SMMT 10-K & 10-Q changes, risk factors and insider trading

We are a development-stage company and we cannot assureensure profitability. We expect to continue to generate operating losses for the foreseeable future. Until we can generate substantial revenue and achieve profitability, we will need to raise additional capital to fund ongoing operations and capital needs. Since inception, we have incurred significant operating losses. During the year ended December 31, 2024,2025, we incurred a net loss of $221.3$1,079.6 million, and cash flows used in operating activities was $142.1$322.9 million. As of December 31, 20242025 we had an accumulated deficit of $1,214.6$2,294.2 million, cash and cash equivalents of $104.9$225.3 million, short-term investments in U.S. treasury securities of $307.5$488.2 million, and current and long-term research and development tax credits receivable of $1.3$0.9 million. These losses could continue for the next several years as we invest in clinical development of ivonescimab. We expect to continue to generate operating losses for the foreseeable future. Until we can generate substantial revenue and achieve profitability, we will need to raise additional capital to fund ongoing operations and capital needs.

Assuming we obtain marketing approval for any of our product candidates, we will need to transition from a company with a research and development focus to a company capable of supporting commercial activities or seek an appropriate partner or partners to maximize the commercial opportunity of our products with a deal structure that maximizes our opportunities for profitability. We may encounter unforeseen expenses, difficulties, complicationscomplications, and delays, and may not be successful in such a transition.

Conducting preclinical testing and clinical trials is a time-consuming, expensiveexpensive, and uncertain process that takes years to complete, and we may never generate the necessary data or results required to obtain marketing approval or achieve product sales. In addition, our product candidates, if approved, may not achieve commercial success. Our commercial revenues, if any, will be derived from sales of products that we aremay not planning to havebe commercially available for several years, if at all. Additional financing may not be available to us on acceptable terms, or at all.

The License Agreement, as amended, calls for initial consideration payments of $515 million (of which $500 million was paid in 2023 and $15 million was paid in 2024), as well as total contingent payments by the Company of up to $4.56 billion, as Akeso will be eligible to receive regulatory milestones of up to $1.05 billion and commercial milestones of up to $3.51 billion, manysome of which will be due before the Company anticipates generating any revenue fromand thecommercial Licensemilestones Agreement.of up to $3.51 billion. We will need additional capital to fund our operations and payments under the License Agreement, which we may do via issuances of equity or debt or through global or regional partnerships in the Licensed Territory.

Generally, worldwide economic conditions remain uncertain, particularly due to the effects of the conflict between Russia and Ukraine andUkraine, the conflicts in the Middle East, including those in Gaza, Lebanon and Yemen, the escalating tensions in Venezuela and Greenland, and disruptions in the banking system and financial markets, including those in Japan, increased inflation and rising interest rates. The general economic and capital market conditions, both in the U.S. and worldwide, have been volatile in the past and at times have adversely affected the Company’s access to capital and increased the cost of capital. The ongoing geopolitical conflicts in various parts of the world, including but not limited to Russia, UkraineUkraine, andthe Middle East, Venezuela and Greenland, are difficult to predict and could adversely affect our business in the Licensed Territory as well as our ability to enroll patients and supply ivonescimab to various clinical sites in the world, resulting in adverse effects on our business and financial condition.

•protectingenforcing our rights in our intellectual property portfolio;

InPrior connection withto obtaining marketing approval from regulatory authorities (including the FDA, EMA, PMDA or any other regulatory authority in the Licensed Territory) for the sale of ivonescimab, or any other product candidate, we must complete preclinical development and then conduct extensive clinical trials to demonstrate the safety and efficacy of our product candidates in humans. Clinical testing is expensive, difficult to design and implement, can take many years to complete and is inherently uncertain as to outcome. A failure of one or more clinical trials can occur at any stage of testing. The outcome of preclinical testing and early clinical trials may not be predictive of the success of later clinical trials, and interim results of a clinical trial do not necessarily predict final results. In particular, due to the small number of patients in our early clinical trials, results from such trials may not be predictive of the outcome of later clinical trials. The design of a clinical trial can determine whether its results will support approval of a product, and flaws in the design of a clinical trial may not become apparent until the clinical trial is well advanced or completed. We have limited experience in designing clinical trials and may be unable to design and execute a clinical trial to support marketing approval. Moreover, preclinical and clinical data are often susceptible to varying interpretations and analyses, and many companies that have believed their product candidates performed satisfactorily in preclinical studies and clinical trials have nonetheless failed to obtain marketing approval of their products. ToFor date,instance, although we havebelieve notthat completedthe asafety clinicaland trialefficacy fordata ivonescimabgenerated in the LicensedHARMONi Territorystudy demonstrates that the ivonescimab regimen offers a potential treatment option for patients impacted by EGFR-mutant NSCLC in this setting with a favorable benefit-risk profile, FDA has noted that a statistically significant OS benefit is necessary to support marketing authorization in this setting. If the FDA does not agree with our analysis of the HARMONi data, they may delay or deny regulatory approval in this proposed indication, require us to resubmit the marketing application with additional data or information, or take other actions that could delay commercialization of ivonescimab and adversely impact our ability to generate revenue, our business and our operations. We cannot predict the results of suchour ongoing or future clinical trials.

As we expand into additional countries and sites for our current and additional clinical trials, we are required to obtain the regulatory approval of the applicable clinical trial applications with the respective regulatory authorities and approvals from central or local institutional review boards. We may decide to modify our plans to enter certain regions or countries based on the timelines and requirements fromfor the respective regulatory regions. If the process to obtain regulatory approvals in a given region or country places onerous requirements on the Company or if the Company cannot reasonably obtain such approvals without material delays to its plans, we may choose not to enter certain regions or countries for our clinical trials, which may delay the development of our product in those countries and impact the scope of our dataset and market for our products.

