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

We are a clinical-stage biopharmaceutical company with a limited operating history focused on pioneeringdeveloping a novel disease-modifying therapeuticapproach approachtargeting what we believe to treatbe a key underlying cause of Alzheimer’s disease, or AD. We were incorporated in 1996 and were party to an exclusive license and research collaboration with Merck & Co., Inc., or Merck, in 2003. Although we acquired the exclusive rights to sabirnetug from Merck in 2011, following Merck’s strategic decision to focus its AD development efforts on a different product candidate, we did not recommence meaningful operations until we completed our first institutional fundraising in 2018. As a result, we have a very limited operating history, which may make it difficult to evaluate the success of our business to date and to assess our future viability. Drug development is a highly uncertain undertaking and involves a substantial degree of risk. We received clearanceauthorization of our Investigational New Drug application, or IND, for our sole product candidate, sabirnetug, and initiated our Phase 1 clinical trial in the second quarter of 2021. In October 2021, we announced the initial dosing of the first patient in the INTERCEPT-AD trial and in February 2023 we announced the completion of enrollment. We announced topline data from INTERCEPT-AD in July 2023. We initiated our Phase 2 clinical trial, ALTITUDE-AD, in May 2024 and2024, completed enrollment in March 2025.2025 and expect to announce top-line results in late 2026. We also conducted a Phase 1 clinical trial investigating a subcutaneous dosing option of sabirnetug in mid-2024 and announced results in March 2025. In addition, we announced a collaboration with JCR Pharmaceuticals Co. Ltd., or JCR, in July 2025, pursuant to which we are conducting preclinical studies, in coordination with JCR, to assess a blood-brain barrier-penetrating, Aß oligomer-targeted Enhanced Brain Delivery (EBD™) therapy for the treatment of AD. We have previously experienced delays in site activation and enrollment with respect to our INTERCEPT-AD clinical trial, and cannot assure you that we will not experience additional delays in site activation or enrollment in our current or future clinical trials. To date, we have not yet initiated a pivotal trial, obtained marketing approval for any product candidate, manufactured a commercial scale product candidate, arranged for a third party to do so on our behalf or conducted sales or marketing activities necessary for successful product candidate commercialization. Our short operating history makes any assessment of our future success and viability subject to significant uncertainty. We will likely encounter risks and difficulties frequently experienced by early-stage biopharmaceutical companies in rapidly evolving fields, and we have not yet demonstrated an ability to overcome such risks and difficulties successfully. If we do not address these risks and difficulties successfully, our business will suffer.

We will require substantial additional funding to finance our operations, complete the development and commercialization of sabirnetug for AD and evaluate future product candidates.candidates, including any Aß oligomer-targeted EBD™ product candidates we may develop pursuant to our collaboration with JCR. If we are unable to raise thisadditional funding when needed, we may be forced to delay, reduce or eliminate our drug development programs or other operations.

To date, we have used substantial amounts of cash to fund our operations, and we expect our expenses to increase substantially in the foreseeable future in connection with our ongoing activities, particularly as we continue the research and development, conduct clinical trials of, and seek marketing approval for, sabirnetug.sabirnetug and any future product candidates we may develop. Developing sabirnetug and conducting clinical trials for the treatment of AD and any other product candidates or indications that we may pursue in the future will require substantial amounts of capital. In addition, if we obtain marketing approval for sabirnetug or any future product candidates, we expect to incur significant commercialization expenses related to the commercialization of the product, whether we are commercializing alone or with a collaborator. Further, we expect to incur significant expenses associated with operating as a public company.

Accordingly, we will need to obtain substantial additional funding in connection with our continuing operations. As of December 31, 2024,2025, we had $35.6$54.0 million in cash and cash equivalents and $195.9$62.9 million in marketable securities; included in this amount is the first tranche of $30.0 million that we received under our loan and security agreement with K2 HealthVentures LLC, or the Loan Agreement, which was received on November 10, 2023.securities. Based on our current operating plan, we believe that our existing cash and cash equivalents and marketable securities will be sufficient to enable us to fund our operating expenses and capital expenditure requirements into the first half ofearly 2027. In addition, changing circumstances may cause us to increase our spending significantly faster than we currently anticipate, and we may need to spend more money than currently expected because of circumstances beyond our control. We may need to raise additional funds sooner than anticipated if we choose to expand more rapidly than we presently anticipate.

•the progress, costs, timing and results of ALTITUDE-AD and other potential clinical trials of sabirnetug,sabirnetug includingand/or preclinical trials related to the potential development of an Aß oligomer-targeted EBDTM therapy, or for any potential additional indications that we may pursue beyond AD;

We are early in our development efforts. To date, we have invested substantially all of our efforts and financial resources in the research and development and clinical trials of sabirnetug, which is currently our only product candidate. Before seeking marketing approval from regulatory authorities for the sale of sabirnetug, or any other product candidate we may develop, we must conduct extensive clinical trials to demonstrate the safety and efficacy of the drug in humans. We are not permitted to market or promote any product candidate before we receive regulatory approval from the FDA, or comparable foreign regulatory authorities, and we may never receive such regulatory approval. We cannot be certain that sabirnetug will be successful in clinical trials. Further, sabirnetug may not receive regulatory approval even if it is successful in clinical trials. If we do not receive regulatory approvals for sabirnetug, we may not be able to continue our operations. Our prospects, including our ability to finance our operations and generate revenue, will depend entirely on the successful development, regulatory approval and commercialization of sabirnetug by us or by one or more of our partners. The clinical and commercial success of sabirnetug will depend on a number of factors, including the following:

•successful patientcompletion enrollment inof ALTITUDE-AD and other clinical trials of sabirnetug;

•whether we are required by the FDA, EMA or other regulatory authorities to conduct additional clinical trials prior to the approval to market sabirnetug and whether the FDA, EMA or other regulatory authorities may disagree with the number, design, endpoints, size, conduct, implementation or other aspects of our clinical trials;

Our future success is highly dependent on the successful development of sabirnetug for treating AD. The development and, if approved, commercialization of sabirnetug subjects us to a number of challenges, including ensuring that we select an effective dose and delivery mechanism of sabirnetug, executing appropriate clinical trials to test for safety and efficacy and obtaining regulatory approval from the FDA and other regulatory authorities. We cannot be sure that sabirnetug, or any other product candidate we develop, will ultimately prove to be safe and effective, scalable or profitable. Moreover, public perception of drug safety issues, including adoption of new therapeutics or novel approaches to treatment, may adversely influence the willingness of subjects to participate in clinical trials, or if approved, the willingness of physicians to prescribe novel treatments.

In addition, although we have had limited interactions with the FDA and have received important feedback on the design of ALTITUDE-AD from the FDA, we have had limited interactions with the FDA overall; similarly, based on regulatory feedback from the EMA and to enhance the probability that the EMA will consider our Phase 2 clinical trial a registration-eligible clinical trial for sabirnetug, we amended the ALTITUDE-AD protocol in 2024 to change from a Phase 2/3 clinical trial to a Phase 2 standalone clinical trial. However, we cannot be certain how many clinical trials of sabirnetug will be required or how such trials will be designed. Consequently, we may be unable to successfully and efficiently execute and complete necessary clinical trials in a way that leads to submission of a BLA or request for marketing authorization and approval of sabirnetug or any other product candidate. We may require more time and incur greater costs than our competitors and we may not succeed in obtaining regulatory approvals of product candidates that we develop. Failure to commence or complete, or delays in, our planned clinical trials, could prevent us from or delay us in commercializing sabirnetug or any future product candidates we may develop, and failure to successfully complete any of these activities in a timely manner could have a material adverse impact on our business and financial performance.

•the policies, regulations, and guidelines of the FDA, EMA or other comparable foreign regulatory authorities regarding the development, approval and marketing of biologics may significantly change, including but not limited to, in the United States, as a result of the 2025 change in presidential administration, which may hinder our development or commercialization of sabirnetug or future product candidates.

