This study is testing a new treatment called efgartigimod PH20 SC for people with a condition called Idiopathic Inflammatory Myopathy (IIM). IIM is when your muscles get inflamed and weak for no known reason. The study will compare how well this treatment works against a placebo (a pill with no medicine) by looking at the Total Improvement Score (TIS). People with certain types of IIM, like dermatomyositis (DM) and immune-mediated necrotizing myopathy (IMNM), can join. To join, participants must have a clinical diagnosis, active disease symptoms, and meet other health criteria.

• Study Length: Check with the study team for the exact duration and number of visits.
• Compensation: Participants may receive compensation; ask the study team for details.
• Risks: There may be risks like new symptoms; discuss all potential risks with your doctor.

For more details, you can visit the study's website: https://myositis-study.com/