Solid Biosciences Inc.

Previous wording

Since inception, we have incurred significant net losses. Our net losses were $111.5 million and $78.8 million for the six months ended June 30, 2026 and 2025, respectively. As of June 30, 2026, we had an accumulated deficit of $1.1 billion. Prior to our acquisition of AavantiBio, Inc. in December 2022 (the “Acquisition”) we devoted substantially all of our efforts to research and development, including clinical development of SGT-001, which we are no longer developing, and preclinical development of SGT‑003, as well as to building out our management team and infrastructure. Following the Acquisition, we have devoted our efforts to the research and development of our other Candidates, including clinical development of SGT‑003, SGT‑212 and SGT-501, as well as building out our management team. We expect that it could be several years before we have a commercialized product, and we may never have a commercialized product. We expect to incur significant expenses and operating losses for the foreseeable future. We anticipate that our expenses will increase substantially if, and as, we:

Current wording

Since inception, we have incurred significant net losses. Our net losses were $165.5 million and $124.5 million for the nine months ended September 30, 2026 and 2025, respectively. As of September 30, 2026, we had an accumulated deficit of $1.1 billion. Prior to our acquisition of AavantiBio, Inc. in December 2022 (the “Acquisition”) we devoted substantially all of our efforts to research and development, including clinical development of SGT-001, which we are no longer developing, and preclinical development of SGT‑003, as well as to building out our management team and infrastructure. Following the Acquisition, we have devoted our efforts to the research and development of our other Candidates, including clinical development of SGT-003, SGT-212 and SGT-501, as well as building out our management team. We expect that it could be several years before we have a commercialized product, and we may never have a commercialized product. We expect to incur significant expenses and operating losses for the foreseeable future. We anticipate that our expenses will increase substantially if, and as, we:

Previous wording

We expect our expenses to increase in connection with our ongoing activities, particularly as we continue the research and development of, conduct clinical trials of, and seek marketing approval for our Candidates. In addition, if we obtain marketing approval for our Candidates, we expect to incur significant expenses related to product sales, marketing, manufacturing and distribution. We also expect to continue to incur additional costs associated with operating as a public company. While we believe that our cash, cash equivalents and available-for-sale securities as of June 30, 2026 will be sufficient to fund our operating expenses and capital requirements into mid-2028, we have based this estimate on assumptions that may prove to be wrong, and we could use our available capital resources sooner than we currently anticipate. In order to continue to operate our business beyond that time, we will need to raise additional funds. However, there can be no assurance that we will be able to generate funds on terms acceptable to us, on a timely basis, or at all. In addition, we anticipate that we will need additional funding to complete the development of our Candidates.

Current wording

We expect our expenses to increase in connection with our ongoing activities, particularly as we continue the research and development of, conduct clinical trials of, and seek marketing approval for our Candidates. In addition, if we obtain marketing approval for our Candidates, we expect to incur significant expenses related to product sales, marketing, manufacturing and distribution. We also expect to continue to incur additional costs associated with operating as a public company. While we believe that our cash, cash equivalents and available-for-sale securities as of September 30, 2026 will be sufficient to fund our operating expenses and capital requirements into the first half of 2028, we have based this estimate on assumptions that may prove to be wrong, and we could use our available capital resources sooner than we currently anticipate. In order to continue to operate our business beyond that time, we will need to raise additional funds. However, there can be no assurance that we will be able to generate funds on terms acceptable to us, on a timely basis, or at all. In addition, we anticipate that we will need additional funding to complete the development of our Candidates.

Previous wording

Our operations to date have been limited to organizing and staffing our company, business planning, raising capital, acquiring rights to our technology, conducting research and development activities, establishing research and development collaborations, identifying and acquiring Candidates, establishing manufacturing arrangements, undertaking preclinical studies and clinical trials, and licensing of our POLARIS-101 TM capsid. As a company, we have limited experience in clinical development. We have not yet demonstrated the ability to complete clinical trials of any Candidate, obtain marketing approvals, manufacture at commercial-scale or conduct sales and marketing activities necessary for successful commercialization. Consequently, any predictions our stockholders make about our prospects may not be as accurate as they could be if we had a longer operating history or prior experience integrating acquired businesses into our existing business.

Current wording

Our operations to date have been limited to organizing and staffing our company, business planning, raising capital, acquiring rights to our technology, conducting research and development activities, establishing research and development collaborations, identifying and acquiring Candidates, establishing manufacturing arrangements, undertaking preclinical studies and clinical trials, and licensing of our POLARIS-101 capsid. As a company, we have limited experience in clinical development. We have not yet demonstrated the ability to complete clinical trials of any Candidate, obtain marketing approvals, manufacture at commercial-scale or conduct sales and marketing activities necessary for successful commercialization. Consequently, any predictions our stockholders make about our prospects may not be as accurate as they could be if we had a longer operating history or prior experience integrating acquired businesses into our existing business.

