A Study to Assess the Efficacy, Safety, and Tolerability of IMVT-1402 as Treatment for Adult Participants With Graves' Disease

This trial is open to adults aged between 18 and 75 who have been diagnosed with Graves' disease. To be considered, your thyroid must still be overactive even though you are already taking standard antithyroid tablets. You also need to be able to attend regular clinic visits and follow the study instructions.

You cannot take part if you have already had your thyroid gland removed through surgery, or if you have previously had radioactive iodine therapy that successfully treated your condition. These treatments permanently change how the thyroid works, which means the study medicine cannot be tested fairly.

People with moderate or severe active thyroid eye disease (a condition linked to Graves' that causes swelling or bulging of the eyes) cannot join if they are likely to need urgent treatment or eye surgery during the trial. You may also be unable to take part if you have another significant autoimmune condition that requires treatment that could put your health at risk.

Taking part in this study involves regular visits to a hospital or specialist research clinic. During these visits, doctors and nurses will closely monitor your general health. You will have regular checks such as blood tests to measure your thyroid hormone levels, blood pressure readings, and heart checks (ECGs). You will be given either the study medicine (IMVT-1402) or a dummy treatment (placebo). You will also be asked about how you are feeling and any symptoms or changes you notice. The study team will explain the exact schedule of clinic visits and how long you will need to take part before you decide to sign up.