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

we have a limited operating history, have not completed any clinical trials,history and have no products approved for commercial sale;

changes in the FDA and other government agencies, regulatory actions and other actions under the new Trumpcurrent administration could hinder their ability to hire and retain key leadership and other personnel, or otherwise prevent new products and services from being developed or commercialized in a timely manner, which could negatively impact our business; and we aremay currentlybecome subject to a lawsuit claiming, among other things, that we misappropriated the confidential information and trade secrets of Rocket, and which seeks unspecified damages and asks the court to enjoin us from competing and working in the market for gene therapy treatments targeting cardiac diseases. In the future, we may be subject to additional claims that we and our employees, consultants or independent contractors have wrongfully used or disclosed confidential information or trade secrets of third parties.

Since our inception, we have incurred significant net losses, and we expect to continue to incur significant expenses and operating losses for the foreseeable future. For the fiscal years ended December 31, 20242025 and 2023,December 31, 2024, we incurred net losses of $98.3$100.0 million and $66.4$98.3 million, respectively, and we had an accumulated deficit of $280.2$380.1 million as of December 31, 2024.2025. We have primarily financed our operations with net proceeds from the October 2025 Financing Transactions (as defined below), May 2025 Private Placement (as defined below), the March 2024 Private Placement (as defined below), net proceeds raised in our initial public offering, or IPO,IPO and the subsequent partial exercise of the underwriters’ 30-day option to purchase additional shares of common stock, as well as net proceeds from the sale of our common stock in a private placement, or the Private Placement, sales of our convertible equity securities and the convertible SAFE Note.securities. We have no products approved for commercialization and have never generated any revenue from product sales.

add operational, financial and management information systems and personnel, including personnel to support our product development and planned future commercialization efforts; and incur additional legal, accounting and other expenses inwhile operating as a public company.

As of December 31, 2024,2025, we had cash, cash equivalents, and investments in U.S. Treasury securities of $128.5$246.6 million. We believe that our cash, cash equivalents, and investments in U.S. Treasury securities balances will be sufficient to fund our operating expenses and capital requirements into 2027.2028. This estimate is based on assumptions that may prove to be wrong, and we could use our available capital resources sooner than we expect. Changes may occur beyond our control that would cause us to consume our available capital before that time, including changes in and progress of our development activities, acquisitions of additional product candidates, and changes in regulation. Our future capital requirements will depend on many factors, including:

the achievement of milestones or occurrence of other developments that trigger payments under our collaboration agreementagreements or any additional collaboration agreements we may enter into; and the costs of operating as a public company.

timely and successful completion of preclinical studies, including toxicology studies, biodistribution studies and minimally efficacious dose studies in animals, where applicable, under the FDA's GLPs;

successful enrollment and completion of clinical trials, including under the FDA's current cGCPs;

All of our product candidates are in preclinical or early clinical development, and the risk of failure is high. The preclinical studies, clinical trials and manufacturing of our product candidates are, and the manufacturing and marketing of our products, if approved, will be, subject to extensive and rigorous review and regulation by numerous government authorities in the United States and in other countries where we may test and market our product candidates. Before obtaining regulatory approvals for the commercial sale of any of our product candidates, we must demonstrate through lengthy, complex and expensive preclinical testing and clinical trials that our product candidates are both safe and effective for use in each target disease. In particular, because our product candidates are subject to regulation as biologics, we will need to demonstrate that they are sufficiently safe and of sufficient purity and potency for use in their target diseases. Each product candidate must demonstrate an adequate risk-versus-benefit profile in its intended patient population and for its intended use.

obtain marketing approval with labeling that includes significant use or distribution restrictions or safety warnings, including boxed warnings or REMS;

All of our product candidates will require extensive clinical testing before we are prepared to submit a BLABLA, or marketing authorization application, or MAA, for regulatory approval. We cannot predict with any certainty if or when we might complete the clinical development for our product candidates and submit a BLA or MAA for regulatory approval of any of our product candidates or whether any such BLA or MAA will be approved. We may also seek feedback from the FDA, EMA or other regulatory authorities on our clinical development program, and the FDA, EMA or such regulatory authorities may not provide such feedback on a timely basis, or such feedback may not be favorable, which could further delay our development programs.

Many companies in the pharmaceutical and biotechnology industries have suffered significant setbacks in late-stage clinical trials even after achieving promising results in preclinical testing and earlier-stage clinical trials. Data obtained from preclinical and clinical activities are subject to varying interpretations, which may delay, limitlimit, or prevent regulatory approval. In addition, we may experience regulatory delays or rejections as a result of many factors, including changes in regulatory policy during the period of our product candidate development. Any such delays could negatively impact our business, financial condition, results of operations and prospects.

We have obtained from the FDA Orphan Drug designation for LX2006 for the treatment of FA cardiomyopathy and for LX2020 for the treatment of PKP2-ACM. LX2006 and LX2020 have also received Orphan Medicinal Product designation from the European Commission. We may seek orphan designation for some or all of our product candidates in orphan indications in which there is a medically plausible basis for the use of these product candidates. However, we may be unsuccessful in obtaining Orphan Drug designation and may be unable to maintain the benefits associated with such designations. Even if we obtain orphan drug exclusivity for any of our product candidates, that exclusivity may not effectively protect those product candidates from competition because different drugs can be approved for the same condition, and orphan drug exclusivity does not prevent the FDA from approving the same or a different drug in another indication. Even after an orphan drug is granted orphan exclusivity and approved, the FDA can subsequently approve a later application for the same drug for the same condition before the expiration of the seven-year exclusivity period if the FDA concludes that the later drug is clinically superior in that it is shown to be safer in a substantial portion of the target populations, more effective or makes a major contribution to patient care. On August 3, 2017, Congress passed the FDA Reauthorization Act of 2017, or FDARA. FDARA, among other things, codified the FDA’s preexisting regulatory interpretation, to require that a drug sponsor demonstrate the clinical superiority of an orphan drug that is otherwise the same as a previously approved drug for the same rare disease in order to receive orphan drug exclusivity. The statute supplants prior precedent holding that the Orphan Drug Act unambiguously requires that the FDA recognize the orphan exclusivity period regardless of a showing of clinical superiority. Moreover, in the Consolidated Appropriations Act of 2021, Congress clarified that the interpretation of orphan drug exclusivity codified in FDARA would apply in cases where the FDA issued an orphan designation before the enactment of FDARA but where product approval came after the enactment of FDARA. In addition, a designated Orphan Drug may not receive orphan drug exclusivity if it is approved for a use that is broader than the disease for which it received orphan designation. In Catalyst Pharms., Inc. v. Becerra, 14 F.4th 1299 (11th Cir. 2021), the court disagreed with the FDA’s longstanding position that orphan drug exclusivity only applies to the approved use or indication within an eligible disease. This decision created uncertaintyHowever, in the application of orphan drug exclusivity. In January 2023, the FDA published a notice in the Federal Register to clarify that while the agency complies with the court’s order in Catalyst, the FDA intends to continue to apply its longstanding interpretation of the regulations to matters outside of the scope of the Catalyst order – that is, the agency will continue tying the scope of orphan-drug exclusivity to the uses or indications for which a drug is approved, which permits other sponsors to obtain approval of a drug for new uses or indications within the same orphan designated disease or condition that have not yet been approved. InThe viewConsolidated Appropriations Act of 2026, signed into law in February 2026, codified this longstanding FDA interpretation of the Orphan Drug Act. However, the overturn of the Chevron doctrine in Loper Bright Enterprises v. Raimondo, this landmark Supreme Court decisionRaimondo may invite various stakeholders to bring lawsuits against the FDA to challenge longstanding decisions and policies, including regulatory exclusivities, which could lead to uncertainties in the industry. Further, changes in the leadership of the FDA and other federal agencies under the Trumpcurrent administration may lead to new policies and changes in the regulations and operations of the FDA, which may impact our clinical development plans. We do not know if, when, or how the FDA, Congress, or future judicial challenges may change the orphan drug regulations and policies in the future, and it is uncertain how any changes might affect our business. Depending on what changes the FDA may make to its orphan drug regulations and policies, our business could be adversely impacted. Moreover, orphan drug-exclusive marketing rights in the United States may be lost if the FDA later determines that the request for designation was materially defective or if we are unable to manufacture sufficient quantities of the product to meet the needs of patients with the rare disease or condition. Orphan Drug designation neither shortens the development time or regulatory review time of a drug nor gives the drug any advantage in the regulatory review or approval process.

We may seek Fast Track, Breakthrough Therapy or RMATRegenerative Medicine Advanced Therapy, or RMAT, designation from the FDA for some or all of our product candidates, but we may be unable to obtain such designations or to maintain the benefits associated with such designations. The FDA’s Fast Track, Breakthrough Therapy, and RMAT designation programs are intended to expedite the development of certain qualifying product candidates intended for the treatment of serious diseases and conditions. If a product candidate is intended for the treatment of a serious or life-threateninglife- threatening condition and preclinical or clinical data demonstrate the product’s potential to address an unmet medical need for this condition, the sponsor may apply for FDA Fast Track designation.

