The Food and Drug Administration (FDA) has granted approval for Amondys 45 (casimersen; Sarepta Therapeutics Inc.) injection for the treatment of Duchenne muscular dystrophy (DMD) in patients who have a confirmed mutation of the DMD gene that is amenable to exon 45 skipping.

DMD is a rare genetic disorder characterized by progressive muscle deterioration and weakness; it is the most common type of muscular dystrophy. DMD is caused by mutations in the DMD gene that result in an absence of dystrophin, a protein found in muscle fiber. The FDA approved Amondys 45 based on an increase in dystrophin production in skeletal muscle observed in patients treated with the therapy. This is the first FDA-approved targeted treatment for patients with this type of mutation.

Amondys 45 is an intravenously administered antisense oligonucleotide (AON) that uses a proprietary phosphorodiamidate morpholino oligomer (PMO) chemistry and exon-skipping technology. Approval for Amondys 45 is supported by clinical trial results. Amondys 45 has also been granted Orphan Drug designation, which provides incentives to assist and encourage the development of drugs for rare diseases.

Food and Drug Administration (FDA). FDA Approves Targeted Treatment for Rare Duchenne Muscular Dystrophy Mutation [news release]. February 25, 2021. Available at: click here. Accessed February 25, 2021.