Terms and definitions


Here’s a list of commonly used terms related to gMG that may help you and your loved ones better understand gMG.

Sign up to get the latest information about VYVGART

  • Acetylcholine (ACh)
    Acetylcholine helps carry messages from the brain to different parts of the body, including muscles. In gMG, harmful AChR antibodies damage the receptors for acetylcholine on muscles, which causes muscle weakness.
  • Acetylcholine receptor (AChR)
    A type of receptor (message receiver) found on muscles. These receptors receive messages from nerves that tell muscles what to do. Patients with gMG who have antibodies that damage AChR receptors are called anti-AChR antibody positive gMG patients. Anti-AChR antibody positive is the most common type of gMG.
  • Acetylcholine receptor (AChR) antibody
    Sometimes the immune system mistakenly makes IgG antibodies that target AChR receptors. These are known as harmful AChR antibodies. gMG patients with harmful AChR antibodies have anti-AChR antibody positive gMG.
    IgG=immunoglobulin G.
  • Anti-AChR antibody positive gMG
    The most common type of gMG. People with gMG who have harmful antibodies that damage AChR are called anti-AChR antibody positive gMG patients.
  • Antibody fragment
    An antibody fragment is only part of a whole antibody. For example, the bottom section of the Y-shaped antibody is a fragment.
  • Autoimmune
    Autoimmune means that the immune system, which normally protects you, is mistakenly attacking itself.
  • Biologics
    Biologics are medications created from living things. They target specific parts of the immune system to treat various types of gMG. VYVGART Hytrulo is a biologic medication approved by the FDA as an add-on treatment for adults with anti-AChR antibody positive gMG.
  • First-line treatment
    Medications that are commonly used as a first gMG treatment option. First-line treatments can include steroids, anticholinesterase inhibitors, and immunosuppressive therapies.
  • Immunoglobulin G (IgG) antibody
    A Y-shaped protein made by the immune system. Antibodies attach to different things to let the immune system know that there is a potential threat that it will need to destroy or neutralize. Antibodies can attach to disease-causing substances like bacteria and viruses.
  • Immunosuppressive therapy (IST)
    A type of medication used to reduce the strength of the body’s immune system. It is often used to treat conditions where the immune system is overactive, like in autoimmune diseases.
  • Intravenous (IV) infusion
    Given by inserting a needle into a vein so that the medication enters the bloodstream. 
  • Myasthenia Gravis Activities of Daily Living (MG-ADL) scale
    The MG-ADL scale assesses the impact of gMG on daily functions by measuring 8 signs or symptoms that are commonly affected in gMG: the ability to speak, chew, swallow, breathe, brush teeth or comb hair, and get out of a chair, as well as the frequency of double vision and eyelid droop. Each item is measured on a 4-point scale, where a score of 0 represents normal function and a score of 3 represents the loss of ability to perform that function. Total scores range from 0 to 24 points, with a higher score showing more severe gMG.
  • Neonatal Fc receptor (FcRn)
    In gMG, FcRn receptors play an important role. They extend the life of IgG antibodies. This includes harmful AChR antibodies, which are the main cause of gMG symptoms. FcRn receptors can be occupied by gMG treatments like VYVGART Hytrulo. When this happens, more harmful AChR antibodies are destroyed and removed.
  • Placebo
    An inactive substance used in a study that looks like the medicine being tested.
  • Prefilled syringe
    A one-time use (single-dose) syringe that’s already filled with a dose of medication. VYVGART Hytrulo can be given as a subcutaneous injection into the layer beneath the skin using a prefilled syringe.
  • Quantitative Myasthenia Gravis (QMG) scale
    The QMG scale assesses muscle weakness in gMG based on 13 items. Each item is assessed on a 4-point scale, where a score of 0 represents no muscle weakness and a score of 3 represents severe muscle weakness. Total scores range from 0 to 39, with a higher score meaning muscle weakness is more severe.
  • Specialty pharmacy
    A specialty pharmacy provides medications that require special handling, storage, and delivery.
  • Study
    A study, also known as a clinical trial, is a type of research that tests the safety and effectiveness of a treatment in people. The FDA reviews the results of studies to determine if a treatment is safe and effective for use in a specific condition.
  • Subcutaneous injection
    Given by delivering medicine into the layer under the skin.
VYVGART Hytrulo (efgartigimod alfa and hyaluronidase-qvfc) | VYVGART (efgartigimod alfa-fcab)
VYVGART Hytrulo (efgartigimod alfa and hyaluronidase-qvfc) | VYVGART (efgartigimod alfa-fcab)

Still have questions? Call 1-833-VYVGART (1-833-898-4278) to speak with an educator about gMG, how VYVGART works in the body, study data, cost and coverage, and more.

