SLDB US Equity☆

Item 7.Management’s Discussion and Analysis of Financial Condition and Results of Operations.

The following discussion and analysis of our financial condition and results of operations should be read in conjunction with our financial statements and related notes appearing elsewhere in this Annual Report on Form 10-K. Some of the information contained in this discussion and analysis or set forth elsewhere in this Annual Report on Form 10-K, including information with respect to our plans and strategy for our business, includes forward-looking statements that involve risks and uncertainties. As a result of many factors, including those factors set forth in the “Risk Factors” section of this Annual Report on Form 10-K, our actual results could differ materially from the results described, in or implied, by these forward-looking statements.

Overview

Our mission is to cure Duchenne muscular dystrophy, or Duchenne, a genetic muscle-wasting disease predominantly affecting boys, with symptoms that usually manifest between three and five years of age. Duchenne is a progressive, irreversible and ultimately fatal disease that affects approximately one in every 3,500 to 5,000 live male births and has an estimated prevalence of 5,000 to 15,000 cases in the United States alone. Duchenne is caused by mutations in the dystrophin gene, which result in the absence or near-absence of dystrophin protein. Dystrophin protein works to strengthen muscle fibers and protect them from daily wear and tear. Without functioning dystrophin and certain associated proteins, muscles suffer excessive damage from normal daily activities and are unable to regenerate, leading to the build-up of fibrotic, or scar, and fat tissue. There is no cure for Duchenne and, for the vast majority of patients, there are no satisfactory symptomatic or disease-modifying treatments.

Our efforts are focused on our lead product candidate, SGT-001, a gene transfer candidate under investigation for its ability to drive functional dystrophin protein expression in patients’ muscles and improve the course of the disease, as well as SGT-003, our next-generation gene therapy candidate for the treatment of Duchenne.

In addition, we are actively involved in engaging with the Duchenne patient, clinical and research communities to support advancement of therapies for patients with Duchenne. In November 2021, in collaboration with REGENXBIO, we formally launched the Pathway Development Consortium, or the PDC, a multistakeholder initiative which aims to identify, develop, expand and maintain pathways to effective therapies for patients diagnosed early in life with rare diseases, including Duchenne. The PDC seeks to achieve these goals by bringing together a broad and diverse group of stakeholders from the rare disease and AAV gene therapy communities, including patients, industry, regulators, academia and payers, among others, for meaningful scientific and policy discussions.

To date, nine patients have been dosed in IGNITE DMD with SGT-001. In 2021, we dosed three patients in February (Patient 7), April (Patient 8) and November (Patient 9) in the 2E14 vg/kg cohort with SGT-001. All three patients were dosed with our second generation manufacturing process. Patients 7 and 9 were safely dosed, with transient and manageable adverse events, none of which were serious. Patient 8 experienced a systemic inflammatory response which has since fully resolved. The event was classified as a serious adverse event, or SAE, and considered to be drug related. The type of event is described in our Investigators Brochure and is not considered unexpected. Following the dosing of Patient 8, we conducted an extensive review of all clinical data from IGNITE DMD, which resulted in a strengthened risk mitigation plan that was submitted to the U.S. Food and Drug Administration, or the FDA, and implemented prior to the dosing of the Patient 9.

In 2021, we reported long-term biomarker data from biopsies of skeletal muscle from IGNITE DMD patients four through six taken 24 months, 18 months and 12 months post-dosing, respectively. In addition, we reported interim safety and efficacy data for motor function as assessed by North Star Ambulatory Assessment, or NSAA, and 6-Minute Walk Test, or 6MWT, pulmonary function as assessed by pulmonary function tests, or PFTs, including forced vital capacity, or FVC, peak expiratory flow, or PEF, forced expiratory volume in one second, or FEV1, as well as patient reported outcome measures, or PROMs, as assessed by the key functional domains of the Pediatric Outcomes Data Collection Instrument, or PODCI at the 12-month and 18-month post-dosing time points.

In March 2022, we announced two-year interim safety and efficacy data from the first three Patients (Patients 4-6) treated with SGT-001 in the 2E14 vg/kg dose cohort of IGNITE DMD. Results suggested durable benefit 24-months post-administration of SGT-001, when compared to natural history. These data were consistent with results reported at the 12-month and 18-month time periods for the same patients. The average age of Patients 4-6 at the two year timepoint was 10.4 years. Data from Patients 4-6 suggested sustained motor function at two years post-infusion, as assessed by 6MWT and NSAA, against expected natural history declines. In addition, the data suggested improved pulmonary function, as measured by FVC and PEF, and sustained or improved PROMs as assessed in key functional domains of the PODCI when compared to both baseline and natural history. In March 2022, we also reporteddata from skeletal muscle biopsies collected three months after infusion of SGT-001 from the most recently dosed Patients 7-9. The range by immunofluorescence of 1% to 50% and

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by western blot of Below the 5% Limit of Quantification (BLQ) to 6.8%, were within the range of previously dosed Patients 4-6 in the high dose cohort. Microdystrophin expression levels for all six patients dosed in the high dose cohort (Patients 4-9) ranged from 1 to 70% by immunofluorescence and BLQ to 17.5% by western blot. All six patients dosed with SGT-001 in the high dose cohort have demonstrated microdystrophin expression and proper membrane localization.

No new drug-related safety findings have been identified in Patients 1-9 in post-dosing periods of 90 days to approximately four years. We continue to follow dosed patients and collect data to support the potential benefit of SGT-001.

SGT-003 is our next-generation gene transfer candidate. It is comprised of our nNOS binding domain microdystrophin transgene and muscle-specific promoter present in SGT-001 and uses a lead candidate novel, rationally designed AAV capsid, developed for enhanced muscle tropism, to deliver these components to target tissues. We believe that the properties of this novel capsid may allow for enhanced benefit over therapies using traditional capsids, potentially both in terms of efficacy and safety.

We intend to initiate IND-enabling studies for SGT-003 in 2022 to support a planned IND submission in early 2023.

In addition to our gene transfer candidates, we have development programs focusing on platform technologies, including dual gene expression, a technology that allows us to package multiple transgenes into one vector, as well as novel capsids. These programs are part of our ongoing research efforts to develop innovative technologies that we believe may hold potential to translate into meaningful treatments and drive our future pipeline expansion. Preclinical data in both wild-type and disease animal models demonstrate that we have developed a library of novel capsids that have shown increased muscle tropism with concomitant decreased liver biodistribution resulting in improved efficiency compared with AAV9.

Since our inception, we have devoted substantial resources to identifying and developing SGT-001, SGT-003 and our other product candidates, developing our manufacturing processes, organizing and staffing our company and providing general and administrative support for these operations. We have incurred significant losses every year since our inception. We do not have any products approved for sale. To date, we have not generated any revenue from product sales. Our ability to eventually generate any product revenue sufficient to achieve profitability will depend on the successful development, approval and eventual commercialization of SGT-001, SGT-003 and our other product candidates. If successfully developed and approved, we intend to commercialize SGT-001 and SGT-003 in the United States and European Union and may enter into licensing agreements or strategic collaborations in other markets. If we generate product sales or enter into licensing agreements or strategic collaborations, we expect that any revenue we generate will fluctuate from quarter to quarter and year to year as a result of the timing and amount of any product sales, license fees, milestone payments and other payments. If we fail to complete the development of SGT-001, SGT-003 and our other product candidates in a timely manner or obtain regulatory approval of them, our ability to generate future revenue, and our results of operations and financial position, would be materially adversely affected.

Due to our significant research and development expenditure, licensing and patent investment, and general administrative costs associated with our operations, we have generated substantial operating losses in each period since our inception. Our net losses were $72.2 million, $88.3 million and $117.2 million for the years ended December 31, 2021, 2020 and 2019, respectively. As of December 31, 2021, we had an accumulated deficit of $476.8 million. We expect to incur significant expenses and operating losses for the foreseeable future.

In January 2020, we announced a reduction in workforce by approximately 30% as part of a strategic plan designed to create a leaner company focused on advancing SGT-001.

As we seek to develop and commercialize SGT-001, SGT-003 or any other product candidates, we anticipate that our expenses will increase significantly and that we will need substantial additional funding to support our continuing operations. Until such time as we can generate significant revenue from product sales, if ever, we expect to finance our operations through a combination of public or private equity financings, debt financings or other sources, which may include licensing agreements or strategic collaborations. We may be unable to raise additional funds or enter into such agreements or arrangements when needed on favorable terms, if at all. If we fail to raise capital or enter into such agreements as and when needed, we may have to significantly delay, scale back or discontinue the development or commercialization of SGT-001, SGT-003 or our other product candidates.

Because of the numerous risks and uncertainties associated with product development, we are unable to predict the timing or amount of increased expenses or determine when or if we will be able to achieve or maintain profitability. Even if we are able to generate revenue from product sales, we may not become profitable. If we fail to become profitable or are unable to sustain profitability on a continuing basis, then we may be unable to continue our operations at planned levels and be forced to reduce or terminate our operations.

In October 2020, we entered into a collaboration and license agreement, or the Collaboration Agreement, with Ultragenyx Pharmaceutical Inc., or Ultragenyx, pursuant to which we granted Ultragenyx an exclusive worldwide license

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under certain intellectual property rights controlled by us to make, have made, use, distribute, offer for sale, sell, import and export, including to research, develop, modify, enhance, improve, register, distribute, commercialize, or otherwise dispose of AAV8 or other clade E AAV variant pharmaceutical products that express our MD5 nNOS binding domain form of microdystrophin protein for the diagnosis, treatment, cure, mitigation or prevention of Duchenne and other disease indications resulting from a lack of functional dystrophin, including Becker muscular dystrophy. On a product-by-product basis, we have the option to fund 30% of the development costs in the United States and European Union and share 30% of the net income and net losses on net sales of such Licensed Product in the United States and European Union. In connection with the execution of the Collaboration Agreement, we also entered into a stock purchase agreement with Ultragenyx, pursuant to which we issued and sold 7,825,797 shares of our common stock to Ultragenyx for an aggregate purchase price of approximately $40 million.

During the year ended December 31, 2020, we sold 6,309,632 shares pursuant to an “at-the-market offering” sales agreement, dated March 13, 2019, or the ATM Sales Agreement, by and between us and Jefferies LLC, or Jefferies, resulting in net proceeds of $23.2 million.

In December 2020, we completed a private placement of shares of common stock resulting in net proceeds to us of $86.2 million, after deducting offering costs.

In March 2021, we issued and sold in a public offering 25,000,000 shares of our common stock at a price per share to the public of $5.75, including the full exercise by the underwriters of an option to purchase additional shares of common stock. We received net proceeds of approximately $134.9 million after deducting underwriter discounts and commissions and offering expenses.

As of December 31, 2021, we had cash, cash equivalents, and available-for-sale securities of $207.8 million. We believe that our cash, cash equivalents, and available-for-sale securities as of December 31, 2021 will enable us to fund our operating expenses and capital expenditure requirements into the third quarter of 2023. 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.

The ongoing COVID-19 pandemic has caused federal, state, and local governments to implement measures to slow the spread of the outbreak through quarantines, strict travel restriction and bans, heightened border scrutiny and other measures. We are following, and will continue to follow, recommendations from the U.S. Centers for Disease Control and Prevention as well as federal, state, and local governments regarding working-from-home practices for non-essential employees. As a result, we have modified our business practices, including implementing a work from home policy for all employees who are able to perform their duties remotely. We expect to continue to take actions as may be required or recommended by government authorities or as we determine are in the best interests of our employees, and other business partners in light of COVID-19. The full extent of the impact of COVID-19 on our business, results of operations and financial condition will depend on future developments that are highly uncertain, including the length and severity of this pandemic, the actions taken to contain it or treat its impact and the impact on our clinical development, employees, vendors and suppliers, all of which are uncertain and cannot be predicted. We will continue to monitor the situation closely.

Financial operations overview

Revenue

Collaboration revenue

Collaboration revenue was $13.6 million for the year ended December 31, 2021. We recognized this revenue related to research services and cost reimbursement from the Collaboration Agreement. There was no revenue in the year ended December 31, 2020.

Product revenue

We have not generated any product revenue to date and do not expect to generate any product revenue from the sale of our products for the foreseeable future, if ever. If our development efforts for SGT-001, SGT-003 or our other product candidates are successful and result in marketing approval, we may generate product revenue in the future from product sales.

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Operating expenses

We classify our operating expenses into two categories: research and development, and general and administrative expenses. Personnel costs, including salaries, benefits, bonuses and equity-based compensation expense, comprise a significant component of each of these expense categories. We allocate expenses associated with personnel costs based on the nature of work associated with these resources.

Research and development expenses

Research and development expenses consist primarily of costs incurred for our research activities, including our discovery efforts, and the development of SGT-001, SGT-003 and our other product candidates and include:

• expenses incurred under our intellectual property licenses; and

We expense research and development costs as incurred. We recognize costs for certain development activities, such as preclinical research and development and clinical trial costs, based on an evaluation of the progress to completion of specific tasks using information and data provided to us by our vendors, collaborators and third-party service providers. Payments for these activities are based on the terms of the individual agreements, which may differ from the pattern of costs incurred, and are reflected in our consolidated financial statements as prepaid or accrued research and development expenses.

We typically use our employee and infrastructure resources across our product candidates. We track outsourced development costs and milestone payments made under our licensing arrangements by product candidates, but we do not allocate personnel costs, license payments made under our licensing arrangements or other internal costs to product candidates on a program-specific basis. These costs are included in unallocated research and development expenses in the table below.

