Efgartigimod alfa is used in adults to treat myasthenia gravis.

Efgartigimod alfa may also be used for purposes not listed in this medication guide.

Call your doctor at once if you have fever, chills, sore throat, body aches, unusual tiredness, loss of appetite, bruising or bleeding; or hives, difficult breathing, swelling of your face, lips, tongue, or throat.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Efgartigimod alfa is injected into a vein by a healthcare provider. efgartigimod alfa is given over 1 hour once a week for 4 weeks.

Doses are based on weight. Your dose may change if you gain or lose weight.

You will be watched for a short time to make sure you do not have an allergic reaction.

Make sure you are current on all vaccines before you start using efgartigimod alfa.

Usual Adult Dose for Myasthenia Gravis:

10 mg/kg IV once weekly for 4 weeks
-Weight greater than 120 kg: 1200 mg IV once weekly for 4 weeks

Comments:
-Subsequent treatment cycles should be based on clinical evaluation.
-The safety of initiating a cycle sooner than 50 days from the start of the prior cycle has not been established.
-Evaluate the need for age-appropriate immunizations prior to therapy initiation.

Use: For the treatment of generalized myasthenia gravis in patients who are anti-acetylcholine receptor antibody positive.

Tell your doctor if you currently have an infection or had any infections recently.

Tell your doctor if you are pregnant or plan to become pregnant, or breastfeeding or plan to breastfeed.

Call your doctor for instructions if you miss an appointment for your efgartigimod alfa injection.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Avoid receiving a "live" vaccine while you are being treated with efgartigimod alfa.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Efgartigimod alfa may cause serious side effects. Call your doctor at once if you have:

• signs of infection--fever, chills, sore throat, body aches, unusual tiredness, loss of appetite, bruising or bleeding.

Common side effects of efgartigimod alfa may include:

• cold symptoms such as stuffy nose, sneezing, sore throat;

• headache; or

• pain and burning when you urinate, painful urination.

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 FDA at 1-800-FDA-1088.

Other drugs may affect efgartigimod alfa, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all other medicines you use.