Viltepso is a brand-name prescription medication. It’s used to treat Duchenne muscular dystrophy (DMD) in people who have a certain gene mutation.* DMD is a condition that affects your muscles and causes them to become progressively weaker.

Specifically, Viltepso is approved for use in adults and in children ages 4 years to 17 years old with DMD who are missing a part of their DMD gene called exon 53. See the “Viltepso uses” section below for more information about how the drug’s used.

Note: Clinical trials of Viltepso only involved male† children ages 4 years to 17 years old. The studies didn’t include any female† children or any adults.

* A gene mutation is an abnormal change in a gene.
† In this article, the terms male and female refer to a person’s sex assigned at birth.

Drug details

Viltepso is given by a healthcare provider as an intravenous infusion. This is an injection that’s given over time into a vein in your arm. The drug comes as a solution in one strength: 250 milligrams/5 milliliters.

Viltepso contains the active drug viltolarsen. The drug belongs to a group of medications called antisense oligonucleotides. It works to help your body make a protein called dystrophin. This protein helps you move and flex your muscles.

FDA approval

Viltepso was approved by the Food and Drug Administration (FDA) in August 2020 to treat DMD in certain situations. The drug received accelerated approval from the FDA. This means that it was approved based on early results of clinical trials.

Typically, drugs receive approval from the FDA after extensive studies have been completed. But for some drugs, such as Viltepso, approval is granted before all of the studies have been done. Accelerated approval may be given in certain cases when there aren’t many other options for treating a disease. And there are very few treatment options for DMD. The FDA’s decision for full approval of Viltepso will be made after more clinical trials have been completed.

Effectiveness

For information about the effectiveness of Viltepso, see the “Viltepso uses” section below.

Viltepso is available only as a brand-name medication. It contains the active drug viltolarsen, which is not currently available in a generic form.

A generic drug is an exact copy of the active drug in a brand-name medication. Generics usually cost less than brand-name drugs.

As with all medications, the cost of Viltepso can vary. To find current prices for Viltepso in your area, check out WellRx.com.

The cost you find on WellRx.com is what you may pay without insurance. The actual price you’ll pay depends on your insurance plan, your location, and the pharmacy you use.

Before approving coverage for Viltepso, your insurance company may require you to get prior authorization. This means that your doctor and insurance company will need to communicate about your prescription before the insurance company will cover the drug. The insurance company will review the prior authorization request and decide if the drug will be covered.

If you’re not sure if you’ll need to get prior authorization for Viltepso, contact your insurance company.

Financial and insurance assistance

If you need financial support to pay for Viltepso, or if you need help understanding your insurance coverage, help is available.

NS Pharma, Inc., the manufacturer of Viltepso, offers a program called NS Support that may help lower the cost of this drug. For more information and to find out if you’re eligible for support, call 833-NSSUPRT (833-677-8778) or visit the program website.

Generic version

Viltepso isn’t available in a generic form. A generic drug is an exact copy of the active drug in a brand-name medication. Generics tend to cost less than brand-name drugs.

The Viltepso dosage your doctor prescribes will depend on your body weight. This drug is a weight-based medication, which means that the dosage is calculated based on your body weight.

The following information describes dosages that are commonly used or recommended. But be sure to take the dosage your doctor prescribes for you. They’ll determine the best dosage to fit your needs.

Drug forms and strengths

Viltepso comes as a solution. It’s given by a healthcare provider as an intravenous infusion. This is an injection that’s given over time into a vein in your arm. Viltepso infusions last for about 1 hour.

Viltepso comes in a strength of 250 milligrams (mg)/5 milliliters.

Dosage for Duchenne muscular dystrophy

The Viltepso dosage for Duchenne muscular dystrophy (DMD) depends on your body weight. The recommended dosage for Viltepso is 80 mg per kilogram (kg) of body weight given once a week. One kg is equal to about 2.2 pounds (lb).

For example, if you weigh 165 lb (75 kg), your dosage would be 6,000 mg once a week.

