfully develop and commercialize new therapeutics; the success, costs and timing of our development activities, including our ability to successfully initiate or complete our clinical trials, including our (Z)-endoxifen trials; our anticipated rate of patient enrollment; our ability to contract with third-parties and their ability to perform adequately; our estimates on the size and characteristics of our potential markets; our ability to successfully defend litigation and other similar complaints and to establish and maintain intellectual property rights covering our products; whether we can successfully complete our clinical trial of oral (Z)-endoxifen in women with mammographic breast density and our trials of (Z)-endoxifen in women with breast cancer, and whether the studies will meet their objectives; our expectations as to future financial performance, expense levels and capital sources, including our ability to raise capital; our ability to attract and retain key personnel; our anticipated working capital needs and expectations around the sufficiency of our cash reserves; and other risks and uncertainties detailed from time to time in Atossa's filings with the Securities and Exchange Commission, including without limitation its Annual Reports on Form 10-K and Quarterly Reports on 10-Q. Forward-looking statements are presented as of the date of this press release. Except as required by law, we do not intend to update any forward-looking statements, whether as a result of new information, future events or circumstances or otherwise. View original content to download multimedia:https://www.prnewswire.com/news-releases/atossa-therapeutics-announces-second-quarter-2025-financial-results-and-provides-a-corporate-update-302527683.html SOURCE Atossa Therapeutics Inc

Feasibility endpoint achieved; rapid Ki‑67 suppression and substantial MRI‑confirmed tumor shrinkage observed with favorable safety profile SEATTLE, May 14, 2025 /PRNewswire/ -- Atossa Therapeutics, Inc. (Nasdaq: ATOS) ("Atossa" or the "Company"), a clinical-stage biopharmaceutical company developing innovative medicines for breast cancer, today reported full results from the Phase 2 Endocrine Optimization Pilot (EOP) sub‑study within the I‑SPY 2 TRIAL evaluating low‑dose oral (Z)‑endoxifen (10 mg daily) as a neoadjuvant treatment in 20 women with stage II/III estrogen‑receptor–positive (ER+), HER2‑negative breast cancer. Key Findings: Primary feasibility goal surpassed – 95 percent of participants (19/20) completed at least 75 percent of planned dosing, far exceeding the predefined 75 percent threshold. Early anti‑proliferative activity – Median Ki‑67 fell from 10.5 percent at baseline to 5 percent by Week 3 (prior to ovarian suppression); 65 percent of patients achieved Ki‑67 ≤ 10 percent at that time point, and suppression was maintained at surgery. Robust imaging response – Median functional tumor volume (FTV) measurement (performed at baseline, week 3, week 12, and at surgery) decreased 77.7 percent (range 9.0 cc → 1.2 cc) from baseline to surgery, and the longest tumor diameter from baseline to preoperative MRI was reduced by 36.8 percent. Well‑tolerated safety profile – Adverse events were predominantly Grade 1; vasomotor symptoms (hot flushes) and fatigue were most common. Only three Grade 3 events (two skin infections, one post‑procedural infection) occurred in a single patient and were deemed unrelated to study drug; no Grade 4 or Grade 5 events were reported. Pathologic Findings:No participants achieved a pathologic complete response (pCR), and residual cancer burden (RCB) classes skewed toward RCB‑II/III, indicating moderate to extensive residual disease. This result was anticipated based on earlier window‑of‑opportunity (neoadjuvant) studies that showed significant pathologic clearance typically requires higher systemic exposures to (Z)-endoxifen (> 500 ng/mL) to enable inhibition of PKCβ1 in addition to ERα. The 10 mg dose in this pilot was intentionally selected to establish tolerability and early biologic activity in the endocrine‑naïve setting; therefore, limited pCR rates at this dose are consistent with prior dose–response observations. "These results show that even at a low capsule strength (Z)‑endoxifen is bioactive, producing rapid Ki‑67 suppression and meaningful tumor shrinkage, while remaining highly tolerable. The study strengthens our scientific hypothesis that dual targeting of ERα and PKCβ1 is key to inducing a pathological response," said Steven Quay, M.D., Ph.D., President and Chief Executive Officer of Atossa. "Importantly, it paves the way for our ongoing I‑SPY 2 cohorts evaluating higher, potentially PKCβ1‑engaging doses of (Z)‑endoxifen alone and in combination with the CDK4/6 inhibitor abemaciclib, where we aim to translate early biomarker gains into deeper pathologic responses." Atossa is actively enrolling participants into an additional I‑SPY 2 cohort testing (Z)‑endoxifen at a 40 mg daily dose and