Phase 2 Study of EDG-5506 in Becker Muscular Dystrophy (GRAND CANYON)

To have been able to join the main GRAND CANYON study, participants needed to be men between 18 and 50 years old. They must have had a confirmed diagnosis of Becker muscular dystrophy and have been able to walk on their own until at least 16 years old (or 18 years old if they were using certain steroid medicines).

Participants also needed to be able to complete a 100-meter walk within 200 seconds, with or without walking aids. Their muscle function, as measured by a specific test called the North Star Ambulatory Assessment, needed to fall within a certain range.

However, some things would have meant someone couldn't join. For example, if they had other serious health problems, certain heart or lung issues, or had taken specific steroid medicines or other trial drugs recently. People who couldn't have an MRI scan (for example, due to certain metal implants) would also have been excluded.

If you had joined the GRAND CANYON study, you would first have had a screening period lasting up to 4 weeks to check if you were suitable. After that, you would have been randomly assigned to either receive sevasemten or a placebo, which looks identical but has no active medicine. You wouldn't have known which one you were taking, and neither would your doctors.

The treatment period would have lasted for 18 months, during which you would have regularly taken the study medicine. Throughout this time, you would have had various clinic visits for assessments, including checks on your safety, how the medicine was affecting your body, and changes in your muscle function and movement. After the 18-month treatment period, there would have been a follow-up period of 4 weeks to see how you were doing.