Limb-Girdle Muscular Dystrophy, Type 2C

– U.S. FDA has confirmed that screening and dosing may proceed in Study SRP-9005-101 for LGMD2C/R5 – Enrollment and dosing completed in Study SRP-9004-102 for LGMD2D/R3 – Data expected for SRP-9003 for LGMD2E/R4 by mid-2025 CAMBRIDGE, Mass.--(BUSINESS WIRE)--Apr. 15, 2025-- Sarepta Therapeutics, Inc. (NASDAQ:SRPT), the leader in precision genetic medicine for rare diseases, today shared updates from its clinical programs focused on limb-girdle muscular dystrophy (LGMD) subtypes 2C/R5, 2D/R3, and 2E/R4. SRP-9005 for LGMD type 2C/R5: Following input from the U.S. Food and Drug Administration (FDA), Office of Therapeutic Products (OTP), Sarepta is cleared to proceed with dosing in Study SRP-9005-101 (COMPASS) in the U.S. COMPASS is a first-in-human clinical study of SRP-9005, an investigational gene therapy for LGMD type 2C/R5, or gamma-sarcoglycanopathy. SRP-9004 for LGMD type 2D/R3: Enrollment and dosing is complete in Study SRP-9004-102 (DISCOVERY). DISCOVERY is a phase 1, proof-of-concept study evaluating safety and expression of the alpha-sarcoglycan protein after treatment with SRP-9004, an investigational gene therapy for the treatment of LGMD type 2D/R3, or alpha-sarcoglycanopathy. SRP-9003 for LGMD type 2E/R4: Enrollment and dosing is complete in Study SRP-9003-301 (EMERGENE). EMERGENE is a phase 3 clinical trial of SRP-9003 (bidridistrogene xeboparvovec) for the treatment of LGMD type 2E/R4, or beta-sarcoglycanopathy. EMERGENE is a global study and the primary endpoint is the biomarker expression of beta-sarcoglycan protein. A pre-Biologics License Application (BLA) meeting has occurred and the OTP has confirmed eligibility for the accelerated approval pathway for the program. Sarepta remains on track to submit a BLA to the U.S. FDA in the second half of 2025. “There are no disease-modifying treatments approved for patients with any subtype of limb-girdle muscular dystrophy, and the unmet medical need is significant. Following feedback from U.S. FDA, we are pleased to announce that screening can proceed in Sarepta’s first clinical study for a gene therapy for individuals with LGMD type 2C – the fourth LGMD program that Sarepta has advanced into the clinic,” said Louise Rodino-Klapac, Ph.D., executive vice president, chief scientific officer and head of research and development, Sarepta Therapeutics. “In addition to our progress with SRP-9004 and SRP-9005, we remain on track to share data in the first half of this year from the EMERGENE study with SRP-9003. Our confidence in the potential for gene therapy to bring meaningful treatments to patients with rare, genetic based diseases remains high and the rapid progress across our LGMD pipeline is encouraging.” About Limb-Girdle Muscular Dystrophy Limb-girdle muscular dystrophies (LGMD) are genetic diseases that cause progressive, debilitating weakness and wasting that begins in muscles around the hips and shoulders before progressing to muscles in the arms and legs. There are more than 30 distinct subtypes of LGMD, each with a unique genetic mutation and distinct symptoms, progression, and treatment approaches. Sarepta’s leading LGMD pipeline currently has gene therapy programs in different stages of development for LGMD 2B/R2, LGMD 2E/R4, LGMD 2D/R3, LGMD 2C/R5, and LGMD 2A/R1 which together represent more than 70 percent of known LGMD cases. Sarepta is also the sponsor of JOURNEY, a natural history study evaluating disease progression for four LGMD subtypes: 2C/R5, 2D/R3, 2E/R4 and 2A/R1. JOURNEY is actively enrolling globally. About SRP-9003 (bidridistrogene xeboparvovec) SRP-9003 (bidridistrogene xeboparvovec) is an investigational gene therapy that uses the AAVrh74 vector, which is designed to be systemically and robustly delivered to skeletal, diaphragm and cardiac muscle, making it an ideal candidate to treat neuromuscular diseases. SRP-9003 is intended to deliver a full-length beta-sarcoglycan transgene and uses the MHCK7 promoter, chosen for its ability to robustly express in the heart1,2,3 which is critically important for patients with limb-girdle muscular dystrophy Type 2E (LGMD2E), also known as beta-sarcoglycanopathy and LGMDR4, many of whom die from pulmonary or cardiac complications. About SRP-9004 (patidistrogene bexoparvovec) SRP-9004 (patidistrogene bexoparvovec) is an investigational gene therapy for limb-girdle muscular dystrophy Type 2D (LGMD2D/R3). LGMD2D/R3 causes muscle weakness and primarily affects the muscles around the hips, shoulders, and thighs. SRP-9004 is engineered using the AAVrh74 vector, which is designed to be systemically and robustly delivered to skeletal, diaphragm and cardiac muscle, making it an ideal candidate to treat neuromuscular diseases. Intended to deliver a full-length alpha-sarcoglycan transgene, SRP-9004 uses the tMCK