Do not take VYVGART if you are allergic to efgartigimod alfa or any of the ingredients in VYVGART. Do not take VYVGART HYTRULO if you are allergic to efgartigimod alfa, hyaluronidase, or any of the ingredients in VYVGART HYTRULO. VYVGART or VYVGART HYTRULO can cause serious allergic reactions and a decrease in blood pressure leading to fainting.

Before taking VYVGART or VYVGART HYTRULO, tell your healthcare provider about all of your medical conditions, including if you:

  • have an infection or fever.
  • have recently received or are scheduled to receive any vaccinations.
  • have any history of allergic reactions.
  • have kidney (renal) problems.
  • are pregnant or plan to become pregnant. It is not known whether VYVGART or VYVGART HYTRULO will harm your unborn baby.
    • Pregnancy Exposure Registry. There is a pregnancy exposure registry for women who use VYVGART or VYVGART HYTRULO 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 VYVGARTPregnancy.com
  • are breastfeeding or plan to breastfeed. It is not known if VYVGART or VYVGART HYTRULO passes into your breast milk.

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

VYVGART or VYVGART HYTRULO can cause side effects which can be serious, including:

  • Infection. VYVGART or VYVGART HYTRULO may increase the risk of infection. If you have an active infection, your healthcare provider should delay your treatment with VYVGART or VYVGART HYTRULO until your infection is gone. Tell your healthcare provider right away if you get any of the following signs and symptoms of an infection:
    • fever
    • chills
    • frequent and painful urination
    • cough
    • pain and blockage of nasal passages
    • wheezing
    • shortness of breath
    • sore throat
    • excess phlegm
    • nasal discharge
  • Allergic reactions (hypersensitivity reactions). VYVGART or VYVGART HYTRULO can cause allergic reactions that can be severe. These reactions can happen during, shortly after, or weeks after your VYVGART infusion or VYVGART HYTRULO injection. Tell your healthcare provider or get emergency help right away if you have any of the following symptoms of an allergic reaction with VYVGART or VYVGART HYTRULO:
    • rash
    • swelling of the face, lips, throat, or tongue
    • shortness of breath
    • trouble breathing
    • low blood pressure
    • fainting

An additional symptom of an allergic reaction with VYVGART HYTRULO can include hives.

  • Infusion or injection-related reactions. VYVGART can cause infusion-related reactions. VYVGART HYTRULO can cause infusion or injection-related reactions. These reactions can happen during or shortly after your VYVGART infusion or VYVGART HYTRULO injection. Tell your healthcare provider if you have any of the following symptoms of an infusion or injection-related reaction:
    • high blood pressure
    • chills
    • shivering
    • chest, stomach, or back pain

The most common side effects of VYVGART or VYVGART HYTRULO include respiratory tract infection, headache, and urinary tract infection. An additional common side effect with VYVGART HYTRULO includes injection site reactions.

These are not all the possible side effects of VYVGART or VYVGART HYTRULO. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What is VYVGART® (efgartigimod alfa-fcab) for intravenous (IV) infusion and what is VYVGART HYTRULO® (efgartigimod alfa and hyaluronidase-qvfc) for subcutaneous injection?

VYVGART and VYVGART HYTRULO are both prescription medicines used to treat adults with generalized myasthenia gravis (gMG) who are anti-acetylcholine receptor (AChR) antibody positive.

It is not known if VYVGART or VYVGART HYTRULO is safe and effective in children.

Please see full Prescribing and Patient Information for VYVGART HYTRULO for subcutaneous injection and full Prescribing Information for VYVGART for IV infusion.

