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VILTEPSO is an exon-skipping therapy studied in children as young as 4 years

Exon 53 Icon

VILTEPSO is designed to bind to and induce skipping of exon 53 of the dystrophin pre-mRNA, resulting in the production of a shortened dystrophin protein that contains essential functional portions

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An estimated 10% of patients with DMD would be amenable to treatment with an exon 53 skipping therapy such as VILTEPSO*

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VILTEPSO was discovered through an innovative triple-screening approach designed to identify antisense oligonucleotides with the highest possible exon-skipping efficiency

Common deletions that are amenable to VILTEPSO treatment include, but are not limited to, 45-52, 47-52, 48-52, 49-52, 50-52, and 52 of the dystrophin gene.

mRNA=messenger RNA.

For children with DMD, early diagnosis can be instrumental to inform the management of progressive muscle deterioration and motor function decline

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VILTEPSO is for DMD patients with a confirmed mutation that is amenable to exon 53 skipping

Exon skipping is a genetic technique that, in essence, “skips over” an exon next to the deleted exon(s) in patients with DMD.

  • There are nearly 50 DMD gene mutations that can be treated with VILTEPSO, including, but not limited to, 45-52, 47-52, 48-52, 49-52, 50-52, and 52 of the dystrophin gene
  • An estimated 10% of patients with DMD are amenable to treatment with VILTEPSO
  • In the United States, about 2% of patients with DMD have an exon 52 deletion that is amenable to treatment with VILTEPSO



VILTEPSO provided significant improvements in dystrophin expression

Study 1: Mean increase in dystrophin expression to nearly 6% of normal with VILTEPSO (80 mg/kg/wk) vs 0.6% at baseline

Study 1 Graph 1 Study 1 Graph 1
  • Efficacy was assessed by validated Western blot (normalized to myosin heavy chain) based on the change from baseline in dystrophin protein level, measured as percentage of the dystrophin level in healthy subjects at week 25
  • Mean change in dystrophin was 5.3% (SD 4.5) of normal levels (P=0.01)
    • Median change from baseline was 3.8%


P-value for change from baseline at week 25 was statistically significant.

Study design: A 2-period, North American dose-finding study with ambulant males aged 4 to <10 years with a confirmed mutation of the DMD gene amenable to exon 53 skipping who were receiving a stable dose of corticosteroids for ≥3 months (N=16). Primary study endpoints were safety, tolerability, and dystrophin protein production (Western blot). Secondary study endpoints were other dystrophin measures (RT-PCR, MS, and IFS) and timed motor function tests (6MWT, TTCLIMB, TTRW, TTSTAND) and NSAA. Patients were treated for 24 weeks, and then all patients elected to continue in an open-label, up to 192-week extension study for further assessment.

IFS=immunofluorescence staining; MS=mass spectrometry; NSAA=North Star Ambulatory Assessment; QMT=quantitative muscle testing;
RT-PCR=reverse transcriptase-polymerase chain reaction; 6MWT=6-minute walk test; SD=standard deviation; TTCLIMB=time to climb 4 stairs;
TTRW=time to run/walk 10 meters; TTSTAND=time to stand from supine.

Dystrophin Icon

DYSTROPHIN WHERE IT MATTERS: Immunofluorescence staining showed VILTEPSO-induced increases in dystrophin levels were correctly localized to the muscle cell membrane, where dystrophin is needed to support muscle health.

100% of patients showed an increase in dystrophin levels with VILTEPSO

Study 1: Dystrophin levels at 25 weeks vs baseline

Dystrophin expression (% of normal) normalized to myosin heavy chain

Study 1 Graph 2 Study 1 Graph 2
  • In a clinical study of patients aged 4 to <10 years, 100% of patients showed an increase in dystrophin levels with VILTEPSO, with a mean increase in dystrophin expression to ~6% of normal vs 0.6% at baseline
  • The statistically significant increase in dystrophin expression was measured by Western blot analysis, which is a validated, highly sensitive, and reproducible methodology

In the same 24-week study,
Secondary endpoint results provided additional evidence of dystrophin production

Secondary Endpoint data Secondary Endpoint data

Mean dystrophin levels as assessed by mass spectrometry (normalized to filamin C) increased from 0.6% (SD 0.2) of normal at baseline to 4.2% (SD 3.7) of normal by week 25, with a mean change in dystrophin of 3.7% (SD 3.8) of normal levels (nominal P=0.03, not adjusted for multiple comparisons); the median change from baseline was 1.9%.

In the same 24-week study,
Secondary endpoints included several motor function tests

Functional tests were secondary endpoints of study 201 and were compared to Duchenne natural history data, which is not considered an adequate comparator arm. Functional data are not in the US Prescribing Information, and therefore definitive conclusions should not be drawn.

Secondary Endpoint data Secondary Endpoint data

The control subjects for this trial were matched for age and corticosteroids from the CINRG-DNHS registry.


Negative velocity means lower rate of velocity; positive velocity means higher rate of velocity.

