Efgartigimod alfa

Pronunciation: ef-gar-TIJ-i-mod.

Generic name
efgartigimod alfa
Drug class
FcRn (neonatal Fc receptor) blocker -- antibody fragment
Form
IV infusion (400 mg/20 mL vial)
Route
Intravenous infusion
Legal status
Prescription-only, specialist-initiated (neurology), given by IV infusion at a treatment centre

Availability and supply rules vary by country

Trade names by country: United States · United Kingdom · Canada · Australia

Australia: Vyvgart (4) · Full directory

What efgartigimod alfa is and how it works

Efgartigimod alfa is a prescription-only medicine given by infusion for generalized myasthenia gravis, an autoimmune condition that causes muscle weakness. It works by reducing certain harmful antibodies in the blood. (1)

Efgartigimod alfa is given as a series of weekly infusions for 4 weeks, then your neurologist assesses you before deciding on further treatment cycles, which are spaced at least 4 weeks apart. It is given at a specialist infusion centre, not something you take at home.

Mechanism of action: how efgartigimod alfa works

Efgartigimod alfa is an antibody Fc-fragment that binds the neonatal Fc receptor (FcRn), blocking IgG recycling and reducing circulating pathogenic IgG autoantibodies, including the anti-acetylcholine-receptor antibodies that drive myasthenia gravis. (1)

What efgartigimod alfa is used for

Generalized myasthenia gravis (gMG)

Used to treat generalized myasthenia gravis in adults, an autoimmune condition causing muscle weakness, particularly in people who test positive for anti-acetylcholine receptor (AChR) antibodies. (1)

Before taking efgartigimod alfa

Do not take / not appropriate for

  • Do not use efgartigimod alfa if you have had a serious allergic reaction to it or any of its ingredients. (all countries) (1)

Tell your clinician about

  • Any current infection, or a history of frequent infections.
  • Any previous allergic reaction, fainting, or low blood pressure during an infusion of this or a similar medicine.
  • All other medicines you take.
  • Pregnancy, plans for pregnancy, or breastfeeding.
(1)

How to take efgartigimod alfa

  • Efgartigimod alfa is given as an infusion into a vein over about an hour, once a week for 4 weeks -- this is one treatment cycle.
  • Your neurologist will assess your symptoms before deciding whether and when you need another treatment cycle, with at least 4 weeks between cycles.
  • You will be monitored during and for a period after each infusion for signs of an allergic reaction or a drop in blood pressure.
(1)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3) (4)

Missed dose

If a scheduled infusion is missed, it can usually still be given up to 3 days late, and your original weekly schedule then continues. Contact your treatment centre if you miss an appointment.

Overdose

Efgartigimod alfa is given under direct medical supervision, so any dosing concerns are managed by the treating team at the time. (1)

Side effects

Side effects and their urgency vary; report severe, persistent, or concerning symptoms.

Respiratory tract infections (such as colds) are common.

What to notice: Respiratory tract infections (such as colds) are common.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Headache.

What to notice: Headache.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Urinary tract infections.

What to notice: Urinary tract infections.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Serious warnings

Signs of a reaction during or shortly after the infusion — emergency

Symptoms: Swelling of the face, lips, tongue, or throat; difficulty breathing; dizziness or fainting; a fast or irregular heartbeat; chest, stomach, or back pain; chills or shivering.

Action: Tell the infusion team immediately -- these reactions have occurred during or within an hour of the infusion and can lead to treatment being stopped for that session. (1)

Signs of infection — high caution

Symptoms: Fever, cough, pain when urinating, or feeling generally unwell.

Action: Tell your neurologist -- this medicine increases the risk of respiratory and urinary infections, so new symptoms should be reported promptly. (1)

Interactions

  • This medicine can lower the blood levels of other medicines that work in a similar way (binding the same protein, called the neonatal Fc receptor), which could make them less effective -- tell your prescriber about all other medicines you take, especially other antibody-based treatments. (1)

Pregnancy, breastfeeding, kidney/liver function, age

Pregnancy

There is no human data on use in pregnancy. Animal studies at much higher doses than used in humans did not show harm to the developing baby. This medicine reduces certain antibodies in the mother's blood, which may reduce the natural antibody protection normally passed to a baby before birth. A pregnancy registry tracks outcomes for those exposed during pregnancy. (1) (2) (3) (4)