in combination with abemaciclib, with and without ovarian function suppression. Top‑line data from these arms are expected beginning in 2026. About (Z)-Endoxifen(Z)-endoxifen is a highly potent Selective Estrogen Receptor Modulator (SERM) with demonstrated ability to inhibit—and potentially degrade—estrogen receptors. It has shown activity even in tumors that have developed resistance to other endocrine therapies. Beyond its anti-estrogenic properties, (Z)-endoxifen also targets protein kinase C beta 1 (PKCβ1), an oncogenic signaling protein, at clinically achievable blood levels. Importantly, (Z)-endoxifen seems to deliver comparable or superior bone-protective effects relative to tamoxifen, while exhibiting minimal or no endometrial proliferative activity—addressing key limitations of current standard-of-care therapies. Atossa is developing a proprietary oral formulation of (Z)-endoxifen that is enteric-coated to bypass stomach acid, which would otherwise convert the active (Z)-isomer to its inactive (E)-form. This innovation ensures optimal bioavailability and therapeutic integrity. Clinical studies have shown Atossa's (Z)-endoxifen to be well tolerated in both healthy women and those with breast cancer. Atossa is prioritizing the development of (Z)-endoxifen for the treatment of metastatic breast cancer, where novel therapeutic options are urgently needed. The compound is currently being evaluated in three Phase 2 trials: one in women with ductal carcinoma in situ (DCIS) and two in women with ER+/HER2- breast cancer, including the EVANGELINE trial and the combination I-SPY study. Atossa's (Z)-endoxifen program is supported by a growing global intellectual property portfolio, including three recently issued U.S. patents and numerous pending applications worldwide. About Atossa TherapeuticsAtossa Therapeutics, Inc. (Nasdaq: ATOS) is a clinical-stage biopharmaceutical company dedicated to transforming breast cancer treatment through innovative science and patient-focused solutions. The company's lead product candidate, (Z)-endoxifen, is a highly potent SERM designed for use across the breast cancer spectrum, including prevention, neoadjuvant, adjuvant, and metastatic settings. Atossa is committed to advancing its robust clinical research programs to improve patient outcomes while creating sustainable value for shareholders. For more information, visit atossatherapeutics.com. FORWARD LOOKING STATEMENTSThis press release contains certain information that may constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. We may identify these forward-looking statements by the use of words such as "expect," "potential," "continue," "may," "will," "should," "could," "would," "seek," "intend," "plan," "estimate," "anticipate," "believe," "design," "predict," "future," or other comparable words. All statements made in this press release that are not statements of historical fact, including statements regarding data related to the (Z)-endoxifen program, the safety, tolerability and efficacy of (Z)-endoxifen, the potential of (Z)-endoxifen as a breast cancer prevention and treatment agent, the potential indications that the Company may pursue for (Z)-endoxifen, the potential for (Z)-endoxifen to receive regulatory approval, benefits of the Company's strategy of pursuing a metastatic indication for (Z)-endoxifen, the expected design and enrollment of trials and timing of data and related publications, and the potential market and growth opportunities for the Company, are forward-looking statements. Forward-looking statements in this press release are subject to risks and uncertainties that may cause actual results, outcomes, or the timing of actual results or outcomes, to differ materially from those projected or anticipated, including risks and uncertainties associated with: our ability to obtain patent coverage for our product candidates; macroeconomic conditions and increasing geopolitical instability; the expected timing of releasing data; any variation between interim or preliminary and final clinical results or analysis; actions and inactions by the FDA and foreign regulatory bodies; the outcome or timing of regulatory approvals needed by Atossa, including those needed to continue our planned (Z)-endoxifen trials; our ability to satisfy regulatory requirements; our ability to regain compliance or maintain compliance with the continued listing requirements of the Nasdaq Stock Market; our ability to successfully develop and commercialize new therapeutics; the success, costs and timing of our development activities, including our ability to successfully initiate or complete our clinical trials, including our (Z)-endoxifen trials; our anticipated rate of patient enrollment; our ability to contract with third-parties and their ability to perform adequately; our estimates on the size and characteristics of our potential markets; our ability to successfully defend litigation and other similar complaints and to