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© 2026 Solid Biosciences Corporate Presentation January 2026
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© 2026 Solid Biosciences 2 Cautionary Note Regarding Forward Looking Statements This presentation 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 key clinical and preclinical milestones; strategies and expectations for the company’s SGT-003, SGT-212, SGT-501 and SGT-601 programs; expectations for additional site activations, planned enrollment, planned regulatory interactions and the potential approval pathways for SGT-003; timing of planned clinical trials of SGT-501; 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 SGT-003, SGT-212, SGT-501, SGT-601 and other preclinical programs, capsid libraries and other enabling technologies on the timelines expected or at all; obtain and maintain necessary approvals from the FDA and other regulatory authorities; replicate in clinical trials positive results found in preclinical studies and early-stage clinical trials of the company’s product candidates; obtain, maintain or protect intellectual property rights related to its product candidates; replicate preliminary or interim data from early-stage clinicals trials in the final data of such trials; compete successfully with other companies that are seeking to develop Duchenne, FA, CPVT and other neuromuscular and cardiac treatments and gene therapies; manage expenses; and raise the substantial additional capital needed, on the timeline necessary, to continue development of SGT-003, SGT-212, SGT-501, SGT-601 and other candidates, achieve its other business objectives and continue as a going concern. 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. This presentation contains estimates and other statistical data made by independent parties and by us relating to market size and other data about our industry. This data involves a number of assumptions and limitations, and you are cautioned not to give undue weight to such data and estimates. In addition, projections, assumptions and estimates of our future performance and the future performance of the markets in which we operate are necessarily subject to a high degree of uncertainty and risk.
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© 2026 Solid Biosciences PROGRAM INDICATION RESEARCH / DISCOVERY PRECLINICAL PHASE 1/2 PHASE 3 WORLDWIDE RIGHTS Neuromuscular SGT-003 Duchenne muscular dystrophy SGT-212 Friedreich’s ataxia (FA) Cardiac SGT-501 RYR2-Mediated CPVT CASQ2-Mediated CPVT SGT-601 TNNT2 DCM SGT-401 BAG3-Mediated DCM SGT-701 RBM20 DCM Mayo Clinic Collaboration Six Undisclosed Targets Platform Capsid Library1 Cardiac & NM 3 Notes: In 2020, Solid entered into a collaboration agreement with Ultragenyx for the development of UX810, a next generation Duchenne construct comprised of Solid’s proprietary nNOS microdystrophin and Ultragenyx’s PinnacleTM PCL manufacturing platform for use with AAV8 and Clade E variants thereof. Solid has the option to co-fund collaboration programs in return for a profit share or increased royalty payments at proof-of-concept. 1. Cardiac Capsid Library currently in NHPs, Mice and Pigs. Shaping a Brighter Future for Tomorrow’s Gene Therapies INSPIRE DUCHENNE IMPACT DUCHENNE ARTEMIS FALCON
