PK, PD, Safety, and Efficacy Study of Gefurulimab in Pediatric Patients With AChR+ Generalized Myasthenia Gravis

Inclusion Criteria:

United States of America (USA) specific inclusion criterion:

• Participant must be 12 to < 18 years of age at the time of signing the informedconsent/assent.

• All participants must be vaccinated against meningococcal infection from serogroupsA, B, C, W, and Y within 3 years and at least 2 weeks prior to the first dose ofstudy intervention administration.

Rest of World (ROW) specific inclusion criteria:

• Participant must be 6 to < 18 years of age at the time of signing the informedconsent/assent.

• All participants must be vaccinated against meningococcal infection from serogroupsA, C, W, Y (and B where available) within 3 years prior to study intervention on Day

1. If vaccination occurs < 2 weeks prior to Day 1, the participants will receiveprophylactic antibiotics for at least 2 weeks after initial meningococcalvaccination for serogroups A,C,W,Y (and B, where available)

Global inclusion criteria:

• Diagnosis of MG with generalized muscle weakness meeting the clinical criteriadefined by Myasthenia Gravis Foundation of America (MGFA) Class II, III or IV

• Positive serological test for autoantibodies against AChR

Exclusion Criteria:

• History of thymectomy, or any other thymic surgery within 12 months prior toScreening

• Untreated thymic malignancy, carcinoma, or thymoma

• History of Neisseria meningitidis infection

• Pregnancy, breastfeeding, or intention to conceive during the course of the study