An Open-Label Study to Determine if BHV-1300 is Safe in Adults With Graves' Disease

Key Inclusion Criteria:

• Rollover participants have completed either parent study BHV1300-202 or BHV1300-302.

• De novo Participants must have:

  • Serologically confirmed Graves' disease as documented by presence of elevated antibodies
  • Active hyperthyroidism due to Graves' disease

Key Exclusion Criteria:

• Rollover participants must not have met early termination criteria in the parent study

• De novo participants Key Exclusion:

  • History of hyperthyroidism not caused by Graves' Disease (e.g., toxic adenoma or toxic multinodular goiter)
  • Have received levothyroxine, desiccated thyroid extract, or T3 at any dose within six weeks of the Baseline/Day 1 visit.
  • Thyroid storm, i.e. severe thyrotoxicosis with evidence of systemic decompensation (e.g., Burch-Wartkofsky Point Scale of ≥ 45 or Japanese Thyroid Association category 1 or 2, with accompanying manifestations including hyperpyrexia, tachycardia, arrhythmias, congestive heart failure, agitation, delirium, psychosis, stupor, and coma, as well as nausea, vomiting, diarrhea, or hepatic failure) within 6 weeks of Screening
  • Have autoimmune disease other than Graves' disease requiring treatment
  • Have moderate to severe thyroid eye disease (TED) or are expected to require immediate surgical intervention and/or are planning corrective surgery/irradiation or medical therapy for TED during study participation.
  • Are expected to require urgent or emergent thyroid surgery or ablation within six weeks of Baseline/Day 1 or throughout the study.