Immune Thrombocytopenia (ITP) is a rare, serious autoimmune disease that can worsen over time. ITP occurs when the immune system mistakenly attacks and destroys the blood-clotting cells in the body (called platelets). Bleeding can occur when platelet levels are low in the blood. If the platelet count is very low, the bleeding can be serious. Bleeding can occur from the skin, brain, and other body parts. Primary ITP means no specific cause of a low platelet count can be found.

The Advance Next study is designed to assess the safety and efficacy of the investigational study drug* (called efgartigimod) compared to a placebo for the treatment of adults living with primary ITP.

The study is blinded, meaning that neither the study participant nor the study team will know if the participant is receiving the investigational study drug or placebo.

*The investigational study drug has not been approved by any regulatory agency for use in ITP as efficacy and safety have not been established, except for Japan where PMDA approval was received.

You may be eligible to participate if you:

• Have been diagnosed with primary ITP at least 1 year ago
• Have previously received at least one treatment for ITP with insufficient response
• Are at least 18 years old
• Meet additional criteria that the study staff will discuss
• Are willing to have close medical care and follow-up examinations throughout the study

The study will last for up to 138 weeks (about 2.5 years) and during this period study participants might need to visit the study site up to 138 times.

Treatment period:

Both the investigational study drug and placebo are given through an intravenous (into a vein) infusion either weekly or every other week.

Open-Label period:

All participants will receive the investigational study drug.

Safety follow-up period:

As part of the efficacy and safety measures in the study, all enrolled participants will be monitored and supported by the study team. Part of this process will include a series of health questions, physical examinations, and blood and urine tests.