Trials may be subject to delays as a result of patient enrollment taking longer than anticipated or patient withdrawal. We may not be able to initiate or continue clinical trials for our product candidates if we are unable to locate and enroll a sufficient number of eligible patients to participate in these trials as required by the FDA or comparable foreign regulatory authorities. Throughout 2022, we experienced delays in clinical site initiation and patient enrollment that we believe were principally related to the effects of the COVID-19 pandemic. Although those enrollment delays were resolved, including through the addition of new clinical trial sites, and we did not experience enrollment delays with respect to our ALTITUDE-AD clinical trial, we may experience other enrollment delays in the future. We cannot predict how successful we will be at enrolling subjects in future clinical trials. Subject enrollment is affected by other factors including:

We may in the future choose to conduct one or more of our clinical trials outside the United States, including in Europe. The acceptance of study data from clinical trials conducted outside the United States or another jurisdiction by the FDA, EMA or applicable foreign regulatory authorities may be subject to certain conditions or may not be accepted at all. In cases where data from foreign clinical trials are intended to serve as the basis for marketing approval in the United States, the FDA will generally not approve the application on the basis of foreign data alone unless (i) the data are applicable to the United States population and United States medical practice; and (ii) the trials were performed by clinical investigators of recognized competence and pursuant to current good clinical practice, or cGCP, regulations. Additionally, the FDA’s clinical trial requirements, including sufficient size of patient populations and statistical powering, must be met. Many foreign regulatory bodies have similar approval requirements. In addition, such foreign trials would be subject to the applicable local laws of the foreign jurisdictions where the trials are conducted. There can be no assurance that the FDA, EMA or any other comparable foreign regulatory authority will accept data from trials conducted outside of the United States or the applicable jurisdiction. If the FDA, EMA or any applicable foreign regulatory authority does not accept such data, it would result in the need for additional trials, which would be costly and time-consuming and delay aspects of our business plan, and which may result in our product candidates not receiving approval or clearanceauthorization for commercialization in the applicable jurisdiction.

Due to the recent change in U.S. presidential administration, weWe face uncertainty regarding potential regulatory developments that may adversely affect our business.

We face uncertainty regarding the potential for changes in the regulatory environment followingapplicable to biopharmaceutical companies in the changeUnited in U.S. presidential administration in January 2025.States. While many of the newcurrent Trumppresidential administration’s proposed policies appear to be focused on deregulation, the new administration and federal government could adopt legislation, regulationregulations or policies that adversely affect our business or create a more challenging and costly environment to pursue the development and commercialization of sabirnetug or any future product candidates we may develop. For example, the federal government, including the FDA, may implement legislative, regulatory or policy changes regarding the standards for approving biologic products that we may be unable to satisfy or regarding the marketing of approved biologics that may limit or prohibit the advertising and promotion of our current or future product candidates, if approved. Additionally, because one objective of the current Trumppresidential administration appearshas undertaken significant efforts to bereduce tothe decreasesize and spending inof the federal government, theincluding FDAthrough could facesignificant staff reductions,reductions of federal employees, which couldhave impacted the FDA’s workforce and may impact the FDA’s ability to engage in routine regulatory and oversight activities and result in delays or limitations on our ability to proceed with clinical development programs and obtain regulatory approvals. It is difficult to predict how future executive actions that may be taken under the current Trumppresidential administration may affect the FDA’s ability to exercise its regulatory authority. If such executive actions impose constraints on the FDA’s ability to engage in routine oversight and product review activities in the normal course, our business may be negatively impacted.

If we are unable to enter into a commercial collaboration or, alternatively, establish internal sales, marketing and distribution capabilities for sabirnetug or any other product candidatecandidate, including any Aß oligomer-targeted EBD™ product candidates we may develop pursuant to our collaboration with JCR, that may receive regulatory approval, we may not be successful in commercializing those product candidates if and when they are approved.

Our projections of the number of people who have AD, as well as the subset of people with AD who have the potential to benefit from treatment with sabirnetug, are estimates based on our knowledge and understanding of the disease. These estimates may prove to be incorrect and new studies may further reduce the estimated incidence or prevalence of the disease or narrow the universe of patients who would be understoodexpected to potentially benefit for treatment with sabirnetug, if approved. The number of patients in the United States, the European Union and elsewhere may turn out to be lower than expected, may not be otherwise amenable to treatment with our product candidates or patients may become increasingly difficult to identify and access, all of which would adversely affect our business, financial condition, results of operations and prospects. Further, even if we obtain approval for sabirnetug, the FDA or other regulators may limit their approved indications to more narrow uses or subpopulations within the populations for which we are targeting development of sabirnetug.

If approved, sabirnetug will compete with therapies currently approved for the treatment of AD, which have primarily been developed to treat the symptoms of AD rather than the underlying cause of the disease, such as memantine and cholinesterase inhibitors. Sabirnetug may also compete with one or more potentially disease-modifying therapeutics that target Aß or amyloid plaques, including Eisai Co., Ltd.’s, or Eisai’s, Leqembi (lecanemab), which was given full approval by the FDA in July 2023. Also in July 2023, Centers for Medicare and Medicaid Services, or CMS, announced it would cover Leqembi when a physician and care team participates in a CMS-facilitated registry. In August 2025, the FDA approved once-weekly subcutaneous maintenance dosing of Leqembi in patients with early AD following an 18-month intravenous induction period. Moreover, in January 2026, Eisai and Biogen Inc., or Biogen, haveannounced submitted a BLA tothat the FDA granted priority review for a subcutaneous weeklystarting dosing optiondose of Leqembi,Leqembi with a Prescription Drug User Fee Act date inof AugustMay 2025.24, 2026. The FDA issued a complete response letter to Eli Lilly and Company, or Eli Lilly, in January 2023 for the accelerated approval submission of donanemab. In May 2023, Eli Lilly announced results from its donanemab Phase 3 TRAILBLAZER-ALZ 2 trial. In July 2024, the FDA approved donanemab.

Other companies known to be developing therapies with Aß-, AßO-, and amyloid plaque-related targets include AbbVie Inc., or Abbvie, Alector, Inc., or Alector, Alnylam Pharmaceuticals, Inc., AltPep Corporation, Alzheon, Inc., Alzinova AB, BioArctic AB, Biogen, Bristol-Myers Squibb Company, Cognition Therapeutics, Inc., Denali Therapeutics, Inc., or Denali, Eisai Co,Eisai, Eli Lilly, Grifols, S.A., KalGeneKorsana Pharmaceuticals,Biosciences, Inc., Neurimmune AG, Priavoid GmbH, ProMIS Neurosciences, Inc., Prothena Biosciences, Inc., Roche Holding AG (including Genentech, Inc., its wholly-owned subsidiary), or Roche, Vivoryon Therapeutics N.V. and Wavebreak Therapeutics, Inc. Additionally, sabirnetug, if approved, may also compete with other potential therapies intended to address underlying causes of AD that are being developed by several companies, including AbbVie, AC Immune SA, Alector, Anavex Life Sciences Corp., Annovis Bio, Inc., Athira Pharma, Inc., Biogen, Biohaven Pharmaceuticals, Inc., Cassava Sciences, Inc., Denali, Eisai, Johnson & Johnson (including Janssen Inc.Inc., its wholly-owned subsidiary), H. Lundbeck A/S, Lighthouse Pharmaceuticals, Inc., Roche, and Takeda Pharmaceutical Co. Ltd.

In addition, states are adopting new laws or amending existing laws, requiring attention to frequently changing regulatory requirements. AlmostApproximately 20 other states have now passed comprehensive privacy laws that have taken effect or will come into effect at various times over the next few years. Similar laws have been passed or are being considered in several other states, as well as at the federal and local levels. The evolving patchwork of differing state and federal privacy and data security laws increasesmay increase the cost and complexity of operating our business and increasescould increase our exposure to liability. We will continue to monitor and assess the impact of these state laws, which may impose substantial penalties for violations, impose significant costs for investigations and compliance, and carry significant potential liability for our business.