•our product candidates may have undesirable side effects or other unexpected characteristics, causing us or our investigators, regulators, institutional review boards or independent ethics committees to suspend or terminate the clinical trials; and

•preclinical tests or clinical trials not beginning as planned, needing to be restructured or not being completed on schedule, or at all.all; and

WeWith doour notBLA havesubmission ain salesQ4, or marketing infrastructure2025 and havethe noFDA’s experienceacceptance asfor afiling companythe BLA in January 2026, we are in the sale or marketingprocess of pharmaceuticalbuilding products,our althoughSales, certainMarketing employeesand doMarket Access organization. We have already hired our senior commercial leadership team with extensive experience in the sale and marketing of pharmaceutical products. In addition, we are in the process to build infrastructure of supporting operations to ensure a successful commercial launch. To achieve commercial success for any approved product, we must either develop a sales and marketing organization and/or outsource these functions to third parties.parties . If ivonescimab receives marketing approval, we may seek commercialization partners in some parts of the Licensed Territory. There are risks involved with establishing our own sales and marketing capabilities andas well as entering into arrangements with third parties to perform these services. For example, recruiting and training a sales force is expensive and time-consuming and could delay any product launch. If the commercial launch of a product candidate for which we recruit a sales force and establish marketing capabilities is delayed or does not occur for any reason, we would have prematurely or unnecessarily incurred these commercialization expenses. This may be costly, and our investment would be lost if we cannot retain or reposition our sales and marketing personnel.

•our inability to recruit, train and retain adequate numbers of effective sales and marketing personnel in a timely fashion;

The successful development, manufacturing and sale of biologics is a long, expensive and uncertain process. There are unique risks and uncertainties with biologics. For example, access to and supply of necessary biological materials, such as cell lines, may be limited and governmental regulations restrict access to and regulate the transport and use of such materials. In addition, the development, manufacturing and sale of biologics is subject to regulations that are often more complex and extensive than the regulations applicable to other pharmaceutical products. Manufacturing biologics, especially in large quantities, is often complex and may require the use of innovative technologies. Such manufacturing also requires facilities specifically designed and validated for this purpose and sophisticated quality assurance and quality control procedures. Biologics are also frequently costly to manufacture. Failure to successfully,successfully develop, manufacture and sell ivonescimab could adversely affect our business.

The development and commercialization of new drug products is highly competitive. We face competition with respect to our current product candidatescandidate and any products we may seek to develop or commercialize whether ourselves or through third-party partners, in the future from major pharmaceutical companies, specialty pharmaceutical companies and biotechnology companies worldwide.

For those patients having EGFR mutations, there are several targeted therapies that have also been approved in the front-line setting, including, but not limited to, osimertinib (AstraZeneca) with or without chemotherapy and amivantamab and lazertinib (both from Johnson & Johnson). The proposed indication for ivonescimab in the HARMONi clinical trial setting, post third-generation EGFR-TKIs such as osimertinib or lazertinib, may face competition from amivantamab plus chemotherapy, as well as clinical candidates such as as datopotamab deruxetecan (AstraZeneca and Daiichi Sankyo) and patritumab deruxtecan (Merck and Daiichi Sankyo).

There are several PD-(L)1/VEGF(R2) bispecific antibodies in development or with planned development globally. These include, but are not limited to BNT327,pumitamig (BNT327), which is owned by BioNTech SE,SE and being developed in a collaboration with Bristol Myers Squibb Co. since June 2025, which has begun conducting Phase III clinical studies globally, andPF-08634404 (PF’4404 / SSGJ-707), which was licensed globally, ex-China by Pfizer Inc. in July 2025, LM-299, which was licensed globally by Merck & Co., Inc. in November 2024.2024, and RC148, which was licensed outside of Greater China by AbbVie Inc. in January 2026.

Multiple in-class and related competitors for our product candidatescandidate are and can be developed, our competitive position could be compromised because it may be more difficult for us to obtain marketing approval for that product candidate and market acceptance of that product candidate due to a similar competitor. In addition, any product that competes with another approved product typically must demonstrate compelling advantages in efficacy, convenience, tolerability or safety, or some combination of these factors, to gain regulatory approvals, overcome price competition and be commercially successful.

Our primary product candidate, ivonescimab, is subject to the License Agreement from Akeso, which is revocable in certain circumstances, including in the event we do not achieve certain payment deadlines. Without the rights to the patents under the License Agreement, we will not be able to continue to develop ivonescimab.

•the impact on payments and costs associated with commercialization if there is blocking intellectual property inor orthe costs associated with prosecution, maintenance and enforcement of intellectual property under the Akeso License Agreement.

We have entered into the License Agreement pursuant to which we agreed to purchase a certain portion of drug substance and/or drug product for clinical and commercial supply, and the termination or Akeso’s breach of these agreements could have a material adverse effect on our business. Akeso’s drug substance and drug product may not comply with regulatory authority quality requirements or have sufficient stability for commercialization which may require additional investment and delay our development, approval and commercialization plans. Further, failure of Akeso to adequately transfer knowledge to Summit relating to any improvements in producing ivonescimab could have a material adverse effect on our business.

Further, failure of Akeso to adequately transfer knowledge to Summit relating to any improvements in producing ivonescimab could have a material adverse effect on our business. Manufacturing of biological compounds is inherently complex and establishing new manufacturing relationships with a third-party manufacturer may take longer, resulting in higher costs and potential inventory issues. Manufacturing processes may use materials which Summit may not be able to secure, requiring Summit to develop alternative processes and delay manufacturing. The product may not comply with regulatory authority quality requirements or have sufficient stability for commercialization, which may require additional manufacturing development and delays. As Summit is relying initially on supply from Akeso, any delays in obtaining import or export licenses may delay development.

Our likely future collaborators for any marketing, distribution, development, licensing or broader collaboration arrangements include large and mid-size pharmaceutical companies, regional and national pharmaceutical companies and biotechnology companies. Under our license and commercialization agreements we have, and under any such arrangements we enter into with any third parties in the futurefuture, we will likely have, limited control over the amount and timing of resources that our collaborators dedicate to the development or commercialization of our product candidates. Our ability to generate revenues from these arrangements will depend on our collaborators’ abilities and efforts to successfully perform the functions assigned to them in these arrangements.