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© 2026 Solid Biosciences 4 Consistent Execution in 2025 Positions Solid for a Pivotal 2026 2025 (achievements) First-in-human data & interim update from Phase 1/2 INSPIRE DUCHENNE Exceeded 30+ executed licenses and agreements announced as of Nov. 3 Initial and interim Phase 1/2 INSPIRE DUCHENNE data Exceeded INSPIRE DUCHENNE participant enrollment targets Activated sites & enrolled first participant in ex-US Phase 3 trial, IMPACT DUCHENNE U.K. Innovative Licensing and Access Pathway (ILAP) designation granted Announced FDA IND clearance Granted FDA Fast Track, Rare Pediatric Disease and Orphan Drug Disease designations Activated sites & enrolled first participant in Phase 1b clinical trial, FALCON Announced FDA IND clearance and Health Canada CTA approval Granted FDA Fast Track designation Activated sites in Phase 1b clinical trial, ARTEMIS Lead Programs AAV-SLB101 Proprietary Cardiac & Neuromuscular Capsid SGT-003 Duchenne Muscular Dystrophy (Duchenne) SGT-212 Friedreich’s ataxia (FA) SGT-501 Catecholaminergic polymorphic ventricular tachycardia (CPVT)
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© 2026 Solid Biosciences Lead Programs 5 2026: A Potentially Transformational Year 4 clinical programs in 3 markets with significant opportunity with multiple key anticipated clinical catalysts AAV-SLB101 Capsid Library SGT-003 Duchenne SGT-212 FA SGT-501 CPVT 2026 (anticipated milestones) • Continued out-licensing efforts designed to seed early-stage cardiac & neuromuscular research • Creation of proprietary next-generation capsids • Q1 2026: First participant has been enrolled, with initiation of dosing expected in Phase 3 IMPACT DUCHENNE trial • H1 2026: Planned interactions with U.S. FDA for potential alignment on approval pathway • Mid-2026: Expected update on FDA interactions, including potential accelerated approval pathway1; additional data expected from INSPIRE DUCHENNE trial Jan 2026: First participant dosed in Phase 1b FALCON trial • H2 2026: Initial data expected from FALCON trial2 • Q1 2026: First participant expected to be dosed in Phase 1b ARTEMIS trial • H2 2026: Initial safety data expected from ARTEMIS trial2 Establish a potential best-in-class Duchenne gene therapy Building next-generation technology infrastructure Only therapy in development designed to address neurologic & cardiac manifestations Potential first-in-class therapy with significant market opportunity 1. Expected timing, subject to scheduling and formal receipt of meeting minutes. 2. Subject to participant enrollment
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© 2026 Solid Biosciences Investigational Duchenne Muscular Dystrophy (Duchenne) Gene Therapy SGT-003
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© 2026 Solid Biosciences DAPC=dystrophin-associated protein complex; LVEF=left ventricular ejection fraction; TAM=total addressable market. 1. The 33rd participant was dosed in early January and therefore has limited safety data availability. 2. CureDuchenne – What is Duchenne? https://cureduchenne.org/about/what-is-Duchenne/. 3. MedlinePlus – Duchenne and Becker muscular dystrophy: https://medlineplus.gov/genetics/condition/duchenne-and-becker-muscular-dystrophy/#frequency. SGT-003 – Differentiated Profile With Significant Potential • Compelling levels of microdystrophin expression observed (Mean 58%, N=10, September 29, 2025, cutoff) • Concordant restoration of DAPC & comprehensive improvements across muscle injury biomarkers suggest coordinated downstream effect (N=10-14, September 29, 2025, cutoff) • Early data suggests potential cardiac benefit through observed troponin I reductions & improvements in systolic function as measured by LVEF (N=14, September 29, 2025, cutoff) 7 Compelling Clinical Profile Demonstrated in Phase 1/2 INSPIRE DUCHENNE Trial • SGT-003 has been generally well tolerated in all (N=33) participants dosed as of January 9, 20261 • No drug-induced liver injury (DILI), thrombotic microangiopathy (TMA), atypical hemolytic uremic syndrome (aHUS) or myocarditis observed Safety and Tolerability Profile Continues to be Promising & Consistent • Majority of U.S. Duchenne prevalent population (~10-15k2 with ~5k aged 0-11) has not been treated with a gene therapy • U.S. incidence rate of at least 400 annual Duchenne births3 • EU population larger than U.S. population with no approved therapies available • FDA-approved gene therapy, ELEVIDYS®, priced $3M+ per dose in U.S. • Pricing and available U.S. & EU patient populations supports an estimated $20B+ total addressable market Potential Significant Commercial Opportunity • Multiple interactions with U.S. FDA expected throughout H1 2026 to align on Phase 3 confirmatory trial design and on necessary confirmatory evidence required to support potential accelerated approval Near-Term Catalysts
