Solid Biosciences Inc. (NASDAQ:SLDB) Q1 2022 Results Conference Call April 27, 2022 8:00 AM ET Company Participants Caitlin Lowie - VP, Communications and IR Ilan Ganot - Co-Founder, President and CEO Dr. Joel Schneider - COO Dr. Carl Morris - Chief Scientific Officer Dr. Roxana Donisa Dreghici - SVP and Head, Clinical Development Conference Call Participants Gena Wang - Barclays Joseph Schwartz - SVB Securities Allison Bratzel - Piper Sandler Anupam Rama - JP Morgan Maury Raycroft - Jefferies Operator Ladi ...

PART I. FINANCIAL INFORMATION [Item 1. Financial Statements (Unaudited)](index=3&type=section&id=Item%201.%20Financial%20Statements%20(Unaudited)) Q1 2022 net loss of $25.3 million, decreased assets, and April 2022 restructuring with 35% workforce reduction Condensed Consolidated Balance Sheet Data (in thousands) | Account | March 31, 2022 | December 31, 2021 | | :--- | :--- | :--- | | Cash and cash equivalents | $129,711 | $119,136 | | Available-for-sale securities | $50,339 | $88,643 | | **Total Assets** | **$207,556** | **$232,380** | | Total current liabilities | $21,744 | $23,601 | | **Total Liabilities** | **$22,045** | **$24,169** | | **Total Stockholders' Equity** | **$185,511** | **$208,211** | Condensed Consolidated Statements of Operations (in thousands) | Account | Three Months Ended March 31, 2022 | Three Months Ended March 31, 2021 | | :--- | :--- | :--- | | Collaboration revenue - related party | $1,925 | $3,335 | | Research and development | $19,945 | $14,206 | | General and administrative | $7,352 | $6,015 | | **Loss from operations** | **($25,372)** | **($16,886)** | | **Net loss** | **($25,328)** | **($16,900)** | | **Net loss per share** | **($0.22)** | **($0.19)** | Condensed Consolidated Statements of Cash Flows (in thousands) | Activity | Three Months Ended March 31, 2022 | Three Months Ended March 31, 2021 | | :--- | :--- | :--- | | Net cash used in operating activities | ($27,190) | ($21,366) | | Net cash provided by (used in) investing activities | $37,743 | ($35) | | Net cash provided by financing activities | $22 | $135,154 | - In April 2022, the company implemented a corporate restructuring to prioritize its key programs, SGT-001 and SGT-003, involving a headcount reduction of approximately **35%**, with estimated restructuring costs of **$1.7 million** for severance and employee benefits[83](index=83&type=chunk) [Management's Discussion and Analysis of Financial Condition and Results of Operations](index=19&type=section&id=Item%202.%20Management%27s%20Discussion%20and%20Analysis%20of%20Financial%20Condition%20and%20Results%20of%20Operations) Management discusses strategic shifts, including a 35% workforce reduction to extend cash runway, and Q1 2022 net loss of $25.3 million from increased R&D - The company's lead product candidate is **SGT-001**, a gene transfer therapy for Duchenne, with enrollment in the Phase I/II **IGNITE DMD** trial complete and two-year data suggesting **durable benefit**[90](index=90&type=chunk)[91](index=91&type=chunk)[94](index=94&type=chunk) - In **April 2022**, the company announced a **strategic shift** to a commercially scaled, transient transfection-based manufacturing process for **SGT-001** and narrowed its R&D focus to **SGT-001**, **SGT-003**, and next-generation capsids[92](index=92&type=chunk) - As part of the **April 2022** reorganization, the company reduced its headcount by approximately **35%**, expected to extend the cash runway into the **second quarter of 2024**, based on **$180.1 million** in cash, cash equivalents, and available-for-sale securities as of March 31, 2022[93](index=93&type=chunk)[102](index=102&type=chunk) Comparison of Operating Results (in thousands) | Line Item | Q1 2022 | Q1 2021 | Change | % Change | | :--- | :--- | :--- | :--- | :--- | | Collaboration Revenue | $1,925 | $3,335 | ($1,410) | (42%) | | R&D Expenses | $19,945 | $14,206 | $5,739 | 40% | | G&A Expenses | $7,352 | $6,015 | $1,337 | 22% | | **Net Loss** | **($25,328)** | **($16,900)** | **($8,428)** | **50%** | Research & Development Expenses Breakdown (in thousands) | Program | Q1 2022 | Q1 2021 | Change | % Change | | :--- | :--- | :--- | :--- | :--- | | SGT-001 | $5,422 | $6,173 | ($751) | (12)% | | SGT-003 and other programs | $3,364 | $192 | $3,172 | 1652% | | Unallocated R&D | $11,159 | $7,841 | $3,318 | 42% | | **Total R&D Expenses** | **$19,945** | **$14,206** | **$5,739** | **40%** | [Quantitative and Qualitative Disclosures About Market Risk](index=29&type=section&id=Item%203.