Solid Biosciences Announces Licensing Agreement with Andelyn Biosciences for the Use of Proprietary Next-Generation Capsid AAV-SLB101

- Non-exclusive license providing Solid’s proprietary, next-generation capsid, AAV-SLB101, to Andelyn Biosciences, a full-service cell and gene therapy Contract Development and Manufacturing Organization (CDMO) -

- Specific terms of the agreement have not been disclosed -

- AAV-SLB101 has been generally well tolerated in the 23 participants dosed in the Phase 1/2 INSPIRE DUCHENNE clinical trial as of a safety cutoff of October 31, 2025 -

- Solid continues to expand collaborative efforts for AAV-SLB101 with over 30 agreements including licenses executed-

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CHARLESTOWN, MA, November 17, 2025 – Solid Biosciences Inc.(Nasdaq: SLDB) (the “Company” or “Solid”), a life sciences company developing precision genetic medicines for neuromuscular and cardiac diseases, today announced a non-exclusive worldwide license and collaboration agreement with Andelyn Biosciences (Andelyn), a pioneering and patient-focused cell and gene therapyContract Development and Manufacturing Organization (CDMO), for the use of Solid’s proprietary, next-generation capsid, AAV-SLB101.

Under the terms of the agreement, Solid grants Andelyn a non-exclusive worldwide license to provide its gene therapy clients with access to utilize AAV-SLB101 in combination with Andelyn’s suspension and adherent modular platform process, the AAV Curator^® Platform, which brings a modular approach to gene therapy CMC processes by optimizing manufacturing and using configurable materials. Specific terms of the agreement have not been disclosed.
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AAV-SLB101 is Solid’s rationally designed capsid developed for enhanced skeletal muscle and cardiac tropism and reduced biodistribution to the liver. As of the recently reported safety cutoff of October 31, 2025, AAV-SLB101 has been generally well tolerated in the 23 pediatric participants who have been dosed in Solid’sPhase 1/2 INPSIRE DUCHENNE clinical trial (NCT06138639) evaluating investigational Duchenne muscular dystrophy gene therapy SGT-003, which utilizes AAV-SLB101. Robust cardiac and skeletal muscle transduction and biodistribution have been demonstrated in preclinical studies as well as in early clinical data from INSPIRE DUCHENNE.
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Bo Cumbo, President and CEO of Solid Biosciences, said, “We are excited to announce a new non-exclusive license for AAV-SLB101 with Andelyn Biosciences. This collaboration reflects our shared mission to accelerate the next generation of gene therapies built upon cutting-edge technologies designed to enhance safety and efficacy. With more than 30 agreements and licenses already in place for the use of AAV-SLB101, we expect our partnership with Andelyn to help trailblaze a brighter future for gene therapy. Andelyn’s pioneering and configurable CDMO model will accelerate our efforts to expand access to our proprietary capsid, enabling early-stage gene therapy programs to leverage a true next-generation capsid and benefit from the differentiated profile of AAV-SLB101.”

Matt Niloff, Chief Commercial Officer of Andelyn said, “We are eager to provide our clients with access to Solid’s novel capsid, AAV-SLB101. By integrating this next-generation technology into our AAV Curator^® Platform, we can offer an advanced gene therapy vector that has been clinically validated and ultimately may allow for faster and more cost-effective development. Our collaboration with Solid underscores our commitment to providing best-in-class solutions for our clients, empowering researchers and helping to advance transformative medicines for patients.”

About AAV-SLB101

AAV-SLB101 is a proprietary, rationally designed capsid developed for enhanced skeletal muscle and cardiac tropism and reduced liver uptake. With a robust preclinical package in mice and nonhuman primates, AAV-SLB101 has demonstrated increased transduction speed, enhanced skeletal and cardiac muscletropism, decreased liver biodistribution and improved efficiency when compared to first generation capsids. The incorporation of AAV-SLB101 into AAV delivered therapies has the potential to be a step forward in the treatment of neuromuscular and cardiac diseases. Solid Biosciences aims to licenseAAV-SLB101 broadly to both companies and academic institutions pursuing treatments for rare diseases. Solid has existing agreements, including licenses, with more than 30 corporations, institutions and academic labs for the use of AAV-SLB101.