Previous wording

In addition, our ability to conduct and complete our preclinical development testing and studies is contingent on our ability to source animals and other supplies required for the conduct of such testing and studies and the performance of animal models. If we are unable to obtain all necessary animals and other supplies required for the conduct of our preclinical testing and studies, or the animal models do not perform as expected, we may be unable to complete such preclinical development testing and studies in a timely manner or at all. For example, some of our IND-enabling toxicology and other studies require certain non-human primates ("NHPs") that may be imported from countries in which trade relation with the U.S. are or may become challenging or through vendors who may not be able to timely source certain NHPs or at all, which may impair our ability to complete preclinical development testing and studies to support IND or similar applications or delay submission of such applications. Additionally, we may fail to demonstrate adequate Candidate efficacy and/or safety as required by regulatory authorities. We may fail to access relevant, adequate, or necessary animal models, including genetic models of disease and NHPs in particular, for use in such studies as requested by regulatory authorities. We may also experience substantial delays as a result of our reliance on contract research organizations (“CROs”) to conduct all animal model experimentation necessary to assess the efficacy and safety of our Candidates. Any of these factors may result in delays to Candidate progression, inability to obtain regulatory approval, and/or substantial increases in Candidate development costs.

Current wording

In addition, our ability to conduct and complete our preclinical development testing and studies is contingent on our ability to source animals and other supplies required for the conduct of such testing and studies and the performance of animal models. If we are unable to obtain all necessary animals and other supplies required for the conduct of our preclinical testing and studies, or the animal models do not perform as expected, we may be unable to complete such preclinical development testing and studies in a timely manner or at all. For example, some of our IND-enabling toxicology and other studies require certain non-human primates ("NHPs") that may be imported from countries in which trade relations with the U.S. are or may become challenging or through vendors who may not be able to timely source certain NHPs or at all, which may impair our ability to complete preclinical development testing and studies to support IND or similar applications or delay submission of such applications. Additionally, we may fail to demonstrate adequate Candidate efficacy and/or safety as required by regulatory authorities. We may fail to access relevant, adequate, or necessary animal models, including genetic models of disease and NHPs in particular, for use in such studies as requested by regulatory authorities. We may also experience substantial delays as a result of our reliance on contract research organizations (“CROs”) to conduct all animal model experimentation necessary to assess the efficacy and safety of our Candidates. Any of these factors may result in delays to Candidate progression, inability to obtain regulatory approval, and/or substantial increases in Candidate development costs.

Previous wording

Adverse side effects may be observed following administration of any AAV gene therapy, including SGT-003 or other Candidates. Not all contemplated AAV delivery systems have been validated in human clinical trials previously, such as POLARIS-101 TM, which is a novel capsid. If a delivery system does not meet the safety criteria or cannot provide the desired efficacy results, then we may be forced to suspend or terminate our development of SGT-003 or other Candidates. If certain adverse side effects were to occur in the future and we are unable to demonstrate that they were not caused by the administration process or related procedures, the FDA, the European Commission, the EMA or other regulatory authorities could order us to cease further development of, or deny approval of, SGT-003 or other Candidates for any or all targeted indications. Even if we are able to demonstrate that any serious adverse events are not product-related, such occurrences could affect participant recruitment or the ability of enrolled participants to complete the clinical trial. Participants will also create antibodies to the AAV capsid and a second administration of gene transfer might not be safe or successful.

Current wording

Adverse side effects may be observed following administration of any AAV gene therapy, including SGT-003 or other Candidates. Not all contemplated AAV delivery systems have been validated in human clinical trials previously, such as POLARIS-101, which is a novel capsid. If a delivery system does not meet the safety criteria or cannot provide the desired efficacy results, then we may be forced to suspend or terminate our development of SGT-003 or other Candidates. If certain adverse side effects were to occur in the future and we are unable to demonstrate that they were not caused by the administration process or related procedures, the FDA, the European Commission, the EMA or other regulatory authorities could order us to cease further development of, or deny approval of, SGT-003 or other Candidates for any or all targeted indications. Even if we are able to demonstrate that any serious adverse events are not product-related, such occurrences could affect participant recruitment or the ability of enrolled participants to complete the clinical trial. Participants will also create antibodies to the AAV capsid and a second administration of gene transfer might not be safe or successful.

Previous wording

In November 2019, the FDA placed a clinical hold on our clinical trial of SGT-001 following a serious adverse event in IGNITE DMD. The third participant in the 2E14 vg/kg cohort of IGNITE DMD, dosed in late October 2019, experienced a serious adverse event deemed related to the study drug that was characterized by complement activation, thrombocytopenia, decrease in red blood cell count, acute kidney injury, and cardio-pulmonary insufficiency. In April 2021, an eighth participant was treated with SGT-001. The participant experienced a systemic inflammatory response which has since fully resolved. The event was classified as a serious adverse event and considered by the investigator to be drug related. While SGT-003 utilizes POLARIS-101 TM , a different capsid than was utilized in SGT-001, and includes other changes to the construct and manufacturing process to help avoid or mitigate any such events, we cannot guarantee that similar serious adverse events or clinical holds will not happen in ongoing and future clinical trials of SGT-003. We also cannot guarantee that similar serious adverse events or clinical holds will not happen in planned and future clinical trials of any of our other Candidates.

Current wording

In November 2019, the FDA placed a clinical hold on our clinical trial of SGT-001 following a serious adverse event in IGNITE DMD. The third participant in the 2E14 vg/kg cohort of IGNITE DMD, dosed in late October 2019, experienced a serious adverse event deemed related to the study drug that was characterized by complement activation, thrombocytopenia, decrease in red blood cell count, acute kidney injury, and cardio-pulmonary insufficiency. In April 2021, an eighth participant was treated with SGT-001. The participant experienced a systemic inflammatory response which has since fully resolved. The event was classified as a serious adverse event and considered by the investigator to be drug related. While SGT-003 utilizes POLARIS-101, a different capsid than was utilized in SGT-001, and includes other changes to the construct and manufacturing process to help avoid or mitigate any such events, we cannot guarantee that similar serious adverse events or clinical holds will not happen in ongoing and future clinical trials of SGT-003. We also cannot guarantee that similar serious adverse events or clinical holds will not happen in planned and future clinical trials of any of our other Candidates.

