To evaluate the safety and efficacy of tocilizumab in the treatment of generalized myasthenia gravis (gMG) as an extension study for the participants who previously completed Study tMG(NCT05067348).

tMG-E was an extension study designed to provide the participants who completed Study tMG an opportunity to receive tocilizumab and collect clinical data to provide long-term safety and efficacy information on tocilizumab in participants with gMG.

After receiving blinded study treatment (tocilizumab or placebo) in Study tMG for 16 weeks, participants were eligible to enroll in the tMG-E extension study. Participants were to enter Study tMG-E within 8 weeks after completing their Week 16 visit in Study tMG.

Study tMG-E consisted of an Open-Label treatment Phase up to 16 weeks.

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.