Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) and Treatment With Subcutaneous Immunoglobulin (IgPro20)

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 doses (0.2 or 0.4 g/kg body weight) or placebo.

The overall study duration is up to 52 weeks. Clinical outcomes will be assessed by the
Inflammatory Neuropathy Cause and Treatment (INCAT) score, maximum grip strength, the Medical
Research Council (MRC) sum score, the Rasch-built Overall Disability Scale (R-ODS), and
electrophysiological evaluations.