Today, Gemma Biotherapeutics (GEMMABio), a clinical‑stage, global, genetic therapeutics company, shared information about the company’s Duchenne muscular dystrophy program, presenting preclinical data supporting candidate declaration for GB703, a novel, investigational gene therapy for the treatment of Duchenne.
GB703 utilizes a de-immunized, miniature transgene – a hybrid micro-utrophin/dystrophin that incorporates the self-utrophin-derived exon 8-11 region – that is intended to potentially expand patient eligibility to include those with deletions in the early regions of the dystrophin gene (N-terminal) that have been previously excluded from approved and investigational products due to safety concerns. The investigational gene therapy also deploys a novel myotropic (muscle targeted) capsid design, which GEMMABio believes may improve delivery at low doses. According to GEMMABio, the hybrid micro-utrophin/dystrophin payload showed measurable biological effects in an early stage mouse model, which provides early evidence that the newly produced chimeric protein can perform some of the biological functions of a dystrophin protein.
According to GEMMABio, the company is continuing to execute on Investigational New Drug (IND)-enabling studies to bring GB703 to the clinic as swiftly as possible.
PPMD is excited to see a new potential gene therapy candidate in early development that may offer solutions to current challenges and we welcome GEMMABio to the Duchenne community. We look forward to working with GEMMABio and will share further updates on the development of GB703 as information becomes available.
Read GEMMABio’s press release here. Read GEMMABio’s community letter below:
To the DMD Patient Community:
We would like to introduce ourselves and our commitment to the Duchenne Muscular Dystrophy (DMD) community. Today, May 14th, 2026, GEMMA Biotherapeutics (GEMMABio) announced preclinical data supporting the continued development of GB703, a novel candidate for a potential, investigational gene therapy to treat DMD at the 2026 American Society of Gene and Cell Therapy (ASGCT) conference in Boston, MA.
The official press release can be found here.
In 2024, GEMMABio, under the leadership of Jim Wilson, MD, PhD, spun out from the University of Pennsylvania, where Dr. Wilson previously ran the first and largest academic-based gene therapy program (“Penn GTP”), as well as a research-based and patient-facing organization, the Orphan Disease Center. Dr. Wilson has a nearly 40-year history in rare disease research and gene therapy—his lab discovered a family of novel adeno-associated viruses (AAV) and to date, his team’s accomplishments include 3 FDA-approved AAV-based gene therapies, several active programs currently in development, 95 patents on gene therapy-related technologies, and first-in-patient studies in 17 different diseases.
Dr. Wilson’s tenure at Penn contributed to transformational advancements in preclinical research for rare diseases and in the field of gene therapy. Building on this foundation, he started GEMMABio to help bring these promising clinical opportunities closer to patients. GEMMABio is a clinical-stage, global genetic medicines company based in Philadelphia, PA. We have approximately 65 full-time employees, most of whom transferred directly from Penn GTP and brought their extensive expertise to our new startup company. GEMMABio provides the infrastructure and resources to support research & development, clinical trials, commercialization, and global access for communities with significant unmet need, including those living with DMD.
Over the years, Dr. Wilson and his team have provided advice to the DMD community including Parent Project Muscular Dystrophy (PPMD), Muscular Dystrophy Association (MDA), and French Muscular Dystrophy Association (AFM-Téléthon). Recently, Dr. Wilson’s research team developed a novel AAV with enhanced delivery to heart and muscle, as well as an engineered, hybrid micro-utro/dystrophin therapeutic payload to evade immune responses. GEMMABio scientists have been working steadily on this original DMD program since we launched the startup company in 2024. Today, DMD was declared a named, core program for GEMMABio.
Dr. Wilson and his expert team of research scientists led by our Chief Scientific Officer, Juliette Hordeaux, DVM, PhD, DECVP, are seeking to overcome some of the prominent challenges the DMD community has faced with the existing approved and investigational gene therapies. Dr. Hordeaux, who has worked in the rare disease space for 15+ years, presented an overview of GEMMA’s preclinical research at the ASGCT conference that included the following key points:
- GB703 is designed to potentially broaden the spectrum of dystrophin mutations that may be treated
- GB703 deploys a novel myotropic capsid designed to optimize delivery at lower doses
- GB703 showed measurable biological effects in a mouse model of DMD
We recognize the significant unmet needs within the DMD community, particularly related to trial eligibility and preservation of lung and heart function. Our goal is to address these challenges while maintaining patient safety as our highest priority. We remain focused on evaluating the safety and efficacy of this potential investigational therapy as we work to advance into the clinic as soon as possible.
We look forward to providing additional updates in the future.
Regards,
Monique Molloy, Chief Corporate Affairs Officer
Samantha Charleston, Sr. Director, Patient Advocacy & Corporate Affairs
The post GEMMABio Announces Duchenne Muscular Dystrophy Program, Shares Preclinical Data for Investigational Gene Therapy for Duchenne appeared first on Parent Project Muscular Dystrophy.