ACT DMD enrolled boys aged 7−16 years with nmDMD, a baseline 6-minute walk distance (6MWD) of 150 m or more and having ≤80% of the predicted normal value at baseline (n=228).  The North Star Ambulatory Assessment (NSAA) is a validated tool that assesses disease progression in ambulatory boys with DMD. NSAA is comprised of 17 tasks that patients are evaluated on at each clinic visit, with the possible values for each item being 0, 1, or 2, where 0=unable to perform task, 1=performs with difficulty and 2=able to perform.  In this analysis, loss of function (failures) from 17 tasks was evaluated for each patient (i.e., 2 to 0, or 1 to 0) at various time points over the entire study duration. The average cumulative number of failures over time was then obtained over all patients in each treatment group, and was plotted to show the temporal profile of treatment.

The curve for the placebo was uniformly higher than that of ataluren. The ratio of the above two curves was used as an overall measure of treatment effect (i.e., treatment divided by placebo). This analysis resulted in a ratio of 0.73 (95% CI, 0.55-0.97; p=0.027), indicating that ataluren treatment significantly reduces the cumulative number of failures by 27% over 48 weeks compared to placebo.

The results suggest preservation of physical function with ataluren therapy in ambulatory boys with nmDMD.