Vyvgart (efgartigimod alfa-fcab) is a prescription drug that’s used to treat myasthenia gravis (MG). Vyvgart comes as a liquid solution that’s given as an intravenous (IV) infusion.

Doctors prescribe Vyvgart for adults with MG who have:

  • weakness in the eye muscles as well as in other muscles in the arms, legs, or chest (generalized MG)
  • antibodies that block or damage a protein on the muscle cell surface called the acetylcholine receptor

To learn more about Vyvgart’s uses, see the “What is Vyvgart used for?” section below.

Vyvgart basics

Vyvgart is a biologic drug. A biologic is made from parts of living organisms. Vyvgart contains the active ingredient efgartigimod alfa-fcab*. (An active ingredient is what makes a drug work.)

Vyvgart isn’t available in a biosimilar form. (Biosimilars are like generic drugs. But unlike generics, which are made for nonbiologic drugs, biosimilars are made for biologic drugs.) It comes only as the brand-name drug Vyvgart.

Vyvgart is a neonatal Fc receptor blocker. It’s available as an IV infusion (an injection into a vein given over a longer period of time).

A similar drug is also available from the manufacturer. It’s called Vyvgart Hytrulo. It contains the active ingredients efgartigimod alfa and hyaluronidase-qvfc*. Vyvgart Hytrulo comes as a liquid solution for injection under the skin. Both Vyvgart infusions and Vyvgart Hytrulo injections are given by a healthcare professional.

This article focuses on Vyvgart, but if you’d like to learn more about Vyvgart Hytrulo, talk with your doctor or pharmacist.

* The reason “-fcab” and “-qvfc” appear at the end of the drug names is to show that they’re distinct from similar medications that may be created in the future.

Doctors prescribe Vyvgart for adults with myasthenia gravis (MG) who have:

  • weakness in the eye muscles as well as in other muscles in the arms, legs, or chest (generalized MG)
  • antibodies that block or damage the acetylcholine receptor (AChR)

MG is a kind of autoimmune disease. If you have an autoimmune disease, antibodies in your immune system mistakenly cause damage to your own cells.

The AChR is a receptor (a type of protein) on the surface of muscle cells. It’s important for nerve-muscle communication. When antibodies block or damage this receptor, communication between nerve cells and skeletal muscle cells is decreased. This causes weakness in the muscles you use to move your body.

Symptoms of MG can include:

  • weakness in your arms or legs
  • muscle fatigue
  • difficulty breathing, swallowing, or talking
  • drooping eyelids
  • changes in facial expressions

Vyvgart treats MG by removing certain antibodies from your body. This helps to protect the AChR and improves communication between nerve cells and skeletal muscle cells. To learn more about how Vyvgart works, see the manufacturer’s website.

Costs of prescription drugs can vary depending on many factors. These factors include what your insurance plan covers and where you receive your infusions.

If you have questions about how to pay for your prescription, talk with your doctor. You can also look at the drug manufacturer’s website to learn more about a patient support program called My Vyvgart Path. If you have private insurance, you may be eligible for the Vyvgart Co-Pay Program.

Lastly, you can also check out this article to learn more about saving money on prescriptions.

Like most drugs, Vyvgart may cause mild or serious side effects. The lists below describe some of the more common side effects that Vyvgart may cause. These lists don’t include all possible side effects.

Keep in mind that side effects of a drug can depend on:

  • your age
  • other health conditions you have
  • other medications you take

Your doctor or pharmacist can tell you more about the potential side effects of Vyvgart. They can also suggest ways to help reduce side effects.

Mild side effects

Here’s a list of some of the mild side effects that Vyvgart can cause. To learn about other mild side effects, talk with your doctor or pharmacist, or read Vyvgart’s prescribing information.

Mild side effects of Vyvgart that have been reported include:

Mild side effects of many drugs may go away within a few days to a couple of weeks. But if they become bothersome, talk with your doctor or pharmacist.

* To learn more about this side effect, see the “Allergic reaction” section below.

Serious side effects

Serious side effects from Vyvgart can occur, but they aren’t common. If you have serious side effects from Vyvgart, call your doctor right away. But if you think you’re having a medical emergency, you should call 911 or your local emergency number.