Previous wording

We may not be able to identify, recruit and enroll a sufficient number of participants, or those with required or desired characteristics, to complete any clinical trials in a timely manner. Participant enrollment and trial completion is affected by many factors, including:

Current wording

We may not be able to identify, recruit and enroll a sufficient number of participants, or those with required or desired characteristics, to complete any clinical trials in a timely manner. Participant enrollment and trial completion are affected by many factors, including:

Previous wording

In addition, foreign regulatory authorities may change their approval policies and new regulations may be enacted. For instance, the EU pharmaceutical legislation is currently undergoing a complete review process, in the context of the Pharmaceutical Strategy for Europe initiative, launched by the European Commission in November 2020. The European Commission’s proposal for revision of several legislative instruments related to medicinal products (including potentially reducing the duration of regulatory data protection, revising the eligibility for expedited pathways, etc.) was published on April 26, 2023, with several amendments requested in April 2024. In December 2025, the European Parliament and European Council reached a provisional political agreement on the revision of EU pharmaceutical legislation, which is expected to be adopted by late-2026. Key changes include updating regulatory data exclusivity to a new system with a regulatory data protection period of eight years and a reduced market exclusivity period of one year (which can be extended if specific conditions are fulfilled), adding launch/supply obligations, incentivizing antibiotic innovation with transferable vouchers, and streamlining approval procedures in the EU. If the legislation is finalized in line with the provisional political agreement, it will have a significant impact on the pharmaceutical industry.

Current wording

In addition, foreign regulatory authorities may change their approval policies and new regulations may be enacted. In December 2025, the European Parliament and European Council reached a provisional political agreement on the revision of EU pharmaceutical legislation. The European Council formally adopted new rules on September 28, 2026, which will be considered by the European Parliament in November 2026. The new rules are expected to be approved by the European Parliament and to enter into force by late December 2026, and to become applicable in late 2028. Key changes include updating regulatory data exclusivity to a new system with a regulatory data protection period of eight years and a reduced market exclusivity period of one year (which can be extended if specific conditions are fulfilled), adding launch/supply obligations, incentivizing antibiotic innovation with transferable vouchers, and streamlining approval procedures in the EU. If the new rules are finalized in line with the provisional political agreement, they will have a significant impact on the pharmaceutical industry.

Previous wording

In 2025, the Trump Administration imposed a series of tariffs against U.S. trading partners pursuant to the International Emergency Economic Powers Act. On February 20, 2026, the U.S. Supreme Court ruled these tariffs unlawful. The Trump Administration immediately imposed new global tariffs pursuant to Section 122 of the Trade Act of 1974, which allows for tariffs of up to 15% for a period of up to 150 days. Pursuant to the statute, these tariffs expired on July 24, 2026. However, on July 23, 2026, the Office of the U.S. Trade Representative announced final action under Section 301 of the Trade Act of 1974 imposing new tariffs on imports from 60 trading partners based on findings that those countries had failed to adopt and effectively enforce prohibitions on imports of goods produced with forced labor. The new tariffs, set at either 10% or 12.5% depending on the country’s level of commitment to forced-labor import restrictions, took effect on July 24, 2026, and replaced the tariffs that had been imposed under Section 122.

Current wording

In 2025, the Trump Administration imposed a series of tariffs against U.S. trading partners pursuant to the International Emergency Economic Powers Act. On February 20, 2026, the U.S. Supreme Court ruled these tariffs unlawful. On July 23, 2026, the Office of the U.S. Trade Representative announced final action under Section 301 of the Trade Act of 1974 imposing new tariffs on imports from 60 trading partners based on findings that those countries had failed to adopt and effectively enforce prohibitions on imports of goods produced with forced labor. The new tariffs, set at either 10% or 12.5% depending on the country’s level of commitment to forced‑labor import restrictions, took effect on July 24, 2026. The forced labor tariffs have been challenged in the U.S. Court of International Trade where the litigation is currently pending while the tariffs remain in effect. The Trump Administration also announced new investigations related to excess capacity covering 21 manufacturing and industrial sectors and targeting 16 major trading partners under Section 301 of the same act, which will likely lead to additional tariffs. The deadline for final action by the Trump Administration on those investigations is March 2027.

Previous wording

Separately, in April 2025, the Department of Commerce announced an investigation under Section 232 of the Trade Expansion Act of 1962 into imports of pharmaceuticals and pharmaceutical ingredients, including finished products, medical countermeasures, critical inputs such as active pharmaceutical ingredients, and key starting materials, and derivative products of those items. U.S. trade policy remains subject to uncertainty and, accordingly, a host of other U.S. tariff actions remain possible.

Current wording

Separately, in April 2025, the Department of Commerce initiated an investigation under Section 232 of the Trade Expansion Act of 1962 into imports of pharmaceuticals and pharmaceutical ingredients, including finished products, medical countermeasures, critical inputs such as active pharmaceutical ingredients, key starting materials, and derivative products of those items. U.S. trade policy remains subject to uncertainty and, accordingly, a host of other U.S. tariff actions remain possible.