establish and maintain intellectual property rights covering our products; whether we can successfully complete our clinical trial of oral (Z)-endoxifen in women with mammographic breast density and our trials of (Z)-endoxifen in women with breast cancer, and whether the studies will meet their objectives; our expectations as to future financial performance, expense levels and capital sources, including our ability to raise capital; our ability to attract and retain key personnel; our anticipated working capital needs and expectations around the sufficiency of our cash reserves; and other risks and uncertainties detailed from time to time in Atossa's filings with the Securities and Exchange Commission, including without limitation its Annual Reports on Form 10-K and Quarterly Reports on 10-Q. Forward-looking statements are presented as of the date of this press release. Except as required by law, we do not intend to update any forward-looking statements, whether as a result of new information, future events or circumstances or otherwise. View original content to download multimedia:https://www.prnewswire.com/news-releases/atossa-therapeutics-announces-full-results-from-ispy-2-endocrineoptimization-substudy-evaluating-lowdose-zendoxifen-302455086.html SOURCE Atossa Therapeutics Inc

Announced strategic plan to advance (Z)-endoxifen for metastatic breast cancer indication Enhanced (Z)-endoxifen intellectual property portfolio with three new U.S. patents, expanding IP portfolio to more than 200 patent claims related to (Z)-endoxifen Ended first quarter 2025 with $65.1 million in cash and cash equivalents and no debt SEATTLE, May 13, 2025 /PRNewswire/ -- Atossa Therapeutics, Inc. (Nasdaq: ATOS) (Atossa or the Company), a clinical-stage biopharmaceutical company developing innovative medicines for breast cancer, today announced its financial results for the first quarter ended March 31, 2025 and provided an update on recent company developments. First Quarter 2025 Highlights: Announced Strategic Decision to Pursue Metastatic Breast Cancer Indication: Atossa announced plans to target metastatic breast cancer as its lead program for (Z)-endoxifen. The decision reflects its commitment to addressing the persistent unmet medical need in metastatic breast cancer and the potential for a more streamlined regulatory pathway to deliver (Z)-endoxifen to these patients. Current treatment options for metastatic breast cancer often provide limited durability of response and substantial side effects. In previous clinical trials, (Z)-endoxifen has been shown to be well-tolerated as a selective estrogen receptor modulator (SERM), which Atossa believes supports its potential to fill this critical gap in treatment. Significantly Strengthened (Z)-endoxifen Patent Portfolio with Three New U.S. Patents: Atossa continued to bolster the intellectual property portfolio of (Z)-endoxifen with the grant of three new U.S. patents covering 31 claims directed at: sustained release compositions of (Z)-endoxifen (U.S. Patent No. 12,201,591); enteric oral formulations of (Z)-endoxifen and salts thereof as well as their use in treating hormone-dependent breast and reproductive tract disorders (U.S. Patent No. 12,275,684); and 58 claims covering (Z)-endoxifen formulations, including various levels of purity and stability as well as methods of using those formulations (U.S. Patent No. 12,281,056). Atossa's robust patent portfolio now encompasses more than 200 patent claims related to (Z)-endoxifen formulations and their clinical applications. "Our focus remains firmly on advancing (Z)-endoxifen as a next-generation therapy for breast cancer patients across the full spectrum of care—including a strategic emphasis on metastatic breast cancer, where therapeutic innovation is urgently needed," said Steven Quay, M.D., Ph.D., President and Chief Executive Officer of Atossa. "Across multiple clinical trials involving hundreds of patients, (Z)-endoxifen has consistently demonstrated strong tolerability and therapeutic versatility, which we believe shows its potential as a therapy for breast cancer from early-stage disease to more advanced stages. We are committed to unlocking the full potential of (Z)-endoxifen for patients while delivering value to our shareholders. A cornerstone of this strategy is the robust intellectual property portfolio we are building in an effort to protect our programs globally. As we look ahead to the remainder of 2025 and beyond, we are energized by the many opportunities to position (Z)-endoxifen as a potentially safer, more effective endocrine therapy for breast cancer patients worldwide." Comparison of Three Months Ended March 31, 2025 and 2024 Revenue and Cost of Revenue. For the three months ended March 31, 2025 and 2024, we had no source of revenue and no associated cost of revenue. Operating Expenses. Total operating expenses were $7.4 million for the three months ended March 31, 2025, which was an increase of $0.4 