Outside of the United States, data protection and information security laws, including the E.U. General Data Protection Regulation, or the EU GDPR, which also forms part of the law of England and Wales, Scotland and Northern Ireland by virtue of section 3 of the European Union (Withdrawal) Act 2018 and as amended by the Data Protection, Privacy and Electronic Communications (Amendments etc.) (EU Exit) Regulations 2019 (SI 2019/419), or the UK GDPR, also apply to certain of our operations. The EU GDPR and the UK GDPR impose, among other things, data protection requirements that include strict obligations and restrictions on the ability to collect, analyze and transfer personal data of individuals within the EU and UK, a requirement for prompt notice of data breaches to data subjects and supervisory authorities in certain circumstances, and possible substantial fines for any violations. Companies that must comply with the EU GDPR and the UK GDPR face increased compliance obligations and risk, including more robust regulatory enforcement of data protection requirements and potential fines for noncompliance of up to €20 million (or £17.5 million under the UK GDPR) or 4% of the annual global revenues of the noncompliant company, whichever is greater. The EU GDPR and UK GDPR also impose additional restrictions and obligations in relation to the processing of sensitive categories of personal data, including health data. Moreover, on June 19, 2025 the UK’s Data (Use and Access) Act took effect, which introduces certain amendments to the data protection regime in the UK, and therefore creates divergences between the EU and UK. Other governmental authorities around the world are considering and, in some cases, have enacted, similar privacy and data security laws. Failure to comply with applicable data protection laws and regulations could result in government investigations and/or enforcement actions (which could include substantial civil and/or criminal penalties), private litigation and adverse publicity and could negatively affect our business, financial condition and results of operations.

Although we work to comply with applicable laws and regulations relating to data privacy and security, these requirements are evolving and may be modified, interpreted and applied in an inconsistent manner from one jurisdiction to another and may conflict with one another or other legal obligations with which we must comply. Monitoring, preparing for and complying with the array of privacy and security legal regimes to which we are subject also requires us to devote significant resources, including, without limitation, financial and time-related resources. Moreover, many of the laws and regulations in this area are relatively new and their interpretations are uncertain and subject to change. Combined with the frequency with which new privacy and security laws are introduced globally, this means that we may be required to make changes to our operations or practices in an effort to comply with them. Such changes may increase our costsoperating and reduce our net sales.costs. We may also face inconsistent legal requirements across the various jurisdictions in which we operate, further raising both costs of compliance and likelihood that we will fail to satisfy all of our legal requirements. Any failure or perceived failure by us or our employees, representatives, contractors, consultants, collaborators, or other third parties to comply with such requirements or adequately address privacy and security concerns, even if unfounded, could result in additional cost and liability to us, damage our reputation, and adversely affect our business and results of operations.

We engage, and intend to engagecontinue to engage, CROs and other third parties to conduct our planned nonclinical studies orand clinical trials, including ALTITUDE-AD and any future clinical trials of sabirnetug,sabirnetug we may pursue, and to monitor and manage data. We expect to continue to rely on third parties, including clinical data management organizations, medical institutions and clinical investigators, in the future. Any of these third parties may terminate their engagements with us in accordance with the applicable contract, whether in the event of an uncured material breach or at any time for convenience. If any of our relationships with these third parties terminate, we may not be able to timely enter into arrangements with alternative third parties or to do so on commercially reasonable terms, if at all. Switching or adding CROs involves substantial cost and requires management’s time and focus. In addition, there is a natural transition period when a new CRO commences work. As a result, delays occur, which can materially impact our ability to meet our desired clinical development timelines. Though we intend to carefully manage our relationships with our CROs, there can be no assurance that we will not encounter challenges or delays in the future or that these delays or challenges will not have a material adverse impact on our business, financial condition and prospects.

•business interruptions resulting from geo-political actions, including war and terrorism, such as the ongoing warwars in Ukraine and Iran and the Israel-Hamas war, or natural disasters, including earthquakes, volcanoes, typhoons, pandemics, epidemics, floods, hurricanes and fires.

If we are unable to obtain and maintain sufficient intellectual property protection for oursabirnetug and any future product candidate,candidates, andincluding any Aß oligomer-targeted EBD™ product candidates, as well as any other proprietary technologies we develop, or if the scope of the intellectual property protection obtained is not sufficiently broad, our competitors could develop and commercialize products similar or identical to ours, and our ability to successfully commercialize our product candidate, and other proprietary technologies if approved, may be adversely affected.

The patent prosecution process is expensive, time-consuming and complex, and we may not be able to file, prosecute or maintain all necessary or desirable patent applications at a reasonable cost or in a timely manner. It is also possible that we will fail to identify patentable aspects of our research and development output before it is too late to obtain patent protection. Although we enter into a non-disclosure and confidentiality agreementsagreement with parties who have access to patentable aspects of our research and development output, such as our employees, corporate collaborators, outside scientific collaborators, CROs, contract manufacturers, consultants, advisors and other third parties, any of these parties may breach such agreements and disclose such output before a patent application is filed, thereby jeopardizing our ability to seek patent protection for such output. In addition, our ability to obtain and maintain valid and enforceable patents depends on whether the differences between our inventions and the prior art allow our inventions to be patentable over the prior art. Further, publications of discoveries in the scientific literature often lag behind the actual discoveries, and patent applications in the United States and other jurisdictions are typically not published until 18 months after filing, or in some cases not at all.

Presently we have intellectual property rights to our product candidate sabirnetug through a license from Merck. We also have an intellectual property license through a license with Northwestern University, or Northwestern, and, if this agreement remains in place, we could be required to pay low single digit royalties to Northwestern in the future. We entered into a single product license agreement with Lonza Sales AG, or Lonza, on November 2, 2022, for non-exclusive access to Lonza’s glutamine synthetase gene expression system known as the GS System®, to use, develop and manufacture sabirnetug. Additionally, we entered into a non-exclusive collaboration and license agreement with Halozyme in November 2023 with respect to the development of a subcutaneous formulation of sabirnetug, and we entered into a collaboration, option and license agreement with JCR in July 2025 to develop an Aß oligomer-targeted EBD™ therapy for AD. Because our program may require the use of additional proprietary rights held by third parties, the growth of our business will likely depend in part on our ability to acquire, in-license or use these proprietary rights. In addition, our product candidate may require specific formulations to work effectively and efficiently and these rights may be held by others. We may be unable to acquire or in-license, on reasonable terms, proprietary rights related to any compositions, formulations, methods of use, processes or other intellectual property rights from third parties that we identify as being necessary for our product candidate. Even if we are able to obtain a license to such proprietary rights, it may be non-exclusive, thereby giving our competitors access to the same technologies licensed to us. In that event, we may be required to expend significant time and resources to develop or license replacement technology.

Our competitors may have filed, and may in the future file, patent applications covering technology similar to ours, and others may have or obtain patents or proprietary rights that could limit our ability to make, use, sell, offer for sale or import our product candidate or future products or impair our competitive position. Numerous third-party U.S. and foreign issued patents and pending patent applications exist in the fields in which we are developing our product candidate. There may be third-party patents or patent applications with claims to materials, formulations, methods of manufacture or methods for treatment related to the use or manufacture of our product candidate. Any such patent application may have priority over one of our patent applications, which could further require us to obtain rights to issued patents covering such technologies. If another party has filed a U.S. patent application on inventions similar to ours, we may have to participate in an interference proceeding declared by the USPTO to determine priority of invention in the United States. The costs of these proceedings could be substantial, and it is possible that such efforts would be unsuccessful if, unbeknownst to us, the other party had independently arrived at the same or similar invention prior to our own invention, resulting in a loss of our U.S. patent position with respect to such inventions. Other countries have similar laws that permit secrecy of patent applications and may be entitled to priority over our applications in such jurisdictions.

