ITEM 7. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

The following discussion of our financial condition and results of operations should be read in conjunction with the Consolidated Financial Statements and the related notes included elsewhere in this Annual Report. This discussion contains forward-looking statements, which are based on assumptions about the future of our business. Actual results, outcomes and the timing of results or outcomes could differ materially from those contained in the forward-looking statements. Please read "Note Regarding Forward-Looking Statements"included elsewhere in this Annual Report for additional information regarding forward-looking statements.

Company Overview

We are a clinical-stage biopharmaceutical company developing proprietary innovative medicines in areas of significant unmet medical need in oncology, with a focus on breast cancer and other breast conditions, as well as certain rare diseases. Our lead drug candidate is oral (Z)-endoxifen, a selective estrogen receptor modulator (SERM)/ selective estrogen receptor degrader (SERM/D) currently in Phase 2 clinical development. The Company is evaluating potential indications for (Z)-endoxifen based on its pharmacologic profile, including its potential for both reducing the risk of and for the treatment of breast cancer, as well as in other therapeutic areas.

We have been granted seven U.S. and 16 international patents covering our proprietary (Z)-endoxifen, and we have numerous applications pending in the U.S. and in other major countries. We expect to have patent protection covering our proprietary (Z)-endoxifen through at least November 17, 2038.

Our business strategy is to advance our programs through clinical studies, including with potential partners, and opportunistically add programs in areas of high unmet medical need through acquisition, minority investment, collaboration or internal development.

(Z) endoxifen. (Z)-endoxifen is the most active metabolite of Tamoxifen, a U.S. Food and Drug Administration (FDA) approved drug to treat and prevent breast cancer in high-risk women, and it is substantially more potent as an estrogen receptor antagonist than Tamoxifen and other approved SERMs. Unlike Tamoxifen, which requires metabolic activation through CYP2D6 and other liver enzymes, (Z)-endoxifen does not require first-pass metabolism to achieve therapeutic concentrations. As a result, its activity is not dependent on patient-specific metabolic variability.

(Z)-endoxifen is a small-molecule oral agent designed to directly inhibit estrogen receptor signaling, induce estrogen receptor degradation, and promote apoptosis in estrogen receptor positive (ER+) breast cancer cells. Preclinical and clinical data suggest that (Z)-endoxifen may inhibit clinically relevant ESR1 mutations associated with resistance to aromatase inhibitors and may also inhibit protein kinase C beta one (PKCβ1), resulting in downregulation of the AKT signaling pathway. We are evaluating (Z)-endoxifen across multiple settings within the ER+/human epidermal growth factor receptor 2 negative (HER2-) breast cancer treatment continuum, including neoadjuvant, adjuvant and breast density reduction indications.

In an ongoing neoadjuvant clinical study, (Z)-endoxifen has demonstrated early signs of anti-tumor activity. Reported results include one complete response and multiple partial responses, as well as substantial reductions in Ki-67 proliferation across dose levels. Tumor shrinkage was observed by MRI imaging, which is atypical for endocrine therapies that are generally cytostatic.

We are also supporting multiple collaborative and investigator-sponsored clinical studies evaluating (Z)-endoxifen in additional breast cancer settings. These studies are not fully funded by us and are intended to further characterize clinical activity, optimize endocrine therapy strategies, and inform future regulatory pathways.

Based on its mechanism of action, we are exploring the potential application of (Z)-endoxifen beyond breast cancer, including gynecological cancers, endocrine resistance driven by ESR1 mutations, as well as applications in other rare disease indications, including Duchenne Muscular Dystrophy (DMD), women carriers of DMD, and McCune-Albright Syndrome (MAS) in girls. In preclinical models of DMD, (Z)-endoxifen demonstrated muscle-protective, anti-inflammatory, and anti-fibrotic effects. We believe similar efficacy could potentially apply to women carriers of DMD. For MAS, we believe (Z)-endoxifen could potentially be an effective hormone blocker, significantly reducing the effects of early onset puberty in young girls. We have developed a proprietary manufacturing process for (Z)-endoxifen, including defined processes for the active pharmaceutical ingredient and drug product. The drug product is available in multiple dosage strengths and is supported by qualified suppliers and manufacturing redundancies.

Summary of Our Leading Programs

We are developing a proprietary form of (Z)-endoxifen which is administered orally for the potential treatment of high-risk breast cancer and the reduction of mammographic breast density (MBD). As part of this development, we are also evaluating the potential for (Z)-endoxifen to work in combination with other cancer treatment therapies for premenopausal and postmenopausal women with high-risk breast cancer.

In addition to oncology related indications, we believe (Z)-endoxifen has potentially broader utility as a therapeutic platform in serious and rare diseases, many of which have significant unmet medical need. There is growing scientific evidence supporting the

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potential role of estrogen signaling modulation in muscle preservation and inflammation associated with conditions, such as DMD and MAS, among others.

The following is a summary of the status of our major oncology and rare disease clinical development programs as of the date of this Annual Report:

Oncology/Breast Cancer

In support of our breast cancer risk reduction and treatment indications, we have completed four Phase 1 clinical studies (including a study in men) and two Phase 2 clinical studies with our proprietary (Z)-endoxifen (including oral and topical formulations). We have also completed significant pre-clinical development and have developed clinical manufacturing capabilities through qualified third parties.

Karisma Study

(Z)-endoxifen for Women with Mammographic Breast Density. MBD is an emerging public health issue. Almost half of the women in the world over the age of 40 have dense breasts, and there are currently no approved treatments to reduce breast density. Elevated breast density can make a mammogram more difficult to interpret because dense breast tissue and some abnormal breast changes, such as calcifications and tumors, appear as white areas in a mammogram. Women with the highest density are four to six times more likely to develop breast cancer in their lifetime and more likely to develop cancer between mammograms compared to those with low breast density. The latter are sometimes referred to as "interval cancers," which are often larger, more advanced, and more difficult to treat.

In December 2021, we commenced a Phase 2 study of our proprietary oral (Z)-endoxifen. The study, known as the Karisma-(Z)-endoxifen study, was a Phase 2, randomized, double-blind, placebo-controlled, dose-response study of our proprietary oral (Z)-endoxifen in healthy premenopausal women with measurable MBD. The primary objective of the study was to determine the dose-response relationship of daily (Z)-endoxifen on breast density reduction. Secondary endpoints assessed safety and tolerability. The study was conducted in Stockholm, Sweden and included approximately 240 participants who received daily doses of oral (Z)-endoxifen or placebo for six months after enrollment, randomized to one of three arms: placebo, 1 mg of (Z)-endoxifen, or 2 mgs of (Z)-endoxifen. The study also included an exploratory endpoint to assess twenty-four month durability of the breast density changes. Top line data for this study measuring both MBD reduction after six months of treatment and data regarding twenty-four month durability is expected in the first quarter of 2026.

The study fully enrolled in November 2023 and in September 2024, the primary objective measuring MBD after six months of treatment, was concluded. The data showed the potential of low-dose (Z)-endoxifen to significantly reduce MBD with a favorable safety profile.

The 1 mg dose of (Z)-endoxifen reduced MBD by 17.3% (p<0.01), while the 2 mg dose achieved a reduction of 23.5% (p<0.01), compared to a minimal change in the placebo group of 0.27%. Plasma concentrations for (Z)-endoxifen were measured at 4.8 ng/mL and 9.7 ng/mL for the 1 mg and 2 mg arms, respectively, demonstrating the effectiveness of the lower dose in achieving significant MBD reductions. Importantly, no significant differences in adverse events 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.

We expect to report top-line data from the Karisma (Z)-endoxifen study in the first half of 2026. Further development will depend on regulatory guidance, study outcomes, and available resources.

RECAST DCIS Study

Ductal Carcinoma in Situ (DCIS) is the presence of abnormal cells inside a milk duct in the breast. It rarely produces symptoms, or a breast lump one can feel, and is typically detected through screening mammography. In some cases, DCIS may become invasive and spread to other tissues, but there is no way of determining which lesions will remain stable without treatment and which will go on to become invasive. This uncertainty can result in aggressive and unnecessary treatment approaches that can have harmful side effects without significant benefit.

In October 2023, the Quantum Leap Healthcare Collaborative (the QLHC) announced the initiation of the Phase 2 DCIS: Re-Evaluating Conditions for Active Surveillance Suitability as Treatment (the RECAST) study. (Z)-endoxifen is being investigated as part of this platform trial, which offers women with DCIS six months of neoadjuvant treatment with the intent of determining their suitability for long-term active surveillance without surgery. Approximately 100 patients are expected to be treated with (Z)-endoxifen. The study incorporates both a neoadjuvant therapy phase, with patients at high risk for progression to invasive disease proceeding to surgery, followed by an extended surveillance phase for low-risk patients. Enrollment in this study is ongoing.

EVANGELINE Study

We are also developing (Z)-endoxifen to treat estrogen receptor positive (ER+) / human epidermal growth factor receptor 2 negative (HER2-) breast cancer in the neoadjuvant setting, which is the administration of a therapy before the main treatment, which is usually surgery. Although there are neoadjuvant treatments for breast cancers that are not ER+, there are few neoadjuvant treatments for ER+ breast cancer which comprises approximately 240,000 new cases or approximately 80% of all breast cancers each year.

