A Study of Nipocalimab in Children Aged 2 to Less Than 18 Years With Generalized Myasthenia Gravis

Key Inclusion Criteria:

• Age: For US sites only: 8 to < 18 years

• Diagnosis of myasthenia gravis (MG) with generalized muscle weakness meeting theclinical criteria for generalized myasthenia gravis (gMG) as defined by theMyasthenia Gravis Foundation of America (MGFA) Clinical Classification Class IIa/b,IIIa/b, or IVa/b at screening

• Has a positive serologic test for acetylcholine receptor (anti-AChR) antibodies ormuscle-specific tyrosine kinase (anti-MuSK) antibodies at screening

• A participant using herbal, naturopathic, traditional Chinese remedies, ayurvedic ornutritional supplements, or medical marijuana (with a doctor's prescription) iseligible if the use of these medications is acceptable to the Investigator. Theseremedies must remain at a stable dose and regimen throughout the study

• Has sufficient venous access to allow drug administration by infusion and bloodsampling as per the protocol

• Participants should have a body weight and body mass index between 5th and 95thpercentile for age and sex. Obese participants greater than 95th percentile andunderweight participants below 5th percentile may participate following medicalclearance

• A female of childbearing potential must have a negative highly sensitive serum (beta-human chorionic gonadotropin [beta-hCG]) at Screening and a negative urinepregnancy test at Day 1 prior to administration of study intervention

Key Exclusion Criteria:

• Has a history of severe and/or uncontrolled hepatic (example, viral/alcoholic/autoimmune hepatitis/ cirrhosis/ and/or metabolic liver disease), gastrointestinal,renal, pulmonary, cardiovascular (including congenital heart diseases), psychiatric,neurological musculoskeletal disorder, any other medical disorder(s) (example,diabetes mellitus), risk factors for thrombosis events (example, a history of venousthromboembolism [VTE] or antiphospholipid syndrome, or a personal or family historyof heritable coagulation disorder such as factor V leiden, protein S or protein Cdeficiency, atrial fibrillation/flutter, major orthopedic surgery or significanttrauma that may increase the risk of VTE, is expected to be immobilized forprolonged periods of time), or has clinically significant abnormalities in screeninglaboratory, that might interfere with participant's full participation in the study,and/ or might jeopardize the safety of the participant or the validity of the studyresults

• Has any confirmed or suspected clinical immunodeficiency syndrome not related totreatment of his/her generalized myasthenia gravis (gMG), or has a family history ofcongenital or hereditary immunodeficiency unless confirmed absent in the participant

• Has had a thymectomy within 12 months prior to screening, or thymectomy is plannedduring the Active treatment Phase of the study

• Has shown a previous severe immediate hypersensitivity reaction, such as anaphylaxisto therapeutic proteins (example, monoclonal antibodies)

• Has experienced myocardial infarction, unstable ischemic heart disease, or strokewithin 12 weeks of screening