Vyvgart

Vyvgart (efgartigimod alfa-fcab) is an intravenous (IV) infusion used to treat generalized myasthenia gravis (gMG) in adults. It can be used whether or not a person tests positive for anti-acetylcholine receptor (AChR) antibodies. gMG is a rare autoimmune disease in which harmful antibodies disrupt communication between nerves and muscles, causing muscle weakness.

Vyvgart is a neonatal Fc receptor (FcRn) blocker. It lowers the levels of IgG antibodies in the blood, including the autoantibodies that drive gMG. It is given as a 1-hour infusion once a week for 4 weeks, which makes up one treatment cycle. Further cycles are given based on how you respond.

In the Phase 3 ADAPT trial, 67.7% of AChR antibody-positive patients treated with Vyvgart had a 2-point or greater reduction in their MG Activities of Daily Living (MG-ADL) score sustained for at least 4 consecutive weeks, compared with 29.7% on placebo. Vyvgart also improved MG-ADL scores in AChR antibody-negative patients. Common side effects include respiratory tract infections, headache, and urinary tract infections.

Vyvgart was first approved by the FDA on December 17, 2021, for adults with AChR antibody-positive gMG. In May 2026, the approval was expanded to include all adults with 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.

Vyvgart was studied in two randomized, double-blind, placebo-controlled trials in adults with gMG who were already on stable standard MG therapy.

*2-point or greater reduction in MG-ADL score for at least 4 consecutive weeks during the first treatment cycle. **3-point or greater reduction in Quantitative Myasthenia Gravis (QMG) score for at least 4 consecutive weeks during the first treatment cycle. MG-ADL measures the effect of gMG on daily activities; QMG measures muscle weakness.

Vyvgart is given by a healthcare provider as an intravenous infusion.

• Your dose is diluted in a 125 mL bag of saline and infused over 1 hour.
• You will be monitored during the infusion and for 1 hour afterward for signs of an allergic reaction.
• Your healthcare provider will check whether you need any vaccines before you start a new treatment cycle.

You should not receive Vyvgart if you have had a serious allergic reaction to efgartigimod alfa products or any of the inactive ingredients in Vyvgart. Reactions have included anaphylaxis and low 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). Your healthcare provider will check whether you need any age-appropriate vaccines before you start a new treatment cycle
• Are pregnant or plan to become pregnant
• Are breastfeeding or plan to breastfeed.

Pregnancy

There are no data on Vyvgart use in pregnancy. Vyvgart may cross the placenta, especially in the third trimester, and may lower the antibodies that normally protect a newborn. If you received Vyvgart while pregnant, tell your baby's healthcare provider before your baby receives any live vaccines. A pregnancy exposure registry monitors outcomes in women exposed to Vyvgart during pregnancy; call 1-855-272-6524 or visit www.vyvgartpregnancy.com.

Breastfeeding

It is not known if Vyvgart passes into breast milk. Talk to your healthcare provider about the benefits and risks of breastfeeding during treatment.

Other groups

• Children: safety and effectiveness have not been established.
• Adults 65 and older: too few were studied to know if they respond differently.
• Kidney problems: no dose change is needed for mild kidney impairment. There is not enough information for moderate or severe impairment.

Vyvgart is a fragment of a human IgG1 antibody that binds to the neonatal Fc receptor (FcRn). FcRn normally protects IgG antibodies from being broken down, which keeps them circulating in the blood for longer. By blocking FcRn, Vyvgart lowers circulating IgG levels, including the autoantibodies that cause gMG. In clinical trials, IgG levels fell during treatment, and anti-AChR and anti-MuSK autoantibody levels followed a similar pattern.

Vyvgart belongs to the drug class called neonatal Fc receptor blockers.

Common side effects

Side effects reported in at least 5% of patients receiving Vyvgart, and more often than with placebo, in Study 1:

In AChR antibody-negative patients (Study 2), nausea was also reported in 7% of patients receiving Vyvgart compared with 5% on placebo.

Serious side effects and warnings

Vyvgart can cause the following serious side effects:

• An increased risk of infection. Vyvgart should not be given if you currently have an infection. The most common infections seen in Vyvgart-treated patients are urinary tract and respiratory tract infections. In clinical trials, more people receiving Vyvgart than placebo had low white blood cell, lymphocyte, and neutrophil counts. Most infections and blood count changes were mild to moderate. 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). Rash, swelling under the skin (angioedema), and shortness of breath occurred in clinical trials; these were mild or moderate and happened within 1 hour to 3 weeks of an infusion. Since approval, anaphylaxis and low blood pressure leading to fainting have been reported during or within an hour of an infusion. You will be monitored during your infusion and for 1 hour afterward. Get emergency medical help if you have hives, difficulty breathing, fainting, or swelling of your face, lips, tongue, or throat.
• Infusion-related reactions. These have been reported since approval and occurred during or within an hour of an infusion. The most common symptoms were high blood pressure, chills, shivering, and chest, abdominal, and back pain. If a severe reaction occurs, your infusion will be stopped.

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 Argenx at 1-833-argx411 or to the FDA at 1-800-FDA-1088.

Usual adult dose of Vyvgart for gMG

• 10 mg/kg as an IV infusion over 1 hour, once a week for 4 weeks.
• For patients weighing 120 kg or more: 1,200 mg (3 vials) per infusion.

Subsequent treatment cycles are given based on clinical evaluation. In clinical trials, patients received an average of 2 cycles over 26 weeks, and the safety of starting a new cycle 7 to 28 days after the last infusion was similar to that seen with longer gaps.

Call your healthcare provider to reschedule. A missed infusion may be given up to 3 days after the scheduled time. After that, the original dosing schedule is resumed until the treatment cycle is complete.

Live vaccines are not recommended during treatment with Vyvgart because it lowers IgG antibody levels. Talk to your healthcare provider about which vaccines you need before starting a new treatment cycle.

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.

Vyvgart may lower the levels and reduce the effectiveness of other medicines that bind to the neonatal Fc receptor (FcRn), such as immunoglobulin products, monoclonal antibodies, and antibody derivatives containing the human Fc domain of the IgG subclass. Your doctor will monitor you closely if you use these medicines. If you need one of these medicines long term, your doctor may stop Vyvgart and use a different treatment.

Vyvgart is not broken down by liver cytochrome P450 enzymes, so interactions with medicines affected by these enzymes are unlikely.

Vyvgart vials are stored in the refrigerator at 2°C to 8°C (36°F to 46°F) in the original carton to protect from light. Do not freeze or shake. Vyvgart is prepared and given by your healthcare provider.

Active ingredient: efgartigimod alfa-fcab 20 mg/mL

Inactive ingredients: arginine hydrochloride, histidine, L-histidine hydrochloride monohydrate, methionine, polysorbate 80, sodium chloride, sucrose, and water for injection.

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