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Viltolarsen (Monograph)

Brand name: Viltepso
Drug class: Antisense Oligonucleotides
Chemical name: 1-[(2R,6S)-6-[[[(2S,6R)-2-[[[(2R,6S)-2-(2-amino-6-oxo-1H-purin-9-yl)-6-[[[(2S,6R)-2-[[[(2R,6S)-2-(2-amino-6-oxo-1H-purin-9-yl)-6-[[[(2R,6S)-2-(2-amino-6-oxo-1H-purin-9-yl)-6-[[[(2S,6R)-2-[[[(2S,6R)-2-[[[(2R,6S)-2-(2-amino-6-oxo-1H-purin-9-yl)-6-[[[(2S,6R)-2-[[[(2S,6R)-2-[[[(2S,6R)-2-[[[(2S,6R)-2-[[[(2R,6S)-2-(2-amino-6-oxo-1H-purin-9-yl)-6-[[[(2R,6S)-2-(2-amino-6-oxo-1H-purin-9-yl)-6-[[[(2R,6S)-2-(4-amino-2-oxopyrimidin-1-yl)-6-[[[(2R,6S)-2-(4-amino-2-oxopyrimidin-1-yl)-6-[[[(2S,6R)-2-[[[(2R,6S)-2-(4-amino-2-oxopyrimidin-1-yl)-6-[[[(2R,6S)-2-(4-amino-2-oxopyrimidin-1-yl)-6-(hydroxymethyl)morpholin-4-yl]-(dimethylamino)phosphoryl]oxymethyl]morpholin-4-yl]-(dimethylamino)phosphoryl]oxymethyl]-6-(5-methyl-2,4-dioxopyrimidin-1-yl)morpholin-4-yl]-(dimethylamino)phosphoryl]oxymethyl]morpholin-4-yl]-(dimethylamino)phosphoryl]oxymethyl]morpholin-4-yl]-(dimethylamino)phosphoryl]oxymethyl]morpholin-4-yl]-(dimethylamino)phosphoryl]oxymethyl]morpholin-4-yl]-(dimethylamino)phosphoryl]oxymethyl]-6-(5-methyl-2,4-dioxopyrimidin-1-yl)morpholin-4-yl]-(dimethylamino)phosphoryl]oxymethyl]-6-(5-methyl-2,4-dioxopyrimidin-1-yl)morpholin-4-yl]-(dimethylamino)phosphoryl]oxymethyl]-6-(4-amino-2-oxopyrimidin-1-yl)morpholin-4-yl]-(dimethylamino)phosphoryl]oxymethyl]-6-(5-methyl-2,4-dioxopyrimidin-1-yl)morpholin-4-yl]-(dimethylamino)phosphoryl]oxymethyl]morpholin-4-yl]-(dimethylamino)phosphoryl]oxymethyl]-6-(6-aminopurin-9-yl)morpholin-4-yl]-(dimethylamino)phosphoryl]oxymethyl]-6-(6-aminopurin-9-yl)morpholin-4-yl]-(dimethylamino)phosphoryl]oxymethyl]morpholin-4-yl]-(dimethylamino)phosphoryl]oxymethyl]morpholin-4-yl]-(dimethylamino)phosphoryl]oxymethyl]-6-(5-methyl-2,4-dioxopyrimidin-1-yl)morpholin-4-yl]-(dimethylamino)phosphoryl]oxymethyl]morpholin-4-yl]-(dimethylamino)phosphoryl]oxymethyl]-6-(5-methyl-2,4-dioxopyrimidin-1-yl)morpholin-4-yl]-(dimethylamino)phosphoryl]oxymethyl]-4-[[(2S,6R)-6-(4-amino-2-oxopyrimidin-1-yl)morpholin-2-yl]methoxy-(dimethylamino)phosphoryl]morpholin-2-yl]-5-methylpyrimidine-2,4-dione
Molecular formula: C244H381N113O88P20


Viltolarsen is an antisense oligonucleotide of the phosphorodiamidate morpholino oligomer (PMO) subclass.

Uses for Viltolarsen

Viltolarsen has the following uses:

Viltolarsen is an antisense oligonucleotide indicated for the treatment of Duchenne muscular dystrophy (DMD) in patients who have a confirmed mutation of the DMD gene that is amenable to exon 53 skipping.

This indication is approved under accelerated approval based on an increase in dystrophin production in skeletal muscle observed in patients treated with viltolarsen. Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial.

Viltolarsen Dosage and Administration


Viltolarsen is available in the following dosage form(s) and strength(s):

Injection: 250 mg/5 mL (50 mg/mL) in a single-dose vial.