Our current collaborations pose, and any future collaborationcollaborations likely will pose, numerous risks to us, including without limitation the following:

•collaborators may delay clinical trials, provide insufficient funding for a clinical trial program, stop a clinical trial or abandon a product candidate, repeat or conduct new or unsuccessful clinical trials or require a new formulation of a product candidate for clinical testing;

•collaborators could independently develop, or develop with third parties, products that compete directly or indirectly with our products or product candidates if the collaborators believe that competitive products are more likely to be successfully developed or can be commercialized under terms that are more economically attractive than ours;a collaborator with marketing and distribution rights to multiple products may not commit sufficient resources to the marketing and distribution of our product relative to other products;

•disputes may arise between the collaborator and usSummit as to the ownership of intellectual property arising during the collaboration;

We do not own or operate manufacturing facilities for the production of clinical or commercial supplies of our product candidates. We have limited personnel with experience in drug manufacturing and lack the resources and the capabilities to manufacture any of our product candidates on a clinical or commercial scale. We currently rely on third parties for supply of the active pharmaceutical ingredients ("API"), drug substance orand drug product,product in our product candidates. Our strategy is to outsource all manufacturing of our product candidates and products to third parties.

We have supply agreements with Akeso for supply of ivonescimab for use in clinical trials as well as for commercial supply. We have agreements with third-party manufacturers for development, validation and manufacturing of ivonescimab to secure the long-term clinical or commercial supply of our product candidates. We are in the process of setting up agreements with third party manufacturers for the long-term clinical and commercial supply of ivonescimab. We may be unable to conclude agreements for commercial supply with third-party manufacturers, or may be unable to do so on acceptable terms. The third-party manufacturers may not successfully carry out their contractual duties or obligations, the occurrence of which could substantially increase our costs and limit our supply of such product candidates. The demand for third-party manufacturer’smanufacturers’ services is very high, and such manufacturers could be subject to market transactions including mergers, acquisitions and other market consolidation transactions that limit their ability to provide products and services to us thereby increasing the time and cost it could take us to manufacture our product.

Third-party manufacturers, including Akeso, may not be able to comply with current good manufacturing practice (“cGMP”),cGMP, regulations or similar regulatory requirements outside the United States. Our failure, or the failure of our third-party manufacturers, including Akeso, to comply with applicable regulations could result in sanctions being imposed on us, including fines, injunctions, civil penalties, delays, suspension or withdrawal of approvals, license revocation, seizures or recalls of product candidates or products, operating restrictions and criminal prosecutions, any of which could significantly and adversely affect supplies of our product candidates.

If the third parties, including Akeso, that we engage to manufacture product for our preclinical tests and clinical trials should cease to continue to do so for any reason, including due to the novel coronavirus or another outbreak, we likely would experience delays in advancing these clinical trials while we identify and qualify replacement suppliers, and we may be unable to obtain replacement supplies on terms that are favorable to us. In addition, if we are not able to obtain adequate supplies of our product candidates or the drug substances used to manufacture them, it will be more difficult for us to develop our product candidates and compete effectively.

Our reliance on these third parties for clinical development activities reduces our control over these activities but does not relieve us of our responsibilities. For example, we remain responsible for ensuring that each of our clinical trials is conducted in accordance with the general investigational plan and protocols for the clinical trial. Moreover, the FDA requires us to comply with standards, commonly referred to as GCP, for conducting, recording and reporting the results of clinical trials to assureensure that data and reported results are credible and accurate and that the rights, integrity of data and confidentiality of clinical trial participants are protected. The EMA and PDMA impose similar requirements on us for products that are the subject of clinical trials in the E.U., including the U.K., and Japan.

Our ability to commercialize ivonescimab or any other product candidate successfully also will depend in part on the extent to which coverage and adequate reimbursement for these products and related treatments will be available from government health administration authorities, private health insurers and other organizations. Significant uncertainty exists as to the coverage and reimbursement status of any of our products for which we obtain regulatory approval. Government authorities and other third-party payors, such as private health insurers and health maintenance organizations, decide which medications they will pay for and establish reimbursement levels. AIn primarythe trendUnited States, although private third-party payors tend to follow Medicare practices, no uniform or consistent policy of coverage and reimbursement for drug products exists among third-party payors. Therefore, coverage and reimbursement for drug products can differ significantly from payor to payor as well as from state to state. Consequently, the coverage determination process is often a time-consuming and costly process that must be played out across many jurisdictions and different entities and that will require us to provide scientific, clinical and health economics support for the use of our products compared to current alternatives and do so to each payor separately, with no assurance that coverage and adequate reimbursement will be obtained and in thewhat U.S.time and E.U. healthcare industries and elsewhere is cost containment.frame.

There may be significant delays in obtaining coverage and reimbursement for newly approved drugs, and coverage may be more limited than the purposes for which the drug is approved by the applicable regulatory authority. Moreover, eligibility for coverage and reimbursement does not imply that any drug will be paid for in all cases or at a rate that covers our costs, including, but not limited to, research, development, intellectual property, manufacture, sale and distribution expenses. Interim reimbursement levels for new drugs, if applicable, may also not be sufficient to cover our costs and may not be made permanent. Reimbursement rates may vary according to the use of the drug and the clinical setting in which it is used, may be based on reimbursement levels already set for lower cost drugs, and may be incorporated into existing payments for other services. Net prices for drugs may be reduced by mandatory discounts or rebates required by government healthcare programs or private payors and by any future relaxation of laws that presently restrict imports of drugs from countries where they may be sold at lower prices than in the United States. In the United States, third-party payors often rely upon Medicare coverage policy and payment limitations in setting their own reimbursement policies. In the E.U., reference pricing systems and other measures may lead to cost containment and reduced prices. Our inability to promptly obtain and maintain coverage and adequate reimbursement rates from both government-funded and private payors for any approved products that we develop could have a material adverse effect on our operating results, our ability to raise capital needed to commercialize products and our overall financial condition.