Children’s dosage

Viltepso has only been studied in male children ages 4 years to 17 years. The dosage listed directly above, under “Dosage for Duchenne muscular dystrophy,” is the recommended dosage for children and adults: 80 mg/kg once a week.

What if I miss a dose?

If you miss an infusion of Viltepso, be sure to reschedule your appointment to get your missed dose as soon as possible.

To help make sure that you don’t miss a dose, try using a medication reminder. This can include setting an alarm or timer on your phone or downloading a reminder app.

Will I need to use this drug long term?

Viltepso is meant to be used as a long-term treatment. If you and your doctor determine that Viltepso is safe and effective for you, you’ll likely take it long term.

Viltepso can cause mild or serious side effects. The following lists contain some of the key side effects that may occur while taking Viltepso. These lists do not include all possible side effects.

For more information about the possible side effects of Viltepso, talk with your doctor or pharmacist. They can give you tips on how to deal with any side effects that may be concerning or bothersome.

Note: The Food and Drug Administration (FDA) tracks side effects of drugs it has approved. If you’d like to notify the FDA about a side effect you’ve had with Viltepso, you can do so through MedWatch.

Mild side effects

Mild side effects* of Viltepso can include:

Most of these side effects may go away within a few days or a couple of weeks. But if they become more severe or don’t go away, talk with your doctor or pharmacist.

* This is a partial list of mild side effects from Viltepso. To learn about other mild side effects, talk with your doctor or pharmacist or view Viltepso’s prescribing information.
† For more information about this side effect, see “Side effect details” below.

Serious side effects

Serious side effects from Viltepso aren’t common, but they can occur. Call your doctor right away if you have serious side effects. Call 911 or your local emergency number if your symptoms feel life threatening or you think you’re having a medical emergency.

Serious side effects and their symptoms can include:

  • Kidney problems. Symptoms can include:
    • fatigue (lack of energy)
    • urinating more than usual
    • blood in your urine
  • Allergic reaction.*
  • Decreased ejection fraction (meaning that your heart doesn’t pump out blood as well usual).*

* For more information about this side effect, see “Side effect details” below.

Side effects in children

Two clinical trials were done to study people taking Viltepso. The first trial included children ages 4 years to 9 years old. The second trial included children ages 5 years to 17 years old. So, all of the side effects described in this article are side effects that occurred in children.

Side effect details

You may wonder how often certain side effects occur with this drug. Here’s some detail on certain side effects this drug may cause.

Allergic reaction

As with most drugs, some people can have an allergic reaction after taking Viltepso. It isn’t known how many children may have had an allergic reaction when taking Viltepso in clinical trials.

Symptoms of a mild allergic reaction can include:

  • rash (see below)
  • itchiness
  • flushing (warmth, swelling, or redness in your skin)

A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include:

  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your tongue, mouth, or throat
  • trouble breathing

Call your doctor right away if you have an allergic reaction to Viltepso, as the reaction could become severe. Call 911 or your local emergency number if your symptoms feel life threatening or you think you’re having a medical emergency.

Rash

Rashes or hives are common side effects of Viltepso. And keep in mind that a rash can be a symptom of allergic reaction, which could become serious if it’s not treated.

In a clinical trial, 13% of children taking Viltepso experienced a rash while taking the drug.*

Talk with your doctor if you notice a rash or hives after taking Viltepso.

Note: A rash can also be a symptom of an injection site reaction. This is another possible side effect of Viltepso. See “Injection site reactions” below for more details.

* In this trial, Viltepso wasn’t compared with other medications or a placebo. A placebo is a treatment with no active drug.

Upper respiratory tract infection

Viltepso may cause upper respiratory tract infections, such as the common cold. Symptoms may include:

  • fever
  • headache
  • throat pain
  • cough

In clinical trials, upper respiratory tract infections occurred in 63% of children who took Viltepso.*

If you have an upper respiratory infection while taking Viltepso, talk with your doctor. They may recommend that you take antibiotics or monitor your infection to be sure that it improves.