million, from the three months ended March 31, 2024 of $7.0 million. Factors contributing to the increased operating expenses in the three months ended March 31, 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 months ended March 31, 2025 and 2024, together with the dollar change and percentage change in those categories (dollars in thousands): Clinical and pre-clinical trial expenses decreased $0.1 million for the three months ended March 31, 2025, compared to the three months ended March 31, 2024, due to a slight decrease in spend related to our (Z)-endoxifen trials, including drug development costs. The increase in R&D compensation expenses of $0.3 million for the three months ended March 31, 2025, compared to the three months ended March 31, 2024 was due to an increase in headcount. The increase in R&D professional fees and other of $0.3 million was due to an increase in spending on regulatory consulting services. General and Administrative (G&A) Expenses. The following table provides a breakdown of major categories within G&A expenses for the three months ended March 31, 2025 and 2024, together with the dollar change and percentage change in those categories (dollars in thousands): The increase in G&A compensation expenses of $0.1 million for the three months ended March 31, 2025, compared to the three months ended March 31, 2024 was due to an increase in headcount quarter over quarter. Interest Income. Interest income was $0.7 million for the three months ended March 31, 2025, a decrease of $0.4 million from interest income of $1.1 million for the three months ended March 31, 2024. The decrease was due to a decrease in the balance in our money market account. About (Z)-Endoxifen(Z)-endoxifen is a highly potent SERM with demonstrated ability to inhibit—and potentially degrade—estrogen receptors. It has shown activity even in tumors that have developed resistance to other endocrine therapies. Beyond its anti-estrogenic properties, (Z)-endoxifen also targets protein kinase C beta 1 (PKCβ1), an oncogenic signaling protein, at clinically achievable blood levels. Importantly, (Z)-endoxifen seems to deliver comparable or superior bone-protective effects relative to tamoxifen, while exhibiting minimal or no endometrial proliferative activity—which we believe addresses key limitations of current standard-of-care therapies. Atossa is developing a proprietary oral formulation of (Z)-endoxifen that is enteric-coated to bypass stomach acid, which would otherwise convert the active (Z)-isomer to its inactive (E)-form. We believe this innovation allows for optimal bioavailability and therapeutic integrity. Clinical studies have shown Atossa's (Z)-endoxifen to be well tolerated in both healthy women and those with breast cancer. Atossa is prioritizing the development of (Z)-endoxifen for the treatment of metastatic breast cancer, where novel therapeutic options are urgently needed. The compound is currently being evaluated in three Phase 2 trials: one in women with ductal carcinoma in situ (DCIS) and two in women with estrogen receptor positive (ER+) / human epidermal growth factor receptor 2 negative (HER2-) breast cancer, including the EVANGELINE study and an I-SPY study. Atossa's (Z)-endoxifen program is supported by a growing global intellectual property portfolio, including three recently issued U.S. patents and numerous pending applications worldwide. About Atossa TherapeuticsAtossa Therapeutics, Inc. (Nasdaq: ATOS) is a clinical-stage biopharmaceutical company dedicated to transforming breast cancer treatment through innovative science and patient-focused solutions. The company's lead product candidate, (Z)-endoxifen, is a highly potent SERM designed for use across the breast cancer spectrum, including prevention, neoadjuvant, adjuvant, and metastatic settings. Atossa is committed to advancing its robust clinical research programs to improve patient outcomes while creating sustainable value for shareholders. For more information, visit atossatherapeutics.com. FORWARD LOOKING STATEMENTSThis press release contains certain information that may constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. We may identify these forward-looking statements by the use of words such as "expect," "potential," "continue," "may," "will," "should," "could," "would," "seek," "intend," "plan," "estimate," "anticipate," "believe," "design," "predict," "future," or other comparable words. All statements made in this press release that are not statements of historical fact, including statements regarding data related to the (Z)-endoxifen program, the safety, tolerability and efficacy of (Z)-endoxifen, the potential of (Z)-endoxifen as a breast cancer prevention and treatment agent, the potential indications that the Company may pursue for (Z)-endoxifen, the potential for (Z)-endoxifen to receive regulatory approval, benefits of the Company's strategy of pursuing a metastatic indication for (Z)-endoxifen, the expected