A PHASE III, RANDOMIZED, DOUBLE-BLIND, PLACEBO-CONTROLLED, MULTICENTER STUDY TO EVALUATE EFFICACY, SAFETY, PHARMACOKINETICS, AND PHARMACODYNAMICS OF SATRALIZUMAB IN PATIENTS WITH GENERALIZED MYASTHENIA GRAVIS

• Age >= 12 years at time of signing Informed Consent Form
• Confirmed diagnosis of gMG
• MGFA class II, III or IV at screening
• A total MG-ADL score of >= 5 points at screening with more than 50% of this
score attributed to non-ocular items
• Ongoing gMG treatment at a stable dose and not exceeding the maximum protocol
allowed doses
• For female patients of childbearing potential: agreement to remain abstinent
(refrain from heterosexual intercourse) or use adequate contraception during
the treatment period and for at least 3 months after the final dose of
satralizumab

Exclusion Criteria Related to Myasthenia Gravis (MG):
• History of thymic cysts, thymoma, thymic carcinoma or other neoplasm of the
thymus as defined by the 2015 WHO classification of tumors of the thymus unless
deemed cured by adequate treatment with no evidence of recurrence for >= 5 years
before screening
• History of thymectomy within 6 months prior to screening
• Ocular MG (Myasthenia Gravis Foundation of America [MGFA] Class I)
• Myasthenic crisis within the last 3 months prior to screening (MGFA Class V)
• Known disease other than gMG that would interfere with the course and conduct
of the study

Exclusion Criteria Related to Previous or Concomitant Therapy:
• Use of IVIg or subcutaneous immunoglobulin (SCIg) within 6 weeks prior to
randomization (Day 1)
• Use of PE within 8 weeks prior to randomization (Day 1)
• Treatment with IL-6 inhibitory therapy (e.g., tocilizumab) at any time,
• Treatment with total body irradiation, or bone marrow transplantation at any
time
• Treatment with B and/or T cell-depleting agents
• Treatment with anti-CD20 ,within 6 months prior to screening, unless CD19
counts are within normal range, as assessed by the central laboratory at
screening
• For patients with prior exposure to anti-CD20 agents, CD19 counts below the
normal range, as assessed by the central laboratory at screening, or <6 months
since last anti-CD20 treatment till screening
• Treatment with C5 complement inhibitors (e.g., eculizumab orravulizumab)
within 6 months prior to screening
• Treatment with neonatal Fc receptor antagonist, within 6 months prior to
screening
• Treatment with or anti-B-lymphocyte stimulator monoclonal antibody at any time
• Treatment with cyclophosphamide IV within 6 months prior to screening
• Treatment with oral cyclophosphamide at any time
• Treatment with methotrexate within 8 weeks prior to screening
• Treatment with any investigational agent within 24 weeks prior to screening
or 5 drug-elimination half-lives of the investigational drug (whichever is
longer)
• Use of more than one IST as background therapy except for the combination of
an oral corticosteroids (OCS) with another permitted IST drug

General Safety Exclusion Criteria:
• Any surgical procedure (except for minor non-ophthalmic surgeries) within 4
weeks prior to screening
• Planned surgical procedure (except minor non-ophthalmic surgeries) during the
study
• Evidence of progressive multifocal leukoencephalopathy
• Evidence of serious uncontrolled concomitant diseases that may preclude
patient participation
• Congenital or acquired immunodeficiency, including human immunodeficiency
virus (HIV) infection
• Active or presence of recurrent bacterial, viral, fungal, mycobacterial
infection, or other infection, excluding fungal infection of nail beds or
dental caries
• Infection requiring hospitalization or treatment with IV anti-infective
agents within 4 weeks prior to baseline visit or oral anti-infective agents
within 2 weeks prior to baseline visit
• Positive screening tests for hepatitis B and C
• History of drug or alcohol abuse within 1 year prior to baseline
• History of diverticulitis or concurrent severe gastrointestinal (GI)
disorders that, in the investigator*s opinion, may lead to increased risk of
complications such as GI perforation
• Evidence of latent or active tuberculosis
• Receipt of live or live attenuated vaccine within 6 weeks prior to baseline
• History of blood donation (one unit or more), plasma donation or platelet
donation within 90 days prior to screening and Day 1
• History of malignancy within the last 5 years, including solid tumors,
hematologic malignancies and in situ carcinoma
• History of severe allergic reaction to a biologic agent
• Active suicidal ideation within 6 months prior to screening or history of
suicide attempt within 3 years prior to screening
• Any serious medical condition or abnormality in clinical laboratory tests
that, in the investigator's judgment, precludes the patient's safe
participation in and completion of the study
• Pregnant or breastfeeding, or intending to become pregnant during the study
or within 3 months after the final dose of satralizumab

Laboratory Exclusion Criteria (at Screening):
• White blood cells (WBC) < 3.0*10^3/microliter
• Absolute neutrophil count (ANC) < 2.0*10^3/microliter
• Absolute lymphocyte count < 0.5*10^3/microliter
• Platelet count < 10*10^4/microliter
• Aspartate aminotransferase (AST) or alanine transaminase (ALT) >1.5*upper
limit of normal (ULN)