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In October 2022, we received authorization from the FDA for our Investigational New Drug (IND) application for oral (Z)-endoxifen. The study, known as "EVANGELINE," is a Phase 2 randomized study designed to assess (Z)-endoxifen as neoadjuvant therapy in premenopausal women with primary ER+/HER2– breast cancer. As originally designed, the study was to consist of two parts: Part 1 was a Pharmacokinetic (PK) Run-In Cohort evaluating daily dosing of 40 mg and 80 mg to assess if a plasma steady state concentration (Css) of 500 to 1000 ng/mL, which is required for optimal PKC-β inhibition, could be achieved; and Part 2 was expected to compare the two treatment arms based on baseline Ki-67 levels, with the aim of evaluating the endocrine sensitive disease rate, pathologic complete response, and other key endpoints.

Data showed that none of the patients in the 40 mg cohort reached the target Css. However, in the 80 mg cohort, approximately 50% of patients receiving (Z)-endoxifen with goserelin and 38% of patients receiving (Z)-endoxifen alone attained the target plasma Css, with an average of 484 ng/mL. Importantly, tumor Css levels were found to be more than double the plasma levels, exceeding 500 ng/g in 90% of patients, and 85% of patients exhibited a 4-week Ki-67 response (≤10%), indicating substantial tumor suppression. (Z)-endoxifen was generally well tolerated, with no significant Grade 3 or 4 toxicities, although four gynecologic events (including one Grade 3 hemorrhagic ovarian cyst) were noted in the 80 mg group.

Based on preliminary results from the 40 mg and 80 mg cohorts, the EVANGELINE study design and treatment protocol were amended in 2025. The study design has been updated to a single-arm, open-label, Phase 2 in premenopausal women with ER+/HER2– breast cancer in the pre-surgical setting. The study includes two Cohorts: Cohort A (signal-seeking), a two-stage futility design assessing the Week-4 Ki-67 ≤10% rate to allow early stop if not promising, and Cohort B (estimation), assessing Week-24 objective response (RECIST 1.1, central review). The amended design will focus on objective, short-interval endpoints to inform development decisions efficiently while working to preserve patient safeguards.

The initial EVANGELINE study design included enrollment estimates for 214 patients and has been amended to reduce enrollment totals to 40-65 patients. Enrollment in this study is ongoing, and it is expected to be complete in the second quarter of 2026.

I-SPY 2 Endocrine Optimization Pilot Study

In March 2023, a second neoadjuvant Phase 2 trial investigating oral (Z)-endoxifen as a treatment for women diagnosed with locally advanced ER+/HER2- breast cancer was initiated. This trial is a study arm in the ongoing I‐SPY 2 Endocrine Optimization Pilot (I-SPY 2 EOP) which is a collaborative effort among academic investigators from major cancer research centers across the U.S., QLHC, the FDA, and the Foundation for the National Institutes of Health (FNIH) Cancer Biomarkers Consortium. This study included twenty women who received 10 mg of (Z)-endoxifen (monotherapy) orally once daily for six cycles (each cycle = 28 days) or up to 24 weeks prior to surgery.

For the monotherapy arm of I-SPY 2 EOP, enrollment was completed in January 2024 and 3-week preliminary data results were reported in October 2024. In May 2025, we reported updated results from this study which found that (i) 95% of participants (19/20 participants) completed at least 75% of planned dosing, (ii) median Ki-67 fell from 10.5% at baseline to 5% by Week 3, (iii) 65% of patients achieved Ki-67< 10% at Week 3 with suppression maintained at surgery, (iv) median functional tumor volume measurement (performed at baseline, Week 3, Week 12 and at surgery) decreased 77.7% from baseline to surgery, and (v) the longest tumor diameter in the participants from baseline to preoperative MRI was reduced by 36.8%. (Z)-endoxifen was well tolerated in this study with the most common side effects being relatively mild, consisting of hot flashes, insomnia, and fatigue. No dose reductions or discontinuations due to treatment related adverse events occurred during this study.

In April and June of 2024, we announced our participation in two new study arms of the I-SPY 2 EOP which were initiated to evaluate our proprietary (Z)-endoxifen in combination with two FDA approved drugs: 1) abemaciclib (VERZENIO®), a cyclin-dependent kinase (CDK) 4/6 inhibitor marketed by Eli Lilly and Company, and 2) elagolix (ORILISSA®), a prescription medicine used to treat moderate to severe pain associated with endometriosis marketed by AbbVie, Inc. Total enrollment across the combination therapy arms of this study is expected to be approximately 90 enrollees. Preliminary data has not been made available related to the ongoing combination therapy arms of I-SPY 2 EOP. Enrollment in the combination therapy arms of this nearly complete, and we expect to begin receiving data in the second half of 2026.

Rare Pediatric Disease and Orphan Designations

Duchenne Muscular Dystrophy

DMD is a serious and progressive neuromuscular disease that primarily affects boys, leading to loss of muscle function, loss of ambulation, and life-threatening heart and respiratory complications. We believe that (Z)-endoxifen’s direct estrogen-receptor modulation, PKC inhibition, and effects on key signaling pathways could be relevant in addressing various pathologies associated with DMD, including inflammation, fibrosis, and cardiomyopathy. Through its potential ability to upregulate utrophin, (Z)-endoxifen may help stabilize muscle health, including muscle growth, repair, and fibrosis. FDA engagement commenced in Q4 2025.

In December 2025 and early in 2026, we received two FDA designations for (Z)-endoxifen for the treatment of DMD: 1) Rare Pediatric Disease Designation and 2) Orphan Drug Designation. We believe these designations provide us with several potential strategic benefits, including incentives, such as a potential Priority Review Voucher (PRV) for future FDA applications, other

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regulatory support, and potential market exclusivity for a period of time. PRVs, which were recently reauthorized by legislation, could create significant value and could represent a meaningful source of non-dilutive value opportunities, either through use in another program or monetization through sale to third parties.

Women Carriers of DMD

(Z)-endoxifen has also shown potential relevance in symptomatic female Duchenne and Becker muscular dystrophy carriers, an under-recognized population in which a subset may experience skeletal-muscle symptoms or develop dilated cardiomyopathy in adult life. The work done in 2025, including our manuscript entitled, "(Z)-Endoxifen as a Modulator of Utrophin Pathways in Duchenne Muscular Dystrophy,” will continue to inform our hypotheses and potential clinical trial protocols in 2026. Additionally, we believe this condition meets the requirements of and could qualify for Orphan Drug Designation, and we intend to pursue this designation in the first half of 2026.

McCune-Albright Syndrome:

MAS is a rare, non-inherited genetic disorder caused by a postzygotic GNAS mutation, affecting bones, skin, and the endocrine system, with symptoms typically appearing in early childhood. In young girls (as early as 2 years old), early onset puberty can occur (Precocious Puberty) which can have a very significant effect on quality of life and limit growth. We believe that (Z)-endoxifen could prove to be an effective hormone blocker and potentially significantly reduce the effects of Precocious Puberty until young girls reach a more typical age for the onset of puberty and related developmental changes. Given the age of impacted girls and the relatively small size of this impacted population, we expect to seek both Rare Pediatric Disease and Orphan Drug designations for MAS in the first half of 2026.

Research and Development Phase

We are in the research and development phase and are not currently marketing any products. We do not anticipate generating revenue unless and until we develop and launch our pharmaceutical programs.

Commercial Lease Agreement

On September 22, 2025, we entered into an operating lease with 1448 NW Market Street Tenant LLC for additional office space in Seattle, Washington. We agreed to pay $3 thousand per month for 13 months commencing on November 1, 2025.

Reverse Stock Split

The Reverse Stock Split did not change the par value of the common stock or the authorized number of shares of common stock. Proportionate adjustments were made (i) in accordance with the terms of the Company’s equity plans, to the number of shares subject to outstanding equity awards, the per share exercise price, if any, with respect to those awards and the number of shares of common stock reserved for future issuance under such plans, and (ii) in accordance with the Certificate of Designation of Preferences, Rights and Limitation of the Series B Convertible Preferred Stock (Preferred Stock), to the conversion price of the Preferred Stock and the number of shares of common stock reserved for issuance pursuant to the Preferred Stock. All applicable common stock and per share amounts have been retrospectively restated to reflect the effect of the reverse stock split.

Critical Accounting Estimates

Our management's discussion and analysis of our financial condition and results of operations is based on our Consolidated Financial Statements, which have been prepared in accordance with accounting principles generally accepted in the United States (U.S. GAAP). The preparation of these Consolidated Financial Statements requires us to make estimates and judgments that affect the reported amounts of assets, liabilities and expenses. We base our estimates on our historical experience, known trends and events, and on various other factors that we believe to be reasonable under the circumstances, the results of which form the basis for making our judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Our actual results may differ from these estimates under different assumptions or conditions.

We believe that the following are the most critical accounting estimates used in the preparation of our Consolidated Financial Statements.

Research and Development Expenses

Research and Development (R&D) costs are generally expensed as incurred. R&D expenses include, for example, manufacturing expense for our drugs under development, expenses associated with preclinical studies, clinical trials and associated salaries, bonuses, stock-based compensation and benefits. R&D expenses also include an allocation of the CEO's salary and related

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benefits, including bonus and non-cash stock-based compensation expense, based on an estimate of his total hours spent on research and development activities.