Previous wording

Under the Orphan Drug Act, the FDA may designate a product candidate as an orphan drug if it is a drug or biologic intended to treat a rare disease or condition. A similar regulatory scheme governs approval of orphan products by the EMA in the European Union. Generally, if a product candidate with an orphan drug designation subsequently receives the first marketing approval for the indication for which it has such designation, the product is entitled to a period of marketing exclusivity, which precludes the FDA or the EMA from approving another marketing application for a similar product for the same therapeutic indication for that time period. The applicable period is seven years in the United States and ten years in the European Union. The exclusivity period in the European Union can be reduced to six years if a product no longer meets the criteria for orphan drug designation, in particular if the product is sufficiently profitable so that market exclusivity is no longer justified.

Current wording

Under the Orphan Drug Act, the FDA may designate a product candidate as an orphan drug if it is a drug or biologic intended to treat a rare disease or condition. A similar regulatory scheme governs approval of orphan products by the EMA in the European Union. Generally, if a product candidate with an Orphan Drug designation subsequently receives the first marketing approval for the indication for which it has such designation, the product is entitled to a period of marketing exclusivity, which precludes the FDA or the EMA from approving another marketing application for a similar product for the same therapeutic indication for that time period. The applicable period is seven years in the United States and ten years in the European Union. The exclusivity period in the European Union can be reduced to six years if a product no longer meets the criteria for Orphan designation, in particular if the product is sufficiently profitable so that market exclusivity is no longer justified.

Previous wording

Under the current statutory sunset provisions for the Rare Pediatric Disease Priority Review Voucher Program, after September 30, 2024, the FDA may only award a voucher for an approved rare pediatric disease product application if the sponsor has rare pediatric disease designation for the drug, and that designation was granted by September 30, 2024.

Current wording

As of February 3, 2026, the pediatric disease priority review voucher program was reauthorized in the Consolidated Appropriations Act of 2026. Moreover, Congress included a sunset provision in the statute authorizing the rare pediatric disease priority review voucher program. Under the current statutory sunset provisions, the FDA may only award a voucher for an approved rare pediatric disease product application if the sponsor has rare pediatric disease designation for the product candidate and that designation is granted by September 30, 2029. After September 30, 2029, the FDA may not award any rare pediatric disease priority review vouchers.

Previous wording

After September 30, 2026, the FDA may not award any rare pediatric disease priority review vouchers. If we do not obtain approval of a BLA by these dates, and if the Rare Pediatric Disease Priority Review Voucher Program is not further extended by congressional action, we may not receive a Priority Review Voucher.

Current wording

If we do not obtain approval of a BLA by these dates, and if the Rare Pediatric Disease Priority Review Voucher Program is not further extended by congressional action, we may not receive a Priority Review Voucher.

Previous wording

There are other approaches to treat Duchenne that are either currently marketed or in development including antisense oligonucleotides, histone deacetylase (“HDAC”) inhibitors, corticosteroids, myosin inhibitors, cell therapies and gene editing. Notably, Sarepta has received accelerated approval for three therapies including Exondys 51, Vyondys 53 and Amondys 45 targeting exons 51, 53 and 45, respectively; Nippon Shinyaku received accelerated approval for Viltepso to treat exon 53 amenable patients; Avidity Biosciences is developing Del-zota to treat exon 44; Wave Life Sciences is developing WVE-N531 to treat exon 53 amenable patients; Dyne Therapeutics is developing DYNE-251 to treat exon 51 amenable patients; BioMarin Pharmaceutical is developing BMN 351 to treat exon 51 amenable patients; and Entrada Therapeutics is developing ENTR‑601-44, ENTR-601-45, ENTR-601-50, and ENTR-601-51 for exon 44, 45, 50 and 51 amenable patients, respectively. Italfarmaco received FDA approval for its HDAC inhibitor, Givinostat, in Duchenne patients who are at least 6 years of age. Santhera Pharmaceuticals received FDA approval for its corticosteroid, Agamree, which is marketed by Catalyst Pharmaceuticals, in Duchenne patients who are at least 2 years of age. Edgewise Therapeutics is developing Sevasemten, a fast skeletal myosin inhibitor, for Duchenne and Becker muscular dystrophies. Capricor Therapeutics is developing Deramiocel, an allogeneic cardiosphere-derived cell therapy product candidate. Satellos Biosciences is developing SAT-3247, an oral small molecule product candidate. Precision BioSciences is in clinical development for gene editing product candidate, PBGENE-DMD.

Current wording

There are other approaches to treat Duchenne that are either currently marketed or in development including antisense oligonucleotides, histone deacetylase (“HDAC”) inhibitors, corticosteroids, myosin inhibitors, cell therapies and gene editing. Notably, Sarepta has received accelerated approval for three therapies including Exondys 51, Vyondys 53 and Amondys 45 targeting exons 51, 53 and 45, respectively; Nippon Shinyaku received accelerated approval for Viltepso to treat exon 53 amenable patients; Avidity Biosciences, a Novartis company, has submitted a BLA for Del-zota to treat exon 44 amenable patients; Dyne Therapeutics has submitted a BLA for z-rostudirsen to treat exon 51 amenable patients; Wave Life Sciences is developing WVE-N531 to treat exon 53 amenable patients; BioMarin Pharmaceutical is developing BMN 351 to treat exon 51 amenable patients; and Entrada Therapeutics is developing ENTR-601-44, ENTR-601-45, ENTR-601-50, and ENTR-601-51 for exon 44, 45, 50 and 51 amenable patients, respectively. Italfarmaco received FDA approval for its HDAC inhibitor, Givinostat, in Duchenne patients who are at least 6 years of age. Santhera Pharmaceuticals received FDA approval for its corticosteroid, Agamree, which is marketed by Catalyst Pharmaceuticals, in Duchenne patients who are at least 2 years of age. Servier, which acquired the rights from Edgewise Therapeutics, is developing sevasemten, a fast skeletal myosin inhibitor, for Duchenne and Becker muscular dystrophies. Capricor Therapeutics has submitted a BLA for Deramiocel, an allogeneic cardiosphere-derived cell therapy product candidate. Satellos Biosciences is developing SAT-3247, an oral small molecule product candidate. Precision BioSciences is developing its gene editing product candidate, PBGENE-DMD.