* In these trials, Viltepso wasn’t compared with other medications or a placebo. A placebo is a treatment with no active drug.

Injection site reactions

Injection site reactions are a common side effect of Viltepso. Injection site reactions affect the area where Viltepso is injected into your body. Symptoms may include redness, swelling, and bruising.

In clinical trials, 25% of children taking Viltepso had injection site reactions.*

If you experience an injection site reaction while you’re taking Viltepso, talk with your doctor. They may be able to recommend ways to reduce this side effect.

* In these trials, Viltepso wasn’t compared with other medications or a placebo. A placebo is a treatment with no active drug.

Bruising

Viltepso infusions may cause bruising to develop around the injection site.

In clinical trials, 25% of children had injection site reactions after Viltepso infusions. These reactions may have included bruising, redness, swelling, or other reactions. But isn’t known how many children specifically had bruising.*

Talk with your doctor if you frequently experience bruising after your infusion. They may be able to recommend ways to reduce this side effect.

* In these trials, Viltepso wasn’t compared with other medications or a placebo. A placebo is a treatment with no active drug.

Gastrointestinal problems

Gastrointestinal problems are common side effects of Viltepso. These problems may include diarrhea, vomiting, and abdominal (belly) pain.

In clinical trials, diarrhea, vomiting, and abdominal pain each occurred in 13% of children taking Viltepso.*

If you have gastrointestinal problems during your Viltepso treatment, talk with your doctor. They may be able to recommend ways to decrease discomfort caused by these side effects.

* In these trials, Viltepso wasn’t compared with other medications or a placebo. A placebo is a treatment with no active drug.

Decreased ejection fraction

It’s possible for Viltepso to cause a decreased ejection fraction. Ejection fraction is a measure of how much blood your heart pumps out when it beats. Having a decreased ejection fraction means that your heart isn’t pumping blood as much blood as it should.

Symptoms of a decreased ejection fraction include:

  • trouble breathing
  • swelling of your ankles and feet
  • fatigue (lack of energy)

In clinical trials, 13% of children taking Viltepso experienced a decreased ejection fraction.*

If you have any symptoms of a decreased ejection fraction, talk with your doctor right away. They may recommend tests to check that your heart is functioning properly.

* In these trials, Viltepso wasn’t compared with other medications or a placebo. A placebo is a treatment with no active drug.

The Food and Drug Administration (FDA) approves prescription drugs such as Viltepso to treat certain conditions. Viltepso may also be used off-label for other conditions. Off-label drug use means using a drug for a purpose other than what it’s been approved for by the FDA.

Viltepso for Duchenne muscular dystrophy

Viltepso is approved to treat Duchenne muscular dystrophy (DMD) in people who have a certain gene mutation.* DMD is a condition that affects your muscles and causes them to become progressively weaker. Usually, DMD affects males. Rarely, DMD can also affect females.

DMD is an inherited condition. Symptoms usually begin during childhood, between the ages of 2 years and 3 years old. Symptoms may include:

  • falling down more often than usual
  • muscle pain, stiffness, or weakness
  • trouble sitting, standing up, walking, or running
  • developmental delays, such as delayed speech

Life expectancy for people with DMD has improved greatly over the past few decades. This is due to improvements in treatment options. At this time, life expectancy for people with DMD is 21 years to 39.6 years.

DMD is caused by a mutation in your genes. And Viltepso is approved for use specifically in people with DMD who are missing part of their DMD gene called exon 53. When exon 53 is missing, your body doesn’t properly produce a protein called dystrophin. Dystrophin allows you to move and flex your muscles. Without dystrophin, your muscles can weaken and eventually deteriorate (break down).

Viltepso works to allow your body to “skip” the missing exon 53 part of your gene. This allows your body to produce dystrophin. (See the “How Viltepso works” section below for more information.)

It’s important to note that Viltepso doesn’t work to treat all forms of DMD. It only works to treat DMD that may respond to “skipping” of exon 53. There are other genetic changes that may also cause DMD, such as changes that affect a different part of the DMD gene called exon 51. If you have a genetic change other than a missing exon 53, your doctor may recommend a drug other than Viltepso for you.