Breastfeeding

Not established in the source reviewed for this dossier; discuss with your neurologist. (1) (2) (3) (4)

Children

Not established as safe/effective in children in the source reviewed. (1) (2) (3) (4)

Elderly

No specific dose adjustment based on age alone is described in the source reviewed. (1) (2) (3) (4)

Hepatic_impairment

Not established in the source reviewed for this dossier. (1) (2) (3) (4)

Renal_impairment

Not established in the source reviewed for this dossier. (1) (2) (3) (4)

Monitoring

Before starting

  • Antibody test result (AChR-antibody status)
  • Screening for active infection

During treatment

  • Close monitoring during and for a period after each infusion for allergic reaction or blood pressure changes.
  • Regular neurological assessment to decide on further treatment cycles.
  • Ongoing awareness of infection symptoms.
(1)

Storage

Efgartigimod alfa is stored and prepared by the treatment centre; patients do not typically store or handle it themselves.

Professional information

Clinician-facing context only, sourced from the current US FDA prescribing information; verify against the current full label before prescribing.

United States

Indication: Generalized myasthenia gravis

Dose summary: 10 mg/kg IV over 1 hour, once weekly x4 doses per cycle (1,200mg flat dose if >=120kg). Subsequent cycles per clinical evaluation, minimum 28-day interval between cycles (accelerated 7-28 day dosing has been studied). Missed infusion may be given up to 3 days late.

Renal context: Not established in the source reviewed for this dossier. (1)

Mechanism of action

Hepatic guidance

Not established in the source reviewed for this dossier.

Overdose note

Administered under direct medical supervision at every dose; no self-administered overdose scenario applies. (1)

Frequently asked questions

Is efgartigimod alfa (Vyvgart) available in the US, UK, Europe, Canada, and Australia?

Yes, it is approved in all of these regions for AChR-antibody-positive generalized myasthenia gravis. New Zealand-specific approval was not found in this research and should be confirmed locally. (1) (2) (3) (4)

Do I need to keep getting infusions forever?

Not necessarily on a fixed schedule -- after an initial 4-week cycle, your neurologist assesses your symptoms and decides whether and when you need another treatment cycle, based on how you're doing. (1)

What reactions can happen during or right after a Vyvgart infusion?

Reactions can occur during the infusion or within about an hour afterward, including a serious allergic reaction (anaphylaxis) or a sudden drop in blood pressure causing fainting, as well as milder reactions like high blood pressure, chills, shivering, or chest, stomach, or back pain. Your infusion is given in a monitored setting so these can be recognised and treated quickly. (1)

What is the mechanism of action of efgartigimod alfa?

Efgartigimod alfa is an antibody Fc-fragment that binds the neonatal Fc receptor (FcRn), blocking IgG recycling and reducing circulating pathogenic IgG autoantibodies, including the anti-acetylcholine-receptor antibodies that drive myasthenia gravis. (1)

What is the generic name of Efgartigimod alfa?

The generic name is efgartigimod alfa. (1)

What class of drug is efgartigimod alfa?

Efgartigimod alfa is classed as: FcRn (neonatal Fc receptor) blocker -- antibody fragment. (1)

References

  1. VYVGART (efgartigimod alfa-fcab) -- full prescribing informationU.S. Food and Drug Administration / DailyMed (NIH), full prescribing information, argenx US Inc. · United States · accessed 2026-07-29 · source 1
  2. European Commission and UK MHRA approval of VYVGART (efgartigimod alfa)argenx corporate press releases · European Union / United Kingdom · accessed 2026-07-29 · source 2
  3. Health Canada Notice of Compliance for VYVGARTargenx corporate press releases / Health Canada · Canada · accessed 2026-07-29 · source 3
  4. VYVGART (Argenx Australia Pty Ltd) -- TGA registrationTherapeutic Goods Administration (TGA), Australia · Australia · accessed 2026-07-29 · source 4

Brand names by country

Single-ingredient efgartigimod alfa names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

  • VYVGART20 mg/mL · argenx us

United Kingdom

  • Vyvgart (2)MHRA approved 2023-03 confirmed · not specified in fetched source · argenx UK Limited

Canada

  • Vyvgart (3)Health Canada Notice of Compliance 2023-09 · not specified in fetched source · argenx Canada

Australia

  • Vyvgart (4)TGA registered confirmed · not specified in fetched source · Argenx Australia Pty Ltd
View brands in additional countries.

European Union

Vyvgart (2)