Amondys

Amondys is the brand name for casimersen, a phosphorodiamidate morpholino oligomer (PMO) antisense oligonucleotide used to treat Duchenne muscular dystrophy (DMD). It is designed to induce skipping of dystrophin exon 45 in patients whose mutations are amenable to exon 45 skipping, enabling production of a truncated but potentially functional dystrophin protein.

Medical use: Amondys is indicated for the treatment of DMD in patients who have a confirmed DMD gene mutation that would be amenable to exon 45 skipping. It targets a mutation-specific subgroup of DMD patients and is intended to be used as part of a mutation-appropriate exon-skipping strategy.

Mechanism of action: Casimersen binds to dystrophin pre-mRNA to modulate splicing and exclude exon 45, restoring the reading frame and allowing production of dystrophin rather than a frameshift mutation.

Administration: The drug is given by intravenous infusion, with a weight-based dose administered at regular intervals, typically weekly.

Safety and monitoring: The safety profile includes common infusion-related reactions and injection-site reactions. As with other PMO therapies, ongoing monitoring of renal and hepatic function is advised, and long-term safety data are being collected in clinical studies.

Regulatory status: In 2021, the U.S. Food and Drug Administration approved Amondys for exon 45 skipping in eligible DMD patients, making it one of several mutation-specific exon-skipping therapies for the disease.

See also: Exondys 51 (eteplirsen), Vyondys 53 (golodirsen), Viltepso (viltolarsen).