%20Quantitative%20and%20Qualitative%20Disclosures%20About%20Market%20Risk) The company faces market risk from interest rate changes on short-term investments, with a 10% change not materially impacting financial position - The company's primary market risk exposure is **interest income sensitivity** related to its cash equivalents and available-for-sale securities[145](index=145&type=chunk) - Due to the short-term nature of its investment portfolio, a **10%** change in interest rates is **not expected to materially impact** the company's financial condition[145](index=145&type=chunk) [Controls and Procedures](index=29&type=section&id=Item%204.%20Controls%20and%20Procedures) Management concluded disclosure controls were effective as of March 31, 2022, with no material changes to internal control over financial reporting - As of March 31, 2022, the President and Chief Executive Officer and the interim Chief Financial Officer concluded that the company's disclosure controls and procedures were **effective at the reasonable assurance level**[146](index=146&type=chunk) - **No material changes** to the company's internal control over financial reporting occurred during the first quarter of 2022[147](index=147&type=chunk) PART II. OTHER INFORMATION [Legal Proceedings](index=30&type=section&id=Item%201.%20Legal%20Proceedings) The company reports that it is not a party to any material legal proceedings - As of the filing date, the company states there are **no material legal proceedings**[150](index=150&type=chunk) [Risk Factors](index=30&type=section&id=Item%201A.%20Risk%20Factors) The company faces significant financial, developmental, manufacturing, commercial, and IP risks, including a history of losses and novel gene therapies - **Financial Risks:** The company has a history of significant net losses (**$25.3M** in Q1 2022) and an accumulated deficit of **$502.1M**, and will **require additional funding** to continue operations beyond its current cash runway[154](index=154&type=chunk)[158](index=158&type=chunk) - **Clinical Development Risks:** SGT-001 and SGT-003 are based on **novel gene transfer technology**, making development time and cost difficult to predict, and the IGNITE DMD trial was previously placed on **clinical hold** by the FDA[153](index=153&type=chunk)[172](index=172&type=chunk)[175](index=175&type=chunk) - **Manufacturing & Commercialization Risks:** The company has **limited gene transfer manufacturing experience** and **relies on third parties**, posing risks of performance, regulatory compliance, and **supply disruption**, with a planned shift to a new manufacturing process for SGT-001 potentially requiring additional studies[155](index=155&type=chunk)[249](index=249&type=chunk)[256](index=256&type=chunk) - **Intellectual Property Risks:** The business **heavily relies on in-licensed patents**, which the company may **not control the prosecution and enforcement** of, and they could be **challenged, invalidated, or circumvented** by competitors[155](index=155&type=chunk)[328](index=328&type=chunk)[334](index=334&type=chunk) - **Competition Risk:** The company faces **significant competition** from **larger, better-funded companies** like Pfizer and Sarepta Therapeutics, which have Duchenne gene therapy candidates in **later stages of clinical development (Phase III)**[235](index=235&type=chunk)[236](index=236&type=chunk) [Unregistered Sales of Equity Securities and Use of Proceeds](index=88&type=section&id=Item%202.%20Unregistered%20Sales%20of%20Equity%20Securities%20and%20Use%20of%20Proceeds) On January 3, 2022, the company issued an inducement grant of 131,400 stock options and 65,700 restricted stock units - On **January 3, 2022**, the company granted a new employee an option for **131,400 shares** and **65,700 restricted stock units** as an **inducement award** under Nasdaq Listing Rule 5635(c)(4)[403](index=403&type=chunk) [Other Information](index=88&type=section&id=Item%205.