Development of Duchenne muscular dystrophy gene therapy stopped

7 November 2024

Sarepta Therapeutics have announced they are stopping the development of SRP-5051 (vesleteplirsen). Vesleteplirsen was being tested as a treatment for Duchenne muscular dystrophy (DMD), in people that may benefit from exon 51 skipping. This means the phase 2 clinical trial, MOMENTUM, investigating the safety and efficacy of vesleteplirsen, has stopped.

Vesleteplirsen was an experimental genetic therapy designed to produce a protein called dystrophin, by skipping exon 51 of the dystrophin gene. People with DMD lack dystrophin which is required to maintain the strength of muscles.

The trial was stopped due to concerns over side effects. Early in the study, hypomagnesemia (low blood magnesium levels) was seen but considered manageable. However, for some participants the hypomagnesemia continued, even when they stopped receiving vesleteplirsen. Some participants also had a decline in a test for kidney function. While vesleteplirsen was showing encouraging levels of dystrophin, Sarepta decided the potential risks outweighed any potential benefits.

We’re disappointed that the work on vesleteplirsen won’t be continuing but safety is vital.  

Sarepta will continue to review the data from the trial and share updates at future scientific meetings. While this is not the outcome we wanted, the learnings from this trial could help the development of other potential treatments.

If you or your family member has been involved in the study, we recommend that you contact the study site for any further information. Sarepta have also released a letter to the community.