Previous wording

We are also aware of a number of companies and research institutions developing gene transfer programs in FA. For example, Lexeo Therapeutics is developing an IV gene therapy to treat the cardiac manifestations of FA. Other competitors currently developing gene therapies to treat FA are in preclinical development, including Neurocrine Biosciences in collaboration with Voyager Therapeutics and Capsida Biotherapeutics. We are also aware of other companies developing non-gene therapies for FA, such as Design Therapeutics, Larimar Therapeutics, PTC Therapeutics and Papillon Therapeutics. Biogen’s SKYCLARYS®(omaveloxolone) was approved for the treatment of FA in adults and adolescents aged 16 and older by the FDA and the European Commission in February 2023 and February 2024, respectively.

Current wording

We are also aware of a number of companies and research institutions developing gene transfer programs in FA. For example, Lexeo Therapeutics is developing an IV gene therapy to treat the cardiac manifestations of FA. Other competitors currently developing gene therapies to treat FA are in preclinical development, including Neurocrine Biosciences in collaboration with Voyager Therapeutics. We are also aware of other companies developing non-gene therapies for FA, such as Design Therapeutics, Larimar Therapeutics, PTC Therapeutics, Graviton BioScience and Papillon Therapeutics. Biogen’s SKYCLARYS®(omaveloxolone) was approved for the treatment of FA in adults and adolescents aged 16 and older by the FDA and the European Commission in February 2023 and February 2024, respectively.

Previous wording

Our spending on current and future research and development programs may not yield any commercially viable Candidates. If we do not accurately evaluate the commercial potential for a particular Candidate, we may relinquish valuable rights to that Candidate through strategic collaborations, licensing or other arrangements in cases in which it would have been more advantageous for us to retain sole development and commercialization rights to such Candidate. Alternatively, we may allocate internal resources to a Candidate in a therapeutic area in which it would have been more advantageous to enter into a partnering arrangement. If any of these events occur, we may be forced to abandon our development efforts with respect to a particular Candidate or fail to develop a potentially successful Candidate.

Current wording

Our spending on current and future research and development programs may not yield any commercially viable Candidates. If we do not accurately evaluate the commercial potential for a particular Candidate, we may relinquish valuable rights to that Candidate through strategic collaborations, licensing or other arrangements in cases in which it would have been more advantageous for us to retain sole development and commercialization rights to such Candidate. Alternatively, we may allocate internal resources to a

Previous wording

The production of SGT-003, SGT-212 and SGT-501 uses a transient transfection-based process which requires processing steps that are more complex than those required for most chemical pharmaceuticals. We also intend to use transient transfection manufacturing for our other Candidates. Moreover, unlike chemical pharmaceuticals, the physical and chemical properties of a gene therapy candidate such as ours generally cannot be fully characterized. As a result, assays of the finished product may not be sufficient to ensure that the product will perform in the intended manner. Accordingly, we have and will continue to employ multiple steps to control our manufacturing processes to assure that the process works and that SGT-003, SGT-212, SGT-501 and our other Candidates are made strictly and consistently in compliance with such processes. We must supply all necessary documentation in support of an IND, BLA or MAA on a timely basis and must adhere to the FDA’s and the European Union’s cGMP requirements before we can obtain marketing approval for SGT-003, SGT-212, SGT-501, and other Candidates. In order to obtain approval, we will need to ensure that all of our processes, methods and equipment are compliant with cGMP requirements, by performing extensive audits of contract laboratories, manufacturers and suppliers.

Current wording

The production of SGT-003, SGT-212 and SGT-501 uses a transient transfection-based process which requires processing steps that are more complex than those required for most chemical pharmaceuticals. We also intend to use transient transfection manufacturing for our other Candidates. Moreover, unlike chemical pharmaceuticals, the physical and chemical properties of a gene therapy candidate such as ours generally cannot be fully characterized. As a result, assays of the finished product may not be sufficient to ensure that the product will perform in the intended manner. Additionally, delays or unfavorable results in finished product testing, including ongoing stability testing, could affect our clinical development programs and regulatory timelines. Accordingly, we have and will continue to employ multiple steps to control our manufacturing processes to assure that the process works and that SGT-003, SGT-212, SGT-501 and our other Candidates are made strictly and consistently in compliance with such processes. We must supply all necessary documentation in support of an IND, BLA or MAA on a timely basis and must adhere to the FDA’s and the European Union’s cGMP requirements before we can obtain marketing approval for SGT-003, SGT-212, SGT-501, and other Candidates. In order to obtain approval, we will need to ensure that all of our processes, methods and equipment are compliant with cGMP requirements, by performing extensive audits of contract laboratories, manufacturers and suppliers.

