Myasthenia Gravis Inebilizumab Trial (MINT)

This study is a phase 3, randomized, double-blind, placebo-controlled study, to be conducted at approximately 100 study sites. Approximately 270 subjects (188 AChR-Ab+ and 82 MuSK-Ab+) will be enrolled. Patients with MG who are positive for anti-AChR or anti-MuSK antibodies will be enrolled and analyzed separately as 2 populations: (1) AChR-Ab+ and (2) MuSK-Ab+. Patients who do not have anti-AChR or anti-MuSK antibodies will not be enrolled. Patients with MGFA classification II, III, or IV disease, MG-ADL score ≥ 6, QMG score ≥ 11, and use of a corticosteroid and/or non-steroidal immunosuppressant will be included in the study.

All subjects who complete the randomized controlled period will have the option to enroll in a 1.5-year open-label period.

Inclusion Criteria:

1. Diagnosis of MG with anti-AChR or anti-MuSK antibody.
2. MGFA Clinical Classification Class II, III, or IV.
3. MG-ADL score of 6 or greater at screening and at randomization with > 50% of this score attributed to non-ocular items.
4. QMG score of 11 or greater.
5. Subjects must be on:
   1. Corticosteroids only, with no dose increase within 4 weeks prior to randomization, or
   2. One allowed non-steroidal IST, with continuous use for at least 6 months prior to randomization and no dose increase within 4 months prior to randomization, or
   3. Combination of (1) corticosteroids with no dose increase within 4 weeks prior to randomization and (2) one allowed non-steroidal IST with continuous use for at least 6 months prior to randomization and no dose increase within 4 months prior to randomization.

Allowed ISTs, alone or in combination with corticosteroids, are azathioprine, mycophenolate mofetil, and mycophenolic acid.

Exclusion Criteria:

1. Receipt within the 4 weeks prior to Day 1:
   1. Cyclosporine (except eye drops)
   2. Tacrolimus (except topical)
   3. Methotrexate
2. Current use of:
   1. Prednisone > 40 mg/day or > 80 mg over a 2-day period (or equivalent dose of other corticosteroids)