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© 2026 Solid Biosciences 8 nNOS=neuronal nitric oxide synthase; DILI=drug-induced liver injury; TMA=thrombotic microangiopathy; aHUS=atypical hemolytic uremic syndrome; DAPC=dystrophin-associated protein complex; GMP=good manufacturing practice. 1. Tidball JC and Wehling-Henricks, M. J Physiol. 2014;592(Pt 21):4627-4638. 2. Lai Y, et al. J Clin Invest. 2009;119(3):624-35. 3. Rodino -Klapac LR, et al. Hum Mol Genet. 2013;22(24):4929-37. 4. Froehner SC, et al. Hum Mol Genet. 2014;24(2):492-505. 5. Zhang YH, et al. J Physiol. 2014;592(Pt 15):3189-3200. 6. Ziolo MT, et al. J Mol Cell Cardiol. 2012;45(5):625-632. 7. Safety cutoff as of January 5, 2026, N=33. 8. Data as of September 29, 2025. SGT-003 Leverages Next-Generation Technology to Deliver Cutting Edge Duchenne Gene Therapy Actin Binding Domain R16/R17 Binding Domain (nNOS) COOH NH3 SGT-003 is the only Duchenne gene therapy to use a next-generation capsid (AAV-SLB101) Optimized Transgene Design Minimally Burdensome Immunomodulation Regimen Lower Viral Dose & High Level of Capsid Purity • Uniquely contains R16/R17 binding domain, which localizes nNOS to the muscle membrane • nNOS restoration may help improve muscle perfusion and performance, reduce pathology and increase cardiac protection1-6 • SGT-003 has been generally well-tolerated with no DILI, TMA, aHUS, myocarditis observed7 • Steroid-only prophylactic immunomodulatory regimen Extensive Early Analysis Demonstrated Compelling Biologic Profile • Interim data demonstrated compelling microdystrophin expression, reconstitution of key DAPC elements and improvement in a panel of muscle integrity biomarkers 8 • Lower viral dose (1.0E14 vg/kg) vs. FDA-approved Duchenne gene therapy (1.33E14 vg/kg) • ~75% full-to-empty capsid ratios at 1,000L GMP scaleAAV-SLB101
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© 2025 Solid Biosciences - Confidential 1. Announced as of January 13, 2026. Industry and Academic Interest in AAV-SLB101 Continues to Gain Momentum Quarter Over Quarter Agreements, including licenses, executed with corporations, institutions and academic labs for use of AAV-SLB101 1 9 1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950+ At Solid, we believe that delivery is the foundation of gene therapy – and that improving delivery technologies will make gene therapies safer, more effective and more accessible for all Contact our business development team to partner with us: businessdevelopment@solidbio.com - Expert U.S. Duchenne Clinician “AAV-SLB101 Will Be the Workhorse for AAV Gene Therapy for Years to Come”
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© 2026 Solid Biosciences Rapid transduction and transgene expression observed in preclinical models Improved skeletal & cardiac muscle tropism with reduced off-target effects observed in preclinical models AAV-SLB101 was rationally engineered to include an RGD motif with high-affinity binding to integrin receptors that improve cardiac & skeletal muscle cell uptake and reduce liver biodistribution Improved product purity, yields and COGS Designed with intention to reduce liver biodistribution AAV-SLB101 is a Next-Generation Capsid That has Demonstrated Rapid Transduction, Expression and Encouraging Safety Data Data on file. Solid Biosciences.
