This study is testing a new medicine called YB-101 for people with Graves' Disease. Graves' Disease is when the thyroid makes too much hormone, causing problems like feeling very tired or shaky. The study checks if YB-101 is safe, if people can handle it well, and how it moves through the body. Participants will either get YB-101 or a placebo, which looks like the medicine but has no medicine in it. You can't join both parts of the study. You will have 34-39 clinic visits over about 40 weeks.

• This study lasts about 40 weeks with many clinic visits.
• Participants receive either YB-101 or a placebo as a shot.
• You cannot join if you are pregnant or have had certain thyroid treatments.

To join, you need to have Graves' Disease and not have had certain treatments, like radioactive iodine. Make sure to talk to your doctor to see if this study is right for you!