* A gene mutation is an abnormal change in a gene.

Effectiveness for DMD

In one clinical trial, Viltepso was safe and effective for treating DMD in male children who were missing exon 53.

This trial monitored how much dystrophin children with DMD had in their bodies. Dystrophin levels increased from an average of 0.6% of normal levels at the beginning of the trial to an average of 5.9% of normal levels by the end of the trial. Every child who took Viltepso had an increase in their dystrophin levels.*

Note: This trial only included male children ages 4 years to 9 years old. And Viltepso’s other clinical trial, which is ongoing at this time, also only includes male children. The drug hasn’t been studied in female children or in adults. So, it’s not known if Viltepso may have similar safety and effectiveness in these groups.

* In this trial, Viltepso wasn’t compared with other medications or a placebo. A placebo is a treatment with no active drug.

Viltepso and children

Viltepso is approved for use in children ages 4 years to 17 years old. And the drug has been shown in clinical trials to be a safe and effective medication for people with certain types of DMD.

In fact, Viltepso has been studied in two clinical trials. The first trial included male children ages 4 years to 9 years old, and the second trial included male children ages 5 years to 17 years old.

Viltepso is approved to treat Duchenne muscular dystrophy (DMD) in people who have a certain gene mutation.* It may be used by itself for this purpose. But in many cases, Viltepso is taken with a steroid medication to help treat DMD. And in an ongoing clinical trial of Viltepso, children continue to take their steroid medication during their treatment with Viltepso.

Steroid medication is a common treatment for DMD. Steroids may slow down the progression of the disease. And they can increase muscle strength. Examples of steroid medications that may be taken to treat DMD include prednisone and deflazacort (Emflaza).

If you take a steroid to treat DMD, your doctor may recommend that you continue taking your steroid during your Viltepso treatment. Be sure to talk with your doctor about the best treatments for you.

* A gene mutation is an abnormal change in a gene. Viltepso is approved for use in people with DMD who are missing a part of their DMD gene called exon 53. See the “Viltepso uses” section above for details.

There are no known interactions between Viltepso and alcohol. But alcohol may worsen the symptoms of Duchenne muscular dystrophy (DMD), which Viltepso is used to treat.

For example, DMD may cause you to have trouble walking or to fall down often. Alcohol may increase these symptoms and make your condition worse.

Talk with your doctor about a safe amount of alcohol for you to drink while you’re taking Viltepso.

Viltepso isn’t known to interact with other medications. It’s also not known to interact with any supplements or foods.

Different interactions can cause different effects. For instance, some interactions can interfere with how well a drug works. Other interactions can increase side effects or make them more severe.

Viltepso and other medications

At this time, Viltepso isn’t known to interact with other medications.

But it’s still important to talk with your doctor and pharmacist before taking Viltepso. Tell them about all prescription, over-the-counter, and other drugs you take. Also, tell them about any vitamins, herbs, and supplements you use. Sharing this information can help you avoid potential interactions.

If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.

Viltepso and herbs and supplements

There aren’t any herbs or supplements that have been specifically reported to interact with Viltepso. But you should still check with your doctor or pharmacist before using any of these products while taking Viltepso.

Viltepso and foods

There aren’t any foods that have been specifically reported to interact with Viltepso. If you have any questions about eating certain foods while taking Viltepso, talk with your doctor.

Other drugs are available that can treat Duchenne muscular dystrophy (DMD). Some may be a better fit for you than others. If you’re interested in finding an alternative to Viltepso, talk with your doctor. They can tell you about other medications that may work well for you.

Some of the drugs listed here are used off-label to treat these specific conditions. Off-label drug use means using a Food and Drug Administration (FDA)-approved drug for a purpose other than what it’s approved for.

It’s important to note that there are different types of DMD. Your treatment may depend on which parts of your genes are affected. Viltepso is approved for use specifically in people with DMD who are missing a part of their DMD gene called exon 53.* So, not all medications may work to treat your specific form of DMD.