promoter, chosen for its ability to selectively express in skeletal muscle which is critically important for patients with LGMD2D/R3. About SRP-9005 SRP-9005 is an investigational gene therapy for patients with limb-girdle muscular dystrophy Type 2C (LGMD2C/R5), also known as gamma-sarcoglycanopathy. SRP-9005 is intended to deliver a full-length gamma-sarcoglycan transgene using the AAVrh74 vector. SRP-9005 uses the MHCK7 promoter, chosen for its ability to robustly express in the heart, which is critically important for those with LGMD2C, many of whom die from pulmonary or cardiac complications. About Sarepta Therapeutics Sarepta is on an urgent mission: engineer precision genetic medicine for rare diseases that devastate lives and cut futures short. We hold leadership positions in Duchenne muscular dystrophy (Duchenne) and limb-girdle muscular dystrophies (LGMDs) and are building a robust portfolio of programs across muscle, central nervous system, and cardiac diseases. For more information, please visit www.sarepta.com or follow us on LinkedIn, X, Instagram and Facebook. Internet Posting of Information We routinely post information that may be important to investors in the 'For Investors' section of our website at www.sarepta.com. We encourage investors and potential investors to consult our website regularly for important information about us. Forward-Looking Statements In order to provide Sarepta’s investors with an understanding of its current results and future prospects, this press release contains statements that are forward-looking. Any statements contained in this press release that are not statements of historical fact may be deemed to be forward-looking statements. Words such as “believes,” “anticipates,” “plans,” “expects,” “will,” “may,” “intends,” “prepares,” “looks,” “potential,” “possible” and similar expressions are intended to identify forward-looking statements. These forward-looking statements include statements relating to our future operations, business plans, market opportunities, priorities and research and development programs and technologies; the potential benefits of our technologies, scientific approaches and strategic partnerships; and expected milestones and plans, including beginning dosing in Study SRP-9005-101, sharing data from our EMERGENE study in the first half of the year, and our expectation to file a BLA for SRP-9003 in the second half of 2025. These forward-looking statements involve risks and uncertainties, many of which are beyond Sarepta’s control. Actual results could materially differ from those stated or implied by these forward-looking statements as a result of such risks and uncertainties. Known risk factors include the following: success in preclinical and clinical trials, especially if based on a small patient sample, does not ensure that later clinical trials will be successful, and the results of future research may not be consistent with past positive results or may fail to meet regulatory approval requirements for the safety and efficacy of product candidates; the expected benefits and opportunities related to our agreements with strategic partners may not be realized or may take longer to realize than expected due to a variety of reasons, including any inability of the parties to perform their commitments and obligations, challenges and uncertainties inherent in product research and development and manufacturing limitations; if the actual number of patients suffering from the diseases we aim to treat is smaller than estimated, our revenue and ability to achieve profitability may be adversely affected; we may not be able to execute on our business plans, including meeting our expected or planned regulatory milestones and timelines, research and clinical development plans, and bringing our product candidates to market, for various reasons, some of which may be outside of our control, including possible limitations of company financial and other resources, manufacturing limitations that may not be anticipated or resolved for in a timely manner, and regulatory, court or agency decisions, such as decisions by the United States Patent and Trademark Office with respect to patents that cover our product candidates; and those risks identified under the heading “Risk Factors” in our most recent Annual Report on Form 10-K for the year ended December 31, 2024 filed with the Securities and Exchange Commission (SEC) as well as other SEC filings made by the Company which you are encouraged to review. References View source version on businesswire.com: https://www.businesswire.com/news/home/20250415170851/en/ Investor Contact: Ian Estepan 617-274-4052 iestepan@sarepta.com Media Contacts: Tracy Sorrentino 617-301-8566 tsorrentino@sarepta.com Kristen Stancil 617-528-8183 kstancil@sarepta.com Source: Sarepta Therapeutics, Inc.