We have received Fast Track designation for LX2006 for the treatment of FA cardiomyopathy, and for LX2020 for the treatment of PKP2-ACM. We have also received Breakthrough Therapy designation for LX2006 for the treatment of FA cardiomyopathy as well as RMAT designation for LX2006 for the treatment of FA cardiomyopathy. LX2006 has also been selected by the FDA to participate in its CDRP program, which is intended to facilitate expedited CMC development of investigational therapies with expedited clinical development timeframes via an increased level of communication with the FDA on CMC development. While we may seek Fast Track, Breakthrough Therapy and/or RMAT designationdesignation, or participation in the CDRP program, for some or all of our product candidates, there is no guarantee that we will be successful in obtaining any such designation. Even if we do obtain such designation, we may not experience a faster development process, review or approval compared to conventional FDA procedures. A Fast Track, Breakthrough Therapy, or RMAT designationdesignation, or participation in the CDRP program, does not ensure that the product candidate will receive marketing approval or that approval will be granted within any particular time frame. In addition, the FDA may withdraw Fast Track, Breakthrough Therapy, or RMAT designationdesignation, or remove a product candidate from the CDRP program, if it believes that the designation is no longer supported by data from our clinical development program. Fast Track, Breakthrough Therapy and/or RMAT designationdesignation, aloneor participation in the CDRP program, alone, does not guarantee qualification for the FDA’s priority review procedures.

UnderThe Consolidated Appropriations Act of 2026 extended the current statutory sunset provisions, after September 30, 2024, the FDA may only award a priority review voucher, or PRV, for an approved rare pediatric disease productPRV applicationprogram if the sponsor has Rare Pediatric Disease designation for the drug or biologic that is the subject of such application, and that designation was granted byto September 30, 2024.2029, Afterwhich September 30, 2026,means the FDA may not award any rarePRVs pediatricunder diseasethis PRVs.program However,after itSeptember is30, possible2029, theunless authorityCongress fortakes FDAfurther action to awardextend the rare pediatric disease PRVspriority willreview be further extended by Congress.program. As such, if we do not obtain approval of a marketing application for LX2006 in patients with FA on or before September 30, 2026,2029, and if the PRV program is not extended by Congressional action, we may not receive a PRV. Congress did not reauthorize the rare pediatric disease priority review program at the end of 2024, and it is unclear whether the Congress under the Trump administration will extend the program.

Where possible, we may pursue accelerated development strategies in areas of high medical need. We may seek an accelerated approval pathway for one or more of our therapeutic product candidates from the FDA, EMA or comparable foreign regulatory authorities. Under the accelerated approval provisions in the FDCA and the FDA’s implementing regulations, the FDA may grant accelerated approval to a therapeutic candidate that is designed to treat a serious or life-threatening condition, generally provides a meaningful therapeutic benefit over available therapies, and demonstrates an effect on a surrogate endpoint that is reasonably likely to predict clinical benefit or on a clinical endpoint that can be measured earlier than irreversible morbidity or mortality, or IMM,IMM that is reasonably likely to predict an effect on IMM or other clinical benefit. The FDA considers a clinical benefit to be a positive therapeutic effect that is clinically meaningful in the context of a given disease, such as IMM. For the purposes of accelerated approval, a surrogate endpoint is a marker, such as a laboratory measurement, radiographic image, physical sign, or other measure that is thought to predict clinical benefit, but is not itself a measure of clinical benefit. An intermediate clinical endpoint is a clinical endpoint that can be measured earlier than an effect on IMM that is reasonably likely to predict an effect on IMM or other clinical benefit. The accelerated approval pathway may be used in cases in which the advantage of a new product over available therapy may not be a direct therapeutic advantage, but is a clinically important improvement from a patient and public health perspective. If granted, accelerated approval is usually contingent on the sponsor’s agreement to conduct, in a diligent manner, additional post-approval confirmatory studies to verify and describe the product’s clinical benefit. If such post-approval studies fail to confirm the product’s clinical benefit, the FDA may withdraw its approval of the product. In addition, the FDA currently requires, unless otherwise informed by the agency, pre-approval of promotional materials for products receiving accelerated approval, which could adversely impact the timing of the commercial launch of the product.

All entities involved in the preparation of therapeutics for clinical trials or commercial sale, including our existing contract manufacturers for components of our product candidates, are subject to extensive regulation. Components of a finished therapeutic product approved for commercial sale or used in late-stage clinical trials in the United States and European Union must be manufactured in accordance with cGMP. These regulations govern manufacturing processes and procedures (including recordkeeping) and the implementation and operation of quality systems to control and assure the quality of investigational products and products approved for sale. Poor control of production processes can lead to the introduction of adventitious agents or other contaminants, or to inadvertent changes in the properties or stability of our product candidates that may not be detectable in final product testing. We or our contract manufacturers must supply all necessary documentation in support of a BLA or an MAA on a timely basis. Our potential manufacturing facilities and quality systems and the facilities and quality systems of some or all of our third-party contractors must pass a pre-approval inspection for compliance with the applicable regulations as a condition of regulatory approval of our product candidates or any of our other potential products. In addition, the regulatory authorities may, at any time, audit or inspect a manufacturing facility involved with the preparation of our product candidates or our other potential products or the associated quality systems for compliance with the regulations applicable to the activities being conducted, and they could put a hold on one or more of our clinical trials if the facilities of our contract manufacturing organizations, or CMOsCMOs, do not pass such audit or inspections. If these facilities do not pass a pre-approval plant inspection, FDA approval of the products will not be granted.

We rely on third-party manufacturers to manufacture our product candidates for preclinical studies and clinical trials. The manufacturers of pharmaceutical products must comply with strictly enforced cGMP requirements, state and federal regulations, as well as foreign requirements when applicable. Any failure ofby us or our CMOs to adhere to or document compliance to such regulatory requirements could lead to a delay or interruption in the availability of our product candidate materials for clinical trials or enforcement action from the FDA, EMA or foreign regulatory authorities. If we or our manufacturers fail to comply with the requirements of the FDA, EMA or other regulatory authority, sanctions could be imposed on us, including clinical holds, 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.

As product candidates proceed through preclinical studies to late-stage clinical trials towards potential approval and commercialization, it is common that various aspects of the development program, such as manufacturing methods and formulation, are altered along the way in an effort to optimize processes and product characteristics. Such changes carry the risk that they will not achieve our intended objectives. Any such changes could cause our product candidates to perform differently and affect the results of planned clinical trials or other future clinical trials conducted with the materials manufactured using altered processes. Such changes may also require additional testing, FDA notification or FDA approval. This could delay the initiation and completion of clinical trials, require the conduct of bridging clinical trials or the repetition of one or more clinical trials, increase clinical trial costs, delay approval of our product candidates and jeopardize our ability to commence sales and generate revenue. In addition, we may be required to make significant changes to our upstream and downstream processes across our pipeline, which could delay the development of our future product candidates. Regulatory agencies, and in particular the FDA and EMA, have demonstrated increased caution in their regulation of gene therapies, including increased scrutiny related to chemistry, manufacturing and control, or CMC,CMC issues. This increased regulatory scrutiny around gene therapy CMC may result in us being required to conduct additional preclinical studies or clinical trials with respect to any of our product candidates, which may result in delays and increased costs in the development or commercialization of our product candidates and ultimately could lead to the failure to obtain approval for any gene therapy product.

We currently focus our research and product development on several indications that are larger-rare diseases. However, our projections of the number of people who have the diseases we are seeking to treat, as well as the subset of people with these diseases who have the potential to benefit from treatment with our product candidates, are estimates based on our knowledge and understanding of these diseases. These estimates may prove to be incorrect and new studies may further reduce the estimated incidence or prevalence of thisthese disease.diseases. 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 candidate 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.

The total addressable market opportunity for our product candidates will ultimately depend upon a number of factors, including the diagnosis and treatment criteria included in the final label, if approved for sale in specified indications, acceptance by the medical community, patient access and product pricing and reimbursement. Incidence and prevalence estimates are frequently based on information and assumptions that are not exact and may not be accurate, and the methodology is forward-looking and potentially speculative. The process we have used in developing an estimated incidence and prevalence range for the indications we are targeting has involved collating limited data from multiple sources. Accordingly, the incidence and prevalence estimates included in this Annual Report on Form 10-K should be viewed in that context. Further, the data and statistical information used in this Annual Report, including estimates derived from them, may differ from information and estimates made by our competitors or from current or future studies conducted by independent sources.

We are aware that our competitors are developing product candidates for the treatment of diseases that our product candidates will target. With respect to LX2006, we are aware of clinical stage gene therapy programs in development at Astellas Pharma Inc. and Solid Biosciences Inc.,Inc. and those being developed in collaborations between Voyager Therapeutics, Inc. and Neurocrine Biosciences, Inc. Additionally, we are aware that Prime Medicine, Inc. and Tune Therapeutics, Inc. have early-stage gene editing discovery efforts. Among other treatment modalities for FA, we are aware that Larimar Therapeutics, Inc. is developing a clinical stage product candidate, CTI-1601, that Design Therapeutics, Inc. is developing a product candidate, DT-216P2, and that PTC Therapeutics, Inc. hasis submittedevaluating next steps for vatiquinone following a Complete Response Letter on their new drug application for vatiquinone to the FDA. Reata Pharmaceuticals, Inc.’s omaveloxolone (Skyclarys) was approved by the FDA in 2023, and Biogen Inc. acquired Reata Pharmaceuticals, Inc. for approximately $7.3 billion in the same year and is currently commercializing Skyclarys.

With respect to LX2020, both Rocket Pharmaceuticals Inc., or Rocket, and Tenaya Therapeutics Inc. are developing an AAV-based gene therapy candidate designed to deliver a functional PKP2 gene to patients with PKP2-ACM.

The ACAPatient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act, includes a subtitle called the Biologics Price Competition and Innovation Act of 2009, or BPCIA, which created an abbreviated approval pathway for biologics that are biosimilar to or interchangeable with an FDA-licensed reference biological product. Under the BPCIA, an application for a biosimilar product may not be submitted to the FDA until four years following the date that the reference product was first licensed by the FDA. In addition, the approval of a biosimilar product may not be made effective by the FDA until 12 years from the date on which the reference product was first licensed. During this 12-year period of exclusivity, another company may still market a competing version of the reference product if the FDA approves a full BLA for the competing product containing the sponsor’s own preclinical data and data from adequate and well-controlled clinical trials to demonstrate the safety, purity and potency of its product. The law is complex and is still being interpreted and implemented by the FDA. As a result, its ultimate impact, implementation and meaning are subject to uncertainty. While it is uncertain when such processes intended to implement BPCIA may be fully adopted by the FDA, any such processes could have an adverse effect on the future commercial prospects for our biologics.