Examples of other drugs that may be used to treat DMD include:

Be sure to talk with your doctor about the best treatment plan for your condition.

* See the “Viltepso uses” section above for details.

You should take Viltepso according to your doctor’s or healthcare provider’s instructions.

Viltepso is given by a healthcare provider as an intravenous infusion. This is an injection that’s given over time into a vein in your arm. Viltepso infusions last for about 1 hour.

When it’s given

Viltepso is administered once weekly. Infusions will be given in your doctor’s or healthcare provider’s office.

To help make sure that you don’t miss a dose of Viltepso, try using a medication reminder. This can include setting an alarm or timer on your phone or downloading a reminder app.

Viltepso is approved to treat Duchenne muscular dystrophy (DMD) in people who have a certain gene mutation. A gene mutation is an abnormal change in a gene. DMD can be caused by different types of gene mutations.

Genes are made up of small parts called exons. Exons fit together like puzzle pieces to form a gene. But if one exon is missing, your gene won’t properly fit together. This means that the gene may not function correctly.

Viltepso is approved for use in people with DMD who are missing exon 53. When exon 53 is missing from your DMD gene, your body doesn’t properly produce a protein called dystrophin. Dystrophin allows you to move and flex your muscles. Without dystrophin, symptoms of DMD develop, including trouble walking and muscle weakness.

Viltepso works to allow your body to “skip” over the missing exon 53 so that the rest of your DMD gene can fit together. This helps your body produce dystrophin. The dystrophin protein that’s produced with Viltepso treatment is shorter than usual, but it can still help with muscle movement.

Note: Viltepso doesn’t work to treat all forms of DMD. It only works to treat DMD that may respond to “skipping” of exon 53. There are other genetic changes that may also cause DMD, such as changes that affect a different part of your DMD gene called exon 51. If you have a genetic change other than a missing exon 53, your doctor may recommend a drug other than Viltepso for you.

How long does it take to work?

Viltepso begins working to increase dystrophin in your body after your first infusion. But it may take more time for you to notice a change in your muscles.

A clinical trial showed that after 25 weeks of treatment, dystrophin levels increased from an average of 0.6% of normal levels to an average of 5.9% of normal levels. Also, every child in the trial who was taking Viltepso experienced an increase in their dystrophin levels.

If you have questions about how long Viltepso takes to work, talk with your doctor or pharmacist.

It’s not known if Viltepso is safe to use during pregnancy. Currently, there are no human or animal data to determine if Viltepso may be safe to use during pregnancy. Viltepso also hasn’t been studied in females at this time.

If you’re pregnant or planning to become pregnant, talk with your doctor before starting Viltepso. They may recommend a different medication to treat your Duchenne muscular dystrophy.

It’s not known if Viltepso is safe to take during pregnancy. If you’re sexually active and you or your partner can become pregnant, talk with your doctor about your birth control needs while you’re using Viltepso.

For more information about taking Viltepso during pregnancy, see the “Viltepso and pregnancy” section above.

It’s not known if Viltepso is safe to take while breastfeeding. There are no human or animal data on whether Viltepso may affect breastfeeding. It’s also not known whether the drug passes into breast milk. Viltepso hasn’t been studied in females at this time.

If you’re breastfeeding, talk with your doctor before you start taking Viltepso. They can help you determine the best way to feed your baby.

Here are answers to some frequently asked questions about Viltepso.

Does Viltepso cure Duchenne muscular dystrophy?

No, Viltepso doesn’t cure Duchenne muscular dystrophy (DMD). At this time, there’s no cure for DMD. But treatments such as Viltepso can help prevent DMD from getting worse. Talk with your doctor about the best treatment option for you.

If my child or I have kidney problems, can Viltepso be taken?

Most likely. If you or your child have kidney problems, be sure to talk with your doctor before starting Viltepso treatment. To check how well your kidneys are working, your doctor may do blood tests before you start Viltepso. They will also use blood or urine tests to monitor your kidneys throughout your Viltepso treatment.