•unexpected or unfavorable changes in regulatory requirements; and

The U.S. and Chinese governments have taken certain actions that change trade policies, including tariffs and threats of additional tariffs that affect certain products which are manufactured in China and mutual exchange of certain types of data. Due to our collaboration with Akeso, we are reliant on collaborating with a company with significant operations in China. We do not know whether and to what extent the Trump administration will in the future implement or alter any tariffs, laws or regulations that may increase the cost or feasibility of importing and exporting products, components and information from China to the United States and vice versa. Further, the effect of any such new tariffs or actions on our industry or customers, and customerswhether they may be subject to any exceptions, is unknown and difficult to predict. As additional tariffs, legislation andor regulations are implemented, or if existing trade agreements are renegotiated, or if China or other affected countries take retaliatory trade actions, such changes could have a material adverse effect on our clinical development plans, business, financial condition, results of operations or cash flows.

The Company'sCompany’s current lead development candidate is ivonescimab, a novel, potential first-in-class bispecific antibody intending to combine the effects of immunotherapy via a blockade of PD-1 with the anti-angiogenesis effects of an anti-VEGF compound into a single molecule. On December 5, 2022, the Company entered into a Collaboration andthe License Agreement (the “License Agreement”) with Akeso, Inc. and its affiliates (collectively, “Akeso”) pursuant to which the Company has in-licensed intellectual property rights related to ivonescimab.ivonescimab (as amended, the “License Agreement”). Through the License Agreement, the Company obtained the rights to develop and commercialize ivonescimab in the United States, Canada, Europe, and Japan. The License Agreement and transaction closed in January 2023 following customary waiting periods. On June 3, 2024, the Company entered into an amendment to the LicenseSecond AgreementAmendment with Akeso to expand its territories covered under the License Agreement to also include the Latin America, including Mexico and all countries in Central America and South America, the Middle East and Africa regions (collectively, and as expanded, the "Licensed Territory").Africa. The Company’s operations are focused on the development of ivonescimab and other future activities, as the Company determines.

The Company hasis begun its development fordeveloping ivonescimab in non-smallNSCLC celland lung cancer (“NSCLC”),CRC, specifically launchingconducting Phase III clinical trials in the following proposed indications:

(a) ivonescimab combined with chemotherapy in patients with epidermal growth factor receptor (“EGFR”)-mutated,EGFR-mutated, locally advanced or metastatic non-squamous NSCLC who havewere progressedpreviously after treatmenttreated with a third-generation EGFR tyrosine kinase inhibitor (“TKI”) (“HARMONi”); and (b) ivonescimab combined with chemotherapy in first-line metastatic NSCLC patients (“HARMONi-3”) In addition, the Company has begun to activate clinical trial sites in the United States for a Phase III clinical study in the following proposed indication:

(cb) ivonescimab monotherapycombined with chemotherapy in patients with first-line metastatic NSCLC (including separate statistical analyses planned for patients with highsquamous PD-L1NSCLC expressionand non-squamous NSCLC) (“HARMONi-7HARMONi-3”).;

Research and Development and Acquired in-process research and development Expenses

Other expense,income, net primarily consists of foreign currency net gains and losses and investment income related to investments in money market funds and U.S. treasury securities. All highly liquid investments with a maturity date of 90 days or less at the date of purchase are considered to be cash equivalents and the related investment income is recognized in net loss. The appropriate classification of investments in securities is determined by the Company at the time of purchase.

Research and Development and Acquired in-process research and development Expenses

The table below summarizes our research and development and acquired in-process research and development expenses by category for the year ended December 31, 20242025 and 2023,2024, respectively.

The entry into the License Agreement with Akeso, Inc., effective in January 2023, represents a significant change in our strategy from anti-infectives to the therapeutic area of oncology. We invested our resources in the clinical development of ivonescimab duringin the yearsperiods ended December 31, 2024 and 2023.presented.

Research and development expenses (excluding acquired in progress research and development noted below) increased by $91.4$371.9 million during the year ended December 31, 2024,2025, compared to the same period in the prior year. This increase was primarilyin part due to the increase in stock-based compensation expense of $202.6 million for the year ended December 31, 2025, as a result of the modification to our performance-based stock option awards during the second quarter of 2025. In addition, our continued investment in oncology clinical trial related costsexpenses for ivonescimab, known as SMT112 in theour Licensed Territory, resultingresulted in an increase of $65.7$165.5 million and an increase in compensation and stock-based compensation related expenses of $23.9 million infor the year ended December 31, 2024,2025, primarily due to supportadding thenew clinical developmenttrials ofand ivonescimabexpanding as we continue to hire additionalcurrent clinical resourcestrials infrom thelast oncology field, coupled with acceleration charges related to the achievement of certain market conditions on performance stock option awards.year. We expect oncology-related research and development costs to continue to increase as we progress with the development of ivonescimab.

General and administrative expenses increased by $30.2$496.5 million for the year ended December 31, 2024,2025, compared to the same period in the prior year,year. The increase was primarily due to anthe increase of $25.3 million in stock-based compensation relatedexpense of $478.8 million for the year ended December 31, 2025, as a result of the modification to anour increase in equity award grants and the acceleration charges related to the achievement of certain market conditions on performanceperformance-based stock option awards.awards Additionally,during compensation-relatedthe second quarter of 2025. In addition, compensation related costs, excluding stock-based compensationcompensation, increased by $4.6$8.2 million, for the year ended December 31, 2024,2025, compared to the same period in the prior year, as the Company is focused on building its executive management team and legal fees and professional services increased by $6.4 million for the year ended December 31, 2025, compared to the same period in the prior year to continue supporting itsthe growth.development of ivonescimab. We expect general and administrative expenses to continue to increase as we scale our infrastructure and management to support development of ivonescimab.

Other Income (Expense),Income, Net

The table below summarizes our other income (expense),income, net by category for the year ended December 31, 20242025 and 2023,2024, respectively.