The following table summarizes our research and development expenses by product candidates for the respective periods:

For the Year Ended December 31,

Unallocated research and development expenses

Total unallocated research and development expenses 34,965 32,241

Total research and development expenses $ 58,739 $ 64,881

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We cannot determine with certainty the duration, costs and timing of clinical trials of SGT-001 and our other product candidates, including SGT-003, or if, when or to what extent we will generate revenue from the commercialization and sale of any of our product candidates for which we obtain marketing approval or our other research and development expenses. We may never succeed in obtaining marketing approval for any of our product candidates. The duration, costs and timing of clinical trials and development of our product candidates will depend on a variety of factors, including:

• significant and changing government regulation and regulatory guidance;

• the timing and receipt of any marketing approvals; and

Research and development activities are central to our business model. Product candidates in later stages of clinical development generally have higher development costs than those in earlier stages of clinical development, primarily due to the increased size and duration of later-stage clinical trials.We expect that our research and development expenses will continue to increase for the foreseeable future as we proceed with clinical trials for SGT-001, initiate clinical trials for SGT-003 and other product candidates and continue to identify and develop additional product candidates.

General and administrative expenses

General and administrative expenses consist primarily of salaries and other related costs, including equity-based compensation, for personnel in our executive, finance, business development and administrative functions. General and administrative expenses also include legal fees relating to patent and corporate matters, professional fees for accounting, auditing, tax and consulting services, insurance costs, travel expenses, and facility-related expenses, which include direct depreciation costs and allocated expenses for rent and maintenance of office facilities and other operating costs.

We expect that our general and administrative expenses will increase in the future as we increase our general and administrative personnel headcount to support our research and development activities and activities related to the potential commercialization of SGT-001 and our other product candidates, including SGT-003.

Restructuring charges

In January 2020, we implemented changes to our organizational structure to create a leaner company focused on advancing SGT-001. In connection with the restructuring, we made changes to our management team and reduced headcount by approximately 30 percent.

Other income (expense), net

Other income (expense), net consists of interest income earned on our cash, cash equivalents, and available-for-sale securities, and funding from charitable organizations, net of financing leases interest expense.

Income taxes

We account for income taxes using an asset and liability approach, which requires recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the consolidated financial statements but have not been reflected in taxable income. A valuation allowance is established to reduce deferred tax assets to their estimated realizable value.

We account for uncertainty in income taxes recognized in the financial statements by applying a two-step process to determine the amount of tax benefit to be recognized. First, the tax position must be evaluated to determine the likelihood

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that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more-likely-than-not to be sustained, the tax position is then assessed to determine the amount of benefit to recognize in the financial statements. The amount of the benefit that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. The provision for income taxes includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties.

Critical accounting policies and use of estimates

Our management’s discussion and analysis of financial condition and results of operations is based on our consolidated financial statements, which have been prepared in accordance with generally accepted accounting principles in the United States. The preparation of our consolidated financial statements and related disclosures requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, costs and expenses and the disclosure of contingent assets and liabilities in our consolidated financial statements. We base our estimates on historical experience, known trends and events and various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. We evaluate our estimates and assumptions on an ongoing basis. Our actual results may differ from these estimates.

While our significant accounting policies are described in more detail in the notes to our consolidated financial statements appearing at the end of this Annual Report on Form 10-K, we believe that the following accounting policies are those most critical to the judgments and estimates used in the preparation of our consolidated financial statements.

Revenue Recognition

As discussed in Note 2 to our consolidated audited financial statements, under Accounting Standards Codification, or ASC, 606, Revenue from Contracts with Customers , an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services.

To determine the appropriate amount of revenue to be recognized for arrangements determined to be within the scope of ASC 606, we perform the following five steps: (i) identification of the contract(s) with the customer, (ii) identification of the promised goods or services in the contract and determination of whether the promised goods or services are performance obligations, (iii) measurement of the transaction price, (iv) allocation of the transaction price to the performance obligations, and (v) recognition of revenue when (or as) we satisfy each performance obligation. We only apply the five-step model to contracts when it is probable that the entity will collect consideration it is entitled to in exchange for the goods or services it transfers to the customer.

When optional goods or services are offered, we assess the options to determine whether the options grant the customer a material right. This determination includes whether the option is priced at an amount that the customer would not have received without entering into the contract. If we conclude the option conveys a material right, it is accounted for as a separate performance obligation. In identifying performance obligations in a contract, we identify those promises that are distinct. Promised goods or services are considered distinct when the customer can benefit from the goods or services on their own, or together with readily available resources, and the goods or services are separately identifiable from other promises in the contract. If a promise is not distinct, it is combined with other promises in the contract until the combined group of promises is capable of being distinct.

We estimate the transaction price based on the amount of consideration we expect to receive for transferring the promised goods or services in the contract. The consideration may include both fixed consideration and variable consideration. At the inception of each arrangement that includes variable consideration, we evaluate the amount of the potential payments and the likelihood that the payments will be received. If it is probable that a significant revenue reversal would not occur, the variable consideration is included in the transaction price. For contracts that include sales-based royalties for licensed compounds, we recognize revenue at the date when the related sales occur. Finally, we determine whether the contract contains a significant financing component by analyzing the promised consideration relative to the standalone selling price of the promised goods and services and the timing of payment relative to the transfer of the promised goods and services. At each reporting date, we reassess the transaction price and probability of achievement of the performance obligations and the associated constraints on transaction price. If necessary, we adjust the transaction price, recording a cumulative catch-up based on progress for the amount that was previously constrained.

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Revenue is recognized when (or as) control of a performance obligation is transferred to the customer. When combined performance obligations contain a promised license and related services or other promises, management judgment is required to determine the appropriate timing of revenue recognition. In doing so, we must identify the predominant promise or promises in the contract to determine whether revenue is recognized at a point in time or over time. If over time, we must determine the appropriate measure of progress. If a license is deemed to be the predominant promise in a performance obligation, we must determine the nature of the license, whether functional or symbolic intellectual property, to conclude whether point-in-time or over-time revenue recognition is most appropriate. The determination of functional or symbolic intellectual property requires an assessment of whether the customer is able to exploit and benefit from the license in its current condition, or if the utility of the license is dependent on or influenced by our ongoing activities or being associated with us.

At each reporting date, we calculate the measure of progress for the performance obligations transferred over time. The calculation generally uses an input measure based on costs incurred to-date relative to estimated total costs to complete the transfer of the performance obligation. The measurement of progress is then used to calculate the total revenue earned, including any cumulative catch-up adjustment. A 10% increase or decrease in the transaction price impacts net revenues from collaborators by a corresponding increase or decrease of approximately $1.3 million. A 10% increase or decrease in the total forecasted costs to be incurred over the period the transfer of goods or services occurs impacts net revenues from collaborators by a corresponding decrease or increase of approximately $0.5 million.

Accrued research and development expenses

As part of the process of preparing our consolidated financial statements, we are required to estimate our accrued research and development expenses. This process involves reviewing open contracts and purchase orders, communicating with our personnel to identify services that have been performed on our behalf and estimating the level of service performed and the associated costs incurred for the services when we have not yet been invoiced or otherwise notified of the actual costs. The majority of our service providers invoice us in arrears for services performed, on a pre-determined schedule or when contractual milestones are met; however, some require advanced payments. We make estimates of our accrued expenses as of each balance sheet date in our consolidated financial statements based on facts and circumstances known to us at that time. Examples of estimated accrued research and development expenses include fees paid to:

• vendors in connection with preclinical development activities;

• third parties under our intellectual property licenses.

We base our expenses related to preclinical studies and clinical trials on our estimates of the services received and efforts expended pursuant to quotes and contracts with multiple CROs that conduct and manage preclinical studies and clinical trials on our behalf. The financial terms of these agreements are subject to negotiation, vary from contract to contract and may result in uneven payment flows. There may be instances in which payments made to our vendors will exceed the level of services provided and result in a prepayment of the expense. In accruing fees, we estimate the time period over which services will be performed, and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from our estimate, we adjust the accrual or amount of prepaid expense accordingly. Although we do not expect our estimates to be materially different from amounts actually incurred, our understanding of the status and timing of services performed relative to the actual status and timing of services performed may vary and could result in us reporting amounts that are too high or too low in any particular period.

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Equity-based compensation

In connection with the completion of our initial public offering, we adopted the 2018 Omnibus Incentive Plan, or the 2018 Plan, which provides for the issuance of share-based awards, including options to purchase common stock. The 2018 Plan provides for the awarding of up to 5,001,000 shares of common stock for equity awards. On June 16, 2020, our stockholders approved the 2020 Equity Incentive Plan, or the 2020 Plan, which consists of (i) 3,000,000 shares of common stock and (ii) additional shares of common stock (up to 4,879,025) as is equal to (i) the number of shares reserved under the 2018 Plan that remained available for grant under the 2018 Plan as of immediately prior to the date the 2020 Plan was approved by our stockholders and (ii) the number of shares subject to awards granted under the 2018 Plan which awards expire, terminate or are otherwise surrendered, cancelled, forfeited or repurchased by us at their original issuance price pursuant to a contractual repurchase right. On June 16, 2021, our stockholders approved an amendment to the 2020 Plan to reserve an additional 7,000,000 shares of common stock for issuance under the plan. Under the 2020 Plan, stock options may not be granted at less than fair value on the date of grant. At December 31, 2021, 8,557,152 shares remained available for future issuance under the 2020 Plan.

In June 2021, the Company’s stockholders also approved the 2021 Employee Stock Purchase Plan, or the ESPP, which provides for 1,102,885 shares to be available for purchase by eligible employees according to its terms. At December 31, 2021, 1,058,204 shares remained available for future issuance under the ESPP.

We measure all stock options and other stock-based awards granted to employees, directors and non-employees based on the fair value on the date of the grant and recognize compensation expense of those awards, over the requisite service period, which is generally the vesting period of the respective award. Forfeitures are accounted for as they occur. We apply the straight-line method of expense recognition to all awards with only service-based vesting conditions. We have not issued any awards with performance-based vesting conditions. For stock-based awards granted to non-employees, compensation expense is recognized over the period during which services are rendered by such non-employees until completed.

The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model. We historically have been a private company and lack company-specific historical and implied volatility information. Therefore, we estimate our expected stock volatility based on the historical volatility of a publicly traded set of peer companies and expect to continue to do so until such time as we have adequate historical data regarding the volatility of our own traded stock price. For options with service-based vesting conditions, the expected term of our stock options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. Through December 31, 2018, the expected term of stock options granted to non-employees is equal to the contractual term of the option award and effective January 1, 2019, the “simplified” method is used. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is based on the fact that we have never paid cash dividends and do not expect to pay any cash dividends in the foreseeable future, if ever.

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Results of operations

Comparison of the years ended December 31, 2021 and 2020

The following table summarizes our results of operations for the years ended December 31, 2021 and 2020:

For the Year Ended December 31, Increase %

(in thousands)

Operating expenses:

Other income (expense):

Total other income (expense) 66 116 (50 ) (43 )%

Collaboration revenue

Collaboration revenue for the year ended December 31, 2021 was $13.6 million, compared to no collaboration revenue for the year ended December 31, 2020. The increase in collaboration revenue was related to research services and cost reimbursement received under the Collaboration Agreement with Ultragenyx, which we entered into in the fourth quarter of 2020.

Research and development expenses

For the Year Ended December 31, Increase %

(in thousands)

Unallocated research and development expenses

Research and development costs for the year ended December 31, 2021 were $58.7 million, compared to $64.9 million for the year ended December 31, 2020. The decrease of $6.1 million in research and development costs was due to a decrease in SGT-001 research and development costs of $6.7 million primarily due to the impacts of COVID-19, and a decrease of SGT-003 and other product candidates costs of $2.2 million primarily due to license fees incurred in 2020 in conjunction with the UltragenyxCollaboration agreement. This was partially offset by an increase in unallocated expenses of $2.7 million primarily driven by personnel related expenses from an increase in headcount in 2021.

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General and administrative expenses

General and administrative expenses were $27.1 million for the year ended December 31, 2021, compared to $21.6 million for the year ended December 31, 2020. The increase of $5.5 million was due to an increase in personnel related expenses of $4.1 million due to the increase in headcount in 2021 and an increase in consulting fees of $1.4 million.

Restructuring charges

During the year ended December 31, 2021 we recorded no expense related to restructuring compared to $1.9 million of restructuring charges as of December 31, 2020. The restructuring charges related to severance and other employee-related costs in connection with the restructuring that occurred in January 2020. We paid approximately $1.8 million during the year ended December 31, 2020 and $0.1 million during the year ended December 31, 2021.

Interest income

Interest income was $0.1 million and $0.1 million for the years ended December 31, 2021 and 2020, respectively. There was no change as the portfolio of available-for-sale securities remained consistent.

Other income

Other income relates to contributions from charitable organizations. We do not expect these contributions to reoccur in future periods.

Results of Operations—Years Ended December 31, 2020 and 2019

Discussion and analysis of the year ended December 31, 2020 compared to the year ended December 31, 2019 is included in Part II, Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations” in our Annual Report on Form 10-K for the year ended December 31, 2020 as filed with the SEC on March 15, 2021 (“2020 Form 10-K”).

Liquidity and capital resources

Sources of liquidity

To date, we have financed our operations primarily through the sale of redeemable preferred units and member units, the sale of common stock and prefunded warrants to purchase shares of our common stock in private placements and the sale of common stock in our initial public offering and a follow-on public offering. Through December 31, 2021, we raised an aggregate of $144.6 million of gross proceeds from our sales of preferred units prior to the completion of our initial public offering, and an aggregate of $471.3 million of net proceeds from the sale of our common stock through public offerings, including our IPO, our ATM Sales Agreement, private placements including the stock purchase agreement with Ultragenyx, as detailed in the following paragraphs.

On July 30, 2019, we issued and sold in a private placement (i) 10,607,525 shares of our common stock at a price per share of $4.65 and (ii) 2,295,699 pre-funded warrants to purchase shares of our common stock at a price per warrant of $4.64. Each pre-funded warrant is exercisable for one share of common stock at an exercise price of $0.01 and the pre-funded warrants have no expiration date. We received $57.9 million of net proceeds from the private placement after deducting offering costs. On October 2, 2020, 137,460 of these pre-funded warrants were exercised.