design and enrollment of trials and timing of data and related publications, and the potential market and growth opportunities for the Company, are forward-looking statements. Forward-looking statements in this press release are subject to risks and uncertainties that may cause actual results, outcomes, or the timing of actual results or outcomes, to differ materially from those projected or anticipated, including risks and uncertainties associated with: our ability to obtain patent coverage for our product candidates; macroeconomic conditions and increasing geopolitical instability; the expected timing of releasing data; any variation between interim or preliminary and final clinical results or analysis; actions and inactions by the FDA and foreign regulatory bodies; the outcome or timing of regulatory approvals needed by Atossa, including those needed to continue our planned (Z)-endoxifen trials; our ability to satisfy regulatory requirements; our ability to regain compliance or maintain compliance with the continued listing requirements of the Nasdaq Stock Market; our ability to successfully develop and commercialize new therapeutics; the success, costs and timing of our development activities, including our ability to successfully initiate or complete our clinical trials, including our (Z)-endoxifen trials; our anticipated rate of patient enrollment; our ability to contract with third-parties and their ability to perform adequately; our estimates on the size and characteristics of our potential markets; our ability to successfully defend litigation and other similar complaints and to establish and maintain intellectual property rights covering our products; whether we can successfully complete our clinical trial of oral (Z)-endoxifen in women with mammographic breast density and our trials of (Z)-endoxifen in women with breast cancer, and whether the studies will meet their objectives; our expectations as to future financial performance, expense levels and capital sources, including our ability to raise capital; our ability to attract and retain key personnel; our anticipated working capital needs and expectations around the sufficiency of our cash reserves; and other risks and uncertainties detailed from time to time in Atossa's filings with the Securities and Exchange Commission, including without limitation its Annual Reports on Form 10-K and Quarterly Reports on 10-Q. Forward-looking statements are presented as of the date of this press release. Except as required by law, we do not intend to update any forward-looking statements, whether as a result of new information, future events or circumstances or otherwise.     View original content to download multimedia:https://www.prnewswire.com/news-releases/atossa-therapeutics-announces-first-quarter-2025-financial-results-and-provides-a-corporate-update-302453446.html SOURCE Atossa Therapeutics Inc

Ended 2024 with $71.1 million of cash and cash equivalents and no debt Conference Call and Webcast Scheduled for Tuesday, March 25, 2025, at 8:30 a.m. Eastern Time SEATTLE, March 25, 2025 (GLOBE NEWSWIRE) -- Atossa Therapeutics, Inc. (Nasdaq: ATOS) (“Atossa” or the “Company”), a clinical-stage biopharmaceutical company developing innovative medicines for breast cancer, today announced its financial results for the full year ended December 31, 2024 and provided an update on recent company developments. Fourth Quarter and Early 2025 Highlights Strategic Decision to Pursue Metastatic Breast Cancer Indication: Atossa plans to advance its lead program, (Z)-endoxifen, to target metastatic breast cancer. The Company believes this approach may offer a more streamlined regulatory pathway to deliver (Z)-endoxifen to patients with urgent unmet medical needs, as the current treatment options for metastatic breast cancer often provides limited durability of response and substantial side effects. (Z)-endoxifen—a potent and well-tolerated selective estrogen receptor modulator (SERM)—has shown encouraging signs in previous clinical trials, which Atossa believes supports its potential to fill this critical gap in treatment. Atossa also intends to continue engagement with the U.S. Food and Drug Administration (FDA) to advance additional indications, including breast cancer prevention and neoadjuvant therapy, which typically require larger and longer clinical trials. Tolerability and Pharmacokinetic Data from Phase 2 Evangeline Trial: Atossa presented three posters at the San Antonio Breast Cancer Symposium (SABCS) highlighting pharmacokinetic (PK) and tolerability data from the Phase 2 EVANGELINE trial. This randomized, non-inferiority study evaluates (Z)-endoxifen in premenopausal women with primary ER+/HER2- breast cancer as a neoadjuvant treatment. Substantial tumor suppression was observed across all dosing levels, with or without ovarian function suppression (OFS or goserelin). The 4-week Ki-67 ≤ 10 percent response rate was generally above 85 percent across dose