Dosage forms and strengths:

VYVGART Hytrulo is available as a single-dose subcutaneous injection containing: 200 mg/mL of efgartigimod alfa and 2,000 U/mL of hyaluronidase per prefilled syringe, or 180 mg/mL of efgartigimod alfa and 2,000 U/mL of hyaluronidase per vial. VYVGART is available as a single-dose injection for intravenous use containing 400 mg/20 mL of efgartigimod alfa-fcab per vial.

Do not take VYVGART if you are allergic to efgartigimod alfa or any of the ingredients in VYVGART. Do not take VYVGART HYTRULO if you are allergic to efgartigimod alfa, hyaluronidase, or any of the ingredients in VYVGART HYTRULO. VYVGART or VYVGART HYTRULO can cause serious allergic reactions and a decrease in blood pressure leading to fainting.

Before taking VYVGART or VYVGART HYTRULO, tell your healthcare provider about all of your medical conditions, including if you:

  • have an infection or fever.
  • have recently received or are scheduled to receive any vaccinations.
  • have any history of allergic reactions.
  • have kidney (renal) problems.
  • are pregnant or plan to become pregnant. It is not known whether VYVGART or VYVGART HYTRULO will harm your unborn baby.
    • Pregnancy Exposure Registry. There is a pregnancy exposure registry for women who use VYVGART or VYVGART HYTRULO 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 VYVGARTPregnancy.com
  • are breastfeeding or plan to breastfeed. It is not known if VYVGART or VYVGART HYTRULO passes into your breast milk.

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

VYVGART or VYVGART HYTRULO can cause side effects which can be serious, including:

  • Infection. VYVGART or VYVGART HYTRULO may increase the risk of infection. If you have an active infection, your healthcare provider should delay your treatment with VYVGART or VYVGART HYTRULO until your infection is gone. Tell your healthcare provider right away if you get any of the following signs and symptoms of an infection:
    • fever
    • chills
    • frequent and painful urination
    • cough
    • pain and blockage of nasal passages
    • wheezing
    • shortness of breath
    • sore throat
    • excess phlegm
    • nasal discharge
  • Allergic reactions (hypersensitivity reactions). VYVGART or VYVGART HYTRULO can cause allergic reactions that can be severe. These reactions can happen during, shortly after, or weeks after your VYVGART infusion or VYVGART HYTRULO injection. Tell your healthcare provider or get emergency help right away if you have any of the following symptoms of an allergic reaction with VYVGART or VYVGART HYTRULO:
    • rash
    • swelling of the face, lips, throat, or tongue
    • shortness of breath
    • trouble breathing
    • low blood pressure
    • fainting

An additional symptom of an allergic reaction with VYVGART HYTRULO can include hives.

  • Infusion or injection-related reactions. VYVGART can cause infusion-related reactions. VYVGART HYTRULO can cause infusion or injection-related reactions. These reactions can happen during or shortly after your VYVGART infusion or VYVGART HYTRULO injection. Tell your healthcare provider if you have any of the following symptoms of an infusion or injection-related reaction:
    • high blood pressure
    • chills
    • shivering
    • chest, stomach, or back pain

The most common side effects of VYVGART or VYVGART HYTRULO include respiratory tract infection, headache, and urinary tract infection. An additional common side effect with VYVGART HYTRULO includes injection site reactions.

These are not all the possible side effects of VYVGART or VYVGART HYTRULO. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What is VYVGART® (efgartigimod alfa-fcab) for intravenous (IV) infusion and what is VYVGART HYTRULO® (efgartigimod alfa and hyaluronidase-qvfc) for subcutaneous injection?

VYVGART and VYVGART HYTRULO are both prescription medicines used to treat adults with generalized myasthenia gravis (gMG) who are anti-acetylcholine receptor (AChR) antibody positive.

It is not known if VYVGART or VYVGART HYTRULO is safe and effective in children.

Please see full Prescribing and Patient Information for VYVGART HYTRULO for subcutaneous injection and full Prescribing Information for VYVGART for IV infusion.

Dosage forms and strengths:

VYVGART Hytrulo is available as a single-dose subcutaneous injection containing: 200 mg/mL of efgartigimod alfa and 2,000 U/mL of hyaluronidase per prefilled syringe, or 180 mg/mL of efgartigimod alfa and 2,000 U/mL of hyaluronidase per vial. VYVGART is available as a single-dose injection for intravenous use containing 400 mg/20 mL of efgartigimod alfa-fcab per vial.