On October 22, 2020, we entered into the Collaboration Agreement with Ultragenyx. In connection with the execution of the Collaboration Agreement, we also entered into a stock purchase agreement with Ultragenyx, pursuant to which we issued and sold 7,825,797 shares of our common stock to Ultragenyx for an aggregate purchase price of approximately $40 million.

On December 15, 2020, we issued and sold in a private placement 24,324,320 shares of our common stock at a price per share of $3.70. We received $86.2 million of net proceeds from the private placement after deducting offering costs.

On March 13, 2019, we entered into the ATM Sales Agreement, which was amended in August 2021, under which we may offer and sell, from time to time, shares of our common stock having aggregate gross proceeds of up to $75.0 million through Jefferies as sales agent. Any such sales being made by any method that is deemed an “at-the-market offering” as defined in Rule 415 promulgated under the Securities Act. We will pay Jefferies a commission of up to 3% of the gross

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proceeds of any sales of common stock pursuant to the ATM Sales Agreement. During the year ended December 31, 2020, we sold 6,309,632 shares pursuant to the ATM Sales Agreement resulting in net proceeds of $23.2 million.During the year ended December 31, 2021, we did not sell any shares pursuant to the ATM Sales Agreement

On March 23, 2021, we issued and sold in a public offering 25,000,000 shares of our common stock at a price per share of $5.75, including the full exercise by the underwriters of an option to purchase additional shares of common stock, or the March 2021 Offering. We received net proceeds of approximately $134.9 million after deducting underwriter discounts and commissions and offering expenses.

As of December 31, 2021, we had cash, cash equivalents and available-for-sale securities of $207.8 million and had no debt outstanding.

Cash flows

The following table summarizes our sources and uses of cash for each of the periods presented:

For the Year Ended December 31,

(in thousands)

Cash used in operating activities $ (77,764 ) $ (56,599 )

Cash (used in) provided by investing activities (91,086 ) 6,600

Net (decrease) increase in cash and cash equivalents $ (33,865 ) $ 78,701

Operating activities

During the year ended December 31, 2021,operating activities used $77.8 million of cash, primarily resulting from our net loss of $72.2 million offset by non-cash charges of $17.5 million due primarily to equity-based compensation of $13.4 million and depreciation expense of $3.0 million and marketable securities of $1.1 million. Net cash used by changes in our operating assets and liabilities was $23.1 million which included a decrease in deferred revenue of $12.6 million and an increase in accounts receivable of $0.1 million as a result of the Ultragenyx Collaboration Agreement, a decrease in prepaid and other non-current assets of $9.3 million and a decrease in accrued other liabilities and non-current liabilities of $2.3 partially offset by an increase in accounts payable of $1.2 million due to the timing of payments.

During the year ended December 31, 2020,operating activities used $56.6 million of cash, primarily resulting from our net loss of $88.3 million offset by non-cash charges of $15.5 million due primarily to equity-based compensation of $11.6 million and depreciation expense of $3.9 million as well as cash provided by changes in our operating assets and liabilities. Net cash provided by changes in our operating assets and liabilities included a decrease in accounts payable, accrued expenses and non-current liabilities of $4.6 million due to the timing of payments and an increase in deferred revenue of $20.8 million as a result of the Ultragenyx Collaboration Agreement. Net cash provided by changes in our operating assets and liabilities also consisted primarily of an increase in prepaid expenses and other assets of $0.1 million which was primarily due to an increase in prepayments related to research and development activities.

Investing activities

During the year ended December 31, 2021, investing activities used $91.1 million of cash, consisting primarily of net purchases of available-for-sale securities of $141.2 million and the purchase of property and equipment of $1.3 million partially offset by the sale of available-for-sale securities of $51.4 million.

During the year ended December 31, 2020, investing activities provided $6.6 million of cash, consisting primarily of net proceeds on the sale and maturity of available-for-sale securities partially offset by purchases of property and equipment.

Financing activities

During the year ended December 31, 2021, net cash provided by financing activities was $135.0 million as a result of the March 2021 Offering.

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During the year ended December 31, 2020, net cash provided by financing activities was $128.7 million, due to the net proceeds from our private placement of shares of our common stock that we completed in December 2020 and sales under the ATM Sales Agreement as well as proceeds from the issuance of common stock to Ultragenyx.

A discussion of changes in our cash flow from the year ended December 31, 2019 to the year ended December 31, 2020 can be found in Part II, Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations” of the 2020 Form 10-K.

Funding requirements

We expect our expenses to increase substantially in connection with our ongoing development activities related to SGT-001, SGT-003 and our other product candidates. In addition, we have incurred and expect to continue to incur additional costs associated with operating as a public company. We expect that our expenses will increase substantially if and as we:

• move SGT-003 or our other product candidates into clinical trials;

• seek to identify additional product candidates;

• maintain, expand, protect and enforce our intellectual property portfolio;

• hire and retain additional clinical, quality control and scientific personnel;

• acquire or in-license other drugs, technologies and intellectual property;

• add operational, financial and management information systems and personnel.

As of December 31, 2021, we had cash, cash equivalents and available-for-sale securities of $207.8 million. We believe that our existing cash, cash equivalents and available-for-sale securities as of December 31, 2021 will be sufficient to fund our operating expenses and capital requirements into the third quarter of 2023. As a result, 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 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.

Because of the numerous risks and uncertainties associated with the development of SGT-001, SGT-003 and other product candidates and programs and because the extent to which we may enter collaborations with third parties for development of our product candidates is unknown, we are unable to estimate the timing and amounts of increased capital outlays and operating expenses associated with completing the research and development of our product candidates. Our future capital requirements will depend on many factors, including:

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• the outcome of any lawsuits filed against us;

• the terms of our current and any future license agreements and collaborations;

• the success of our collaboration with Ultragenyx;

We are supplying, and expect to continue to supply, our clinical development program for SGT-001 with drug product produced at a cGMP compliant facility located at one of our CDMO partners. We intend to establish the capability and capacity to supply SGT-001 at commercial scale from multiple sources.

Developing pharmaceutical products, including conducting preclinical studies and clinical trials, is a time-consuming, expensive and uncertain process that takes years to complete, and we may never generate the necessary data or results required to obtain marketing approval for any product candidates or generate revenue from the sale of any products for which we may obtain marketing approval. In addition, our product candidates, if approved, may not achieve commercial success. Our commercial revenues, if any, will be derived from sales of products that we do not expect to be commercially available for many years, if ever. Accordingly, we will need to obtain substantial additional funds to achieve our business objectives.

Adequate additional funds may not be available to us on acceptable terms, or at all. We do not currently have any committed external source of funds. To the extent that we raise additional capital through the sale of equity securities, our existing stockholders’ ownership interest may be diluted. Any debt or preferred equity financing, if available, may involve agreements that include restrictive covenants that may limit our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends, which could adversely impact our ability to conduct our business, and may require the issuance of warrants, which could potentially dilute existing stockholders’ ownership interests.

If we raise additional funds through licensing agreements and strategic collaborations with third parties, we may have to relinquish valuable rights to our technology, future revenue streams, research programs, or product candidates or grant licenses on terms that may not be favorable to us. If we are unable to raise additional funds, we may be required to delay, limit, reduce and/or terminate development of our product candidates or any future commercialization efforts or grant rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves.

Contractual obligations and commitments

We lease certain office space, lab space and lab equipment in Massachusetts. These leases are used for our continuing operations. For a description of the Company’s lease obligations, refer to Note 10 to our consolidated financial statements appearing at the end of this Annual Report on Form 10-K.

We will lease our new corporate headquarters starting in May 2022, which consists of approximately 49,869 square feet of office, laboratory, research and development and manufacturing space in Charlestown, Massachusetts. The lease for our new corporate headquarters has an initial term of approximately ten years that expires in 2032 with an option to extend the lease for an additional five years.

We enter into contracts in the normal course of business with CROs and CMOs for clinical trials, preclinical research studies and testing, manufacturing and other services and products for operating purposes. These contracts are cancelable by us upon prior notice of 30 days.

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Unconditional purchase commitments of $0.8 million represent minimum payments due within a year to purchase goods that are enforceable and legally binding and that specify all significant terms, including fixed or minimum quantities to be purchased, fixed or variable price provisions, and the approximate timing of the transaction.

Recently issued accounting pronouncements

We have reviewed all recently issued standards and have determined that, other than as disclosed in Note 2 to our consolidated financial statements appearing at the end of this Annual Report on Form 10-K, such standards will not have a material impact on our consolidated financial statements or do not otherwise apply to our operations.

Emerging growth company status

The JOBS Act permits an emerging growth company such as us to take advantage of an extended transition period to comply with new or revised accounting standards applicable to public companies until those standards would otherwise apply to private companies. We have irrevocably elected to opt out of this provision and, as a result, we will comply with new or revised accounting standards when they are required to be adopted by public companies that are not emerging growth companies.

Item 7A. Quantitative and Qualitative Disclosures About Market Risk.

Interest Rate Risk

We are exposed to market risk related to changes in interest rates. As of December 31, 2021, our cash equivalents consisted of money market accounts that have contractual maturities of less than 90 days from the date of acquisition. As of December 31, 2021, our investments consisted of corporate bond securities that have contractual maturities of less than one year. Our primary exposure to market risk is interest income sensitivity, which is affected by changes in the general level of U.S. interest rates. However, because of the short-term nature of our portfolio, an immediate 10% change in market interest rates would not have a material impact on the fair market value of our investment portfolio or on our financial position or results of operations.

Inflation Risk

We do not believe that inflation had a material effect on our business, financial condition or results of operations in the last three years.

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Item 8. Financial Statements and Supplementary Data.

The information required by this Item 8 is included at the end of this Annual Report on Form 10-K beginning on page F-1.

Not applicable.

Item 9A. Controls and Procedures.

Evaluation of Disclosure Controls and Procedures

Our management, with the participation of our Chief Executive Officer and Interim Chief Financial Officer (our principal executive officer and principal financial officer, respectively), evaluated the effectiveness of our disclosure controls and procedures as of December 31, 2021. The term "disclosure controls and procedures," as defined in Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934, as amended, or the Exchange Act, refers to controls and other procedures of a company that are designed to ensure that information required to be disclosed by a company in the reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported, within the time periods specified in the SEC's rules and forms. Disclosure controls and procedures include, without limitation, controls and procedures designed to ensure that such information required to be disclosed by a company in the reports that it files or submits under the Exchange Act is accumulated and communicated to a company's management, including its principal executive and principal financial officers, or persons performing similar functions, as appropriate to allow timely decisions regarding required disclosure.

In designing and evaluating our disclosure controls and procedures, management recognizes that disclosure controls and procedures, no matter how well designed and operated, can provide only reasonable, not absolute, assurance that the objectives of the disclosure controls and procedures are met. Additionally, in designing disclosure controls and procedures, our management necessarily was required to apply its judgment in evaluating the cost-benefit relationship of possible disclosure controls and procedures. The design of any system of controls also is based in part upon certain assumptions about the likelihood of future events, and there can be no assurance that any design will succeed in achieving its stated goals under all potential future conditions; over time, controls may become inadequate because of changes in conditions, or the degree of compliance with policies or procedures may deteriorate. Because of the inherent limitations in a control system, misstatements due to error or fraud may occur and not be detected.

Based on the evaluation of our disclosure controls and procedures, our Chief Executive Officer and Interim Chief Financial Officer concluded that, as of December 31, 2021, our disclosure controls and procedures were effective at the reasonable assurance level.

Management's Annual Report on Internal Control over Financial Reporting

Our management is responsible for establishing and maintaining adequate internal control over financial reporting as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act. Our internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Management conducted an evaluation of the effectiveness of our internal control over financial reporting as of December 31, 2021 based on the framework in Internal Control-Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO). Based on that evaluation, management has concluded that the Company's internal control over financial reporting was effective as of December 31, 2021.

This Annual Report on Form 10-K does not include an attestation report of our independent registered public accounting firm due to a transition period established by rules of the SEC for “emerging growth companies”.

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Changes in Internal Control over Financial Reporting

There have been no changes in our internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) that occurred during the three months ended December 31, 2021 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

Item 9B. Other Information.

Not applicable.

Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections.

Not applicable.

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PART III

Item 10. Directors, Executive Officers and Corporate Governance.

Set forth below are the names, ages and positions of our current executive officers and directors as of March 14, 2022.

Name Age Position(s) held

Executive Officers

Ilan Ganot 48 Co-founder, President, Chief Executive Officer and Director

Stephen DiPalma 63 Interim Chief Financial Officer and Treasurer

Erin Powers Brennan 51 Chief Legal Officer

Carl Morris, Ph.D. 52 Chief Scientific Officer

Joel Schneider, Ph.D. 37 Chief Operating Officer

Non-Employee Directors

Ian Smith 55 Executive Chairman of the Board of Directors

Martin Freed, M.D., F.A.C.P. 61 Director

Robert Huffines 56 Director

Clare Kahn, Ph.D 70 Director

Georgia Keresty, Ph.D, M.PH. 60 Director

Adam Koppel, M.D., Ph.D. 52 Director

Sukumar Nagendran, M.D. 56 Director

Rajeev Shah 44 Director

Adam Stone 42 Director

Lynne Sullivan 55 Director

Executive officers

Ilan Ganot is one of our founders and has served as our Chief Executive Officer and as a member of our Board of Directors since our inception in 2013. Mr. Ganot has served as our President since June 2018. Previously, Mr. Ganot served as an investment banker at JPMorgan Chase & Co., a leading global financial services firm, from September 2011 to September 2013. From October 2008 to August 2011, Mr. Ganot served as a banker at Nomura Securities Co., Ltd., a securities and investment banking company, and from September 2003 to September 2008, at Lehman Brothers, a global financial services firm. Mr. Ganot received his M.B.A. from London Business School and holds law and business degrees from the Interdisciplinary Center in Herzliya, Israel. Mr. Ganot also practiced corporate law in Israel and was a Captain in the Israeli Defense Forces. He is qualified to serve on our Board of Directors because of his personal dedication to improving treatments available for Duchenne patients and his extensive leadership experience.