Previous wording

Gene transfer remains a novel technology that faces many challenges imposed by the humoral immune response. The immunogenicity of AAV gene transfers is a very complex process that we and others continue to work understand through the extensive clinical experience that now exists over a broad spectrum of therapeutic areas and indications. Marked inflammatory toxicities have been observed, including complement activation, cytopenias, severe hepatotoxicity as well as transgene related toxicities representing part of the continuum of diverse aspects of clinical immune responses that can be observed post gene transfer.

Current wording

Gene transfer remains a novel technology that faces many challenges imposed by the humoral immune response. The immunogenicity of AAV gene transfers is a very complex process that we and others continue to work to understand through the extensive clinical experience that now exists over a broad spectrum of therapeutic areas and indications. Marked inflammatory toxicities have been observed, including complement activation, cytopenias, severe hepatotoxicity as well as transgene related toxicities representing part of the continuum of diverse aspects of clinical immune responses that can be observed post gene transfer.

Previous wording

In addition, in October 2020, the HHS and the FDA published a final rule allowing states and other entities to develop a Section 804 Importation Program to import certain prescription drugs from Canada into the United States. That regulation was challenged in a lawsuit by the Pharmaceutical Research and Manufacturers of America (“PhRMA”), but the case was dismissed by a federal district court in February 2023 after the court found that PhRMA did not have standing to sue HHS. Several states have passed laws allowing for the importation of drugs from Canada. Certain of these states have submitted Section 804 Importation Program proposals and are awaiting FDA approval. Florida now has authority to import certain products from Canada for a period of two years once certain conditions are met. Florida will first need to submit a pre-import request for each product selected for importation, which must be approved by the FDA. Florida will also need to relabel the products and perform quality testing of the products to meet FDA standards. On May 21, 2025, the FDA announced that it would offer individual states the opportunity to submit a draft proposal for pre-review and meet with the agency to obtain initial feedback from the FDA prior to formally submitting their section 804 importation program proposal. The intent of these meetings is to assist states in developing their proposals by further clarifying requirements, enhancing the quality of proposals submitted to the FDA and ultimately shortening the review timeline. Further, the HHS finalized a regulation removing safe harbor protection for price reductions from pharmaceutical manufacturers to plan sponsors under Part D, either directly or through pharmacy benefit managers, unless the price reduction is required by law.

Current wording

In addition, in October 2020, the HHS and the FDA published a final rule allowing states and other entities to develop a Section 804 Importation Program to import certain prescription drugs from Canada into the United States. That regulation was challenged in a lawsuit by the Pharmaceutical Research and Manufacturers of America (“PhRMA”), but the case was dismissed by a federal district court in February 2023 after the court found that PhRMA did not have standing to sue HHS. Several states have passed laws allowing for the importation of drugs from Canada. Certain of these states have submitted Section 804 Importation Program proposals and are awaiting FDA approval. Florida now has authority to import certain products from Canada for a period of two years once certain conditions are met. Florida will first need to submit a pre-import request for each product selected for importation, which must be approved by the FDA. Florida will also need to relabel the products and perform quality testing of the products to meet FDA standards. On May 21, 2025, the FDA announced that it would offer individual states the opportunity to submit a draft proposal for pre-review and meet with the agency to obtain initial feedback from the FDA prior to formally submitting their section 804 importation program proposal. The intent of these meetings is to assist states in developing their proposals by further clarifying requirements, enhancing the quality of proposals submitted to the FDA and ultimately shortening the review timeline. Further, the

Previous wording

Specifically, with respect to price negotiations, Congress authorized Medicare to negotiate lower prices for certain costly single‑source drug and biologic products that do not have competing generics or biosimilars and are reimbursed under Medicare Part B and Part D. CMS may negotiate prices for ten high-cost drugs paid for by Medicare Part D starting in 2026, followed by 15 Part D drugs in 2027, 15 Part B or Part D drugs in 2028, and 20 Part B or Part D drugs in 2029 and beyond. This provision applies to drug products that have been approved for at least 9 years and biologics that have been licensed for 13 years, but it does not apply to drugs and biologics that have been approved for a single rare disease or condition. With passage of the OBBBA in July 2025, Congress extended this exemption to drugs and biologics with multiple orphan drug designations. The first cycle of negotiations for the Medicare Drug Price Negotiation Program commenced in the summer of 2023. On August 15, 2024, HHS published the results of the first Medicare drug price negotiations for ten selected drugs that treat a range of conditions, including diabetes, chronic kidney disease, and rheumatoid arthritis. The prices of these ten drugs will become effective January 1, 2026. In August 2024, HHS published the results of the first Medicare drug price negotiations for ten selected drugs that treat a range of conditions and the prices will become effective January 1, 2026. In January 2025, CMS announced the next 15 drug and biologic prices that will be subject to the IRA’s price negotiation provisions. This second cycle of negotiations with participating drug companies will occur during 2025, and any negotiated prices for this second set of drugs will be effective starting January 1, 2027. CMS issued a public statement on January 2025, declaring that lowering the cost of prescription drugs is a top priority of the new administration and CMS is committed to considering opportunities to bring greater transparency in the negotiation program.

