Casimersen (SRP-4045) is an antisense oligonucleotide of the phosphorodiamidate morpholino oligomer subclass. Casimersen binds to exon 45 of dystrophin pre-mRNA, restores the open-reading frame (by skipping exon 45) resulting in the production of an internally truncated but functional dystrophin protein. Casimersen can be used for the research of Duchenne muscular dystrophy (DMD)[1].
Exon 45 skipping is intended to allow for production of an internally truncated dystrophin protein in patients with genetic mutations that are amenable to exon 45 skipping[2].
[1]. Shirley M. Casimersen: First Approval. Drugs. 2021;81(7):875-879. [2]. Casimersen. Am J Health Syst Pharm. 2021;78(13):1149-1150.