A Study to Evaluate the Pharmacokinetics and Safety of XEMBIFY Versus Gamunex-C in Participants With Chronic Inflammatory Demyelinating Polyradiculoneuropathy

The main goal of the study is to find out whether XEMBIFY, given once a week under the skin, provides similar levels of immunoglobulin G in the blood over time as Gamunex-C, which is given into a vein once every 3 weeks in people with CIDP. Participants with CIDP will first have up to 28 days of screening to make sure they can join the study. Those who qualify will then start a 19-week treatment period with Gamunex-C. During this period, they will receive Gamunex-C through a vein once every 3 weeks, for a total of 7 doses. Approximately, one week after their last Gamunex-C dose, they will begin a 16-week treatment period with XEMBIFY under the skin, once a week for a total of 16 doses. Blood samples will be collected during both treatment periods to measure IgG level in the blood.