Lexeo Therapeutics, Inc.

Previous wording

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 three months ended March 31, 2026 and the fiscal year ended December 31, 2025, we incurred net losses of $20.2 million and $100.0 million, respectively, and we had an accumulated deficit of $400.3 million as of March 31, 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.

Current wording

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 six months ended June 30, 2026 and the fiscal year ended December 31, 2025, we incurred net losses of $46.1 million and $100.0 million, respectively, and we had an accumulated deficit of $426.2 million as of June 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.

Previous wording

As of March 31, 2026, we had cash, cash equivalents, and investments in U.S. Treasury securities of $227.6 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 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:

Current wording

As of June 30, 2026, we had cash, cash equivalents, and investments in U.S. Treasury securities of $234.2 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:

Previous wording

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, but we have not successfully completed any clinical trial that we have internally sponsored. 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.

Current wording

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, including the pivotal trial of LX2006 initiated in 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.

Previous wording

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 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.

Current wording

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 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.

Previous wording

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, Design Therapeutics is developing a clinical stage product candidate, DT-216P2, and that PTC Therapeutics, Inc. is evaluating next steps for vatiquinone following a Complete Response Letter on their new drug application 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.

Current wording

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, nomlabofusp, Design Therapeutics is developing a clinical stage product candidate, DT-216P2, and PTC Therapeutics, Inc. has announced plans to initiate a Phase 3 study for 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.

Previous wording

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 th…

Excerpt shortened here; the source contains the full paragraph.

Current wording

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 for…

Excerpt shortened here; the source contains the full paragraph.

Previous wording

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 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.

Current wording

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, recent government 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.

Previous wording

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.

Current wording

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. 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.

Previous wording

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 Colorado, Connecticut, Delaware, Florida, Indiana, Iowa, Kentucky, Maryland, Minnesota, Montana, Nebraska, New Hampshire, New Jersey, Oregon, Rhode Island, Tennessee, Texas, Utah 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…

Excerpt shortened here; the source contains the full paragraph.

Current wording

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, Utah, 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 …

Excerpt shortened here; the source contains the full paragraph.

Previous wording

As of March 31, 2026, we had 59 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.

Current wording

As of June 30, 2026, we had 63 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.