Pronunciation: VIV-gart
Generic name: efgartigimod alfa
Other brand names of efgartigimod alfa include: Vyvgart, Vyvgart Hytrulo
Dosage form: single-dose vial for injection (400 mg/20 mL)
Drug class: Immune globulins

Medically reviewed by Carmen Pope, Senior Medical Editor, B. Pharm. Last updated on May 13, 2026.

What is Vyvgart?

Vyvgart for IV infusion is used to treat generalized myasthenia gravis (gMG) in adults, a rare autoimmune disease where harmful antibodies disrupt nerve-muscle communication, causing muscle weakness. It is given as a one-hour IV infusion once a week for 4 weeks. 

Vyvgart (efgartigimod alfa) is a first-in-class neonatal Fc receptor blocker developed by argenx that works by binding to the FcRn (neonatal Fc receptor) to increase the rate at which circulating IgG antibodies, including the disease-causing autoantibodies driving myasthenia gravis, are broken down. In the Phase 3 ADAPT trial, 68% of patients assigned to Vyvgart met a two-point or greater reduction in the MG Activities of daily living (MG-ADL) score sustained for at least 4 consecutive weeks, versus 30% on placebo. Common side effects include respiratory infections, headache, and urinary tract infections.

Vyvgart (efgartigimod alfa) received FDA approval on December 17, 2021, for the treatment of gMG. There is no generic.

• Vyvgart Hytrulo is a subcutaneous formulation of Vyvgart that can be administered quickly and self-administered. 
• This guide covers Vyvgart for IV infusion only.

Side effects

Common side effects

The most common side effects of Vyvgart are:

• Respiratory tract infections
• Headache
• Urinary tract infections.

Serious side effects and warnings

Vyvgart can cause the following serious side effects:

• An increased risk of infection. Vyvgart should not be administered if you currently have an infection. The most common infections seen in Vyvgart-treated patients are urinary tract and respiratory tract infections. Call your healthcare provider if you develop signs or symptoms of an infection such as fever, chills, frequent and/or painful urination, cough, pain, and blockage of nasal passages/sinus, wheezing, shortness of breath, fatigue, sore throat, excess phlegm, nasal discharge, back pain, or chest pain.
• Allergic reactions (hypersensitivity reactions). These have occurred in some patients treated with Vyvgart. Most were mild or moderate and occurred within one hour to three weeks of medicine administration. Symptoms included rashes, swelling under the skin, and trouble breathing. Hives and serious allergic reactions, such as trouble breathing and a decrease in blood pressure leading to fainting, have also been reported in patients treated with Vyvgart. Your doctor will monitor you during your infusion for hypersensitivity reactions. Get emergency medical help if you have signs of an allergic reaction, such as hives, difficulty breathing, or swelling of your face, lips, tongue, or throat.
• Infusion-related reactions. Vyvgart can cause infusion-related reactions. The most frequent
  symptoms and signs reported were high blood pressure, chills, shivering, and chest, abdominal, and back pain.

This is not a complete list of side effects, and others may occur. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Before receiving this medicine

Do not receive Vyvgart if you are allergic to efgartigimod alfa, Vyvgart, Vyvgart Hytrulo, or any of the inactive ingredients in the preparation. Vyvgart can cause serious allergic reactions and a decrease in blood pressure, leading to fainting.

To make sure Vyvgart is safe for you, tell your doctor if you:

• Have any allergies
• Currently have an infection or have had any infections recently
• Have received or are scheduled to receive a vaccine (immunization). You should have received all your age-appropriate immunizations before starting Vyvgart
• Are pregnant or plan to become pregnant
• Are breastfeeding or plan to breastfeed.

How does Vyvgart work?

Vyvgart (efgartigimod alfa) works by attaching to and blocking a protein called neonatal Fc receptor (FcRn), which binds circulating IgG antibodies. By occupying these receptors, Vyvgart prevents harmful antibodies from binding, allowing the body to naturally remove them faster. This helps conditions such as gMG, where harmful antibodies damage nerves and muscles. This mechanism demonstrates selectivity for IgG antibodies while preserving other immunoglobulin classes that do not utilize the FcRn recycling pathway.

Vyvgart (efgartigimod alfa) belongs to the drug class called neonatal Fc receptor blockers. 

How is Vyvgart administered?

Vyvgart is administered intravenously (into a vein) by a healthcare provider in a clinic.

• Vyvgart takes about an hour to be administered.
• After administration, you will be monitored for hypersensitivity reactions for 30 minutes.

Dosing information

Dose of Vyvgart for gMG in adults

• 10 mg/kg administered intravenously over 1 hour.
• Administer once a week for 4 weeks.

Subsequent treatment cycles may be administered based on clinical evaluation.

• It is unknown if it is safe to administer a subsequent treatment cycle within 50 days of the first treatment cycle.

Related/similar drugs

What happens if I miss a dose?

If you miss a dose, ring your healthcare provider to reschedule. The infusion may be administered up to 3 days after the scheduled time. Resume the original dosing schedule until the treatment cycle is completed.

What should I avoid while receiving Vyvgart?

You should avoid receiving live vaccines, such as chickenpox, measles, or mumps, while you are being treated with this medicine.

What other drugs will affect Vyvgart?

Vyvgart may interact with other prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all other medicines you use, and when you start, stop, or change a dose of any medicine.

Care should be taken when using Vyvgart with other medications that bind to the human neonatal Fc receptor (FcRn) (such as immunoglobulin products, monoclonal antibodies, or antibody derivatives containing the human Fc domain of the IgG subclass) because it may reduce the effectiveness of these medications.

Ingredients

Active ingredients: efgartigimod alfa 20 mg/mL

Inactive ingredients: Arginine hydrochloride, polysorbate 80, sodium chloride, sodium phosphate, dibasic, anhydrous, sodium phosphate, monobasic, monohydrate, and water for injection.

Vyvgart is available as a 400 mg in 20 mL (20 mg/mL) injection in a single-dose vial.

Manufacturer

Vyvgart is made by Argenx BV, Industriepark 7, 9052 Zwijnaarde, Belgium, and distributed by Argenx US, Inc., 33 Arch Street, Boston, MA 02110.

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Further information

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