Evaluation of PK, PD, Efficacy, Safety, and Immunogenicity of IV Ravulizumab in Pediatric Participants With Generalized Myasthenia Gravis

The primary purpose of this study is to characterize the pharmacokinetics and pharmacodynamics of treatment with ravulizumab intravenous infusion in pediatric participants with gMG.

Inclusion Criteria: * Diagnosis of gMG confirmed by a positive serologic test for anti-AChR antibodies (Abs) obtained at Screening and/or during Screening Period * Myasthenia Gravis Foundation of America (MGFA) Clinical Classification of Class II to Class IV at Screening * Participants receiving treatment must be on a stable dosing regimen of adequate duration prior to Screening and during the Screening Period. * Eculizumab-experienced participants must have been enrolled and treated with eculizumab in Study ECU-MG-303 for at least 6 months (180 days) and must have been on a stable dose for ≥ 2 months (60 days) prior to Screening. * All participants must be vaccinated against meningococcal infection Exclusion Criteria: Medical Conditions * Any untreated thymic malignancy, carcinoma, or thymoma. * Participants with a history of treated benign thymoma * History of thymectomy, thymomectomy, or any thymic surgery within the 12 months prior to Screening * History of N meningitidis infection * Known to be human immunodeficiency virus (HIV) positive * History of unexplained infections * Known or suspected history of drug or alcohol abuse or dependence within 1 year prior to the start of the Screening Period