We have entered into various research and development contracts with Contract Research Organizations (CROs), contract manufacturing organizations (CMOs) and other companies. The majority of our service providers invoice us monthly for services performed, however, payments under some of these contracts may be required in advance of the services being performed, for example when a contract requires an initial payment at the outset of the contract. Payments made in advance of performance of services are reflected in the Consolidated Balance Sheets as prepaid expenses.

Clinical Trial and Preclinical Study Accruals

We make estimates of our accrued expenses for clinical trial and preclinical study activities based on the facts and circumstances known to us at the time. These accruals are based upon estimates of costs incurred and fees that may be associated with services provided by clinical trial investigational sites and CROs, CMOs and for other clinical trial-related activities. In accruing for these services, we estimate the time period over which services will be performed and the level of effort to be expended in each period. If possible, we obtain information regarding unbilled services directly from these service providers. However, we may be required to estimate these services based on other information available to us by reviewing contracts, vendor agreements and through discussions with internal clinical and preclinical personnel and external service providers as to the progress or stage of completion of services and the agreed-upon fee to be paid for such services. If we underestimate or overestimate the activities or fees associated with a study or service at a given point in time, adjustments to research and development expenses may be necessary in future periods. Historically, our estimated accrued liabilities have approximated actual expense incurred. Subsequent changes in estimates may result in a material change in our accruals.

There may be instances in which payments made to our vendors exceed the level of services provided and result in a prepayment of the expense. In accruing service fees, we estimate the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, we adjust the accrual or prepaid expense accordingly.

Stock-Based Compensation

We measure all stock option awards granted to employees, non-employee directors and consultants based on the fair value on the date of grant, and we recognize compensation expense over the requisite service period, which is generally the vesting period of the award. The straight-line method of expense recognition is applied to all awards with service-only conditions. We account for forfeitures as they occur.

The fair value of each option grant is estimated using the Black-Scholes option-pricing model, which requires assumptions regarding the expected volatility of the price of our common stock, the expected life of the options, an expectation regarding future dividends on our common stock, an estimate of the appropriate risk-free interest rate and the expected term. Our expected common stock price volatility assumption is based upon the historic volatility of our stock price. The expected life for stock option grants is based on an average of the contractual term of the options of 10 years with the average vesting term of one to four years. The dividend yield assumption of zero is based upon the fact that we have never paid cash dividends and presently have no intention of paying cash dividends in the future. The risk-free interest rate is based upon prevailing short-term interest rates over the expected lives of the options.

While assumptions used to calculate and account for stock-based compensation awards represent management’s best estimates, these estimates involve inherent uncertainties and the application of management’s judgment.

Results of Operations

Comparison of Years Ended December 31, 2025 and 2024

Revenue and Cost of Revenue. For the years ended December 31, 2025 and 2024, we had no source of revenue and no associated cost of revenue.

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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):

Year Ended December 31, 2025 Year Ended December 31, 2024 Increase % Increase

Research and Development Expense

As (Z)-endoxifen is our only product candidate for which we currently incur R&D expense, we have not further disaggregated R&D expenses by product candidate:

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):

General and Administrative Expense

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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. Refer to Note 4 "Investment in Equity Securities" to the Consolidated Financial Statements for more information.

Income Taxes. We did not record an income tax expense or benefit for the years ended December 31, 2025 and 2024 due to uncertainty regarding utilization of our net operating loss carryforwards and our history of losses.

Liquidity and Capital Resources

On June 27, 2024, our stockholders approved an amendment to our Amended and Restated Certificate of Incorporation to increase the number of authorized shares of our common stock, par value $0.18 per share, from 175,000,000 to 350,000,000. As of December 31, 2025, we are authorized to issue 350,000,000 shares of common stock, par value $0.18 per share.

On November 19, 2024, we entered into an Open Market Sale AgreementSM with Jefferies LLC (the Prior ATM Facility), pursuant to which we were able to offer, from time to time, to sell, in an "at the market offering," shares of our common stock up to an aggregate offering price of up to $100.0 million. We did not make any sales under the Prior ATM Facility during the year ended December 31, 2025, and the Prior ATM Facility was cancelled on February 19, 2026.

On February 20, 2026, we entered into the At the Market Offering Agreement, dated February 20, 2026 (the Sales Agreement), with Rodman & Renshaw LLC. Pursuant to the Sales Agreement, we may offer, from time to time, to sell, in an "at the market offering," shares of our common stock up to an aggregate offering price of up to $50.0 million.

During the year ended December 31, 2024, we received $3.7 million from the exercise of warrants resulting in the issuance of 244,833 shares of common stock. No warrants were outstanding as of December 31, 2025.

Cash Flows

The following table shows a summary of our cash flows for the years indicated (in thousands):

For the Year Ended December 31,

Net cash used in operating activities $ (29,762 ) $ (21,030 )

Net cash used in investing activities (23 ) (19 )

Net cash provided by financing activities — 3,673

We have incurred net losses and negative operating cash flows since inception. For the year ended December 31, 2025, we recorded a net loss of $34.8 million and used $29.8 million of cash in operating activities. As of December 31, 2025, we had $41.3 million in unrestricted cash and cash equivalents and working capital of $37.4 million. We have not yet established an ongoing source of revenue sufficient to cover our operating costs and allow us to continue as a going concern. Our ability to continue as a going concern is dependent on obtaining adequate capital to fund operating losses until we become profitable. We plan to obtain additional capital resources by selling our equity securities as well as short-term borrowing from banks, stockholders or other related parties, if needed. However, we cannot assure you that we will be successful in accomplishing any of these plans and, if we are unable to obtain adequate capital, we could be forced to cease operations or substantially curtail our activities. We do not anticipate any revenue until our pharmaceutical programs are developed, including receipt of all necessary regulatory approvals, and we successfully commercialize these programs. These conditions raise substantial doubt as to our ability to continue as a going concern. As of the date of filing this Annual Report, we expect our existing resources to be sufficient to fund our planned operations for the next 12 months; however, additional capital resources will be needed to fund operations longer.

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Net Cash Flows from Operating Activities. Net cash used in operating activities was $29.8 million for the year ended December 31, 2025, compared to net cash used in operating activities of $21.0 million in 2024, an increase of $8.8 million. Cash used in operating activities for the year ended December 31, 2025 consisted primarily of our net loss of $34.8 million, adjusted for non-cash items such as non-cash stock-based compensation expense of $2.6 million and partially offset by net cash inflows from a change in our operating assets and liabilities of $1.9 million. Cash used in operating activities was $21.0 million for the year ended December 31, 2024 and consisted primarily of our net loss of $25.5 million, adjusted for non-cash items such as stock-based compensation expense of $2.3 million, non-cash impairment charge on investment in equity securities of $1.7 million and net cash outflows from a change in our operating assets and liabilities of $1.1 million.

Net Cash Flows from Investing Activities. Net cash used in investing activities was $23 thousand for the year ended December 31, 2025, compared to net cash used in investing activities of $19 thousand for the year ended December 31, 2024. Current and prior year cash used in investing activities was related primarily to purchases of new computers.

Net Cash Flows from Financing Activities. We received no net cash flows from financing activities for the year ended December 31, 2025 compared to net cash provided by financing activities of $3.7 million for 2024. The $3.7 million net cash provided by financing activities for the year ended December 31, 2024 consisted primarily of cash proceeds from the exercise of warrants.

Funding Requirements

We expect to incur ongoing operating losses for the foreseeable future as we continue to develop our planned therapeutic programs, including related clinical studies and other programs in the pipeline. Our future funding requirements will depend on many factors, including:

•

the costs of manufacturing drugs under development, the costs associated with clinical and non-clinical trials and associated salaries and benefits;

•

the extent to which we enter into contracts or invest in third parties in order to further develop our drug candidates;

•

the costs of preparing, filing and prosecuting patent applications, maintaining and enforcing our intellectual property rights and defending other intellectual property-related claims; and

•

the costs and fees associated with the discovery, acquisition or license of additional product candidates or technologies.

Substantial doubt exists about our ability to continue as a going concern. If we are unable to raise additional capital when needed on reasonable terms, if at all, we could be forced to cease operations or substantially curtail our activities. Our future capital uses and requirements will depend on the time and expenses needed to begin and continue clinical trials for our new drug developments.

Additional funding may not be available to us on acceptable terms or at all. Continued uncertain market and macroeconomic conditions, including due to inflationary pressures, high interest rates, general economic slowdown or a recession, foreign exchange rate volatility, financial institution instability, changes in monetary policy, changes in trade policies including tariffs and other trade restrictions or the threat of such actions, and increasing geopolitical instability, may limit our ability to access capital. In addition, the terms of any financing may adversely affect the holdings or the rights of our stockholders. For example, we may raise additional funds by issuing equity securities or by equity offerings, collaboration agreements, debt financings or licensing arrangements.

If adequate funds are not available, we may be required to terminate, significantly modify or delay our development programs, reduce our planned commercialization efforts, or obtain funds through collaborators that may require us to relinquish rights to our technologies or product candidates that we might otherwise seek to develop or commercialize independently. Further, we may elect to raise additional funds even before we need them if we believe the conditions for raising capital are favorable.

