The purpose of the current study is to assess the effectiveness and safety/tolerability of three dose regimens of RVT-1401 in the treatment of active, moderate to severe GO patients. In addition, the study is designed to measure the amount of RVT-1401 in the blood at different times, measure how antibodies in the blood are affected by RVT-1401, and to examine how RVT-1401 affects GO symptoms. Approximately 29% of participants will receive the high dose regimen, 29% of participants will receive the middle dose regimen, 14% of participants will receive the low dose regimen, and 29% of participants will receive the placebo.
Study participants must be at least 18 years old with a diagnosis of Graves' disease with hyperthyroidism associated with active, moderate to severe GO with a Clinical Activity Score (CAS) ≥ 4 for the most severely affected eye at Screening and Baseline (on the 7-item scale). Additionally, the onset of active GO must be within 9 months of screening