A Phase 3 Study of Obexelimab in Patients With IgG4-Related Disease

This study consists of a 1-year randomized control period (RCP), followed by an additional 3-year open label extension (OLE) period. To enter the Screening Period (Day -28 to Day -1), patients must have active IgG4-RD signs/symptoms (i.e., flare) that require steroid therapy. On Day 1, patients will be randomized in a ratio of 1:1 to receive either obexelimab or placebo administered as subcutaneous (SC) injections. All patients will begin a steroid taper on Day 1 to discontinuation by Week 8. Patients will be monitored for flares during scheduled in clinic visits and any unscheduled visits. The primary endpoint is time to first IgG4-RD flare that requires initiation of rescue therapy in the opinion of the investigator and the Adjudication Committee (AC). Following the 52-week RCP, patients will have the opportunity to continue in an OLE period where all patients will receive obexelimab. During the OLE, a subset of patients may be eligible to participate in a sub-study evaluating the immune response to vaccination while receiving obexelimab treatment. Patients who do not wish to enroll into the OLE period will return for an in-clinic safety follow-up visit 8 weeks after the Week 52 visit (i.e., Week 60). Including screening and follow-up, the maximum duration of participation in this study for an individual patient is 224 weeks (i.e., 28-day screening, 52-week RCP, 156-week OLE, and a 12-week follow-up).