Stephen DiPalmahas served as our Interim Chief Financial Officer and Treasurer since January 2021. He is currently a managing director of Danforth Advisors, LLC, a financial consultancy firm that specializes in working with life sciences companies. Prior to, and during his tenure at Danforth, Mr. DiPalma has served as Chief Financial Officer to a number of public companies, in addition to many private companies in various stages of development. Immediately prior to joining Danforth in 2014, he served as Chief Financial Officer at Forum Pharmaceuticals from 2009 to 2014. He holds a Bachelor of Science from the University of Massachusetts and a master’s in business administration from Babson College.

Erin Powers Brennanhas served as our Chief Legal Officer and Secretary since March 2021. Prior to joining Solid, she served as Senior Vice President, General Counsel and Secretary at Covetrus Inc., a publicly traded, global animal health pharmacy, technology, and services company from 2019 to 2020 and previously the General Counsel, Vets First Choice from 2018 to 2019, before it merged with Covetrus. Previously, she was a partner at Morgan, Lewis & Bockius, where she worked from 2013 to 2018. Ms. Brennan holds a J.D. from Boston College Law School, an M.A. in Law and Diplomacy from The Tufts University Fletcher School, and a B.A. in Government and Latin American Studies from Scripps College.

Carl Morris, Ph.D. has served as our Chief Scientific Officer since June 2017, and previously served as our Senior Vice President of Research and Development from September 2015 to June 2017. Prior to joining us, Dr. Morris held various leadership positions within Pfizer Inc.’s, or Pfizer’s, Rare Disease Research Unit from January 2010 to August 2015, including serving as a Senior Director, Director and Senior Principal Scientist. Prior to Pfizer, Dr. Morris held various positions within the Tissue Repair unit at Wyeth Pharmaceuticals, Inc., a pharmaceutical company acquired by Pfizer. Dr. Morris was an Assistant Professor at Boston University School of Medicine and a founding faculty member of the Muscle and Aging Research Unit. He is also co-founder and a member of the Board of Directors of Breed Nutrition Inc. Dr. Morris holds a B.A. in Biology from Franklin Pierce College and a Ph.D. in Physiology from UCLA.

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Joel Schneider, Ph.D. has served as our Chief Operating Officer since March 2021. Prior to this role, Dr. Schneider served as the Chief Technology Officer and Head of Exploratory Research and Development from 2017 to 2021. Dr. Schneider also served as an Analyst from March 2014 to March 2015, a Director from March 2015 to January 2017 and our Vice President of Research and Development from January 2017 to June 2017. Prior to joining us, Dr. Schneider completed a postdoctoral fellowship at Harvard University in the Department of Stem Cell and Regenerative Biology from January 2013 to 2014. He holds a Ph.D. in Cell Biology and Molecular Medicine from Rutgers University and a B.A. in Biology from Brandeis University.

Non-employee directors

Ian F. Smith is Executive Chairman of our Board and has served as a member of our Board of Directors since April 2020 and served as a consultant to us from February 2020 to December 2021. Mr. Smith currently serves as director and Executive Chair of the board of ViaCyte, Inc., and as a director of the board of AavantiBio, both private biotechnology companies. He is also a member of the Board of Foghorn Therapeutics, a public biotechnology company, and is a Senior Advisor to Bain Capital Life Sciences. Between 2001 and 2019, Mr. Smith served as Executive Vice President and Chief Operating Officer, and Chief Financial Officer at Vertex Pharmaceuticals, a public biotechnology company. He received a B.A. with honors in accounting and finance from Manchester Metropolitan University (UK). Mr. Smith is qualified to serve on our Board of Directors because of his more than 25 years of finance and broad operating experience for public companies in the biopharmaceutical industry.

Martin Freed, M.D., F.A.C.P., has served as a member of our Board of Directors since June 2018. Dr. Freed has served as an independent consultant to several private pharmaceutical, biotechnology, and healthcare companies, specializing in clinical and general pharmaceutical development and clinical and regulatory strategy since February 2015. He co-founded and served as chief medical officer of Civitas Therapeutics, Inc., a biopharmaceutical company acquired by Acorda, from December 2010 to October 2014, and as senior vice president, clinical development of Acorda from October 2014 through January 2015. He has also served as chief medical officer at Adnexus Therapeutics, Inc. (acquired by Bristol-Myers Squibb) and Vitae Pharmaceuticals, Inc. Dr. Freed spent nearly 14 years at GlaxoSmithKline and its predecessor, SmithKline Beecham Pharmaceuticals or SmithKline Beecham, where he served numerous roles including vice president, clinical development and medical affairs in the metabolism therapeutic area. Dr. Freed currently serves on the Board of Directors for Avilar Therapeutics, Inc. He previously served on the Board of Directors for Sojournix, Inc. and Dicerna Pharmaceuticals. Dr. Freed has been Board Certified in Internal Medicine, Nephrology and Clinical Pharmacology. He performed his internal medicine residency at Temple University Hospital and nephrology fellowship at Yale-New Haven Hospital. A Fellow of the American College of Physicians, Dr. Freed received a B.S. with distinction in biology from the University of Delaware and an M.D. from Pennsylvania State University’s College of Medicine. Dr. Freed is qualified to serve on our Board of Directors because of his extensive leadership experience, his public company board experience and his experience working in the healthcare sector.

Robert Huffines has served as a member of our Board of Directors since December 2013. Mr. Huffines joined J.P. Morgan, a leading global financial services firm, in 1991 and currently serves as the Global Chairman of Investment Banking, a position he has held since February 2017. Throughout his career at J.P. Morgan, Mr. Huffines has held various leadership positions, including serving as Co-Head of the Global Healthcare Investment Banking Group from 2002 to 2010 and Vice Chairman from 2011 to January 2017. Mr. Huffines received an M.B.A. from the University of Virginia and a B.A. from the University of North Carolina. Mr. Huffines is qualified to serve on our Board of Directors based on his over 25 years of experience advising healthcare companies and his leadership experience.

Clare Kahn, Ph.D. has served as a member of our Board of Directors since March 2021. Dr. Kahn has served as R&D Strategy Officer at X-VAX Technology Inc. (“X-VAX”), a biotechnology company developing vaccines against pathogens acquired by mucosal infection such as herpes, since October 2019. She served as Chief Regulatory and Preclinical Development Officer at X-VAX from October 2018 to October 2019. Dr. Kahn has also been the president of Clare Kahn Pharma Consulting LLC, through which she provides consulting services on regulatory strategy since June 2016. Dr. Kahn was previously Vice President, Worldwide Regulatory Strategy, Global Innovative Pharma at Pfizer from January 2014 to June 2016 and Vice President, Worldwide Regulatory Strategy, Specialty Care Business at Pfizer from June 2010 to December 2013. Prior to Pfizer, she was Vice President of Regulatory Affairs at GlaxoSmithKline from 1999 to 2010. Dr. Kahn has a Ph.D. in Biochemical Pharmacology from The Royal Postgraduate Medical School, London and served as Assistant Professor of Pharmacology and of Pathology and Laboratory Medicine at The University of Pennsylvania from 1981-1985. Dr. Kahn is qualified to serve on our Board of Directors because of her extensive leadership experience and her experience working in the healthcare sector.

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Georgia Keresty, Ph.D., M.PH. has served as a member of our Board of Directors since March 2021. Dr. Keresty has served as a senior advisor to Takeda R&D, a global research and development driven biopharmaceutical company, since 2021 and she also served as their R&D chief operating officer from 2017 to 2020. From 2003 to 2017 and from 1997 to 1999, she was an executive at Johnson & Johnson. From 1999 to 2003 and from 1983 to 1997, she held roles at Bristol-Myers Squibb Company and Novartis Pharmaceuticals Corporation, respectively. Dr. Keresty holds BSc degrees in Chemical Engineering and Computer Science from Clarkson University and Ramapo College of New Jersey, an M.S. degree in Information Systems from Pace University, an MBA in Operations Management from Rutgers University, a Ph.D. in Operations Management from Rutgers University, and an MPH in Global Health Leadership from the University of Southern California. Dr. Keresty currently serves on the Board of Directors of Commissioning Agents, Inc., Intellia Therapeutics, Inc. and Aspen Technology, Inc. Dr. Keresty is qualified to serve on our Board of Directors because of her extensive leadership experience and her experience working in the healthcare sector.

Adam Koppel, M.D., Ph.D., has served as a member of our Board of Directors since October 2017. Dr. Koppel rejoined Bain Capital, a global investment firm, in 2016 as a Managing Director of Bain Capital Life Sciences. He initially joined Bain Capital Public Equity in 2003 where he was a leader within the healthcare sector until mid-2014. During the period from mid-2014 to mid-2016, Dr. Koppel worked at Biogen Inc., or Biogen, a biotechnology company, where he served as EVP of Corporate Development and Chief Strategy Officer. Prior to joining Bain Capital in 2003, Dr. Koppel was an Associate Principal at McKinsey & Co., a management consulting firm, where he served a variety of healthcare companies. Dr. Koppel currently serves on the Board of Directors of Aptinyx Inc., Cerevel Therapeutics LLC, Foghorn Therapeutics Inc., and Cardurion Pharmaceuticals, LLC. He is a board observer of ViaCyte, Inc. Previously, Dr. Koppel served of the Board of Directors of Trevena, Inc., Dicerna Pharmaceuticals, and PTC Therapeutics, Inc. Dr. Koppel received an M.D. and Ph.D. in Neuroscience from the University of Pennsylvania School of Medicine. He also received an M.B.A. from The Wharton School at the University of Pennsylvania, where he was a Palmer Scholar. He graduated magna cum laude from Harvard University with an A.B. and A.M. in History and Science. Dr. Koppel is qualified to serve on our Board of Directors because of his extensive leadership experience, his public company board experience and his experience working in the healthcare sector.

Sukumar Nagendran, M.D., has served as a member of our Board of Directors since September 2018. Since February 2020, Dr. Nagendran has served as Chief Medical Officer and President of R&D at Jaguar Gene Therapy. Prior to that, he was most recently the Chief Medical Officer and Senior Vice President of AveXis Inc., a clinical-stage gene therapy company, or AveXis, from September 2015 to July 2018, prior to the company’s acquisition by Novartis. Prior to AveXis, Dr. Nagendran was Vice President of Medical Affairs of Quest Diagnostics, a provider of diagnostic information services, from March 2013 to September 2015. Prior to Quest Diagnostics, Dr. Nagendran held key leadership positions at Pfizer, Novartis, Daiichi Sankyo, and Reata Pharmaceuticals. Prior to moving to the biotech industry, Dr. Nagendran practiced internal medicine, with a focus on diabetes and cardiovascular disease. He is a Mayo Alumni Laureate and founding member of the Robert Wood Johnson Legacy Society. He is also the sponsor for the Fonseca-Nagendran Scholar award at the American Diabetes Association to enhance research in minority populations. Dr. Nagendran currently serves on the Board of Directors of SalioGen Therapeutics and Taysha Gene Therapy. Dr. Nagendran received his undergraduate degree in Biochemistry from Rutgers University and his M.D. from Rutgers Medical School and trained in Internal Medicine at Mayo Clinic, Rochester. Dr. Nagendran is qualified to serve on our Board of Directors because of his extensive leadership experience and his experience working in the healthcare sector.

Rajeev Shah has served as a member of our Board of Directors since March 2017. Mr. Shah has been a managing partner at RA Capital Management, L.P., a multi-stage investment manager dedicated to evidence-based investing in public and private healthcare and life science companies that are developing drugs, medical devices, and diagnostics, since 2004. Mr. Shah is also a member of the Board of Directors of Kala Pharmaceuticals, Inc., Satsuma Pharmaceuticals, Inc. and Black Diamond Therapeutics, Inc., each a public biopharmaceutical company. Mr. Shah was previously a member of the Board of Directors of Eidos Therapeutics, Inc., KalVista Pharmaceuticals, Inc. and Ra Pharmaceuticals, Inc., all public pharmaceutical companies. Mr. Shah received a B.A. in Chemistry from Cornell University. Mr. Shah is qualified to serve on our Board of Directors because of his extensive leadership experience, his public company board experience and his experience investing in life science companies.

Adam Stone has served as a member of our board of directors since November 2015. Mr. Stone is currently the Chief Investment Officer of Perceptive Advisors, a life sciences focused investing firm, where he has worked since 2006. Since July 2021 and February 2021, respectively, Mr. Stone has served as a director and Chief Executive Officer of ARYA Sciences Acquisition Corp V and ARYA Sciences Acquisition Corp IV. Mr. Stone received a B.A. in molecular biology from Princeton University. Mr. Stone is qualified to serve on our Board of Directors because of his extensive experience developing early-stage biotech and healthcare companies qualifies.

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Lynne Sullivan has served as a member of our Board of Directors since November 2015. Ms. Sullivan has served as the Chief Financial Officer for UNITY Biotechnology, Inc., a biotechnology company, since August 2020. Prior to that, Ms. Sullivan served as the Chief Financial Officer for Compass Therapeutics, LLC, a biotechnology company, or Compass, from December 2018 to August 2019. Prior to Compass, Ms. Sullivan served as Biogen’s senior vice president of Finance from 2016 to December 2018, where she also served as vice president of Tax and Corporate Finance from February 2015 to March 2016 and vice president of Tax from April 2008 to February 2015. Ms. Sullivan is currently a member of the Board of Directors of BiomX Inc., and Inozyme Pharma, Inc.,both of which are public biopharmaceutical companies. She received an M.S. in Taxation from Bentley University and a B.S.B.A. from Suffolk University. Ms. Sullivan was a Certified Public Accountant for over 20 years. Ms. Sullivan is qualified to serve on our Board of Directors because of her extensive experience in public accounting and financial expertise and her experience working in the healthcare sector.