Other income (expense),income, net increased by $2.2$1.4 million for the year ended December 31, 2024,2025, compared to the same period in the prior year, primarily due to an increase of $3.0$2.0 million in interest income due to the higher cash equivalents and short-term investments balance, partially offset by unfavorable changes in foreign currency losses of $0.7 million.balance.

Interest expense on promissory notes payable to related parties decreased to $8.7 million for the year ending December 31, 2024,2025 fromcompared $16.5 million duringto the yearsame endingperiod Decemberin 31,the 2023,prior year, due to the repayment in full paymentof ofthe promissory note in October 2024.

To date, we have financed our operations primarily through issuances of our common stock, including our most recent private placementplacements issued in October 2025 and September 2024 for gross proceeds of $500.0 million and $235.0 millionmillion, respectively, and the raise of $44.2$150.7 million gross proceeds from our ATM Agreement duringsince 2024,inception, issuance of debt, and receipt of payments to us under license and collaboration arrangements.

•invest in clinical development of ivonescimab in theour Licensed Territory;

During the year ended December 31, 2024,2025, we incurred a net loss of $221.3$1,079.6 million, and cash flows used in operating activities was $142.1$322.9 million. As of December 31, 20242025 we had an accumulated deficit of $1,214.6$2,294.2 million, cash and cash equivalents and short-term investments in U.S. treasury securities of $412.3$713.4 million. We expect to continue to generate operating losses for the foreseeable future.

From time to time, we may raise additional equity or debt capital through both registered offerings off of a shelf registration, including “at-the-market”ATM offerings, and private offerings of securities. On February 20, 2024, we filed a shelf registration statement on Form S-3 with the SEC, which the SEC declared effective on February 27, 2024. Through our shelf registration statement we may, from time to time, sell up to an aggregate of $450$450.0 million of our common stock, preferred stock, debt securities, depositarydepository shares, warrants, subscription rights, purchase contracts, or units. Of the $450$450.0 million of liquidity available to us under this shelf registration statement, on May 13, 2024, we had established an at-the-marketATM offering program with J.P. Morgan Securities LLC, as sales agent, in the amount of up to $90$90.0 million, of which $45.8 million remains available for sale as of December 31, 2024. If we require or elect to seek additional capital through debt or equity financing in the future, we may not be able to raise capital on terms acceptable to us or at all. To the extent we raise additional capital through the sale of equity or convertible debt securities, the issuance of such securities will result in dilution to our stockholders. If we are required and unable to raise additional capital when desired, our business, operating results and financial condition may be adversely affected. As of the date of this report, additional capital has not been secured.million.

If we are unable to raise additional funds through equity or debt financings or other arrangements when needed, we may be required to delay, limit, reduce or terminate our product development or future commercialization efforts or grant rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves, which could materially adversely affect our businessbusiness, prospectsoperating orresults and financial condition and our ability to continue operations.

The following table summarizes the results of our cash flows for the years ended December 31, 20242025 and 2023.2024.

Net cash used in operating activities for the year ended December 31, 20242025 was $142.1$322.9 million and primarily resultedconsisted from aof net loss of $221.3 million, which included an adjustment of $15.0$1,079.6 million and a $31.4 million net change in cashoperating payments related to investing activities for the purchase of in-process researchassets and developmentliabilities, frompartially Akesooffset under the terms of the License Agreement and the associated direct transaction costs,by non-cash charges of $48.7 million and a net increase in working capital of $15.5$725.2 million. Non-cashThe non-cash charges primarily includeconsisted $51.0of $732.4 million of stock-based compensation,compensation driven by the modification to outstanding performance-based stock option awards which removed the performance-based vesting criteria, partially offset by $2.6$7.0 million relatedrelating to the amortization of the discount on short-term investments.investments in U.S. Treasury securities. The net increasechange in working capital is primarily due to ana $11.9$15.3 million increase in accounts payable, a $12.9 million increase in accrued liabilities and other current liabilities, a $6.6 million increase in accrued compensation, a $2.5$4.9 million decrease in other assets, and a $2.0 million increase in accounts payable, partially offset by a $7.9 million increase in prepaid expenses and other current assets, a $2.9 million increase in accrued compensation, partially offset by a $4.9 million increase in other assets.

Net cash used in operating activities for the year ended December 31, 20232024 was $76.8$142.1 million and primarily resulted from a net loss of $614.9$221.3 million, which included an adjustment of $475.0$15.0 million in cash payments related to investing activities for the purchase of in-process research and development from Akeso under the terms of the License Agreement and the associated direct transaction costs andcosts, non-cash charges of $63.6$48.7 million and a net decreasechange in workingoperating capitalassets and liabilities of $0.5$15.5 million. Non-cash charges primarily include a $45.9 million expense for the issuance of shares in lieu of cash for the Akeso upfront payment, $14.1$51.0 million of stock-based compensation, $6.3partially offset by $2.6 million related to non-cash interest expense, and a $0.5 million impairment charge, partially offset by $1.9 million related tothe amortization of discount on short-term investments and $0.8 million in a net unrealized foreign exchange gain.investments. The net increasechange in workingoperating capitalassets and liabilities is primarily due to aan $3.7$11.9 million increase in accrued liabilities and other long-termcurrent assets,liabilities, a $2.4$6.6 million increase in accrued compensation, a $2.5 million decrease in accruedother liabilities,assets, and a $0.4$2.0 million decreaseincrease in leaseaccounts liabilities,payable, partially offset by a $4.2 million decrease in the research and development tax credit receivable and a $2.3$7.4 million increase in accountsprepaid payable.expenses and other current assets.

Net cash used in investing activities for the years ended December 31, 2024 was $205.3 million and was primarily due to $190.2 million of net purchases of short-term investments and $15.0 million of cash payments made to Akeso pursuant to the License Agreement. Net cash used in investing activities for the years ended December 31, 2023 was $587.8 million and was primarily due to $475.0 million of cash payments made to Akeso pursuant to the License Agreement and $112.9 million of net purchases of short-term investments.

