Viltotarsen for the treatment of Duchenne muscular dystrophy

Duchenne muscular dystrophy is the most common lethal X-linked genetic disorder, characterized by progressive muscle loss, with cardiac and respiratory complications. It is caused by a lack of dystrophin protein due to mutations in the DMD gene, which can disrupt the reading frame of the dystrophin primary transcript. Antisense oligonu-cleotides such as phosphorodiamidate morpholino oligomers (PMOs) can induce exon skipping during pre-mRNA splicing and restore the reading frame of the DMD primary transcript. The resulting dystrophin protein is internally deleted but partially functional. Viltolarsen, also known as NS-065/NCNP-01, is a PMO developed through comprehensive sequence optimization and is designed to skip exon 53 on the DMD primary transcript. Exclusion of exon 53 from the DMD primary transcript can treat 8-10% of DMD patients worldwide. This review paper summarizes the mechanism of action, pharmacokinetics and safety of viltolarsen from preclinical and clinical trials.