Genethon, a unique non-profit gene therapy R&D organization founded by the French Muscular Dystrophy Association (AFM-Telethon), today announced The Lancet Neurology published online preliminary results of a clinical trial conducted by Astellas Pharma using a gene therapy developed by Genethon for X-linked myotubular myopathy, a rare genetic muscle disease affecting 1 in 50,000 newborn boys.
Myotubular myopathy is caused by mutations in the MTM1 gene encoding myotubularin, a protein involved in muscle cell function. Characterized by extreme muscle weakness and severe respiratory distress, 50% of affected children die before age 18 months and 75% die before age 10. The gene therapy uses an adeno-associated viral vector (AAV8) to deliver a copy of the MTM1 gene.
Of 24 children enrolled in the ASPIRO trial, conducted in France, Germany, Canada and the U.S., 16 of them can now breathe without assistance, 12 stand up on their own, and 8 can walk. The trial has been paused for an investigation into the origins of the complications responsible for the deaths of 4 children, who showed signs of pre-exiting hepatobiliary pathology.
“These clinical results show both how spectacularly effective gene therapy can be, and the challenges that remain, particularly in terms of side effects in certain contexts,” said Frederic Revah, Genethon CEO. “While our teams are already committed to understanding and anticipating these issues, the knowledge gained from this clinical trial, which highlights certain limitations and particular hepatic susceptibilities, is rich in lessons for the entire scientific community.”
Ana Buj-Bello, Director of Research at Inserm and head of Genethon’s Neuromuscular Diseases and Gene Therapy team, designed the gene therapy. She is one of the authors on The Lancet Neurology article and co-authored the preclinical work that led to the ASPIRO trial.
