The primary study objective is to evaluate medium- and long-term safety of HBM9161 in combination with background treatment for gMG patients through the observation on adverse events and laboratory abnormalities during study period.

Inclusion Criteria:

1. Completed the HBM9161.3 Phase 3 study
2. Signed written informed consent.
3. Suitable for continued treatment with HBM9161 as judged by the investigator.
4. Female patients of childbearing potential and male patients with female partners of childbearing potential can participate in this study, but reliable contraceptive measures must be taken (such as physical barrier contraception (patients and their partners), contraceptive pills or patches, spermicide and barrier or intrauterine device). Up to 60 days after the last dose.
5. A negative urine pregnancy at baseline must be observed for women of childbearing age.

Exclusion Criteria:

1. Had received any other clinical study drug since the administration of the study drug in the 9161.3 Phase 3 study.
2. Females who are pregnant or lactating or planning to become pregnant during the study period, or females of childbearing potential who are not using an effective method of contraception.