•the federal civil monetary penalties laws, which impose civil fines for, among other things, the offering or transfer orof remuneration to a Medicare or state healthcare program beneficiary if the person knows or should know it is likely to influence the beneficiary’s selection of a particular provider, practitioner, or supplier of services reimbursable to Medicare or a state health program, unless an exception applies;

Beyond the ACA, there have been ongoing healthcare reform efforts.efforts, Forincluding example,efforts federal legislation enacted in 2021 eliminated the statutory capfocused on Medicaiddrug Drugpricing Rebateand Programpayment. rebates (currently set at 100% of a drug’s “average manufacturer price”) effective January 1, 2024. As anotherFor example, the Inflation Reduction Act of 2022, or IRA, includes a number of changes intended to address rising prescription drug prices in Medicare Parts B and D. These changes, which have varying implementation dates,changes include caps on Medicare Part D out-of-pocket costs, Medicare Part B and Part D drug price inflation rebates, a new Medicare Part D manufacturer discount drug program (replacing the previous ACA Medicare Part D coverage gap discount program) and a drug price negotiation program for certain high spend Medicare Part B and D drugs.drugs (with negotiated prices for the first set of drugs scheduled to take effect in 2026). The IRA ishas anticipatedhad and will likely continue to have a significant impact on the pharmaceutical industry. TheAdditionally, focuschanges onto healthcareMedicaid reform,effective includingin reform2024 ofeliminated drugthe pricingMedicaid rebate cap, and payment,changes hasto continuedcertain Medicare price reporting requirements for drugs beginning in the2026 wakewill oflikely increase the IRA.administrative Forand example,compliance inburden 2022,for subsequent to the enactment of the IRA, the Biden administration announced its commitment to expanding certain IRA reforms.manufacturers.

Moreover, there has recently been heightened governmental scrutiny over the manner in which manufacturers set prices for their marketed products, which has resulted in several Congressional inquiries, proposed and enacted legislation and executive orders issued by the prior presidential administration designed to, among other things, bring more transparency to product pricing, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for drug products. Individual states in the United States have also become increasingly active in implementing regulations designed to control pharmaceutical product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing. Healthcare reform efforts have been and may continue to be subject to scrutiny, legal challenge and subsequent amendment, creating further uncertainty.

GeneralOther legislativerecent costgovernment control measuresactions may also affect reimbursementprices or payments for ourprescription productdrugs. candidates.For example, the current presidential administration’s recently announced tariff on branded or patented drugs may increase the cost of drug products that are imported from abroad or manufactured using products or materials imported from abroad. The timeline for implementation of this tariff has not yet been finalized. As another example, the Budget Control Act,Act of 2011, as amended, resulted in the imposition of reductions in Medicare (but not Medicaid) payments to providers in 2013 and will remain in effect into 2032 unless additional Congressional action is taken. Any significant spending reductions affecting Medicare, Medicaid or other publicly funded or subsidized health programs that may be implemented and/or any significant taxes or fees that may be imposed on us could have an adverse impact on our results of operations.

Such changes would likely require substantial time and impose significant costs or could reduce the potential commercial value of sabirnetug or other product candidates, which could materially harm our business and our financial results. In addition, delays in receipt of or failure to receive regulatory clearancesauthorizations or approvals for any other products would harm our business, financial condition and results of operations.

Despite the implementation of security measures, our internal computer systems, and those of third parties on which we rely (including our vendors, contractors and other third-party partners who process information on our behalf or have access to our systems), are vulnerable to damage from computer viruses, malware, ransomware, phishing attacks and other forms of social engineering, denial-of-service attacks, business email compromise, third-party or employee theft or misuse and other negligent actions, natural disasters, terrorism, war, telecommunication and electrical failures, cyberattacks or cyber-intrusions, security incidents, disruptions, and persons inside our organization or persons with access to systems inside our organization. The risk of a security breach or disruption, particularly through cyberattacks or cyber intrusion, including by computer hackers, foreign governments and cyber terrorists, has generally increased as the number, intensity and sophistication of attempted attacks and intrusions from around the world have increased. If such an event were to occur and cause interruptions in our operations, it could result in a material disruption of our product development programs. For example, the loss of clinical trial data from completed, ongoing or planned clinical trials could result in delays in our regulatory approval efforts and significantly increase our costs to recover or reproduce the data. To the extent that any disruption or security breach were to result in a loss of or damage to our data or applications, or inappropriate disclosure of confidential or proprietary information, we could incur material legal claims (including class claims) and liability, substantial remediation costs, regulatory enforcement, liability under data protection laws, additional reporting requirements and damage to our reputation, and the further development of our product candidates could be delayed. Further, we cannot be sure that insurance will continue to be available to us on commercially reasonable terms (if at all), or that any insurer will not deny coverage as to any future claim.

The process of building our accounting and financial functions and systems has required and will continue to require significant additional professional fees, internal costs and management efforts. For example, we currently do not have an internal audit group, and we may need to hire additional accounting and financial staff to maintain effective internal control over financial reporting. We currently rely on consultants or external service providers to assist with our financial reporting and certain technical aspects thereof, and to provide services related to our finance function to supplement our internal staff, including with respect to our accounts payable, account reconciliations, and the evaluation and documentation of our system of internal controls functions. Any disruptions or difficulties in maintaining or expanding our internal financial staff or the services provided by outside consultants or financial service providers, or in implementing or using our accounting and financial functions and infrastructure, could adversely affect our system of internal controls and harm our business. Moreover, such disruption or difficulties could result in unanticipated costs and diversion of management attention. In addition, we may discover weaknesses in our system of internal financial and accounting controls and procedures that could result in a material misstatement of our financial statements. Our internal control over financial reporting will not prevent or detect all errors and all fraud. A control system, no matter how well designed and operated, can provide only reasonable, not absolute, assurance that the control system’s objectives will be met. Because of the inherent limitations in all control systems, no evaluation of controls can provide absolute assurance that misstatements due to error or fraud will not occur or that all control issues and instances of fraud will be detected.

Prior to our initial public offering, there was no public market for our common stock. Although our common stock is listed on Nasdaq, an active trading market for our shares may never develop or be sustained. If an active market for our common stock does not develop or is not sustained, it may be difficult for you to sell shares of our common stock at an attractive price or at all. AnA less active or inactive market may also impair our ability to raise capital to continue to fund our operations by selling our common stock and may impair our ability to acquire other companies or technologies by using our common stock as consideration.

Sales of a substantial number of shares of our common stock in the public market, particularly sales by our directors, executive officers and principal stockholders, or the perception that these sales might occur, could depress the market price of our common stock and could impair our ability to raise capital through the sale of additional equity securities. AsWe are unable to predict the timing or effect of Marchsuch 24,sales 2025,on wethe hadmarket 60,573,425 sharesprice of common stock outstanding. All of the shares ofour common stock sold during the initial public offering are currently freely tradable, except for any shares held by our affiliates as defined in Rule 144 under the Securities Act of 1933, or the Securities Act.stock.

We have filed registration statements on Form S-8 under the Securities Act of 1933, as amended, or the Securities Act, registering 15,817,73519,461,572 shares of common stock subject to options or other equity awards issued or reserved for future issuance under our equity incentive plans and plan to file additional registration statements on Form S-8 for additional shares of common stock issuable under our equity incentive plans. Shares registered under these registration statements on Form S-8 can be freely sold in the public market upon issuance, subject to the vesting of the equity awards, other restrictions provided under the terms of the applicable plan or equity award and the restrictions of Rule 144 in the case of our affiliates.

Our management team may use our cash and cash equivalents, including the net proceeds from our initial public offering,equivalents in ways in which you may not agree or in ways which may not yield a return.

Our management has broad discretion over the use of our cash and cash equivalents, including the net proceeds from our initial public offering.equivalents. You will not have the opportunity to influence our decisions on how to use our cash and cash equivalents and will need to rely on our judgment with respect to the use of our cash and cash equivalents. The failure by our management to apply our cash and cash equivalents effectively could adversely affect our ability to continue maintaining and expanding our business.

Disruptions at the FDA and other agencies may also slow the time necessary for new drugs or biologics to be reviewed and approved by necessary government agencies, which would adversely affect our business. For example, over the last several years, including most recently from DecemberOctober 22,1, 20182025 to JanuaryNovember 25,12, 2019,2025, the U.S. government has shut down several times, and certain regulatory agencies, such as the FDA and the SEC, have had to furlough critical FDA, SEC and other government employees and stop critical activities. If a prolonged government shutdown occurs,occurs or if the FDA’s workforce is reduced further, it could significantly impact the ability of the FDA to timely review and process our regulatory submissions, which could have a material adverse effect on our business.

