This study is being done in adults with Graves’ Disease, a condition in which the immune system makes the thyroid gland work too hard. The treatment being studied is IMVT-1402 (imeroprubart), given as a subcutaneous injection, which means an injection under the skin. The purpose of the study is to see how well this treatment works over time and whether it is safe and well tolerated.

The study follows people for a long period and looks at whether normal thyroid function can be kept after treatment has been stopped. During the study, adults receive the study medicine and are then observed over time to see whether thyroid levels remain stable without ATD (anti-thyroid drugs, medicines that lower thyroid hormone). Some participants may stop the study medicine earlier or later than others as part of the study plan. The study also checks whether TRAb (thyroid-stimulating hormone receptor antibodies, proteins made by the immune system that can affect the thyroid) are no longer found in the blood.

The study is designed as a long-term extension, meaning it continues to follow people who have already taken part in earlier research with this medicine. Information is collected over many months, with the main follow-up lasting up to 52 weeks after treatment changes. The study uses groups of participants to compare how long thyroid control lasts after stopping treatment and how often the disease returns, also called a relapse.