Serious side effects of Vyvgart that have been reported include:

* To learn more about this side effect, see the “Allergic reaction” section below.

Allergic reaction

Some people may have an allergic reaction to Vyvgart. These reactions were rare in studies of Vyvgart, and most instances were mild. However, serious reactions can still occur.

Symptoms of a mild allergic reaction can include:

A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include swelling under your skin, usually in your eyelids, lips, hands, or feet. They can also include swelling of your tongue, mouth, or throat, which can cause trouble breathing.

Call your doctor right away if you have an allergic reaction to Vyvgart. But if you think you’re having a medical emergency, call 911 or your local emergency number.

Your doctor will recommend the dosage of Vyvgart that’s right for you. Below are commonly prescribed dosages, but the dosage you receive will be determined by your doctor.

Form and strength

Vyvgart comes as a liquid solution for intravenous (IV) infusion (an injection into your vein given over time).

Each single-use vial contains 400 milligrams (mg) of drug in 20 milliliters (mL) of liquid solution. Its strength is 20 milligrams per milliliter (mg/mL).

Recommended dosage

For treating myasthenia gravis, your doctor will likely recommend that you receive at least one 4-week treatment cycle of Vyvgart.

Your dose depends on your body weight. The usual dose of Vyvgart is 10 mg for each kilogram (kg) of body weight, up to a maximum dose of 1,200 mg. For reference, 1 kg is approximately 2.2 pounds (lb). As an example, a person weighing 80 kg (about 176 lb) will receive an 800-mg dose of Vyvgart.

Each week, you’ll receive one Vyvgart dose, for a total of four doses.

Your doctor will recommend whether you’ll need more treatment cycles.

Questions about Vyvgart’s dosing

Below are some common questions about Vyvgart’s dosing.

  • What if I miss a dose of Vyvgart? If you miss an appointment to receive Vyvgart, call your doctor’s office or the infusion center as soon as possible. They’ll reschedule your appointment if you’re still within 3 days of the original appointment. If more than 3 days have passed since your appointment, they’ll likely recommend that you resume your treatment at the next scheduled appointment.
  • Will I need to receive Vyvgart long term? No, Vyvgart isn’t usually prescribed as a long-term treatment. It’s usually given in 4-week cycles. But these treatment cycles may be repeated as needed. In studies, doctors prescribed a second treatment cycle an average of 94 days after the first treatment cycle was completed.
  • How long does Vyvgart take to work? Vyvgart begins working with your first infusion. In studies, some people reported a reduction in symptoms after 1 week of treatment. But for many people, the full benefit was noticed after 4 weeks of treatment. (Some examples of symptoms included in the study are difficulty chewing, rising from a chair, and brushing teeth.)

Find answers to some commonly asked questions about Vyvgart.

Is Vyvgart similar to Soliris or Ultomiris?

Yes, in some ways, Vyvgart is similar to Soliris (eculizumab) and Ultomiris (ravulizumab-cwvz).

Each can be prescribed to adults to treat myasthenia gravis (MG) that affects the eye muscles as well as other muscles in the arms, legs, or chest (generalized MG). And they’re all prescribed to adults who have antibodies to the acetylcholine receptor.

Vyvgart, Soliris, and Ultomiris all work to decrease the activity of the immune system, but they do it in different ways. Vyvgart affects antibodies, while Soliris and Ultomiris affect a protein called complement 5.

Each drug is administered by a healthcare professional. They also share some similar side effects, such as headache and respiratory infection.

If you’d like to learn more about how other treatments for MG compare with Vyvgart, talk with your doctor or pharmacist.

Does Vyvgart cause weight gain?

No, Vyvgart isn’t known to cause weight gain. This side effect wasn’t reported in studies of Vyvgart.

But weight gain can be a problem for some people with MG. This is because weakness caused by the condition can limit physical activity. In addition, some other treatments for MG can cause weight gain, including corticosteroids such as prednisone (Rayos).

If you have concerns about your weight or want to know whether medications you’re taking may cause weight gain, talk with your doctor.

How does Vyvgart work?

With MG, antibodies in your immune system mistakenly block or damage certain receptors (a kind of protein) on the muscle cell surface. These receptors are important for nerve-muscle communication. When these receptors are blocked or damaged, you experience muscle weakness.