If a prolonged government shutdown occurs, if the U.S. government takes certain personnel actions, or if global health concerns prevent the FDA or other comparable regulatory authorities from conducting business as usual or conducting inspections, reviews or other regulatory activities, it could significantly impact the ability of the FDA to timely review and process our regulatory submissions, which could have a material adverse effect on our business.

Our results of operations could be adversely affected by general conditions in the global economy and in the global financial markets. Portions of our clinical trials may be conducted outside of the United States and unfavorable economic conditions resulting in the weakening of the U.S. dollar would make those clinical trials more costly to operate. Further, a severe or prolonged economic downturn, including a recession or depression resulting from the national or international events or political disruption, such as the ongoing conflict between Russia and UkraineUkraine, the recent military actions involving Iran or the Israel-Hamas war, could result in a variety of risks to our business, including weakened demand for our product candidates or any future product candidates, if approved, and our ability to raise additional capital when needed on acceptable terms, if at all. A weak or declining economy or political disruption, including any international trade disputes, could also strain our manufacturers or suppliers, possibly resulting in supply disruption, or cause our customers to delay making payments for our potential products. Any of the foregoing could seriously harm our business, and we cannot anticipate all of the ways in which the political or economic climate and financial market conditions could seriously harm our business.

We are a clinical-stage biopharmaceutical company developing a novel disease-modifying approach to targettargeting what we believe to be a key underlying cause of Alzheimer’s disease, or AD. Alzheimer’s disease is a progressive neurodegenerative disease of the brain that leads to loss of memory and cognitive functions and ultimately results in death. Our scientific founders pioneered research on soluble amyloid-beta oligomers, or AßOs, which are globular assemblies of the amyloid-beta, or Aß, peptide that are distinct from Aß monomers and amyloid plaques. Based on decades of research and supporting evidence, AßOs have gained increasing scientific acceptance as a primary toxin involved in the initiation and propagation of AD pathology. We are currently focused on advancing a targeted immunotherapy drug candidate, sabirnetug, in our Phase 2 ALTITUDE-AD clinical trialtrial, followingand Phaseexpect 1to announce top-line results in “earlylate AD”2026. patientsALTITUDE-AD (patientsis a randomized, double-blind, placebo-controlled, three-arm clinical trial designed to evaluate the clinical efficacy, safety and tolerability of sabirnetug with up to 180 participants per arm for a total of 542 participants with mild cognitive impairment or mild dementia due to AD)AD. thatWe plan to use the Integrated Alzheimer’s Disease Rating Scale at 18 months as the primary outcome measure. The active doses for ALTITUDE-AD are 35 mg/kg and 50 mg/kg, dosed intravenously every four weeks. These dose levels and frequency were reportedselected inbased Julyon 2023.extensive pharmacokinetic and pharmacodynamic modeling of our Phase 1 INTERCEPT-AD clinical trial of sabirnetug. Sabirnetug is a recombinant humanized immunoglobulin gamma 2, or IgG2, monoclonal antibody, or mAb, that was designed to selectively target AßOs,AßOs. hasIn July 2023, we announced topline results from INTERCEPT-AD, which demonstrated functionalthat sabirnetug met the primary and protectivesecondary effectsobjectives of this clinical trial in in62 vitroparticipants assays,with and has demonstrated in vivo safety and pharmacologic activity in multiple animal species, including transgenic mouse models forearly AD.

During the year ended December 31, 2025, no shares of our common stock were issued under our at-the-market offering program, or the ATM. In January 2024, we issued 2,068,246 shares of our common stock under our at-the-market offering program, or the ATM, for net proceeds of $7.9 million, or $3.84 per share.

We have incurred net losses and negative cash flows from operations since our inception. Our net losses were $102.3$121.3 million and $52.4$102.3 million for the years ended December 31, 20242025 and 2023,2024, respectively. Approximately $93.8$104.9 million, or 92%,86%, of the net loss for the year ended December 31, 20242025 was due to research and development spending. As of December 31, 2024,2025, we had an accumulated deficit of $325.1$446.5 million. Our net lossesmillion and cash flowsand fromcash operations may fluctuate significantly from quarter-to-quarterequivalents and year-to-year,marketable depending on the timingsecurities of nonclinical$116.9 studies, clinical trials and our expenditures on other research and development activities.million. We expect our expenses and operating losses will increase substantially for the foreseeable future as we advance sabirnetug in clinical trials,development, seek to expand our product candidate portfolio through developing additional product candidates, grow our clinical, regulatory and quality capabilities, and incur additional costs associated with operating as a public company. It is likely that we will seek third-party collaborators for the future commercialization of sabirnetug or any other product candidate that is approved for marketing. Should we seek to commercialize our products at our own expense, we would incur significant additional expenses for marketing, sales, manufacturing and distribution. We will not generate revenue from product sales unless and until we successfully complete clinical development and obtain regulatory approval for our product candidates.

As a result, we will need substantial additional funding to support our continuing operations and pursue our growth strategy. Until we can generate significant revenue from product sales, if ever, we expect to finance our operations through a combination of public or private equity offerings and debt financings or other sources, such as potential collaboration agreements, strategic alliances and licensing arrangements. We may be unable to raise additional funds or enter into such other agreements or arrangements when needed on acceptable terms, or at all. In addition, global economic conditions may impact our ability to raise additional funds, and we may be impacted by disruptions to, and volatility in, the credit and financial markets in the United States and worldwide, tariff policy and geopolitical tensions between the United States and foreign countries, rising inflation and supply disruptions, the ongoing conflictconflicts between Russia and Ukraine, andthe Israelrecent military actions involving Iran, and Hamasthe Israel-Hamas war and related sanctions, and otherwise. If these conditions persist and deepen, we could experience an inability to access additional capital, or our liquidity could otherwise be impacted. If we are unable to raise capital when needed or on attractive terms, we would be forced to delay, reduce or eliminate our research and development programs and/or future commercialization efforts. Our failure to raise capital or enter into such agreements as,as and when needed,needed could have a material adverse effect on our business, results of operations and financial condition.

•consulting and professional fees related to research and development activities, including noncash stock-based compensation to non-employees;

•employee-related expenses, including salaries, benefits and noncash stock-based compensation expenses for our research and development personnel.

As we currently only have one product candidate, sabirnetug, in clinical development, we do not separately track expenses by program. Further, we have historically relied primarily on consultants for research and development activities; our internal research and development personnel costs currently represent approximately 16% of our total research and development expenses. Our research and development expenses increased substantially since initiating the clinical trial program for sabirnetug in 2021. We expect that our research and development expenses will continue to increase,increase substantially in connection with our continued clinical development activities for sabirnetug.

General and administrative expenses consist primarily of employee-related expenses, including noncash stock-based compensation costs, as well as business insurance, management and business consultants and other related costs. General and administrative expenses also include professional fees for legal, consulting, accounting, auditing, tax andtax, patent services, investor and public relations, recruiting expenses, board of directors’ expenses, information technology, franchise taxes, rent, travel expenses and subscriptions.

We expect that our general and administrative expenses will remain consistent for the foreseeable future and may increase as our organization and headcount required in the future grows to support continued research and development activities and potential commercialization of our product candidates. These increases will likely include increased costs related to the hiring of additional personnel and fees incurred for outside consultants, attorneys and accountants, among other expenses. Additionally, we expect to continue to incur significant expenses associated with being a public company, including costs of additional personnel, accounting, audit, legal, regulatory and tax-related services associated with maintaining compliance with exchange listing and Securities and Exchange Commission, or SEC, requirements, director and officer insurance costs, and investor and public relations costs.