Audit Committee

Our Board of Directors has established an audit committee, which operates under a charter that has been approved by our Board of Directors and that is available on the Investor Relations portion of our website, www.solidbio.com.Our audit committee consists of Ms. Sullivan, Dr.Keresty, and Dr. Koppel, with Ms. Sullivan serving as chair of the audit committee. Additionally, Mr. Arnold served as a member of the audit committee through June 16, 2021. Our Board of Directors has determined that each of these individuals meets the independence requirements of the Sarbanes-Oxley Act, Rule 10A-3 under the Exchange Act, and the applicable listing standards of Nasdaq. Each member of our audit committee can read and understand fundamental financial statements in accordance with Nasdaq audit committee requirements. In arriving at this determination, the board has examined each audit committee member’s employment and other experience. Our Board of Directors has determined that Ms. Sullivan qualifies as an audit committee financial expert within the meaning of SEC regulations and meets the financial sophistication requirements of the Nasdaq listing rules. In making this determination, our board has considered Ms. Sullivan’s formal education and previous and current experience in financial roles. Both our independent registered public accounting firm and management periodically meet privately with our audit committee.

Our audit committee’s responsibilities include, among other things:

• overseeing our risk assessment and risk management policies;

• reviewing and approving or ratifying any related person transactions;

• reviewing on a periodic basis our investment policy; and

• preparing the audit committee report required by SEC rules.

Our Board of Directors has determined that the composition and functioning of our audit committee complies with all applicable requirements of the Sarbanes-Oxley Act, and all applicable SEC and Nasdaq rules and regulations.

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Code of business conduct and ethics

We have adopted a Code of Business Conduct and Ethics, or the Code of Conduct, that applies to our directors, executive officers and employees, including our principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions. The Code of Conduct is available on the Investor Relations portion of our website, www.solidbio.com. The nominating and corporate governance committee of our Board of Directors is responsible for overseeing the Code of Conduct and must approve any waivers of the Code of Conduct for employees, executive officers and directors. In addition, we intend to post on our website all disclosures that are required by law or the listing standards of Nasdaq concerning any amendments to, or waivers of, any provision of the Code of Conduct.

Item 11. Executive Compensation.

Compensation of our Named Executive Officers

The following information describes the material elements of compensation awarded to, earned by or paid to each of our named executive officers, or the Named Executive Officers. The Named Executive Officers for the year ended December 31, 2021 are:

• Ilan Ganot, our President and Chief Executive Officer;

• Erin Powers Brennan, our Chief Legal Officer; and

• Joel Schneider. Ph.D., our Chief Operating Officer.

2021Summary Compensation Table

The following table contains information about the compensation paid to or earned by each of our Named Executive Officers for the years ended December 31, 2021 and 2020.

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Narrative to Summary Compensation Table

Base Salary. In 2021, we paid Mr. Ganot an annualized base salary of $551,100 and Dr. Schneider an annualized base salary of $423,256. In connection with the commencement of Ms. Brennan’s employment in March 2021, our Board of Directors set Ms. Brennan’s annualized base salary of $410,000. For 2022, our Board of Directors increased the base salary amount for Mr. Ganot to $578,700, for Ms. Brennan to $430,500 and for Dr. Schneider to $460,900.

We use base salaries to recognize the experience, skills, knowledge and responsibilities required of all our employees, including our Named Executive Officers. None of our Named Executive Officers is currently party to an employment agreement or other agreement or arrangement that provides for automatic or scheduled increases in base salary.

Annual Bonus. Our Board of Directors may, in its discretion, award bonuses to our Named Executive Officers from time to time. Our employment agreements with our Named Executive Officers provide that they will be eligible for annual performance-based bonuses up to a specified percentage of their salary, subject to approval by our Board of Directors. Performance-based bonuses, which are calculated as a percentage of base salary, are designed to motivate our employees to achieve annual goals based on our strategic, financial and operating performance objectives. From time to time, our Board of Directors has approved discretionary annual cash bonuses to our Named Executive Officers with respect to their prior year performance.

With respect to 2021, our Board of Directors awarded discretionary bonuses of $187,925, $145,698 and $118,320 to Mr. Ganot, Ms. Brennan and Dr. Schneider, respectively.

Our Board of Directors awarded a signing bonus of $50,000 to Ms. Brennan in connection with the commencement of her employment.

Equity Incentives. Although we do not have a formal policy with respect to the grant of equity incentive awards to our executive officers, or any formal equity ownership guidelines applicable to them, we believe that equity grants provide our executives with a strong link to our long-term performance, create an ownership culture and help to align the interests of our executives and our stockholders. In addition, we believe that equity grants with a time-based vesting feature promote executive retention because this feature incents our executive officers to remain in our employment during the vesting period. Accordingly, our Board of Directors periodically reviews the equity incentive compensation of our Named Executive Officers and from time to time may grant equity incentive awards to them in the form of stock options or restricted stock units.

In January 2021, we granted options to purchase 438,000 shares of our common stock to Mr. Ganot and 175,000 shares of our common stock to Dr. Schneider. These options vest in equal annual installments over a term of four years from the date of grant.

In March 2021, we granted options to purchase 325,000 shares of our common stock to Ms. Brennan and 15,000 shares of our common stock to Dr. Schneider. These options vest in equal annual installments over a term of four years from the date of grant.

In January 2022, we granted options to purchase 466,000 shares of our common stock and restricted stock units with respect to 233,000 shares of our common stock to Mr. Ganot, options to purchase 127,000 shares of our common stock and restricted stock units with respect to 63,000 shares of our common stock to Ms. Brennan, and options to purchase 180,000 shares of our common stock and restricted stock units with respect to 90,000 shares of our common stock to Dr. Schneider. The options and restricted stock units vest in equal annual installments over a term of four years from the date of grant.

In January 2022, we also granted restricted stock units with respect to 81,250 shares of our common stock to Ms. Brennan. The restricted stock units vest on the second anniversary of the grant date.

Our employees and executives are eligible to receive stock options and other stock-based awards pursuant to our 2020 Equity Incentive Plan, or the 2020 Plan.

We use stock options and/or restricted stock units to compensate our executive officers in the form of initial grants in connection with the commencement of employment and also at various times, often but not necessarily annually, if we have performed as expected or better than expected. None of our executive officers is currently party to an employment agreement that provides for automatic award of stock options or restricted stock units. We have granted stock options to our executive officers with time-based vesting. The options and restricted stock units that we have granted to our executive officers typically become exercisable as to 25% of the shares underlying the option on the first anniversary of the grant date and as to

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an additional 25% of the original number of shares underlying the option annually thereafter. Vesting rights cease upon termination of employment and exercise rights cease shortly after termination, except that vesting is fully accelerated upon certain terminations in connection with a change of control and exercisability is extended in the case of death or disability. Prior to the exercise of an option or the vesting of a restricted stock unit, the holder has no rights as a stockholder with respect to the shares subject to such option or with respect to the restricted stock units, including no voting rights and no right to receive dividends or dividend equivalents.

The exercise price of all stock options granted after the closing of our initial public offering is equal to the fair market value of shares of our common stock on the date of grant, which is determined by reference to the closing market price of our common stock on the date of grant.

Employment Agreements

We have entered into employment agreements with each of our Named Executive Officers. The employment agreements set forth the terms of the Named Executive Officers’ compensation, including their base salary, and annual performance bonus opportunity. In addition, the employment agreements provide that, subject to eligibility requirements under the plan documents governing such programs and our policies, the Named Executive Officers are entitled, on the same basis as our other employees, to participate in and receive benefits under, any medical, vision and dental insurance policy maintained by us and we will pay, consistent with our then-current employee benefit policy, a portion of the cost of the premiums for any such insurance policy in which the Named Executive Officer elects to participate. Each Named Executive Officer will also be eligible to receive paid vacation time, sick time, and Company holidays consistent with our policies as then in effect from time to time and equity awards at such times and on such terms and conditions as the Board of Directors may determine. Each Named Executive Officer’s employment is at will.

Employment Agreement with Ilan Ganot

On January 25, 2019, we entered into an employment agreement with Mr. Ganot, our President and Chief Executive Officer, which employment agreement amended and restated the terms of his existing agreement (with the exception of the restrictive covenant provisions contained therein).

Pursuant to his employment agreement, Mr. Ganot is being paid a salary of $578,700 for 2022, which base salary will be reviewed by the Board of Directors from time to time and is subject to change in the discretion of the Board of Directors. Mr. Ganot is also eligible to earn an annual performance bonus, with a target bonus amount equal to up to 55% of his base salary, based upon the board’s assessment of his performance and the Company’s attainment of targeted goals as set by the board in its sole discretion. The bonus may be in the form of cash, equity award(s), or a combination of cash and equity.

Mr. Ganot is bound by proprietary rights, non-disclosure, developments, non-competition and non-solicitation obligations pursuant to the restrictive covenants in his existing employment agreement, which provisions remain in full force and effect. Under these restrictive covenants, he has agreed not to compete with us during his employment and for a period of one year after the termination of his employment (provided that he is not restricted from promoting treatments for, or endeavoring to cure, Duchenne), not to solicit our employees, consultants, or actual or prospective customers or business relations during his employment and for a period of one year after the termination of his employment, and to protect our confidential and proprietary information indefinitely.

Mr. Ganot’s employment agreement and his employment may be terminated: (1) upon his death or at our election due to his “disability”; (2) at our election, with or without “cause”; and (3) at his election, with or without “good reason” (as such terms are defined in his employment agreement).

In the event of the termination of Mr. Ganot’s employment by us without cause, or by Mr. Ganot for good reason, prior to or more than twelve months following a “change in control” (as defined in his employment agreement), Mr. Ganot is entitled to receive his base salary that has accrued and to which he is entitled as of the termination date, to the extent consistent with Company policy, accrued but unused paid time off through and including the termination date, unreimbursed business expenses for which expenses he has timely submitted appropriate documentation, and other amounts or benefits to which he is entitled in accordance with the terms of the benefit plans then-sponsored by us, which we refer to collectively as the Ganot Accrued Obligations. In addition, subject to his execution and nonrevocation of a release of claims in our favor, Mr. Ganot is entitled to (1) continued payment of his base salary, in accordance with our regular payroll procedures, for a period of 12 months and (2) provided he is eligible for and timely elects to continue receiving group medical insurance under COBRA and the payments would not result in the violation of nondiscrimination requirements of applicable law, payment by

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us of the portion of health coverage premiums we pay for similarly-situated, active employees who receive the same type of coverage, for a period of up to 12 months following his date of termination.

In the event of the termination of Mr. Ganot’s employment by us without cause, or by Mr. Ganot for good reason, within twelve months following a change in control, he is entitled to receive the Ganot Accrued Obligations. In addition, subject to his execution and nonrevocation of a release of claims in our favor, he is entitled to (1) continued payment of his base salary, in accordance with our regular payroll procedures, for a period of 18 months, (2) provided he is eligible for and timely elects to continue receiving group medical insurance under COBRA and the payments would not result in the violation of nondiscrimination requirements of applicable law, payment by us of the portion of health coverage premiums we pay for similarly-situated, active employees who receive the same type of coverage, for a period of up to 18 months following his date of termination, (3) a lump sum payment equal to 150% of his target bonus for the year in which his employment is terminated or, if higher, his target bonus immediately prior to the change in control and (4) full vesting acceleration of any then-unvested equity awards that vest based solely based on the passage of time held by Mr. Ganot, such that any such equity awards held by him become fully exercisable or non-forfeitable as of the termination date.

If Mr. Ganot’s employment is terminated for any other reason, including as a result of his death or disability, for cause, or voluntarily by him without good reason, our obligations under the employment agreement cease immediately, and he is only entitled to receive the Ganot Accrued Obligations.

Employment Agreement with Erin Powers Brennan

On March 1, 2021, we entered into an employment agreement with Ms. Brennan, our Chief Legal Officer.

Pursuant to her employment agreement, Ms. Brennan is being paid an annual base salary of $430,500 for 2022, which base salary will be reviewed by the Board of Directors from time to time and is subject to change in the discretion of the Board of Directors. Ms. Brennan is also eligible to earn an annual performance bonus, with a target bonus amount equal to up to 40% of her base salary, based upon the board’s assessment of her performance and the Company’s attainment of targeted goals as set by the board in its sole discretion. The bonus may be in the form of cash, equity award(s), or a combination of cash and equity.

Ms. Brennan is bound by proprietary rights, non-disclosure, developments, non-competition and non-solicitation obligations pursuant to the employment agreement. Under these restrictive covenants, she has agreed not to compete with us during her employment and for a period of one year after the termination of her employment, not to solicit our employees, consultants, or actual or prospective customers or business relations during her employment and for a period of one year after the termination of her employment, and to protect our confidential and proprietary information indefinitely.

Ms. Brennan’s employment agreement and her employment may be terminated: (1) upon her death or at our election due to her “disability”; (2) at our election, with or without “cause”; and (3) at her election, with or without “good reason” (as such terms are defined in her employment agreement).

In the event of the termination of Ms. Brennan’s employment by us without cause, or by Ms. Brennan for good reason, prior to or more than twelve months following a “change in control” (as defined in her employment agreement), Ms. Brennan is entitled to receive her base salary that has accrued and to which she is entitled as of the termination date, to the extent consistent with Company policy, accrued but unused paid time off through and including the termination date, unreimbursed business expenses for which expenses she has timely submitted appropriate documentation, and other amounts or benefits to which she is entitled in accordance with the terms of the benefit plans then-sponsored by us, which we refer to collectively as the Brennan Accrued Obligations. In addition, subject to her execution and nonrevocation of a release of claims in our favor, Ms. Brennan is entitled to (1) continued payment of her base salary, in accordance with our regular payroll procedures, for a period of 12 months and (2) provided she is eligible for and timely elects to continue receiving group medical insurance under COBRA and the payments would not result in the violation of nondiscrimination requirements of applicable law, payment by us of the portion of health coverage premiums we pay for similarly-situated, active employees who receive the same type of coverage, for a period of up to 12 months following her date of termination.