We believe our success depends on obtaining and maintaining coverage and adequate reimbursement for our product candidates, including LX2006 and LX2020, and the extent to which patients will be willing to pay out-of-pocket for such products, in the absence of reimbursement for all or part of the cost. In the United States and in other countries, patients who are provided medical treatment for their conditions generally rely on third-party payors to reimburse all or part of the costs associated with their treatment. The availability of coverage and adequacy of reimbursement for our products by third-party payors, including government health care programs (e.g., Medicare, Medicaid, TRICARE), managed care providers, private health insurers, health maintenance organizations and other organizations is essential for most patients to be able to afford medical services and pharmaceutical products such as our product candidates. Third-party payors often rely upon Medicare coverage policy and payment limitations in setting their own coverage and reimbursement policies. However, decisions regarding the extent of coverage and amount of reimbursement to be provided are made on a payor-by-payor basis. One payor’s determination to provide coverage for a drug product does not assure that other payors will also provide coverage, and adequate reimbursement. For more information, see the section titled “Business – Government Regulation – Coverage and Reimbursement.”

The principal decisions about reimbursement for new medicines are typically made by CMS, an agency within the HHS. CMS decides whether and to what extent products will be covered and reimbursed under Medicare and private payors tend to follow CMS to a substantial degree. Most significantly, in August 2022, the Inflation Reduction Act of 2022, or IRA, was signed into law. Among other things, the IRA requires manufacturers of certain drugs to engage in price negotiations with Medicare, with prices that can be negotiated subject to a cap (with resulting prices for the initial ten drugs first effective in 2026); imposes rebates under Medicare Part B and Medicare Part D to penalize price increases that outpace inflation (first due in 2023); redesigns the Medicare Part D benefit (beginning in 2024); and replaces the Part D coverage gap discount program with a new discounting program (beginning in 2025). The IRA permits the Secretary of the HHS to implement many of these provisions through guidance, as opposed to regulation, for the initial years. On August 29, 2023, HHS announced the list of the first ten drugs that will be subject to price negotiations. HHS has issued and will continue to issue and update guidance implementing the IRA, although the Medicare drug price negotiation program is currently subject to legal challenges. While the impact of the IRA on the pharmaceutical industry cannot yet be fully determined, it is likely to be significant. Only high-expenditure single-source drugs that have been approved for at least 7 years (11 years for single-source biologics) can qualify for negotiation, with the negotiated price taking effect two years after the selection year. For 2026, the first year in which negotiated prices become effective, CMS selected 10 high-cost Medicare Part D drugs in 2023, negotiations began in 2024, and the negotiated maximum fair price for each drug has been announced. CMS has selected 15 additional Medicare Part D drugs for negotiated maximum fair pricing in 2027. For 2028, up to an additional 15 drugs, which may be covered under either Medicare Part B or Part D, will be selected, and for 2029 and subsequent years, up to 20 additional Part B or Part D drugs will be selected. Further, the current administration has issued executive orders focused on decreasing prescription drug prices, including directing the Secretary of HHS to establish a mechanism through which American patients can buy drugs directly from manufacturers who sell at a most-favored-nation price and directing the U.S. Trade Representative and Secretary of Commerce to take action to ensure foreign countries are not engaged in practices that purposefully and unfairly undercut market prices and drive price hikes in the United States. Government agreements with pharmaceutical companies and other government measures that use most-favored-nation pricing targets for prescription drugs, including the use of international pricing reference to set drug prices in the United States, or that increase generic and biosimilar drug entry sooner than expected, can have a material adverse effect on our industry, ability to set adequate pricing for new drugs to recover research and development costs, ability to attract potential investors and potential buyers in the future. We cannot predict the full impact of the executive orders focused on reducing prescription drug prices or increasing domestic drug manufacturing capacity, or other measures that may be implemented by the current administration related to drug pricing, drug supply chain and manufacturing in the United States. Such cost containment policies and executive orders could substantially and negatively impact the prices we may charge for any approved products, which could harm our valuation, ability to generate revenue and achieve and sustain profitability. In addition, the One Big Beautiful Bill Act, or OBBBA, which was signed into law in July 2025, includes provisions that will impact the United States healthcare system in various ways, including by cuts to Medicaid and introducing new participant work and eligibility requirements for Medicaid coverage, which are expected to significantly change the administration and applicability of Medicaid coverage. Although the full impact of the OBBBA on the healthcare system and our business is uncertain, the resulting changes may increase the cost and complexity of completing clinical development of and launching any product candidates for which we may receive regulatory approval, which could adversely affect our business and prospects.

Our collaboration with Cornell University is critical to our business and in May 2020, we entered into two separate license agreements with Cornell University pursuant to which we obtained rights under certain patents, know-how and data to exploit products and technologies covered by such intellectual property. As part of our first license agreement, as amended, we assumed oversight for the conduct of the Phase 1/2 clinical trial of LX1001 that was initiated by Cornell University at the end of 2019. As part of our second license agreement with Cornell University, as amended, we obtained certain rights to portfolios for infantile neuronal ceroid lipofuscinosis type 2 (also called CLN2 Batten disease) and FA cardiomyopathy, as well as an assignment of Cornell University’s IND to support the development of our LX1004 program. In February 2021, we further expanded our collaboration and entered into a research collaboration agreement with Cornell University to conduct preclinical research to develop the licensed technology, which expired pursuant to its terms in February 2024. We entered into a third license agreement with Cornell UniversityUniversity, or Third Cornell License Agreement, in April 2024 pursuant to which we obtained certain rights for FA cardiomyopathy, including rights to current and future clinical data from an ongoing Cornell University investigator-initiated Phase 1A trial of a gene therapy candidate AAVrh10.hFXN, known as LX2006 at Lexeo. Pursuant to theseour license agreements,agreements with Cornell University, we are obligated to diligently proceed with the development, manufacture, and sale of licensed products. If Cornell University delays or fails to perform its obligations under the license agreementsagreements, terminates any of the license agreements in accordance with its terms, or a dispute otherwise arises between the parties concerning the terms of the agreements or our respective rights to licensed technology, our pipeline of product candidates would be significantly adversely affected and our prospects may be materially harmed.

We engage CROs to help conduct our ongoing clinical trials. We expect to continue to rely on third parties, including clinical data management organizations, medical institutions and clinical investigators, to conduct those clinical trials and any future clinical trials. Any of these third parties may terminate their engagements with us, some in the event of an uncured material breach and some 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 a CRO involves substantial cost and requires managementmanagement'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.

The patent position of biotechnology and pharmaceutical companies generally is highly uncertain, involves complex legal and factual questions and has, in recent years, been the subject of much litigation. As a result, the issuance, scope, validity, enforceability and commercial value of any patent rights are highly uncertain. Our owned and licensed pending and future patent applications may not result in issued patents which protect our technology or product candidates, effectively prevent others from commercializing competitive technologies and product candidates or otherwise provide any competitive advantage. In fact, patent applications may not issue as patents at all. Even if patent applications we license or own currently or in the future issue as patents, they may not issue in a form that will provide us with any meaningful protection, prevent competitors or other third parties from competing with us, or otherwise provide us with any competitive advantage. Any patents that we hold or in-license may be challenged, narrowed, circumvented, or invalidated by third parties. Consequently, we do not know whether any of our technologies and product candidates will be protectable or remain protected by valid and enforceable patents. In addition, our existing patents and any future patents we obtain may not be sufficiently broad to prevent others from using our technology or from developing competing technologies and products, and the coverage claimed in a patent application can be significantly reduced before the patent is issued, and its scope can be reinterpreted after issuance. Any failure to obtain, maintain or defend our patents and other intellectual property could have a material adverse effect on our business, financial conditions,condition, results of operations and prospects.

In addition to the protection provided by our patent estate, we rely on trade secret protection and confidentiality agreements to protect proprietary know-how that is not amenable to patent protection. Although we generally require all of our employees to assign their inventions to us, and all of our employees, consultants, advisors and any third parties who have access to our proprietary know-how, information, or technology to enter into confidentiality agreements, we cannot provide any assurances that all such agreements have been duly executed, or that our trade secrets and other confidential proprietary information will not be disclosed. In addition, while we have undertaken reasonable efforts to ensure such agreements are enforceable and that employees and third parties comply with their obligations thereunder, these agreements may be found insufficient by a court of law or may be breached, or we may not enter into sufficient agreements with such individuals in the first instance, in either case potentially resulting in the unauthorized use or disclosure of our trade secrets and other intellectual property, including to our competitors, which could cause us to lose any competitive advantage resulting from this intellectual property. Individuals not subject to invention assignment agreements may make adverse ownership claims to our current and future intellectual property. Moreover, our competitors may independently develop knowledge, methods and know-how equivalent to our trade secrets. Competitors could purchase our products, if approved, and replicate some or all of the competitive advantages we derive from our development efforts for technologies on which we do not have patent protection. If any of our trade secrets were to be lawfully obtained or independently developed by a competitor, we would have no right to prevent them, or those to whom they communicate it, from using that technology or information to compete with us. If any of our trade secrets were to be disclosed to or independently developed by a competitor, our competitive position would be harmed. Enforcing a claim that a third-party entity illegally obtained and is using any of our trade secrets is expensive and time-consuming, and the outcome is unpredictable, and we may not be able to obtain adequate remedies for such breaches.

