Conclusions
DMD
The study outcome of improved motor function vs historical controls, and a favorable safety profile, have been demonstrated in the longest exon 53 skipping therapy trial to date. This is the only study of an exon 53 skipping agent used to demonstrate significant functional benefit over 4 years with comparison to a group-matched, prospectively collected, control group. Based on the efficacy and safety data reported here, combined with the previously reported significant increase in dystrophin levels in these same participants, viltolarsen can be an important part of the treatment strategy for DMD patients who have mutations that are amenable to exon 53 skipping.