Contractual Obligations

Our contractual obligations represent our future cash commitments and liabilities under agreements with third-party clinical trial service providers. Apart from contracts with one third-party clinical trial service provider, such agreements are cancellable upon written notice by us. The non-cancellable contracts expire upon completion of the clinical trial and release of the final report, or the contract may be terminated by the clinical trial service provider, by the FDA or another governmental agency. As of December 31, 2025, our estimated non-cancellable commitment was $7.0 million, which will be paid over the term of the clinical trials.

Off-Balance Sheet Arrangements

We do not currently have, nor have we ever had, any relationships with unconsolidated entities or financial partnerships, such as entities often referred to as structured finance or special purpose entities, established for the purpose of facilitating off-balance sheet arrangements or other contractually narrow or limited purposes. In addition, we do not engage in trading activities involving non-exchange traded contracts.

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Recently Adopted Accounting Pronouncements

Refer to Note 3 to these Consolidated Financial Statements.

Recently Issued Accounting Pronouncements

Refer to Note 3 to these Consolidated Financial Statements.

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ITEM 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

As a smaller reporting company, we are not required to provide the information required by this item pursuant to Item 305(e) of Regulation S-K.

ITEM 8. FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA

The financial statements required by this item are set forth beginning on page 61 of this Annual Report and are incorporated herein by reference.

ITEM 9. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL DISCLOSURE

None.

ITEM 9A. CONTROLS AND PROCEDURES

Evaluation of Disclosure Controls and Procedures

Our management, with the participation of our Principal Executive Officer and Principal Financial Officer, conducted an evaluation of the effectiveness of our disclosure controls and procedures as of December 31, 2025, pursuant to Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934, as amended (the Exchange Act).

Our disclosure controls and procedures are designed to ensure that information required to be disclosed in our reports that are filed or furnished under the Exchange Act are recorded, processed, summarized and reported within the time periods specified in the rules and forms of the SEC. Disclosure controls and procedures include, without limitation, controls and procedures designed to ensure that information required to be disclosed in our reports filed or furnished under the Exchange Act is accumulated and communicated to our management, including our Principal Executive Officer and Principal Financial Officer, as appropriate, to allow timely decisions regarding required disclosure. Management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving their objectives, and management necessarily applies its judgment in evaluating the cost-benefit relationship of possible controls and procedures.

Based on the evaluation of our disclosure controls and procedures as of December 31, 2025, our Principal Executive Officer and Principal Financial Officer concluded that, as of such date, our disclosure controls and procedures were effective at the reasonable assurance level.

Management’s Annual Report on Internal Control Over Financial Reporting

Our management is responsible for establishing and maintaining adequate internal control over financial reporting (pursuant to Rules 13a-15(f) and 15d-15(f) under the Exchange Act). Our internal control over financial reporting includes policies and procedures designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external reporting purposes in accordance with generally accepted accounting principles in the United States.

Under the supervision and with the participation of our management, including our Principal Executive Officer and Principal Financial Officer, we conducted an evaluation of the effectiveness of our internal control over financial reporting as of December 31, 2025, based on the Framework in Internal Control—Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission. Based on our evaluation under this framework, our management concluded that our internal control over financial reporting was effective as of December 31, 2025. Because we are a non-accelerated filer, our independent registered public accounting firm is not required to attest to or issue a report on the effectiveness of our internal control over financial reporting.

Changes in Internal Control Over Financial Reporting

There have been no changes in our internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) of the Exchange Act) during the quarter ended December 31, 2025, that have materially affected or are reasonably likely to materially affect, our internal control over financial reporting.

ITEM 9B. OTHER INFORMATION

(a) Trading Plans

During the quarter ended December 31, 2025, no director or Section 16 officer adopted or terminated any Rule 10b5-1 trading arrangements or non-Rule 10b5-1 trading arrangements (in each case, as defined in Item 408(a) of Regulation S-K).

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ITEM 9C. DISCLOSURE REGARDING FOREIGN JURISDICTIONS THAT PREVENT INSPECTIONS

Not applicable.

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PART III

ITEM 10. DIRECTORS, EXECUTIVE OFFICERS AND CORPORATE GOVERNANCE

Except as indicated below, the other information required by this item is incorporated by reference to the sections entitled "Election of Directors," "Executive Officers," "Board Committees," "Insider Trading Policy,"and, as applicable, "Delinquent Section 16(a) Reports" in our Definitive Proxy Statement for our 2026 Annual Meeting of Stockholders(the Proxy Statement).

We have adopted a Code of Business Conduct and Ethics (the Code of Conduct) that applies to all of our directors, officers and employees, including our principal executive, principal financial and principal accounting officers, or persons performing similar functions. Our Code of Conduct is posted on our website located at https://investors.atossatherapeutics.com/ under "Corporate Governance." We intend to disclose future amendments to certain provisions of the Code of Conduct, and waivers of the Code of Conduct granted to executive officers and directors, on the website within four business days following the date of the amendment or waiver.

ITEM 11. EXECUTIVE COMPENSATION

The information required by this item is incorporated by reference to the sections entitled "Executive Compensation," "Director Compensation" and "Compensation Committee Interlocks" in our Proxy Statement.

ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT AND RELATED STOCKHOLDER MATTERS

The information required by this item is incorporated by reference to the sections entitled "Executive Compensation- Equity Compensation Plan Information" and "Security Ownership of Beneficial Owners and Management" in our Proxy Statement.

ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS, AND DIRECTOR INDEPENDENCE

The information required by this item is incorporated by reference to the sections entitled "Certain Relationships and Related- Party Transactions" and "Corporate Governance" in our Proxy Statement.

ITEM 14. PRINCIPAL ACCOUNTANT FEES AND SERVICES

The information required by this item is incorporated by reference to the section entitled "Ratification of the Selection of the Independent Registered Public Accounting Firm" in our Proxy Statement.

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PART IV

ITEM 15. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES

(a)

The following documents are filed as a part of this Annual Report:

1. Financial Statements

Report of Independent Registered Public Accounting Firm (EY; PCAOB ID #42) 59

Consolidated Balance Sheets 61

Consolidated Statements of Operations 62

Consolidated Statements of Stockholders' Equity 63

Consolidated Statements of Cash Flows 64

Notes to Consolidated Financial Statements 65

2. Financial Statement Schedules

All financial statement schedules are omitted because they are not required or the required information is included in the consolidated financial statements or notes thereto.

3. Exhibits

See the Exhibit Index on page77 of this Annual Report.

ITEM 16. FORM 10-K SUMMARY

None.

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Report of Independent Registered Public Accounting Firm

To the Stockholders and the Board of Directors of Atossa Therapeutics, Inc.

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Atossa Therapeutics, Inc. (the Company) as of December 31, 2025 and 2024, the related consolidated statements of operations, stockholders’ equity and cash flows for each of the two years in the period ended December 31, 2025, and the related notes (collectively referred to as the “consolidated financial statements”). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company at December 31, 2025 and 2024, and the results of its operations and its cash flows for each of the two years in the period ended December 31, 2025, in conformity with U.S. generally accepted accounting principles.

The Company's Ability to Continue as a Going Concern

The accompanying consolidated financial statements have been prepared assuming that the Company will continue as a going concern. As discussed in Note 2 to the financial statements, the Company has suffered recurring losses from operations and has stated that substantial doubt exists about the Company’s ability to continue as a going concern. Management's evaluation of the events and conditions and management’s plans regarding these matters are also described in Note 2. The consolidated financial statements do not include any adjustments that might result from the outcome of this uncertainty.

Basis for Opinion

These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on the Company’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Company's internal control over financial reporting. Accordingly, we express no such opinion.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current period audit of the financial statements that was communicated or required to be communicated to the audit committee and that: (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of the critical audit matter does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Accrued and prepaid research and development expenses

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/s/ Ernst & Young LLP

We have served as the Company’s auditor since 2023.

Seattle, Washington

March 25, 2026

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ATOSSA THERAPEUTICS, INC.

CONSOLIDATED BALANCE SHEETS

(amounts in thousands, except share and per share data)

As of December 31,

Assets

Current assets

Prepaid expenses and other current assets 1,128 1,165

Liabilities and stockholders' equity

Current liabilities

Commitments and contingencies (Note 13) — —

Stockholders' equity

Total liabilities and stockholders' equity $ 47,608 $ 76,444

The accompanying notes are an integral part of these Consolidated Financial Statements.

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ATOSSA THERAPEUTICS, INC.

CONSOLIDATED STATEMENTS OF OPERATIONS

(amounts in thousands, except share and per share data)

For the Year Ended December 31,

Operating expenses

Impairment charge on investment in equity securities — (1,710 )

Other expense, net (6 ) (223 )

Income tax benefit — —

Net loss per share of common stock - basic and diluted $ (4.04 ) $ (3.04 )

The accompanying notes are an integral part of these Consolidated Financial Statements.

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ATOSSA THERAPEUTICS, INC.

