UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of report (Date of earliest event reported): August 14, 2019

Solid Biosciences Inc.

(Exact Name of Registrant as Specified in Charter)

141 Portland Street, Fifth Floor

Cambridge, MA 02139

(Address of Principal Executive Offices) (Zip Code)

Registrant’s telephone number, including area code: (617) 337-4680

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company  ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ☒

Securities registered pursuant to Section 12(b) of the Act:

On August 14, 2019, Solid Biosciences Inc. announced its financial results for the second quarter ended June 30, 2019. The full text of the press release issued in connection with the announcement is furnished as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference.

The information provided under Item 2.02 of this Current Report on Form 8-K (including Exhibit 99.1) shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such a filing.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Exhibit 99.1

Solid Biosciences Reports Second Quarter 2019 Financial Results and Provides Business Update

– Additional patient dosed at 2E14 vg/kg in second cohort of IGNITE DMD trial –

– Study protocol amended to expedite clinical execution of SGT-001 –

– Recent $60M capital raise extends runway into the fourth quarter of 2020 –

Cambridge, MA – August 14, 2019 – Solid Biosciences Inc. (Nasdaq: SLDB) today reported financial results for the second quarter ended June 30, 2019 and provided a business update.

“We continue to execute on our mission to bring transformative therapies to patients with Duchenne muscular dystrophy, and we have taken several steps towards reaching our goal,” said Ilan Ganot, Chief Executive Officer, President and Co-Founder of Solid Biosciences. “We have amended the IGNITE-DMD protocol to expedite our clinical path evaluating our SGT-001 gene transfer candidate and have treated a second patient in our higher dose cohort. We also bolstered our financial resources and extended our runway. Looking forward, we continue to anticipate providing a data update from the IGNITE DMD clinical trial in the months ahead.”

Recent Developments

Financial Highlights

Research and development expenses for the second quarter of 2019 were $21.6 million, compared to $13.6 million for the second quarter of 2018. The increase was primarily attributable to compensation and other costs associated with additional headcount, as well as facility costs and increased costs related to the clinical development and manufacturing activities for SGT-001.

General and administrative expenses for the second quarter of 2019 were $5.4 million, compared to $4.6 million for the second quarter of 2018. The increase was primarily attributable to increased personnel costs, partially offset by a decrease in other corporate expenses.

Net loss for the second quarter of 2019 was $26.5 million, compared to $18.0 million for the second quarter of 2018.

Solid had $67.4 million in cash, cash equivalents and available-for-sale securities as of June 30, 2019, compared to $122.5 million as of December 31, 2018. Including the proceeds from the July 2019 private placement, Solid expects that that company has sufficient capital to fund its operations into the fourth quarter of 2020.

About SGT-001

Solid’s lead candidate, SGT-001, is a novel adeno-associated viral (AAV) vector-mediated gene transfer under investigation for its ability to address the underlying genetic cause of Duchenne muscular dystrophy (DMD), mutations in the dystrophin gene that result in the absence or near-absence of dystrophin protein. SGT-001 is a systemically administered candidate that delivers a synthetic dystrophin transgene, called microdystrophin, to the body. This microdystrophin encodes for a functional protein surrogate that is expressed in muscles and stabilizes essential associated proteins, including neuronal nitric oxide synthase (nNOS). SGT-001 utilizes AAV9, which has an affinity for muscle and is currently being evaluated in multiple clinical programs in other indications. Data from Solid’s preclinical program suggest that SGT-001 has the potential to slow or stop the progression of DMD, regardless of genetic mutation or disease stage.

SGT-001 is based on pioneering research in dystrophin biology by Dr. Jeffrey Chamberlain of the University of Washington and Dr. Dongsheng Duan of the University of Missouri. SGT-001 has been granted Rare Pediatric Disease Designation, or RPDD, and Fast Track Designation in the United States and Orphan Drug Designations in both the United States and European Union.

About Solid Biosciences

Solid Biosciences is a life science company focused solely on finding meaningful therapies for Duchenne muscular dystrophy (DMD). Founded by those touched by the disease, Solid is a center of excellence for DMD, bringing together experts in science, technology and care to drive forward a portfolio of candidates that have life-changing potential. Solid is progressing programs across four scientific platforms: Corrective Therapies, Disease-Modifying Therapies, Disease Understanding and Assistive Devices. For more information, please visit www.solidbio.com.

Forward-Looking Statements

This press release contains “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, including statements regarding our expectations regarding the IGNITE DMD clinical trial, the safety or potential efficacy of SGT-001, the sufficiency of our cash, cash equivalents and investments to fund our operation and other statements containing the words “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “should,” “target,” “would,” and similar expressions. Any forward-looking statements are based on management’s current expectations of future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in, or implied by, such forward-looking statements. These risks and uncertainties include, but are not limited to, risks associated with Solid’s ability to obtain and maintain necessary approvals from the FDA and other regulatory authorities and investigational review boards at clinical trial sites; enroll patients in its clinical trials; continue to advance SGT-001 in clinical trials, including to proceed with dose escalation of IGNITE DMD; replicate in clinical trials positive results found in preclinical studies and earlier stages of clinical development; advance the development of its product candidates under the timelines it anticipates in current and future clinical trials; successfully scale its manufacturing process; obtain, maintain or protect intellectual property rights related to its product candidates; compete successfully with other companies that are seeking to develop DMD treatments and gene therapies; manage expenses; and raise the substantial additional capital needed to achieve its business objectives. For a discussion of

other risks and uncertainties, and other important factors, any of which could cause the Company’s actual results to differ from those contained in the forward-looking statements, see the “Risk Factors” section, as well as discussions of potential risks, uncertainties and other important factors, in the Company’s most recent filings with the Securities and Exchange Commission. In addition, the forward-looking statements included in this press release represent the Company’s views as of the date hereof and should not be relied upon as representing the Company’s views as of any date subsequent to the date hereof. The Company anticipates that subsequent events and developments will cause the Company’s views to change. However, while the Company may elect to update these forward-looking statements at some point in the future, the Company specifically disclaims any obligation to do so.

Solid Biosciences Inc.

Condensed Consolidated Statements of Operations

(unaudited, in thousands, except share and per share data)

Solid Biosciences Inc.

Condensed Consolidated Balance Sheets

(unaudited, in thousands, except share and per share data)

Contact:

Geoffrey M. Grande, CFA

+1 617-766-3398

investors@solidbio.com