A Proof-of-Concept Study to Assess Batoclimab in Participants With Graves' Disease

Inclusion Criteria: * Have serologically confirmed GD as documented by presence of elevated stimulatory thyrotropin receptor antibody (TSH-R-Ab) level (i.e., \> specimen-to-reference ratio of 140%) at the Screening Visit. * Have active hyperthyroidism due to GD with the following laboratory values at the Screening Visit: * TSH \< LLN * FT3 \> upper limit of normal (ULN) and \<=5 \* ULN * FT4 \> ULN and \<=5 \* ULN Note: Participants who have T3 thyrotoxicosis (i.e TSH \<LLN, FT3 \> ULN and ≤5× ULN, but FT4 within normal range) at the Screening Visit may be enrolled, if they have serologically confirmed GD as per Inclusion Criterion 1. * Are willing and capable of giving written informed consent, which includes being able to comply with all aspects of the study treatment and testing schedule. Exclusion Criteria: * History of hyperthyroidism not caused by GD (e.g., toxic adenoma or toxic multinodular goiter), and/or history or presence of thyroid storm. * History of treatment with radioactive iodine or thyroid surgery. * Total immunoglobulin G (IgG) level \<6 grams per liter (g/L) at the Screening Visit. * Albumin level \<3.5 grams per deciliter (g/dL) (\<35 g/L) at the Screening Visit. * Absolute neutrophil count \<1000 cells per cubic millimeter (cells/mm\^3) at the Screening Visit. Other, more specific exclusion criteria are defined in the protocol.