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY

(amounts in thousands, except share data)

Convertible Preferred Stock Common Stock Treasury Stock

Additional Total

Issuance of common stock upon option exercise — — 22,934 4 269 — — 273

Stock-based compensation — — — — 2,292 — — 2,292

Stock-based compensation — — — — 2,646 — — 2,646

The accompanying notes are an integral part of these Consolidated Financial Statements.

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ATOSSA THERAPEUTICS, INC.

CONSOLIDATED STATEMENTS OF CASH FLOWS

(in thousands)

For the Year Ended December 31,

CASH FLOWS FROM OPERATING ACTIVITIES

Adjustments to reconcile net loss to net cash used in operating activities

Impairment charge on investment in equity securities — 1,710

Loss on disposal of assets — 7

Changes in operating assets and liabilities:

Prepaid materials (983 ) (611 )

Prepaid expenses and other current assets 37 997

Accrued expenses 388 (54 )

Other current liabilities (410 ) (296 )

Net cash used in operating activities (29,762 ) (21,030 )

CASH FLOWS FROM INVESTING ACTIVITIES

Purchase of property and equipment (23 ) (19 )

Net cash used in investing activities (23 ) (19 )

CASH FLOWS FROM FINANCING ACTIVITIES

Proceeds from exercise of warrants — 3,673

Net cash provided by financing activities — 3,673

NET DECREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH (29,785 ) (17,376 )

CASH, CASH EQUIVALENTS AND RESTRICTED CASH, BEGINNING BALANCE 71,194 88,570

CASH, CASH EQUIVALENTS AND RESTRICTED CASH, ENDING BALANCE $ 41,409 $ 71,194

RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH

Total cash, cash equivalents and restricted cash $ 41,409 $ 71,194

NON-CASH INVESTING AND FINANCING ACTIVITIES

Common stock issued upon cashless exercise of stock options $ — $ 273

Conversion of Series B convertible preferred stock to common stock $ 5 $ —

The accompanying notes are an integral part of these Consolidated Financial Statements.

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ATOSSA THERAPEUTICS, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

NOTE 1: NATURE OF OPERATIONS

Atossa Therapeutics, Inc. (the Company) was incorporated on April 30, 2009, in the State of Delaware to develop and market medical devices, laboratory tests and therapeutics to address breast health conditions. The Company is focused on developing proprietary innovative medicines in areas of significant unmet medical need in oncology, with a focus on breast cancer and other breast conditions, as well as other rare diseases.

NOTE 2: GOING CONCERN

The Company's consolidated financial statements are prepared under the going concern basis of accounting, which contemplates the realization of assets and satisfaction of liabilities in the normal course of business. The Company has incurred net losses and negative operating cash flows since inception. For the year ended December 31, 2025, the Company recorded a net loss of $34.8 million and used $29.8 million of cash in operating activities. As of December 31, 2025, the Company had $41.3 million in unrestricted cash and cash equivalents and working capital of $37.4 million. The Company has not yet established an ongoing source of revenue sufficient to cover its operating costs and allow it to continue as a going concern. The ability of the Company to continue as a going concern is dependent on the Company obtaining adequate capital to fund operating losses until it becomes profitable. These conditions raise substantial doubt as to the Company's ability to continue as a going concern. The accompanying consolidated financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts and classification of liabilities should the Company be unable to continue as a going concern.

In order to alleviate the conditions that raise substantial doubt, the Company will need, among other things, additional capital resources. Management plans to obtain such resources for the Company include obtaining capital from the sale of its equity securities as well as short-term borrowings from banks, stockholders or other related parties if needed. However, management cannot provide any assurance that the Company will be successful in accomplishing any of its plans.

The ability of the Company to continue as a going concern is dependent upon its ability to successfully accomplish the plans described in the preceding paragraphs and eventually to secure other sources of financing and attain profitable operations.

NOTE 3: SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Basis of Presentation

These Consolidated Financial Statements have been prepared pursuant to the rules of the Securities and Exchange Commission (the SEC) and in accordance with GAAP. The accompanying Consolidated Financial Statements include the financial statements of Atossa Therapeutics, Inc. and its wholly-owned subsidiaries. All significant intercompany transactions and balances have been eliminated in consolidation.

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Significant estimates and assumptions reflected in these financial statements include the valuation of the investment in non-marketable equity securities, stock-based compensation expense, and prepaid or accrued clinical trial balances at the end of any reporting period. Actual results could differ materially from the Company’s estimates.

Reverse Stock Split

On February 2, 2026, the Company effected a 1-for-15 reverse stock split of its issued and outstanding common stock (the Reverse Stock Split). As a result of the Reverse Stock Split, each 15 shares of common stock issued and outstanding immediately prior to February 2, 2026 was automatically converted into one share of common stock. The Reverse Stock Split affected all common stockholders uniformly and did not alter any stockholders' percentage interest in the Company's equity, except to the extent that the Reverse Stock Split would result in a stockholder owning a fractional share. No fractional shares were issued in connection with the Reverse Stock Split. Stockholders who otherwise would be entitled to receive a fractional share instead were entitled to receive cash in lieu of such fractional share.

The Reverse Stock Split did not change the par value of the common stock or the authorized shares of common stock. The shares of common stock retain a par value of $0.18 per share. Accordingly, an amount equal to the par value of the decreased shares resulting from the reverse stock split was reclassified from “Common stock” to “Additional paid-in capital”.

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All common stock and per-share amounts in this Form 10-K have been retroactively restated to reflect the effect of the Reverse Stock Split.

Cashand Cash Equivalents

Cash and cash equivalents include unrestricted cash and all highly liquid instruments with original maturities of three months or less at the date of purchase. Cash equivalents consist primarily of amounts invested in money market accounts.

Restricted Cash

The Company’s restricted cash balance as of December 31, 2025 and 2024, consisted entirely of cash pledged as security for the Company’s issued commercial credit cards.

Concentration of Credit Risk

Financial instruments that potentially subject the Company to a concentration of credit risk consist primarily of deposits of cash and cash equivalents, including those deposited in money market deposit and prime money market fund accounts. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any material losses in such accounts and believes it is not exposed to significant risk. The Company invests its excess cash in a highly rated prime money market fund that management believes protects the Company from risk of default and impairment.

Clinical Trial and Preclinical Study Accruals

The Company makes estimates of its accrued expenses for clinical trial and preclinical study activities as of each balance sheet date in its financial statements based on the facts and circumstances known to the Company at that time. These accruals are based upon estimates of costs incurred and fees that may be associated with services provided by clinical trial investigational sites and Contract Research Organizations (CROs), and for other clinical trial-related activities. Payments under certain contracts with such parties depend on factors such as successful enrollment of patients, site initiation and progression through the various stages of the Company's clinical trials. In accruing for these services, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. If possible, the Company obtains information regarding unbilled services directly from these service providers. However, the Company may be required to estimate these services based on other information available to it. If the Company underestimates or overestimates the activities or fees associated with a study or service at a given point in time, adjustments to research and development expenses may be necessary in future periods. Historically, the Company's estimated accrued liabilities have approximated actual expense incurred. Subsequent changes in estimates may result in a material change in the Company's accruals.

Prepaid Materials

The Company capitalizes the purchase of certain raw materials, active pharmaceutical ingredients and related supplies for use in the manufacturing of drug products for use in its preclinical and clinical development programs, as it has determined that these materials have alternative future use. The Company can use these raw materials and related supplies in multiple clinical drug products, and therefore has future use independent of the development status of any particular drug program until it is utilized in the manufacturing process. The Company expenses the cost of materials when used. The Company periodically reviews these capitalized materials for continued alternative future use and writes down the asset to its net realizable value in the period in which an impairment is identified. Prepaid materials not expected to be used within 12 months of the balance sheet date are presented in Other assets on the Consolidated Balance Sheets.

Variable Interest Entities

The Company reviews agreements it enters into with third-party entities, pursuant to which the Company may have a variable interest in the entity, in order to determine if the entity is a variable interest entity (VIE). If the entity is a VIE, the Company assesses whether or not it is the primary beneficiary of that entity. In determining whether the Company is the primary beneficiary of an entity, the Company applies a qualitative approach that determines whether it has both (i) the power to direct the economically significant activities of the entity and (ii) the obligation to absorb losses of, or the right to receive benefits from, the entity that could potentially be significant to that entity. If the Company determines it is the primary beneficiary of a VIE, it consolidates that VIE into the Company's consolidated financial statements. The Company’s determination about whether it should consolidate such VIEs is made continuously as changes to existing relationships or future transactions may result in a consolidation or deconsolidation event. The Company currently does not consolidate any VIEs.

Investments in Equity Securities

The Company had one investment in non-marketable equity securities. This investment did not have a readily determinable fair value, so the Company elected to measure the investment at cost less any impairment, adjusted to fair value if there are observable price changes in orderly transactions for an identical or similar investment of the same issuer, in accordance with Accounting

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Standards Codification (ASC) 321, Investments – Equity Securities. At each reporting period, the Company performed an assessment to determine if it still qualified for this measurement alternative.

At each reporting period, the Company made a qualitative assessment considering impairment indicators to evaluate whether the investment was impaired. If a qualitative assessment indicated that the investment was impaired, the Company estimated the investment's fair value. If the fair value was less than the investment's carrying value, an impairment charge is recorded in the Consolidated Statements of Operations equal to the difference between the carrying value and fair value and a new basis in the investment was established. Refer to Note 4 “Investment in Equity Securities” to the Consolidated Financial Statements.

