Duchenne muscular dystrophy: initial results of Genethon's gene therapy trial
The initial results of Genethon's gene therapy trial for Duchenne muscular dystrophy were presented on Tuesday 23 April at the Myology 2024 congress in Paris.
The trial, which combines phases I/II/III, is being conducted in France and the UK and includes boys aged 6 to 10 with Duchenne muscular dystrophy who have retained their ability to walk. It started in 2021 and was restarted at the end of 2022 after the resolution of a side effect experienced by the first patient, similar to those observed in other trials and discussed within a collaborative group between the sponsors of different gene therapy trials for this same disease.
Five children aged between 6 and 10 have been treated to date, 4 in France and 1 in the UK. 2 have been treated at the first dose and 3 at the second dose level. The safety and pharmacodynamic results presented at Myology 2024 show good tolerance of the treatment combined with transient immunological prophylaxis, as well as efficacy data, both in terms of microdystrophin expression and functional improvement. In patients treated at the second dose level, up to 85% (54% on average for the 3 patients) of muscle fibres expressing microdystrophin and a fall in CPK levels of between 50% and 87% were observed.
The efficacy results at one year for the first patient treated at the second dose level showed a positive clinical evolution, with an improvement in the NSAA clinical score (measurement scale). Other functions assessed (10-metre walking time, time to rise from the ground) confirmed a significant improvement in measurable performance.
For Serge Braun, Scientific Director of AFM-Téléthon: ‘The presentation of these results at our Myology 2024 congress represents a great moment for our Association. 38 years after the symposium on neuromuscular diseases in Tours, where the identification of the gene for Duchenne muscular dystrophy was announced, gene therapy is becoming a reality. The results presented are more than encouraging and encourage us to continue’.
On the strength of these results, Genethon is preparing for the pivotal stage of the trial with the European Medicines Agency (EMA).