Top-line results from the full trial continue to be expected in the third quarter of 2018, the company said in a statement.
Summit's utrophin modulator, ezutromid, is a potential breakthrough treatment for sufferers of DMD, a fatal wasting disease that affects boys and young men.
Interim data from the trial has already revealed a statistically significant reduction in muscle damage and inflammation in patients after just 24-weeks.
"We believe the early improvements seen in muscle health in the interim data from PhaseOut DMD indicate ezutromid is reducing DMD disease severity. In the full trial results, we aim to see continued utrophin modulation and sustained changes in magnetic resonance parameters,” said Dr David Roblin, the chief medical officer and president of research & development at Summit.
"These results, if positive, could form the basis of a regulatory filing of ezutromid, bringing this universal treatment to patients more rapidly," he added.