Other Assets

Other assets consist of property and equipment, prepaid materials and clinical deposits.

Fair Value Measurements

The Company has certain financial assets and liabilities recorded at fair value which have been classified as Level 1, 2 or 3 within the fair value hierarchy as described in the accounting standards for fair value measurements.

The fair value hierarchy is broken down into the three input levels summarized below:

•

Level 1: Quoted market prices in active markets for identical assets or liabilities;

•

Level 2: Other observable market-based inputs or unobservable inputs that are corroborated by market data; and

•

Level 3: Unobservable inputs that cannot be corroborated by market data that reflects the reporting entity's own assumptions.

The carrying amounts reflected in the accompanying Consolidated Balance Sheets for cash and cash equivalents, restricted cash, and accounts payable approximate their fair values due to their short-term nature. Refer to Note 9 to these Consolidated Financial Statements.

Researchand Development

Research and development (R&D) costs are expensed as incurred and consist of costs associated with research activities. R&D expenses include, for example, manufacturing expenses for the Company's drugs under development, expenses associated with preclinical studies, clinical trials and associated salaries, bonuses, stock-based compensation and benefits. R&D expenses also include an allocation of the CEO's salary and related benefits, including bonus and non-cash stock-based compensation expense, based on an estimate of his total hours spent on R&D activities. The Company's CEO is involved in the development of the Company's drug candidates and oversight of the related clinical trial activities and also acts as the Company's Chief Medical Officer.

Stock-based Compensation

The Company measures and recognizes compensation expense for all stock-based awards made to employees, officers, non-employee directors, and other key persons providing services to the Company, currently limited to stock options. Stock-based compensation is measured using the estimated grant date fair value and is recognized as an expense over the requisite service period, generally the vesting period. The Company has made a policy election to recognize forfeitures when they occur.

The fair value of each stock option grant is estimated using the Black-Scholes option-pricing model, which requires assumptions regarding the expected volatility of the price of the Company's common stock, the expected life of the options, an expectation regarding future dividends on the Company’s common stock, and a risk-free interest rate. The Company’s expected common stock price volatility assumption is based upon the historical volatility of its stock price. The Company has limited exercise history and has elected the simplified method for the expected life assumption for stock option grants, which averages the contractual term of the options of 10 years with the vesting term, typically one to four years. The dividend yield assumption of zero is based upon the fact that the Company has never paid cash dividends and presently has no intention of paying cash dividends in the future. The risk-free interest rate assumption is based upon prevailing short-term interest rates over the expected life of the options as of the grant date.

Income Taxes

The Company accounts for income taxes under the asset and liability method. Under this method, deferred tax assets and liabilities are determined based on differences between financial reporting and tax bases of assets and liabilities and are measured using enacted tax rates and laws that are expected to be in effect when the differences are expected to be recovered or settled. Realization of deferred tax assets is dependent upon future taxable income. A valuation allowance is recognized if it is more likely

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than not that some portion or all of a deferred tax asset will not be realized based on the weight of available evidence, including expected future earnings. The Company recognizes an uncertain tax position in its financial statements when it concludes that a tax position is more likely than not to be sustained upon examination based solely on its technical merits. Only after a tax position passes the first step of recognition will measurement be required. Under the measurement step, the tax benefit is measured as the largest amount of benefit that is more likely than not to be realized upon effective settlement. This is determined on a cumulative probability basis. The full impact of any change in recognition or measurement is reflected in the period in which such change occurs. The Company records any interest or penalties related to income taxes in income tax benefit in the Consolidated Statements of Operations.

Recently Adopted Accounting Pronouncements

For the year ended December 31, 2025, the Company adopted Accounting Standards Update (ASU) No. 2023-09, Income Taxes:Improvements to Income Tax Disclosures (Topic 740). This standard enhances disclosures related to income taxes, including the rate reconciliation and information on income taxes paid. See Note 12 to these Consolidated Financial Statements.

Recently Issued Accounting Pronouncements

In November 2024, the Financial Accounting Standards Board (the FASB) issued ASU No. 2024-03, Disaggregation of Income Statement Expenses (Topic 220-40). This standard requires business entities to disclose in a tabular format, on an annual and interim basis, purchases of inventory, employee compensation, depreciation, intangible asset amortization and depletion for each income statement line item that contains those expenses. The guidance is effective for public business entities in annual reporting periods beginning after December 15, 2026, and in interim periods within annual reporting periods beginning after December 15, 2027. Entities may apply the guidance prospectively or retrospectively. The Company is currently assessing the potential impact of this ASU.

NOTE 4: INVESTMENT IN EQUITY SECURITIES

The Company held an investment in Dynamic Cell Therapies, Inc. (DCT), a U.S. private company that was in the pre-clinical stage of developing novel Chimeric Antigen Receptor (CAR) T-cell therapies based on technology licensed from a leading U.S. cancer treatment and research institution. The Company determined that DCT was a VIE however, the Company did not consolidate DCT because it did not have the power to direct DCT’s economically significant activities. The Company had no obligation to provide any future funding to DCT.

The Company considered qualitative and quantitative impairment factors in determining if there were any signs of impairment of this investment as of September 30, 2024. Specifically, the Company considered continued concerns about the investee's ability to continue as a going concern, due to negative cash flows from operations and its inability to raise additional funding during the three and nine months ended September 30, 2024. Based on these impairment indicators, the Company performed a quantitative fair value measurement as of September 30, 2024. The impairment of the Company's Investment in equity securities required the estimation of fair value using unobservable inputs (a level 3 fair value measurement). The Company used the dynamic options approach, which required assumptions regarding (i) the expected average volatility of comparable companies, (ii) the expected term of the Company's investment, and (iii) an estimation of an appropriate risk-free interest rate over the term of the Company's investment. The expected stock price volatility assumption was based upon the average historic volatility of comparable public clinical stage immunotherapy or CAR-T companies. The expected term of the Company's investment was 3.0 years and the risk-free interest rate used was based upon prevailing short-term interest rates over the expected term of the investment. The dynamic options approach was weighted at a 5% outcome probability. An adjusted book value approach was also considered and weighted at a 95% probability due to (i) DCT's limited cash on hand at the time, (ii) the status of fundraising efforts and (iii) the subsequent decision by DCT to lay off all employees and wind down operations. Based on the valuation, the Company concluded that the investment was impaired, and accordingly, an impairment charge of $1.7 million was recorded in the Consolidated Statements of Operations for the year ended December 31, 2024.

NOTE 5: PREPAID EXPENSES AND OTHER CURRENT ASSETS

Prepaid expenses and other current assets consisted of the following (in thousands):

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As of December 31, As of December 31,

Prepaid pre-clinical and clinical trial deposits $ 410 $ 350

Prepaid professional services 68 68

Total prepaid expenses and other current assets $ 1,128 $ 1,165

NOTE 6: ACCRUED EXPENSES

Accrued expenses consisted of the following (in thousands):

As of December 31, As of December 31,

Accrued pre-clinical and clinical trial costs $ 661 $ 700

Accrued professional services and other 646 219

Total accrued expenses $ 1,307 $ 919

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NOTE 7: PAYROLL LIABILITIES

Payroll liabilities consisted of the following (in thousands):

As of December 31, As of December 31,

Accrued payroll and benefits 665 331

Total payroll liabilities $ 1,558 $ 1,862

NOTE 8: RESEARCH AND DEVELOPMENT TAX REBATE LIABILITY

In 2017, the Company formed a wholly owned subsidiary in Australia called Atossa Genetics AUS Pty Ltd. The purpose of this subsidiary is to perform R&D activities, including some of the Company's clinical trials. Australia offers R&D cash rebates on qualified R&D activities incurred in the country. The Australian R&D tax incentive program is a self-assessment program, and as such, the Australian Taxation Office (ATO) has the right to review the Company’s program and related expenditures for a period of four years following the tax return filing date. If a review were to occur, a qualified program and related expenditures could be disqualified by the ATO with interest and penalties. Based on the Company's evaluation of the ATO's taxpayer alert in December 2023, the Company believes that it is not reasonably assured that the full tax position would be sustained under audit. Accordingly, as of December 31, 2025 and 2024, a liability of $1.1 million and $1.5 million, respectively, was included in Other current liabilities in the Consolidated Balance Sheets.

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NOTE 9: FAIR VALUE OF FINANCIAL INSTRUMENTS

The following tables present the Company’s fair value hierarchy for all its financial assets and liabilities, by major security type, measured at fair value on a recurring basis (in thousands):

December 31, 2025 Estimated Fair Value Level 1 Level 2 Level 3

Assets:

December 31, 2024 Estimated Fair Value Level 1 Level 2 Level 3

Assets:

NOTE 10: STOCKHOLDERS’ EQUITY

Common Stock

On June 27, 2024, the Company's stockholders approved an amendment of the Company's Amended and Restated Certificate of Incorporation to increase the number of authorized shares of the Company's common stock, par value $0.18 per share, from 175,000,000 to 350,000,000.