levels, with or without the presence of OFS. Overall, (Z)-endoxifen was well tolerated and target tissue steady state concentration (Css) levels were achieved without significant Grade 3 or 4 toxicities. Given the gynecologic events that were previously reported in the 80 mg groups, the study is expected to continue under an amended protocol as a randomized trial that compares (Z)-endoxifen 40 mg per day with OFS to exemestane plus OFS, using the 4-week Ki-67 reduction as the primary endpoint. Additionally, the trial is expected to include a single arm cohort with a 40 mg (Z)-endoxifen monotherapy neoadjuvant treatment, using a 24-week Ki-67 endpoint. Full Results from Phase 2 KARISMA-Endoxifen Study: Additional SABCS data showcased the potential of low-dose (Z)-endoxifen to significantly reduce mammographic breast density (MBD). In the trial, a 1 mg dose reduced MBD by 17.3 percentage points (p<0.01), while a 2 mg dose achieved a 23.5 percentage-point reduction (p<0.01), compared to just 0.27 percentage points in the placebo arm, which we believe highlights the effectiveness of the lower dose in achieving significant reductions. Importantly, no significant differences in adverse events of special interest were observed between the 1 mg dose and the placebo. The 2 mg dose was associated with higher rates of hot flashes, night sweats and vaginal discharge compared to the placebo group. We believe these findings further support the therapy’s favorable safety and efficacy profile. “Metastatic breast cancer remains an area of critical unmet need, where improved therapies are urgently required,” said Steven Quay, M.D., Ph.D., President and Chief Executive Officer of Atossa. “(Z)-endoxifen has demonstrated promising anti-estrogenic and anti-tumor effects alongside a favorable tolerability profile, which we believe positions it as a potential next-generation therapy. We believe that pursuing an initial approval in metastatic breast cancer could offer a more efficient regulatory pathway, potentially enabling us to make (Z)-endoxifen available sooner to the patients who need it most. We also believe this strategy further supports our ability to expand the broader potential of (Z)-endoxifen to address multiple stages of breast cancer, from reducing tumor growth to preventing recurrence after successful treatment.” Conference Call Information:The webcast will be available at the investor relations section of the Company's website at atossatherapeutics.com. Alternatively, to access the conference call by telephone, U.S.-based callers should dial 1-800-836-8184 and international listeners should dial 1-646-357-8785. All listeners should provide the operator with the conference call name "Atossa Therapeutics Business Update" to join. Following the conclusion of the conference call, a replay will be available for 30 days on the investor relations section of the Company's website at atossatherapeutics.com. Comparison of Years Ended December 31, 2024 and 2023 Operating Expenses. Total operating expenses were $27.6 million for the year ended December 31, 2024, which was a decrease of $3.8 million, from the year ended December 31, 2023 of $31.4 million. Factors contributing to the decreased operating expenses in the year ended December 31, 2024 are explained below. Research & Development (R&D) Expenses. The following table provides a breakdown of major categories within R&D expenses for the years ended December 31, 2024 and 2023, together with the dollar change in those categories (dollars in thousands): General and Administrative (G&A) Expenses. The following table provides a breakdown of major categories within G&A expenses for the years ended December 31, 2024 and 2023, together with the dollar change in those categories (dollars in thousands): Interest Income. Interest income of $4.1 million for the year ended December 31, 2024 represented a decrease of $0.2 million compared to the prior year and was primarily due to a decrease in funds invested in the money market account. Impairment Charge on Investment in Equity Securities. For the years ended December 31, 2024 and 2023, we wrote down our investment in equity securities by $1.7 million and $3.0 million, respectively, due to impairment of our investment in Dynamic Cell Therapies, Inc. About (Z)-Endoxifen(Z)-endoxifen is one of the most potent Selective Estrogen Receptor Modulator (SERM) for estrogen receptor inhibition and may cause estrogen receptor degradation. It has also been shown to have efficacy in the setting of patients with tumor resistance to other hormonal treatments. In addition to its potent anti-estrogen effects, (Z)-endoxifen has been shown to target PKCβ1, a known oncogenic protein, at clinically attainable blood concentrations. Finally, (Z)-endoxifen appears to deliver similar or even greater bone agonistic effects while resulting in little or no endometrial proliferative effects compared with standard treatments, like tamoxifen. Atossa is