We are heavily reliant upon licenses to certain patent rights and proprietary technology for the development of each of our current product candidates. In particular, we in-license key patents and patent applications from Adverum related to LX2006, we in-license patent applications and know-how from Cornell University related to our LX2006, LX1001, LX1020 and LX1021 product candidates, and we in-license patent applications and know-how from UCSD,UCSD related to our LX2020, LX2021 and LX2022 product candidates. Our license agreements impose diligence and milestone and royalty payment obligations on us, and also contain certain development requirements. If we fail to comply with our obligations, our licensors may have the right to terminate our licenses, in which event we will not be able to develop, manufacture or market any product using the intellectual property under any such terminated agreement and may face other penalties. Such an occurrence would materially adversely affect our business prospects.

Certain of our licenses may not provide us with exclusive rights to use the licensed intellectual property and technology, or may not provide us with exclusive rights to use such intellectual property and technology in all relevant fields of use and in all territories in which we may wish to develop or commercialize our technology and product candidates in the future. In addition, the intellectual property rights licensed to us by our licensors, including certain intellectual property licensed by Cornell University,University UCSD, and Adverum, at least in some respects, may be used by such licensors or licensed to third parties, and such third parties may have certain enforcement rights with respect to such intellectual property. Thus, patents licensed to us could be put at risk of being invalidated or interpreted narrowly in litigation filed by or against our licensors or another licensee or in administrative proceedings brought by or against our licensors or another licensee in response to such litigation or for other reasons. As a result, we may not be able to prevent competitors or other third parties from developing and commercializing competitive products, including in territories covered by our licenses.

We currently depend, and will continue to depend, on our license agreements, including the license agreements with Cornell University and Adverum related to LX2006, with Cornell University related to our LX1001, LX1020 and LX1021 product candidates, and with UCSD,UCSD related to LX2020, LX2021 and LX2022 product candidates. The agreements under which we currently license intellectual property or technology from third parties are complex, and certain provisions in such agreements may be susceptible to multiple interpretations. The resolution of any contract interpretation disagreement that may arise could narrow what we believe to be the scope of our rights to the relevant intellectual property or technology, or increase what we believe to be our financial or other obligations under the relevant agreement, either of which could have a material adverse effect on our business, financial condition, results of operations and prospects.

These risks apply to any agreements that we may enter into in the future for our products or for any future product candidates. If we experience any of the foregoing, it could have a material adverse effect on our business, financial condition, results orof operations and prospects.

Method-of-use patents protect the use of a product for the specified method and formulation patents cover formulations of the API. These types of patents do not prevent a competitor or other third party from developing or marketing an identical product for an indication that is outside the scope of the patented method or from developing a different formulation that is outside the scope of the patented formulation. Moreover, with respect to method-of-use patents, even if competitors or other third parties do not actively promote their product for our targeted indications or uses for which we may obtain patents, physicians may recommend that patients use these products off-label, or patients may do so themselves. Although off-label use may infringe or contribute to the infringement of method-of-use patents, the practice is common, and this type of infringement is difficult to prevent or prosecute. In addition, there are numerous publications and other prior art that may be relevant to our owned or in-licensed method-of-use patents and patent applications and may be used to challenge the validity of these owned or in-licensed patents and patent applications in litigation or other intellectual property-related proceedings. If these types of challenges are successful, our owned or in-licensed patents and patent applications may be narrowed or found to be invalid, and we may lose valuable intellectual property rights. Any of the foregoing could have a material adverse effect on our business, financial conditions,condition, prospects and results of operations.

We are currently, and may in the future be,become subject to claims that we and our employees, consultants, or independent contractors have wrongfully used or disclosed confidential information or trade secrets of third parties.

We employ individuals who were previously employed at other biotechnology or biopharmaceutical companies. Although we require, evidenced by written agreements, that all of our employees, consultants and advisors not use the proprietary information or know-how of others in their work for us, we may be subject to claims that we or our employees, consultants, or independent contractors have inadvertently or otherwise used or disclosed confidential information of our employees’ former employers or other third parties. We may also be subject to claims that former employers or other third parties have an ownership interest in our future patents. Litigation may be necessary to defend against these claims.claims, Thereand there is no guarantee of success in defending these claims, and even if we are successful, litigation can have an adverse impact on us due to defense and settlement costs, diversion of management resources, harm to our reputation and other factors. For example, on October 12, 2023, Rocket filed a lawsuit against us and two former employees claiming, among other things, misappropriation of confidential information and trade secrets. The complaint alleges the individual defendants downloaded confidential Rocket company documents and other proprietary materials prior to leaving Rocket in 2021 and that we used this information to advance our programs after they became employed by Lexeo. The complaint seeks unspecified damages and asks the court to enjoin us from competing and working in the market for gene therapy treatments targeting cardiac diseases. In August 2024, we asserted counterclaims against Rocket and Spacecraft Seven LLC, a wholly owned subsidiary of Rocket, for misappropriation of trade secrets, correction of inventorship of certain patents, breach of contract, and tortious interference with contract. The case is currently in the discovery phase. It is not possible to predict the outcome with certainty and an estimate of the possible loss cannot be made. For additional information regarding this litigation, see Item 3: Legal Proceedings.claims.

we or our licensors or our other collaboration partners might not have been the first to file patent applications covering certain of the patents or patent applications that we or they own or have obtained a license,license to, or will own or will have obtained a license;

Filing and prosecuting patent applications and defending patents covering our product candidates in all countries throughout the world would be prohibitively expensive. Competitors may use our technologies in jurisdictions where we have not obtained patent protection to develop their own products and, further, may export otherwise infringing products to territories where we have patent protection, but enforcement rights are not as strong as thatthose in the United States or Europe. These products may compete with our product candidates, and our future patents or other intellectual property rights may not be effective or sufficient to prevent them from competing.

Among some of the other changes introduced by the AIA are changes that limit where a patentee may file a patent infringement suit and providingprovide opportunities for third parties to challenge any issued patent in the USPTO. This applies to all of our U.S. patents, even those issued before March 16, 2013. Because of a lower evidentiary standard in USPTO proceedings compared to the evidentiary standard in U.S. federal courts necessary to invalidate a patent claim, a third party could potentially provide evidence in a USPTO proceeding sufficient for the USPTO to hold a claim invalid even though the same evidence would be insufficient to invalidate the claim if first presented in a district court action.

Our current and future relationships with customers, healthcare providers, including physicians, and third-partythird- party payors may be subject, directly or indirectly, to federal and state healthcare fraud and abuse laws, false claims laws, health information privacy and security laws and other healthcare laws and regulations. If we are unable to comply, or have not fully complied, with such laws, we could face substantial penalties.

We are currently or will in the future be subject to healthcare regulation and enforcement by the U.S. federal government and the states in which we will conduct our business once our product candidates are approved by the FDA and commercialized in the United States. In addition to the FDA’s restrictions on marketing of pharmaceutical products, the U.S. healthcare laws and regulations that may affect our ability to operate include: the federal fraud and abuse laws, including the federal anti-kickback and false claims laws; federal data privacy and security laws; and federal transparency laws related to payments and/or other transfers of value made to physicians and other healthcare professionals and teaching hospitals. For more information, see the section titled “Business – Government Regulation – Other Healthcare Laws and Compliance Requirements.” Many states have similar laws and regulations that may differ from each other and federal law in significant ways, thus complicating compliance efforts. For example, states have anti-kickback and false claims laws that may be broader in scope than analogous federal laws and may apply regardless of payor. In addition, state laws regarding the privacy and security of health information may differ from each other and may not be preempted by federal law. Moreover, several states have enacted legislation requiring pharmaceutical manufacturers to, among other things, establish marketing compliance programs, file periodic reports with the state, make periodic public disclosures on sales and marketing activities, report information related to drug pricing, require the registration of sales representatives, and prohibit certain other sales and marketing practices. These laws may adversely affect our sales, marketing and other activities with respect to any product candidate for which we receive approval to market in the United States by imposing administrative and compliance burdens on us. It is possible that governmental authorities will conclude that our current or future business practices may not comply with current or future statutes, regulations or case law involving applicable fraud and abuse or other healthcare laws and regulations. If our operations are found to be in violation of any of these laws or any other governmental regulations that may apply to us, we may be subject to significant penalties, including, without limitation, civil, criminal and administrative penalties, damages, fines, disgorgement, individual imprisonment, exclusion from participating in federal and state funded healthcare programs, such as Medicare and Medicaid, additional reporting requirements and oversight if we become subject to a corporate integrity agreement or similar agreement to resolve allegations of non-compliance with these laws, contractual damages, diminished profits and future earnings, reputational harm and the curtailment or restructuring of our operations, any of which could harm our business.

Approval processes vary among countries and can involve additional product testing and validation and additional administrative review periods. Seeking foreign regulatory approval could result in difficulties and increased costs for us and require additional preclinical studies or clinical trials which could be costly and time consuming. Regulatory requirements can vary widely from country to country and could delay or prevent the introduction of our products in those countries. We do not have any product candidates approved for sale in any jurisdiction, including in international markets. If we fail to comply with regulatory requirements in international markets or to obtain and maintain required approvals, or if regulatory approvals in international markets are delayed, our target market will be reduced and our ability to realize the full market potential of any product we develop will be unrealized.

Any regulatory approvals that we receive for our product candidates or any future product candidates may also be subject to a REMS, limitations on the approved indicated uses for which the product may be marketed or to the conditions of approval, or requirements that we conduct potentially costly post-marketing testing, including Phase 4 trials and surveillance to monitor the quality, safety and efficacy of the product. An unsuccessful post-marketingpost- marketing study or failure to complete such a study could result in the withdrawal of marketing approval. We will further be required to immediately report any serious and unexpected adverse events and certain quality or production problems with our products to regulatory authorities along with other periodic reports.

