Casimersen for the treatment of Duchenne muscular dystrophy

Casimersen is a single-stranded, antisense phosphorodiamidate morpholino oligonucleotide where six-membered morpholino rings substitute the ribofuranose rings of the natural DNA and RNA backbone. The morpholino is conjugated to the following monomer via a charge-neutral phosphorodiamidate instead of the phosphodiester linkage containing a negative charge. Phosphorodiamidate morpholino oligonucleotides are resistant to enzymatic degradation, and their lack of charge facilitates cellular penetration. The sequence of casimersen is 5′-CAATGCCATCCTGGAGTTCCTG-3′. It has a molecular formula of C268H424N124O95P22 with a molecular weight of 7584.5 Da.