Preferred Stock

The Company is authorized to issue a total of 10,000,000 shares of preferred stock, par value $0.001 per share. The Company has designated 750,000 shares of Series A junior participating preferred stock, par value $0.001 per share, 4,000 shares of Series A convertible preferred stock, par value $0.001 per share, 25,000 shares of Series B convertible preferred stock, par value $0.001 per share, and 20,000 shares of Series C convertible preferred stock, par value $0.001 per share, through the filings of certificates of designation with the Delaware Secretary of State. No shares of Series A junior participating preferred stock, Series A convertible preferred stock, or Series C convertible preferred stock, were outstanding as of December 31, 2025 and 2024.

Series B Convertible Preferred Stock

Conversion. Each share of Series B convertible preferred stock is convertible at the Company's option at any time, or at the option of the holder atany time, into the number of shares of the Company's common stock determined by dividing the $1,000 stated value per share of the Series B convertible preferred stock by a conversion price of $52.80 per share. In addition, the conversion price per share is subject to adjustment for stock dividends, distributions, subdivisions, combinations, or reclassifications. Subject to limited exceptions, a holder of the Series B convertible preferred stock will not have the right to convert any portion of the Series B convertible preferred stock to the extent that, after giving effect to the conversion, the holder, together with its affiliates, would beneficially own in excess of 9.99% of the number of shares of the Company's common stock outstanding immediately after giving effect to its conversion.

During the year ended December 31, 2025, certain holders of the Series B convertible preferred stock exercised their conversion option and converted an aggregate of 5 shares of Series B convertible preferred stock into 95 shares of the Company's common stock. No cash was exchanged in connection with the conversion. During the year ended December 31, 2024, there were no conversions of Series B convertible preferred stock.

Fundamental Transactions. In the event the Company effects certain mergers, consolidations, sales of substantially all of its assets, tender orexchange offers, reclassifications, or share exchanges in which its common stock is effectively converted into or exchanged for other securities, cash or property, the Company consummates a business combination in which another person acquires 50% of the outstanding shares of its common stock, or any person or group becomes the beneficial owner of 50% of the aggregate ordinary voting power represented by its issued and outstanding common stock, then, upon any subsequent conversion of the Series B convertible preferred stock, the holders of the Series B convertible preferred stock will have the right to receive any shares of the acquiring corporation or other consideration it would have been entitled to receive if it had been a holder of the number of shares of common stock then issuable upon conversion in full of the Series B convertible preferred stock.

Dividends. Holders of Series B convertible preferred stock shall be entitled to receive dividends (on an as-if-converted-to-common-stock basis) in the same form as dividends actually paid on shares of the common stock when, as and if such dividends are paid on shares of common stock. The Company's preferred stock contractually entitles the holders of such securities to participate in dividends but does not contractually require the holders of such securities to participate in losses of the Company.

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Voting Rights. Except as otherwise provided in the certificate of designation or as otherwise required by law, the Series B convertible preferred stock has no voting rights.

Liquidation Preference. Upon the Company's liquidation, dissolution or winding-up, whether voluntary or involuntary, holders of Series B convertible preferred stock will be entitled to receive out of the Company's assets, whether capital or surplus, the same amount that a holder of common stock would receive if the Series B convertible preferred stock were fully converted (disregarding for such purpose any conversion limitations under the certificate of designation) to common stock, which amounts shall be paid pari passu with all holders of common stock.

Redemption Rights. The Company is not obligated to redeem or repurchase any shares of Series B convertible preferred stock. Shares of Series B convertible preferred stock are not otherwise entitled to any redemption rights, or mandatory sinking fund or analogous provisions.

Warrants

There were no warrant exercises during the year ended December 31, 2025. During the year ended December 31, 2025, warrants granted in prior years expired as follows: 187,500 warrants granted in December 2020 expired on June 21, 2025; 300,000 warrants granted in January 2021 expired on July 8, 2025; and 701,667 warrants granted in March 2021 expired on September 22, 2025. No warrants remain outstanding at December 31, 2025.

During the year ended December 31, 2024, the Company received $3.7 million from the exercises of warrants resulting in the issuance of 244,833 shares of common stock.

NOTE 11: NET LOSS PER SHARE

Basic net loss per share of common stock is computed by dividing net loss attributable to common stockholders by the weighted average number of shares of common stock outstanding. Diluted net loss per share of common stock is computed by dividing net loss attributable to common stockholders by the weighted average number of shares of common stock that would have been outstanding during the period assuming the issuance of shares of common stock for all potentially dilutive shares of common stock outstanding. Potentially dilutive shares of common stock consist of future exercises of outstanding stock options, convertible preferred stock and common stock warrants. Because the inclusion of potential shares of common stock would be anti-dilutive for all periods presented, they have been excluded from the calculation.

The following table sets forth the weighted average number of shares of common stock excluded from the calculation of diluted net loss per share, because including them would be anti-dilutive:

Year Ended December 31,

Warrants to purchase common stock — 1,405,461

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NOTE 12: INCOME TAXES

The Company adopted ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, on a prospective basis effective January 1, 2025. A reconciliation of the income tax benefit calculated at the U.S. federal statutory rate to the recognized income tax benefit and effective income tax rate is as follows (in thousands, except percentages):

Amount Percent

Income tax benefit at the U.S. federal statutory rate $ (7,302 ) 21.0 %

State income taxes, net of federal income tax effect — 0.0 %

Foreign tax effects

Australia

Statutory tax rate difference between Australia and U.S. (31 ) 0.1 %

Change in valuation allowance 22 -0.1 %

Effect of changes in tax laws or rates enacted in the current period — 0.0 %

Effect of cross border tax laws (76 ) 0.2 %

Tax credits — 0.0 %

Change in valuation allowance 7,278 -20.9 %

Non taxable or non deductible items

Other non-taxable income & disallowed expenses 173 -0.5 %

Changes in unrecognized tax benefits — 0.0 %

Income tax benefit $ — 0.0 %

Expected federal income tax benefit at statutory rate $ (5,356 )

Disallowed R&D expenses 3

Non-taxable R&D rebate —

Other permanent items 235

Return to provision 57

Stock-based compensation 246

Foreign rate differential (76 )

Effect of change in valuation allowance 4,870

Income tax benefit $ —

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The following table summarizes the significant components of the Company's deferred tax assets and liabilities (in thousands):

As of December 31,

Deferred tax assets

Accrued vacation 45 47

Investment in equity securities 987 987

Net deferred tax assets — 47

Deferred tax liabilities

Bonus compensation — (47 )

Net deferred tax assets $ — $ —

As of December 31, 2025 and 2024, a valuation allowance was established against the Company's net deferred tax assets due to the uncertainty regarding the realization of such assets as evidenced by the cumulative losses from operations through December 31, 2025 and 2024. The total valuation allowance increased by $7.3 million for the year ended December 31, 2025 primarily as a result of an increase in net operating loss carryforwards, partially offset by a reduction in deferred tax assets related to previously capitalized R&D expenses.

The Company has incurred net operating losses since inception. At December 31, 2025, the Company had domestic federal net operating loss (NOL) carryforwards of $186.7 million and foreign NOL carryforwards of $1.7 million. The 2017 Tax Cut and Jobs Act (the Act) generally allows federal losses generated after 2017 to be carried forward indefinitely, but also limits the NOL deduction to the lesser of the NOL carryover or 80% of a corporation's taxable income (subject to Section 382 of the Internal Revenue Code of 1986, as amended (the IRC). Additionally, there is no carryback for losses generated after 2017. Losses generated prior to 2018 are deductible using the lesser of a corporation's NOL carryover or 100% of a corporation's taxable income and have a 20 year carryforward period. Federal NOL carryforwards generated prior to 2018 expire at various dates beginning 2029 through 2037. Foreign NOLs do not expire.

The future utilization of the federal NOL carryforwards to offset future taxable income may be subject to an annual limitation as a result of ownership changes that may have occurred previously or may occur in the future. The IRC limits a Company's ability to utilize certain NOL carry forwards in the event of a cumulative change in ownership in excess of 50% (by value) defined in the IRC. The Company has not completed a study to assess whether an ownership change, as defined by the IRC, had occurred since its inception.

The Company has no unrecognized tax positions as of December 31, 2025 or 2024 and does not believe there will be any material changes in its unrecognized tax positions over the next 12 months. The Company has not incurred any interest or penalties related to unrecognized tax positions for the years ended December 31, 2025 or 2024.

The Company files income tax returns in the U.S. and Australia. The Company has incurred net losses since inception and has not been audited for any open taxation years. As such, all tax years remain open for federal tax examinations in the U.S. For Australia, tax years from 2020 to present remain open and subject to audit.

NOTE 13: COMMITMENTS AND CONTINGENCIES

Litigation and Contingencies

On April 3, 2025, Intas Pharmaceuticals Ltd. (Intas) filed a Petition for Post Grant Review (PGR) with the U.S. Patent and Trademark Office’s (USPTO) Patent Trial and Appeal Board (PTAB) (the 391 PGR Petition) seeking to invalidate one of the

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Company’s issued patents (U.S. Patent No. 12,071,391) titled “Methods for Making and Using Endoxifen,” on the alleged grounds of anticipation, obviousness, lack of written description, and lack of enablement.