%20Other%20Information) On April 25, 2022, the Board approved a restructuring plan with a 35% workforce reduction, costing $1.7 million, to extend cash runway into Q2 2024 - On **April 25, 2022**, the Board approved a restructuring plan to reduce the workforce by approximately **35%** to prioritize key programs and extend the cash runway into **Q2 2024**[405](index=405&type=chunk)[406](index=406&type=chunk) - The company estimates total restructuring costs of approximately **$1.7 million**, primarily for severance and employee termination benefits, to be paid mostly during 2022[407](index=407&type=chunk) - A **retention program** was approved for remaining key employees, including cash bonuses and stock option grants for the Chief Legal Officer and Chief Scientific Officer[408](index=408&type=chunk) [Exhibits](index=89&type=section&id=Item%206.%20Exhibits) The section lists exhibits filed with Form 10-Q, including CEO/CFO certifications and Inline XBRL documents for financial reporting - The filing includes **CEO and CFO certifications** pursuant to Sections 302 and 906 of the Sarbanes-Oxley Act[410](index=410&type=chunk) - **Inline XBRL** Instance, Schema, and other related taxonomy documents are included as exhibits for interactive data[410](index=410&type=chunk) [Signatures](index=90&type=section&id=Signatures) The report was signed on April 27, 2022, by Ilan Ganot (CEO) and Stephen DiPalma (Interim CFO) - The report was signed on **April 27, 2022**, by **Ilan Ganot (CEO)** and **Stephen DiPalma (Interim CFO)**[413](index=413&type=chunk)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2021 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number 001-38360 Solid Biosciences Inc. (Exact name of Registrant as specified in its Charter) (State or other jurisdiction of incorporation or ...

[PART I. FINANCIAL INFORMATION](index=2&type=section&id=PART%20I.%20FINANCIAL%20INFORMATION) [Item 1. Financial Statements (Unaudited)](index=2&type=section&id=Item%201.%20Financial%20Statements%20(Unaudited)) This section presents unaudited financial statements reflecting increased equity from a public offering and new collaboration revenue [Condensed Consolidated Balance Sheets](index=3&type=section&id=Condensed%20Consolidated%20Balance%20Sheets) The balance sheet reflects a substantial increase in total assets and stockholders' equity, driven by a public offering Condensed Consolidated Balance Sheet Highlights (in thousands) | Account | Sep 30, 2021 | Dec 31, 2020 | | :--- | :--- | :--- | | **Assets** | | | | Cash and cash equivalents | $109,676 | $154,744 | | Available-for-sale securities | $120,084 | $— | | **Total current assets** | **$238,810** | **$158,901** | | **Total assets** | **$248,986** | **$171,169** | | **Liabilities & Equity** | | | | Total current liabilities | $22,542 | $24,480 | | **Total liabilities** | **$25,623** | **$39,083** | | **Total stockholders' equity** | **$223,363** | **$132,086** | [Condensed Consolidated Statements of Operations](index=4&type=section&id=Condensed%20Consolidated%20Statements%20of%20Operations) Operations show new collaboration revenue and reduced R&D expenses, resulting in a lower net loss compared to the prior year Statement of Operations Summary (in thousands, except per share data) | Metric | Q3 2021 | Q3 2020 | 9 Months 2021 | 9 Months 2020 | | :--- | :--- | :--- | :--- | :--- | | Collaboration revenue | $3,537 | $— | $10,466 | $— | | Research and development | $14,425 | $16,045 | $44,144 | $49,158 | | General and administrative | $7,143 | $5,181 | $19,924 | $15,957 | | Loss from operations | $(18,031) | $(21,226) | $(53,602) | $(67,059) | | **Net loss** | **$(17,983)** | **$(21,246)** | **$(53,578)** | **$(66,927)** | | Net loss per share | $(0.16) | $(0.44) | $(0.51) | $(1.39) | [Condensed Consolidated Statements of Cash Flows](index=8&type=section&id=Condensed%20Consolidated%20Statements%20of%20Cash%20Flows) Cash flows indicate significant financing from a stock issuance, offset by cash used for investments and operations Cash Flow Summary (Nine Months Ended Sep 30, in thousands) | Cash Flow Activity | 2021 | 2020 | | :--- | :--- | :--- | | Net cash used in operating activities | $(56,890) | $(57,906) | | Net cash (used in) provided by investing activities | $(121,262) | $6,660 | | Net cash provided