The purpose of this 4-period study is to confirm the efficacy and safety of batoclimab in participants with gMG. In Period 1, participants will be randomized 1:1:1 to receive batoclimab 680 milligrams (mg) subcutaneously (SC) once a week (QW) or 340 mg SC QW or placebo. The primary efficacy endpoint will be assessed by change in the myasthenia gravis activities of daily living (MG- ADL) score in acetylcholine receptor antibody seropositive (AChRAb+) participants. In Period 2, participants previously treated with batoclimab will be re-randomized to stay on batoclimab (340 mg SC QW or 340 mg SC every two weeks) or receive placebo treatment. The secondary endpoint of maintenance of efficacy will be assessed by change in the MG- ADL score in AChRAb+ participants. Participants demonstrating a response to batoclimab during either Period 1 or 2 may enter the long-term extension (Period 3). Participants who complete Period 3 are eligible to participate in Period 4 (Optional Long-Term extension) according to their treatment assignment in Period 3.

Inclusion Criteria:

1. Are ≥ 18 years of age at the Screening Visit.
2. Have mild to severe gMG by Myasthenia Gravis Foundation of America (MGFA) classification Class II, III, or IVa at the Screening Visit.
3. Have a QMG score ≥ 11 at the Screening and Baseline Visits.
4. Have a MG-ADL score of ≥ 5 at the Screening and Baseline Visits.
5. Additional inclusion criteria are defined in the protocol.

Exclusion Criteria:

1. Have experienced myasthenic crisis within 3 months of the Screening Visit.
2. Have had a thymectomy performed < 6 months prior to the Screening Visit or have a planned thymectomy during the study period.
3. Have any active or untreated malignant thymoma.
4. Have received any agent or therapy (exclusive of those identified within inclusion criteria) with immunosuppressive properties (e.g., stem cell therapy, chemotherapies) within the past year.
5. Have used anti-FcRn treatment within 3 months prior to the Screening Visit or have a documented history of non-response to prior anti-FcRn treatment.
6. Additional exclusion criteria are defined in the protocol.

Sponsor Staff is also masked, so the study is Quadruple-blind.