Furthermore, on January 19, 2023, we and Mr. Duggan rectified the Duggan February Note and Duggan September Note in order to correctly reflect the parties’ intent that we may only prepay (i) the Duggan February Note following the completion of a public rights offering to be conducted by us in the approximate amount of $500 million, or a similar capital raise, in an amount equal to the lesser of (x) the net proceeds of the 2023 Rights Offering or such capital raise or (y) the full amount outstanding of the Duggan February Note, and (ii) the Duggan September Note following the completion of a capital raising transaction subsequent to the 2023 Rights Offering (as defined in Note 17 Stockholders’ Equity to the consolidated financial statements included under Item 15 Exhibits, Financial Statement Schedules) in an amount equal to the lesser of (A) the net proceeds of such capital raise or (B) the full amount outstanding of the Duggan September Note. Following the issuance of the two new Promissory Notes (the “Duggan Promissory Notes”), the Duggan February Note and Duggan September Note were marked as “cancelled” on their face and replaced in their entirety by the Duggan Promissory Notes (together with the Zanganeh Note, the “Notes”). The Notes accrued interest at an initial rate of 7.5%. All interest on the Notes was paid on the date of signing for the period through February 15, 2023. Such prepaid interest was paid in a number of shares of our common stock, par value $0.01 (“Common Stock”) equal to the dollar amount of such prepaid interest, divided by $0.7913 (the consolidated closing bid price immediately preceding the time we entered into the Note Purchase Agreement, plus $.01), which was 9,720,291 shares. For all applicable periods following February 15, 2023, interest accrued on the outstanding principal balance of the Notes at the US prime interest rate, as reported in the Wall Street Journal, plus 50 basis points, as adjusted monthly, for three months immediately following February 15, 2023, and thereafter at the US prime rate plus 300 basis points, as adjusted monthly. Accrued interest was paid in cash, quarterly in arrears, on each of March 31, June 30, September 30 and December 31.

On February 15, 2023, the $20 million Zanganeh Note matured and we repaid the outstanding principal balance. In connection with the closing of the 2023 Rights Offering, the $400 million Duggan Promissory Note matured and became due, and we satisfied all principal and accrued interest thereunder using a combination of a portion of the cash proceeds from the 2023 Rights Offering and the extinguishment of a portion of the amount due equal to the subscription price of shares subscribed by Mr. Duggan in the 2023 Rights Offering.

Our unaudited financial statements have been prepared under the assumption that we would continue as a going concern. However, we have concluded that there is substantial doubt about our ability to continue as a going concern, because without additional sources of funding, our cash and cash equivalents and short-term investments at MarchJune 31,30, 2026 are not sufficient for us to fund our working capital needs for the next twelve months after the date that the unaudited financial statements included in this Quarterly Report on Form 10-Q are issued. Management’s plans concerning these matters, including raising additional capital, are described in Part I - Item 2 – Management’s Discussion and Analysis of Financial Condition and Results of Operation - Liquidity and Capital Resources – Sources of Liquidity of our unaudited financial statements included within this Quarterly Report on Form 10-Q. We continue to evaluate options to further finance our operating cash needs for our product candidates through a combination of some, or all, of the following: equity and debt offerings, collaborations, strategic alliances, grants and clinical trial support from government entities, philanthropic, non-government and not-for-profit organizations, and marketing, distribution or licensing arrangements. However, we cannot guarantee that we will be able to obtain any or sufficient additional funding or that such funding, if available, will be obtainable on terms satisfactory to us. If we are unable to raise capital in the near term or on attractive terms, we could be forced to delay or reduce our research and development programs or any future commercialization efforts, or even curtail or cease operations.

Patient enrollment was completed for the squamous cohort of HARMONi-3 in the first quarter of 2026. Previously, Summit announced its intention to perform an interim PFS analysis for the squamous cohort of the HARMONi-3 study in the second quarter of 2026 and final PFS analysis in the second half of 2026. To achieve statistical significance, there was a meaningfully higher bar than the upcoming planned final PFS analysis based on the minimal alpha spent on the interim analysis. At this early PFS interim analysis reviewed exclusively by the Independent Data Monitoring Committee (iDMC), the iDMC recommended that the study continue as planned. No safety concerns were noted, and the study continues to be double-blinded. ThereThe number of PFS events needed in the squamous cohort for the primary analysis is no changeexpected to thebe previously guided timing of the preplanned final PFS analysisreached in the second half of 2026.2026, and a planned early interim analysis for OS is expected to take place in conjunction with the primary PFS analysis. An interim analysis for overall survival independent of PFS is planned for the first half of 2027.

Enrollment in the non-squamous cohort of the global HARMONi-3 isstudy expectedwas tocompleted complete by the end ofin the second quarter of 2026. TheFor Companythis expectscohort, the number of events needed to performconduct the PFS analysis foris thisexpected cohortto be reached in the first half of 2027. Interim analyses for OS are planned to be conducted, based upon reaching prespecified numbers of events.

In June 2025, the Company entered into a clinical trial collaboration with Revolution Medicines Inc. (“RevMed”) to evaluate ivonescimab in combination with three RevMed RAS(ON) inhibitors (the “RevMed Collaboration”). In January 2026, the Company entered into a clinical trial collaboration with GSK plc to evaluate ivonescimab in combination with GSK’s novel B7-H3,B7-H3 ADC, risvutatug rezetecan, in multiple solid tumors (the “GSK Collaboration”). Neither the RevMed Collaboration nor the GSK Collaboration include upfront payments, milestone payments, or royalty sharing provisions. For the three and six months ended MarchJune 31,30, 2026, there was no cash consideration exchanged in connection with either the RevMed Collaboration or the GSK Collaboration.

Patient enrollment was completed for the squamous cohort of HARMONi-3 in the first quarter of 2026. Previously, Summit announced its intention to perform an interim PFS analysis for the squamous cohort of the HARMONi-3 study in the second quarter of 2026 and final PFS analysis in the second half of 2026. To achieve statistical significance, there was a meaningfully higher bar than the upcoming planned final PFS analysis based on the minimal alpha spent on the interim analysis. At this early PFS interim analysis reviewed exclusively by the Independent Data Monitoring Committee (iDMC), the iDMC recommended that the study continue as planned. No safety concerns were noted, and the study continues to be double-blinded. ThereThe number of PFS events needed in the squamous cohort for the primary analysis is no changeexpected to thebe previously guided timing of the preplanned final PFS analysisreached in the second half of 2026.2026, and a planned early interim analysis for OS is expected to take place in conjunction with the primary PFS analysis. An interim analysis for overall survival independent of PFS is planned for the first half of 2027.