by financing activities | $134,919 | $— | | **Net decrease in cash, cash equivalents and restricted cash** | **$(43,233)** | **$(51,246)** | [Notes to the Condensed Consolidated Financial Statements](index=9&type=section&id=Notes%20to%20the%20Condensed%20Consolidated%20Financial%20Statements) Notes detail the IGNITE DMD trial status, the Ultragenyx collaboration, and the company's sufficient liquidity for the next twelve months - The company's lead product candidate, SGT-001, is in a Phase I/II clinical trial (IGNITE DMD) which was previously on clinical hold by the FDA and resumed patient treatment in February 2021[25](index=25&type=chunk) - The company believes its cash, cash equivalents, and available-for-sale securities of **$229.8 million** as of September 30, 2021, are sufficient to fund operations for at least twelve months[30](index=30&type=chunk) - The collaboration with Ultragenyx resulted in recognizing **$10.5 million** of related party collaboration revenue for the nine months ended September 30, 2021[61](index=61&type=chunk) - In March 2021, the company completed a public offering of 25,000,000 shares of common stock, receiving net proceeds of approximately **$134.9 million**[76](index=76&type=chunk)[109](index=109&type=chunk) [Management's Discussion and Analysis of Financial Condition and Results of Operations](index=20&type=section&id=Item%202.%20Management's%20Discussion%20and%20Analysis%20of%20Financial%20Condition%20and%20Results%20of%20Operations) Management discusses the clinical progress of SGT-001, financial performance improvements, and a cash runway into Q2 2023 [Overview](index=20&type=section&id=MD%26A%20Overview) The company focuses on its SGT-001 trial for Duchenne, manages a recent adverse event, and advances its next-gen SGT-003 candidate - The eighth patient in the IGNITE DMD trial experienced a **serious adverse event**, which has since fully resolved, and a strengthened risk mitigation plan has been submitted to the FDA[91](index=91&type=chunk)[92](index=92&type=chunk)[93](index=93&type=chunk) - Long-term biopsy data from patients 4-6 demonstrated **durable and widespread expression of microdystrophin protein** at 1 to 2 years post-dosing[95](index=95&type=chunk) - The company is advancing a next-generation program, SGT-003, and is targeting an **IND submission in early 2023**[99](index=99&type=chunk) - As of September 30, 2021, the company had cash, cash equivalents, and available-for-sale securities of **$229.8 million**, expected to fund operations into the second quarter of 2023[110](index=110&type=chunk) [Results of Operations](index=27&type=section&id=MD%26A%20Results%20of%20Operations) Financial results improved due to new collaboration revenue and lower R&D costs, despite an increase in G&A expenses Comparison of Results (in thousands) | Metric | 9 Months 2021 | 9 Months 2020 | Change | | :--- | :--- | :--- | :--- | | Collaboration Revenue | $10,466 | $— | $10,466 | | Research & Development | $44,144 | $49,158 | $(5,014) | | General & Administrative | $19,924 | $15,957 | $3,967 | | **Net Loss** | **$(53,578)** | **$(66,927)** | **$13,349** | - The **$5.0 million decrease in R&D expenses** was primarily due to a $6.4 million decrease in SGT-001 manufacturing costs, partially offset by higher personnel expenses[137](index=137&type=chunk) - The **$3.9 million increase in G&A expenses** was due to a $2.2 million increase in corporate expenses and a $1.7 million increase in personnel-related expenses[138](index=138&type=chunk) [Liquidity and Capital Resources](index=28&type=section&id=MD%26A%20Liquidity%20and%20Capital%20Resources) The company's liquidity is strong following recent equity financing, providing a cash runway into the second quarter of 2023 - The company raised net proceeds of approximately **$134.9 million** from a public offering in March 2021[147](index=147&type=chunk) - As of September 30, 2021, the company had cash, cash equivalents and available-for-sale securities of **$229.8 million** and no debt outstanding[148](index=148&type=chunk) - The company expects its current cash position will be sufficient to fund operations into the **second quarter of 2023**, but will need to raise additional funds to operate beyond that time[155](index=155&type=chunk) [Quantitative and Qualitative Disclosures About Market Risk](index=32&type=section&id=Item%203.