On April 3, 2025, Intas also filed a Petition for Inter Partes Review (IPR) with the USPTO’s PTAB (the 151 IPR Petition) seeking to invalidate one of the Company’s issued patents (U.S. Patent No. 11,261,151) titled “Methods for Making and Using Endoxifen” (together with U.S. Patent No. 12,071,391, the Patents) on the alleged grounds of anticipation and obviousness.

On November 3, 2025, the PTAB released a Decision Granting Institution of PGR for U.S. Patent No. 12,071,391 and a Decision Granting Institution of IPR for U.S. Patent No. 11,261,151. On January 26, 2026, the Company submitted responses to the 391 PGR Petition and the 151 IPR Petition. Final written decisions are expected for the PGR and IPR proceedings by November 3, 2026.

The Company intends to continue to vigorously contest the 391 PGR Petition and the 151 IPR Petition and believes that the Patents were properly granted and include valid and enforceable claims and that the risk of experiencing financial loss related to the Petitions is remote. However, there can be no assurance that the Company will prevail in contesting either the 391 PGR Petition or the 151 IPR Petition.

From time to time, the Company is subject to other legal proceedings and claims that arise in the ordinary course of its business. The Company believes that these matters do not have a material effect, individually or in the aggregate, on its financial position, results of operations or cash flows.

Contractual Obligations

Contractual obligations represent the Company's future cash commitments and liabilities under agreements with third party clinical trial service providers. Apart from contracts with one third-party clinical trial service provider, such agreements are cancellable upon written notice by the Company. The non-cancellable contracts expire upon completion of the clinical trial and release of the final report, or the contracts may be terminated by the clinical trial service provider, by the FDA or another governmental agency. As of December 31, 2025, the Company's estimated non-cancellable commitment was $7.0 million.

NOTE 14: STOCK BASED COMPENSATION

On May 15, 2020, the stockholders of the Company approved the 2020 Stock Incentive Plan (the 2020 Plan) to provide for the grants of equity-based awards to employees, officers, non-employee directors and other key persons providing services to the Company. No awards may be granted under the 2020 Plan after June 27, 2034. An aggregate of 2,000,000 shares of common stock is reserved for issuance in connection with awards granted under the 2020 Plan. As of December 31, 2025, 679,462 shares were available for future grants under the 2020 Plan.

The Company granted 344,548 and 313,419 options to purchase shares of common stock to employees and directors during the years ended December 31, 2025 and 2024, respectively. The weighted average grant date fair value of options granted during the years ended December 31, 2025 and 2024 was $14.72 and $13.20, respectively. No options were exercised during the year ended December 31, 2025. There were 22,933 options exercised during the year ended December 31, 2024.

The fair values of stock options granted were calculated using the Black-Scholes option-pricing model applying the following assumptions:

Year Ended December 31,

Dividend yield — —

The Company recognized stock-based compensation expense in the Consolidated Statements of Operations as follows (in thousands):

Year Ended December 31,

General and administrative $ 2,081 $ 1,647

Research and development 565 645

Total stock-based compensation expense $ 2,646 $ 2,292

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The following table shows a summary of all stock option activity for the year ended December 31, 2025:

Exercised —

As of December 31, 2025, there were 239,196 unvested options outstanding, and the related unrecognized total compensation cost associated with these options was $2.2 million. This expense is expected to be recognized over a weighted-average period of 1.74 years.

NOTE 15: DEFINED CONTRIBUTION PLAN

The Company has a defined contribution plan to which employees of the Company may defer contributions for income tax purposes. Participants are eligible to receive employer matching contributions up to 6% of deferrals. Employees may also be eligible for a discretionary match over 6%. Defined contribution plan employer matching contributions for the years ended December 31, 2025 and 2024 were $0.4 million and $0.3 million, respectively.

NOTE 16: SEGMENTS

The Company operates as a single segment. Operating segments are identified as the components of an enterprise of which separate discrete financial information is available for evaluation by the Chief Operating Decision Maker (the CODM) in making decisions regarding resource allocation and in assessing performance. To date, the Company's CODM has made such decisions and assessed performance at the Company-level as a single segment using information at the consolidated financial statement level.

The CODM is Steven C. Quay, M.D., Ph D. Chairman, President and CEO. The CODM utilizes Net Loss from the Consolidated Statement of Operations for the measure of segment profit or loss.

NOTE 17: SUBSEQUENT EVENT

On February 20, 2026, the Company entered into the At the Market Offering Agreement (the Sales Agreement), with Rodman & Renshaw LLC (the Sales Agent), pursuant to which the Company may offer and sell from time to time up to $50,000,000 of shares of the Company’s common stock, par value $0.18 per share (the Shares), through the Sales Agent as agent or principal. On February 19, 2026, the Company delivered written notice to Jefferies LLC indicating that it was terminating the Open Market Sale AgreementSM (the Prior Agreement) by and between the Company and Jefferies LLC, dated November 19, 2024, effective as of February 19, 2026. The Company is not subject to any termination penalties related to the termination of the Prior Agreement. The Company did not undertake any sales of its common stock pursuant to the Prior Agreement.

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EXHIBIT INDEX

Incorporated by Reference Herein or Filed or Furnished Herewith

ExhibitNo. Description Form Date

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21.1 List of Subsidiaries Filed herewith

23.1 Consent of Ernst & Young, LLP Filed herewith

101.INS Inline XBRL Instance Document

# Indicates management contract or compensatory plan, contract or agreement.

(1) The certification that accompanies this Annual Report on Form 10-K is not deemed filed with the Securities and Exchange Commission and is not to be incorporated by reference into any filing of the Company under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, whether made before or after the date of this Annual Report on Form 10-K, irrespective of any general incorporation language contained in such filing.

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SIGNATURES

Pursuant to the requirements Section 13 or 15(d) of the Securities Exchange Act of 1934, the Registrant, a corporation organized and existing under the laws of the State of Delaware, has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized in the City of Seattle, State of Washington, on March 25, 2026.

Atossa Therapeutics, Inc.

By: /s/ Steven C. Quay

Steven C. Quay, M.D., Ph.D.

Chairman, President and Chief Executive Officer

POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below hereby constitutes and appoints Steven C. Quay and Mark J. Daniel, and each of them acting individually, as his or her true and lawful attorneys-in-fact and agents, each with full power of substitution, for him or her in any and all capacities, to sign any and all amendments to this Annual Report on Form 10-K and to file the same, with exhibits thereto and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, full power and authority to do and perform each and every act and thing requisite and necessary to be done in connection therewith, as fully for all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents, or his or their substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, this Annual Report on Form 10-K has been signed by the following persons in the capacities and on the dates indicated.

Signature Office(s) Date

Steven C. Quay, M.D., Ph.D. (Principal Executive Officer)

/s/ Mark J. Daniel Chief Financial Officer March 25, 2026

Mark J. Daniel (Principal Financial and

Accounting Officer)

/s/ Richard I. Steinhart Director March 25, 2026

Richard I. Steinhart

/s/ Shu-Chih Chen Director March 25, 2026

Shu-Chih Chen, Ph.D.

/s/ Jonathan F. Finn Director March 25, 2026

Jonathan F. Finn

/s/ Stephen J. Galli Director March 25, 2026

Stephen J. Galli, M.D.

/s/ H. Lawrence Remmel Director March 25, 2026

H. Lawrence Remmel

/s/ Tessa Cigler Director March 25, 2026

Tessa Cigler, M.D., M.P.H.

ATOS US Equity

ATOS · 10-K · period ended 2025-12-31

ITEM 7. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

ITEM 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

ITEM 8. FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA

ITEM 9. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL DISCLOSURE

ITEM 9A. CONTROLS AND PROCEDURES

ITEM 9B. OTHER INFORMATION

ITEM 9C. DISCLOSURE REGARDING FOREIGN JURISDICTIONS THAT PREVENT INSPECTIONS

ITEM 10. DIRECTORS, EXECUTIVE OFFICERS AND CORPORATE GOVERNANCE

ITEM 11. EXECUTIVE COMPENSATION

ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT AND RELATED STOCKHOLDER MATTERS

ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS, AND DIRECTOR INDEPENDENCE

ITEM 14. PRINCIPAL ACCOUNTANT FEES AND SERVICES

ITEM 15. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES

ITEM 16. FORM 10-K SUMMARY

ATOS US Equity☆

ATOS · 10-K · period ended 2025-12-31

ITEM 7. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

ITEM 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

ITEM 8. FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA

ITEM 9. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL DISCLOSURE

ITEM 9A. CONTROLS AND PROCEDURES

ITEM 9B. OTHER INFORMATION

ITEM 9C. DISCLOSURE REGARDING FOREIGN JURISDICTIONS THAT PREVENT INSPECTIONS

ITEM 10. DIRECTORS, EXECUTIVE OFFICERS AND CORPORATE GOVERNANCE

ITEM 11. EXECUTIVE COMPENSATION

ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT AND RELATED STOCKHOLDER MATTERS

ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS, AND DIRECTOR INDEPENDENCE

ITEM 14. PRINCIPAL ACCOUNTANT FEES AND SERVICES

ITEM 15. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES

ITEM 16. FORM 10-K SUMMARY

ATOS US Equity