In the United States, the European Union and other jurisdictions, there have been, and we expect there will continue to be, a number of legislative and regulatory changes and proposed changes to the healthcare system that could affect our future results of operations. In particular, there have been and continue to be a number of initiatives at the U.S. federal and state levels that seek to reduce healthcare costs and improve the quality of healthcare. For more information, see the below section titled “Business—Government Regulation—Healthcare Reform.”

Moreover, payment methodologies may be subject to changes in healthcare legislation and regulatory initiatives. For example, CMS may develop new payment and delivery models, such as bundled payment models. In addition, recently there has been heightened governmental scrutiny over the manner in which manufacturers set prices for their marketed products, which has resulted in several U.S. presidential executive orders, Congressional inquiries and proposed and enacted federal legislation designed to, among other things, bring more transparency to drug pricing, reduce the cost of prescription drugs under Medicare, and review the relationship between pricing and manufacturer patient programs. In April 2025, the President issued an executive order and an accompanying fact sheet focused on lowering drug prices, but it is unclear what actions will be implemented by the Department of Health and Human Services, CMS, and FDA under the new leadership, and how those actions will impact our industry and our business. We expect that additional U.S. federal healthcare reform measures will be adopted in the future, any of which could limit the amounts that the U.S. federal government will pay for healthcare products and services, which could result in reduced demand for our product candidates or additional pricing pressures and could negatively affect our customers and accordingly, our financial operations.

In markets outside of the United States and the European Union, reimbursement and healthcare payment systems vary significantly by country, and many countries have instituted price ceilings on specific products and therapies. We cannot predict the likelihood, nature or extent of government regulation that may arise from future legislation or administrative action in the United States, the European Union or any other jurisdiction. If we or any third parties we may engage are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if we or such third parties are not able to maintain regulatory compliance, our product candidates may lose any regulatory approval that may have been obtained and we may not achieve or sustain profitability.

Changes in fundingfederal forfunding, layoffs, government shutdown, staff departures, lapse in government appropriations, and other policies and executive order impacting the normal operations of the FDA and other government agencies could hinder their ability to hire and retain key leadership and other personnel, or otherwise prevent new products and services from being developed or commercialized in a timely manner, any of which could negatively impact our business.

The ability of the FDA to review and approve new products can be affected by a variety of factors, including government budget and funding levels, the current government shutdown, ability to hire and retain key personnel, accept the payment of user fees, and statutory, regulatory and policy changes. Average review times at the agency have fluctuated in recent years as a result. In addition, government funding of other government agencies that fund research and development activities is subject to the political process, which is inherently fluid and unpredictable. Changes in the leadership of the FDA and other federal agencies under the Trumpcurrent administration, including return-to-office policy, hiring freeze, layoffs, and other policies implemented by the Department of Government Efficiency, may lead to changes in the operations of the FDA, which may have a material impact on the industry and our clinical development plans.

Disruptions at the FDA and other agencies may also slow the time necessary for new drugs to be reviewed and/or approved by necessary government agencies, which would adversely affect our business. Additionally, changes in the FDA leadership, regulatory actions and other actions under the new Trumpcurrent administration, may result in delays in regulatory approval. Our business depends upon the ability of the FDA to accept and review our potential regulatory filings. If a prolonged government shutdown occurs or if a significant number of federal employees are laid off or leave federal agencies, 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 ability to advance clinical development of our product candidates.candidates, delay our clinical development timelines, and increase the costs of clinical development process.

If we are unable to build our own sales force or negotiate a collaborative relationship for the commercialization of LX2006, LX2020 or LX2020,LX1001, or any of our other product candidates, if approved, we may be forced to delay the potential commercialization of LX2006, or LX2020 or any of our other product candidates or reduce the scope of our sales or marketing activities for LX2006 or LX2020 or any of our other product candidates. If we elect to increase our expenditures to fund commercialization activities internationally, we will need to obtain additional capital, which may not be available to us on acceptable terms, or at all. We could enter into arrangements with collaborative partners at an earlier stage than otherwise would be ideal and we may be required to relinquish rights to LX2006,LX2006 or LX2020 or any of our other product candidates or otherwise agree to terms unfavorable to us, any of which may have an adverse effect on our business, operating results and prospects.

We maintain and otherwise process a large quantity of sensitive information, including confidential business and personal information in connection with the conduct of our clinical trials and related to our employees and others, and we are subject to laws and regulations governing the privacy and security of such information. In the United States, numerous federal and state privacy and cybersecurity laws and regulations govern the collection, use, disclosure and protection of personal information, including federal and state health information privacy laws, federal and state security breach notification laws and federal and state consumer protection laws. The legislative and regulatory landscape for privacy, data protection and cybersecurity continues to evolve, and there has been an increasing focus on privacy, data protection and cybersecurity issues, which may affect our business and is expected to increase our compliance costs and exposure to liability. In the United States, numerous federal and state laws and regulations could apply to our operations or the operations of our partners, including state and federal data breach notification laws, federal regulations prohibiting or restricting certain transfers of sensitive personal information, and state health information privacy and cybersecurity laws and federal and state consumer protection laws and regulations that govern the collection, use, disclosure and protection of health-related and other personal information. Among these regulations are: Section 5 of the Federal Trade Commission Act, which prohibits unfair or deceptive commercial practices; new rules adopted by the SEC in July 2023, which require public companies to disclose material cybersecurity incidents they experience and to disclose on an annual basis material information regarding their cybersecurity risk management, strategy, and governance; and the HIPAA, as amended by HITECH, and the regulations promulgated thereunder. We may obtain health and other data from third parties, including research institutions from which we obtain clinical trial data, that are subject to privacy and security requirements under HIPAA, and depending on the facts and circumstances, we could be subject to significant penalties if we obtain, use or disclose individually identifiable health information in a manner that is not authorized or permitted by HIPAA.

In the European Economic Area, or the EEA, and the United Kingdom, or the UK, the collection, use, disclosure, transfer or other processing of personal data, including clinical trial data, of individuals is governed by the General Data Protection Regulation, or the European Union GDPR (with regard to the EEA), and UK GDPR (with regard to the UK), as well as applicable national data protection legislation and requirements. In this document, “GDPR” refers to both the European Union GDPR and the UK GDPR, unless specified otherwise. The GDPR is wide-rangingwide ranging in scope and imposes numerous requirements on companies that process personal data, including requirements relating to processing health and other sensitive data, obtaining consent of the individuals to whom the personal data relates, providing information to individuals regarding data processing activities, implementing safeguards to protect the security and confidentiality of personal data, providing notification of data breaches, and taking certain measures when engaging third-party processors. The GDPR imposes substantial fines for breaches and violations (up to the greater of €20 million (£17.5 million for the UK) or 4% of our consolidated annual worldwide gross revenue), and confers a private right of action on data subjects and consumer associations to lodge complaints with supervisory authorities, seek judicial remedies and obtain compensation for damages resulting from violations of the GDPR.

We are a clinical stage genetic medicine company dedicated to reshaping heart health by applying pioneering science to fundamentally change how cardiovascular diseases are treated. We are advancing a portfolio of therapeutic candidates that take aim at the underlying genetic causes of conditions, including FA cardiomyopathy, PKP2plakophilin-2, or PKP2, arrhythmogenic cardiomyopathy, or ACM, and other devastating diseases with high unmet need.

To date, we have funded our operations primarily through proceeds from the sale of shares of our convertible preferred stockstock, common stock, and pre-funded warrants and warrants to purchase our common stock, including from our October 2025 Financing Transactions, May 2025 Private Placement, March 2024 Private Placement, IPO and the subsequent partial exercise of the underwriters’ 30-day option to purchase additional shares of common stock. As of December 31, 2024,2025, we had $128.5$246.6 million of cash, cash equivalents, and investments.investments in U.S. Treasury securities. We have incurred significant operating losses since the commencement of our operations. Our ability to generate product revenue sufficient to achieve profitability will depend heavily on the successful development and eventual commercialization of one or more of our current gene therapy candidates or any future gene therapy candidates. Our net losses for the years ended December 31, 20242025 and December 31, 20232024 were $98.3$100.0 million and $66.4$98.3 million, respectively, and our accumulated deficit was $280.2$380.1 million at December 31, 2024.2025. We expect to continue to incur significant losses for the foreseeable future as we advance our current and future product candidates through preclinical and clinical development, continue to build our operations and operate as a public company.

We expenserecord research and development costs as expenses when incurred. Nonrefundable advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when the payment is made. When third-party service providers’ billing terms do not coincide with our period-end, we are required to make estimates of our obligations to those third parties incurred in a given accounting period and record accruals at the end of the period. We base these estimates on our knowledge of the research and development programs, services performed for the period, past history for related activities and the expected duration of the third-party service contract, where applicable. If timelines or contracts are modified based upon changes in the scope of work to be performed, we modify our estimates of accrued expenses accordingly on a prospective basis; therefore, actual results could differ from our estimates. Upfront payments under license agreements are expensed upon receipt of the license, and annual maintenance fees under license agreements are expensed in the period in which they are incurred. Milestone payments under license agreements are accrued, with a corresponding expense being recognized, in the period in which the milestone is determined to be probable of achievement and the related amount is reasonably estimable.

General and administrative expenses consist primarily of personnel expenses, including salaries, benefits and stock-based compensation expense,expense for personnel in executive, accounting, business development, legal, human resources and administrative functions. General and administrative expenses also include corporate facility costs not otherwise included in research and development expenses, depreciation, and other expenses, which include direct or allocated expenses for rent and maintenance of facilities and insurance, not otherwise included in research and development expenses, as well as professional fees for legal, consulting, investor and public relations, accounting and audit services.

Other income (expense), net includes net foreign exchange gains and (losses).

