RecruitingPhase 3Biological interventionA Study to Compare TAK-881 and HYQVIA in Adults With Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP)The main aim of this study is to evaluate the pharmacokinetic (PK) comparability between TAK-881 and HYQVIA subcutaneous (SC) administration for maintenance therapy of CIDP. The participants who are already receiving intravenous immunoglobulin G (IGIV), conventional subcutaneous intravenous immunoglobulin G (cIGSC), or HYQVIA will be treated with the same dose equivalent as their prior IG treatment with HYQVIA for 20 weeks followed by TAK-881 for 24 weeks. Participants will need to visit the clinic every 3 or 4 weeks until they enter the extension phase. In the extension phase, home infusions are allowed, and visits will occur between every 12 weeks and 24 weeks.