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© 2026 Solid Biosciences Highly improved target tissue expression achieved with AAV-SLB101 at low dose vs AAV9 or AAVrh74 11 IVIS=in vivo imaging system AAV-SLB101 has Demonstrated Rapid and Robust Transduction and Enhanced Expression Compared to First-Generation Capsids Luciferase Activity Measured by Whole Body IVIS 0 2 6 Total Flux (p/s) 4 Days Vehicle AAV9 AAVrh74 AAV-SLB101 1.2×10 10 1×1010 8×109 6×109 4×109 3×109 2×109 1×109 6×108 4×108 2×108 0 8 0 5 10 15 20 25 30 Days 6×109 4×109 2×109 0 Total Flux (p/s) ** **** **** **** *** 8×109 1×1010 Formulation Buffer AAV9 AAVrh74 AAV-SLB101 2E12 vg/kg5E13 vg/kg Luciferase Activity in Isolated Tissues 2.0E12 vg/kg (n=5 per tissue/capsid) Fold Change Luciferase Activity HEART 0 100 200 300 400 0 500 1000 1500 Fold Change Luciferase Activity QUADRICEPS Rapid transduction with expression via AAV-SLB101 observed as early as 2 days post-dose, remaining significantly higher than AAV9 or AAVrh74
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© 2026 Solid Biosciences Decreased Liver Biodistribution in Mice1 12 P-values: ***p<0.001; ****p<0.0001. NHP=Non-human primate; ALT=alanine transaminase; AST=aspartate aminotransferase; GGT=gamma-glutamyl transferase. 1. Data on file. Solid Biosciences. 2. Data cutoff of September 29, 2025. Values are means ± standard error of the mean. Compelling AAV-SLB101 Preclinical Liver Detargeting Data Reflected in Phase 1/2 INSPIRE DUCHENNE Trial As of January 9, 2026, 33 participants have been dosed with no drug-induced liver injury observed 0 250 500 750 Mean, U/L 0 250 500 750 Mean, U/L Liver Biomarkers – INSPIRE DUCHENNE Trial2 n=14 Mean, U/L0 15 30 -10 0 10 20 30 40 50 60 70 80 90 Days ALT After dosingBefore dosing Stable GGT Levels at Multiple Dose Levels of AAV-SLB101 in NHPs Through Day 901 GGT AST 0.0 1.0 2.0 3.0 **** *** vg/µg DNA Dose (vg/kg) 1E12 1E13 1E14 1.5×106 1×106 5×105 0 AAV-SLB101 AAV9 0 1 2 3 0 50 100 Fold Compared to Vehicle Day Relative to Dosing 0 vg/kg 1E14 vg/kg 3E14 vg/kg
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© 2026 Solid Biosciences 13 WB=western blot; MS=mass spectrometry; IF=immunofluorescence; nNOS=neuronal nitric oxide synthase; eMHC=embryonic myosin heavy chain; CK=creatine kinase; ALT=alanine transaminase; AST=aspartate aminotransferase; LDH=lactate dehydrogenase; SoC=standard-of-care. Data as of September 29, 2025. Solid Biosciences. Thorough Analysis of Skeletal & Cardiac Muscle Biomarkers Suggests Beneficial Biological Treatment Effect & Improved Muscle Integrity Microdystrophin (IF) β-sarcoglycan nNOS eMHC CK ALT AST LDH Titin 51% positive fibers (N=10) BIOMARKER IMPROVEMENT AT DAY 90 (MEAN) Troponin 50% positive fibers (N=10) 26% positive fibers (N=10) 49% reduction (N=10) 34% reduction (N=14) 41% reduction (N=14) 25% reduction (N=14) 42% reduction (N=12) 22% reduction (N=11) 31% reduction (N=14) Comprehensive improvements across 12 biomarkers contribute to desired target product profile (TPP) DAY 30 DAY 90DAY 0 High-Dose Steroids (SoC + Additional) SoC Steroids Only Biomarker Assessment Minimally burdensome prophylactic regimen supported by rigorous safety monitoring Microdystrophin (WB) 58% expression (N=10) Microdystrophin (MS) 58% expression (N=10) DAPC Markers Muscle Integrity Markers Cardiac Marker