Interest income is primarily related to interest earned from our investmentinvestments in a U.S. government money market fundfunds and interest earned from our investments in U.S. Treasury securities, as well as interest earned on interest-bearing demand deposit cash accounts.accounts and a cash collateral account.

The net increasedecrease of $21.0$10.3 million in total research and development expenses for the year ended December 31, 20242025 compared to the year ended December 31, 20232024 was primarily due to increasesdecreases in (i) clinical trial costs of $8.7 million excluding an adjustment reducing estimated accrued clinical trial expenses by $2.2 million for our LX1001 program recorded during the year ended December 31, 2024, (ii) employee compensation and stock-based compensationmilestone expenses of $8.5$6.1 millionmillion, consisting primarily due to increased headcount and equity awards granted since December 31, 2023, (iii) chemistry, manufacturing and controls, or CMC, expenses of $3.8 million, (iv) net milestone expense of $2.6 million, including a $6.0 million development milestone for our LX2020 program that was achieved during the third quarter of 2024 and subsequently paid to the selling shareholders of SteliosStelios, during(ii) theclinical yeartrial endedcosts Decemberof 31,$3.2 2024,million whichexcluding wasan partiallyadjustment offsetthat reduced estimated accrued clinical trial expenses in 2024 by a $3.5$2.2 million development milestone for our LX2006LX1001 programprogram, that(iii) was achievedemployee and paidstock-based compensation costs of $1.3 million primarily due to Adverumdecreased during the year ended December 31, 2023,headcount, (viv) quality assurance and program and portfolio managementCMC expenses of $1.0$1.2 million, and (viv) license fees of $0.7$0.6 million primarily related to the Third Cornell License Agreement.Agreement that were incurred in 2024. These increasesdecreases were partially offset by decreasesan inadjustment (i)that non-clinical and preclinical expenses of $2.5 million primarily related to our early stage cardiovascular and CNS disease programs, and (ii)reduced estimated accrued clinical trial expenses ofin 2024 by $2.2 million resulting from an adjustment recorded during the year ended December 31, 2024 for our LX1001 program.

The net increase of $16.3$13.8 million in general and administrative expenses for the year ended December 31, 20242025 compared to the year ended December 31, 20232024 was primarily due to increases in (i) employee compensation and stock-based compensation expenses of $7.3 million primarily due to increased headcount and equity awards granted since December 31, 2023, (ii) third-party legal fees and associated costs of $6.4$11.7 million, (iii) third-party audit, tax, investor relations, public relations and other professional service provider fees, as well as insuranceemployee expenses,compensation costs of $1.2$1.9 million primarily due to ourincreased becoming a publicly traded company in November 2023, (iv) travel, software, office supplies, and dues and subscription expenses of $0.6 million, and (v) capital tax expense of $0.3 million.headcount.

We recognized interest income of $7.6$6.1 million and $2.9$7.6 million for the years ended December 31, 20242025 and December 31, 2023,2024, respectively, primarily related to interest earned on our investmentinvestments in a U.S. government money market fundfunds and our investments in U.S Treasury securitiessecurities, with anthe increased average invested balance in 2024decrease primarily due to thelower netinterest proceeds received from our IPO and the subsequent partial exercise of the underwriters' option to purchase additional shares in November 2023, as well as the net proceeds received from our Private Placement offering in March 2024.rates.

Since our inception, we have not generated any revenue from product sales and have incurred significant operating losses and negative cash flows from our operations. We expect to incur significant expenses and operating losses for the foreseeable future as we advance the clinical development of our product candidates. Since our inception through December 31, 2024,2025, we funded our operations primarily with total netthrough proceeds from salesthe sale of shares of our convertible preferred stock, common stock, and pre-funded warrants and warrants to purchase our common stock, convertibleincluding SAFEfrom Noteour October 2025 Financing Transactions, May 2025 Private Placement, March 2024 Private Placement, IPO and convertiblethe equitysubsequent securitiespartial exercise of $377.9the underwriters’ 30-day option to purchase additional shares of common stock, with estimated net proceeds since our inception totaling $594.9 million. As of December 31, 20242025 and December 31, 2023,2024, we had cash, cash equivalents, and investments in U.S. Treasury Securities of $128.5$246.6 million and $121.5$128.5 million, respectively.

We believe that our cash, cash equivalents, and investments in U.S. Treasury securities balances will be sufficient to fund our planned operating expenses and capital expenditure requirements into 2027.2028. Our total future capital requirements will depend on many factors and isare subject to the risks and uncertainties set forth in “Item 1A.1A Risk Factors.”

During the year ended December 31, 2024,2025, net cash used in operating activities consisted primarily of our net loss of $98.3$100.0 million, which wasincluded partiallyan offsetunrealized bygain (i)of $12.5$3.4 million recorded to other non-operating income upon receipt of stock-basedour compensationlong-term expense,investment (ii)in $2.7convertible preferred stock, in addition to $9.5 million of net cash providedused byin changes in operating assets and liabilities, andwhich (iii)were $1.7partially offset by $12.1 million of stock-based compensation expense and $2.1 million of depreciation expense and amortization of our right-of-use assets for our operating and finance leases.right-of-use assets.

During the year ended December 31, 2023,2024, net cash used in operating activities consisted primarily of our net loss of $66.4$98.3 million, which was partially offset by (i) $3.0$12.5 million of stock-based compensation expense, (ii) $1.6 million of amortization of our right-of-use assets for our operating and finance leases, and (iii) $1.5$2.7 million of net cash provided by changes in operating assets and liabilities.liabilities, and (iii) $2.0 million of depreciation expense and amortization of operating and finance right-of-use assets.

During the year ended December 31, 2024,2025, net cash provided by financing activities consisted primarily of the net proceeds received from the October 2025 Financing Transactions of $143.9 million, the May 2025 Private Placement offering of $88.7$73.1 million, as well as $0.5proceeds received from common stock issuances under the 2023 ESPP (as defined below) of $0.3 million ofand proceeds received from the exercise of stock options,options of $0.1 million, which were partially offset by $0.4$0.5 million of principal payments made on equipment finance leases.

During the year ended December 31, 2023,2024, net cash provided by financing activities consisted primarily of the net proceeds received from the IPOMarch 2024 Private Placement of $100.3$88.7 million, as well as net$0.5 million of proceeds received from the issuanceexercise of thestock convertible SAFE Note of $3.9 million,options, which were partially offset by $0.4 million of principal payments made on equipment finance leases.

our ability to maintain our relationships with Weill Cornell Medicine,University, Adverum, The Regents of UCSD, and any other key licensors or collaborators;

We may be unable to raise additional funds or enter into potential collaborations, strategic partnerships or marketing, distribution, licensing or other similar agreements or arrangements on favorable terms, or at all. To the extent that we raise additional capital through the sale of equity or convertible debt securities, your stockholder ownership interest will be diluted. If we fail to raise capital or enter into such agreements or arrangements as, and when, needed, we may have to significantly delay, scale back or discontinue the development or commercialization of our product candidates or grant rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves.

Since our inception, we have incurred significant net losses, and we expect to continue to incur significant expenses and operating losses for the foreseeable future. For the threesix months ended MarchJune 31,30, 2026 and the fiscal year ended December 31, 2025, we incurred net losses of $20.2$46.1 million and $100.0 million, respectively, and we had an accumulated deficit of $400.3$426.2 million as of MarchJune 31,30, 2026. To date, we have primarily financed our operations with net proceeds from the sale of shares of our convertible preferred stock, common stock, and pre-funded warrants and warrants to purchase our common stock . We have no products approved for commercialization and have never generated any revenue from product sales.

As of MarchJune 31,30, 2026, we had cash, cash equivalents, and investments in U.S. Treasury securities of $227.6$234.2 million.million, and in July 2026, we sold 3,109,103 shares of our common stock under the ATM Program for net proceeds of approximately $14.1 million after transaction costs. We believe that our cash, cash equivalents and investments in U.S. Treasury securities balances will be sufficient to fund our operating expenses and capital requirements into 2028. This estimate is based on assumptions that may prove to be wrong, and we could use our available capital resources sooner than we expect. Changes may occur beyond our control that would cause us to consume our available capital before that time, including changes in and progress of our development activities, acquisitions of additional product candidates, and changes in regulation. Our future capital requirements will depend on many factors, including:

Clinical testing is expensive, can take many years to complete and is subject to uncertainty. We cannot guarantee that any clinical trials will be initiated on schedule, conducted as planned or completed on schedule, if at all. To date, we are sponsoring clinical trials of LX2006 and LX2020, butincluding wethe have not successfully completed any clinicalpivotal trial thatof weLX2006 haveinitiated internallyin sponsored.June 2026 for potential accelerated approval. Failure can occur at any time during the clinical trial process. Even if our ongoing and future clinical trials are completed as planned, we cannot be certain that their results will support the safety and effectiveness of our product candidates for their targeted diseases or support continued clinical development of such product candidates. Our future clinical trial results may not be successful.

We have received Fast Track designation for LX2006 for the treatment of FA cardiomyopathy, and for LX2020 for the treatment of PKP2-ACM. We have also received Breakthrough Therapy designation for LX2006 for the treatment of FA cardiomyopathycardiomyopathy, as well as RMAT designation for LX2006 for the treatment of FA cardiomyopathy.cardiomyopathy and for LX2020 for the treatment of PKP2-ACM. LX2006 has also been selected by the FDA to participate in its CDRP program, which is intended to facilitate expedited CMC development of investigational therapies with expedited clinical development timeframes via an increased level of communication with the FDA on CMC development. While we may seek Fast Track, Breakthrough Therapy and/or RMAT designation, or participation in the CDRP program, for some or all of our product candidates, there is no guarantee that we will be successful in obtaining any such designation. Even if we do obtain such designation, we may not experience a faster development process, review or approval compared to conventional FDA procedures. A Fast Track, Breakthrough Therapy, or RMAT designation, or participation in the CDRP program, does not ensure that the product candidate will receive marketing approval or that approval will be granted within any particular time frame. In addition, the FDA may withdraw Fast Track, Breakthrough Therapy, or RMAT designation, or remove a product candidate from the CDRP program, if it believes that the designation is no longer supported by data from our clinical development program. Fast Track, Breakthrough Therapy and/or RMAT designation, or participation in the CDRP program, alone, does not guarantee qualification for the FDA’s priority review procedures.

