Limb‑Girdle Muscular Dystrophy: First Three Children Treated with ATA‑200 Gene Therapy in on-going LGMD‑R5 Clinical Trial, and extension of Partnership with The Dion Foundation

Atamyo Therapeutics, a clinical-stage biotechnology company, spun of Genethon, focused on the development of new generation gene therapies targeting muscular dystrophies and cardiomyopathies, announced that the first three patients have been treated with its ATA‑200 gene therapy in a phase 1b/2 clinical trial for LGMD‑R5 (LGMD2C), a severe form of limb‑girdle muscular dystrophy caused by γ‑sarcoglycan (SGCG) deficiency. This rare disease typically begins in early childhood and leads to progressive muscle weakness, often resulting in loss of ambulation before adulthood.

The phase 1b/2 trial (NCT05973630) is a open-label dose escalation study, and evaluates safety, pharmacodynamics, efficacy and immunogenicity of ATA‑200, delivered as a single intravenous infusion. This study is being conducted at the Powell Gene Therapy Center, University of Florida, by Dr. Barry Byrne.

ATA‑200 is an adeno‑associated virus (AAV)‑based gene therapy carrying a functional copy of the human SGCG gene, enabling the production of γ‑sarcoglycan — a protein essential for maintaining muscle fiber integrity.

Additional results from this ongoing study are expected to be published in the coming months.

“We have been delighted to work with Atamyo and the Dion Foundation in the design and conduct of the ATA-200 study.” said Dr. Barry Byrne, Associate Chair of Pediatrics and Director of the Powell Gene Therapy Center, University of Florida, in Gainesville, Florida, where the first three patients were dosed, and principal investigator of this trial. “We look forward to continuing assessing the potential benefit of ATA-200 in the first children to receive the product.”

This gene therapy is based on the research led by Isabelle Richard, Ph.D., Research Director at the French National Centre for Scientific Research (CNRS) and Head of the Progressive Muscular Dystrophies Laboratory at Généthon.

This milestone illustrates the strength of our programs in advancing gene therapy from fundamental research to clinical proof‑of‑concept, in close collaboration with academic teams and patient‑focused organizations committed to rare neuromuscular diseases.

For more information: read the press release on Atamyo website