In the event of the termination of Ms. Brennan’s employment by us without cause, or by Ms. Brennan for good reason, within twelve months following a change in control, she is entitled to receive the Brennan Accrued Obligations. In addition, subject to her execution and nonrevocation of a release of claims in our favor, she is entitled to (1) continued payment of her base salary, in accordance with our regular payroll procedures, for a period of 12 months, (2) provided she is eligible for and timely elects to continue receiving group medical insurance under COBRA and the payments would not result in the violation of nondiscrimination requirements of applicable law, payment by us of the portion of health coverage premiums we pay for similarly-situated, active employees who receive the same type of coverage, for a period of up to 12 months following her

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date of termination, (3) a lump sum payment equal to 100% of her target bonus for the year in which her employment is terminated or, if higher, her target bonus immediately prior to the change in control and (4) full vesting acceleration of any then-unvested equity awards that vest based solely based on the passage of time held by Ms. Brennan, such that any such equity awards held by her become fully exercisable or non-forfeitable as of the termination date.

If Ms. Brennan’s employment is terminated for any other reason, including as a result of her death or disability, for cause, or voluntarily by her without good reason, our obligations under the employment agreement cease immediately, and she is only entitled to receive the Brennan Accrued Obligations

Employment Agreement with Joel Schneider

On January 25, 2019, we entered into an employment agreement with Dr. Schneider, our Chief Operating Officer, which employment agreement amended and restated the terms of his existing agreement (with the exception of the restrictive covenant provisions contained therein).

Pursuant to his employment agreement, Dr. Schneider is being paid an annual base salary of $460,900 for 2022, which base salary will be reviewed by the Board of Directors from time to time and is subject to change in the discretion of the Board of Directors. Dr. Schneider is also eligible to earn an annual performance bonus, with a target bonus amount equal to up to 40% of his base salary, based upon the board’s assessment of his performance and the Company’s attainment of targeted goals as set by the board in its sole discretion. The bonus may be in the form of cash, equity award(s), or a combination of cash and equity.

Dr. Schneider is bound by proprietary rights, non-disclosure, developments, non-competition and non-solicitation obligations pursuant to the restrictive covenants in his existing employment agreement, which provisions remain in full force and effect. Under these restrictive covenants, he has agreed not to compete with us during his employment and for a period of one year after the termination of his employment, not to solicit our employees, consultants, or actual or prospective customers or business relations during his employment and for a period of one year after the termination of his employment, and to protect our confidential and proprietary information indefinitely.

Dr. Schneider’s employment agreement and his employment may be terminated: (1) upon his death or at our election due to his “disability”; (2) at our election, with or without “cause”; and (3) at his election, with or without “good reason” (as such terms are defined in his employment agreement).

In the event of the termination of Dr. Schneider’s employment by us without cause, or by Dr. Schneider for good reason, prior to or more than twelve months following a “change in control” (as defined in his employment agreement), Dr. Morris is entitled to receive his base salary that has accrued and to which he is entitled as of the termination date, to the extent consistent with Company policy, accrued but unused paid time off through and including the termination date, unreimbursed business expenses for which expenses he has timely submitted appropriate documentation, and other amounts or benefits to which he is entitled in accordance with the terms of the benefit plans then-sponsored by us, which we refer to collectively as the Schneider Accrued Obligations. In addition, subject to his execution and nonrevocation of a release of claims in our favor, Dr. Schneider is entitled to (1) continued payment of his base salary, in accordance with our regular payroll procedures, for a period of 12 months and (2) provided he is eligible for and timely elects to continue receiving group medical insurance under COBRA and the payments would not result in the violation of nondiscrimination requirements of applicable law, payment by us of the portion of health coverage premiums we pay for similarly-situated, active employees who receive the same type of coverage, for a period of up to 12 months following his date of termination.

In the event of the termination of Dr. Schneider’s employment by us without cause, or by Dr. Schneider for good reason, within twelve months following a change in control, he is entitled to receive the Morris Accrued Obligations. In addition, subject to his execution and nonrevocation of a release of claims in our favor, he is entitled to (1) continued payment of his base salary, in accordance with our regular payroll procedures, for a period of 12 months, (2) provided he is eligible for and timely elects to continue receiving group medical insurance under COBRA and the payments would not result in the violation of nondiscrimination requirements of applicable law, payment by us of the portion of health coverage premiums we pay for similarly-situated, active employees who receive the same type of coverage, for a period of up to 12 months following his date of termination, (3) a lump sum payment equal to 100% of his target bonus for the year in which his employment is terminated or, if higher, his target bonus immediately prior to the change in control and (4) full vesting acceleration of any then-unvested equity awards that vest based solely based on the passage of time held by Dr. Schneider, such that any such equity awards held by him become fully exercisable or non-forfeitable as of the termination date.

If Dr. Schneider’s employment is terminated for any other reason, including as a result of his death or disability, for cause, or voluntarily by him without good reason, our obligations under the employment agreement cease immediately, and he is only entitled to receive the Schneider Accrued Obligations.

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2021 Outstanding Equity Awards at Fiscal Year-End

The following table sets forth information regarding equity awards held by our Named Executive Officers as of December 31, 2021.

Option Awards Stock Awards

On January 27, 2022, we granted a stock option to Mr. Ganot, Ms. Brennan and Dr. Schneider for the right to buy 466,000, 127,000 and 180,000 shares of our common stock, respectively. The options have an exercise price of $1.13 per share, vest in four equal annual installments beginning on January 27, 2023 and expire on January 27, 2032. On January 27, 2022, we granted RSUs to Mr. Ganot, Ms. Brennan and Dr. Schneider for the right to common shares of 233,000, 63,000 and 90,000 shares of our common stock, respectively. These RSUs vest in four equal annual installments beginning on January 27, 2023.

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On January 27, 2022, we also granted RSUs to Ms. Brennan for the right to common shares of 81,250 of our common stock. These RSUs vest on the second anniversary of the grant date.

Equity Incentive Plans

Solid Biosciences, LLC Amended and Restated Equity Incentive Plan

Prior to the closing of our initial public offering, Solid Biosciences, LLC maintained its Amended and Restated Equity Incentive Plan, or the Existing Plan, under which Solid Biosciences, LLC granted Series D Common Units to its employees, consultants and other service providers. The Existing Plan was frozen in connection with our initial public offering. No further awards will be granted under the Existing Plan, but awards granted prior to the freeze date will continue in accordance with their terms and the terms of the Existing Plan.

2018 Omnibus Incentive Plan

Prior to our initial public offering, the board of managers of Solid Biosciences, LLC adopted the Solid Biosciences Inc. 2018 Omnibus Incentive Plan, or 2018 Plan, contingent upon the consummation of our initial public offering. The unitholders of Solid Biosciences, LLC approved the 2018 Plan contingent upon the consummation of our initial public offering.

As of the effective date of the 2020 Plan, no further awards will be made under the 2018 Plan. Any options or awards outstanding under the 2018 Plan remain outstanding and effective and are governed by their existing terms.

The material terms of the 2018 Plan are summarized below. The following summary is qualified in its entirety by reference to the complete text of the 2018 Plan, a copy of which was filed as Exhibit 99.1 to our registration statement on Form S-8 filed with the SEC on January 29, 2018 and is incorporated herein by reference.

Administration of the plan

The board of managers of Solid Biosciences, LLC appointed the compensation committee of our Board of Directors as the committee under the 2018 Plan with the authority to administer the 2018 Plan. We refer to our Board of Directors or compensation committee, as applicable, as the Administrator. The Administrator is authorized to grant awards to eligible employees, consultants and non-employee directors.

Types of awards

Stock options. The 2018 Plan authorized the Administrator to grant incentive stock options, or ISOs, to eligible employees and non-qualified stock options to purchase shares to employees, consultants, prospective employees, prospective consultants and non-employee directors. The Administrator determined the number of shares of common stock subject to each option, the term of each option, the exercise price (which may not be less than the fair market value of the shares of common stock at the time of grant, or 110% of fair market value in the case of ISOs granted to 10% stockholders), the vesting schedule and the other terms and conditions of each option. Options are exercisable at such times and subject to such terms as were determined by the Administrator at the time of grant. The maximum term of options under the 2018 Plan is ten years (or five years in the case of ISOs granted to 10% stockholders). Upon the exercise of an option, the participant must make payment of the full exercise price (a) in cash or by check, bank draft or money order; (b) solely to the extent permitted by law and authorized by the Administrator, through the delivery of irrevocable instructions to a broker, reasonably acceptable to us, to promptly deliver to us an amount equal to the aggregate exercise price; or (c) on such other terms and conditions as may be acceptable to the Administrator (including, without limitation, the relinquishment of options or by payment in full or in part in the form of shares of common stock).

Restricted stock. The 2018 Plan authorized the Administrator to grant restricted stock. Any recipients of restricted stock were required to enter into an agreement with us subjecting the restricted stock to transfer and other restrictions and providing the criteria or dates on which such awards vest and such restrictions lapse. The restrictions on restricted stock may lapse and the awards may vest over time, based on performance criteria or other factors, as determined by the Administrator at the time of grant. Except as otherwise determined by the Administrator, a holder of restricted stock has all of the attendant rights of a stockholder including the right to receive dividends, if any, subject to and conditioned upon vesting and restrictions lapsing on the underlying restricted stock, the right to vote shares and, subject to and conditioned upon the vesting and restrictions lapsing for the underlying shares, the right to tender such shares. However, the Administrator may in its discretion provide at the time of grant that the right to receive dividends on restricted stock will not be subject to the vesting or lapsing of the restrictions on the restricted stock.

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Other stock-based awards. The 2018 Plan authorized the Administrator to grant awards of shares of common stock and other awards that are valued in whole or in part by reference to, or are payable in or otherwise based on, shares of common stock, including, but not limited to, shares of common stock awarded purely as a bonus and not subject to any restrictions or conditions; shares of common stock in payment of the amounts due under an incentive or performance plan sponsored or maintained by us or an affiliate; stock appreciation rights; stock equivalent units; restricted stock units; performance awards entitling participants to receive a number of shares of common stock (or cash in an equivalent value) or a fixed dollar amount, payable in cash, stock or a combination of both, with respect to a designated performance period; or awards valued by reference to book value of our shares of common stock. In general, other stock-based awards that are denominated in shares of common stock include the right to receive dividends, if any, subject to and conditioned upon vesting and restrictions lapsing on the underlying award, but the Administrator may in its discretion provide at the time of grant that the right to receive dividends on a stock-denominated award will not be subject to the vesting or lapsing of the restrictions on the performance award.

Performance-based cash awards. The 2018 Plan authorized the Administrator to grant cash awards that are payable or otherwise based on the attainment of pre-established performance goals during a performance period. Any such performance goals are based on the attainment of a certain target level of, or a specified increase in (or decrease where noted), criteria selected by the Administrator.

Effect of certain transactions; Change in control

In the event of a change in control, as defined in the 2018 Plan, except as otherwise provided by the Administrator, unvested awards will not vest. Instead, the Administrator may, in its sole discretion, provide that outstanding awards will be: assumed and continued; purchased based on the price per share paid in the change in control transaction (less, in the case of options and stock appreciation rights, or SARs, the exercise price), as adjusted by the Administrator for any contingent purchase price, escrow obligations, indemnification obligations or other adjustments to the purchase price; and/or in the case of stock options or other stock-based appreciation awards where the change in control price is less than the applicable exercise price, cancelled. However, the Administrator may in its sole discretion provide for the acceleration of vesting and lapse of restrictions of an award at any time including in connection with a change in control.

Non-transferability of awards

Except as the Administrator may permit, at the time of grant or thereafter, awards granted under the 2018 Plan are generally not transferable by a participant other than by will or the laws of descent and distribution. Shares of common stock acquired by a permissible transferee will continue to be subject to the terms of the 2018 Plan and the applicable award agreement.

Amendment and termination

Subject to the rules referred to in the balance of this paragraph, our Board of Directors or the Administrator (to the extent permitted by law) may at any time amend, in whole or in part, any or all of the provisions of the 2018 Plan, or suspend or terminate it entirely, retroactively or otherwise. Except as required to comply with applicable law, no such amendment, suspension or termination may reduce the rights of a participant with respect to awards previously granted without the consent of such participant. In addition, without the approval of stockholders, no amendment may be made that would: increase the aggregate number of shares of common stock that may be issued under the 2018 Plan; increase the maximum individual participant share limitations for a fiscal year or year of a performance period; change the classification of individuals eligible to receive awards under the 2018 Plan; extend the maximum term of any option; reduce the exercise price of any option or SAR or cancel any outstanding “in-the-money” option or SAR in exchange for cash; substitute any option or SAR in exchange for an option or SAR (or similar other award) with a lower exercise price; alter the performance goals; or require stockholder approval in order for the 2018 Plan to continue to comply with Section 162(m) or Section 422 of the Internal Revenue Code of 1986, as amended, or the Code.

Registration of shares

On January 29, 2018, we filed a registration statement on Form S-8 under the Securities Act of 1933, as amended, or the Securities Act, to register the full number of shares of common stock available for issuance under the 2018 Plan.

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2020 Equity Incentive Plan

Our 2020 Equity Incentive Plan, or the 2020 Plan, which became effective on June 16, 2020, was adopted by our Board of Directors in April 2020 and approved by our stockholders approved in June 2020.

The material terms of the 2020 Plan are summarized below. The following summary is qualified in its entirety by reference to the complete text of the 2020 Plan, a copy of which is filed as Exhibit 10.26 to this Annual Report on Form 10-K and is incorporated herein by reference.

Types of Awards; Shares Available for Awards

The 2020 Plan provides for the grant of incentive stock options intended to qualify under Section 422 of the Code, nonstatutory stock options, SARs, restricted stock, restricted stock units, other stock-based awards and cash awards as described below, which we collectively refer to as awards.

