Efgartigimod in IVIG Dependent Myasthenia Gravis Patients

Inclusion Criteria: * 1\. Signed informed consent. 2. Age 18-80 years 3. Acetylcholine receptor antibody positive, myasthenia gravis patients, with stable disease for the past four or more months. Stable disease is defined as no change in dosage or interval in IVIG treatments and without any significant change in clinical status. 4\. No modification or addition of NSISTs in the past six months 5. No modification or addition in corticosteroid therapy for the past three months 6. Myasthenia Gravis diagnosis was supported by abnormal neurotransmission test or history of improvement with AChE inhibitors. 7\. Receiving chronic regular IVIG treatments for myasthenia gravis for the past year or more. Exclusion Criteria: * 1\. Patients with previous rituxan or eculizumab treatment or plasma exchange within the past six months 2. Patients with previous thymectomy within the past 3months 3. Patients that have active Hepatitis B, are seropositive for Hepatitis C or HIV or have latent, untreated or active TB or any other significant active infection 4. Patients that have at screening a serum IgG less than 6.0gm/L or a history of chronic hypogammaglobulinemia from any cause. 5\. Patients that are pregnant or considering becoming pregnant in the next 6 months. 6\. Patients with severe renal impairment (eGFR less than 30ml/min) 7. Patients who in the opinion of the investigator should not participate in the study.