• Age between 18 and 70 years old
• MG with generalized muscle weakness meeting criteria as defined by the MGFA class II, III, IVa, and IVb. Diagnosis should be supported by meeting at least 1 of the following 2 criteria: Positive serologic test for anti-AChR, anti-MuSK, or anti-LRP4 antibodies, based on historical record or test at Screening, or Evidence of response to acetylcholinesterase inhibitors AND history of abnormal neuromuscular transmission demonstrated by repetitive nerve stimulation or single-fiber electromyography. Seronegative cases must have negative genetic testing for congenital myasthenic syndrome, and, in those with only abnormal

jitter, mitochondrial disease excluded.

• If a patient is currently receiving standard therapy for MG, that treatment is required to be at a stable dose prior to Screening as follows, except for dose reduction due to safety or tolerability: Acetylcholinesterase inhibitors: Stable dose for ≥2 weeks, Corticosteroids: ≤30 mg prednisone or equivalent and on a stable dose for ≥2 weeks, Non-steroidal immunosuppressive drugs (e.g., azathioprine, methotrexate,

cyclosporine, tacrolimus, mycophenolate mofetil/mycophenolic acid, CY) initiated at least ≥12 weeks prior to Screening, with stable dose for ≥4 week.

Key

• MGFA class I or V
• Patients judged by the Investigator to be inappropriate for the study (e.g., at risk for requiring intubation during the study)
• Active or untreated thymoma, history of thymic carcinoma or thymic malignancy
• History of thymectomy within 52 weeks of Screening
• Clinical evidence of other serious concomitant medical disease, worsening muscle weakness secondary to concurrent infections or medications, or recent or planned major surgery, which could confound the results of the trial or place the participant at undue risk
• History of anaphylactic or severe systemic reaction to FLU, CY, or any of their metabolites