Subject to adjustment in the event of stock splits, stock dividends or similar events, awards may be made under the 2020 Plan for up to the sum of 3,000,000 shares of our common stock plus such additional number of shares of our common stock (up to 4,879,025 shares) as is equal to (x) the number of shares of our common stock reserved for issuance under the 2018 Plan that remained available for grant under the 2018 Plan immediately prior to the date that the 2020 Plan was approved by our stockholders and (y) the number of shares of common stock subject to awards granted under the 2018 Plan, which awards expire, terminate or are otherwise surrendered, cancelled or forfeited or repurchased by us pursuant to a contractual repurchase right. On June 16, 2021, our stockholders approved an amendment to the 2020 Plan to reserve an additional 7,000,000 shares of common stock for issuance under the 2020 Plan. At December 31, 2021, 8,557,152 shares remained available for future issuance under the 2020 Plan.

The 2020 Plan provides that the maximum amount of cash and equity compensation (calculated based on grant date fair value for financial reporting purposes) granted to any individual non-employee director in his or her capacity as a non-employee director in any calendar year may not exceed $500,000 in the case of an incumbent non-employee director or $1,000,000 in the case of the first year of service of a non-employee director. Exceptions to this limitation may only be made by our board, in its discretion, in extraordinary circumstances, provided that the non-employee director receiving the additional compensation does not participate in the decision to award such compensation. Cash and awards granted under the 2020 Plan to non-employee directors in their capacity as our consultants or advisors are not subject to this limitation.

Descriptions of Awards

Options. Optionees receive the right to purchase a specified number of shares of common stock at a specified exercise price and subject to the other terms and conditions that are specified in connection with the option grant. An option that is not intended to be an “incentive stock option” is a “nonstatutory stock option”. Options may not be granted at an exercise price that is less than 100% of the fair market value of our common stock on the date of grant. Under the terms of the 2020 Plan, options may not be granted for a term in excess of ten years. The 2020 Plan permits participants to pay the exercise price of options using one or more of the following manners of payment: (i) payment by cash, by check, (ii) except as may otherwise be provided in the applicable option agreement or approved by our board, in connection with a “cashless exercise” through a broker, (iii) to the extent provided in the applicable option agreement or approved by our board, and subject to certain conditions, by delivery of shares of common stock to us owned by the participant valued at their fair market value, (iv) to the extent provided in an applicable nonstatutory stock option agreement or approved by our board, by delivery of a notice of “net exercise” as a result of which we will retain a number of shares of common stock otherwise issuable pursuant to the stock option equal to the aggregate exercise price for the portion of the option being exercised divided by the fair market value of our common stock on the date of exercise, (v) to the extent permitted by applicable law and provided for in the applicable option agreement or approved by our board, by any other lawful means (but not by a promissory note of the participant), or (vi) by any combination of these forms of payment.

Stock Appreciation Rights. An SAR is an award entitling the holder, upon exercise, to receive a number of shares of our common stock, or cash (or a combination of shares of our common stock and cash) determined by reference to appreciation, from and after the date of grant, in the fair market value of a share of our common stock over the measurement price. The 2020 Plan provides that the measurement price of an SAR may not be less than the fair market value of our common stock on the date the SAR is granted and that SARs may not be granted with a term in excess of 10 years.

Restricted Stock Awards. Restricted stock awards entitle recipients to acquire shares of our common stock, subject to our right to repurchase all or part of such shares at their issue price or other stated or formula price (or to require forfeiture of

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such shares if issued at no cost) in the event that the conditions specified in the applicable award are not satisfied prior to the end of the applicable restriction period established for such award.

Restricted Stock Unit Awards. Restricted stock units, or RSUs, entitle the recipient to receive shares of our common stock, or cash equal to the fair market value of such shares, to be delivered at the time such award vests pursuant to the terms and conditions established by our board.

Other Stock-Based Awards. Under the 2020 Plan, our board may grant other awards of shares of our common stock, and other awards that are valued in whole or in part by reference to, or are otherwise based on, shares of our common stock or other property, having such terms and conditions as our board may determine. We refer to these types of awards as other stock-based awards. Other stock-based awards may be available as a form of payment in settlement of other awards granted under the 2020 Plan or as payment in lieu of compensation to which a participant is otherwise entitled. Other stock-based awards may be paid in shares of our common stock or in cash, as our board may determine.

Cash Awards. Under the 2020 Plan, the board has the right to grant cash-based awards including awards subject to performance conditions.

Performance Conditions. Our board may specify that the degree of granting, vesting and/or payout of any award is subject to the achievement of one or more of performance measures enumerated in the 2020 Plan and established by the board.

Eligibility to Receive Awards

All of our employees, officers, and directors, as well as our consultants and advisors, are eligible to receive awards under the 2020 Plan. However, incentive stock options may only be granted to our employees.

Transferability of Awards

Except as our board may permit, awards may not be sold, assigned, transferred, pledged or otherwise encumbered by a participant, either voluntarily or by operation of law, except by will or the laws of descent and distribution or, other than in the case of an incentive stock option, pursuant to a qualified domestic relations order.

Administration

The 2020 Plan is administered by our board. Pursuant to the terms of the 2020 Plan, our board may delegate any or all of its powers under the 2020 Plan to one or more committees or subcommittees of our board. The board has authorized our compensation committee to administer certain aspects of the 2020 Plan, including the granting of awards to executive officers. The Board of Directors, or any such committee, may delegate to one of our officers, the authority to make grants under the 2020 Plan, subject to the limitations set forth in the 2020 Plan.

Subject to any applicable limitations contained in the 2020 Plan, the board, our compensation committee, or any other committee or officer to whom the board delegates authority, as the case may be, selects the recipients of awards and determines (i) the number of shares of common stock, cash or other consideration covered by awards and the terms and conditions of such awards, including the dates upon which such awards become exercisable or otherwise vest, (ii) the exercise or measurement price of awards, if any, and (iii) the duration of awards.

In the event of any stock split, reverse stock split, stock dividend, recapitalization, combination of shares, reclassification of shares, spin-off or other similar change in capitalization or event, or any dividend or distribution to holders of our common stock, other than an ordinary cash dividend, we are required to make equitable adjustments (or make substituted awards, as applicable), in the manner determined by our board, to (i) the number and class of securities available under the 2020 Plan, (ii) the share counting rules and sublimit set forth in the 2020 Plan, (iii) the number and class of securities and exercise price per share of each outstanding option, (iv) the share- and per-share provisions and the measurement price of each outstanding SAR, (v) the number of shares subject to and the repurchase price per share subject to each outstanding award of restricted stock, and (vi) the share and per-share-related provisions and the purchase price, if any, of each outstanding RSU award and each outstanding other stock-based award.

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Amendment of Awards

Except as otherwise provided under the 2020 Plan with respect to repricing outstanding stock options or SARs, our board may amend, modify or terminate any outstanding award, including but not limited to, substituting therefor another award of the same or a different type, changing the date of exercise or realization, and converting an incentive stock option to a nonstatutory stock option, provided that the participant’s consent to any such action will be required unless our board determines that the action, taking into account any related action, does not materially and adversely affect the participant’s rights under the 2020 Plan or the change is otherwise permitted under the terms of the 2020 Plan in connection with a change in capitalization or reorganization event.

Reorganization Events

The 2020 Plan contains provisions addressing the consequences of any reorganization event. A reorganization event is defined under the 2020 Plan as (a) any merger or consolidation of us with or into another entity as a result of which all of our common stock is converted into or exchanged for the right to receive cash, securities or other property, or is cancelled, (b) any transfer or disposition of all of our common stock for cash, securities or other property pursuant to a share exchange or other transaction or (c) our liquidation or dissolution.

Amendment or Termination

No award may be granted under the 2020 Plan after June 15, 2030, but awards previously granted may extend beyond that date. Our board may amend, suspend or terminate the 2020 Plan or any portion of the 2020 Plan at any time, except that no amendment that would amend the prohibitions on repricing without stockholder approval may be amended without stockholder approval and no amendment that would require stockholder approval under the rules of the national securities exchange on which we then maintains our primary listing may be made effective unless and until such amendment has been approved by our stockholders.

Registration of Shares

On August 6, 2020 and August 16, 2021, we filed a registration statement on Form S-8 under the Securities Act to register the full number of shares of common stock available for issuance under the 2020 Plan.

2021 Employee Stock Purchase Plan

Our ESPP was adopted by our Board of Directors in April 2021 and approved by our stockholders in June 2021. The ESPP is administered by our Board of Directors or by a committee appointed by our Board of Directors. The ESPP provides for 1,102,885 shares to be available for purchase by eligible employees according to its terms.

All of our employees, including directors who are employees, and all employees of any of our subsidiaries designated by our board from time to time, are eligible to participate in the ESPP provided that:

We retain the discretion to determine which eligible employees may participate in an offering under applicable regulations.

Offerings under the ESPP will begin on dates determined by our board and will continue for six months, which we refer to as the plan purchase period. Payroll deductions made during each plan purchase period will be held for the purchase of our common stock at the end of each plan purchase period. Our board may, in its discretion, change the date on which plan purchase periods may commence and may choose a different plan purchase period of 12 months or less for each offering.

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With respect to any offering under the ESPP, an employee may authorize a payroll deduction in any dollar amount up to a maximum of 15% of the compensation such employee receives during the plan purchase period(or during such shorter period during which payroll deductions are made). Compensation is defined under the ESPP to mean the amount of money reportable on the employee’s federal income tax withholding statement, excluding overtime, shift premium, incentive or bonus awards, allowances and reimbursements for expenses such as relocation allowances for travel expenses, income or gains associated with the grant or vesting of restricted stock, income or gains on the exercise of stock options or stock appreciation rights, and similar items, but including, in the case of salespersons, sales commissions to the extent determined by our board. Our board may, in its discretion, designate a lower maximum contribution rate, and a minimum payroll deduction may be established from time to time by our board.

On the offering commencement date of each plan purchase period, we will grant to each eligible employee who is then a participant in the ESPP a right to purchase up to a whole number of shares of our common stock determined by dividing (a) $25,000 divided by the number of full months in the plan purchase period by (b) the closing price of a share of our common stock on the offering commencement date (as determined under the ESPP); provided, however, that in the event the length of the plan purchase period exceeds twelve (12) months, the number of shares each participant may purchase pursuant to the Purchase Right shall be up to that whole number of shares of Common Stock determined by multiplying $2,083 by the number of full months on the plan purchase period and dividing the result by the closing price of a share of our common stock on the offering commencement date (as determined under the ESPP). Each employee who continues to be a participant in the ESPP on the last business day of the plan purchase period (referred to as the exercise date) is deemed to have exercised the right to purchase at the purchase right price on such date and will be deemed to have purchased from us the number of whole shares of our common stock reserved for purposes of the ESPP that such employee’s accumulated payroll deductions on the exercise date will pay for, up to the maximum number determined as set forth above.

Under the terms of the ESPP, the purchase right price shall be determined by our board for each plan purchase period and the purchase right price will be at least 85% of the applicable closing price of our common stock (determined as provided under the ESPP). If our board does not make a determination of the purchase right price, the purchase right price will be 85% of the lesser of the closing price of our common stock (determined as provided under the ESPP) on either (a) the first business day of the plan purchase period or (b) the purchase exercise date.

Any balance remaining in an employee’s payroll deduction account at the end of a plan purchase period will be automatically refunded to the employee, except that any balance which is less than the purchase price of one share of our common stock will be carried forward for the following offering, unless the employee elects not to participate in the following offering, in which case the balance in the employee’s account will be refunded. An employee may withdraw the balance accumulated in such employee’s account and withdraw from participation in an offering at any time prior to the close of business on the last business day in the plan purchase period. Any employee who so withdraws may not begin participating again during the remainder of the plan purchase period but may participate in any subsequent offering in accordance with the terms and conditions established by our board.

For purposes of monitoring the compliance with required holding periods under the ESPP, we may require that the shares purchased under the ESPP be deposited directly into a brokerage account that we establish for each participant at a brokerage firm that we designate, which we refer to as the ESPP broker account. Except as otherwise provided in the ESPP, the deposited shares may not be transferred (either electronically or in certificate form) from the ESPP broker account until the later of the following two periods: (i) the end of the two (2)-year period measured from the date the participant first commences participation in offerings under the ESPP and (ii) the end of the one (1)-year measured from the purchase exercise date of the applicable shares. Such limitation shall apply both to transfers to different accounts with the same ESPP broker and to transfers to other brokerage firms. Any shares held for the required holding period may thereafter be transferred (either electronically or in certificate form) to other accounts or to other brokerage firms.

If any employee’s employment is terminated prior to the last business day of a plan purchase period, the employee’s account balance will be refunded to the employee (without any reductions for payroll deductions) or, in the event of the employee’s death, to a designated beneficiary, to the executor or administrator of the employee’s estate, or if no executor or administrator has been appointed to our knowledge, to any other person we designate in our discretion. If, prior to the last business day of a plan purchase period, the designated subsidiary in which an employee is employed ceases to be a subsidiary of ours, or if the employee is transferred to a subsidiary that is not a designated subsidiary, the employee will be deemed to have terminated employment for purposes of the ESPP.

Rights under the ESPP are not transferable by a participating employee other than by will or the laws of descent and distribution, and are exercisable during the employee’s lifetime only by the employee.

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Shares may be issued upon exercise of an option from authorized but unissued shares of our common stock, from shares held in our treasury, or from any other proper source. In the event the total number of shares of our common stock specified in elections to be purchased under any offering plus the number of shares purchased under previous offerings under the ESPP exceeds the maximum number of shares issuable under the ESPP, our board will allot the shares then available on a pro-rata basis.

We will be required to make equitable adjustments in the manner determined by our board to the number and class of securities available under the ESPP and the purchase right price to reflect stock splits, reverse stock splits, stock dividends, recapitalizations, combinations of shares, reclassifications of shares, spin-offs and other similar changes in capitalization or any distribution to holders of our common stock other than an ordinary cash dividend.

Upon the occurrence of a Reorganization Event (as defined below), our board is authorized to take any one or more of the following actions as to outstanding purchase rights under the ESPP:

• any combination of the foregoing.