Enrollment in the non-squamous cohort of the global HARMONi-3 isstudy expectedwas tocompleted complete by the end ofin the second quarter of 2026. TheFor Companythis expectscohort, the number of events needed to performconduct the PFS analysis foris thisexpected cohortto be reached in the first half of 2027. Interim analyses for OS are planned to be conducted, based upon reaching prespecified numbers of events.

In the first quarter of 2026, the Company announced that GORTEC (Groupe d'Oncologie Radiothérapie Tête Et Cou or Head and Neck Oncology and Radiotherapy Group), a cooperative group dedicated to Head and Neck Oncology, will initiate the Phase III clinical study, ILLUMINE (NCT07264075), which will evaluate ivonescimab monotherapy and ivonescimab in combination with ligufalimab, Akeso’s proprietary anti-CD47 monoclonal antibody, against monotherapy pembrolizumab in a three-arm study. The study is intended to be conducted in multiple countries in Europe and in China; Summit will consider the expansion of this study into the United States. The primary endpoint for the study is OS. The study, currently planned to enroll 780 patients with recurrent or metastatic PD-L1 positive head and neck squamous cell carcinoma (HNSCC), is expected to beginbegan enrollment in the second quarter of 2026. Data supporting this study was previously presented at the 2024 European Society for Medical Oncology Annual Congress (“ESMO 2024”), whereby ivonescimab in combination with ligufalimab demonstrated an objective response rate of 60% in 20 patients with a median PFS of 7.1 months after a median follow-up time of 4.1 months; OS was not mature at the time of this analysis. At the time of data cut-off for this presentation, no patients receiving ivonescimab plus ligufalimab permanently discontinued drug treatment due to treatment-related adverse events.

In the fourth quarter of 2023, we began collaborating with multiple institutions globally and opened our investigator- sponsored trials program across several disease areas. We continued to expand this program in 2024 and 2025 in order to discover additional opportunities for ivonescimab, including in several tumors outside of our current development plan.

After announcing positive qualitative results for the HARMONi-6 trial, on April 23, 2025, detailed clinical trial results of the study were presented as part of the Presidential Symposium at the European Society for Medical Oncology’s 2025 Congress (“ESMO 2025”). OverallAdditionally, positive overall survival data from the HARMONi-6 trial is planned to bewas presented on May 31, 2026 as a late breaking abstract for the plenary session at the ASCO 2026 Annual Meeting. The HARMONi-6 study evaluated ivonescimab in combination with platinum-based chemotherapy compared to tislelizumab (a PD-1 inhibitor) in combination with platinum-based chemotherapy in patients with previously untreated advanced NSCLC irrespective of PD-L1 expression. HARMONi-6, also referred to as AK112-306, is a single region, multi-center, double-blinded Phase III study conducted in China sponsored by Akeso, with all relevant data exclusively generated, managed, and analyzed by Akeso.

In the HARMONi-6 planned PFS interim analysis, ivonescimab in combination with chemotherapy demonstrated a statistically significant improvement in the primary endpoint, PFS, by IRRC, when compared to tislelizumab in combination with chemotherapy, achieving a hazard ratio of 0.60 (95% CI: 0.46, 0.78; p<0.0001). AIn the HARMONi-6 planned interim analysis of OS, ivonescimab in combination with chemotherapy demonstrated a statistically significant improvement when compared to tislelizumab in combination with chemotherapy, with a hazard ratio of 0.66 (95% CI: 0.50, 0.87; p=0.0017). For both PFS and OS, a clinically meaningful benefit was demonstrated across clinical subgroups, including those with either PD-L1 negative or positive expression, as well as high-risk patients. OS data was not yet mature at the time of the data cutoff and is planned to be evaluated in the future.expression.

Ivonescimab demonstrated an acceptable and manageable safety profile in the HARMONi-6 study, which was consistent with previous Phase III studies conducted studying ivonescimab. Nine14 patients (3.4%5.3%) discontinued ivonescimab plus chemotherapy due to TRAEs compared to 1112 patients (4.2%4.5%) receiving tislelizumab plus chemotherapy due to TRAEs. There were eight10 patients in the ivonescimab plus chemotherapy arm and 1011 patients in the tislelizumab plus chemotherapy arm who died as a result of TRAEs in this Phase III study. Results were published in Lancet (ChenLu et al. 20252026).

The following table sets forth our results of operations for the three and six months ended MarchJune 31,30, 2026 and 2025:

The table below summarizes our research and development expenses by category for the three and six months ended MarchJune 31,30, 2026 and 2025, respectively.

Research and development expenses increaseddecreased by $81.4$50.3 million during the three months ended MarchJune 31,30, 2026 and increased $31.0 million during the six months ended June 30, 2026, respectively, compared to the same periodperiods in the prior year. The increase in third-party research and development expenses for the three and six months ended June 30, 2026, was primarily driven by a $31.5$36.9 million and $68.4 million increase in clinical trial related expenses, respectively, a $19.9$6.3 million and $26.2 million increase in expenses related to manufacturing and purchasing of clinical trial related materials as a result of increased enrollment in our HARMONi-3, HARMONi-7, and HARMONi-GI3 trials, respectively, and a $2.5$3.3 million and $5.7 million increase in other external research and development expenses.expenses, respectively. The increasedecrease in internal research and development expenses for the three and six months ended June 30, 2026, was primarily driven by a $20.3$104.5 million increaseand $84.2 million decrease in stock-based compensation expense respectively, as a result of the modification to our performance-based stock option awards during the second quarter of 20252025, which is offset by a $7.7 million and a $7.2$14.9 million increase in compensation related costs, excluding stock-based compensation, respectively, as we continue to hire additional resources to support the clinical development of ivonescimab. We expect research and development expenses to continue to increase as we progress with the development of ivonescimab.

