Efgartigimod alfa and hyaluronidase

Pronunciation: EF-gar-TIG-i-mod AL-fa and HYE-al-ure-ON-i-dase
Generic name: efgartigimod alfa and hyaluronidase-qvfc
Brand name: Vyvgart Hytrulo
Dosage form: single-dose prefilled syringe for subcutaneous injection (efgartigimod alfa 1000 mg/hyaluronidase 10,000 units), single-dose vial for subcutaneous injection (efgartigimod alfa 1008 mg/ hyaluronidase 11,200 units)
Drug class: Immune globulins

Medically reviewed by Carmen Pope, BPharm. Last updated on Jul 8, 2025.

What is efgartigimod alfa and hyaluronidase?

Efgartigimod alfa and hyaluronidase (Vyvgart Hytrulo) is an injection used to treat generalized myasthenia gravis (gMG) in adults who are anti-acetylcholine receptor (AChR) antibody-positive, and for adults with chronic inflammatory demyelinating polyneuropathy (CIDP). It is given subcutaneously (under the skin) once a week and can be self-administered or administered by a caregiver or healthcare provider. 

Efgartigimod alfa works by blocking the neonatal Fc receptor (FcRn), a protein that normally extends the lifespan of antibodies in the body. By blocking these receptors, harmful IgG antibodies remain unattached and are naturally removed. This mechanism helps treat CIDP and gMG, conditions where harmful antibodies cause disease. Efgartigimod alfa belongs to the drug class called neonatal Fc receptor (FcRn) inhibitors. The hyaluronidase component allows this medicine to be given subcutaneously. Hyaluronidase is an enzyme that temporarily increases the permeability of subcutaneous tissue by depolymerizing a critical component of the skin's structure called hyaluronan, allowing larger injection quantities to be given subcutaneously. The integrity of the subcutaneous tissue is restored within 24 to 48 hours.

Efgartigimod alfa + hyaluronidase (Vyvgart Hytrulo) 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 generic or biosimilar.

• Vyvgart is an IV formulation of efgartigimod alfa given intravenously by a healthcare provider for gMG.

Side effects

The most common side effects of efgartigimod alfa and hyaluronidase are:

• respiratory tract infections
• headache
• urinary tract infections
• infusion site reactions.

Serious side effects and warnings

Efgartigimod alfa + hyaluronidase can cause the following serious side effects.

• An increased risk of infection. This medicine 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 and hyaluronidase. 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 + hyaluronidase. 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. Infusion-related reactions have been reported with efgartigimod alfa. 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 + hyaluronidase if you are allergic to efgartigimod alfa, hyaluronidase, 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 + hyaluronidase 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.

Pregnancy

It is not known whether efgartigimod alfa + hyaluronidase will harm your unborn baby.

Pregnancy Exposure Registry. There is a pregnancy exposure registry for women who use efgartigimod alfa + hyaluronidase during pregnancy. The purpose of this registry is to collect information about your health and your baby. Your healthcare provider can enroll you in this registry. You may also enroll yourself or get more information about the registry by calling 1-855-272-6524 or going to https://www.Vyvgartpregnancy.com

Breastfeeding

It is not known if efgartigimod alfa + hyaluronidase passes into your breast milk.  

How is efgartigimod alfa + hyaluronidase administered?

Administer efgartigimod alfa + hyaluronidase exactly as your healthcare provider tells you to.

• Efgartigimod alfa + hyaluronidase is injected under your skin (subcutaneously) only. Do not inject into a vein (intravenously).
• It is administered under the skin of your abdominal area, but not within 2 inches of your navel.
• For gMG, efgartigimod alfa + hyaluronidase is injected 1 time a week for 4 weeks (treatment cycle). Your healthcare provider will tell you when to administer your future treatment cycles.
• For CIDP, efgartigimod alfa + hyaluronidase is injected 1 time a week.

Efgartigimod alfa + hyaluronidase comes in a single-dose prefilled syringe and single-dose vial.

• Only a healthcare provider should inject efgartigimod alfa + hyaluronidase using the single-dose vial.
• If you are prescribed the efgartigimod alfa + hyaluronidase prefilled syringe, you or your caregiver should receive training on the right way to prepare and inject the prefilled syringe.
• Do not try to inject efgartigimod alfa + hyaluronidase prefilled syringe until you have been shown the right way by a healthcare provider.
• See the detailed Instructions for Use that comes with the efgartigimod alfa + hyaluronidase prefilled syringe.
• Monitor for signs and symptoms of an allergic reaction for at least 30 minutes after administration.