developing a proprietary oral formulation of (Z)-endoxifen that is encapsulated to bypass the stomach, as acidic conditions in the stomach convert a significant proportion of (Z)-endoxifen to the inactive (E)-endoxifen. Atossa’s (Z)-endoxifen has been shown to be well tolerated in clinical studies of women with and without breast cancer. (Z)-endoxifen is currently being studied in four Phase 2 trials: one in women diagnosed with ductal carcinoma in situ, and three other studies including the EVANGELINE study and two I-SPY studies in women with ER+/HER2- breast cancer. Atossa’s (Z)-endoxifen is protected by three issued U.S. patents and numerous pending patent applications. About Atossa TherapeuticsAtossa Therapeutics, Inc. (Nasdaq: ATOS) is a clinical-stage biopharmaceutical company dedicated to transforming breast cancer treatment through innovative science and patient-focused solutions. The company’s lead product candidate, (Z)-endoxifen, is a highly potent SERM designed for use across the breast cancer spectrum, including prevention, neoadjuvant, adjuvant, and metastatic settings. Atossa is committed to advancing its robust clinical research programs to improve patient outcomes while creating sustainable value for shareholders. For more information, visit atossatherapeutics.com. FORWARD LOOKING STATEMENTSThis press release contains certain information that may constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. We may identify these forward-looking statements by the use of words such as “expect,” “potential,” “continue,” “may,” “will,” “should,” “could,” “would,” “seek,” “intend,” “plan,” “estimate,” “anticipate,” “believe,” “design,” “predict,” “future,” or other comparable words. All statements made in this press release that are not statements of historical fact, including statements regarding data related to the (Z)-endoxifen program, the safety, tolerability and efficacy of (Z)-endoxifen, the potential of (Z)-endoxifen as a breast cancer prevention and treatment agent, the potential indications that the Company may pursue for (Z)-endoxifen, the potential for (Z)-endoxifen to receive regulatory approval, benefits of the Company’s strategy of pursuing a metastatic indication for (Z)-endoxifen, the expected design and enrollment of trials and timing of data and related publications, and the potential market and growth opportunities for the Company, are forward-looking statements. Forward-looking statements in this press release are subject to risks and uncertainties that may cause actual results, outcomes, or the timing of actual results or outcomes, to differ materially from those projected or anticipated, including risks and uncertainties associated with: our ability to obtain patent coverage for our product candidates; macroeconomic conditions and increasing geopolitical instability; the expected timing of releasing data; any variation between interim or preliminary and final clinical results or analysis; actions and inactions by the FDA and foreign regulatory bodies; the outcome or timing of regulatory approvals needed by Atossa, including those needed to continue our planned (Z)-endoxifen trials; our ability to satisfy regulatory requirements; our ability to regain compliance or maintain compliance with the continued listing requirements of the Nasdaq Stock Market; our ability to successfully develop and commercialize new therapeutics; the success, costs and timing of our development activities, including our ability to successfully initiate or complete our clinical trials, including our (Z)-endoxifen trials; our anticipated rate of patient enrollment; our ability to contract with third-parties and their ability to perform adequately; our estimates on the size and characteristics of our potential markets; our ability to successfully defend litigation and other similar complaints and to establish and maintain intellectual property rights covering our products; whether we can successfully complete our clinical trial of oral (Z)-endoxifen in women with mammographic breast density and our trials of (Z)-endoxifen in women with breast cancer, and whether the studies will meet their objectives; our expectations as to future financial performance, expense levels and capital sources, including our ability to raise capital; our ability to attract and retain key personnel; our anticipated working capital needs and expectations around the sufficiency of our cash reserves; and other risks and uncertainties detailed from time to time in Atossa’s filings with the Securities and Exchange Commission, including without limitation its Annual Reports on Form 10-K and Quarterly Reports on 10-Q. Forward-looking statements are presented as of the date of this press release. Except as required by law, we do not intend to update any forward-looking statements, whether as a result of new information, future events or circumstances or otherwise. Contact: Michael Parks VP, Investor and Public [email protected]