Other income (expense) includes interest income, interest expense, change in fair value of embedded derivatives and other expense, net. Interest income consists of interest income earned, as well as amortization and accretion of premiums and discounts, related to our investments in marketable securities. Interest expense includes interest due under the Loan Agreement, as well as the amortization of the related debt discount. The change in fair value of embedded derivatives relates to the embedded derivatives that were bifurcated from the term loan, borrowed under the Loan Agreement, and accounted for as a derivative at fair value and which is remeasured at each reporting period for the term of the loan. Other expense, net generally consists of fees incurred on our investments in marketable securities.

Research and development expenses were $93.8$104.9 million and $42.3$93.8 million for the years ended December 31, 20242025 and 2023,2024, respectively. The $51.5$11.1 million increase was primarily due to $35.6a $15.9 million increase for manufacturing and materials mainly associated with our ALTITUDE-AD clinical trial. Additionally, we incurred a $2.6 million increase for personnel-related costs, including share-based compensation expense, a $1.1 million increase for other research expenses including EBD research, a $0.6 million increase for shipping, packaging and storage costs, a $0.4 million increase for other clinical trial costs and $0.3 million for other expenses such as insurance and software. These increased expenses were partially offset by a decrease of $4.7 million for license agreement expense, a $2.3 million decrease in CRO costs associated with theour ALTITUDE-AD clinical trial,trial formainly whichdue weto announcedpass thethrough dosingcosts, ofa the first patient in May 2024. Additionally, we incurred $5.3$1.6 million for higher personnel-related costs, which included a $1.7 million increase for non-cash stock-based compensation expenses, as well as increases in the following: $3.2 million for license agreement expenses, $2.9 million for manufacturing and materials, $1.4 million for storage, shipping and packaging, $1.1 million for other research projects, $0.8 million for other clinical trial expenses, $0.5 million for travel and conferences, $0.4 milliondecrease related to services provided by research and development contractors and consultants and $0.3a $1.2 million fordecrease otherin miscellaneousclinical costs.assay development work.

General and administrative expenses were $20.2$18.9 million and $18.8$20.2 million for the years ended December 31, 20242025 and 2023,2024, respectively. The $1.4$1.3 million increasedecrease was primarily due to increases of $2.3$0.6 million for personnelrecruiting costs,expense, including an increase of $1.8$0.4 million for non-cashcorporate stock-basedinsurance compensation expenses,expense and $0.3 million for recruiting expenses, partially offset by reductions of $0.5 million in corporate insurance expenses, $0.4 million for consulting expenses and $0.3 million for legal/patent expenses.costs.

Other income increaseddecreased by $2.9$9.2 million to $2.5 million for the year ended December 31, 2025 from $11.7 million for the year ended December 31, 2024 from $8.8 million for the year ended December 31, 2023.2024. The increasedecrease was primarily attributable to a $3.5$6.9 million increasedecrease in interest income on our portfolio of marketable securities due to botha higher interest rates and higherlower average investmentsinvestment balance in marketable securities during 2024,the asyear wellended asDecember a31, $3.02025. millionAdditionally, increasethere inwere increased expenses associated with the change in fair value of embedded derivatives due to the decrease in fair value of theour embedded derivatives thatrelated areto bifurcated from the term loan under theour Loan Agreement.Agreement of $2.1 million. These increasesdecreases in other income were partially offset by an increase in interest expense of $3.5$0.2 million related to our Loan Agreement funded in November 2023 and other expense, net of $0.1 million.

Liquidity andLiquidity, Capital Resources and Going Concern

Our operations have been financed primarily by net proceeds from the sale and issuance of our common stock and convertible preferred stock, net proceeds from our initial and subsequent public offering, orthe Private Placement and from sales of shares of our common stock under our ATM, borrowings under the IPO,Loan and the Offering,Agreement, the issuance of notes, grant revenue and, during our collaboration with Merck, which was in place from 2003 to 2011, certain payments received under our collaboration agreement.

On July 1, 2022, we filed a shelf registration statement on Form S-3, or the Registration Statement. Pursuant to the Registration Statement, we may offer and sell securities having an aggregate public offering price of up to $200.0 million. In connection with the filing of the 2022 Registration Statement, we also entered into a sales agreement, or the Sales Agreement, with BofA Securities, Inc.Inc., or BofA, and Stifel, Nicolaus & Company, Incorporated, or Stifel, as sales agents, pursuant to which we may issue and sell shares of our Commoncommon Stockstock for an aggregate offering price of up to $50.0 million under anthe ATM, which iswas included in the $200.0 million of securities that maywere beregistered offeredfor sale pursuant to the 2022 Registration Statement. On April 23, 2023, we entered into an amendment to the Sales Agreement, or,or as amended, the Amended Sales Agreement, to add BTIG, LLCLLC, or BTIG, as a sales agent under the Amended Sales Agreement. BTIG, BofA and Stifel are collectively referred to as the Sales Agents. Pursuant to the Amended Sales Agreement, we will pay the salesSales agentsAgents a commission rate of up to 3.0% of the gross proceeds from the sale of any shares of our Commoncommon Stock.stock made under the ATM. We are not obligated to make any sales of shares of our Commoncommon Stockstock under the ATM. In January 2024, we issued 2,068,246 shares of Common Stock under the ATM for net proceeds of $7.9 million, or $3.84 per share.

We enter into contracts in the normal course of business with CROs and CMOs for clinical trials, nonclinical research studies and testing, manufacturing and other services and products for operating purposes. These contracts do not contain any minimum purchase commitments and are generally cancellable by us after giving a certain amount of notice. Payments due upon cancellation consist only of payments for services provided and expenses incurred up to the date of cancellation.

Net cash provided by investing activities increased by $219.7$85.9 million to $133.9 million for the year ended December 31, 2025 from $48.0 million for the year ended December 31, 2024 from cash used in investing activities of $171.7 million for the year ended December 31, 2023,2024, and was primarily due to an increase in maturities of marketable securities of $139.8 million and a decrease in purchases of marketable securities of $79.9$132.7 million.million, partially offset by a decrease in cash provided by maturities of marketable securities of $46.7 million and an increase of $0.1 million for purchases of property and equipment.

Net cash provided by financing activities during the year ended December 31, 2025 decreased by $144.9$7.0 million tofrom cash provided by financing activities of $6.9 million for the year ended December 31, 20242024. fromCash $151.8provided millionby forfinancing activities during the year ended December 31, 2023. The decrease2024 was primarily due to anet reductionproceeds inof cash$7.9 providedmillion from the issuance of common stock ofunder $114.0our million,ATM, aspartially welloffset as a decrease in proceeds from the term loan of $30.0 million, as well as cash used ofby $0.7 million for thepayment financingunder a finance lease agreement for certain computer equipment for our Phase 2 ALTITUDE-AD clinical trial and $0.2 million offor otherpayments related to deferred offering costs.

Based on our current operating plan, we believe thatthere is substantial doubt about our existing cash and cash equivalents and marketable securities will be sufficientability to enablecontinue usas toa fundgoing concern for at least 12 months following the date of issuance of our operatingfinancial expensesstatements andincluded capital expenditure requirements into the first half of 2027. We have basedin this estimateAnnual Report on assumptionsForm that10-K. may prove to be wrong, and weWe could exhaust our available capital resources sooner than we expect, including basedif onwe our decisiondecide to initiate other clinical trials or programs. In addition, changing circumstances may cause us to increase our spending significantly faster than we currently anticipate, and we may need to spend more money than currently expected because of circumstances beyond our control. We may need to raise additional funds sooner than anticipated if we choose to expand more rapidly than we presently anticipate.

Additional funding may not be available to us on acceptable terms or at all. Any such funding may result in dilution to stockholders, imposition of debt covenants and repayment obligations or other restrictions that may affect our business. We also could be required to seek funds through arrangements with collaborative partners or otherwise that may require us to relinquish rights to some of our technologies or product candidates or otherwise agree to terms unfavorable to us. Any funds we raise may not be sufficient to enable us to continue to implement our long-term business strategy. Further, our ability to raise additional capital may be adversely impacted by potential worsening global economic conditions and the recent disruptions to and volatility in the credit and financial markets in the United States and worldwide.worldwide, as well as tariff policy and geopolitical tensions between the United States and foreign countries. Additionally, escalation in interest rates, in conjunction with banking failures, may lead to financial institutions being more prudent with capital deployment and tightening lending. If we are unable to raise sufficient additional capital on a timely basis, we could be forced to curtail our planned operations and the pursuit of our business strategy, which would have a material adverse effect on the value of our common stock.