It’s possible that Viltepso may cause kidney problems or cause existing kidney problems to get worse. In clinical trials of Viltepso, kidney problems weren’t reported as a side effect. But other drugs in the same class* as Viltepso can cause kidney problems. For this reason, monitoring of kidney function is recommended during Viltepso treatment.

Examples of these types of drugs that can cause kidney problems include inotersen (Tegsedi) and nusinersen (Spinraza).

Talk with your doctor about the specific kidney problems that you or your child have before starting Viltepso. They can help determine if Viltepso is a safe option for your treatment.

* A class of drugs is a group of medications that work in a similar way. Viltepso belongs to a class of drugs called antisense oligonucleotides.

Will lab tests need to be done while I’m using Viltepso?

Yes. In most cases, you’ll have lab tests before you start taking Viltepso, as well as during your treatment.

You’ll likely have kidney function tests before and during your Viltepso treatment. Kidney function tests may be a blood test or a urine test. Monitoring of kidney function is recommended during Viltepso treatment because it’s possible that Viltepso may cause kidney problems. In clinical trials of Viltepso, kidney problems weren’t reported as a side effect. But other drugs in the same class* as Viltepso can cause kidney problems.

Before you start taking Viltepso, your doctor will discuss which lab tests you’ll likely have during your treatment. If you have any questions about which lab tests to expect, talk with your doctor.

* A class of drugs is a group of medications that work in a similar way. See the “If my child or I have kidney problems, can Viltepso be taken?” question just above for more details.

Do other treatments for DMD need to be used with Viltepso?

Usually, yes. Viltepso may be used by itself to treat DMD. But in many cases, it’s taken with a steroid medication for DMD treatment. And in an ongoing clinical trial of Viltepso, children continue to take their steroid medication during their treatment with Viltepso.

Steroid medication is a common treatment for DMD. Steroids may slow down the progression of the disease. And they can increase muscle strength. Examples of steroid medications that may be taken to treat DMD include prednisone and deflazacort (Emflaza).

If you take a steroid to treat DMD, your doctor may recommend that you continue taking your steroid during your Viltepso treatment. Be sure to talk with your doctor about the best treatments for you.

Is Viltepso a treatment option for all types of DMD?

No, Viltepso isn’t an option for all forms of DMD. Because of how Viltepso works in your body, it can only work to treat DMD in people who have certain genetic changes.

Specifically, Viltepso is approved for use in people with DMD who are missing part of their DMD gene called exon 53. Viltepso only works to treat DMD that may respond to “skipping” of exon 53. See the “How Viltepso works” section above for more information about how the drug works in your body.

There are other genetic changes that may also cause DMD, such as changes that affect a different part of the DMD gene called exon 51. If you have a genetic change other than a missing exon 53, your doctor may recommend a drug other than Viltepso for you.

Before taking Viltepso, talk with your doctor about your health history. Viltepso may not be right for you if you have certain medical conditions or other factors affecting your health. These include:

  • Kidney problems. Drugs such as Viltepso may cause kidney problems. If you already have a kidney condition, such as chronic kidney disease, you may be at increased risk for your kidney problems getting worse. Talk with your doctor about any kidney problems that you may have. They can determine if it’s safe for you to take Viltepso.
  • Allergic reaction. If you’ve had an allergic reaction to Viltepso or any of its ingredients, you shouldn’t take this drug. Ask your doctor about which other medications are better options for you.
  • Pregnancy. It’s not known if Viltepso is safe to take during pregnancy. At this time, Viltepso hasn’t been studied in females. For more information, see the “Viltepso and pregnancy” section above.
  • Breastfeeding. It’s not known if Viltepso is safe to take while breastfeeding. At this time, Viltepso hasn’t been studied in females. For more information, see the “Viltepso and breastfeeding” section above.

Note: For more information about the potential negative effects of Viltepso, see the “Viltepso side effects” section above.

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.