Eteplirsen (EXONDYS51), an antisense oligonucleotide authorized in the United States, appears to be able to maintain walking in patients treated for 4 years

Eteplirsen (Exondys51) is an antisense oligonucleotide targeting exon 51 skipping in the DMD gene. Developed by the Sarepta Therapeutics and conditionally authorized on the US market, eteplirsen enables the production of dystrophin in muscle. 

Long-term walking preservation 

A publication from the Journal of Neuromuscular Diseases describes new results from one of the very first trials of etetplirsen including 12 participants with DMD aged 7 to 13 years who were walking at the time of inclusion. They relate to the data obtained from the 6-minute walk test in these boys after 4 years of weekly treatment with etetplirsen compared to the natural history data of the disease in boys with DMD, untreated and from Italian and Belgian DMD registers. 

After one year of treatment, 17% of participants (2/12) had lost walking, but after 4 years of treatment, all other participants were still walking, including those over the age of 14 (4/12). On average, these participants could walk 196.3 meters longer than the untreated cohort, a significant difference. In comparison, the mean age of loss of walking was 13 years in the untreated cohort, from the registers. In contrast, the difference in NSAA functional scores obtained after 3 years of treatment, between trial participants and in the registry cohort was not found to be significant. Data after 4 years of treatment could not be obtained. 

The results of this study are to be weighted due to a comparison, not directly to a placebo group, but to an untreated group, external to the study.

Other trials to assess the effectiveness of eteplirsen are ongoing, including one in France. 


Comparison of Long-term Ambulatory Function in Patients with Duchenne Muscular Dystrophy Treated with Eteplirsen and Matched Natural History Controls. Jerry R Mendell, Navid Khan, Nanshi Sha, Helen Eliopoulos, Craig M McDonald, Nathalie Goemans, Eugenio Mercuri, Linda P Lowes, Lindsay N Alfano, Eteplirsen Study Group. J Neuromuscul Dis. DOI: 10.3233/JND-200548