•Expected Volatility—DuePrior to ourJanuary limited1, operating2025, historythe andCompany a lack oflacked sufficient company-specific historical and implied volatility data,information wefor haveits basedcommon ourstock estimateand ofestimated its expected stock volatility onusing a blendedweighted volatilityaverage blend of the volatility of our stock price following our IPO and the historical volatility of a grouppublicly traded set of industrypeer peerscompanies, thatas arewell publiclyas traded.its Weown willhistorical continuevolatility. toBeginning utilizeon thisJanuary blended1, approach2025, tobased estimateon volatilitythe untilavailability aof sufficient amounthistorical trading data of historicalthe informationCompany’s regardingcommon stock, the volatilityCompany ofbegan ourusing ownits stockhistorical is available.volatility.

We calculate the fair value of embedded derivatives using the Monte Carlo option-pricing model, which requires the use of various highly subjective assumptions, including the expected term, expected volatility, risk-free interest rate and expected dividend yield. Our selection of the expected volatility, risk-free interest rate and expected dividend yield are discussed above under Stock-Based Compensation Expense.

We are also a “smaller reporting company,” meaning that the market value of our shares held by non-affiliates is less than $700 million and our annual revenue was less than $100 million during the most recently completed fiscal year. We may continue to be a smaller reporting company if either (i) the market value of our shares held by non-affiliates is less than $250 million or (ii) our annual revenue wasis less than $100 million during the most recently completed fiscal year and the market value of our shares held by non-affiliates is less than $700 million. If we are a smaller reporting company at the time we cease to be an emerging growth company, we may continue to rely on exemptions from certain disclosure requirements that are available to smaller reporting companies. Specifically, as a smaller reporting company, we may choose to present only the two most recent fiscal years of audited financial statements in our Annual Report on Form 10-K and, similar to emerging growth companies, smaller reporting companies have reduced disclosure obligations regarding executive compensation.

Our business is subject to risks and events that, if they occur, could adversely affect our financial condition and results of operations and trading price of our securities. In addition to the other information set forth in this Quarterly Report on Form 10-Q, you should carefully consider the factors described in Part I, Item 1A. “Risk Factors” of our Annual Report on Form 10-K for the year ended December 31, 2025. There have been no material changes to the risk factors as described in our Annual Report on Form 10-K for the year ended December 31, 2025.2025, except as follows:

We are a clinical-stage biopharmaceutical company developing a novel disease-modifying approach targeting what we believe to be a key underlying cause of Alzheimer’s disease, or AD. Alzheimer’s disease is a progressive neurodegenerative disease of the brain that leads to loss of memory and cognitive functions and ultimately results in death. Our scientific founders pioneered research on soluble amyloid-beta oligomers, or AßOs,AβOs, which are globular assemblies of the amyloid-beta, or Aß,Aβ, peptide that are distinct from AßAβ monomers and amyloid plaques. Based on decades of research and supporting evidence, AßOsAβOs have gained increasing scientific acceptance as a primary toxin involved in the initiation and propagation of AD pathology. We are currently focused on advancing a targeted immunotherapy drug candidate, sabirnetug, in our Phase 2 ALTITUDE-AD clinical trial. We plan to announce top-line results in late 2026. Top-line results are expected to include the difference compared to placebo after 18 months as measured by the Integrated Alzheimer’s Disease Rating Scale, or iADRS, our primary clinical efficacy endpoint, as well as key secondary endpoints, such as Clinical Dementia Rating – Sum of the Boxes, or CDR-SB, certain safety measures such as adverse event rates, including amyloid-related imaging abnormalities, or ARIA rates, and key biomarkers. ALTITUDE-AD is a randomized, double-blind, placebo-controlled, three-arm clinical trial designed to evaluate the clinical efficacy, safety and tolerability of sabirnetug with up to 180 participants per arm for a total of 542 participants with mild cognitive impairment or mild dementia due to AD. We plan to use iADRS at 18 months as the primary outcome measure. The active doses for ALTITUDE-AD are 35 mg/kg and 50 mg/kg, dosed intravenously every four weeks. These dose levels and frequency were selected based on extensive pharmacokinetic and pharmacodynamic modeling of our Phase 1 INTERCEPT-AD clinical trial of sabirnetug. Sabirnetug is a recombinant humanized immunoglobulin gamma 2, or IgG2, monoclonal antibody, or mAb, that was designed to selectively target AßOs.AβOs. In July 2023, we announced top-line results from INTERCEPT-AD, which demonstrated that sabirnetug met the primary and secondary objectives of this clinical trial in 62 participants with early AD.

In addition, we are investigating a blood-brain barrier-penetrating, AßAβ oligomer-targeted Enhanced Brain Delivery™ (EBD™) therapy for the treatment of AD. In March 2026, we announced certain preclinical data from EBD candidates, including in vitro, in vivo and non-human primate study results, supporting the advancement of the EBD program: (1) EBD candidates achieved 14-40x higher brain levels in non-human primates compared to native antibodies 24 hours after dosing; (2) hematology data in non-human primates indicated low potential for anemia, including that, at 24 hours after subcutaneous dosing, EBD candidates demonstrated no observed change in red blood cell count, hematocrit, hemoglobin or reticulocyte count; and (3) favorable stability profile and enhanced brain delivery support a path to subcutaneous administration with low-volume devices. Following this robust preclinical data from both in vitro and in vivo studies, in June 2026 we announced the nomination of two EBD development candidates, ACU301 and ACU401. Based on thisthese data,developments, an investigational new drug, or IND, application for the lead candidate is targeted for mid-2027. InThis stems from our July 2025,2025 we enteredentry into a collaboration, option and license agreement with JCR Pharmaceuticals Co. Ltd., or JCR, to develop an AßAβ oligomer-targeted EBD therapy for the treatment of AD. Under the terms of the agreement, induring additionthe toyear ended December 31, 2025, we made an upfront license payment thatto JCR and, in June 2026, we paid to JCR, if we exerciseexercised our exclusive option to develop uptwo to twoEBD development candidates, JCRwhich will be eligible forrequired an option exercise payment of $9.25 million. We currently anticipatemillion that wewas will exercise our optionpaid to license two compounds developed as part of our collaboration with JCR duringin the second quarter ofJuly 2026. JCR will also be eligible to receive future milestone payments of up to $40.0 million related to development, and up to $515.0 million related to sales, for a total of up to $555.0 million, as well as single-digit percentage royalties on sales of any products that emerge from the collaboration. The combination of sabirnetug or additional, novel, AβO-selective antibodies with JCR’s blood-brain barrier-penetrating technology, J-Brain Cargo®, strengthens Acumen’s portfolio of AβO-targeted therapies. The partnership is designed to advance potential next-generation treatment options for people living with AD, by targeting the development of products with enhanced efficacy, safety and convenience.

On March 13, 2026, we entered into a securities purchase agreement with certain institutional and accredited investors for a private placement, or the Private Placement, of 10,833,331 shares of our common stock, at an offering price of $3.30 per share. The Private Placement closed on March 16, 2026, for aggregate gross proceeds of approximately $35.7 million, before deducting offering costs of approximately $0.3 million. We intend to continue to use the net proceeds from the Private Placement to primarily support our EBD program, including ongoing preclinical development work to support the nomination of a lead clinical candidate molecule, and for working capital and other general corporate purposes.

During the threesix months ended MarchJune 31,30, 2026 and 2025, no shares of our common stock were issued under our at-the-market offering program, or the ATM. Since inception, we have issued 2,068,246 shares of our common stock under the ATM, for net proceeds of $7.9 million, or $3.84 per share.

