Evaluating the Long-Term Safety and Tolerability of Efgartigimod PH20 SC Administered Subcutaneously in Patients with Generalized Myasthenia Gravis

Inclusion Criteria:

1. Must be capable of giving signed informed consent, which includes compliance withthe requirements and restrictions listed in the informed consent form (ICF) and inthis protocol.

2. Previously participated in antecedent studies ARGX-113-2001 or ARGX-113-1705 and areeligible for roll over.

3. Contraceptive use by men and women should be consistent with local regulationsregarding the methods of contraception for those participating in clinical studiesand:

• Women of Child bearing potential (WOCBP) must have a negative urine pregnancytest at baseline before investigational medicinal product (IMP) can beadministered.

Exclusion Criteria:

1. The participant was discontinued early from studies ARGX-113-2001 or ARGX-113-1705,unless the reason for discontinuation from study ARGX-113-1705 was to roll over intostudy ARGX-113-2002. a. Participants who, in the investigator's judgment, are not benefiting fromefgartigimod IV in study ARGX-113-1705 Part B are not eligible for roll over intoARGX-113-2002.

2. Are pregnant or lactating, or intend to become pregnant during the study or within 90 days after the last dose of investigational medicinal product (IMP)

3. Has any of the following medical conditions:

4. Clinically significant uncontrolled chronic bacterial, viral, or fungalinfection at roll-over

5. Any other known autoimmune disease that, in the opinion of the investigator,would interfere with accurate assessment of clinical symptoms of myastheniagravis or put the participant at undue risk

6. History of malignancy unless deemed cured by adequate treatment with noevidence of reoccurrence for ≥3 years before the first administration ofinvestigational medicinal product (IMP).Participants with the following cancers can be included at any time:

• adequately treated basal cell or squamous cell skin cancer
• carcinoma in situ of the cervix
• carcinoma in situ of the breast
• incidental histological findings of prostate cancer (TNM classification ofmalignant tumors stage T1a or T1b)

4. Clinical evidence of other significant serious diseases, or the participant hashad a recent major surgery, or who have any other condition that, in theopinion of the investigator, could confound the results of the study or put theparticipant at undue risk

5. Received a live-attenuated vaccine within 28 days prior to study entry or plan toreceive a live-attenuated vaccine during the study

6. A known hypersensitivity reaction to efgartigimod, rHuPH20, or any of its excipients