A “Reorganization Event” is defined under the ESPP as (i) any merger or consolidation of us with or into another entity as a result of which all of our common stock is converted into or exchanged for the right to receive cash, securities or other property or is cancelled, (ii) any transfer or disposition of all of the common stock of the Company for cash, securities or other property pursuant to a share exchange or other transaction, or (iii) our liquidation or dissolution.

Our board may at any time, and from time to time, amend the ESPP. We are required under the ESPP to obtain stockholder approval for any amendment if such approval is required by Section 423 of the Code. Further, our board may not make any amendment that would cause the ESPP to fail to comply with Section 423 of the Code. Our board may terminate the ESPP at any time. Upon termination, we will refund all amounts in the accounts of participating employees.

On August 16, 2021, we filed a registration statement on Form S-8 under the Securities Act to register the full number of shares of common stock available for issuance under the ESPP.

Non-employee director compensation

During 2021, we did not provide any compensation to Mr. Ganot, our President and Chief Executive Officer, for his service as a member of our board. Mr. Ganot’s compensation as an executive officer is set forth above under“Executive Compensation—2021 Summary Compensation Table.”

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Non-employee director compensation is set by our Board of Directors at the recommendation of our compensation committee. In 2021, the compensation committee retained Radford, an AON Hewitt company, to assist in assessing our non-employee director compensation program and provide recommendations with respect to the compensation program.

Under our current director compensation program, we pay our non-employee directors a cash retainer for their service on the Board of Directors and for their service on each committee of which the director is a member. The chairs of each committee receive higher retainers for such service. These fees are payable in arrears in equal semi-annual installments not later than the 15th business day following the end of the second and fourth calendar quarters, provided that the amount of such payment will be prorated for any portion of such semi-annual period that the director is not serving on the board, on such committee or in such position, and no fee shall be payable in respect of any period prior to the completion of our initial public offering. The fees paid to non-employee directors for their service on the Board of Directors and for their service on each committee of the Board of Directors of which the director is a member are as follows:

Member Annual Fee Chairperson Incremental Annual Fee

Nominating and Corporate Governance Committee 4,000 4,000

We also reimburse our non-employee directors for reasonable out-of-pocket business expenses incurred in connection with the performance of their duties as directors, including travel expenses in connection with their attendance in person at our board of director and committee meetings.

In addition, under our current director compensation program, each new non-employee director elected to our Board of Directors receives an option to purchase 40,000 shares of our common stock under our 2020 Plan. Each of these options vest in equal annual installments over a three-year period measured from the date of grant, subject to the director’s continued service as a director. Further, on the date of our annual meeting of stockholders, each non-employee director that has served on our Board of Directors for at least six months prior to such annual meeting receives an option to purchase 10,000 shares of our common stock under our 2020 Plan. Each of these options vest in full on the earlier to occur of the one-year anniversary of the grant date and immediately prior to our first annual meeting of stockholders occurring after the grant date, subject to the director’s continued service as a director. All options granted to our non-employee directors under our director compensation program will be issued at exercise prices equal to the fair market value of our common stock on the date of grant and will become exercisable in full in the event of a change in control.

This program is intended to provide compensation for our non-employee directors in a manner that enables us to attract and retain outstanding director candidates and reflects the substantial time commitment necessary to oversee our affairs. We also seek to align the interests of our directors and our stockholders, and we have chosen to do so by compensating our non-employee directors with a mix of cash and equity-based compensation.

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The table below shows the compensation paid to our non-employee directors during 2021.

Name Fees Earned or Paid in Cash ($) Option Awards ($) (1)(2) Total ($)

(7) Mr. Arnold served as a director until June 16, 2021.

In respect of his services as executive chair of our board, on January 3, 2022, we granted Mr. Smith an option to purchase 194,500 shares of our common stock and 97,250 restricted stock units.

Compensation committee interlocks and insider participation

None of the current members of our compensation committee has ever been an executive officer or employee of ours. None of our executive officers currently serves, or has served during the last completed fiscal year, on the compensation committee or Board of Directors of any other entity that has one or more executive officers serving as a member of our Board of Directors or compensation committee.

Security Ownership of Certain Beneficial Owners and Management

The following table sets forth information regarding the beneficial ownership of our common stock as of February 16, 2022 by (i) each person whom we know to beneficially own more than 5% of our outstanding common stock, or a 5% stockholder, (ii) each director, (iii) each Named Executive Officer and (iv) all current directors and executive officers as a group. Unless otherwise indicated, the address of each executive officer and director is c/o Solid Biosciences Inc., 141 Portland Street, Fifth Floor, Cambridge, MA 02139.

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The numberof shares of common stock “beneficially owned” by each stockholder is determined under rules issued by the SEC regarding the beneficial ownership of securities. This information is not necessarily indicative of beneficial ownership for any other purpose. Under these rules, beneficial ownership of shares of our common stock includes (1) any shares as to which the person or entity has sole or shared voting power or investment power and (2) any shares as to which the person or entity has the right to acquire beneficial ownership within 60 days after February 16, 2022. The percentage of beneficial ownership in the table below is based on 110,472,962shares of common stock deemed to be outstanding as of February 16, 2022.

Unless otherwise indicated below, and subject to community property laws where applicable, to our knowledge, all persons named in the table have sole voting and investment power with respect to their shares of common stock.

5% Stockholders:

Entities affiliated with RA Capital Management, L.P. (2) 12,367,873 11.20 %

Named Executive Officers and Directors:

Erin Powers Brennan (9) 81,250 *

Martin Freed, M.D., F.A.C.P. (12) 123,763 *

Adam Koppel, M.D., Ph.D. (16) 60,000 *

* Less than one percent.

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Securities Authorized for Issuance under Equity Compensation Plans

The following table provides information about our equity compensation plans as of December 31, 2021. As of December 31, 2021, we had three equity compensation plans, our 2018 Plan, our 2020 Plan and our ESPP, each of which was approved by our stockholders. We have also made inducement awards to certain new hires, which awards were not approved by our stockholders.

Equity compensation plans not approved by security holders 917,000 (3) 5.39 -

(1) Reflects shares issuable upon exercise of options and settlement of RSUs.

(2) The weighted-average exercise price does not include RSUs, which have no exercise price.

(3) Represents inducement stock option and restricted stock unit awards granted to employees in accordance with Nasdaq Listing Rule 5635(c)(4), with an exercise price equal to the closing price of our common stock on the date of grant, for inducement stock option awards, and each inducement award vesting over four years in equal annual installments from the applicable employee’s new hire date.

In addition to the executive officer and director compensation arrangements discussed above under “Compensation of our executive officers and directors,” we describe transactions since January 1, 2020 to which we have been or will be a participant, in which the amount involved in the transaction exceeds the lesser of $120,000 or 1% of our total assets at year-end for each of the last two completed fiscal years and in which any of our directors, executive officers or beneficial holders of more than 5% of any class of our capital stock, or 5% Security Holders, or any immediate family member of, or person sharing the household with, any of these individuals, had or will have a direct or indirect material interest.

Amended and restated registration rights agreement

We are party to an Amended and Restated Registration Rights Agreement, or the Registration Rights Agreement, dated March 29, 2017, with certain of our stockholders, or the Investors, which includes our 5% Security Holders and entities affiliated with certain of our directors. The Registration Rights Agreement provides the Investors the right, subject to certain conditions, to demand that we file a registration statement or to request that their shares be covered by a registration statement that we are otherwise filing.

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Private placement

On December 15, 2020, we entered into a definitive agreement with respect to the private placement of 24,324,320 shares of our common stock at a price per share of $3.70. We completed this private placement on December 15, 2020, resulting in approximately $90.0 million in gross proceeds to us, before deducting offering costs of $3.8 million. The number of shares that each of our directors, executive officers and holders of more than 5% of our voting securities purchased and the aggregate purchase price paid for such shares is set forth in the table below.

Name (1) Number of Shares of Common Stock Purchased Purchase Price

Public offering

In March 2021, we issued and sold 25,000,000 shares of our common stock, including the full exercise by the underwriters of an option to purchase additional shares of common stock, at a price per share of $5.75 in a follow-on public offering. We received net proceeds of approximately $134.9 million, after deducting underwriter discounts and commissions and offering expenses.The number of shares that each of our directors, executive officers and holders of more than 5% of our voting securities purchased and the aggregate purchase price paid for such shares is set forth in the table below.

Name (1) Number of Shares of Common Stock Purchased Purchase Price

(1)See “Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters” for more information about the shares held by the above identified entities.

Ultragenyx collaboration agreement

In October 2020, we entered into a collaboration and license agreement, or the Collaboration Agreement, with Ultragenyx Pharmaceutical Inc., or Ultragenyx, pursuant to which we granted Ultragenyx an exclusive worldwide license under certain intellectual property rights controlled by us. In connection with the execution of the Collaboration Agreement, we also entered into a stock purchase agreement with Ultragenyx, pursuant to which we issued and sold 7,825,797 shares of our common stock to Ultragenyx for an aggregate purchase price of approximately $40 million, resulting in Ultragenyx becoming a holder of more than 5% of our outstanding common stock. For a further description of the Collaboration Agreement with Ultragenyx, see “Business—Strategic partnerships and collaborations/licenses—Ultragenyx Collaboration Agreement.”

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Other arrangements

We employ Annie Ganot, one of our Co-Founders and the wife of Ilan Ganot, as Vice President, Patient Advocacy. Mr. Ganot is our CEO and a member of our Board of Directors. Ms. Ganot receives an annual salary and bonus payments of less than $251,000 in the aggregate.

In respect of his services as a consultant to us for the year ending December 31, 2020, (i) on January 2, 2020, we granted Andrey Zarur, a former member of our board, an option to purchase 10,000 shares of our common stock, and (ii) we paid him $58,000.

In connection with the termination of his employment, we entered into a consulting agreement with Jorge Quiroz, M.D., our former Chief Medical Officer, effective as of January 15, 2020, pursuant to which Dr. Quiroz assisted with the transition of his duties to our executive management team. Dr. Quiroz was compensated at a rate of $500 per hour for his services under the consulting agreement. The term of the consulting agreement continued until July 15, 2020.

In connection with the termination of his employment, we entered into a consulting agreement with Alvaro Amorrortu, our former Chief Operating Officer, effective as of January 15, 2020, pursuant to which Mr. Amorrortu assisted with the transition of his duties to our executive management team. Mr. Amorrortu was compensated at a rate of $500 per hour for his services under the consulting agreement. The term of the consulting agreement continued until July 15, 2020.

In respect of his services as a consultant to us for the year ended December 31, 2020, (i) on February 10, 2020, we granted Mr. Smith an option to purchase 60,000 shares of our common stock and (ii) on June 16, 2020, we granted Mr. Smith an option to purchase 200,000 shares of our common stock. In respect of his services as a consultant to us for the year ending December 31, 2021, on January 4, 2021, we granted Mr. Smith an option to purchase 389,000 shares of our common stock. In respect of his services as a consultant to us for the year ended December 31, 2021, on January 4, 2021, we granted Mr. Smith an option to purchase 389,000 shares of our common stock.

In November 2020, we entered into a consulting agreement with Danforth Advisors, LLC, or Danforth, an affiliate of Stephen DiPalma, our interim chief financial officer. Pursuant to the consulting agreement, Danforth provides us with the chief financial officer services of Mr. DiPalma, and other services, including financial planning, offering support and accounting services, in exchange for fees payable to Danforth based on hourly rates. We have paid Danforth approximately $0.7 million during the year ended December 31, 2021 and have made no payments during the year December 31, 2020. In accordance with the consulting agreement, in November 2020, we issued to Danforth a warrant to purchase 30,000 shares of our common stock at an exercise price per share of $3.29. The consulting agreement may be terminated by either party without cause upon 60 days’ prior written notice to the other party and with cause upon 30 days’ prior written notice to the other party.

Indemnification agreements

We have entered into agreements to indemnify our directors and executive officers. These agreements require us, among other things, to indemnify these individuals for certain expenses (including attorneys’ fees), judgments, fines and settlement amounts reasonably incurred by such persons in any action or proceeding, including any action by or in our right, on account of any services undertaken by any such person on behalf of our company or that person’s status as a member of our Board of Directors to the maximum extent allowed under Delaware law.

Policy for approval of related-person transactions

We have adopted a written related-person transaction policy that sets forth our procedures for the identification, review, consideration and approval or ratification of any transaction, arrangement or relationship in which we are a participant, the amount involved exceeds $120,000 and one of our executive officers, directors, director nominees or 5% stockholders (or their immediate family members), each of whom we refer to as a “related person,” has a direct or indirect material interest.

If a related person proposes to enter into such a transaction, arrangement or relationship, which we refer to as a “related-person transaction,” the related person must report the proposed related-person transaction to our general counsel. The policy calls for the proposed related-person transaction to be reviewed by and if deemed appropriate approved by, the audit committee of our Board of Directors. Whenever practicable, the reporting, review and approval will occur prior to entry into the transaction. If advance review and approval is not practicable, the audit committee will review and, in its discretion, may ratify the related-person transaction. The policy also permits the chair of the audit committee to review, and if deemed

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appropriate approve, proposed related-person transactions that arise between audit committee meetings, subject to ratification by the audit committee at its next meeting. Any related-person transactions that are ongoing in nature will be reviewed annually.

A related-person transaction reviewed under the policy will be considered approved or ratified if it is authorized by the audit committee after full disclosure of the related person’s interest in the transaction. As appropriate for the circumstances, the committee will review and consider:

• the related person’s interest in the related-person transaction;

• the approximate dollar amount involved in the related-person transaction;

• whether the transaction was undertaken in the ordinary course of our business;

The audit committee may approve or ratify the transaction only if the audit committee determines that, under all of the circumstances, the transaction is not inconsistent with our best interests. The audit committee may impose any conditions on the related-person transaction that it deems appropriate.

The policy provides that transactions involving compensation of executive officers will be reviewed and approved by the compensation committee of our Board of Directors in the manner specified in its charter.

Director independence