We have incurred net losses and negative cash flows from operations since our inception. Our net losses were $20.7$53.5 million and $28.8$69.7 million for the threesix months ended MarchJune 31,30, 2026 and 2025, respectively. Approximately $16.5$44.3 million, or 79%,83%, of the net loss for the threesix months ended MarchJune 31,30, 2026 was due to research and development spending. As of MarchJune 31,30, 2026, we had an accumulated deficit of $467.2$499.9 million and cash and cash equivalents and marketable securities of $128.4$110.2 million. We expect our expenses and operating losses will increase substantially for the foreseeable future as we advance sabirnetug incontinue clinical development,development activities for sabirnetug, advance our EBD program, seek to expand our product candidate portfolio through developing additional product candidates, and incur additionalongoing costs associated with operating as a public company. It is likely that we will seek third-party collaborators for the future commercialization of sabirnetug or any other product candidate that is approved for marketing. Should we seek to commercialize our products at our own expense, we would incur significant additional expenses for marketing, sales, manufacturing and distribution. We will not generate revenue from product sales unless and until we successfully complete clinical development and obtain regulatory approval for our product candidates.

As we currently only have one product candidate, sabirnetug, in clinical development, weWe do not separately track expenses by program.program as we currently have only one clinical-stage product candidate, sabirnetug, and our pre-clinical EBD development candidates, all of which are focused on the research and development of treatments for AD. Further, we have historically relied primarily on consultants for research and development activities; our internal research and development personnel costs currently represent approximately 28%21% of our total research and development expenses. Our research and development expenses increased substantially since initiating the clinical trial program for sabirnetug in 2021. We expect that our research and development expenses will continue to increase substantially in connection with our continued clinical development activities for sabirnetug.sabirnetug and the advancement of our EBD program.

Comparison of the Three Months Ended MarchJune 31,30, 2026 and 2025

The following table summarizes our results of operations for the three months ended MarchJune 31,30, 2026 and 2025 (in thousands):

Research and development expenses were $16.5$27.8 million and $25.3$37.1 million for the three months ended MarchJune 31,30, 2026 and 2025, respectively. The $8.8$9.3 million decrease was primarily due to reductions of $6.7$15.2 million for manufacturing and materials costs and $3.4$3.3 million for CRO costs, which are both associated with our ALTITUDE-AD clinical trial. Additionally, we realized a decrease of $0.4 million for other research and development expenses. Partially offsetting thesethe decreased expenses were increases of $1.0$9.3 million for license agreement expenses related to the option exercise payment owed to JCR for our exclusive option to license and develop two EBD development candidates and $0.3 million for other clinical trial expenses and $0.3 million for personnel-related costs.expenses.

General and administrative expenses were $4.7 million and $5.1$4.6 million for the three months ended MarchJune 31,30, 2026 and 2025, respectively. The $0.4$0.1 million decreaseincrease was primarily due to reductionsincreases in legalpersonnel feescosts of $0.3 million, audit and other accounting services expenses of $0.1 million, consulting expenses of $0.1$0.2 million and insurancelegal expensesfees of $0.1 million, partially offset by an increasedecreases for personnel-relatedinsurance costsexpenses of $0.2$0.1 million and consulting expenses of $0.1 million.

Other incomeexpense was $0.4 million and $1.6$0.2 million for the three months ended MarchJune 31,30, 20262026, andas 2025,compared respectively.to other income of $0.8 million for the three months ended June 30, 2025. The $1.2$1.0 million decrease was primarily attributable to a $1.4$0.9 million decrease in interest income on our portfolio of marketable securities due primarily to a lower average investment balance during the three months ended MarchJune 31,30, 2026, with the utilization of cash from investment maturities supporting our ongoing operating cash needs. Additionally, for the three months ended June 30, 2026, there was a $0.1 million increase in interest expense. Offsetting these items was theof increased incomeexpense recognized with the change in fair value of our embedded derivativesderivative related to ourthe Loan Agreement of $0.3 million.Agreement.

During the threesix months ended MarchJune 31,30, 2026 and 2025, no shares of common stock were issued under our ATM. We have issued shares of common stock for aggregate gross proceeds of $12.2 million under the ATM since the program’s inception.

As of MarchJune 31,30, 2026, we had cash and cash equivalents and marketable securities totaling $128.4$110.2 million. Our available-for-sale marketable securities mature in less than one year. We could exhaust our available capital resources sooner than we expect, including if we decide to initiate other clinical trials or programs. We evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about our ability to continue as a going concern. Based on our current operating plan, we do not expect the current balance of our cash and cash equivalents and marketable securities will be sufficient to fund our operations for at least 12 months from the date of issuance of our unaudited condensed financial statements included in this Quarterly Report on Form 10-Q. The current balance of our cash and cash equivalents and marketable securities is expected to fund our operations into early 2027. Accordingly, management has concluded that substantial doubt exists regarding our ability to continue as a going concern.

The decrease in net cash used in operations of $10.0$23.8 million to $24.1$42.2 million for the threesix months ended MarchJune 31,30, 2026, from $34.1$66.0 million for the threesix months ended MarchJune 31,30, 2025, is primarily attributable to a decrease in net loss for the threesix months ended MarchJune 31,30, 2026 of $8.1$16.3 million, an increase in noncash adjustments of $0.3$0.4 million and working capital changes of $1.6$7.1 million. Significant noncash items consisted of a decrease in noncash income for amortization and accretion on marketable securities of $0.6$0.5 million and the change in fair value of embedded derivatives of $0.3$0.2 million. Working capital changes contributed $1.6$7.1 million to the reduction in cash used in operations, including decreasesa decrease in cash used for accounts payable and accrued clinical trial expenses of $5.6 million and $1.4$16.4 million, respectively, which werewas partially offset by an increase in cash used for accrued expenses and other liabilities of $5.1$7.5 million andmillion, a decrease in cash provided by prepaid expenses and other current assets of $0.3$1.6 million and an increase in cash used for accrued clinical trial expenses of $0.1 million.

Net cash used in investing activities increased by $42.5 million to $13.8 million for the three months ended March 31, 2026 from cash provided by investing activities ofdecreased $28.7by $55.0 million to $12.2 million for the threesix months ended MarchJune 31,30, 2026 from $67.2 million for the six months ended June 30, 2025. This increasedecrease was primarily due to a decrease in proceeds from maturities and sales of marketable securities of $36.8$52.3 million,million and an increase in purchases of marketable securities of $5.8$2.8 million, partially offset by a $0.1 million decrease in purchases of property and equipment.

Net cash provided by financing activities during the threesix months ended MarchJune 31,30, 2026 increased byto $35.8$35.5 million from net cash used in financing activities of less than $0.1 million during the threesix months ended MarchJune 31,30, 2025. Cash provided by financing activities during the threesix months ended MarchJune 31,30, 2026 was primarily due to net proceeds of $35.7$35.4 million from the issuance of common stock in connection with the Private Placement and an increase of $0.1 million from the exercise of stock options, which waswere partially offset by an increase of $0.1 million paid for employee withholding taxes resulting from the repurchase of common shares following the vesting of RSUs.

Additional funding may not be available to us on acceptable terms or at all. Any such funding may result in dilution to stockholders, imposition of debt covenants and repayment obligations or other restrictions that may affect our business. We also could be required to seek funds through arrangements with collaborative partners or otherwise that may require us to relinquish rights to some of our technologies or product candidates or otherwise agree to terms unfavorable to us. Any funds we raise may not be sufficient to enable us to continue to implement our long-term business strategy. Further, our ability to raise additional capital may be adversely impacted by global economic conditions and the recent disruptions to and volatility in the credit and financial markets in the United States and worldwide, as well as tariff policy and geopolitical tensions between the United States and foreign countries. Additionally, escalation in interest rates, in conjunction with banking failures,rates may lead to financial institutions beingto become more prudentselective with capital deployment and tighteningto lending.tighten lending practices. If we are unable to raise sufficient additional capital on a timely basis, we could be forced to curtail our planned operations and the pursuit of our business strategy, which would have a material adverse effect on the value of our common stock.