A Study of Efgartigimod PH20 SC in Children Between 2 and Less Than 18 Years of Age With Generalized Myasthenia Gravis

Inclusion Criteria: * The participant (and/or their legally authorized representative) understands the requirements of the study and is capable of providing written informed consent/assent and complying with protocol requirements * The participant is aged 2 to \<18 years at the time of informed consent/assent * The participant has been diagnosed with generalised Myasthenia Gravis that is supported by a physical examination and confirmed seropositivity for anti-acetylcholine receptor antibodies * The participant has had an unsatisfactory response to immunosuppressants, corticosteroids, or acetylcholinesterase inhibitors but is on stable concomitant MG therapy. If receiving corticosteroids and/or immunosuppressants, must be on a stable dose for ≥1 month before screening * The participant agrees to use birth control consistent with local regulations and people of child-bearing potential must have a negative blood pregnancy test at screening and a negative urine pregnancy test before receiving the study drug Exclusion Criteria: * Is a female adolescent of child-bearing potential who is pregnant and/or lactating or intends to become pregnant during their participation in the study * Has worsening muscle weakness secondary to a concurrent infection or as a result of a medication * Has a documented lack of clinical response to plasma exchange (PLEX) * Received a live or live-attenuated vaccine within \<4 weeks before screening * Received a thymectomy within 3 months before screen…