Negative time means less time; positive time means more time.

Negative number means less distance traveled; positive number means greater distance traveled.


Negative number means a lower score relative to baseline; positive number means a higher score relative to baseline.

CINRG=Cooperative International Neuromuscular Research Group; DNHS=Duchenne Natural History Study.


Safety profile evaluated in two 24-week clinical studies

Adverse reactions reported in ≥10% of DMD patients treated with VILTEPSO 80 mg/kg once weekly

Dosing Table Dosing Table


Upper respiratory tract infection includes the following terms: upper respiratory tract infection, nasopharyngitis, and rhinorrhea.


Injection site reaction includes the following terms: injection site bruising, injection site erythema, injection site reaction, and injection site swelling.


VILTEPSO offers a choice of treatment location—at home or at a treatment center

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VILTEPSO is given as an 80-mg/kg weekly intravenous infusion

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The appropriate dose of VILTEPSO is calculated based upon patient weight, at a recommended weekly dose of 80 mg/kg

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VILTEPSO is infused for 60 minutes by a healthcare professional, either at the patient’s home or at a treatment center


Determining dosing for VILTEPSO infusion

VILTEPSO is available as single-dose vials containing 250 mg/5mL (50 mg/mL) solution. The appropriate dose is based on patient’s body weight, with the recommended dosage of VILTEPSO 80 mg/kg administered once weekly as a 60-minute intravenous infusion.

Weekly dosing chart

Only odd kg body weight provided for illustrative purposes.

Dosing Chart table headers Weekly dosing chart by weight
Dosing Chart table headers Weekly dosing chart by weight

If volume of VILTEPSO required is <100 mL, dilution in 0.9% sodium chloride for injection, USP, is required such that the total volume in the infusion bag is 100 mL. If the volume of VILTEPSO to be infused is ≥100 mL, dilution is not required.

The actual number of theoretical vials required is 15.04.

When less than 100 mL of VILTEPSO is required:


Withdraw from the 100‑mL infusion bag a volume of 0.9% sodium chloride for injection, USP, equivalent to the calculated volume of VILTEPSO solution that will be added.


Withdraw the calculated volume of VILTEPSO solution from the appropriate number of vials, and inject into the infusion bag, such that the total volume in the bag is 100 mL.

When 100 mL or more of VILTEPSO is required:

Withdraw the calculated volume of VILTEPSO solution from the appropriate number of vials, and inject into an empty infusion bag. Further dilution is not required if the volume of VILTEPSO is 100 mL or more.

After preparation, VILTEPSO infusion
should begin as soon as possible

5 hours icon

Infusion should begin no more than 5 hours after preparation of VILTEPSO and be completed within 6 hours of preparation (allowing for 1 hour of infusion time) if diluted solution is stored at 20°C to 26°C (68°F to 79°F).

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VILTEPSO is administered via intravenous infusion using a peripheral or central venous catheter. Flush the intravenous access line with 0.9% sodium chloride for injection, USP, after infusion. Filtration of VILTEPSO is not required.

No mixing icon

Do not mix other medications with VILTEPSO or infuse other medications concomitantly via the same intravenous access line.

VILTEPSO Pocket Dosing Guide

This guide serves as a quick reference for information on appropriate VILTEPSO dose and number of corresponding VILTEPSO vials, as well as corresponding volumes of saline, VILTEPSO, and total volume of VILTEPSO solution, for select patient body weights.

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Product Order Form

Complete this form and fax or mail it to NS Support to order VILTEPSO for your appropriate patients with Duchenne muscular dystrophy (DMD) who are amenable to exon 53 skipping.

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VILTEPSO is 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 VILTEPSO. Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial.

For more information about VILTEPSO, see full Prescribing Information.

Important Safety Information

  • Warnings and Precautions: Kidney toxicity was observed in animals who received viltolarsen. Although kidney toxicity was not observed in the clinical studies with VILTEPSO, the clinical experience with VILTEPSO 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 VILTEPSO. 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 VILTEPSO. Consider also measuring glomerular filtration rate before starting VILTEPSO. During treatment, monitor urine dipstick every month, and serum cystatin C and urine protein-to-creatinine ratio every three months.
  • Urine should be free of excreted VILTEPSO for monitoring of urine protein. Obtain urine either prior to VILTEPSO infusion, or at least 48 hours after the most recent infusion. Alternatively, use a laboratory test that does not use the reagent pyrogallol red, which has the potential to generate a false positive result due to cross reaction with any VILTEPSO in the urine. If a persistent increase in serum cystatin C or proteinuria is detected, refer to a pediatric nephrologist for further evaluation.
  • Adverse Reactions: The most common adverse reactions include upper respiratory tract infection, injection site reaction, cough, and pyrexia.
  • To report an adverse event, or for general inquiries, please call NS Pharma Medical Information at 1-866-NSPHARM (1-866-677-4276).

For more information about VILTEPSO, see full Prescribing Information.