Pronunciation: EF-gar-TIG-i-mod AL-fa
Generic name: efgartigimod alfa
Brand name: Vyvgart
Dosage form: injection for intravenous infusion
Drug class: Immune globulins

Medically reviewed by Carmen Pope, BPharm. Last updated on Nov 29, 2024.

What is efgartigimod alfa?

Efgartigimod alfa (brand name Vyvgart) is used to treat generalized myasthenia gravis (gMG) in adults who are anti-acetylcholine receptor (AChR) antibody-positive.

• Efgartigimod alfa (Vyvgart) is given as an intravenous infusion (an infusion into the vein) over one hour.
• Efgartigimod alfa + hyaluronidase (Vyvgart Hytrulo) is a formulation of efgartigimod alfa that contains hyaluronidase and is given by subcutaneous injection (under the skin) over 30 to 90 seconds (see What is the difference between Vyvgart and Vyvgart Hytrulo? for more information).
• Both efgartigimod alfa and efgartigimod alfa + hyaluronidase are given by a healthcare provider.

Efgartigimod alfa's mechanism of action involves attaching to and blocking a protein called neonatal Fc receptor (FcRn) which binds circulating IgG antibodies. When antibodies, including harmful ones, attach to FcRN, their time in the body is extended but those that remain unattached are removed by the body. Harmful IgG antibodies are thought to play a role in CIDP and gMG. efgartigimod alfa is a fragment of an IgG antibody that keeps some FcRn receptors occupied, so more IgG antibodies, including harmful ones, remain unattached and are removed from the body.

Efgartigimod alfa is a biologic drug made from living cells and belongs to the drug class neonatal Fc receptor (FcRn) inhibitors. It may also be called an immunomodulator.

Efgartigimod alfa first gained FDA approval on December 17, 2021, for gMG, under the brand name Vyvgart. Efgartigimod alfa + hyaluronidase first gained FDA approval on June 20, 2023, for gMG, and approval was extended on June 21, 2024, to cover chronic inflammatory demyelinating polyneuropathy (CIDP). There is no efgartigimod alfa generic or biosimilar.

What is efgartigimod alfa used for?

Efgartigimod alfa (Vyvgart) is used to treat gMG in adults who are anti-acetylcholine receptor (AChR) antibody positive.

Efgartigimod alfa + hyaluronidase (Vyvgart Hytrulo) is used to treat adults with gMG who are anti-acetylcholine receptor (AChR) antibody-positive or to treat CIDP.

Efgartigimod alfa side effects

The most common side effects of efgartigimod alfa are:

• respiratory tract infections
• headache
• urinary tract infections
• red, pain, itching, bruising, or swelling at the site where the injection was given.

Serious side effects and warnings

Efgartigimod alfa can cause the following serious side effects.

Efgartigimod alfa can increase your risk of infection and should not be administered if you currently have an infection. The most common infections for efgartigimod alfa-treated patients were 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 efgartigimod alfa. 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 efgartigimod alfa. 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. Efgartigimod alfa 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.

Related/similar drugs

Before receiving this medicine

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

To make sure efgartigimod alfa 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 efgartigimod alfa
• are pregnant or plan to become pregnant
• are breastfeeding or plan to breastfeed.

How is efgartigimod alfa administered?

Efgartigimod alfa (brand name Vyvgart) is administered intravenously (into a vein) by a healthcare provider in their clinic.

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

Efgartigimod alfa dosage

Dosage of efgartigimod alfa for gMG in adults

• Efgartigimod alfa (Vyvgart) 10 mg/kg administered as an IV infusion over 1 hour 1 time 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.

What happens if I miss a dose?

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

What happens if I overdose?

An overdose is unlikely because efgartigimod alfa is administered by a healthcare provider.

What should I avoid while receiving efgartigimod alfa?

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 efgartigimod alfa?

Efgartigimod alfa 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 efgartigimod alfa with other medications that bind to the human neonatal Fc receptor (FcRn) (such as immunoglobulin products, monoclonal antibodies, or antibody derivates containing the human Fc domain of the IgG subclass) because it may reduce the effectiveness of these medications.

Efgartigimod alfa ingredients

Efgartigimod alfa is only available under the brand name Vyvgart. There is no Vyvgart generic.

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.

Who makes efgartigimod alfa?

Argenx BV manufactures efgartigimod alfa under the brand name Vyvgart.

Efgartigimod alfa Biosimilars

Biosimilar and interchangeable products are biological products that are highly similar to and have no clinically meaningful differences from the reference product.

Reference products

These are biological products that have already been approved by the FDA, against which biosimilar products are compared. There is 1 for efgartigimod alfa.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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