Study Purpose: This research tests if the medicine obexelimab can prevent flare-ups in people with IgG4-Related Disease (IgG4-RD), a condition where the immune system causes problems in different body parts.

Study Details: The study lasts up to 116 weeks. It starts with a 1-year randomized control period (RCP) where participants get either obexelimab or a placebo (a fake treatment) through injections. After that, there’s an optional 1-year period where everyone receives obexelimab. You must visit the clinic for check-ups to monitor flare-ups, which are sudden worsening of symptoms that might need extra treatment. The main goal is to see how long it takes for a flare-up requiring rescue therapy to occur. If you don't join the second year, you need a safety check 8 weeks after the first year.

• Participation lasts up to 116 weeks, including screening and follow-up.
• You must have active IgG4-RD symptoms that need steroid treatment.
• During the study, you’ll receive injections and regular check-ups.

Consider: Before joining, make sure you meet the eligibility criteria and are okay with the time commitment and medical procedures involved. Discuss with your doctor if this study suits you.