%20Quantitative%20and%20Qualitative%20Disclosures%20About%20Market%20Risk) The company's primary market risk from interest rate changes on its short-term investments is considered immaterial - The company's primary market risk is **interest rate sensitivity** on its cash equivalents and available-for-sale securities[165](index=165&type=chunk) - Due to the short-term nature of its investment portfolio, the company does not expect a 10% change in interest rates to have a **material impact** on its financial position[165](index=165&type=chunk) [Controls and Procedures](index=32&type=section&id=Item%204.%20Controls%20and%20Procedures) Management concluded that disclosure controls and procedures were effective, with no material changes to internal controls - Management concluded that as of September 30, 2021, the company's disclosure controls and procedures were **effective at the reasonable assurance level**[166](index=166&type=chunk) - **No material changes** in internal control over financial reporting occurred during the three months ended September 30, 2021[167](index=167&type=chunk) [PART II. OTHER INFORMATION](index=32&type=section&id=PART%20II.%20OTHER%20INFORMATION) [Legal Proceedings](index=34&type=section&id=Item%201.%20Legal%20Proceedings) The company is not currently involved in any material legal proceedings - As of September 30, 2021, the company is **not aware of any material legal proceedings**[82](index=82&type=chunk)[170](index=170&type=chunk) [Risk Factors](index=34&type=section&id=Item%201A.%20Risk%20Factors) Key risks include a history of net losses, clinical development challenges, manufacturing reliance, and intellectual property dependencies - Financial risks include a history of significant net losses (**$458.1M accumulated deficit**) and the need for additional funding beyond Q2 2023[174](index=174&type=chunk)[177](index=177&type=chunk)[179](index=179&type=chunk) - **Clinical development risks are high**, highlighted by the previous FDA clinical hold on the IGNITE DMD trial for SGT-001 due to a serious adverse event[192](index=192&type=chunk) - The company has limited manufacturing experience and **relies on third parties**, facing risks of production problems, delays, and regulatory compliance issues[266](index=266&type=chunk) - The business is **heavily dependent on intellectual property licensed from universities**, which imposes diligence obligations and may be subject to government 'march-in' rights[347](index=347&type=chunk)[385](index=385&type=chunk) [Unregistered Sales of Equity Securities and Use of Proceeds](index=88&type=section&id=Item%202.%20Unregistered%20Sales%20of%20Equity%20Securities%20and%20Use%20of%20Proceeds) The company issued unregistered stock options as inducement awards to two new employees during the third quarter of 2021 - On July 1, 2021, granted an option to purchase **235,000 shares** at an exercise price of $3.77 per share to a new employee[424](index=424&type=chunk) - On August 16, 2021, granted an option to purchase **118,000 shares** at an exercise price of $2.51 per share to a new employee[425](index=425&type=chunk) [Exhibits](index=89&type=section&id=Item%206.%20Exhibits) This section lists all exhibits filed with the report, including stock plans, agreements, and officer certifications [Signatures](index=90&type=section&id=Signatures) The report is formally signed and authorized by the company's CEO and interim CFO

© 2021 Solid Biosciences1 Solid Biosciences Corporate OverviewOctober 2021 Forward-Looking Statements This presentation contains "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995, including statements regarding the Company's IGNITE DMD clinical trial, ability of the Company to continue dosing patients in the IGNITE DMD trial, the implication of interim clinical data, the safety or potential treatment benefits of SGT-001 in patients with Duchenne, the Com ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2021 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-38360 Solid Biosciences Inc. (Exact Name of Registrant as Specified in its Charter) WASHINGTON, DC 20549 Delaware 90-0943402 (State or other jurisdicti ...