Efgartigimod alfa + hyaluronidase is given as a slow and steady injection.

• It will take 20 to 30 seconds to inject all of the medicine when you use the prefilled syringe.
• After administration, you should monitor yourself for hypersensitivity reactions for 30 minutes

Dosing information

Dose of efgartigimod alfa + hyaluronidase for gMG in adults

• Prefilled syringe: 1000 mg/10,000 units SC over 20 to 30 seconds 1 time a week for 4 weeks.
• Vial (Healthcare Provider only): 1008 mg/11,200 units SC over 30 to 90 seconds 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.

Dose of efgartigimod alfa + hyaluronidase for CIDP in adults

• Prefilled syringe: 1000 mg/10,000 units SC over 20 to 30 seconds 1 time a week.
• Vial (Healthcare Provider only): 1008 mg / 11,200 units SC over 30 to 90 seconds 1 time a week.

What happens if I miss a dose?

If you miss a dose, ring your healthcare provider to reschedule. The 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 + hyaluronidase 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 + hyaluronidase 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 + hyaluronidase 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.

Storage

Refrigerator

Store Vyvgart Hytrulo in the refrigerator between 36°F to 46°F (2°C to 8°C).

Only warm Vyvgart Hytrulo just before use by letting it sit on a flat surface for at least 30 minutes for the prefilled syringe and 15 minutes for the vial. Do not warm Vyvgart Hytrulo any other way (eg, with an external heat source).

• Store Vyvgart Hytrulo in the original carton to protect it from light until you are ready to use it.
• Do not freeze or shake.
• Do not use Vyvgart Hytrulo past the expiration date.
• Vygart Hytrulo is for one-time use only (single-dose).

Remove from the refrigerator only the dose you are preparing to inject. Future doses should remain refrigerated until ready to use.

Room temperature

If needed, Vyvgart Hytrulo may be stored at room temperature. Record the date you removed Vyvgart Hytrulo from the refrigerator.

• Single-dose prefilled syringe may be stored at room temperature (up to 86°F (30°C)) for up to 30 days. When removed from the refrigerator and brought to room temperature, Vyvgart Hytrulo must be used within 30 days or thrown away.
• Single-dose vial may be stored at room temperature (between 68°F to 77°F (20°C to 25°C)) for up to 3 days. When removed from the refrigerator and brought to room temperature,  Vyvgart Hytrulo must be used within 3 days or thrown away.
• Do not put Vyvgart Hytruloback into the refrigerator after it has warmed to room temperature.

Keep  Vyvgart Hytrulo and all medicines out of the reach of children.

Ingredients

Available as Vyvgart Hytrulo 

Active ingredients: efgartigimod alfa and hyaluronidase (human recombinant)

Inactive ingredients:

• single-dose prefilled syringe: arginine hydrochloride, histidine, L-histidine hydrochloride monohydrate,
  methionine, polysorbate 80, sodium chloride, sucrose, and water for injection, USP
• single-dose vial: histidine, L-histidine hydrochloride monohydrate, methionine, polysorbate 20, sodium chloride, sucrose, and water for injection, USP

Vyvgart Hytrulo is available as:

• Single-dose prefilled syringe for injection: 1,000 mg efgartigimod alfa and 10,000 units of hyaluronidase per 5 mL (200 mg/2,000 units per mL)
• Single-dose vial for injection: 1,008 mg efgartigimod alfa and 11,200 units of hyaluronidase per 5.6 mL (180 mg/2,000 units per mL).

Preservative-free.

Manufacturer

Vyvgart Hytrulo (efgartigimod alfa and hyaluronidase-qvfc) is manufactured by:

• argenx BV Industriepark 7, 9052 Zwijnaarde, Belgium, U.S. License No. 2217
• Halozyme, Inc. 12390 El Camino Real, San Diego, CA 92130, U.S. License No. 2187.

It is distributed by argenx US, Inc. 33 Arch Street, Boston, MA 02110.

Efgartigimod alfa/hyaluronidase 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/hyaluronidase.

Further information

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

Medical Disclaimer