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© 2026 Solid Biosciences Microdystrophin Transduction 1. Data cutoff of September 29, 2025. Solid Biosciences. Baseline Western Blot and Mass Spectrometry were both 0% mean normal dystrophin. Baseline mean dystrophin positive fibers were 1.5% measured by IF. Dystrophin positive fibers are not adjusted for fat and fibrosis; these are absolute numbers. 2. Representative images are shown. Microdystrophin Transduction and Expression Observed at Days 90 & 360 Post SGT-003 Treatment Comprehensive orthogonal measurements showed consistent microdystrophin expression across three measures Example Microdystrophin Biopsy2 Baseline Day 90 Mean SGT-003 Microdystrophin Expression1 Microdystrophin protein, Mean % 0 40 80 120 160 Western Blot Mass Spectrometry Immunofluorescence Day 90 Day 360 n=2n=10 n=2n=10 n=2n=10 107% 100% 67%58% 58% 51% DOSE VECTOR COPIES/NUCLEUS DAY 90 (N=10) VECTOR COPIES/NUCLEUS DAY 360 (N=2) 1.0E14 vg/kg 13 12 14
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© 2026 Solid Biosciences β-SG= β-sarcoglycan. Data cutoff of September 29, 2025. Solid Biosciences. β-SG was measured by immunofluorescence and nNOS was measured using an activity assay. Representative images from the same participant are shown. Microdystrophin Positive Fibers With Concordant DAPC Restoration Observed After SGT-003 Treatment β-SARCOGLYCAN POSITIVE FIBERS MICRODYSTROPHIN POSITIVE FIBERS BaselineDay 90 nNOS ACTIVITY MICRODYSTROPHIN + β-SARCOGLYCAN 26% 36% 0 20 40 60 Day 90 Day 360 nNOS, Mean % SGT-003 % Positive Fibers nNOS Activity 50% 70% 0 25 50 75 100 Day 90 Day 360 β-SG, Mean % SGT-003 % β-sarcoglycan Positive Fibers n=10 n=2 n=10 n=2 SGT-003 microdystrophin positive fibers (%) achieved a statistical correlation with both β-sarcoglycan positive fibers (%) and nNOS activity positive fibers (%) (r Pearson =0.95) 15
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© 2026 Solid Biosciences Data cutoff of September 29, 2025. Solid Biosciences. Representative images from the same participant are shown. 1. Dubuisson N, et al. Int J Mol Sci. 2022;23(24):16080. 2. Cardone N, et al. Acta Neuropathol Commun. 2023;11(1):167. Full Slide Scans of Muscle Biopsy Sections Showed Uniform Improvements in eMHC1,2 Muscle stem cells (satellite cells) are activated to repair & replace damaged muscle fibers–during this process, newly formed, dystrophic muscle fibers transiently express embryonic myosin heavy chain (eMHC)1,2 eMHC, Mean % -49%-60 -40 -20 0 Day 90 SGT-003 % eMHC Positive Fibers % positive microdystrophin fibers & the reduction in eMHC positive fibers at Day 90 were negatively correlated (r Pearson = -0.51) eMHC POSITIVE FIBERS MICRODYSTROPHIN POSITIVE FIBERS MICRODYSTROPHIN + eMHC BaselineDay 90 n=10 A treatment-mediated decrease in eMHC is favorable and may suggest muscle preservation 16
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© 2026 Solid Biosciences aTitin was batch analyzed at an earlier data cutoff date. bTwo LDH samples hemolyzed at day 90 and are not available for inclusion. Data cutoff of September 29, 2025. Solid Biosciences. Improved Measures of Muscle Integrity and Resilience Were Observed After SGT-003 Treatment Comprehensive and thorough assessment of muscle injury and metabolism Mean % Change from Baseline SERUM ALT % Change From Baseline -45 -30 -15 0 BL Day 90 Day 360 34% at Day 90 42% at Day 360 SERUM AST % Change From Baseline -45 -30 -15 0 BL Day 90 Day 360 Mean % Change from Baseline 25% at Day 90 40% at Day 360 SERUM Titin % Change From Baselinea -30 -15 0 BL Day 90 Day 360 Mean % Change from Baseline 22% at Day 90 25% at Day 360 SERUM LDH % Change From Baselineb -60 -40 -20 0 BL Day 90 Day 360 Mean % Change from Baseline 42% at Day 90 46% at Day 360 N=14 N=14 N=3 N=14 N=14 N=3 N=11 N=11 N=2 N=14 N=12 N=3 Mean % Change from Baseline SERUM CK % Change From Baseline -45 -30 -15 0 BL Day 90 Day 360 N=14 N=14 N=3 41% at Day 90 29% at Day 360 17
