Chronic Inflammatory Demyelinating Polyneuropathy

This is a prospective, multicenter, randomized, double-blind, placebo-controlled, parallel-group 3-arm study to investigate 2 different doses of subcutaneous (SC) IgPro20 compared with placebo for maintenance treatment of patients with CIDP. Patients who received at lease 1 dose of intravenous immunoglobulin (IVIG) within 8 weeks before screening will be assessed during 4 separate study periods. Patients first undergo a Screening Period, followed by an IgG Dependency Test Period of up to 12 weeks to test for ongoing need of IgG. Those patients experiencing CIDP relapse during this test period will be administered a standardized IVIG regimen during an IVIG Re-stabilization Period. Patients with improved and maintained adjusted inflammatory neuropathy cause and treatment scale (INCAT) in the IVIG Re-stabilization Period will continue to the SC Treatment Period of the study. Patients entering the 24 week SC Treatment Period will be randomized to receive weekly infusions of 1 of 2 IgPro20