We are aware that our competitors are developing product candidates for the treatment of diseases that our product candidates will target. With respect to LX2006, we are aware of clinical stage gene therapy programs in development at Solid Biosciences Inc. and those being developed in collaborations between Voyager Therapeutics, Inc. and Neurocrine Biosciences, Inc. Among other treatment modalities for FA, we are aware that Larimar Therapeutics, Inc. is developing a clinical stage product candidate, CTI-1601,nomlabofusp, Design Therapeutics is developing a clinical stage product candidate, DT-216P2, and that PTC Therapeutics, Inc. ishas evaluatingannounced nextplans stepsto initiate a Phase 3 study for vatiquinone following a Complete Response Letter on their new drug application to the FDA.vatiquinone. Reata Pharmaceuticals, Inc.’s omaveloxolone (Skyclarys) was approved by the FDA in 2023, and Biogen Inc. acquired Reata Pharmaceuticals, Inc. for approximately $7.3 billion in the same year and is currently commercializing Skyclarys.

The principal decisions about reimbursement for new medicines are typically made by CMS, an agency within the HHS. CMS decides whether and to what extent products will be covered and reimbursed under Medicare and private payors tend to follow CMS to a substantial degree. Most significantly, in August 2022, the Inflation Reduction Act of 2022, or IRA, was signed into law. Among other things, the IRA requires manufacturers of certain drugs to engage in price negotiations with Medicare, with prices that can be negotiated subject to a cap (with resulting prices for the initial ten drugs first effective in 2026); imposes rebates under Medicare Part B and Medicare Part D to penalize price increases that outpace inflation (first due in 2023); redesigns the Medicare Part D benefit (beginning in 2024); and replaces the Part D coverage gap discount program with a new discounting program (beginning in 2025). The IRA permits the Secretary of the HHS to implement many of these provisions through guidance, as opposed to regulation, for the initial years. On August 29, 2023, HHS announced the list of the first ten drugs that will be subject to price negotiations. HHS has issued and will continue to issue and update guidance implementing the IRA, although the Medicare drug price negotiation program is currently subject to legal challenges. While the impact of the IRA on the pharmaceutical industry cannot yet be fully determined, it is likely to be significant. Only high-expenditure single-source drugs that have been approved for at least 7 years (11 years for single-source biologics) can qualify for negotiation, with the negotiated price taking effect two years after the selection year. For 2026, the first year in which negotiated prices become effective, CMS selected 10 high-cost Medicare Part D drugs in 2023, negotiations began in 2024, and the negotiated maximum fair price for each drug has been announced. CMS has selected 15 additional Medicare Part D drugs for negotiated maximum fair pricing in 2027. For 2028, up to an additional 15 drugs, which may be covered under either Medicare Part B or Part D, will be selected, and for 2029 and subsequent years, up to 20 additional Part B or Part D drugs will be selected. In June 2026, CMS issued a proposed rule that would codify policies established in guidance documents for the Medicare Drug Price Negotiation Program for initial price applicability year 2029 and beyond. CMS plans to release guidance to implement policies related to the effectuation of the maximum fair pricing for the Medicare Drug Price Negotiation Program for 2028. Further, the current administration has issued executive orders focused on decreasing prescription drug prices, including directing the Secretary of HHS to establish a mechanism through which American patients can buy drugs directly from manufacturers who sell at a most-favored-nation price and directing the U.S. Trade Representative and Secretary of Commerce to take action to ensure foreign countries are not engaged in practices that purposefully and unfairly undercut market prices and drive price hikes in the United States. Government agreements with pharmaceutical companies and other government measures that use most-favored-nation pricing targets for prescription drugs, including the use of international pricing reference to set drug prices in the United States, or that increase generic and biosimilar drug entry sooner than expected, can have a material adverse effect on our industry, ability to set adequate pricing for new drugs to recover research and development costs, ability to attract potential investors and potential buyers in the future. We cannot predict the full impact of the executive orders focused on reducing prescription drug prices or increasing domestic drug manufacturing capacity, or other measures that may be implemented by the current administration related to drug pricing, drug supply chain and manufacturing in the United States. Such cost containment policies and executive orders could substantially and negatively impact the prices we may charge for any approved products, which could harm our valuation, ability to generate revenue and achieve and sustain profitability. In addition, the One Big Beautiful Bill Act, or OBBBA, which was signed into law in July 2025, includes provisions that will impact the United States healthcare system in various ways, including by cuts to Medicaid and introducing new participant work and eligibility requirements for Medicaid coverage, which are expected to significantly change the administration and applicability of Medicaid coverage. Although the full impact of the OBBBA on the healthcare system and our business is uncertain, the resulting changes may increase the cost and complexity of completing clinical development of and launching any product candidates for which we may receive regulatory approval, which could adversely affect our business and prospects.

The ability of the FDA to review and approve new products can be affected by a variety of factors, including government budget and funding levels, the currentrecent government shutdown,shutdowns, ability to hire and retain key personnel, accept the payment of user fees, and statutory, regulatory and policy changes. Average review times at the agency have fluctuated in recent years as a result. In addition, government funding of other government agencies that fund research and development activities is subject to the political process, which is inherently fluid and unpredictable. Changes in the leadership of the FDA and other federal agencies under the current administration, including return-to-office policy, hiring freeze, layoffs, and other policies implemented by the Department of Government Efficiency, may lead to changes in the operations of the FDA, which may have a material impact on the industry and our clinical development plans.

The UK government made targeted amendments to its data protection regime in the Data (Use and Access) Act 2025, which entered into force in August 2025. The European Commission renewed its adequacy determination for the UK in 2025, extending to December 2031, but the UK’s adequacy determination remains subject to modification or revocation. The UK’s proposal to modify its data protection regime may impact this adequacy determination. Any loss by the UK of its adequacy determination by the European Commission may lead to additional compliance costs and could increase our overall risk. The respective provisions and enforcement of the European Union GDPR and UK GDPR may further diverge in the future and create additional regulatory challenges and uncertainties.

Compliance with these and any other applicable privacy, data protection and cybersecurity laws and regulations is a rigorous and time-intensive process, and we may be required to put in place additional mechanisms ensuring compliance with new and evolving laws and regulations. Further, many privacy, data protection, and cybersecurity regimes are evolving and are inconsistent across jurisdictions. If we fail, or are alleged to fail, to comply with any such laws or regulations, we may face regulatory inquiries, investigations, and other proceedings, private claims and litigation, and significant fines and penalties that could adversely affect our business, financial condition and results of operations. In addition, states are constantly adopting new laws or amending existing laws, requiring attention to frequently changing regulatory requirements. For example, California enacted the California Consumer Privacy Act, or CCPA, which took effect on January 1, 2020, became enforceable on July 1, 2020 and has been dubbed the first “GDPR-like” law in the United States. The CCPA gives California residents expanded rights to access and delete their personal information, opt out of certain personal information sharing and receive detailed information about how their personal information is used by requiring covered companies to provide new disclosures to California consumers (as that term is broadly defined) and provide such consumers new ways to opt out of certain sales of personal information. The CCPA provides for civil penalties for violations, as well as a private right of action for data breaches that is expected to increase data breach litigation. Further, the California Privacy Rights Act, or CPRA, which became effective as of January 1, 2023, amended the CCPA and imposes additional privacy obligations on companies doing business in California, including additional consumer rights processes, limitations on data uses, new audit requirements for higher risk data and opt outs for certain uses of sensitive data. The amendments introduced by the CPRA also created a new California Privacy Protection Agency to implement and enforce this legislation, and it is anticipated that this development could result in increased privacy and information security enforcement. Although the CCPA, as amended by the CPRA, currently exempts certain health-related information, including clinical trial data, the CCPA may increase our compliance costs and potential liability if we expand our operations into California. Similar broad consumer privacy laws have been enacted in Alabama, Colorado, Connecticut, Delaware, Florida, Indiana, Iowa, Kentucky, Maryland, Minnesota, Montana, Nebraska, New Hampshire, New Jersey, Oklahoma, Oregon, Rhode Island, Tennessee, Texas, UtahUtah, Vermont and Virginia and have been proposed in numerous other states and at the federal level. If passed, these bills may provide for various requirements that would make compliance challenging, particularly in light of certain conflicting and otherwise various requirements in the state privacy laws that have been enacted.

As of MarchJune 31,30, 2026, we had 5963 full-time employees. As our development progresses, we expect to experience significant growth in the number of our employees and the scope of our operations, particularly in the areas of clinical product development, regulatory affairs and, if any of our product candidates receives marketing approval, sales, marketing and distribution. To manage our anticipated future growth, we must continue to implement and improve our managerial, operational and financial systems, expand our facilities and continue to recruit and train additional qualified personnel. Due to our limited financial resources and the limited experience of our management team in managing a company with such anticipated growth, we may not be able to effectively manage the expansion of our operations or recruit and train additional qualified personnel. Our choice to focus on multiple therapeutic areas may negatively affect our ability to develop adequately the specialized capability and expertise necessary for operations. The expansion of our operations may lead to significant costs and may divert our management and business development resources. Any inability to manage growth could delay the execution of our business plans or disrupt our operations.