Vyvgart lowers the levels of these antibodies. It does this by blocking a protein that usually protects antibodies. These antibodies are then removed from the body.

With Vyvgart treatment, fewer antibodies are present to block or damage the receptor on the muscle cell surface. This means that nerve-muscle communication improves.

To learn more about MG and how Vyvgart works, see the “What is Vyvgart used for?” section. You can also talk with your doctor or pharmacist.

Your doctor will explain how Vyvgart will be given to you. They’ll also explain how much you’ll be given and how often.

Receiving Vyvgart

Vyvgart comes as a liquid solution in a vial. A healthcare professional will prepare Vyvgart and give you your dose as an intravenous (IV) infusion (an injection into your vein given over time). The infusion will take about 1 hour, but you’ll stay a little longer to be monitored for any side effects after the infusion. This all takes place at your doctor’s office, hospital, or infusion center.

Questions about taking Vyvgart

Below are some common questions about taking Vyvgart.

  • Should I take Vyvgart with food? Food does not affect Vyvgart. You can go to your appointment regardless of whether you’ve eaten recently. However, it’s important to remember you’ll be receiving an IV. It’s easier for the healthcare professional to start your IV if you’re well hydrated.
  • How long will it take to receive my Vyvgart infusion? Vyvgart infusions usually last about 1 hour. Consider bringing a book, podcast, or game to pass the time during your infusion. A healthcare professional will be close by to monitor your health and vital signs during the infusion so that you can relax.

Before beginning treatment with Vyvgart, you’ll want to discuss a few things with your doctor. This includes discussing any other medications you take and health conditions you have. This information allows your doctor to check for interactions with Vyvgart before prescribing it for you.


Taking a medication with certain vaccines, foods, and other things can affect how the medication works. These effects are called interactions.

Before taking Vyvgart, be sure to tell your doctor about all medications you take, including prescription and over-the-counter types. Also, describe any vitamins, herbs, or supplements you use. Your doctor or pharmacist can tell you about any interactions these items may cause with Vyvgart.

For information about drug-condition interactions, see the “Warnings” section below.

Interactions with drugs or supplements

Vyvgart can interact with several types of drug groups. These groups of drugs include:

This list doesn’t contain all types of drugs that may interact with Vyvgart. Your doctor or pharmacist can tell you more about these interactions and any others that may occur with Vyvgart.

Other interactions

You should not receive a live vaccine during your treatment with Vyvgart. (Live vaccines contain a weakened form of the virus or bacterium they protect against.)

Receiving a live vaccine during treatment with Vyvgart could cause you to become sick from the virus contained in the vaccine.

Examples of live vaccines include:

Before starting treatment with Vivgart, ask your doctor if you’re due for any vaccinations. Your doctor may recommend that you get them before you begin treatment.


Vyvgart can sometimes cause harmful effects in people who have certain conditions. This is known as a drug-condition interaction. Other factors may also affect whether Vyvgart is a good treatment option for you.

Talk with your doctor about your health history before you take Vyvgart. Factors to consider include those described below.

Weakened immune system. Treatment with Vyvgart can increase your risk of infection. If you already have a weakened immune system, your risk of infection may be higher.

Allergic reaction. If you’ve had an allergic reaction to Vyvgart or any of its ingredients, your doctor will likely not prescribe Vyvgart. Ask them about other medications that might be better options.

Vyvgart and alcohol

Vyvgart isn’t known to interact with alcohol.

If you have questions about consuming alcohol during Vyvgart treatment, talk with your doctor or pharmacist.

Pregnancy and breastfeeding

It’s not known whether it’s safe to receive treatment with Vyvgart if you’re pregnant or breastfeeding.

Talk with your doctor to learn more about the risks and benefits of receiving Vyvgart for myasthenia gravis during pregnancy or while breastfeeding.

If you have questions about taking Vyvgart, talk with your doctor or pharmacist. Questions you may want to ask include:

  • How does Vyvgart compare with other treatments for myasthenia gravis?
  • How will we determine whether I need future treatment cycles with Vyvgart?
  • If I develop an infection while taking Vyvgart, will I need to pause treatment?
  • Do any health conditions I have increase my risk of side effects from Vyvgart?

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Disclaimer: Healthline 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 another 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.