The table below summarizes our general and administrative expenses by category for the three and six months ended MarchJune 31,30, 2026 and 2025, respectively.

General and administrative expenses increaseddecreased by $47.0$297.6 million and $250.6 million for the three and six months ended MarchJune 31,30, 2026,2026 respectively, compared to the same periodperiods in the prior year. The increasedecrease was primarily driven by a $41.4$305.6 million increaseand $264.2 million decrease in stock-based compensation respectively, as a result of the modification to our performance-based stock option awards during the second quarter of 2025. In addition, compensation related costs, excluding stock-based compensation, increased by $3.4$3.5 million and $6.9 million for the three and six months ended MarchJune 31,30, 2026 respectively, compared to the same periodperiods in the prior year asdue theto Companyincreased isheadcount. focused on building its executive management team, andAdditionally, legal fees and professional services increased by $1.8$3.3 million and $5.1 million for the three and six months ended MarchJune 31,30, 2026 respectively, compared to the same periodperiods in the prior year to continue supporting the development of ivonescimab. We expect general and administrative expenses to continue to increase as we scale our infrastructure and managementincrease teamour headcount to support the development of ivonescimab.

The table below summarizes our other income by category for the three and six months ended MarchJune 31,30, 2026 and 2025, respectively.

For the three and six months ended MarchJune 31,30, 2026, other income, net increased by $1.9$2.1 million and $3.9 million, compared to the same periodperiods in the prior year, primarily due to an increase of $2.1$1.4 million and $3.5 million in investment income due to higher cash equivalents and short-term investments balance.balance, respectively.

During the three and six months ended MarchJune 31,30, 2026, we incurred a net loss of $189.4$215.7 million and $405.1 million and cash flows used in operating activities for the threesix months ended MarchJune 31,30, 2026 was $122.3$263.4 million. As of MarchJune 31,30, 2026, we had an accumulated deficit of $2,483.6$2,699.3 million, and cash and cash equivalents of $106.5$419.4 million and short-term investments of $492.2$271.3 million. We expect to continue to generate operating losses for the foreseeable future.

ToAs date,of June 30, 2026, we have financed our operations primarily through issuances of our common stock, including our most recent private placements issued in October 2025 and September 2024 for gross proceeds of $500.0 million and $235.0 million, respectively, and the raise of $150.7$381.6 million gross proceeds from our ATMDistribution Agreement since inception, issuance of debt, and receipt of payments to us under license and collaboration arrangements. The remaining gross proceeds available under the Distribution Agreement as of June 30, 2026 was approximately $68.4 million which was utilized subsequent to June 30, 2026.

On August 11, 2025, we entered into the Amendment to the Original Distribution Agreement. Pursuant to the Amendment, the Original Distribution Agreement was amended to, among other things, increase the aggregate offering price of shares of the Company’s common stock, par value $0.01 per share, from time to time, through the sales agent, by up to an additional $360.0 million. The remaining gross proceeds available under the Distribution Agreement as of MarchJune 31,30, 2026 was approximately $299.3$68.4 million.million which was utilized subsequent to June 30, 2026.

The following table summarizes our cash flows for the threesix months ended MarchJune 31,30, 2026 and 2025:

Net cash used in operating activities for the threesix months ended MarchJune 31,30, 2026 was $122.3$263.4 million and primarily consisted of a net loss of $189.4$405.1 million and a $1.7$7.1 million net change in operating assets and liabilities, partially offset by non-cash charges of $68.8$134.6 million. The non-cash charges primarily consisted of $72.8$141.5 million of stock-based compensation driven by the modification to outstanding performance-based stock option awards which removed the performance-based vesting criteria, partially offset by $4.2$7.2 million relating to amortization of the discount on short-term investments in U.S. government treasury bills. The net change in operating assets and liabilities was primarily due to a $12.2$33.0 million increase in accrued liabilities and a $6.8$2.9 million increase in accounts payable, offset by a $11.0$23.0 million increase in prepaid expenses and other current assets, a $7.9$1.2 million increase in other assets, and a $5.5 million decrease in accrued compensation, and a $1.1 million decrease in other current liabilities.compensation.

Net cash used in operating activities for the threesix months ended MarchJune 31,30, 2025 was $61.2$127.9 million and primarily consisted of thea net loss of $62.9$628.6 million and a $6.2$15.2 million net change in operatingworking assets and liabilities,capital, partially offset by non-cash charges of $7.9$485.5 million. The non-cash charges primarily consisted of $11.1$489.9 million of stock-based compensation,compensation driven by the modification to outstanding performance-based stock option awards which removed the performance-based vesting criteria, partially offset by $3.0$4.0 million relating to amortization of the discount on short-term investments in U.S. governmentTreasury treasury bills.securities. The net change in operatingworking assets and liabilitiescapital was primarily due to a $7.6 million decrease in accrued compensation, a $1.4$18.3 million increase in otheraccounts assetspayable and a $1.0$6.5 million decreaseincrease in other currentaccrued liabilities, partially offset by a $1.9$5.4 million decrease in prepaidaccrued expenses and other current assetscompensation and a $1.6$3.7 million increase in accruedother liabilities.assets.

Net cash provided by investing activities for the threesix months ended MarchJune 31,30, 20252026 was $160.1$222.7 million and primarily driven by $160.5$626.1 million received fromin maturities and sales of short-term investments, offset by $402.3 million in purchase of short-term investments and $1.2 million in U.S.purchases governmentof treasuryproperty bills.and equipment.

Net cash provided by financing activities for the threesix months ended MarchJune 31,30, 20252026 was $7.7$234.9 million and was driven by $5.7$227.4 million ofnet proceeds receivedfrom relatedour tocurrent theDistribution exercise of warrantsAgreement and $2.0$7.5 million of proceeds received related to employee stock awards and purchase plans.