Current wording

Specifically, with respect to price negotiations, Congress authorized Medicare to negotiate lower prices for certain costly single‑source drug and biologic products that do not have competing generics or biosimilars and are reimbursed under Medicare Part B and Part D. CMS may negotiate prices for ten high-cost drugs paid for by Medicare Part D starting in 2026, followed by 15 Part D drugs in 2027, 15 Part B or Part D drugs in 2028, and 20 Part B or Part D drugs in 2029 and beyond. This provision applies to drug products that have been approved for at least 9 years and biologics that have been licensed for 13 years, but it does not apply to drugs and biologics that have been approved for a single rare disease or condition. With passage of the OBBBA in July 2025, Congress extended this exemption to drugs and biologics with multiple Orphan Drug designations. The first cycle of negotiations for the Medicare Drug Price Negotiation Program commenced in the summer of 2023. On August 15, 2024, HHS published the results of the first Medicare drug price negotiations for ten selected drugs that treat a range of conditions, including diabetes, chronic kidney disease, and rheumatoid arthritis. The prices of these ten drugs became effective January 1, 2026. In January 2025, CMS announced the next 15 drug and biologic prices that will be subject to the IRA’s price negotiation provisions. This second cycle of negotiations with participating drug companies will occur during 2025, and any negotiated prices for this second set of drugs will be effective starting January 1, 2027. CMS issued a public statement in January 2025, declaring that lowering the cost of prescription drugs is a top priority of the new administration and CMS is committed to considering opportunities to bring greater transparency in the negotiation program.

Previous wording

In June 2023, Merck filed a lawsuit against HHS and CMS asserting that, among other things, the IRA’s Drug Price Negotiation Program for Medicare constitutes an uncompensated taking in violation of the Fifth Amendment of the Constitution. Subsequently, a number of other parties, including pharmaceutical companies, also filed lawsuits in various courts with similar constitutional claims against HHS and CMS. There have been various decisions by the courts considering these cases since they were filed. The HHS has generally won the substantive disputes in these cases or succeeded in getting claims dismissed for lack of standing. Most of these cases are now on appeal. In October 2024, the U.S. Court of Appeals for the Third Circuit heard oral argument in three of these cases. In May 2025, the Third Circuit rejected a pharmaceutical company’s challenge to the Medicare price negotiation program, finding that the program did not violate the company’s due process rights under the U.S. Constitution since there is no protected property interest in selling goods to Medicare beneficiaries at a price higher than what the government is willing to pay in reimbursement. We expect that litigation involving these and other provisions of the IRA will continue with unpredictable and uncertain results. Accordingly, while it is currently unclear how the IRA will be effectuated, we cannot predict with certainty what impact any federal or state health reforms will have on us, but such changes could impose new or more stringent regulatory requirements on our activities or result in reduced reimbursement for our products, any of which could adversely affect our business, results of operations and financial condition.

Current wording

In June 2023, Merck filed a lawsuit against HHS and CMS asserting that, among other things, the IRA’s Drug Price Negotiation Program for Medicare constitutes an uncompensated taking in violation of the Fifth Amendment of the Constitution. Subsequently, a number of other parties, including pharmaceutical companies, also filed lawsuits in various courts with similar constitutional claims against HHS and CMS. There have been various decisions by the courts considering these cases since they were filed. The HHS has generally won the substantive disputes in these cases or succeeded in getting claims dismissed for lack of standing. Most of these cases are now on appeal. In October 2024, the U.S. Court of Appeals for the Third Circuit heard oral argument in three of these cases. In May 2025, the Third Circuit rejected a pharmaceutical company’s challenge to the Medicare price negotiation program, finding that the program did not violate the company’s due process rights under the U.S. Constitution since there is no protected property interest in selling goods to Medicare beneficiaries at a price higher than what the government is willing to pay in reimbursement. We expect that litigation involving these and other provisions of the IRA will continue with unpredictable and uncertain results. Accordingly, while it is currently unclear how the IRA will be effectuated, we cannot predict with certainty what impact any federal or state initiatives will have on us, but such changes could impose new or more stringent regulatory requirements on our activities, could reduce coverage of, and reimbursement for our products, place downward pressure on pricing, increase rebate, discount, or other payment obligations, limit our commercial flexibility and contracting strategies, adversely affect demand for our products and otherwise adversely affect our business, results of operations and financial condition.

Previous wording

Additionally, in October 2022, President Biden signed an executive order to implement the EU-U.S. Data Privacy Framework, which serves as a replacement to the EU-U.S. Privacy Shield. The European Commission initiated the process to adopt an adequacy decision for the EU-U.S. Data Privacy Framework in December 2022 and the European Commission adopted the adequacy decision on July 10, 2023. The adequacy decision permits U.S. companies who self-certify to the EU-U.S. Data Privacy Framework to rely on it as a valid data transfer mechanism for data transfers from the EU to the U.S. However, some privacy advocacy groups have already suggested that they will be challenging the EU-U.S. Data Privacy Framework. There is currently one pending litigation against the EU-U.S. Data Privacy Framework before the CJEU. If these challenges are successful, they may not only impact the EU-U.S. Data Privacy Framework, but also further limit the viability of the standard contractual clauses and other data transfer mechanisms. The uncertainty around this issue has the potential to impact our business internationally.

