Open-Label Extension of Tocilizumab in Subjects With Generalized Myasthenia Gravis

Inclusion Criteria: 1. Participant has completed Study tMG. 2. Participant has given written informed consent. 3. MG-ADL score ≥ 5 points, or a decrease of ≤ 3 points relative to the baseline MG-ADL of the tMG study Exclusion Criteria: 1. Participants had clinically relevant active infections (such as sepsis, pneumonia, or abscess) or severe infections (resulting in hospitalization or requiring antibiotic treatment) in the past 4 weeks; 2. Those with high-risk tuberculosis infection, acquired tuberculosis infection, and chronic hepatitis after the tMG study; 3. planned thymectomy during RCP; 4. Received IVIG or plasma exchange in the past 4 weeks; 5. Any medical condition or circumstances that, in the opinion of the investigator, might have interfered with the participant's participation in the study, posed any added risk for the participant, or confounded the assessment of the participants.