It is essential that the manufacturer's labeling be consulted for more detailed information on dosage and administration of this drug. Dosage summary:

Pediatric Patients

Dosage and Administration


Dosage and Administration

Cautions for Viltolarsen




Kidney Toxicity

Kidney toxicity was observed in animals who received viltolarsen. Although kidney toxicity was not observed in the clinical studies with viltolarsen, the clinical experience with viltolarsen is limited, and kidney toxicity, including potentially fatal glomerulonephritis, has been observed after administration of some antisense oligonucleotides. Kidney function should be monitored in patients taking viltolarsen. Because of the effect of reduced skeletal muscle mass on creatinine measurements, serum creatinine may not be a reliable measure of kidney function in DMD patients. Serum cystatin C, urine dipstick, and urine protein-to-creatinine ratio should be measured before starting viltolarsen. Consider also measuring glomerular filtration rate using an exogenous filtration marker before starting viltolarsen. During treatment, monitor urine dipstick every month, and serum cystatin C and urine protein-to-creatinine ratio every three months. If a persistent increase in serum cystatin C or proteinuria is detected, refer to a pediatric nephrologist for further evaluation.

Specific Populations


Risk Summary

There are no human or animal data available to assess the use of viltolarsen during pregnancy. In the U.S. general population, major birth defects occur in 2 to 4%, and miscarriage occurs in 15 to 20% of clinically recognized pregnancies.


Risk Summary: There are no human or animal data to assess the effect of viltolarsen on milk production, the presence of viltolarsen in milk, or the effects of viltolarsen on the breastfed infant.

The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for viltolarsen and any potential adverse effects on the breastfed infant from viltolarsen or from the underlying maternal condition.

Pediatric Use

Viltolarsen is indicated for the treatment of DMD in patients who have a confirmed mutation of the DMD gene that is amenable to exon 53 skipping, including pediatric patients.

Juvenile Animal Toxicity Data: Viltolarsen (0, 15, 60, 240, or 1200 mg/kg) was administered to juvenile male mice by subcutaneous injection on postnatal day (PND) 7 and by intravenous injection weekly from PND 14 to PND 70. The highest dose resulted in deaths because of renal toxicity. In surviving animals at 240 and 1200 mg/kg, there was a dose-dependent increase in the incidence and severity of renal tubular effects (including degeneration), which were not accompanied by clinical pathology correlates. Reduced body weight gain and delayed sexual maturation were observed at the highest dose tested. At the no-effect dose for renal toxicity (60 mg/kg), plasma exposures were similar to that in humans at the recommended human dose of 80 mg/kg/week.

Geriatric Use

DMD is largely a disease of children and young adults; therefore, there is no geriatric experience with viltolarsen.

Patients with Renal Impairment

Viltolarsen has not been studied in patients with renal impairment. Viltolarsen is mostly excreted unchanged in the urine, and renal impairment may increase its exposure. However, because of the effect of reduced skeletal muscle mass on creatinine measurements in DMD patients, no specific dosage adjustment can be recommended for DMD patients with renal impairment based on estimated glomerular filtration rate. Patients with known renal function impairment should be closely monitored during treatment with viltolarsen.

Common Adverse Effects

The most common adverse reactions (incidence ≥15% in patients treated with viltolarsen) were upper respiratory tract infection, injection site reaction, cough, and pyrexia.

Drug Interactions

Specific Drugs

It is essential that the manufacturer's labeling be consulted for more detailed information on interactions with this drug, including possible dosage adjustments. Interaction highlights:

Please see product labeling for drug interaction information.


Mechanism of Action

Viltolarsen is designed to bind to exon 53 of dystrophin pre-mRNA resulting in exclusion of this exon during mRNA processing in patients with genetic mutations that are amenable to exon 53 skipping. Exon 53 skipping is intended to allow for production of an internally truncated dystrophin protein in patients with genetic mutations that are amenable to exon 53 skipping.

Advice to Patients

Kidney Toxicity

Inform patients nephrotoxicity has occurred with drugs similar to viltolarsen. Advise patients of the importance of monitoring for kidney toxicity by their healthcare providers during treatment with viltolarsen.

Additional Information

AHFSfirstRelease. For additional information until a more detailed monograph is developed and published, the manufacturer's labeling should be consulted. It is essential that the manufacturer's labeling be consulted for more detailed information on usual uses, dosage and administration, cautions, precautions, contraindications, potential drug interactions, laboratory test interferences, and acute toxicity.


Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.



Dosage Forms


Brand Names



Injection, Solution, for IV infusion

50 mg/mL


NS Pharma Inc.

AHFS DI Essentials™. © Copyright 2024, Selected Revisions August 24, 2020. American Society of Health-System Pharmacists, Inc., 4500 East-West Highway, Suite 900, Bethesda, Maryland 20814.

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Frequently asked questions