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© 2026 Solid Biosciences 1. Sheybani A, et al. Pediatr Res. 2022;92(6):1613-1620. 2. Data cutoff of September 29, 2025. Solid Biosciences. Troponin Reductions May Indicate Early Signals of SGT-003 Cardiac Treatment Effect Troponin I is released during myocardial cell injury, acting as a signal of muscle breakdown and a surrogate for cardiac myocyte damage1 Troponin, Mean % Change -120 -80 -40 0 40 80 BL Day 90 Day 360 N=14 N=14 N=3 31% 70% 18 INSPIRE DUCHENNE Percent Change From Baseline Troponin2
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© 2026 Solid Biosciences BL=baseline; CFB=change from baseline. 1. Data cutoff of September 29, 2025. Solid Biosciences. 2. The mean ± SD normal LVEF range is 60% to 69% for this age-matched population. 3. Romanowicz J, et al. J Am Soc Echocardiogr. 2023;36(3):310-323. Stable-to-Improved Cardiac Function Observed After SGT-003 Dosing Early observations of improved cardiac function driven by participants with low to low-normal baseline left ventricular ejection fraction (LVEF)1 0 6 12 18 BL 90 180 360 Mean Absolute Change From Baseline LVEF, % INSPIRE DUCHENNE Absolute Change From Baseline LVEF (%) N=5 N=5 N=3 N=2 Visit Day Low to Low-Normal Baseline LVEF Participants (n=5 at baseline) 63 60 56 66 66 69 64 64 66 45 55 65 75 85 Participants who reached Day 90 Participants who reached Day 180 Participants who reached Day 360 Mean Absolute LVEF, % INSPIRE DUCHENNE Absolute LVEF Over Time (%) Visit Day N=14 N=8 N=2 Day 90 Day 180 Day 360 BL Day 90 Day 180 BL Day 90 BL 60-69% Normal Range of LVEF = Mean ± SD2,3 (n=14 at baseline) 19
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© 2026 Solid Biosciences 20 CTCAE, common terminology criteria for adverse events. 1. The 33rd participant was dosed in early January and therefore has limited safety data available. INSPIRE DUCHENNE Interim Safety Summary for All Participants 33 participants have received SGT-003 (1.0E14 vg/kg) at ages ranging from 1 to 10 years as of January 9, 2026 SGT-003 TREATMENT-RELATED ADVERSE EVENTS as of January 9, 2026 (N=33)1 N (%) Serious Adverse Events (SAEs) 1 (3.0)2 Most Common Treatment-related Adverse Events (AEs) Vomiting 22 (66.7) Nausea 21 (63.6) Thrombocytopenia / Platelet Count Decreased 14 (42.4) Decreased Appetite 11 (33.3) Headache 6 (18.2) COHORTS ELIGIBLE AGE RANGE (YEARS) AGE AT ENROLLMENT (YEARS) WEIGHT FOR DOSING (KG) PARTICIPANTS ENROLLED (N) 1-3 0 to <12 1 to 10 9.9 to 39.7 33 Based upon compelling safety & tolerability profile, SGT-003 is now being administered in an outpatient setting 2. One (n=1) CTCAE Grade 3 serious adverse event of immune-mediated myositis. The myositis was not associated with muscle pain or weakness. The participant responded promptly to steroid treatment, with all clinical symptoms noted at presentation resolving and with CK levels declining well below baseline.