EVRY, France--( BUSINESS WIRE )-- Atamyo Therapeutics a clinical-stage biotechnology company focused on the development of new generation gene therapies targeting muscular dystrophies and cardiomyopathies, today announced that the U.S. Food & Drug Administration (FDA) has cleared its Investigational New Drug (IND) application for ATA-200 to proceed in a Phase 1b/2b clinical trial. ATA-200 is a one-time gene therapy for the treatment of γ-sarcoglycan related limb-girdle muscular dystrophy Type 2C/R5 (LGMD2C/R5), a serious and debilitating condition that affects children and leads to loss of ambulation before adulthood. The multicenter Phase1b open-label dose escalation study ( NCT05973630 ) will evaluate safety, pharmacodynamics, efficacy, and immunogenicity in children receiving intravenous ATA-200, a single-dose Adeno-Associated Virus (AAV) vector carrying the human γ-sarcoglycan transgene. The deployment in the US of Atamyo’s clinical trial of ATA-200 is funded by The Dion Foundation for Children with Rare Diseases . This study has already received regulatory clearance in France and Italy. “This IND clearance in an important step to bring ATA-200 to US children suffering from this highly debilitating LGMD-2C/R5 disease,” said Sophie Olivier, MD, Chief Medical Officer of Atamyo. “We are proud to be the first treatment for LGMD-2C/R5 to enter into clinical development in the US and we are committed to opening the first US center before year-end,” added Stéphane Degove, Atamyo’s Chief Executive Officer. In addition, Atamyo announced the US FDA has awarded Orphan Drug Designation for ATA-200. Orphan Drug Designations by the FDA grants seven years of market exclusivity in the US. This Orphan Drug Designation for ATA-200 was granted a few weeks after ATA-200 received Rare Pediatric Disease Designation by the FDA. LGMD-2C/R5 is a rare genetic disease caused by mutations in the gene that produces γ-sarcoglycan, a transmembrane protein that is involved in the connection between muscle fibers and their environment. It affects an estimated 2,000 people in Europe and in the US. In the classical form, symptoms appear in early childhood and patients suffer from progressive muscular weakness leading to loss of ambulation before adulthood. Cardiac involvement, typically presenting as dilated cardiomyopathy, is reported in approximately half of patients and will eventually impact life expectancy. There is no curative treatment. The management of LGMD-2C/R5 is solely supportive. ATA-200, the gene therapy for LGMD-2C/R5, delivers a normal copy of the gene for production of γ-sarcoglycan. In preclinical mice models, ATA-200 demonstrated its tolerability and capability to correct symptoms and biomarkers of the pathology. Atamyo plans to initiate enrolling patients for this clinical trial in the 4 th quarter of 2024. The therapy is based on the research of Atamyo Chief Scientific Officer Isabelle Richard, Ph.D., Research Director at CNRS who heads the Progressive Muscular Dystrophies Laboratory at Genethon. About Atamyo Therapeutics Atamyo Therapeutics is a clinical-stage biopharma focused on the development of a new generation of effective and safe gene therapies for neuromuscular diseases. A spin-off of gene therapy pioneer Genethon, Atamyo leverages unique expertise in AAV-based gene therapy and muscular dystrophies from the Progressive Muscular Dystrophies Laboratory at Genethon. Atamyo’s most advanced programs address different forms of limb-girdle muscular dystrophies (LGMD), with two clinical-stage programs targeting respectively LGMD-R9 and LGMD-R5. The name of the company is derived from two words: Celtic Atao which means “Always” or “Forever” and Myo which is the Greek root for muscle. Atamyo conveys the spirit of its commitment to improve the life of patients affected by neuromuscular diseases with life-long efficient treatments. For more information visit www.atamyo.com