Current wording

Additionally, in October 2022, President Biden signed an executive order to implement the EU-U.S. Data Privacy Framework, which serves as a replacement to the EU-U.S. Privacy Shield. The European Commission initiated the process to adopt an adequacy decision for the EU-U.S. Data Privacy Framework in December 2022 and the European Commission adopted the adequacy decision on July 10, 2023. The adequacy decision permits U.S. companies who self-certify to the EU-U.S. Data Privacy Framework to rely on it as a valid data transfer mechanism for data transfers from the EU to the U.S. However, some privacy advocacy groups have already suggested that they will be challenging the EU-U.S. Data Privacy Framework. There is currently one pending litigation against the EU-U.S. Data Privacy Framework before the CJEU. If these challenges are successful, they may not only impact the EU-U.S. Data Privacy

Previous wording

We have registered trademarks with the USPTO for the marks “SOLID BIOSCIENCES”, and “SOLID BIOSCIENCES” logo and registered marks in foreign jurisdictions for “SOLID BIOSCIENCES”, “SOLID GT” and “SOLID BIOSCIENCES” logo. Once registered, our trademarks or trade names may be challenged, infringed, diluted, tarnished, circumvented or declared generic or determined to be infringing on other marks. We may not be able to protect our rights to these trademarks and trade names, which we need to build name recognition among potential partners or customers in our markets of interest. At times, competitors may adopt trade names or trademarks similar to ours, thereby impeding our ability to build brand identity and possibly leading to market confusion. In addition, there could be potential trade name or trademark infringement, dilution or tarnishment claims brought by owners of other registered trademarks or trademarks that incorporate variations of our registered or unregistered trademarks or trade names. Over the long term, if we are unable to establish name recognition based on our trademarks and trade names, then we may not be able to compete effectively and our business may be adversely affected. Our efforts to enforce or protect our proprietary rights related to trademarks, trade secrets, domain names, copyrights or other intellectual property may be ineffective and could result in substantial costs and diversion of resources.

Current wording

We have registered trademarks with the USPTO for the marks “SOLID BIOSCIENCES”, and “SOLID BIOSCIENCES” logo and registered marks in foreign jurisdictions for “SOLID BIOSCIENCES” and “SOLID BIOSCIENCES” logo. Once registered, our trademarks or trade names may be challenged, infringed, diluted, tarnished, circumvented or declared generic or determined to be infringing on other marks. We may not be able to protect our rights to these trademarks and trade names, which we need to build name recognition among potential partners or customers in our markets of interest. At times, competitors may adopt trade names or trademarks similar to ours, thereby impeding our ability to build brand identity and possibly leading to market confusion. In addition, there could be potential trade name or trademark infringement, dilution or tarnishment claims brought by owners of other registered trademarks or trademarks that incorporate variations of our registered or unregistered trademarks or trade names. Over the long term, if we are unable to establish name recognition based on our trademarks and trade names, then we may not be able to compete effectively and our business may be adversely affected. Our efforts to enforce or protect our proprietary rights related to trademarks, trade secrets, domain names, copyrights or other intellectual property may be ineffective and could result in substantial costs and diversion of resources.

Previous wording

The Biologics Price Competition and Innovation Act of 2009 (“BPCIA”) was enacted as part of the Health Care Reform Law to establish an abbreviated pathway for the approval of biosimilar and interchangeable biological products. The regulatory pathway establishes legal authority for the FDA to review and approve biosimilar biologics, including the possible designation of a biosimilar as “interchangeable” based on its similarity to an approved biologic. Under the BPCIA, a reference biological product is granted 12 years of regulatory exclusivity from the time of first licensure of the product, and the FDA will not accept an application for a biosimilar or interchangeable product based on the reference biological product until four years after the date of first licensure of the reference product. In addition, the licensure 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 develop and receive approval of a competing biologic, so long as its BLA does not reply on the reference product, sponsor’s data or submit the application as a biosimilar application.

Current wording

The Biologics Price Competition and Innovation Act of 2009 (“BPCIA”) was enacted as part of the Health Care Reform Law to establish an abbreviated pathway for the approval of biosimilar and interchangeable biological products. The regulatory pathway establishes legal authority for the FDA to review and approve biosimilar biologics, including the possible designation of a biosimilar as “interchangeable” based on its similarity to an approved biologic. Under the BPCIA, a reference biological product is granted 12 years of regulatory exclusivity from the time of first licensure of the product, and the FDA will not accept an application for a biosimilar or interchangeable product based on the reference biological product until four years after the date of first licensure of the reference product. In addition, the licensure 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 develop and receive approval of a competing biologic, so long as its BLA does not rely on the reference product, sponsor’s data or submit the application as a biosimilar application.

Previous wording

Because we do not anticipate paying any cash dividends on our capital stock in the foreseeable future, capital appreciation, if any, is the only sole source of gain for an investment in our common stock.

Current wording

Because we do not anticipate paying any cash dividends on our capital stock in the foreseeable future, capital appreciation, if any, is the sole source of gain for an investment in our common stock.

Previous wording

(c) None of our directors or officers adopted orterminated a Rule 10b5-1 trading arrangement or a non-Rule 10b5-1 trading arrangement (as defined in Item 408(c) of Regulation S-K) during the second quarter of 2026.

Current wording

The following table describes, for the third quarter of 2026, each trading arrangement for the sale or purchase of Company securities adopted or terminated by our directors and officers that is either (1) a contract, instruction or written plan intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) (a “Rule 10b5-1 trading arrangement”) or (2) a “non-Rule 10b5-1 trading arrangement” (as defined in Item 408(c) of Regulation S-K):