Viltepso (viltolarsen)

What is Viltepso (viltolarsen) for?

Viltepso (viltolarsen) is an antisense therapy indicated for the treatment of Duchenne muscular dystrophy (DMD) with a confirmed deficiency of the dystrophin gene amenable to exon 53 skipping therapy.^[1]

It is available in single-dose vial form containing 250 mg/5mL of viltolarsen.^[1]

How does Viltepso (viltolarsen) work?

Duchenne muscular dystrophy (DMD) is one of the most common lethal progressive muscle-wasting diseases that is occurring primarily in young boys. In patients with DMD, the protein dystrophin is not functioning properly. Dystrophin is crucial for muscle health, and dysfunctionality of it leads to muscle weakness and loss of muscles.^[2]

This aberrant production is caused by a mutation in the DMD gene. Most genes are composed of alternating ‘exons’, which contain a genetic code for the production of proteins, and ‘introns’, which do not contain a code. To produce a protein out of this genetic code, the cells make a temporary copy of the gene, called messenger RNA (mRNA). Subsequently, this mRNA will be ‘spliced’, in which the intron regions will be cut out of the mRNA and exons will be fused together, finalizing the complete code for the protein.^[2]

In some cases of DMD, certain parts of the DMD gene are not present, which causes the exons to not fit together properly. This disrupts the code, and leads to the production of a non-functional dystrophin protein.^[2]

Viltepso is an antisense oligonucleotide. It contains a piece of artificial mRNA that restores this disruption by fitting the exons together again. Viltepso is designed specifically for exon 53 of the DMD gene, so it is only effective in patients with a mutation that is amenable to exon 53 skipping.^[1,3]

Where has Viltepso (viltolarsen) been approved?

Viltepso (viltolarsen) was approved for the treatment of patients with Duchenne Muscular Dystrophy (DMD) who are amenable to exon 53 skipping therapy by:

• The Food and Drug Administration (FDA), USA on August 12, 2020.^[4]
• The Pharmaceuticals and Medical Devices Agency (PMDA), Japan, March 25, 2020.^[5]

The FDA has granted accelerated approval to Viltepso, and granted it with Priority Review, Fast Track, Orphan Drug and Rare Pediatric Disease designations.^[4]

The PMDA has granted Viltepso with “Sakigake” designation (i.e. the Japanese version of Breakthrough Therapy Designation), Orphan Disease designation, and designation of Conditional Early Approval System.^[5]

Please note that this medicine may have also been approved in other regions than the ones we’ve listed. If you have a question about its approval in a specific country feel free to contact our support team.

How is Viltepso (viltolarsen) taken?

The standard dosage is:^[1]

• 80 mg/kg of Viltepso administered intravenously once a week over 1 hour.

Serum cystatin C, urine dipstick, and urine protein-to-creatinine ratio should be measured before starting Viltepso treatment. It is recommended to monitor for kidney function during the course of treatment.^[1]

Complete information about Viltepso (viltolarsen) dosage and administration can be found in the prescribing information listed in our references section.^[1]

Note: Please consult with your treating doctor for personalised dosing and potential drug interactions.

Are there any known adverse reactions or side effects of Viltepso (viltolarsen)?

Common adverse reactions

The most common (≥15%) adverse reactions listed in the prescribing information include:^[1]

• Upper respiratory tract infection
• Injection site reaction
• Cough
• Loss of appetite (pyrexia)

Serious adverse reactions

No serious adverse reactions were mentioned in the prescribing information.^[1]

For a comprehensive list of side effects and adverse reactions please refer to the official prescribing information