An Efficacy and Safety Study of ARGX-113 in Patients With Myasthenia Gravis Who Have Generalized Muscle Weakness

Inclusion Criteria: 1. Patients with the ability to understand the requirements of the trial, provide written informed consent, and comply with the trial protocol procedures. 2. Male or female patients aged ≥ 18 years. 3. Diagnosis of MG with generalized muscle weakness meeting the clinical criteria for diagnosis of MG as defined by the Myasthenia Gravis Foundation of America (MGFA) class II, III, IVa and IVb. Other, more specific inclusion criteria are defined in the protocol Exclusion Criteria: 1. Pregnant and lactating women, and those intending to become pregnant during the trial or within 90 days after the last dosing. 2. Male patients who are sexually active and do not intend to use effective methods of contraception during the trial or within 90 days after the last dosing or male patients who plan to donate sperm during the trial or within 90 days after the last dosing. 3. MGFA Class I and V patients. 4. Patients with worsening muscle weakness secondary to concurrent infections or medications. 5. Patients with known seropositivity or who test positive for an active viral infection at Screening with: * Hepatitis B Virus (HBV) (except patients who are seropositive because of HBV vaccination) * Hepatitis C Virus (HCV) * Human Immunodeficiency Virus (HIV) Other, more specific exclusion criteria are further defined in the protocol.