About Solid Biosciences

Solid Biosciences is a precision genetic medicine company focused on advancing a portfolio of gene therapy candidates targeting rare neuromuscular and cardiac diseases, including SGT-003 for Duchenne muscular dystrophy(Duchenne), SGT-212 for Friedreich’s ataxia (FA), SGT-501 for catecholaminergicpolymorphic ventricular tachycardia (CPVT), SGT-601 for TNNT2-mediated dilated cardiomyopathy and additional fatal, genetic cardiac diseases. The Company is also focused on developing innovative libraries of genetic regulators and other enabling technologies with promising potential to significantly impact gene therapy delivery cross-industry. Solid is advancing its diverse pipeline and delivery platform in the pursuit of uniting experts in science, technology, disease management, and care. Patient-focused and founded by those directly impacted by Duchenne, Solid’s mission is to improve the daily lives of patients living with devastating rare diseases. For more information, please visit www.solidbio.com.

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About Andelyn Biosciences, Inc.

Andelyn Biosciences is a full-service cell and gene therapy CDMO focused on the development, characterization, and production of viral vectors for gene therapy. With more than 20 years of experience, Andelyn's deep scientific expertise has resulted in the production of cGMP material for more than 450 clinical batches and 75 global clinical trials. Operating out of its development and manufacturing facilities in Columbus, Ohio, Andelyn supports its clients in developing cell and gene therapies from concept through plasmid engineering and manufacturing, process and analytical development, and cGMP clinical and commercial manufacturing. Andelyn can accelerate programs and deliver high-quality products by developing and manufacturing processes on its configurable, data-driven AAV Curator^® Platform or tech transfer in an established client program. Capabilities include cGMP manufacturing for suspension processes up to a 2,000-liter and adherent processes. A rigorous quality system, regulatory support, and supply chain vertical integration further advantages clients in bringing their critical therapies to market. For more information, visit andelynbio.com.

For Andelyn media inquiries, please contact: Media@AndelynBiosciences.com

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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 future expectations, plans and prospects for the Company; the ability to successfully achieve and execute on the company’s goals, priorities and achieve key clinical milestones; the Company’s pipeline of capsid products, including SLB-101, and programs for neuromuscular and cardiac diseases, including its SGT-003 candidate and other clinical and pre-clinical programs and expectations for clinical development, initiation and enrollment in clinical trials, dosing, availability of clinical trial data and potential accelerated approval;; and other statements containing the words “anticipate,”“believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “plan,”“potential,” “predict,” “project,” “should,” “target,” “would,” “working” 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 the company’s ability to advance and license AAV-SLB101and advance SGT-003 and its other clinical and preclinical programs and capsidlibraries on the timelines expected or at all; obtain and maintain necessaryapprovals from the FDA and other regulatory authorities; replicate in clinicaltrials positive results found in preclinical studies and early-stage clinicaltrials of the company’s product candidates; obtain, maintain or protectintellectual property rights related to its capsid libraries and productcandidates; compete successfully with other companies that are seeking todevelop capsids, capsid libraries, Duchenne, Friedreich’s ataxia and otherneuromuscular and cardiac treatments and gene therapies;, achieve its otherbusiness objectives and continue as a going concern. For a discussion of otherrisks and uncertainties, and other important factors, any of which could causethe company’s actual results to differ from those contained in theforward-looking statements, see the “Risk Factors” section, as well asdiscussions of potential risks, uncertainties and other important factors, inthe company’s most recent filings with the Securities and Exchange Commission.In addition, the forward-looking statements included in this press releaserepresent the company’s views as of the date hereof and should not be reliedupon as representing the company’s views as of any date subsequent to the datehereof. The company anticipates that subsequent events and developments willcause the company's views to change. However, while the company may elect toupdate these forward-looking statements at some point in the future, thecompany specifically disclaims any obligation to do so.

Solid Biosciences Investor Contact:

Nicole Anderson
Director, InvestorRelations and Corporate Communications
Solid Biosciences Inc.
investors@solidbio.com
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MediaContact:
Glenn Silver
FINN Partners
glenn.silver@finnpartners.com