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© 2026 Solid Biosciences Acceleration of Participant Dosing Reflects Participant Demand 7 participants dosed Aug. 2025 Nov. 2025 Jan. 2026 Feb. 2025 Participant enrollment rate in the INSPIRE DUCHENNE trial has repeatedly outpaced prior guidance, suggesting strong Duchenne community appetite for new therapies 21 15 participants dosed 33 participants dosed 23 participants dosed
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© 2026 Solid Biosciences 2026: Integrated U.S. & Ex-U.S. Pivotal Trial Strategy Underway to Support Potential Accelerated Regulatory Authorizations Novel therapeutic design, rapid participant enrollment, favorable tolerability profile and robust biomarker data continue to build position of strength for SGT-003 both in the U.S. and ex-U.S. Phase 1/2 open-label, non-randomized clinical trial designed to support potential accelerated approval in the U.S. STATUS: Active & enrolling ambulatory boys aged 0 to < 12; N=33 dosed as of January 9, 2026 PRIMARY ENDPOINT: Change from baseline in microdystrophin protein levels; incidence of TEAEs TRIAL SITES: 15 sites activated across U.S., Canada, U.K. & Italy Phase 3 randomized, double-blind, placebo-controlled clinical trial designed to support ex-U.S. regulatory authorizations STATUS: Active & enrolling ambulatory boys aged 7 to 11 PRIMARY ENDPOINT: Change from baseline in Time to Rise (TTR) from supine at Day 540 (18 months) TRIAL SITES: 2 sites activated in Canada and Australia with planned expansion into additional countries, including in Europe, beginning in mid-year 2026, subject to regulatory approvals 22
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© 2026 Solid Biosciences Participant enrollment in Phase 3 IMPACT DUCHENNE ongoing U.K. Innovation Passport (ILAP) granted; SGT-003 has potential to be U.K. ’s first- to-market Duchenne gene therapy Potential accelerated approval pathway 1 Ex-U.S., Phase 3, placebo-controlled confirmatory trial design (IMPACT DUCHENNE)1 Confirmatory evidence required to support accelerated approval1 Q4 2025 2026 Q1 2026 Q1/Q2 2026 Mid-Year 2026 1. Expected timing, subject to scheduling. 2026: Integrated U.S. & Ex-U.S. Pivotal Trial Strategy Underway to Support Potential Accelerated Regulatory Authorizations (cont.) ILAP designation provides enhanced and early interactions with the U.K. MHRA, NHS, and HTA bodies with the aim to expedite approval and time to reimbursement for new drugs; through the ILAP program, Solid intends to pursue a conditional regulatory pathway that may enable approval years earlier than traditional pathways U.S. EX-U.S. 23 Dec 2025 First participant enrolled in Phase 3 IMPACT DUCHENNE trial Anticipated meetings with FDA to align on:
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© 2026 Solid Biosciences ~10,200 ~(1,100) ~(600) ~8,500 ~850 24 Total Patients with Duchenne (Ages 0 – 11) Patients Treated with ELEVIDYS (As of 3Q25)2 Patients Treated with ELEVIDYS (4Q25 – 4Q27)3 Patients to be Treated (Ages 0 – 11) Annual Duchenne Incidence US and EU Duchenne Patients (Ages 0 – 11) 1 3 US ~4,800 ~400 US Vast majority of treatment-eligible Duchenne patients remain undosed, with current revenue trajectory well below incident population Potential opportunities: • Currently eligible, but untreated • Younger patients (< 4 years) becoming eligible • Annual Duchenne incidence • Ex-US patients ~$25B Potential Market Opportunity – Available Ambulatory ~$3B+ = ~$28B+ Patients to be Treated Annual Incidence Market Opportunity Potential to expand further to APAC and non-ambulatory patients Assuming a net price of $3M per patient4 Duchenne Remains a Mega-Blockbuster Commercial Opportunity 1. Estimates based on annual birth rates in the EU, assuming 50% male births, and a Duchenne prevalence rate of 1 in every 3,500-5,000 male births, and annual incidence rate of 400 Duchenne births in the US, in the 0 through 12 year population. 2. Sarepta Therapeutics’ filings and website; includes global clinical and commercial patients treated with ELEVIDYS. 3. Wall Street Research, data as of December 2025: estimated ~600 US patients will be treated with ELEVIDYS between 4Q25 and 4Q27 based on broker sales projections of ~50–70 patients / quarter and assumes no patients in EU as ELEVIDYS is not approved. 4. Estimate only, actual pricing not yet determined and is subject to applicable regulatory approval on pricing. 2 ~450 EU EU ~5,400