Our most advanced cardiovascular product candidate,candidate is LX2006 for the treatment of FA cardiomyopathy, is currently being evaluated in SUNRISE-FA, our ongoing Phase 1/2 clinical trial and in a Cornell investigator-initiated trial.cardiomyopathy.

In February 2026, we submitted the final registrational trial design and statistical analysis plan, or SAP, for the SUNRISE‑FA 2 pivotal study to the FDA following a Type B meeting. In June 2026, we announced that we have finalized the SUNRISE-FA 2 pivotal study protocol and SAP for LX2006, each incorporating the FDA's feedback to date and intended to support a BLA submission to the FDA in the first half of 2028 under the accelerated approval pathway. The SUNRISE-FA 2 study was initiated in June 2026. We are incontinuing contactto engage with the FDA and are awaiting final feedback onregarding the studyconfirmatory protocol.evidence Westrategy plan to provide an update whenfor the protocolSUNRISE-FA and2 SAP are finalized.study.

Increases in PKP2 protein expression versus baseline at three months in all participants that had undergone cardiac biopsies (n=7) assessed by western blot. Dose-dependent increases observed, with mean increase of 90% (previously reported 93% due to a calibration error) in the low-dose cohort (n=2) and 162% mean increase in the high-dose cohorts (n=5).

To date, we have funded our operations primarily through proceeds from the sale of shares of our convertible preferred stock, common stock, and pre-funded warrants and warrants to purchase our common stock. As of MarchJune 31,30, 2026, we had $227.6$234.2 million of cash, cash equivalents, and investments in U.S. Treasury securities.securities, and in July 2026, we sold 3,109,103 shares of our common stock under the ATM Program for net proceeds of approximately $14.1 million after transaction costs. We have incurred significant operating losses since the commencement of our operations. Our ability to generate product revenue sufficient to achieve profitability will depend heavily on the successful development and eventual commercialization of one or more of our current gene therapy candidates or any future gene therapy candidates. Our net losses for the threesix months ended MarchJune 31,30, 2026 and the year ended December 31, 2025 were $20.2$46.1 million and $100.0 million, respectively, and our accumulated deficit was $400.3$426.2 million at MarchJune 31,30, 2026. We expect to continue to incur significant losses for the foreseeable future as we advance our current and future product candidates through preclinical and clinical development, continue to build our operations and operate as a public company.

General and administrative expenses consist primarily of personnel expenses, including salaries, benefits and stock-based compensation expense for personnel in executive, accounting, business development, legal, human resources and administrative functions. General and administrative expenses also include corporate facility costs not otherwise included in research and development expenses, depreciation, and other expenses, which include direct or allocated expenses for rent and maintenance of facilities and insurance, not otherwise included in research and development expenses, as well as professional fees for legal, consulting, investor and public relations, accountingtax and audit services.

We expect that in the near to medium term future our general and administrative expenses may increase relative to those incurred during the three and six months ended MarchJune 31,30, 2026 on a quarterly basis and on an annualized basis, due to anticipated sales and marketing costs as we approach expected commercialization of our product candidates, if approved, while supporting the continued research and development of our programs and the growth of our business.

Interest expense is primarily associated with our finance right of useright-of-use asset equipment leases.

Interest income is primarily related to interest earned from our investments in U.S Treasury securities and U.S. government money market funds and interest earned from our investments in U.S. Treasury securities,funds, as well as interest earned on interest-bearing demand deposit cash accounts and a cash collateral account.

Provision for income taxes consists of U.S. federal and state income taxes in the jurisdictions where we conduct business. Since our inception, we have not recorded any income tax benefits for the net losses we have incurred in each year or for our research and development tax credits, as we believe, based upon the weight of available evidence, that it is more likely than not that all of our net operating loss, or NOL, carryforwards and tax credits will not be realized. Accordingly, we have recorded a full valuation allowance against our net deferred tax assets at MarchJune 31,30, 2026, December 31, 2025 and MarchJune 31,30, 2025. As of MarchJune 31,30, 2026, December 31, 2025 and MarchJune 31,30, 2025, we had no unrecognized tax benefits.

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):

The following table summarizes our research and development expenses incurred for the three months ended MarchJune 31,30, 2026 and 2025 (in thousands):

The net decreaseincrease of $1.5$4.3 million in total research and development expenses for the three months ended MarchJune 31,30, 2026 compared to the three months ended MarchJune 31,30, 2025 was primarily due to decreasesa net increase in (i)clinical employeetrial andexpenses of $3.1 million, as well as an increase in stock-based compensation expensesexpense of $1.5$1.3 million primarily due to decreasedthe headcount, (ii) CMC expensesachievement of $0.8performance million, and (iii) preclinical and quality expenses of $0.4 million. These decreases were primarily offset by increases in (i) clinical trial expenses of $0.5 million, (ii) milestone expenses of $0.4 millionmetrics associated with ourPerformance LX1001Restricted program,Stock andUnits, (iii)or program and portfolio management expenses of $0.3 million.PRSUs.

The net decrease of $10.0$7.0 million in general and administrative expenses for the three months ended MarchJune 31,30, 2026 compared to the three months ended MarchJune 31,30, 2025 was primarily due to decreasesa decrease in (i) third-party legal fees and associated costs of $10.5$9.7 million,million. andThis (ii)decrease employeewas andpartially offset by an increase in stock-based compensation expensesexpense of $0.4$1.3 million primarily due to decreasedthe headcount.achievement Theseof decreasesperformance weremetrics partiallyassociated offsetwith byPRSUs, increasedas well as an increase in professional services and consultant expensescosts of $0.4$0.8 million.million primarily associated with preparatory commercial market research activities.

We recognized interest income of $2.1$2.2 million and $1.2$1.3 million for the three months ended MarchJune 31,30, 2026 and MarchJune 31,30, 2025, respectively, primarily related to interest earned on our investments in U.S Treasury securities and U.S. government money market funds, our investments in U.S Treasury securities, and our interest-bearing demand deposit cash accounts, with the increase due to higher invested balances, which was partially offset by lower interest rates.

Since our inception, we have not generated any revenue from product sales and have incurred significant operating losses and negative cash flows from our operations. We expect to incur significant expenses and operating losses for the foreseeable future as we advance the clinical development of our product candidates. Since our inception through MarchJune 31,30, 2026, we funded our operations primarily through proceeds from the sale of shares of our convertible preferred stock, common stock, and pre-funded warrants and warrants to purchase our common stock. As of MarchJune 31,30, 2026 and December 31, 2025, we had cash, cash equivalents, and investments in U.S. Treasury Securities of $227.6$234.2 million and $246.6 million, respectively.

As of March 31, 2026, we had not sold any shares of common stock pursuant toDuring the ATMthree Program.and Insix Aprilmonths ended June 30, 2026, we sold 4,424,778 shares of our common stock under the ATM Program for net proceeds of approximately $23.6 million after transaction costs, and in July 2026, we sold 3,109,103 shares of our common stock under the ATM Program for net proceeds of approximately $14.1 million after transaction costs.

We believe that our cash, cash equivalents, and investments in U.S. Treasury securities balances will be sufficient to fund our planned operating expenses and capital expenditure requirements into 2028. Our total future capital requirements will depend on many factors and are subject to the risks and uncertainties set forth in “Item 1A1A. Risk Factors.”

The following table summarizes our sources and uses of cash for the threesix months ended MarchJune 31,30, 2026 and MarchJune 31,30, 2025 (in thousands):

During the threesix months ended MarchJune 31,30, 2026, net cash used in operating activities was $38.7 million and consisted primarily of our net loss of $20.2$46.1 million and $4.2 million of net cash used in changes in operating assets and liabilities,liabilities of $2.2 million, which were partially offset by $2.8$8.4 million of stock-based compensation expense and $0.5$1.1 million of depreciation expense and amortization of operating and finance right-of-use assets.

During the threesix months ended MarchJune 31,30, 2025, net cash used in operating activities was $48.9 million and consisted primarily of our net loss of $32.7$58.8 million, which included an unrealized gain of $3.4 million recorded to other non-operating income upon receipt of our long-term investment in convertible preferred stock, and which was partially offset by $6.7$6.8 million of stock-based compensation expense, $5.4 million of net cash provided by changes in operating assets and liabilities, $3.7 million of stock-based compensation expense, and $0.5$1.0 million of depreciation and amortization of operating and finance right-of-use assets.

During the threesix months ended MarchJune 31,30, 2026 and March 31, 2025,2026, net cash provided by investing activities was $27.5$41.7 million and $15.6 million, respectively, and consisted primarily of proceeds from sales or maturities of investments.investments in U.S. Treasury securities of $53.7 million, which was partially offset by $12.0 million of purchases of investments in U.S. Treasury securities.

During the threesix months ended MarchJune 31,30, 2026, net cash provided by financing activities was $26.9 million and consisted primarily of proceeds received from the sale of shares of our common stock under the ATM Program of $24.2 million net of $0.8 million of related transaction costs paid during the period, the exercise of common warrants of $2.4 million, as well as proceeds received fromand common stock issuances under the 2023 ESPP of $0.1 million, which were partially offset by $0.1$0.3 million of principal payments made on equipment finance leases.

During the threesix months ended MarchJune 31,30, 2025, net cash provided by financing activities was $73.0 million and consisted primarily of the net proceeds received from the May 2025 Private Placement offering of $73.1 million, as well as proceeds received from the common stock issuances under the 2023 ESPP of $0.2 million, which waswere partially offset by $0.2$0.3 million of principal payments made on equipment finance leases.

Other than as disclosed in Note 2 to the unaudited condensed financial statements included in this Quarterly Report on Form 10-Q, there have been no significant changes to our critical accounting estimates from those described in our audited financial statements as of and for the year ended December 31, 2025 included in our Annual Report on Form 10-K, filed with the SEC on March 30, 2026.