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

• Change in mean Inflammatory Neuropathy Cause and Treatment (INCAT) scores during the SC treatment period [ Time Frame: SC week 1, SC week 25 ] [ Designated as safety issue: No ]
• Change in mean maximum grip strength scores during the SC treatment period [ Time Frame: SC week 1, SC week 25 ] [ Designated as safety issue: No ]
• Change in mean Medical Research Council (MRC) sum scores during the SC treatment period [ Time Frame: SC week 1, SC week 25 ] [ Designated as safety issue: No ]
• Time to CIDP relapse [ Time Frame: up to 24 weeks ] [ Designated as safety issue: No ]
• Rate of adverse events per SC infusion [ Time Frame: 24 weeks ] [ Designated as safety issue: Yes ]
• Number of subjects with adverse events during the SC Treatment Period [ Time Frame: 24 weeks ] [ Designated as safety issue: Yes ]
• Percentage of subjects with adverse events during the SC Treatment Period [ Time Frame: 24 weeks ] [ Designated as safety issue: Yes ]

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 on intravenous immunoglobulin (IVIG) maintenance therapy enrolled in the study will be assessed during 3 separate study periods. Patients first undergo an IVIG Withdrawal Period of up to 12 weeks to test for ongoing need of IgG. Those patients experiencing CIDP relapse during the withdrawal period will be administered IVIG 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 INCAT score, maximum grip strength, the Medical Research Council (MRC) sum score, the Rasch-built Overall Disability Scale (R-ODS), and electrophysiological evaluations.

• Chronic Inflammatory Demyelinating Polyneuropathy
• Polyradiculoneuropathy

• Biological: IgPro20

  20% liquid formulation (200 mg/mL) of human normal immunoglobulin for subcutaneous use administered weekly during the SC treatment period of the study according to the randomization:

  0.2 g/kg body weight (low dose arm)

  0.4 g/kg body weight (high dose arm)

  Other Name: Hizentra
• Biological: Placebo
  2% human albumin administered by weekly SC infusions during the SC treatment period of the study.

• Experimental: IgPro20 low dose
  Intervention: Biological: IgPro20
• Experimental: IgPro20 high dose
  Intervention: Biological: IgPro20
• Placebo Comparator: Placebo
  Intervention: Biological: Placebo

Inclusion Criteria:

• Definite or probable CIDP according to the European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) criteria 2010.
• Repeated treatment with IVIG (≥ 4 infusions) within the last 9 months prior to enrollment.
• An IVIG treatment during the last 8 weeks prior to enrollment.
• Age ≥18 years.
• Written informed consent for study participation obtained before undergoing any study-specific procedures.

Exclusion Criteria:

• Any polyneuropathy of other causes
• Any other disease (mainly neurological or chronic orthopedic) that has caused neurological symptoms or may interfere with treatment or outcome assessments
• Severe diseases and conditions that are likely to interfere with evaluation of the study product or satisfactory conduct of the study
• History of thrombotic episodes within the 2 years prior to enrolment
• Known allergic or other severe reactions to blood products including intolerability to previous IVIG