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© 2026 Solid Biosciences Investigational Friedreich’s Ataxia (FA) Gene Therapy SGT-212
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© 2026 Solid Biosciences SGT-212 Leverages Precision Technology to Address Quality of Life and Cardiac Mortality IDN=intradentate nuclei; IV=intravenous 1. Friedreich’s Ataxia Research Alliance (FARA) Voice of the Patient Survey, 2017. SGT-212 is the only dual route gene therapy (IDN & IV) approach for the treatment of Friedreich’s ataxia – designed to address the neurologic, systemic and cardiac manifestations of the disease Slowing or halting disease progression is the most meaningful treatment impact for the FA community1 Treatment approaches that address both quality of life and mortality/lifespan represent the future standard for FA disease management SGT-212: • Capsid: AAVhu68 • Dosing Cadence: IDN first, followed by IV • Ubiquitous promoter 26
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© 2026 Solid Biosciences 27 Intra-procedural MRI-imaging confirmed precise delivery of SGT-212 into the dentate nuclei SGT-212: First Participant Dosed in Phase 1b FALCON Trial Dentate nuclei (DN) Front Fixation Device SGT-212 Front Post-Treatment With SGT-212Baseline MRI Pre-Treatment With SGT-212 Fixation Device Front Dentate nuclei (DN)
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© 2026 Solid Biosciences 28 A first-in-human, open-label, multi-center trial designed to evaluate the safety and tolerability of contemporaneous IDN and systemic IV infusion of SGT-212 gene therapy in participants with FA Non-ambulatory1 Ambulatory2 Ambulatory & Non- Ambulatory (Optional)3 Cohorts Study Endpoints Primary Endpoint Incidence and severity of TEAEs from baseline to month 12 Secondary & Exploratory Endpoints Change from baseline in serum biomarkers Change from baseline cardiac frataxin expression at Day 90 and Month 18 Change from baseline in assessments measuring key aspects of the disease, such as neuromuscular function, fatigue and speech Change from baseline cardiac structure and function Study to enroll approximately 10 participants aged 18-40 years with FA and documented cardiac hypertrophy • Multiple inquiries received from interested FA community members located both in and ex-U.S. • Solid has collaborated with experts from 5 leading institutions to develop, test and refine the stereotactic, MRI-guided neurosurgical IDN- dosing procedure used in FALCON Community Interest FALCON Phase 1b Trial Design
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© 2026 Solid Biosciences 29 Poised for Transformational Value Inflection in 2026 & Beyond Major milestones anticipated across all lead programs create multiple opportunities for value inflection Capsid Library Continued AAV-SLB101 out licensing & creation of proprietary next-generation capsid libraries SGT-003 Duchenne Update on potential alignment with FDA on accelerated approval pathway1; additional data from INSPIRE DUCHENNE SGT-212 FA Initial data from Phase 1b FALCON trial2 SGT-501 CPVT Initial safety data from Phase 1b ARTEMIS trial2 1. Expected timing, subject to scheduling and formal receipt of meeting minutes. 2. Subject to participant enrollment Mid-2026 H2 2026 H2 2026 Throughout 2026
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© 2025 Solid Biosciences - Confidential 500 Rutherford Avenue, Third Floor, Charlestown, MA 02129 investors@solidbio.com www.solidbio.com Learn about ways to partner with us: www.solidbio.com/partners/