Financial Data and Key Metrics Changes - In Q1 2021, the company closed a public offering resulting in gross proceeds of approximately $143.8 million before deductions, strengthening its balance sheet [33] - The company ended the quarter with $268.5 million in cash and cash equivalents, which is expected to fund operating expenses into Q4 2022 [34] Business Line Data and Key Metrics Changes - Two patients were dosed in the IGNITE DMD trial this quarter using SGT-001 produced with an improved manufacturing process [7] - Patient 8 experienced a serious adverse event (SAE) but has since been discharged, with lab values trending towards normal [7][13] Market Data and Key Metrics Changes - The company is advancing its preclinical pipeline with the nomination of SGT-003 as the next development candidate, which combines a novel capsid and proprietary microdystrophin construct [9][30] Company Strategy and Development Direction - The company is focused on expanding its pipeline with differentiated gene therapies, including SGT-003, which aims to enhance delivery to muscle cells [10][30] - Collaboration with Ultragenyx is ongoing to optimize candidate vectors for additional Duchenne gene therapies [31][32] Management's Comments on Operating Environment and Future Outlook - Management expressed confidence in the long-term potential of SGT-001 based on encouraging long-term biopsy data and clinical biomarker trends [26][37] - The company remains committed to the Duchenne community and aims to advance therapies that improve patient lives [38] Other Important Information - The company is working closely with its Data Safety Monitoring Board (DSMB) to evaluate data and ensure patient safety before continuing dosing in the IGNITE DMD trial [12][14] Q&A Session Summary Question: Long-term expression data and its correlation with clinical benefits - Management acknowledged the correlation observed but emphasized the need for more data to establish specific relationships [42][44] Question: Dosing path for additional patients and details on SAE - Management confirmed that the SAE was an inflammatory response and that they are working with the DSMB to evaluate the situation before proceeding with further dosing [47][48] Question: Additional information on Patient 8's inflammatory response - Management indicated that they are still evaluating the specifics of Patient 8's response and have seen laboratory evidence of complement activation in all treated patients [51][53] Question: Timeline for additional functional data from Patients 7 and 8 - Management stated that functional data from Patient 7 will take time to analyze due to the influence of steroids and has not provided a specific timeline [63] Question: Factors influencing long-term data variability among patients - Management noted that variability is expected in biological assays and that they are investigating potential mechanisms behind the differences observed [65][66] Question: Potential changes to the protocol to reduce inflammatory events - Management is exploring various options for protocol modifications to enhance patient safety, but no specific changes have been determined yet [75] Question: Sharing of SAE details with FDA and DSMB - Management confirmed that they have shared details of the SAE with both the FDA and DSMB and are in ongoing discussions [77]

WASHINGTON, DC 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2021 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to UNITED STATES SECURITIES AND EXCHANGE COMMISSION Commission File Number: 001-38360 Solid Biosciences Inc. (Exact Name of Registrant as Specified in its Charter) Delaware 90-0943402 (State or other jurisdict ...

SGT-001 Interim Clinical Results From IGNITE-DMD Ilan Ganot, Co-founder, President, and CEO March 15, 2021 Forward-Looking Statements This presentation contains "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995, including statements regarding the Company's IGNITE DMD clinical trial, ability of the Company to continue dosing patients in the IGNITE DMD trial, the implication of interim clinical data, the safety or potential treatment benefits of SGT-001 in ...

FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 For the fiscal year ended December 31, 2020 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number 001-38360 Solid Biosciences Inc. (Exact name of Registrant as specified in its Charter) Delaware 90-0943402 (State or other jurisdiction ...