Atamyo has received approval to initiate a clinical trial of ATA-200 gene therapy in France and Italy ATA-200 is a single-injection gene therapy aimed to treat LGMD2C/R5 caused by mutations in the γ-sarcoglycan gene The phase 1b, dose-escalation study will evaluate the safety and efficacy of ATA-200 in children EVRY, France--(BUSINESS WIRE)-- Atamyo Therapeutics, a clinical-stage biotechnology company focused on the development of new-generation gene therapies targeting muscular dystrophies and cardiomyopathies, today announced the first authorization of a Clinical Trial Application (CTA) in Europe for ATA-200, its gene therapy for the treatment of the γ-sarcoglycan related limb-girdle muscular dystrophy Type 2C/R5 (LGMD2C/R5). This authorization was first granted by the Italian Medicines Agency (AIFA), then by the French Medicines Agency (ANSM). “We are thrilled to obtain our CTA approval in France and Italy for the devastating LGMD2C/R5 disease affecting primarily a pediatric population and for which there is no approved treatment,” said Dr Sophie Olivier, Chief Medical Officer of Atamyo. “Atamyo plans to initiate dosing in patients for ATA-200 in third quarter 2024.” “LGMD 2C/R5 is a severe muscular dystrophy with an onset in early childhood and loss of ambulation generally occurring before adolescence,” said Pr. Giacomo Comi, Full Professor of Neurology at the University of Milan (Italy), and principal investigator of this trial. “It is a great motivation to know that the work we are doing has the potential to make a life-changing difference for the patients affected by this disease.” “This is a significant milestone for LGMD-2C/R5 patients and for Atamyo as ATA-200 is the first treatment targeting LGMD-2C/R5 to enter clinical trials,” said Stéphane Degove, CEO of Atamyo Therapeutics. “With the ongoing clinical trial of ATA-100 in LGMD2I/R9, the initiation of the clinical program for ATA-200 confirms our unique capabilities in bringing to patients suffering from limb-girdle muscular dystrophies a new generation of safe and effective gene therapies.” This clinical trial (NCT05973630) is a multicenter, Phase 1b, open-label, dose escalation study evaluating safety, pharmacodynamic, efficacy, and immunogenicity of intravenous ATA-200, a single-dose Adeno-Associated Virus (AAV) vector carrying the human γ-sarcoglycan transgene. LGMD2C/R5 is a rare genetic disease caused by mutations in the gene that produces γ-sarcoglycan, a transmembrane protein that is involved in the connection between muscle fibers and their environment. It affects an estimated 2,000 people in Europe. In the classical form, symptoms appear in early childhood and patients suffer from progressive muscular weakness leading to loss of ambulation before adulthood. Cardiac involvement, typically presenting as dilated cardiomyopathy is reported in approximately half of patients. There is no curative treatment. The management of LGMD2C/R5 is solely supportive. ATA-200, a gene therapy candidate for LGMD2C/R5, delivers a normal copy of the gene for production of γ-sarcoglycan protein. In preclinical models, a single systemic injection of ATA-200 demonstrated its tolerability and capability to correct symptoms and biomarkers of the pathology. ATA-200 has been granted Orphan Medicinal Product Designation by the European Medicines Agency (EMA). The therapy is based on the research of Atamyo Chief Scientific Officer Isabelle Richard, Ph.D., Research Director at National Center of Scientific Research (CNRS) in France and head of the Progressive Muscular Dystrophies Laboratory at Genethon. In addition to its LGMD2C/R5 gene therapy, Atamyo is developing a clinical trial with ATA-100 gene therapy for LGMD2I/R9, related to deficiencies in FKRP; and is in IND-enabling studies for LGMD2A/R1, related to deficiencies in calpain protein. About Atamyo Therapeutics Atamyo Therapeutics is a clinical-stage biopharma focused on the development of a new generation of effective and safe gene therapies for neuromuscular diseases. A spin-off of gene therapy pioneer Genethon, Atamyo leverages unique expertise in AAV-based gene therapy and muscular dystrophies from the Progressive Muscular Dystrophies Laboratory at Genethon. Atamyo’s most advanced programs address different forms of limb-girdle muscular dystrophies (LGMD), with two clinical-stage programs targeting respectively LGMD2I/R9 and LGMD2C/R5. The name of the company is derived from two words: Celtic Atao which means “Always” or “Forever” and Myo which is the Greek root for muscle. Atamyo conveys the spirit of its commitment to improve the life of patients affected by neuromuscular diseases with life-long efficient treatments. For more information visit . View source version on businesswire.com: Contacts U.S. Contact: Charles Craig, Opus Biotech Communications Charles.s.craig@gmail.com, 404-245-0591 European Contact: contact@atamyo.com Source: Atamyo Therapeutics View this news release online at: