NEW YORK – Genethon on Tuesday said that based on the positive opinion from a data monitoring committee, it is preparing to take an ongoing Phase I/II/III trial testing its Duchenne muscular dystrophy (DMD) gene therapy candidate into a pivotal stage in Europe.
Genethon made the announcement on the heels of an initial safety and pharmacodynamic data readout from the clinical trial of the gene therapy, GNT0004, at the Myology 2024 conference this week in Paris. So far, five DMD patients 6 to 10 years of age have been treated within the study, four in France and one in the UK.
DMD is a rare and progressive neuromuscular disease caused by mutations in the DMD gene. GNT0004 uses an adeno-associated virus serotype 8 vector to deliver a functional, but shortened, version of the DMD gene that encodes for the company's version of dystrophin, which is the protein deficient in people with this illness.
So far in clinical trials, patients have tolerated the intravenously injected gene therapy well when given in combination with transient immunological prophylactic treatment, according to Genethon. Investigators have observed improvements in microdystrophin expression with up to 85 percent of muscle fibers expressing microdystrophin eight weeks after treatment, and levels of CPK, a biomarker of muscular distress, have decreased by 50 percent to 87 percent 12 weeks after treatment. After one year, the first patient treated with GNT0004 at a second dose level showed functional improvement based on the North Star Ambulatory Assessment scale.
GNT0004 was developed by Genethon, a nonprofit laboratory based in Paris, in partnership with researchers at the Institute of Myology in Paris and Royal Holloway, University of London. The Phase I/II/III trial initially launched in 2021 but had to be paused when the first treated patient experienced a serious adverse event. The trial resumed in late 2022 after the adverse event resolved.